Propylene polymer composite film, its manufacturing method and use

Abstract

A propylene polymer-based composite film, its manufacturing method, and its use are disclosed. The composite film comprises at least two distinct layers: layer a and layer b. Layer a and layer b each comprise at least one propylene polymer, and at least one of layers a and b comprises a propylene impact copolymer. The propylene impact copolymer comprises an elastic moiety that forms a dispersed band-like rubber phase in the composite film. The rubber phases are arranged parallel to each other, with an average transverse dimension of 20 to 200 nm and an average aspect ratio of 5 to 20. The composite film has both excellent impact resistance and optical properties, good tensile properties and / or good heat seal strength at lower heat seal temperatures, and good uniformity. The composite film is particularly useful in the field of packaging materials, particularly battery packaging, electronic product packaging, and food packaging.

Description

[Technical Field]

[0001] The present invention relates to the field of polymer films, and in particular to a propylene polymer-based composite film, its manufacturing method and use, and packaging materials containing said composite film. [Background technology]

[0002] Polypropylene films can be typically produced by methods such as casting and biaxial stretching, but polypropylene films prepared from homopolypropylene raw materials typically have relatively low impact strength. Polypropylene films are often used for packaging, which requires the film to have relatively high impact properties. At the same time, it is also desirable for the film to have good optical properties for content visualization and aesthetic appeal.

[0003] To improve the impact properties of polypropylene films, films can be prepared using impact polypropylene or polyolefin elastomers can be added to polypropylene, but the films prepared by these methods usually have high haze and poor optical properties such as transparency. It is also possible to reduce the haze of the film by simultaneously adding a nucleating agent to the film to refine the crystals in the film, but this method leads to a decrease in impact properties.

[0004] Multilayer coextrusion can also be used to prepare films to improve their impact resistance and toughness. For example, in CN101913279A, a three-layer coextrusion method was used to prepare a composite film. The layers in the film contained elastomer and PP mixed in a ratio of 1:10 to 1:3, with the elastomer imparting good impact resistance. However, this method suffers from the problem of difficulty in achieving uniform dispersion when the elastomer content is high. The elastomer typically has poor flowability, resulting in uneven film surfaces and large thickness differences along the machine direction (MD) and transverse direction (TD), making it difficult to obtain films with good optical properties. Furthermore, there is a certain limit to the amount of elastomer added. This is because, once a certain amount is added, phase separation issues arise, limiting further improvement in impact resistance. In addition, during the multilayer coextrusion process, the elastomer can also cause significant differences in flowability between the core and surface layers, further exacerbating the uneven film surface and potentially resulting in inconsistent properties at various points in the film. Different rheological properties of the raw materials between layers also affect the uniformity of the film, affecting the optical and mechanical properties of the film.

[0005] It is difficult for current propylene polymer-based films to simultaneously have good optical properties and impact resistance. Furthermore, when propylene polymer films are used in packaging applications, it is generally desirable to have good heat-sealing properties at relatively low heat-sealing temperatures, and prior art propylene polymer films cannot meet such property requirements. Furthermore, current composite films have insufficient uniformity in thickness and properties. Summary of the Invention

[0006] SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned prior art, and aims to provide a propylene polymer film having low haze and high impact resistance, and a method for producing the same, which simultaneously has good impact resistance and optical properties.

[0007] Another object of the present invention is to provide such a film, which may further have good mechanical properties (such as tensile properties) and / or good heat seal strength at relatively low heat seal temperatures.

[0008] Another object of the present invention is to provide a propylene polymer-based transparent impact-resistant composite film that simultaneously has good impact resistance and optical properties, and good uniformity of film thickness and properties.

[0009] Another object of the present invention is to provide a method for preparing a composite film, which has a stable preparation process and good uniformity of the resulting film.

[0010] According to the present invention, it has been found that by using a propylene impact copolymer containing a specific elastic portion as a raw material for at least one layer of a composite film and by extrusion casting, a composite film containing a specific microstructure in which a band-like rubber phase is uniformly dispersed can be prepared, thereby achieving the above-mentioned object.

[0011] According to a first aspect, the present invention provides a propylene polymer-based composite film comprising at least two distinct layers, layer a and layer b, wherein layers a and b each comprise at least one propylene polymer, and at least one of layers a and b comprises a propylene impact copolymer; the propylene impact copolymer comprises an elastic portion that forms a dispersed rubber band phase in the composite film.

[0012] According to a second aspect, the present invention provides a method for preparing the composite film of the present invention, comprising the step of extrusion casting raw material compositions for forming each layer to form a composite film.

[0013] According to a third aspect, the present invention provides the use of the composite film of the present invention in the field of packaging materials.

[0014] According to a fourth aspect, the present invention provides a packaging material comprising the composite film of the present invention.

[0015] Other aspects and beneficial effects of the present invention will become apparent from the following detailed description of the invention and the examples section, taken in conjunction with the drawings.

[0016] DESCRIPTION OF THE DRAWINGS Exemplary embodiments of the invention will now be described in more detail in conjunction with the drawings. [Brief explanation of the drawings]

[0017] [Figure 1] 1a and 1b are schematic diagrams for the selection of sampling points for films of the present invention. [Figure 2] 1 is a scanning electron microscope (SEM) photograph of a cross section of a test piece of the raw propylene impact copolymer used in Example A1 according to the present invention. [Figure 3] 1 is an atomic force microscope photograph of a cross section of the film of Example A1 according to the present invention. [Figure 4] 1 is an atomic force microscope photograph of a cross section of a film of Comparative Example A3, which is not the present invention. [Figure 5] 1 is an atomic force microscope photograph of a cross section of the film of Example C1 according to the present invention. [Figure 6] Figure 6a is an SEM photograph of a cross section of a test piece of the raw propylene impact copolymer used in Example E1 according to the present invention, and Figure 6b is an SEM photograph of a cross section of a test piece of the raw propylene impact copolymer used in Comparative Example E1, not according to the present invention. [Figure 7] 1 is an atomic force microscope photograph of a cross section of the film of Example E1 according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0018] According to a first aspect, the present invention provides a propylene polymer-based composite film comprising at least two distinct layers, layer a and layer b, wherein layers a and b each comprise at least one propylene polymer, and at least one of layers a and b comprises a propylene impact copolymer; the propylene impact copolymer comprises an elastic portion that forms a dispersed rubber band phase in the composite film.

[0019] As used herein, the term "dispersed" means that the rubber phase is not continuously distributed in the composite film. As shown by the black areas in Figures 3, 5, and 7, the rubber phase can be examined by observing the cross section of the composite film cut along the transverse direction (TD) with an atomic force microscope (AFM), and the rubber phase is uniformly dispersed in the film matrix in the form of multiple bands.

[0020] As used herein, the term "band" generally refers to a shape having an aspect ratio greater than two.

[0021] As used herein, the aspect ratio refers to the ratio of the vertical axis of an object to the horizontal axis. The vertical axis refers to the longest dimension of the object (here, the rubber phase), i.e., the distance between the two furthest points on the outline of the object. The horizontal axis refers to the length between the intersection points of the line perpendicular to the vertical axis that has the longest distance between the intersection points of the line that intersects with the outline of the object.

[0022] In the composite film of the present invention, the average horizontal size of the rubber phase may be 20 to 200 nm, more preferably 20 to 150 nm, and the average aspect ratio of the rubber phase may be 5 to 20, preferably 5 to 15.

[0023] The size and aspect ratio of the transverse axis are measured by observing the cross section of the composite film cut along the transverse direction (TD) using an atomic force microscope. From 200 sampling points, the average size of the transverse axis of the rubber phase is calculated as the average size of the transverse axis of the rubber phase, and the average aspect ratio of the rubber phase is calculated as the average aspect ratio of the rubber phase.

[0024] Machine direction (MD) refers to the direction of the machine cut. Cross direction (TD) refers to the direction perpendicular to the machine cut direction.

[0025] In the composite film of the present invention, the rubber phases are advantageously arranged parallel to one another.

[0026] As used herein, the term "parallel arrangement" means that the cross sections of the rubber phase are arranged parallel to one another along a certain direction, excluding a small number of rubber phase particles that are arranged in different directions in local areas due to the preparation process and that do not match the overall arrangement direction of the rubber phase particles in the entire composite film, and rubber phase particles that cannot be clearly observed by the preparation process or AFM method.

[0027] As used herein, "parallel orientation" includes a situation in which the cross sections of the rubber phases are at an angle relative to each other of no more than about 10 degrees, preferably less than about 5 degrees.

[0028] In the present invention, both Layer a and Layer b contain at least one propylene polymer, and furthermore, both are composed of propylene polymer-based compositions, but they differ in specific composition and / or thickness. The entire composite film is a propylene polymer-based composite film, and can also be called a polypropylene composite film.

[0029] In the present invention, layer a is intended to be used as the core layer of the composite film, i.e., a layer relatively far from a medium that the composite film will come into contact with during use, and layer b is intended to be used as a surface layer of the composite film, i.e., a layer close to a medium that the composite film will come into contact with during use, such as an electrolyte that a battery packaging material will come into contact with.

[0030] According to the present invention, at least one of the layers a and b contains the propylene impact copolymer having a specific elastic portion, so that the entire composite film contains a specific dispersed rubber phase.

[0031] The elastic segments may appear as spherical or nearly spherical rubber phases in scanning electron micrographs of impact specimens of the propylene impact copolymer.

[0032] The propylene impact copolymer is preferably a propylene impact copolymer containing ethylene units, and the elastic portion is a copolymer portion containing ethylene units, preferably selected from the group consisting of an ethylene-propylene copolymer portion and an ethylene-butylene copolymer portion.

[0033] Preferably, the propylene impact copolymer comprises a propylene homopolymerized portion and the ethylene unit-containing copolymerized portion. The propylene homopolymerized portion may comprise an isotactic polymerized structure.

[0034] 13 The content of the ethylene unit-containing copolymer moiety in the propylene impact copolymer, as measured by CNMR, is preferably 3 to 15% by weight, more preferably 7 to 12% by weight.

[0035] The ethylene unit content of the propylene impact copolymer is preferably 1 to 14 wt%, more preferably 3 to 12 wt%, based on the total weight of the propylene impact copolymer. The ethylene unit content of the room temperature xylene soluble matter of the propylene impact copolymer is preferably 40 wt% or less. 13 The content of ethylene unit sequences [EEE] as measured by CNMR is preferably 20% by weight or less.

[0036] The propylene impact copolymer may have a block structure or may include a propylene block copolymer.

[0037] The melt flow rate (MFR) of the propylene impact copolymer, measured according to standard GB / T3682-2000 at 230°C under a load of 2.16 kg, can be 1-10 g / 10 min, preferably 1-8 g / 10 min, where the measurement temperature is 230°C and the load is 2.16 kg.

[0038] Usable propylene impact copolymers are commercially available, for example, propylene impact copolymer from SINOPEC SABIC Petrochemical Co. under the trade name EP200K, propylene impact copolymer from Shanghai Petrochemical Co. under the trade name F200R and M180R, propylene impact copolymer from Maoming Petrochemical Co. under the trade name PPB-M02D, and propylene impact copolymer from Korean Hyosung under the trade name J410F.

[0039] Propylene impact copolymers can also be prepared by continuous polymerization in the presence of a highly stereoselective Ziegler-Natta catalyst. Continuous polymerization means that the preparation process comprises at least two consecutive steps, in which the elastic and non-elastic portions are prepared in separate steps, and except for the first step, the latter step is carried out in the presence of the polymer formed in the previous step and the catalyst used in the previous step.

[0040] Layer a may comprise homopolypropylene and / or propylene random copolymer.

[0041] The melt flow rate of the homopolypropylene measured in accordance with the GB / T 3682-2000 standard at 230°C under a load of 2.16 kg is preferably 2 to 15 g / 10 min, the measurement temperature being 230°C and the load being 2.16 kg. 13 The isotacticity of the homopolypropylene, as measured by CNMR, is preferably greater than 97%. The molecular weight distribution Mw / Mn of the homopolypropylene, as measured by gel permeation chromatography (GPC), is preferably 4.5 to 7.0. Usable homopolypropylene is commercially available, for example, homopolypropylene with the trade name PPH-FA03 from Qingdao Refining & Chemical Co., homopolypropylene with the trade name PPH-FA03 from Zhongyuan Petrochemical Co., and homopolypropylene with the trade name FC801 from Shanghai Petrochemical Co. Alternatively, the homopolypropylene can be prepared by a conventional method in the art.

[0042] The propylene random copolymer may be a copolymer of propylene and ethylene and / or butene, such as an ethylene-propylene-butene ternary random copolymer, a propylene-ethylene binary random copolymer, or a propylene-butene binary random copolymer. The melt flow rate of the random propylene copolymer, measured at 230°C under a 2.16 kg load according to GB / T 3682-2000, may be 2 to 15 g / 10 min, preferably 2 to 10 g / 10 min. The molecular weight distribution Mw / Mn of the random copolymer, measured by GPC, is preferably 4.5 to 7.0. Usable propylene random polymers are commercially available, such as the random propylene copolymer F5006 from Yanshan Petrochemical Co. and the random propylene copolymers F500EPS, F800EDF, or F800EPS from Shanghai Petrochemical Co. Alternatively, these propylene random copolymers can be prepared by conventional methods in the art.

[0043] Layer b may contain a propylene random copolymer. The propylene random copolymer is as described above. The propylene random copolymer in layer b and the propylene random copolymer in layer a may be the same or different. For example, layer b may contain 60 to 100 wt % of the propylene random copolymer.

[0044] In a preferred embodiment, at least one of layers a and b may comprise a polyolefin elastomer, thereby advantageously further improving the impact resistance of the composite film.

[0045] The polyolefin elastomer may be an elastomeric copolymer of ethylene and an α-olefin. The α-olefin is preferably a C3-C 12The polyolefin elastomer is an α-olefin, and more preferably at least one selected from the group consisting of propylene, 1-butene, 1-hexene, and 1-octene. Usable polyolefin elastomers are commercially available, such as polyolefin elastomers with the trade name 8200 from Dow, polyolefin elastomers with the trade name 8411 from Dow, polyolefin elastomers with the trade name DF640 or DF840 from Mitsui, and polyolefin elastomers with the trade name 6102, VM3980, or EXACT3139 from Exxon. Alternatively, the polyolefin elastomer can be prepared by a conventional method in the art.

[0046] When a polyolefin elastomer is used in the composite film, the elastic portion of the propylene impact copolymer and the polyolefin elastomer form a dispersed rubber phase in the composite film, which is also in the form of bands arranged parallel to each other. The average size of the transverse axis of such rubber phases may be 20 to 200 nm, preferably 20 to 150 nm. The average aspect ratio of the rubber phase may be 5 to 20, preferably 5 to 15. The size is measured by AFM as described above.

[0047] The presence of polyolefin elastomer can advantageously compensate for the possible problem of uneven distribution of the rubber phase in propylene impact copolymers, thereby improving the uniformity of the various points of the film with regard to impact properties.

[0048] In a preferred embodiment, 160 r at 230°C -1 and 640r -1 Shear viscosity ratio η of polyolefin elastomer at shear rate 160 / η 640 is 1.2 to 3, preferably 1.7 to 2.3. -1 Shear viscosity η of polyolefin elastomer at shear rate 640is preferably 100 to 500 Pa·s, more preferably 140 to 400 Pa·s. 160 and η 640 is measured using a capillary rheometer according to ISO11443:2014.

[0049] The melt flow rate of the material constituting layer a (propylene polymer composition) measured in accordance with standard GB / T3682-2000 at 230°C under a load of 2.16 kg may be 2 to 10 g / 10 min, preferably 2 to 8 g / 10 min, more preferably 3 to 7 g / 10 min, at a measurement temperature of 230°C and a load of 2.16 kg.

[0050] The melt flow rate of the material constituting layer b (propylene polymer composition), measured in accordance with standard GB / T3682-2000 at 230°C under a load of 2.16 kg, is 2 to 10 g / 10 min, preferably 3 to 10 g / 10 min, more preferably 3 to 9 g / 10 min, more preferably 4 to 8 g / 10 min, at a measurement temperature of 230°C and a load of 2.16 kg.

[0051] The above melt flow rate can advantageously make the film preparation process more stable, and the uniformity, mechanical properties and optical properties of the film are better.

[0052] Both layers a and b may contain the propylene impact copolymer, and the propylene impact copolymer of layer a and the propylene impact copolymer of layer b may be the same or different. It is also possible for only one of layers a and b to contain the propylene impact copolymer.

[0053] Both layer a and layer b may contain the polyolefin elastomer, and the polyolefin elastomer in layer a and the polyolefin elastomer in layer b may be the same or different. Preferably, the ratio of the weight proportion of the polyolefin elastomer in layer a to the weight proportion of the polyolefin elastomer in layer b is 6:1 to 1:6. It is also possible for only one of layer a and layer b to contain the polyolefin elastomer.

[0054] Both layer a and layer b may comprise the propylene impact copolymer and the polyolefin elastomer, and the propylene impact copolymer of layer a and the propylene impact copolymer of layer b may be the same or different, and the polyolefin elastomer of layer a and the polyolefin elastomer of layer b may be the same or different.

[0055] It is also possible that only one of layers a and b contains the propylene impact copolymer, and one or both of layers a and b contain the polyolefin elastomer; or it is also possible that only one of layers a and b contains the polyolefin elastomer, and one or both of layers a and b contain the propylene impact copolymer.

[0056] In one embodiment, layer a comprises the homopolypropylene, the propylene impact copolymer and the polyolefin elastomer, and layer b comprises the random propylene copolymer and the polyolefin elastomer.

[0057] In this embodiment, the weight ratio of the polyolefin elastomer in layer a to the weight ratio of the polyolefin elastomer in layer b is preferably 2:1 to 1:4, such as 1.5:1, 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, and any value therebetween, more preferably 1:1 to 1:2. When coextrusion of a bilayer or multilayer film is performed, the above ratio of the weight ratio of the polyolefin elastomer in layer a to the weight ratio of the polyolefin elastomer in layer b can further improve the impact resistance and optical properties of the composite film, while making the extrusion process more stable.

[0058] Specifically, in this embodiment, Layer a may contain 40 to 90 wt%, preferably 50 to 90 wt%, more preferably 55 to 75 wt% of the homopolypropylene, 5 to 40 wt%, preferably 10 to 30 wt% of the propylene impact copolymer, and 2 to 30 wt%, preferably 5 to 20 wt% of the polyolefin elastomer, each based on the total weight of Layer a. Layer b may contain 40 to 95 wt%, preferably 60 to 95 wt%, more preferably 75 to 90 wt% of the random propylene copolymer, and 5 to 60 wt%, preferably 5 to 40 wt%, more preferably 10 to 25 wt% of the polyolefin elastomer, each based on the total weight of Layer b.

[0059] A composite film including such a surface layer and a core layer has the advantage of not only having excellent optical properties but also being able to improve heat seal strength.

[0060] In the above embodiment, when both the polyolefin elastomers of layers a and b satisfy the following conditions, the thickness uniformity and property uniformity of the film can be further improved: 160r at 230°C -1 and 640r -1 Shear viscosity ratio η at a shear rate of 160 / η 640 is 1.2 to 3, preferably 1.7 to 2.3, and is 640r at 230°C. -1Shear viscosity η at a shear rate of 640 is 100 to 500 Pa·s, and preferably 140 to 400 Pa·s.

[0061] Further, preferably, the propylene polymer composition constituting the layer a and the propylene polymer composition constituting the layer b are 160°C at 230°C. -1 The difference in shear viscosity (ηA 160 -ηB 160 ), and 640r at 230°C -1 The difference in shear viscosity (ηA 640 -ηB 640 ) are both controlled to be greater than or equal to 0, and the two (ηA 160 -ηB 160 ) / (ηA 640 -ηB 640 ) is 1 to 2.6, preferably 1.4 to 2.5, and more preferably 1.5 to 2.2, and by adjusting the degree of matching of the fluidity of the raw materials of the various layers, the uniformity of the film thickness and properties can be further improved.

[0062] In another embodiment, layer a comprises a propylene polymer and the polyolefin elastomer, and layer b comprises the random propylene copolymer, the polyolefin elastomer, and the propylene impact copolymer. The propylene polymer of layer a may be selected from homopolypropylene and / or the propylene impact copolymer. For example, layer a may comprise 70 to 100 wt. % propylene polymer.

[0063] In this embodiment, the weight ratio of the polyolefin elastomer in layer a to the weight ratio of the polyolefin elastomer in layer b is preferably 10:1 to 1:6, preferably 6:1 to 1:4, more preferably 4:1 to 1:4, for example, 3.5:1, 3:1, 2.5:1, 2:1, 1.5:1, 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, and any value therebetween. When coextrusion of a bilayer or multilayer film is performed, the above-mentioned ratio of the weight ratio of the polyolefin elastomer in layer a to the weight ratio of the polyolefin elastomer in layer b can further improve the impact resistance and optical properties of the composite film, while making the extrusion process more stable.

[0064] Specifically, in the above embodiment, Layer a may contain 50 to 95 wt %, preferably 70 to 95 wt %, more preferably 80 to 95 wt % of the propylene polymer and 5 to 50 wt %, preferably 5 to 30 wt %, more preferably 5 to 20 wt % of the polyolefin elastomer, each based on the total weight of Layer a; Layer b may contain 40 to 90 wt %, preferably 50 to 90 wt %, more preferably 60 to 85 wt % of the random propylene copolymer, 5 to 40 wt %, preferably 5 to 30 wt %, more preferably 5 to 20 wt % of the polyolefin elastomer, and 2 to 30 wt %, preferably 5 to 20 wt % of the propylene impact copolymer, each based on the total weight of Layer b.

[0065] A composite film comprising such a surface layer and core layer not only has improved impact resistance and improved optical and mechanical properties, but also effectively improves the heat seal strength while lowering the heat seal temperature due to the synergistic effect of the propylene-based impact copolymer containing a specific rubber phase and the other components of the surface layer (heat seal layer).

[0066] In another embodiment, layer a comprises the polyolefin elastomer, the propylene impact copolymer, and other types of propylene polymers, which may be selected from the homopolypropylene and / or random propylene copolymers, and layer b comprises the random propylene copolymer and the polyolefin elastomer.

[0067] Specifically, in the above embodiment, layer a may contain 40 to 90 wt% of propylene impact copolymer, 5 to 40 wt% of other types of propylene polymer, and 2 to 30 wt% of polyolefin elastomer, preferably 55 to 75 wt% of propylene impact copolymer, 10 to 30 wt% of other types of propylene polymer, and 5 to 20 wt% of polyolefin elastomer, each based on the total weight of layer b; layer b may contain 40 to 95 wt% of propylene random copolymer and 5 to 60 wt% of polyolefin elastomer, preferably 75 to 90 wt% of propylene random copolymer and 10 to 25 wt% of polyolefin elastomer, each based on the total weight of layer b.

[0068] Such a composite film can simultaneously have good impact resistance, optical properties and tensile properties, and can have good heat seal strength at a lower heat seal temperature.

[0069] As used herein, the weight percentages of all components in each layer add up to 100% by weight.

[0070] [Additives] Layer a and / or layer b may further contain at least one additive selected from the group consisting of additives conventionally used in polymer films, such as antioxidants, lubricants, halogen absorbers, light stabilizers, heat stabilizers, colorants, fillers, slip agents, surface adhesives, electromagnetic shielding agents, flame retardants, insulating additives, anti-blocking agents, and antistatic agents.

[0071] For example, an antioxidant can be used to improve the oxidation resistance of the composite film during processing. The antioxidant can be at least one selected from the group consisting of various antioxidants commonly used in the art, such as antioxidant 1076, antioxidant 1010, antioxidant 168, thioester antioxidants (e.g., DLTP, DSTP), etc. The content of the antioxidant can be 0.1 to 0.8 parts by weight, preferably 0.2 to 0.4 parts by weight, based on 100 parts by weight of the total weight of the layer.

[0072] To improve other properties of the composite film or to impart other properties (e.g., friction, stability, color, antistatic properties, strength, conductivity, insulation, slipperiness, sliding properties, surface adhesion, electromagnetic shielding properties, flame retardancy, anti-blocking effects, etc.) to the composite film, the composite film may further contain at least one other film additive conventionally used in the art, such as lubricants, halogen absorbers, light stabilizers, heat stabilizers, colorants, fillers, lubricants, surface adhesives, electromagnetic shielding agents, flame retardants, insulating additives, anti-blocking agents, and anti-static agents. These film additives may be used in conventional amounts. For example, unless otherwise specified, the content of each other film additive may be 0.01 to 0.5 parts by weight, preferably 0.05 to 0.3 parts by weight, and more preferably 0.05 to 0.15 parts by weight, based on 100 parts by weight of the total weight of the layer.

[0073] For example, a lubricant can be added to the composite film. The lubricant can be a PEG lubricant and / or a monoglyceride lubricant. Based on 100 parts by weight of the total weight of the layer, the content of the lubricant can be 0.01 to 0.5 parts by weight, preferably 0.05 to 0.2 parts by weight.

[0074] The composite film of the present invention can be added with a polar monomer-modified polypropylene as a surface adhesive, thereby improving the adhesion at the interface between the composite film and other materials, thereby obtaining a highly adhesive, high-impact propylene polymer composite film. The polar monomer-modified polypropylene is added particularly to layer b.

[0075] In a preferred embodiment, based on the total weight of layer a, layer a may contain 40 to 90 wt%, preferably 50 to 85 wt%, of homopolypropylene, 5 to 45 wt%, preferably 10 to 30 wt%, of propylene impact copolymer, and 2 to 40 wt%, preferably 5 to 20 wt%, of polyolefin elastomer; based on the total weight of layer b, layer b contains 40 to 99 wt%, preferably 70 to 90 wt%, of propylene random copolymer, 0 to 30 wt%, preferably 5 to 15 wt%, of polyolefin elastomer, and 1 to 30 wt%, preferably 5 to 15 wt%, of polar monomer-modified polypropylene.

[0076] In another preferred embodiment, based on the total weight of layer a, layer a may contain 50 to 100 wt%, preferably 75 to 95 wt%, of polypropylene and 0 to 50 wt%, preferably 5 to 25 wt%, of polyolefin elastomer; based on the total weight of layer b, layer b may contain 30 to 90 wt%, preferably 60 to 85 wt%, of propylene random copolymer, 5 to 40 wt%, preferably 5 to 20 wt%, of polyolefin elastomer, 2.5 to 20 wt%, preferably 5 to 10 wt%, of propylene impact copolymer, and 2.5 to 20 wt%, preferably 5 to 10 wt%, of polar monomer-modified polypropylene.

[0077] The polar monomer of the polar monomer-modified polypropylene may be at least one selected from the group consisting of a hydroxyl group-containing comonomer, a cyano group-containing comonomer, and an anhydride monomer. The hydroxyl group-containing comonomer is preferably a hydroxy acid and / or vinyl alcohol. The cyano group-containing comonomer is preferably a cyanoacrylate. The anhydride monomer is preferably maleic anhydride and / or itaconic anhydride, more preferably maleic anhydride. Maleic anhydride-grafted polypropylene (PP-g-MAH) has both polar groups and olefin nonpolar segments and possesses the basic physical properties of original polypropylene, such as high crystallinity, high strength, and high impact resistance, as well as improved adhesion to other materials.

[0078] Polar monomer modified polypropylenes are commercially available, for example, maleic anhydride modified polypropylene from Mitsui under the trade name QF551A, maleic anhydride modified polypropylene from Bio-master under the trade name CMG9801, and maleic anhydride modified polypropylene from Exxon under the trade name PO1015.

[0079] A conductive filler can be further added to the composite film of the present invention, thereby improving the antistatic properties of the composite film. The conductive filler is preferably added to Layer b. The conductive filler may be added in an amount of 0.1 to 10 parts by weight, preferably 0.5 to 4.5 parts by weight, based on 100 parts by weight of the total weight of the matrix polymer of Layer b.

[0080] The conductive filler may be, for example, at least one selected from the group consisting of carbon black, graphite, carbon nanotubes, carbon fibers, conductive metal particles, conductive metal fibers, and metal oxides. Carbon black conductive fillers include, but are not limited to, at least one selected from the group consisting of acetylene carbon black, superconducting carbon black, and superconducting carbon black. Graphite conductive fillers include, but are not limited to, at least one selected from the group consisting of natural graphite, expandable graphite, expanded graphite, and graphene. Carbon nanotube conductive fillers include, but are not limited to, non-surface-modified or surface-modified single-walled carbon nanotubes and / or multi-walled carbon nanotubes. The conductive metals of the conductive metal particles and conductive metal fibers may each independently be at least one selected from the group consisting of silver, aluminum, copper, iron, nickel, and stainless steel. The conductive metal-coated filler may be at least one selected from the group consisting of lead-plated, nickel-plated, and silver-plated glass spheres, glass fibers, and mica flakes. The metal oxide may include, but is not limited to, at least one selected from the group consisting of titanium oxide, zinc oxide, tin oxide, indium oxide, and cadmium oxide.An antistatic propylene polymer film can be prepared by adding a conductive filler, and its surface resistivity, as measured by a Keithley 6517B electrometer, is 10 2 ~10 8 Ω, preferably 10 2 ~10 4 The antistatic properties of the film are durable and not easily affected by ambient humidity.

[0081] Furthermore, an electromagnetic wave shielding film can be prepared by adding an electromagnetic shielding agent to the composite film. The electromagnetic shielding agent is preferably added to layer b. The electromagnetic shielding agent may be a conductive metal filler and / or a carbon material. The conductive metal filler is preferably conductive metal particles and / or conductive metal fibers. The metals of the conductive metal particles and conductive metal fibers may each independently be one or more selected from the group consisting of silver, aluminum, copper, iron, nickel, and stainless steel. The carbon material is preferably one or more of carbon black, graphite, graphene, and carbon nanotubes. The amount of the electromagnetic shielding agent added may be 5 to 30 parts by weight, preferably 15 to 25 parts by weight, based on 100 parts by weight of the matrix polymer in layer b. The electromagnetic shielding efficiency of the resulting composite film, measured using a flange coaxial test apparatus in accordance with standard SJ20524, can reach 25 dB or more, preferably 28 dB or more, in the electromagnetic wave band of 50 MHz to 1 GHz.

[0082] The electromagnetic shielding agent can also be used in combination with a coupling agent. The coupling agent can improve the compatibility of the electromagnetic shielding agent with the matrix polymer component (resin component) of the propylene polymer composition, and the type, amount, and quantity of the coupling agent can all be selected according to conventional standards in the art. For example, the coupling agent can be selected from titanate coupling agents, such as one or more selected from the group consisting of monoalkoxy titanates, monoalkylpyrophosphate titanates, coordinated titanates, and chelate titanates. Preferably, the titanate coupling agent is selected from tetrabutyl titanate and / or tetraisopropyl titanate. Based on 100 parts by weight of the total weight of the matrix polymer component, the content of the coupling agent can be 1 to 6 parts by weight, preferably 4 to 6 parts by weight.

[0083] A flame retardant may also be added to the composite film to improve flame retardancy. For example, the flame retardant can be added to Layer a and / or Layer b, or to an additional Layer c, in which case Layer c is a flame-retardant functional layer. For example, Layer c may contain 30 to 80 wt %, preferably 40 to 70 wt %, of a propylene polymer and 20 to 70 wt %, preferably 30 to 60 wt %, of a flame retardant, based on the total weight of Layer c. This can achieve an oxygen index of 21% or more, preferably 23% or more, measured according to the method specified in GB / T2406-2008.

[0084] The flame retardant may be at least one selected from the group consisting of metallic or non-metallic hydroxides and / or oxide hydrates, phosphorus-based flame retardants, boron-based flame retardants, antimony-based flame retardants, and intumescent flame retardants. The metallic or non-metallic hydroxides and / or oxide hydrates may be at least one selected from the group consisting of hydroxides and layered double hydroxides of aluminum, magnesium, boron, and zinc. The phosphorus-based flame retardant may be at least one selected from the group consisting of red phosphorus, phosphates, polyphosphates, and phosphoric acid esters. The boron-based flame retardant may be boric acid and / or a borate, preferably ammonium borate and / or zinc borate. The antimony-based flame retardant may be at least one selected from the group consisting of antimony trioxide, antimony pentoxide, and sodium antimonate. The intumescent flame retardant is at least two selected from the group consisting of sulfuric acid, pentaerythritol or its dimer or trimer, butanetetraol, cyclohexane-hexaol, sorbitol, glucose, maltose, starch, resorcinol, ammonium polyphosphate, dicyandiamide, melamine, urea, melamine, glycine, expandable graphite, and carbon nanotubes. In one embodiment, the flame retardant is an intumescent flame retardant, preferably a mixture of ammonium polyphosphate and pentaerythritol, specifically, the weight ratio of ammonium polyphosphate to pentaerythritol is 0.5 to 5:1. In another embodiment, the flame retardant is a mixture of magnesium hydroxide and aluminum hydroxide, specifically, the weight ratio of magnesium hydroxide to aluminum hydroxide is 0.5 to 2:1. Flame-retardant polypropylene films prepared with the flame retardant are advantageous in that they are easy to process and have good properties.

[0085] A colorant may be added to the composite film to impart a colored appearance to the composite film. The colorant may be a conventional choice in the art, including, but not limited to, at least one of azo pigments, phthalocyanine pigments, heterocyclic pigments, lake pigments, dyes, optical brighteners, and fluorescent pigments. All of the above colorants are commercially available. The colorant is preferably added to Layer A. Based on 100 parts by weight of the matrix polymer in Layer A, the content of the colorant may be 0.1 to 1 part by weight, preferably 0.3 to 0.8 parts by weight. Layer A may also contain a dispersant. The dispersant can improve processability and uniformity between the matrix polymer components and the colorant in Layer A. The type, amount, and quantity of the dispersant may all be conventional choices in the art. For example, the dispersant may be a low-molecular-weight polyethylene wax, and the weight content of the dispersant may be 20 to 30% by weight of the colorant.

[0086] The composite film of the present invention may further contain a lubricant. The lubricant may be an amide-based lubricant, preferably at least one of erucamide, oleamide, stearamide, behenamide, stearyl erucamide, and ethylene bisstearamide. Alternatively, the lubricant may be a mixture of an amide-based lubricant and a migration-resistant lubricant, and the amide-based lubricant is preferably at least one of erucamide, oleamide, stearamide, behenamide, stearyl erucamide, and ethylene bisstearamide. The migration-resistant lubricant is preferably at least one of polytetrafluoroethylene microparticles, polyimide microparticles, polyamide microparticles, polycarbonate microparticles, silicone, nano-calcium carbonate, mica, and nano-silica. The weight ratio of the amide-based lubricant to the migration-resistant lubricant is preferably 1:20 to 1:1, preferably 1:10 to 1:2. The particle size of the migration-resistant lubricant contained in the lubricant may be in the range of 0.1 to 5 μm, preferably 0.3 to 2 μm.

[0087] The lubricant can be added to layer a and / or layer b in an amount of 0.01 to 1.5% by weight, preferably 0.08 to 0.6% by weight, based on the total weight of each layer.

[0088] Preferably, the lubricant is added to both layer a and layer b.

[0089] Preferably, the molecular weight of the amide-based lubricant in the layer b is equal to or greater than the molecular weight of the amide-based lubricant in the layer a.

[0090] Particularly preferably, an amide-based lubricant is added to layer a, and a mixture of an amide-based lubricant and a migration-resistant lubricant is added to layer b.

[0091] Adding a composite lubricant to the surface layer improves the initial slippage of the film. The migration-resistant lubricant in the composite lubricant can provide some of the slippage without the need for a precipitation process. By adjusting the particle size range, it is possible to ensure that the heat-sealing and optical properties of the film are not affected. Furthermore, the amide-based lubricant in the surface layer can impart specific slippage, further reducing the film's coefficient of friction and improving the film's initial slippage. Meanwhile, the use of a composite lubricant and the matching of the lubricants in the inner and surface layers provide good high-temperature slippage and heat-sealing retention.

[0092] The resulting composite film may have a surface friction coefficient of less than 0.3, preferably 0.23 or less, and after heating at 60°C for 24 hours, the change in the surface friction coefficient of the film is 0.02 or less, preferably the change in the surface friction coefficient of the film is 0.01 or less.

[0093] Furthermore, an insulating additive can be added to the composite film of the present invention, thereby improving the electrical insulation of the propylene polymer composite film. Preferably, a grafted propylene polymer can be used as the insulating additive.

[0094] The grafted propylene polymer may be added to layer a and / or layer b. The grafted propylene polymer may be added in an amount of 5 to 45% by weight based on the total weight of each layer.

[0095] In a preferred embodiment, based on the total weight of layer a, layer a comprises 50 to 90 wt %, preferably 55 to 75 wt %, of homopolypropylene, 5 to 45 wt %, preferably 10 to 30 wt %, of grafted propylene polymer, and 2 to 40 wt %, preferably 5 to 20 wt %, of polyolefin elastomer; based on the total weight of layer b, layer b comprises 40 to 100 wt %, preferably 70 to 90 wt %, of propylene random copolymer, and 0 to 60 wt %, preferably 10 to 30 wt %, of polyolefin elastomer.

[0096] In another embodiment, based on the total weight of layer a, layer a comprises 50 to 100 wt%, preferably 75 to 95 wt%, of a propylene polymer and 0 to 50 wt%, preferably 5 to 25 wt%, of a polyolefin elastomer; based on the total weight of layer b, layer b comprises 50 to 90 wt%, preferably 60 to 85 wt%, of a propylene random copolymer, 5 to 40 wt%, preferably 5 to 20 wt%, of a polyolefin elastomer, and 2 to 40 wt%, preferably 5 to 20 wt%, of a grafted propylene polymer.

[0097] The grafted propylene polymer may comprise structural units derived from the copolypropylene and structural units derived from and grafted to the grafting monomer.

[0098] The grafting monomer may be selected from the group consisting of acrylates; acrylic acid; styrene; alkenyl-containing silanes; alkenyl-containing heterocyclic monomers; and combinations of anhydrides having at least one olefinic unsaturation and an alkenyl-containing polymerizable monomer.

[0099] The melt flow rate of the grafted propylene polymer under a load of 2.16 kg at 230°C may be 0.01 to 30 g / 10 min, preferably 0.05 to 20 g / 10 min, further preferably 0.1 to 10 g / 10 min, and further preferably 0.2 to 8 g / 10 min.

[0100] The copolypropylene may be a propylene copolymer containing ethylene or a higher α-olefin or a mixture thereof. Specifically, the comonomer of the copolypropylene is at least one selected from the group consisting of ethylene and a C4-C8 α-olefin. The C4-C8 α-olefin includes, but is not limited to, at least one of 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, and 1-octene. The comonomer is preferably ethylene and / or 1-butene, and more preferably, the copolypropylene consists of propylene and ethylene.

[0101] In addition to the compositional characteristics described above, the copolypropylene has at least one of the following characteristics: a comonomer content of 0.5 to 30 mol %, preferably 4 to 25 mol %; a xylene soluble content of 2 to 80 wt %, preferably 18 to 75 wt %, more preferably 30 to 70 wt %; a comonomer content of the solubles of 10 to 70 wt %, preferably 10 to 50 wt %, more preferably 20 to 35 wt %; a polypropylene having a comonomer content of 0.5 to 30 mol %, preferably 4 to 25 mol %; a polypropylene having a comonomer content of 0.5 to 30 mol %, preferably 4 to 25 mol %; a polypropylene having a comonomer content of 0.5 to 30 mol %, more ... the intrinsic viscosity ratio of the soluble matter is 0.3 to 5, preferably 0.5 to 3, and more preferably 0.8 to 1.3; the melt flow rate under a load of 2.16 kg at 230°C is 0.01 to 60 g / 10 min, preferably 0.05 to 35 g / 10 min, and more preferably 0.5 to 15 g / 10 min; the melting temperature (Tm) is greater than 100°C, preferably 110 to 180°C, and more preferably 120 to 170°C; and the weight average molecular weight is 20 × 10 4 ~60×10 4 g / mol.

[0102] The copolypropylene can be any suitable commercially available polypropylene powder, and can also be produced by common polymerization processes documented in the literature. For example, the copolypropylene can be prepared by referring to the processes described in CN101679557A and CN101058654A.

[0103] In one embodiment, the grafted propylene polymer may include structural units derived from the copolypropylene and structural units derived from acrylate monomers and optionally acrylic acid monomers grafted thereto. Based on the weight of the grafted propylene polymer, the content of the grafted structural units derived from the acrylate monomers and optional acrylic acid monomers may be 0.3 to 7 wt %, preferably 0.8 to 5 wt %. In the grafted propylene polymer, the molar ratio of the structural units derived from the acrylate monomers to the structural units derived from the acrylic acid monomers may be 1:0 to 2, preferably 1:0.125 to 1.

[0104] The acrylate monomer as the grafting monomer can be any monomeric acrylate compound capable of free radical polymerization, and can be at least one selected from the monomers having the structure shown in formula I: [ka] wherein R1, R2, and R3 are each independently selected from H, C1-C6 straight chain alkyl, and C3-C6 branched alkyl; and R4 is selected from the following substituted or unsubstituted groups: C1-C 20 Straight chain alkyl, C3-C 20 Branched alkyl, C3-C 12 Cycloalkyl, C3-C 12 Alkylene oxide groups, and C3-C 12 The alkylene oxide alkyl has at least one substituent selected from halogen, amino and hydroxyl.

[0105] Preferably, the acrylate monomer is at least one selected from the group consisting of methyl (meth)acrylate, sec-butyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, isooctyl (meth)acrylate, lauryl (meth)acrylate, cocolate (meth)acrylate, octadecyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, dimethylaminopropyl (meth)acrylate, and glycidyl (meth)acrylate.

[0106] The acrylic acid monomer can be any monomeric acrylic acid compound capable of free radical polymerization, and can be at least one selected from the monomers having the structure shown in formula II: [ka] In Formula II, R 1 , R 2 and R 3 are each independently selected from H, C1-C6 straight chain alkyl, and C3-C6 branched alkyl.

[0107] Preferably, the acrylic acid monomer is at least one selected from the group consisting of acrylic acid, methacrylic acid, and 2-ethylacrylic acid.

[0108] C3-C in the present invention 12 Alkylene oxide alkyl refers to an alkyl group substituted with an alkylene oxide group having 3 to 12 carbon atoms, such as oxiranylmethyl.

[0109] In the present invention, structural units derived from acrylic acid monomers may be absent or may be present together with structural units derived from acrylate monomers. Preferably, the molar ratio of structural units derived from acrylate monomers to structural units derived from acrylic acid monomers is 1:0-2, preferably 1:0.125-1.

[0110] The ratio of the total mass of the acrylate monomer and optional acrylic acid monomer to the mass of the copolypropylene is 0.1-10:100, preferably 0.5-8:100, more preferably 0.8-7:100. The molar ratio of the acrylate monomer to the acrylic acid monomer is 1:0-2, preferably 1:0.125-1.

[0111] In another embodiment, the grafted propylene polymer may contain structural units derived from copolypropylene and structural units derived from styrene monomers. Based on the weight of the grafted propylene polymer, the content of the grafted structural units derived from styrene monomers in the grafted propylene polymer may be 0.5 to 14 wt%, preferably 1 to 7.5 wt%, more preferably 1.5 to 5 wt%.

[0112] The styrene monomer as the grafting monomer may be any styrene compound capable of free radical polymerization, and may be at least one selected from the group consisting of a monomer having a structure represented by formula III, a monomer having a structure represented by formula IV, and a monomer having a structure represented by formula V; [ka] In Formula III, R 1 , R 2 and R 3 are each independently selected from H and substituted or unsubstituted C1-C6 alkyl; R 4 -R 8 are each independently H, halogen, hydroxyl, amino, phosphate, sulfonate, substituted or unsubstituted C-C 12Alkyl, substituted or unsubstituted C3-C 12 Cycloalkyl, substituted or unsubstituted C1-C 12 Alkoxy, substituted or unsubstituted C1-C 12 Ester groups, and substituted or unsubstituted C1-C 12 amine groups, and the substituents are selected from halogen, hydroxyl, amino, phosphate, sulfonate, C1-C 12 Alkyl, C3-C 12 Cycloalkyl, C1-C 12 Alkoxy groups, C1-C 12 Ester groups, and C1-C 12 amine groups; preferably R 1 , R 2 and R 3 are each independently selected from H and substituted or unsubstituted C1-C3 alkyl; R 4 -R 8 are each independently selected from H, halogen, hydroxyl, amino, substituted or unsubstituted C1-C6 alkyl, and substituted or unsubstituted C1-C6 alkoxy; [ka] In Formula IV, R1, R2, and R3 are each independently selected from H and substituted or unsubstituted C1-C6 alkyl; R4-R 10 are each independently H, halogen, hydroxyl, amino, phosphate, sulfonate, substituted or unsubstituted C-C 12 Alkyl, substituted or unsubstituted C3-C 12 Cycloalkyl, substituted or unsubstituted C1-C 12 Alkoxy, substituted or unsubstituted C1-C 12 Ester groups, and substituted or unsubstituted C1-C 12 amine groups, and the substituents are selected from halogen, hydroxyl, amino, phosphate, sulfonate, C1-C 12 Alkyl, C3-C 12 Cycloalkyl, C1-C 12 Alkoxy groups, C1-C 12 Ester groups, and C1-C 12amine groups; preferably R1, R2 and R3 are each independently selected from H and substituted or unsubstituted C1-C3 alkyl, and R4-R 10 are each independently selected from H, halogen, hydroxyl, amino, substituted or unsubstituted C1-C6 alkyl, and substituted or unsubstituted C1-C6 alkoxy; the substituents are selected from halogen, hydroxyl, amino, C1-C6 alkyl, and C1-C6 alkoxy; [ka] In Formula V, R1', R2', and R3' are each independently selected from H and substituted or unsubstituted C1-C6 alkyl; R4'-R 10 ' are each independently H, halogen, hydroxyl, amino, phosphate, sulfonate, substituted or unsubstituted C1-C 12 Alkyl, substituted or unsubstituted C3-C 12 Cycloalkyl, substituted or unsubstituted C1-C 12 Alkoxy, substituted or unsubstituted C1-C 12 Ester groups, and substituted or unsubstituted C1-C 12 amine groups, and the substituents are selected from halogen, hydroxyl, amino, phosphate, sulfonate, C1-C 12 Alkyl, C3-C 12 Cycloalkyl, C1-C 12 Alkoxy groups, C1-C 12 Ester groups, and C1-C 12 amine groups; preferably R1', R2' and R3' are each independently selected from H and substituted or unsubstituted C1-C3 alkyl, and R4'-R 10 are each independently selected from H, halogen, hydroxyl, amino, substituted or unsubstituted C1-C6 alkyl, and substituted or unsubstituted C1-C6 alkoxy; the substituents are selected from halogen, hydroxyl, amino, C1-C6 alkyl, and C1-C6 alkoxy.

[0113] Preferably, the styrene monomer may be at least one selected from the group consisting of styrene, α-methylstyrene, 1-vinylnaphthalene, 2-vinylnaphthalene, mono- or poly-substituted styrene, mono- or poly-substituted α-methylstyrene, mono- or poly-substituted 1-vinylnaphthalene, and mono- or poly-substituted 2-vinylnaphthalene; the substituent is preferably at least one selected from the group consisting of halogen, hydroxyl, amino, phosphate group, sulfonate group, C1-C8 straight chain alkyl, C3-C8 branched alkyl or cycloalkyl, C1-C6 straight chain alkoxy, C3-C8 branched alkoxy or cyclic alkoxy, C1-C8 straight chain ester group, C3-C8 branched ester group or cyclic ester group, C1-C8 straight chain amine group, and C3-C8 branched amine group or cyclic amine group.

[0114] More preferably, the styrene monomer is at least one selected from the group consisting of styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, and 4-methylstyrene.

[0115] The mass ratio of the styrene monomer to the copolypropylene may be 0.5 to 16:100, preferably 1 to 12:100, and more preferably 2 to 10:100.

[0116] In another embodiment, the grafted propylene polymer (b) comprises structural units derived from the copolypropylene and structural units derived from the alkenyl-containing silane monomer. Based on the weight of the grafted propylene polymer (b), the content of the grafted structural units derived from the alkenyl-containing silane monomer in the grafted propylene polymer (b) may be 0.2 to 6 wt %, preferably 0.2 to 2.5 wt %.

[0117] The alkenyl-containing silane monomer as the grafting monomer can be any monomeric silane compound capable of free radical polymerization, and the alkenyl-containing silane monomer can be at least one selected from the monomers having the structure shown in Formula VI: [ka] In Formula VI, R1 is C2-C 12 alkenyl, preferably monounsaturated alkenyl; R2, R3 and R4 are each independently substituted or unsubstituted C1-C 12 Straight chain alkyl, substituted or unsubstituted C3-C 12 Branched alkyl, substituted or unsubstituted C1-C 12 Alkoxy, and substituted or unsubstituted C-C 12 Preferably, R1 is a C2-C6 alkenyl, preferably a monounsaturated alkenyl; R2, R3, and R4 are each independently selected from substituted or unsubstituted C1-C6 straight-chain alkyl, substituted or unsubstituted C3-C6 branched alkyl, substituted or unsubstituted C1-C6 alkoxy, and substituted or unsubstituted C1-C6 acyloxy.

[0118] More preferably, the alkenyl-containing silane monomer is at least one selected from the group consisting of vinyltriethoxysilane, vinyltrimethoxysilane, vinyltriisopropoxysilane, vinyltri-tert-butoxysilane, vinyltriacetoxysilane, methylvinyldimethoxysilane, ethylvinyldiethoxysilane, allyltriethoxysilane, allyltrimethoxysilane, allyltriisopropoxysilane, vinyltris(β-methoxyethoxy)silane, allyltris(β-methoxyethoxy)silane, allyltri-tert-butoxysilane, allyltriacetoxysilane, methylallyldimethoxysilane, and ethylallyldiethoxysilane.

[0119] The weight ratio of the alkenyl-containing silane monomer to the copolypropylene may be 0.5 to 12:100, preferably 0.8 to 9:100, and more preferably 1 to 6:100.

[0120] In another embodiment, the graft propylene polymer comprises structural units derived from copolypropylene, structural units derived from anhydride monomers, and structural units derived from alkenyl-containing polymerizable monomers. The alkenyl-containing polymerizable monomer may be at least one selected from the group consisting of vinyl acetate, styrene, α-methylstyrene, (meth)acrylate, vinyl alkyl ether, vinylpyrrolidone, vinylpyridine, vinylimidazole, and acrylonitrile. The anhydride is preferably selected from maleic anhydride and / or itaconic anhydride. The content of the graft structural units derived from the anhydride monomer and the alkenyl-containing polymerizable monomer may be 0.1 to 5 wt%, preferably 0.4 to 3 wt%. The content of the graft structural units derived from the anhydride monomer may be 0.05 to 2 wt%, preferably 0.2 to 0.7 wt%. The molar ratio of the structural units derived from the anhydride monomer to the structural units derived from the alkenyl-containing polymerizable monomer may be 1:1 to 20, preferably 1:1 to 10. The alkenyl-containing polymerizable monomer as the graft monomer is preferably at least one selected from monomers having a structure represented by formula 1. [ka] In Formula 1, R1, R2, and R3 are each independently selected from H and substituted or unsubstituted alkyl; and R4 is selected from substituted or unsubstituted alkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted aryl, substituted or unsubstituted ester groups, substituted or unsubstituted carboxyl, substituted or unsubstituted cycloalkyl or heterocyclic groups, and cyano groups.

[0121] Preferably, R1, R2 and R3 are each independently selected from H and substituted or unsubstituted C1-C6 alkyl, more preferably R1, R2 and R3 are each independently selected from H and substituted or unsubstituted C1-C3 alkyl; R4 is substituted or unsubstituted C1-C 20 Alkyl, substituted or unsubstituted C1-C 20 Alkoxy, substituted or unsubstituted C6-C20 Aryl, substituted or unsubstituted C1-C 20 Ester groups, substituted or unsubstituted C1-C 20 Carboxylic acid group, substituted or unsubstituted C3-C 20 R is selected from substituted or unsubstituted C-C alkyl, cycloalkyl, or heterocyclic groups, and cyano groups, and the substituents are selected from halogen, hydroxyl, amino, C-C alkyl, and C-C cycloalkyl; preferably, R is substituted or unsubstituted C-C 12 Alkyl, substituted or unsubstituted C1-C 18 Alkoxy, substituted or unsubstituted C6-C 12 Aryl, substituted or unsubstituted C1-C 12 Ester groups, substituted or unsubstituted C1-C 12 Carboxylic acid group, substituted or unsubstituted C3-C 12 R is selected from cycloalkyl or heterocyclic groups, and cyano groups, and the substituents are selected from halogen, C1-C6 alkyl and C3-C6 cycloalkyl; more preferably, R is substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C1-C6 alkyl, 12 The heterocyclic group is preferably selected from alkoxy, substituted or unsubstituted C6-C8 aryl, substituted or unsubstituted C1-C6 ester group, substituted or unsubstituted C1-C6 carboxylic acid group, substituted or unsubstituted C3-C6 cycloalkyl or heterocyclic group, and cyano group. Particularly preferably, the heterocyclic group is selected from imidazolyl, pyrazolyl, carbazolyl, pyrrolidinone group, pyridyl, piperidinyl, caprolactam group, pyrazinyl, thiazolyl, purinyl, morpholinyl, and oxazolinyl.

[0122] More preferably, R1, R2 and R3 are each independently selected from H and substituted or unsubstituted C1-C6 alkyl; and R4 is selected from a group represented by formula 2, a group represented by formula 3, a group represented by formula 4, a group represented by formula 5, a combination of a group represented by formula 5 and a group represented by formula 6, and a heterocyclic group. [ka] In Equation 2, R 4 -R 8are each independently H, halogen, hydroxyl, amino, phosphate, sulfonate, substituted or unsubstituted C-C 12 Alkyl, substituted or unsubstituted C3-C 12 Cycloalkyl, substituted or unsubstituted C1-C 12 Alkoxy, substituted or unsubstituted C1-C 12 Ester groups, and substituted or unsubstituted C1-C 12 amine groups, and the substituents are selected from halogen, hydroxyl, amino, phosphate, sulfonate, C1-C 12 Alkyl, C3-C 12 Cycloalkyl, C1-C 12 Alkoxy, C1-C 12 Ester groups, and C1-C 12 amine groups; preferably R 4 -R 8 are each independently selected from H, halogen, hydroxyl, amino, substituted or unsubstituted C1-C6 alkyl, and substituted or unsubstituted C1-C6 alkoxy. [ka] In formula 3, R4-R 10 are each independently H, halogen, hydroxyl, amino, phosphate, sulfonate, substituted or unsubstituted C-C 12 Alkyl, substituted or unsubstituted C3-C 12 Cycloalkyl, substituted or unsubstituted C1-C 12 Alkoxy, substituted or unsubstituted C1-C 12 Ester groups, and substituted or unsubstituted C1-C 12 amine groups, and the substituents are selected from halogen, hydroxyl, amino, phosphate, sulfonate, C1-C 12 Alkyl, C3-C 12 Cycloalkyl, C1-C 12 Alkoxy, C1-C 12 Ester groups, and C1-C 12 amine groups; preferably R-R 10are each independently selected from H, halogen, hydroxyl, amino, substituted or unsubstituted C1-C6 alkyl, and substituted or unsubstituted C1-C6 alkoxy, wherein the substituents are selected from halogen, hydroxyl, amino, C1-C6 alkyl, and C1-C6 alkoxy. [ka] In Formula 4, R4'-R 10 ' are each independently H, halogen, hydroxyl, amino, phosphate, sulfonate, substituted or unsubstituted C1-C 12 Alkyl, substituted or unsubstituted C3-C 12 Cycloalkyl, substituted or unsubstituted C1-C 12 Alkoxy, substituted or unsubstituted C1-C 12 Ester groups, and substituted or unsubstituted C1-C 12 amine groups, and the substituents are selected from halogen, hydroxyl, amino, phosphate, sulfonate, C1-C 12 Alkyl, C3-C 12 Cycloalkyl, C1-C 12 Alkoxy, C1-C 12 Ester groups, and C1-C 12 amine groups; preferably R4'-R 10 are each independently selected from H, halogen, hydroxyl, amino, substituted or unsubstituted C1-C6 alkyl, and substituted or unsubstituted C1-C6 alkoxy, wherein the substituents are selected from halogen, hydroxyl, amino, C1-C6 alkyl, and C1-C6 alkoxy. [ka] [ka] In Equation 5, R m is selected from the following substituted or unsubstituted groups: C-C 20 Straight chain alkyl, C3-C 20 Branched alkyl, C3-C 12Cycloalkyl, C3-C 12 Alkylene oxide groups, and C3-C 12 The alkylene oxide alkyl has at least one substituent selected from halogen, amino and hydroxyl.

[0123] More preferably, the alkenyl-containing polymerizable monomer is at least one selected from the group consisting of vinyl acetate, styrene, α-methylstyrene, (meth)acrylate, vinyl alkyl ether, vinylpyrrolidone, vinylpyridine, vinylimidazole, and acrylonitrile. The (meth)acrylate is preferably at least one selected from the group consisting of methyl (meth)acrylate, ethyl (meth)acrylate, and glycidyl (meth)acrylate. Preferably, the alkenyl-containing polymerizable monomer is selected from the group consisting of vinyl acetate, styrene, and α-methylstyrene. More preferably, the alkenyl-containing polymerizable monomer is styrene.

[0124] In the anhydride group-containing grafted propylene polymer, the molar ratio of structural units derived from (maleic) anhydride monomers to structural units derived from alkenyl-containing polymerizable monomers can be 1:1-20, preferably 1:1-10.

[0125] The anhydride may be selected from anhydrides having at least one olefinic unsaturation, more preferably the anhydride is selected from maleic anhydride and / or itaconic anhydride, even more preferably the anhydride is maleic anhydride.

[0126] The ratio of the total mass of the anhydride monomer and the alkenyl-containing polymerizable monomer to the mass of the copolypropylene can be 0.1 to 8: 100, preferably 0.3 to 5: 100. The mass of the anhydride monomer can be 5 to 100% by weight, preferably 10 to 100% by weight, of the mass of the alkenyl-containing polymerizable monomer.

[0127] In another embodiment, the grafted propylene polymer comprises structural units derived from the copolypropylene and structural units derived from the alkenyl-containing heterocyclic monomer. Based on the weight of the grafted propylene polymer, the content of the grafted structural units derived from the alkenyl-containing heterocyclic monomer may be 0.5 to 6 wt%, preferably 0.5 to 4 wt%.

[0128] The alkenyl-containing heterocyclic monomer as a grafting monomer may be any alkenyl-containing heterocyclic compound capable of free radical polymerization, and may be at least one selected from the group consisting of alkenyl-substituted imidazole, alkenyl-substituted pyrazole, alkenyl-substituted carbazole, alkenyl-substituted pyrrolidone, alkenyl-substituted pyridine or pyridinium salt, alkenyl-substituted piperidine, alkenyl-substituted caprolactam, alkenyl-substituted pyrazine, alkenyl-substituted thiazole, alkenyl-substituted purine, alkenyl-substituted morpholine, and alkenyl-substituted oxazoline. Preferably, the alkenyl-containing heterocyclic monomer is a monoalkenyl-containing heterocyclic monomer.

[0129] Specifically, the alkenyl-containing heterocyclic monomer may be at least one selected from the group consisting of 1-vinylimidazole, 2-methyl-1-vinylimidazole, N-allylimidazole, 1-vinylpyrazole, 3-methyl-1-vinylpyrazole, vinylcarbazole, N-vinylpyrrolidone, 2-vinylpyridine, 3-vinylpyridine, 4-vinylpyridine, 2-methyl-5-vinylpyridine, vinylpyridine-N-oxide, vinylpyridinium salt, vinylpiperidine, N-vinylcaprolactam, 2-vinylpyrazine, N-vinylpiperazine, 4-methyl-5-vinylthiazole, N-vinylpurine, vinylmorpholine, and vinyloxazoline.

[0130] The mass ratio of the alkenyl-containing heterocyclic monomer to the copolypropylene may be 0.3-12:100, preferably 0.5-10:100.

[0131] The grafting reaction described herein is a free radical polymerization reaction through which the grafting monomer forms a covalent bond (graft) with the copolypropylene.

[0132] Preferably, the grafted propylene polymer can be prepared from copolypropylene and graft monomers via a solid-phase grafting reaction, for example, according to the methods described in Chinese Patent Application Nos. 202011195771.2, 202011191001.0, 202011195799.6, 202011190917.4 and 202011195819.X.

[0133] Specifically, it can be prepared by a method comprising the following steps: subjecting a reaction mixture containing a copolypropylene and a grafting monomer to a solid-phase grafting reaction in the presence of an inert gas to obtain a grafted propylene polymer.

[0134] The solid-phase grafting reaction can be carried out by various conventional methods in the art, such as forming active grafting sites on the copolypropylene in the presence of a grafting monomer, or by forming active grafting sites on the copolypropylene and then treating it with a monomer for grafting. The grafting sites can be formed by treatment with a free radical initiator or by high-energy ionizing radiation or microwave treatment. Free radicals generated in the polymer as a result of chemical or radiation treatment form grafting sites on the polymer, and monomer polymerization is initiated at these sites.

[0135] Preferably, the grafting sites are initiated by a free radical initiator and the grafting reaction is further carried out, in which case the reaction mixture further comprises a free radical initiator, more preferably the free radical initiator is selected from a peroxide free radical initiator and / or an azo free radical initiator.

[0136] Among these, the peroxide free radical initiator is preferably at least one selected from the group consisting of dibenzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, lauroyl peroxide, dilauroyl peroxide, tert-butyl peroxybenzoate, diisopropyl peroxydicarbonate, tert-butyl peroxy(2-ethylhexanoate), and dicyclohexyl peroxydicarbonate.The azo free radical initiator is preferably azobisisobutyronitrile and / or azobisisoheptanonitrile.

[0137] More preferably, the grafting sites are initiated with a hydrogen peroxide free radical initiator and the grafting reaction is further carried out.

[0138] Additionally, the grafting reaction can also be carried out by the methods described in CN106543369A, CN104499281A, CN102108112A, CN109251270A, CN1884326A and CN101492517B.

[0139] The ratio of the mass of the free radical initiator to the total mass of the monomers for grafting may be 0.1-10:100, preferably 0.5-5:100.

[0140] The temperature of the grafting reaction may be 30 to 130°C, preferably 60 to 120°C, and the time may be 0.5 to 10 hours, preferably 1 to 5 hours.

[0141] "Reaction mixture" includes all materials added to the grafting reaction, which materials may be added all at once or at different stages of the reaction.

[0142] The reaction mixture may also contain a dispersant (preferably water or an aqueous solution of sodium chloride). The mass of the dispersant is preferably 50 to 300% of the mass of the copolypropylene.

[0143] The reaction mixture may contain an interfacial agent. The interfacial agent is an organic solvent that has a swelling effect on polyolefins, preferably at least one of the following organic solvents that have a swelling effect on copolypropylene: ether solvents, ketone solvents, aromatic hydrocarbon solvents, and alkane solvents. More preferably, the interfacial agent is at least one of the following organic solvents: chlorinated benzenes, polychlorinated benzenes, alkanes or cycloalkanes with carbon atoms of 6 or more, benzene, C1-C4 alkyl-substituted benzenes, C2-C6 aliphatic ethers, C3-C6 aliphatic ketones, and decahydronaphthalene. Even more preferably, the interfacial agent is at least one of the following organic solvents: benzene, toluene, xylene, chlorobenzene, tetrahydrofuran, diethyl ether, acetone, hexane, cyclohexane, decahydronaphthalene, and heptane. The mass content of the interfacial agent is preferably 1 to 35%, more preferably 10 to 25%, of the mass of the copolypropylene.

[0144] The reaction mixture may further contain an organic solvent to dissolve the solid free radical initiator, preferably at least one of a C2-C5 alcohol, a C2-C4 ether, and a C3-C5 ketone, more preferably at least one of a C2-C4 alcohol, a C2-C3 ether, and a C3-C5 ketone, and most preferably at least one of ethanol, diethyl ether, and acetone. The mass content of the organic solvent is preferably 1 to 35% of the mass of the copolypropylene.

[0145] During the grafting reaction, the grafting monomers can be polymerized individually or with each other to the non-grafted polymer in a certain amount. Therefore, the grafted propylene polymer can include not only the product (crude product) directly prepared from the copolypropylene and the grafting monomers through the grafting reaction, but also the pure graft-modified polypropylene product obtained by further purifying the product. Therefore, the preparation method may optionally include a step of purifying the crude product. The purification can be performed by various conventional methods in the art (e.g., extraction).

[0146] Preferably, the grafting efficiency of the grafting reaction is controlled to 5 to 100%, preferably 30 to 100%, more preferably 25 to 80%, or 35 to 60%. The concept of grafting efficiency is well known to those skilled in the art and refers to (amount of grafted graft monomer) / (total amount of graft monomer in the reaction feed).

[0147] The inert gas may be any of a variety of inert gases commonly used in the art, including, but not limited to, nitrogen and argon.

[0148] <Layer structure and properties of composite film> The composite film of the present invention may be composed of only layer a and layer b, that is, a two-layer film.

[0149] In an alternative embodiment, in addition to layers a and b, the composite film of the present invention may include one or more additional layers, i.e., three or more layers, thereby forming a three-layer film or a film with more than three layers, with layer b being a surface layer of the composite film. The composition of the additional layer may be the same as or different from that of layers a or b. This layer may also be formed by mixing the components of layer a with the components of layer b. For example, if the composite film is a three-layer film, the additional layer is referred to as layer c, with layers b and c located on either side of layer a, i.e., layer c is located on the side of layer a opposite to layer b, and layer c is also a surface layer. If the composite film is five layers, two layers b may be used as upper and lower surface layers, two layers c may be used as middle layers, and one layer a may be used as a core layer.

[0150] The thicknesses of Layer a, Layer b, and optional Layer c and additional layers in the present invention are not particularly limited. The ratio of the total thickness of layers other than Layer a to the thickness of Layer a can be 1:6 to 2:1, for example, 1:5.5, 1:5, 1:4.5, 1:4, 1:3.5, 1:3, 1:2.5, 1:2, 1:1.5, 1:1, 1.5:1, and any value therebetween, preferably 1:4 to 2:1, more preferably 1:4 to 2:1. Such composite films advantageously have better mechanical properties (e.g., tensile strength) and more stable properties.

[0151] It has been unexpectedly found that since the composite film of the present invention contains band-like rubber phases dispersed from the propylene impact copolymer arranged parallel to each other, the composite film of the present invention can simultaneously have excellent impact resistance and optical properties, or further have excellent mechanical properties (e.g., tensile strength) and / or excellent heat seal performance, and can have good heat seal strength at a lower heat seal temperature.

[0152] When homopolypropylene and polyolefin elastomer are further present in the composite film of the present invention in addition to the rubber phase from the propylene impact copolymer, the rubber phase and non-elastic moieties in the propylene impact copolymer interact synergistically with the polymer spherules formed by the homopolypropylene and the polyolefin elastomer rubber phase, thereby enabling the impact resistance and optical properties of the composite film to be further improved simultaneously, or further improving its mechanical properties.

[0153] The composite films of the present invention may advantageously have one or more of the following properties, preferably all of the following properties: 1) a pendulum impact strength of 0.4 J or more (e.g., 0.5 J, 0.6 J, or 0.7 J or more), preferably 0.9 J or more, more preferably 1.1 J or more (e.g., 1.5 J or more), or even 1.8 J or more; 2) the film haze is less than 7%, preferably 5% or less, more preferably 3% or less (e.g., 2.5% or less), and even more preferably 2% or less; 3) The tensile strength in the machine direction (MD) is 40 MPa or more, preferably 50 MPa or more; 4) A heat seal strength at 150°C of 12 N / 15 mm or more, preferably 15 N / 15 mm or more, preferably 17 N / 15 mm or more, more preferably 18 N / 15 mm or more, or even 19 N / 15 mm or more (e.g., 20 N / 15 mm or more); 5) The thickness deviation in the MD direction is 1.3 or less (for example, 1.0 or less), preferably 0.5 or less; 6) The thickness deviation in the TD direction is 1.5 or less (e.g., 1.3 or less), preferably 0.75 or less or 0.8 or less; 7) The deviation of impact resistance in the MD direction is 0.05 or less, preferably 0.03 or less; 8) The deviation of impact resistance in the TD direction is 0.07 or less, preferably 0.05 or less, and more preferably 0.04 or less; 9) Surface energy is 29 mN / m or more (e.g., 33 mN / m or more, 34.5 mN / m or more), preferably 35 mN / m or more; 10) Volume resistivity is 1.5 x 10 15 Ω·m or more, preferably 2.0×10 15 Ω·m or more.

[0154] The measurement methods and standards for the characteristics are as follows: <Pendulum impact strength> Complies with standard GB / T 8809-2015.

[0155] <Film haze> Complies with standard GB / T 2410-2008.

[0156] <Tensile strength> Along the machine direction of the film, conforms to standard GB / T1040.3-2006.

[0157] <Heat seal strength> Compliant with standard QB / T2358, heat seal temperature 150°C, heat seal pressure 0.2MPa, heat seal time during sample preparation 3 seconds.

[0158] <Thickness deviation in the MD direction> The thickness of the film is measured using a thickness gauge of model 7301 from Mitutoyo Corporation of Japan. As shown in Figure 1a, after trimming the edge of the film, one point is taken every 1 meter along the MD direction on the center line of the film, a total of 10 points are taken, and the thickness at each point is measured in accordance with the method specified in GB / T8809-2015. The average value is taken as the thickness of the film (MD). Then, based on the above data, the standard deviation of the thickness is calculated as the thickness deviation in the MD direction.

[0159] <Thickness deviation in the TD direction> As shown in Figure 1b, 10 points are evenly taken along the TD direction of an arbitrary part of the film, the thickness at each point is measured in accordance with the method specified in GB / T8809-2015, and the average value is taken as the film thickness (TD). Then, based on the above data, the standard deviation of the thickness is calculated as the thickness deviation in the TD direction.

[0160] <Impact strength deviation in the MD direction> As shown in Figure 1a, after trimming the edge of the film, one point is taken every 1 meter along the MD direction on the center line of the film, a total of 10 points are taken, and the impact strength at each point is measured in accordance with the method specified in GB / T8809-2015. The average value is taken as the impact strength of the film (MD). Then, based on the above data, the standard deviation of the impact strength is calculated as the impact strength deviation in the MD direction.

[0161] <Impact strength deviation in the TD direction> As shown in Figure 1b, 10 points are evenly taken along the TD direction of an arbitrary part of the film, the impact strength at each point is measured in accordance with the method specified in GB / T8809-2015, and the average value is taken as the impact strength of the film (TD). Then, based on the above data, the standard deviation of the impact strength is calculated as the impact strength deviation in the TD direction.

[0162] <Surface energy of the film> It is measured in accordance with the method specified in GB / T14216-2008.

[0163] <Volume resistivity> It is measured in accordance with the method specified in GB / T1410-2006.

[0164] (Preparation of Composite Films) According to a second aspect, the present invention provides a method for preparing the composite film of the present invention, the method comprising the step of extrusion casting a raw material composition for forming each layer to form the composite film.

[0165] According to the present invention, before the extrusion process, the elastic portion of the propylene impact copolymer used in the raw composition can form a granular rubber phase, and the average particle size of the rubber phase is 1.8 μm or less, preferably 1.5 μm or less, and the maximum particle size measured by observing the cross section of a test piece with an SEM is 2.5 μm or less, preferably 2 μm or less.

[0166] The rubber phase is generally spherical or nearly spherical.

[0167] In this specification, spherical and nearly spherical mean that the aspect ratio is substantially 1 to 2. "Substantially" means that at least 90% of the rubber phase particles have an aspect ratio of 1 to 2.

[0168] The average particle size and maximum particle size of the rubber phase in the propylene impact copolymer in the raw material were measured by observing the cross section of an impact test specimen using a scanning electron microscope (SEM). The impact test specimen was prepared in accordance with the method specified in standard GB / T8809-2015. For spherical particles, the particle diameter was measured, and for nearly spherical particles, the longitudinal axis of the particle (the distance between the two furthest points on the particle outline) was measured. The average particle size was determined by observing the SEM photographs for 50 sample points, and the maximum particle size was determined by the maximum size at the sample points.

[0169] According to the present invention, by controlling the size of the rubber phase in the raw propylene impact copolymer, the size of the rubber phase in the composite film can be made to fall within the specific range of the present invention.

[0170] Prior to the extrusion process, the various components of the polymer composition used as raw materials for preparing each layer (including optional additives such as antioxidants, lubricants and other film additives) may be mixed or blended and optionally pelletized.

[0171] The pelletization process can be carried out by uniformly mixing the various components of propylene polymer composition A for layer a and propylene polymer composition B for layer b, and optionally polymer compositions for additional layers, together with any additives, in a high-speed mixer, adding this uniformly mixed material to a twin-screw extruder for melt mixing, homogeneously extruding and pelletizing, and drying to obtain pellets. The processing temperature of the twin-screw extruder can be controlled to 170 to 230°C.

[0172] The resulting pellets are then subjected to extrusion casting to prepare a composite film. The extrusion casting process of the pellets can be carried out in a conventional manner using common equipment. The extrusion casting method may include feeding pellets of the polymer compositions used to prepare the various layers into multiple extruders, respectively, and co-extruding, mixing, and flowing the pellets through the extruder dies, followed by casting onto a roll, drawing off the roll, trimming, and winding in sequence to prepare a composite film. The extrusion casting temperature may be controlled at 170 to 230°C. The temperature of the casting roll may be 10 to 50°C.

[0173] According to the preparation method of the present invention, the rubber phase contained in the propylene impact copolymer as a raw material is deformed from a spherical or nearly spherical shape to a band-like shape during the composite film preparation process and oriented along a certain direction, i.e., parallel orientation. By maintaining this microstructure in the final composite film product, a composite film of the present invention having good impact resistance and optical properties can be obtained.

[0174] Advantageously, the polyolefin elastomer used is also deformed during the process of preparing the composite film into a band-like rubber phase and oriented along a certain direction, i.e., parallel, so as to maintain the above-mentioned microstructure in the final composite film product, and at the same time, it synergistically interacts with the rubber phase of the propylene impact copolymer to further improve the impact resistance and optical properties as well as other properties (mechanical properties, heat-sealing properties, film uniformity, etc.) of the composite film.

[0175] The resulting composite film can be stretched (eg, biaxially stretched) in a subsequent process, which can advantageously further improve the mechanical properties of the composite film.

[0176] According to some embodiments of the present invention, a method for preparing a composite film includes the steps of pelletizing propylene polymer composition A and propylene polymer composition B, followed by extrusion casting and stretching to obtain a composite film.

[0177] (Use of composite film) According to a third aspect, the present invention provides the use of the composite film of the present invention in the field of packaging materials.

[0178] The composite film of the present invention can simultaneously have good impact resistance and optical properties, even better tensile properties, and / or can have heat seal strength at a lower heat seal temperature, and can also have good thickness and / or property uniformity, so the composite film of the present invention can be particularly used in fields that require both impact resistance and optical properties of the film, such as high-end packaging fields such as battery packaging materials, electronic product packaging, high-end food packaging, and other fields. The packaging material may, for example, include an aluminum-plastic composite film.

[0179] When using the composite film of the present invention, layer a is used as a core layer (i.e., a layer relatively far away from the medium with which the composite film comes into contact), and layer b is used as a surface layer (i.e., a layer close to the medium with which the composite film comes into contact), such as an electrolyte with which the battery packaging material comes into contact.

[0180] Therefore, according to a fourth aspect, the present invention provides a packaging material comprising the composite film of the present invention. The packaging material can be, for example, a battery packaging material, an electronic product packaging material, or a food packaging material, particularly a high-end food packaging material. The packaging material can, for example, comprise an aluminum-plastic composite film.

[0181] [Example] The present invention will be explained in more detail below by way of examples, but the scope of the present invention is not limited to these examples.

[0182] Examples and comparative examples are shown below.

[0183] A model LCR400 film casting machine was available from Labtech, Sweden.

[0184] The properties of the raw materials, polymer compositions and films were measured according to the following methods.

[0185] (1) Melt flow rate (MFR) The measurement was carried out in accordance with the method specified in GB / T3682-2000, the test temperature was 230°C, and the load was 2.16 kg.

[0186] (2) Tensile strength of the film Measurement was performed in accordance with the method specified in GB / T1040.3-2006.

[0187] (3) Calculation of film pendulum impact strength and impact strength deviation The measurement was performed in accordance with the method specified in GB / T8809-2015. Specifically, as shown in Figure 1a, after trimming the edges of the film, one point was taken every 1 m along the center line of the film in the MD direction, for a total of 10 points, and the impact strength at each point was measured in accordance with the method specified in GB / T8809-2015. The average value was taken as the impact strength (MD) of the film, and the standard deviation of the impact strength was calculated based on the above data.

[0188] As shown in Figure 1b, 10 points were uniformly taken along the TD direction of any part of the film, and the impact strength at each point was measured in accordance with the method specified in GB / T8809-2015. The average value was taken as the impact strength (TD) of the film, and the standard deviation of the impact strength was calculated as the impact strength deviation in the TD direction based on the above data.

[0189] (4) Film haze Measurement was performed in accordance with the method specified in GB / T2410-2008.

[0190] (5) Heat seal strength of film Measurement was performed in accordance with the method specified in QB / T2358. The heat sealing temperature during sample preparation was 150°C, the heat sealing pressure was 0.2 MPa, and the heat sealing time was 3 seconds.

[0191] (6) Isotacticity 13The nuclear magnetic carbon spectrum of the propylene polymer was measured at 400 MHz using a Bruker AVANCE III nuclear magnetic resonance spectrometer (NMR). 13 C-NMR was measured using deuterated o-dichlorobenzene as the solvent, with a sample concentration of 250 mg sample / 2.5 mL solvent. To prevent oxidative degradation of the sample during dissolution and data collection, 2 mg of the antioxidant 2,6-di-tert-butyl-4-methylphenol (abbreviated as BHT) was added to the sample. The test sample was dissolved at 140 °C. 13 C-NMR was collected at 125°C, with a probe specification of 10 mm, 90° pulse, sampling time AQ of 5 seconds, delay time D1 of 1 second, and scan number of 6000. The isotactic dyad [mm] content was used as the isotacticity.

[0192] (7) Molecular weight distribution (Mw / Mn) The measurement was performed by gel permeation chromatography (GPC). A model PL-GPC220 gel permeation chromatograph manufactured by Polymer Laboratories, UK, was used, coupled with an IR5 infrared detector. The chromatography column in the gel permeation chromatography consisted of three 10 μm Pligel MIXED-B columns connected in series. The solvent and mobile phase were both 1,2,4-trichlorobenzene (containing 0.3 g / 1000 mL of antioxidant 2,6-di-tert-butyl-p-cresol), the column temperature was 150 °C, and the flow rate was 1.0 mL / min. EasiCal PS-1 narrow-distribution polystyrene standard manufactured by PL was used for universal calibration.

[0193] (8) Film thickness and thickness deviation test The film thickness was measured using a Mitutoyo Model 7301 thickness gauge from Japan. After trimming the film edges, a total of 10 points were measured along the centerline of the film, one every meter along the MD, as shown in Figure 1a. The thickness at each point was measured according to the method specified in GB / T 8809-2015, and the average value was used as the film thickness (MD). Based on the above data, the standard deviation of thickness was calculated as the thickness deviation in the MD.

[0194] As shown in Figure 1b, 10 points were uniformly selected along the TD direction of any part of the film, and the thickness at each point was measured according to the method specified in GB / T8809-2015, and the average value was taken as the film thickness (TD). Based on the above data, the standard deviation of the thickness was calculated as the thickness deviation in the TD direction.

[0195] (9) Calculation of standard deviation (S) It was calculated according to formula (a).

number

number

[0196] (10) Measurement of shear viscosity The measurements were performed using a Rheograph 25 capillary rheometer manufactured by GOTTFERT, Germany, in accordance with the method described in ISO 11443:2014. The settings were as follows: capillary rheometer temperature 230 °C, die capillary length 30 mm, capillary aspect ratio 30:1, and preheating time 300 s; -1 and 640s -1 Shear rate (

number

number

[0197] Shear rate 160 s -1 and 640s -1 The shear viscosity of the propylene polymer composition A in the examples and comparative examples is ηA 160 and ηA 640 Shear rate 160 s -1 and 640s -1 The shear viscosity of the propylene polymer composition B is ηB 160 and ηB 640 P is the shear rate of 160 r between propylene polymer composition A and propylene polymer composition B. -1 The difference in shear viscosity (ηA 160 -ηB 160 ) of 640r -1 The difference in shear viscosity (ηA 640 -ηB 640 ) to the ratio (ηA 160 -ηB 160 ) / (ηA 640 -ηB 640 )

[0198] (11) Atomic force microscope (AFM) photograph The transverse cut cross-sections of the film samples were scanned and observed using a Dimension FastScan Icon atomic force microscope (Bruker, USA) in quantitative nanomechanical scanning mode.

[0199] (12) Lateral size of film and aspect ratio of rubber phase Using a Bruker Dimension FastScan Icon atomic force microscope (USA), the horizontal cross section of the film sample was scanned and observed in quantitative nanomechanical scanning mode. The horizontal axis (the length between the intersection points of the line perpendicular to the vertical axis with the longest distance between the line and the outline of the object), the vertical axis (the distance between the two farthest points on the outline of the object), and the aspect ratio of the rubber phase were measured, calculated, and statistically analyzed. The average size and aspect ratio of the horizontal axis were obtained based on 200 sampling points.

[0200] (13) Average particle size and maximum particle size of the rubber phase of propylene impact copolymer in the raw material The cross section of the impact test piece after gold spray treatment , Korea We used a scanning electron microscope, EM-30AX, manufactured by COXEM, Japan. Tesu The particle sizes of the rubber phase were measured and statistically analyzed to obtain the average and maximum particle sizes. For spherical particles, the diameter was measured, and for roughly spherical particles, the longitudinal axis of the particle (the distance between the two furthest points on the outline of the object) was measured. Based on 50 sample points, the maximum value of the above sizes was obtained as the maximum particle size, and the average value of the above sizes was calculated as the average particle size.

[0201] (14) The content of the copolymerized portion containing an ethylene unit, the content of the ethylene unit, and the content of the ethylene unit sequence [EEE] in the propylene impact copolymer. 13 CNMR was used to measure the

[0202] 13 C NMR was measured using a 400 MHz nuclear magnetic resonance spectrometer (NMR) manufactured by Bruker, Switzerland, with an AVANCE III instrument model. The solvent was deuterated o-dichlorobenzene, with a ratio of 250 mg sample to 2.5 mL solvent. 2 mg of BHT antioxidant was added to the sample to prevent oxidative degradation of the sample during dissolution and data collection. The test sample was dissolved at 140°C. 13C-NMR was taken and tested at a temperature of 125°C, a probe specification of 10 mm, a pulse of 90°, a sampling time AQ of 5 seconds, a delay time D1 of 1 second, and a scan number of 6000.

[0203] (15) Surface energy of film Measurement was performed in accordance with the method specified in GB / T14216-2008.

[0204] (16) Comonomer content of copolypropylene in grafted propylene polymer Comonomer content was measured by quantitative Fourier transform infrared (FTIR) spectroscopy. The correlation of the measured comonomer content was calibrated by quantitative nuclear magnetic resonance (NMR) spectroscopy. 13 Calibration methods based on the results obtained from C-NMR spectra were performed according to conventional methods in the art.

[0205] (17) Xylene solubles of copolypropylene in grafted propylene polymers, comonomer content in the solubles, and intrinsic viscosity ratio of the solubles to the copolypropylene For the test, a CRYST-EX device manufactured by Polymer Char was used. Trichlorobenzene solvent was used, and the dissolution temperature was raised to 150°C and kept constant for 90 minutes, after which a test sample was taken, and the temperature was lowered to 35°C and kept constant for 70 minutes, after which a test sample was taken.

[0206] (18) Weight average molecular weight of copolypropylene in grafted propylene polymer Measurements were performed by high-temperature GPC using a Polymer Laboratory PL-GPC 220 gel permeation chromatograph. The test sample was dissolved in 1,2,4-trichlorobenzene at a concentration of 1.0 mg / ml. The test temperature was 150°C, and the solution flow rate was 1.0 ml / min. A standard curve was established using the molecular weight of polystyrene as an internal standard, and the molecular weight and molecular weight distribution of the sample were calculated according to the elution time.

[0207] (19) Melting temperature (Tm) The melting and crystallization processes of the materials were analyzed using a differential scanning calorimeter. The specific procedure is as follows: Under nitrogen protection, 5-10 mg of samples were measured using a three-stage heating and cooling method from 20 to 200°C. The change in heat flow, which reflects the melting and crystallization processes of the material, was measured, and the melting temperature (Tm) was calculated.

[0208] (20) Grafting efficiency (GE), parameter M1 2–4 g of the grafted product was placed in a Soxhlet extractor and extracted with ethyl acetate (or acetone if an alkenyl-containing silane monomer was used as the grafting monomer) for 24 hours to remove unreacted monomers and their homopolymers, yielding a pure grafted product. This was then dried and weighed, and the parameter M1 and grafting efficiency (GE) were calculated.

[0209] The parameter M1 represents the total content of structural units derived from graft monomers in the grafted propylene polymer. The formulas for calculating M1 and GE were as follows:

number

number

[0210] In the above formula, w0 was the mass of the PP matrix; w1 was the mass of the grafted product before extraction; w2 was the mass of the grafted product after extraction; and w3 was the total mass of the added grafting monomers.

[0211] Maleic anhydride mass content %G MAHwas tested and calculated according to the method described in the literature (Zhang Guangping, Solid Phase Graft of Maleic Anhydride onto Polypropylene in Helical Ribbon Reactor, China Plastics, February 2002, Vol. 16, No. 2, 69-71). The parameter M2 represents the content of graft structural units derived from maleic anhydride monomer in the grafted propylene polymer. The calculation formula for M2 was as follows:

number

[0212] In the above formula, w1 is the mass of the grafted product before extraction, w2 is the mass of the grafted product after extraction, and %G MAH is the mass content of maleic anhydride.

[0213] (21) Volume resistivity Measurement was carried out in accordance with the method specified in GB / T1410-2006.

[0214] Example A1 (1) Preparation of Propylene Polymer Composition A for Preparation of Layer a Component a was a homopolypropylene with the trade name PPH-FA03 (available from Qingdao Refining & Chemical Co., Ltd., having a melt flow rate of 3.1 g / 10 min, an isotacticity of 98%, and a molecular weight distribution Mw / Mn of 4.7); component b was a propylene impact copolymer with the trade name EP200K (available from SINOPEC SABIC Petrochemical Co., Ltd., having an ethylene content of 8 wt%, an ethylene-propylene copolymer content of 13 wt%, and a melt flow rate of 3.2 g / 10 min); and component c was a polyolefin elastomer with the trade name 6102 (available from Exxon Corporation, obtained by copolymerization of propylene and ethylene, having an ethylene structural unit content of 16 wt%). The various components prepared above were weighed and mixed in the following proportions: 75 parts by weight of component a (Wa), 10 parts by weight of component b (Wb), and 15 parts by weight of component c (Wc). A lubricant (a PEG lubricant manufactured by Clariant, Switzerland, with a molecular weight of 10,000, added in an amount of 0.1 parts by weight based on 100 parts by weight of the total mass of the above components a, b, and c) was then added, and the mixture was then mixed uniformly in a high-speed mixer. The mixed material was then added to the feeder of a twin-screw extruder manufactured by W&P. The material entered the twin screws, and the screw temperature was maintained in the range of 160-230°C during processing. The material was melt-mixed uniformly by the screws, extruded, pelletized, and dried. Pellets of propylene polymer composition A were obtained, and after measurement, they had a melt flow rate of MFR A =3.6g / 10min.

[0215] (2) Preparation of Propylene Polymer Composition B for Preparation of Layer b Component x was a random propylene copolymer with the trade name F5006 (available from Yanshan Petrochemical Co., Ltd., an ethylene-propylene-butene terpolymer with a melt flow rate of 5.2 g / 10 min); component y was a polyolefin elastomer with the trade name 6102 (available from Exxon Corporation). The various components prepared above were weighed and mixed according to the ratio of 75 parts by weight of component x (Wx) and 25 parts by weight of component y (Wy). Wc:Wy was 3:5. The other procedures were the same as those in step (1), and finally pellets of propylene polymer composition B were obtained; after measurement, they had a melt flow rate of MFR B =3.2g / 10min.

[0216] (3) Preparation of composite films The pellets of propylene polymer composition A and propylene polymer composition B obtained in steps (1) and (2) above were dried. Then, propylene polymer composition A was added to the core layer extruder of a multi-layer extrusion casting machine, and propylene polymer composition B was added to the top layer extruder of the multi-layer extrusion casting machine. An inorganic antiblocking agent (silica, Mizusawa, Japan, trade name JC-50, hereinafter the same) was also added to the top layer extruder, and the weight ratio of the antiblocking agent to the propylene polymer composition pellets was 0.02:1. During the casting process, the temperature of the casting chill roll was set to 30°C. After winding, a composite film consisting of a top layer (layer b) and a core layer (layer a) was prepared. The film thickness was 50 μm, and the thickness ratio of layer b to layer a was 1:2.

[0217] An atomic force micrograph of the cross section of the composite film is shown in Figure 3. The black areas represent the rubber phase, which is dispersed, band-like, and parallel to each other. The rubber phase had an average horizontal size of 56 nm and an average aspect ratio of 10.3.

[0218] Example A2 (1) Preparation of Propylene Polymer Composition A for Preparation of Layer a Component a was a homopolypropylene with the trade name PPH-FA03 (available from Qingdao Refining & Chemical Co., Ltd., having a melt flow rate of 3.1 g / 10 min, an isotacticity of 98%, and a molecular weight distribution Mw / Mn of 4.7); component b was a propylene impact copolymer with the trade name M180R (available from Shanghai Petrochemical Co., Ltd., having an ethylene content of 11 wt %, an ethylene-propylene copolymer content of 15 wt %, and a melt flow rate of 2.0 g / 10 min); and component c was a polyolefin elastomer with the trade name DF640 (obtained by copolymerization of ethylene and butene, having a butene structural unit content of 32 wt %, available from Mitsui). The various components prepared above were weighed and mixed in the following proportions: 65 parts by weight of component a (Wa), 30 parts by weight of component b (Wb), and 5 parts by weight of component c (Wc). A lubricant (a PEG lubricant manufactured by Clariant, Switzerland, with a molecular weight of 10,000, added in an amount of 0.1 parts by weight based on 100 parts by weight of the total mass of the above components a, b, and c) was then added, and the mixture was then mixed uniformly in a high-speed mixer. The mixed material was then added to the feeder of a twin-screw extruder manufactured by W&P. The material entered the twin screws, and the screw temperature was maintained in the range of 160-230°C during processing. The material was melt-mixed uniformly by the screws, extruded, pelletized, and dried. Pellets of propylene polymer composition A were obtained, and after measurement, they had a melt flow rate of MFR A =3.2g / 10min.

[0219] (2) Preparation of Propylene Polymer Composition B for Preparation of Layer b Component x was a random propylene copolymer with the trade name F500EPS (ethylene-propylene-butene terpolymer available from Shanghai Petrochemical Co., Ltd., with a melt flow rate of 5.3 g / 10 min); component y was a polyolefin elastomer with the trade name DF640 (available from Mitsui Co., Ltd.). The various components prepared above were weighed and mixed according to the ratio of 90 parts by weight of component x (Wx) and 10 parts by weight of component y (Wy). Wc:Wy was 1:2. The other procedures were the same as those in step (1), and finally pellets of propylene polymer composition B were obtained; after measurement, they had a melt flow rate of MFR B =5.2g / 10min.

[0220] (3) Preparation of composite films The pellets of propylene polymer composition A and propylene polymer composition B obtained in steps (1) and (2) above were dried. Then, propylene polymer composition A was added to the core layer extruder of a multi-layer extrusion caster, and propylene polymer composition B was added to the top layer extruder and bottom layer extruder of the multi-layer extrusion caster. An inorganic anti-blocking agent (silica, the same as above) was also added to the top layer extruder and bottom layer extruder. The weight ratio of the anti-blocking agent to the propylene polymer composition pellets was 0.02:1. During the film casting process, the temperature of the casting chill roll was set to 30°C. After winding, a composite film consisting of top and bottom layers (layer b; layer c having the same composition as layer b) and a core layer (layer a) was prepared. The film thickness was 50 μm, and the ratio of the total thickness of the top and bottom layers to the thickness of the core layer was 1:1.

[0221] Example A3 (1) Preparation of propylene polymer composition A for the preparation of layer a: Component a is a homopolypropylene with the trade name FC801 (available from Shanghai Petrochemical Co., Ltd., having a melt flow rate of 7.8 g / 10 min, an isotacticity of 98%, and a molecular weight distribution Mw / Mn of 4.8); component b is a homopolypropylene with the trade name PPB-M02D (available from Maoming Petrochemical Co., Ltd., having an ethylene content of 8 wt.% and an ethylene-propylene copolymer content of 10 wt.%). , room Component a was a propylene impact copolymer having an ethylene unit content of 36.3% by weight in xylene solubles at room temperature, an ethylene unit sequence [EEE] content of 18.5% by weight, and a melt flow rate of 1.5 g / 10 min; and component c was a polyolefin elastomer with the trade name EXACT 3139 (obtained by copolymerization of ethylene and octene, having an octene structural unit content of 14% by weight, available from Exxon). The various components prepared above were weighed and mixed in proportions such that component a (Wa) was 55 parts by weight, component b (Wb) was 25 parts by weight, and component c (Wc) was 20 parts by weight. Next, a lubricant (a PEG lubricant manufactured by Clariant, Switzerland, with a molecular weight of 10,000, added in an amount of 0.1 parts by weight based on 100 parts by weight of the total mass of the above components a, b, and c) was added, and the mixture was then added to a high-speed mixer to mix uniformly. The mixed material was then added to the feeder of a twin-screw extruder manufactured by W&P, and the material entered the twin screws. The screw temperature was maintained in the range of 160 to 230°C during processing, and the material was melt-mixed uniformly by the screws, extruded, pelletized, and dried. Pellets of propylene polymer composition A were obtained, and after measurement, they had a melt flow rate of MFR A =6.6g / 10min.

[0222] (2) Preparation of Propylene Polymer Composition B for Preparation of Layer b Component x was a random propylene copolymer with the trade name F800EPS (ethylene-propylene-butene terpolymer with a melt flow rate of 8.2 g / 10 min, available from Shanghai Petrochemical Co., Ltd.); and component y was a polyolefin elastomer with the trade name EXACT3139 (available from Exxon Corporation). The various components prepared above were weighed and mixed according to the ratio of 80 parts by weight of component x (Wx) and 20 parts by weight of component y (Wy). Wc:Wy was 1:1. The other procedures were the same as those in step (1). Finally, pellets of propylene polymer composition B were obtained, and after measurement, they were found to have a melt flow rate of MFR B =7.9g / 10min.

[0223] (3) Preparation of composite films The preparation procedure was the same as step (3) of Example A1.

[0224] Example A4 (1) Preparation of Propylene Polymer Composition A for Preparation of Layer a The procedure was the same as that in step (1) of Example A1, except that the parts by weight Wa of component a was 80 parts by weight, the parts by weight Wb of component b was 18 parts by weight, and the parts by weight Wc of component c was 2 parts by weight. Finally, pellets of propylene polymer composition A were obtained, and after measurement, they had a melt flow rate of MFR A =2.8g / 10min.

[0225] (2) Preparation of Propylene Polymer Composition B for Preparation of Layer b The procedure was the same as that in step (2) of Example A1, except that the parts by weight Wx of component x was 92 parts by weight and the parts by weight Wy of component y was 8 parts by weight. Wc:Wy was 1:4. Finally, pellets of propylene polymer composition B were obtained, and after measurement, they had a melt flow rate of MFR B =7.7g / 10min.

[0226] (3) Preparation of composite films The procedure was the same as that in step (3) of Example A1. The thickness of the film was 50 μm, and the thickness ratio of layer b to layer a was 1:3.

[0227] Example A5 (1) Preparation of Propylene Polymer Composition A for Preparation of Layer a The procedure was the same as that in step (1) of Example A3, except that the parts by weight Wa of component a was 90 parts by weight, the parts by weight Wb of component b was 5 parts by weight, and the parts by weight Wc of component c was 5 parts by weight. Pellets of propylene polymer composition A were obtained, and after measurement, they had a melt flow rate MFR A =9.6g / 10min.

[0228] (2) Preparation of Propylene Polymer Composition B for Preparation of Layer b The procedure was the same as that in step (2) of Example A3, except that the parts by weight Wx of component x was 80 parts by weight and the parts by weight Wy of component y was 20 parts by weight. Wc:Wy was 1:4. Finally, pellets of propylene polymer composition B were obtained, and after measurement, they had a melt flow rate of MFR B =7.9g / 10min.

[0229] (3) Preparation of composite films The procedure was the same as that in step (3) of Example A2. The film thickness was 50 μm, and the ratio of the total thickness of the upper and lower layers to the thickness of the core layer was 2:1.

[0230] Example A6 (1) Preparation of Propylene Polymer Composition A for Preparation of Layer a The procedure was the same as that in step (1) of Example A3, except that the parts by weight Wa of component a was 50 parts by weight, the parts by weight Wb of component b was 40 parts by weight, and the parts by weight Wc of component c was 10 parts by weight. Pellets of propylene polymer composition A were obtained, and after measurement, they had a melt flow rate MFR A =4.6g / 10min.

[0231] (2) Preparation of Propylene Polymer Composition B for Preparation of Layer b The procedure was the same as that in step (2) of Example A3, except that the parts by weight Wx of component x was 60 parts by weight and the parts by weight Wy of component y was 40 parts by weight. Wc:Wy was 1:4. Finally, pellets of propylene polymer composition B were obtained, and after measurement, they had a melt flow rate of MFR B =9.8g / 10min.

[0232] (3) Preparation of composite films: The procedure was the same as that in step (3) of Example A3. The thickness of the film was 50 μm, and the ratio of the thickness of the top layer to the thickness of the core layer was 1:4.

[0233] Example A7 (1) Preparation of Propylene Polymer Composition A for Preparation of Layer a The procedure was the same as that in step (1) of Example A1, except that the parts by weight Wa of component a was 50 parts by weight, the parts by weight Wb of component b was 20 parts by weight, and the parts by weight Wc of component c was 30 parts by weight. Pellets of propylene polymer composition A were obtained, and after measurement, they had a melt flow rate MFR A =2.2g / 10min.

[0234] (2) Preparation of Propylene Polymer Composition B for Preparation of Layer b The procedure was the same as that in step (2) of Example A1, except that the parts by weight Wx of component x was 85 parts by weight and the parts by weight Wy of component y was 15 parts by weight. Wc:Wy was 2:1. Finally, pellets of propylene polymer composition B were obtained, and after measurement, they had a melt flow rate of MFR B =4.5g / 10min.

[0235] (3) Preparation of composite films The procedure was the same as that in step (3) of Example A1. The thickness of the film was 50 μm, and the thickness ratio of layer b to layer a was 1:3.

[0236] Example A8 A composite film was prepared as described in Example A1, except that in the preparation of propylene polymer composition A, the mass parts Wa of component a was 40 parts by weight, the mass parts Wb of component b was 40 parts by weight, and the mass parts Wc of component c was 20 parts by weight. Wc:Wy was 4:5. Pellets of propylene polymer composition A were obtained, and after measurement, they had a melt flow rate of MFR A =2.8g / 10min.

[0237] Example A9 A composite film was prepared as described in Example A1, except that in the preparation of propylene polymer composition A, the mass parts Wa of component a was 50 parts by weight, the mass parts Wb of component b was 45 parts by weight, and the mass parts Wc of component c was 5 parts by weight. Wc:Wy was 1:5. Pellets of propylene polymer composition A were obtained, and after measurement, they had a melt flow rate of MFR A =3.1g / 10min.

[0238] Example A10 A composite film was prepared as described in Example A1, except that in the preparation of propylene polymer composition A, the mass parts Wa of component a was 50 parts by weight, the mass parts Wb of component b was 10 parts by weight, and the mass parts Wc of component c was 40 parts by weight. Wc:Wy was 8:5. Pellets of propylene polymer composition A were obtained, and after measurement, they had a melt flow rate of MFR A =2.7g / 10min.

[0239] Example A11 A composite film was prepared as described in Example A1, except that in the preparation of propylene polymer composition B, the parts by weight Wx of component x was 50 parts by weight and the parts by weight Wy of component y was 50 parts by weight. Wc:Wy was 3:10. Pellets of propylene polymer composition B were obtained and, after measurement, they had a melt flow rate of MFR B =4.7g / 10min.

[0240] Example A12 A composite film was prepared as described in Example A1, except that propylene polymer composition B contained only component x.

[0241] Example A13 A composite film was prepared as described in Example A1, except that in the preparation of propylene polymer composition B, the parts by weight Wx of component x was 92.5 parts by weight and the parts by weight Wy of component y was 7.5 parts by weight. Wc:Wy was 2:1. Finally, pellets of propylene polymer composition B were obtained, and after measurement, they had a melt flow rate of MFR B =5.5g / 10min.

[0242] Example A14 A composite film was prepared as described in Example A1, except that in the preparation of propylene polymer composition B, the parts by weight Wx of component x was 85 parts by weight and the parts by weight Wy of component y was 15 parts by weight. Wc:Wy was 1:1. Finally, pellets of propylene polymer composition B were obtained, and after measurement, they had a melt flow rate of MFR B =5.1g / 10min.

[0243] Example A15 A composite film was prepared as described in Example A1, except that in the preparation of propylene polymer composition B, the parts by weight Wx of component x was 70 parts by weight and the parts by weight Wy of component y was 30 parts by weight. Wc:Wy was 1:2. Finally, pellets of propylene polymer composition B were obtained, and after measurement, they had a melt flow rate of MFR B =4.4g / 10min.

[0244] Example A16 A composite film was prepared as described in Example A1, except that in the preparation of propylene polymer composition B, the mass parts Wx of component x was 40 parts by weight and the mass parts Wy of component y was 60 parts by weight. Wc:Wy was 1:4. Finally, pellets of propylene polymer composition B were obtained, and after measurement, they had a melt flow rate of MFR B =2.9g / 10min.

[0245] Example A17 A composite film was prepared as described in Example A1, except that in the preparation of propylene polymer composition B, the parts by weight Wx of component x was 97 parts by weight and the parts by weight Wy of component y was 3 parts by weight. Wc:Wy was 5:1. Finally, pellets of propylene polymer composition B were obtained, and after measurement, they had a melt flow rate of MFR B =6.0g / 10min.

[0246] [Comparative Example A1] A composite film was prepared according to the procedure in Example A1, except that only propylene polymer composition A was used for extrusion casting to form a monolayer film with a film thickness of 50 μm.

[0247] [Comparative example A2] A composite film was prepared according to the procedure in Example A2, except that only propylene polymer composition B was used for extrusion casting to form a monolayer film with a film thickness of 50 μm.

[0248] [Comparative example A3] A composite film was prepared according to the procedure in Example A1, except that propylene polymer composition A contained only component b. As shown in Figure 4, AFM observation revealed that the rubber phase had an average horizontal size of 380 nm and an average aspect ratio of 23.4.

[0249] [Comparative example A4] A composite film was prepared according to the procedure in Example A1, except that propylene polymer composition A contained only component a and component b, the parts by weight Wa of component a was 75 parts by weight, and the parts by weight Wb of component b was 25 parts by weight.

[0250] [Comparative Example A5] A composite film was prepared according to the procedure in Example A1, except that propylene polymer composition A contained only component a and component c, the parts by weight Wa of component a was 75 parts by weight, and the parts by weight Wc of component c was 25 parts by weight.

[0251] [Table 1]

[0252] From the results in Table 1, it can be concluded that the composite film of the present invention can simultaneously have good impact resistance and optical properties, and even good tensile strength and good heat seal strength. Compared with a monolayer film or a composite film not according to the present invention, the composite film of the present invention can achieve a better balance of the above various properties, and during extrusion molding, the film has better surface stability and thickness uniformity.

[0253] Example B1 (1) Preparation of Propylene Polymer Composition A for Preparation of Layer a Component a was a homopolypropylene with the trade name PPH-FA03 (available from Qingdao Refining & Chemical Co., Ltd., having a melt flow rate of 3.1 g / 10 min, an isotacticity of 98%, and a molecular weight distribution Mw / Mn of 4.7); component b was a polyolefin elastomer with the trade name 6102 (available from Exxon Corporation). The various components prepared above were weighed and mixed in proportions such that component a (Wa) was 80 parts by weight and component b (Wb) was 20 parts by weight. Next, a lubricant (a PEG lubricant manufactured by Clariant, Switzerland, with a molecular weight of 10,000, added in an amount of 0.1 parts by weight based on 100 parts by weight of the total mass of the above-mentioned components a and b) was added, and the mixture was then added to a high-speed mixer to mix uniformly. The mixed material was then added to the feeder of a twin-screw extruder manufactured by W&P, and the material entered the twin screws. The screw temperature was maintained in the range of 160 to 230°C during processing, and the material was melt-mixed uniformly by the screws, extruded, pelletized, and dried. Pellets of propylene polymer composition A were obtained, and after measurement, they had a melt flow rate of MFR A =3.5g / 10min.

[0254] (2) Preparation of Propylene Polymer Composition B for Preparation of Layer b Component x was a random propylene copolymer with the trade name F5006 (available from Yanshan Petrochemical Co., Ltd., an ethylene-propylene-butene terpolymer with a melt flow rate of 5.2 g / 10 min); component y was a polyolefin elastomer with the trade name 6102 (available from Exxon Corporation); and component z was a propylene impact copolymer with the trade name EP200K (available from SINOPEC SABIC Petrochemical Co., Ltd., an ethylene content of 8 wt%, an ethylene-propylene copolymer content of 13 wt%, and a melt flow rate of 3.2 g / 10 min). The various components prepared above were weighed and mixed in the following proportions: 85 parts by weight of component x (Wx), 5 parts by weight of component y (Wy), and 10 parts by weight of component z (Wz). The Wb:Wy ratio was 4:1. The other procedures are the same as those in step (1), and finally, pellets of propylene polymer composition B are obtained. After measurement, they have a melt flow rate of MFR B =4.7g / 10min.

[0255] (3) Preparation of composite films The pellets of propylene polymer composition A and propylene polymer composition B obtained in steps (1) and (2) above were dried. Propylene polymer composition A was then added to the core layer extruder of a multi-layer extrusion caster, and propylene polymer composition B was added to the top layer extruder of the multi-layer extrusion caster. An inorganic anti-blocking agent (silica, as described above) was also added to the top layer extruder, and the weight ratio of the anti-blocking agent to the propylene polymer composition pellets was 0.02:1. During the casting process, the temperature of the casting chill roll was set to 30°C. After winding, a composite film consisting of a top layer (layer b) and a core layer (layer a) was prepared. The film thickness was 50 μm, and the thickness ratio of layer b to layer a was 1:2.

[0256] Example B2 (1) Preparation of Propylene Polymer Composition A for Preparation of Layer a Component a was a propylene impact copolymer with the trade name M180R (available from Shanghai Petrochemical Co., Ltd., having an ethylene content of 11 wt %, an ethylene-propylene copolymer content of 15 wt %, and a melt flow rate of 2.0 g / 10 min); component b was a polyolefin elastomer with the trade name DF640 (available from Mitsui Co., Ltd.). The various components prepared above were weighed and mixed in proportions such that component a (Wa) was 95 parts by weight and component b (Wb) was 5 parts by weight. Next, a lubricant (a PEG lubricant manufactured by Clariant, Switzerland, with a molecular weight of 10,000, added in an amount of 0.1 parts by weight based on 100 parts by weight of the total mass of the above-mentioned components a and b) was added, and the mixture was then added to a high-speed mixer to mix uniformly. The mixed material was then added to the feeder of a twin-screw extruder manufactured by W&P, and the material entered the twin screws. The screw temperature was maintained in the range of 160 to 230°C during processing, and the material was melt-mixed uniformly by the screws, extruded, pelletized, and dried. Pellets of propylene polymer composition A were obtained, and after measurement, they had a melt flow rate of MFR A =3.1g / 10min.

[0257] (2) Preparation of Propylene Polymer Composition B for Preparation of Layer b Component x was a random propylene copolymer with the trade name F500EPS (available from Shanghai Petrochemical Co., Ltd., an ethylene-propylene-butene terpolymer with a melt flow rate of 5.3 g / 10 min); component y was a polyolefin elastomer with the trade name DF640 (available from Mitsui); and component z was a propylene impact copolymer with the trade name M180R (available from Shanghai Petrochemical Co., Ltd., an ethylene content of 11 wt %, an ethylene-propylene copolymer content of 15 wt %, and a melt flow rate of 2.0 g / 10 min). The various components prepared above were weighed and mixed in a ratio of 60 parts by weight of component x (Wx), 20 parts by weight of component y (Wy), and 20 parts by weight of component z (Wz). The Wb:Wy ratio was 1:4. The other procedures are the same as those in step (1), and finally, pellets of propylene polymer composition B are obtained; after measurement, they have a melt flow rate of MFR B =4.4g / 10min.

[0258] (3) Preparation of composite films The pellets of propylene polymer composition A and propylene polymer composition B obtained in steps (1) and (2) above were dried. Then, propylene polymer composition A was added to the core layer extruder of a multi-layer extrusion caster, and propylene polymer composition B was added to the top layer extruder and bottom layer extruder of the multi-layer extrusion caster. An inorganic anti-blocking agent (silica, the same as above) was also added to the top layer extruder and bottom layer extruder. The weight ratio of the anti-blocking agent to the propylene polymer composition pellets was 0.02:1. During the film casting process, the temperature of the casting chill roll was set to 30°C. After winding, a composite film consisting of top and bottom layers (layer b; layer c having the same composition as layer b) and a core layer (layer a) was prepared. The film thickness was 50 μm, and the ratio of the total thickness of the top and bottom layers to the thickness of the core layer was 1:1.

[0259] Example B3 (1) Preparation of Propylene Polymer Composition A for Preparation of Layer a Component a was a homopolypropylene with the trade name FC801 (available from Shanghai Petrochemical Co., Ltd., having a melt flow rate of 7.8 g / 10 min, an isotacticity of 98%, and a molecular weight distribution Mw / Mn of 4.8); component b was a polyolefin elastomer with the trade name EXACT3139 (available from Exxon Corporation). The various components prepared above were weighed and mixed in proportions such that component a (Wa) was 85 parts by weight and component b (Wb) was 15 parts by weight. Next, a lubricant (a PEG lubricant manufactured by Clariant, Switzerland, with a molecular weight of 10,000, added in an amount of 0.1 parts by weight based on 100 parts by weight of the total mass of the above-mentioned components a and b) was added, and the mixture was then added to a high-speed mixer to mix uniformly. The mixed material was then added to the feeder of a twin-screw extruder manufactured by W&P, and the material entered the twin screws. The screw temperature was maintained in the range of 160 to 230°C during processing, and the material was melt-mixed uniformly by the screws, extruded, pelletized, and dried. Pellets of propylene polymer composition A were obtained, and after measurement, they had a melt flow rate of MFR A =7.9g / 10min.

[0260] (2) Preparation of Propylene Polymer Composition B for Preparation of Layer b Component x was a random propylene copolymer with the trade name F800EPS (available from Shanghai Petrochemical Co., Ltd.); component y was a polyolefin elastomer with the trade name EXACT3139 (available from Exxon); and component z was a polypropylene impact copolymer with the trade name PPB-M02D (available from Maoming Petrochemical Co., Ltd.). The various components prepared above were weighed and mixed according to the following proportions: Wx of component x was 85 parts by weight, Wy of component y was 10 parts by weight, and Wz of component z was 5 parts by weight. The Wb:Wy ratio was 3:2. The other procedures were the same as those in step (1), and finally pellets of propylene polymer composition B were obtained; after measurement, they had a melt flow rate of MFR B =7.4g / 10min.

[0261] (3) Preparation of composite films The preparation procedure was the same as step (3) in Example B1.

[0262] Example B4 (1) Preparation of Propylene Polymer Composition A for Preparation of Layer a The procedure was the same as that in step (1) of Example B1, except that the mass parts Wa of component a was 70 mass parts and the mass parts Wb of component b was 30 mass parts. Pellets of propylene polymer composition A were obtained and, after measurement, they had a melt flow rate MFR A =3.2g / 10min.

[0263] (2) Preparation of Propylene Polymer Composition B for Preparation of Layer b The procedure was the same as that in step (2) of Example B1, except that the parts by weight Wx of component x was 90 parts by weight, the parts by weight Wy of component y was 5 parts by weight, and the parts by weight Wz of component z was 5 parts by weight. The ratio of Wb:Wy was 6:1. The other procedures were the same as those in step (1). Finally, pellets of propylene polymer composition B were obtained, and after measurement, they had a melt flow rate of MFR B=8.2g / 10min.

[0264] (3) Preparation of composite films The procedure was the same as that in step (3) of Example B1. The thickness of the film was 50 μm, and the thickness ratio of layer b to layer a was 1:3.

[0265] Example B5 (1) Preparation of Propylene Polymer Composition A for Preparation of Layer a The procedure was the same as that in step (1) of Example B3, except that the mass parts Wa of component a was 75 mass parts and the mass parts Wb of component b was 25 mass parts. Pellets of propylene polymer composition A were obtained and, after measurement, they had a melt flow rate of MFR A =9.3g / 10min.

[0266] (2) Preparation of Propylene Polymer Composition B for Preparation of Layer b The procedure was the same as that in step (2) of Example B3, except that the parts by weight Wx of component x was 85 parts by weight, the parts by weight Wy of component y was 13 parts by weight, and the parts by weight Wz of component z was 2 parts by weight. Wb:Wy was 25:13. Finally, pellets of propylene polymer composition B were obtained, and after measurement, they had a melt flow rate of MFR B =9.2g / 10min.

[0267] (3) Preparation of composite films The procedure was the same as that in step (3) of Example B2. The film thickness was 50 μm, and the ratio of the total thickness of the upper and lower layers to the thickness of the core layer was 2:1.

[0268] Example B6 (1) Preparation of Propylene Polymer Composition A for Preparation of Layer a The procedure was the same as that in step (1) of Example B3, except that the mass parts Wa of component a was 100 parts by weight. Pellets of propylene polymer composition A were obtained and, after measurement, they had a melt flow rate of MFRA =7.8g / 10min.

[0269] (2) Preparation of Propylene Polymer Composition B for Preparation of Layer b The procedure was the same as that in step (2) of Example B3, except that the parts by weight Wx of component x was 50 parts by weight, the parts by weight Wy of component y was 30 parts by weight, and the parts by weight Wz of component z was 20 parts by weight. Finally, pellets of propylene polymer composition B were obtained, and after measurement, they had a melt flow rate MFR B =6.8g / 10min.

[0270] (3) Preparation of composite films The procedure was the same as that in step (3) of Example B3. The thickness of the film was 50 μm, and the ratio of the thickness of the top layer to the thickness of the core layer was 1:4.

[0271] Example B7 (1) Preparation of Propylene Polymer Composition A for Preparation of Layer a The procedure was the same as that in step (1) of Example B1. The mass parts Wa of component a was 100 parts by weight. Pellets of propylene polymer composition A were obtained and, after measurement, they had a melt flow rate of MFR A =3.1g / 10min.

[0272] (2) Preparation of Propylene Polymer Composition B for Preparation of Layer b The procedure was the same as that in step (2) of Example B1, except that the parts by weight Wx of component x was 50 parts by weight, the parts by weight Wy of component y was 20 parts by weight, and the parts by weight Wz of component z was 30 parts by weight. The other procedures were the same as those in step (1). Finally, pellets of propylene polymer composition B were obtained, and after measurement, they had a melt flow rate of MFR B =3.5g / 10min.

[0273] (3) Preparation of composite films The procedure was the same as that in step (3) of Example B1. The thickness of the film was 50 μm, and the thickness ratio of layer b to layer a was 1:3.

[0274] Example B8 A composite film was prepared as described in Example B1, except that in the preparation of propylene polymer composition A, the mass parts Wa of component a was 100 parts by weight. Finally, pellets of propylene polymer composition A were obtained, and after measurement, they had a melt flow rate of MFR A =3.1g / 10min.

[0275] Example B9 A composite film was prepared as described in Example B1, except that in the preparation of propylene polymer composition A, the mass parts Wa of component a was 50 parts by weight, and the mass parts Wb of component b was 50 parts by weight. Wb:Wy was 10:1. Finally, pellets of propylene polymer composition A were obtained, and after measurement, they had a melt flow rate of MFR A =3.5g / 10min.

[0276] Example B10 A composite film was prepared as described in Example B1, except that in the preparation of propylene polymer composition B, the parts by weight Wx of component x was 40 parts by weight, the parts by weight Wy of component y was 30 parts by weight, and the parts by weight Wz of component z was 30 parts by weight. Wb:Wy was 2:3. Pellets of propylene polymer composition B were obtained, and after measurement, they had a melt flow rate of MFR B =4.5g / 10min.

[0277] Example B11 A composite film was prepared as described in Example B1, except that in the preparation of propylene polymer composition B, the parts by weight Wx of component x was 50 parts by weight, the parts by weight Wy of component y was 40 parts by weight, and the parts by weight Wz of component z was 10 parts by weight. Wb:Wy was 1:2. Pellets of propylene polymer composition B were obtained, and after measurement, they had a melt flow rate of MFRB =5.0g / 10min.

[0278] Example B12 A composite film was prepared as described in Example B1, except that in the preparation of propylene polymer composition B, the parts by weight Wx of component x was 50 parts by weight, the parts by weight Wy of component y was 10 parts by weight, and the parts by weight Wz of component z was 40 parts by weight. Wb:Wy was 2:1. Pellets of propylene polymer composition B were obtained, and after measurement, they had a melt flow rate of MFR B =4.8g / 10min.

[0279] Example B13 A composite film was prepared as described in Example B1, except that in the preparation of propylene polymer composition A, the mass parts Wa of component a was 99 parts by weight and the mass parts Wb of component b was 1 part by weight. Wb:Wy was 1:5. Finally, the propylene polymer composition A After measuring, the melt flow rate of the pellets was determined to be MFR A =3.2g / 10min.

[0280] Example B14 A composite film was prepared as described in Example B1, except that in the preparation of propylene polymer composition A, the mass parts Wa of component a was 97.5 parts by weight and the mass parts Wb of component b was 2.5 parts by weight. Wb:Wy was 1:2. Finally, the propylene polymer composition A After measuring, the melt flow rate of the pellets was determined to be MFR A =3.1g / 10min.

[0281] Example B15 A composite film was prepared as described in Example B1, except that in the preparation of propylene polymer composition A, the mass parts Wa of component a was 95 parts by weight and the mass parts Wb of component b was 5 parts by weight. Wb:Wy was 1:1. Finally, the propylene polymer compositionA After measuring, the melt flow rate of the pellets was determined to be MFR A =3.2g / 10min.

[0282] Example B16 A composite film was prepared as described in Example B1, except that in the preparation of propylene polymer composition A, the mass parts Wa of component a was 90 parts by weight and the mass parts Wb of component b was 10 parts by weight. Wb:Wy was 2:1. Finally, the propylene polymer composition A After measuring, the melt flow rate of the pellets was determined to be MFR A =3.3g / 10min.

[0283] Example B17 A composite film was prepared as described in Example B1, except that in the preparation of propylene polymer composition A, the mass parts Wa of component a was 75 parts by weight and the mass parts Wb of component b was 25 parts by weight. Wb:Wy was 5:1. Finally, the propylene polymer composition A After measuring, the melt flow rate of the pellets was determined to be MFR A =3.1g / 10min.

[0284] [Comparative Example B1] A composite film was prepared as described in Example B1, except that only propylene polymer composition A was used for extrusion casting to form a monolayer film with a film thickness of 50 μm.

[0285] [Comparative example B2] A composite film was prepared as described in Example B2, except that only propylene polymer composition B was used for extrusion casting to form a monolayer film with a film thickness of 50 μm.

[0286] Comparative Example B3 A composite film was prepared as described in Example B1, except that propylene polymer composition B contained only component x.

[0287] [Comparative example B4] A composite film was prepared as described in Example B1, except that propylene polymer composition B contained only component x and component y, the parts by weight Wx of component x was 85 parts by weight, and the parts by weight Wy of component y was 15 parts by weight.

[0288] Example B18 A composite film was prepared as described in Example B2, except that propylene polymer composition B contained only component x and component z, the parts by weight Wx of component x was 70 parts by weight, and the parts by weight Wz of component z was 30 parts by weight.

[0289] [Table 2] From the results in Table 2, it can be concluded that the composite film of the present invention simultaneously had good impact resistance and optical properties, and even had good tensile properties and good heat seal strength. Compared with the monolayer film alone or the composite film not according to the present invention, the composite film of the present invention was able to achieve a good balance of various properties, and during extrusion molding, the film had better surface stability and thickness uniformity.

[0290] Example C1 The polyolefin elastomer used in steps (1) and (2) was a commercial product of Dow Chemical Company, a 160°C (160°F) ethylene-1-octene copolymer having an octene structural unit content of 38% by weight. -1 and 640r -1 Shear viscosity ratio η under shear rate 160 / η 640 Polyolefin elastomer having a viscosity of 2.18 and a viscosity of 640r at 230°C -1 Shear viscosity η under shear rate 640The procedure in Example A1 was essentially repeated, except that the polyolefin elastomer (elastomer having a melt flow rate of 185 Pa·s) was replaced with a polyolefin elastomer; and in step (3), the weight ratio of the antiblocking agent to the propylene polymer composition pellets was 0.2:100. A =3.8g / 10min, MFR B =4.2g / 10min.

[0291] An atomic force micrograph of the cross section of the composite film is shown in Figure 5. The black areas represent the rubber phase, which is dispersed, band-like, and parallel to each other. The rubber phase had an average horizontal size of 84 nm and an average aspect ratio of 8.8.

[0292] Example C2 The polyolefin elastomer used in steps (1) and (2) was a product of trade name DF844 (available from Mitsui Co., Ltd., an ethylene-1-butene copolymer having a butene structural unit content of 25% by weight, and a viscosity of 160 r at 230°C). -1 and 640r -1 Shear viscosity ratio η under shear rate 160 / η 640 A polyolefin elastomer having a viscosity of 1.75 and a viscosity of 640 r at 230°C. -1 Shear viscosity η under shear rate 640 The procedure in Example A2 was essentially repeated, except that the polyolefin elastomer (elastomer having a melt flow rate of 398 Pa·s) was replaced with a polyolefin elastomer; and in step (3), the weight ratio of the antiblocking agent to the propylene polymer composition pellets was 0.2:100. A =3.4g / 10min, MFR B =5.6g / 10min.

[0293] The composite films were observed under an atomic force microscope and the rubber phases were found to be dispersed, band-like, and aligned parallel to each other, with an average transverse size of 105 nm and an average aspect ratio of 8.5.

[0294] Example C3 (1) Preparation of Propylene Polymer Composition A for Preparation of Layer a Component a is a homopolypropylene with the trade name FC801 (available from Shanghai Petrochemical Co., Ltd., having a melt flow rate of 7.8 g / 10 min, an isotacticity of 98%, and a molecular weight distribution Mw / Mn of 4.8); component b is a propylene impact copolymer with the trade name PPB-M02D (available from Maoming Petrochemical Co., Ltd., having an ethylene content of 8 wt%, an ethylene-propylene copolymer content of 10 wt%, an ethylene unit content in xylene solubles at room temperature of 36.3 wt%, an ethylene unit sequence [EEE] content of 18.5 wt%, and a melt flow rate of 1.5 g / 10 min); component c is a propylene-ethylene copolymer with the trade name VM3980 (available from Exxon Corporation, having an ethylene structural unit content of 9 wt%, and a melt flow rate of 160 r at 230 °C). -1 and 640r -1 Shear viscosity ratio η under shear rate 160 / η 640 Polyolefin elastomer with a viscosity of 2.26 at 230°C. -1 Shear viscosity η under shear rate 640The polyolefin elastomer (elastomer with a viscosity of 205 Pa·s) was used. The various components prepared above were weighed and mixed according to the following ratios: component a (Wa) 55 parts by weight, component b (Wb) 25 parts by weight, and component c (Wc) 20 parts by weight. A lubricant (PEG lubricant manufactured by Clariant, Switzerland, with a molecular weight of 10,000, added in an amount of 0.1 parts by weight based on 100 parts by weight of the total mass of components a, b, and c) was then added, and the mixture was then added to a high-speed mixer for homogeneous mixing. The mixed material was then added to the feeder of a twin-screw extruder manufactured by W&P. The material entered the twin screws, and the screw temperature was maintained in the range of 160-230°C during processing. The material was homogeneously melt-mixed, extruded, pelletized, and dried. Pellets of propylene polymer composition A were obtained, and after measurement, they had a melt flow rate of MFR A =7.0g / 10min.

[0295] (2) Preparation of Propylene Polymer Composition B for Preparation of Layer b Component x is a random propylene copolymer with the trade name F800EDF (available from Shanghai Petrochemical Co., a propylene-ethylene copolymer with a melt flow rate of 7.8 g / 10 min); component y is a propylene-ethylene copolymer with the trade name VM3980 (available from Exxon Corporation, a propylene-ethylene copolymer with a content of 9 wt % ethylene structural units, a melt flow rate of 160 r at 230 °C). -1 and 640r -1 Shear viscosity ratio η under shear rate 160 / η 640 A polyolefin elastomer having a viscosity of 2.26 and a viscosity of 640 r at 230°C. -1 Shear viscosity η under shear rate 640The polyolefin elastomer was a polyolefin elastomer having a melt flow rate of 205 Pa·s. The various components prepared above were weighed and mixed in a ratio of 80 parts by weight of component x (Wx) and 20 parts by weight of component y (Wy). The other procedures were the same as those in step (1). Finally, pellets of propylene polymer composition B were obtained, and after measurement, they were found to have a melt flow rate of MFR B =8.3g / 10min.

[0296] (3) Preparation of composite films The pellets of propylene polymer composition A and propylene polymer composition B obtained in steps (1) and (2) above were dried. Then, propylene polymer composition A was added to the core layer extruder of a multi-layer extrusion caster, and propylene polymer composition B was added to the top layer extruder and bottom layer extruder of the multi-layer extrusion caster. An inorganic antiblocking agent (silica, the same as above) was added to the top layer extruder and bottom layer extruder, with the weight ratio of the antiblocking agent to the propylene polymer composition pellets being 0.2:100. During the film casting process, the temperature of the casting chill roll was set to 30°C. After winding, a composite film consisting of top and bottom layers (layer b; layer c having the same composition as layer b) and a core layer (layer a) was prepared. The film thickness was 50 μm, and the ratio of the combined thickness of the top and bottom layers to the thickness of the core layer was 1:4.

[0297] Observation of the composite films under an atomic force microscope revealed that the rubber phases were dispersed, band-like, and aligned parallel to each other, with an average transverse size of 88 nm and an average aspect ratio of 9.6.

[0298] Example C4 (1) Preparation of Propylene Polymer Composition A for Preparation of Layer a The procedure was the same as that in step (1) of Example C1, except that the weight parts of component a (Wa) were 80 parts by weight, the weight parts of component b (Wb) were 18 parts by weight, and the weight parts of component c (Wc) were 2 parts by weight. Component c was 8411 (available from Dow, an ethylene-1-octene copolymer with an octene structural unit content of 36% by weight, 160°C at 230°C). -1 and 640r -1 Shear viscosity ratio η under shear rate 160 / η 640 Polyolefin elastomer having a viscosity of 1.80 at 230°C. -1 Shear viscosity η under shear rate 640 The pellets of propylene polymer composition A were obtained and after measurement, they were found to have a melt flow rate of MFR A =2.6g / 10min.

[0299] (2) Preparation of Propylene Polymer Composition B for Preparation of Layer b The procedure was the same as that in step (2) of Example C1, except that the parts by weight Wx of component x was 92 parts by weight and the parts by weight Wy of component y was 8 parts by weight. The other procedures were the same as those in step (1). Finally, pellets of propylene polymer composition B were obtained, and after measurement, they had a melt flow rate of MFR B =7.5g / 10min.

[0300] (3) Preparation of composite films The procedure was the same as that in step (3) of Example C1. The thickness of the film was 50 μm, and the thickness ratio of layer b to layer a was 1:6.

[0301] Observation of the composite film under an atomic force microscope revealed that the rubber phases were dispersed, band-like, and aligned parallel to each other, with an average transverse size of 196 nm and an average aspect ratio of 5.3.

[0302] Example C5 (1) Preparation of Propylene Polymer Composition A for Preparation of Layer a The procedure was the same as that in step (1) of Example C1, except that the parts by weight Wa of component a was 90 parts by weight, the parts by weight Wb of component b was 5 parts by weight, and the parts by weight Wc of component c was 5 parts by weight. Pellets of propylene polymer composition A were obtained, and after measurement, they had a melt flow rate MFR A =3.0 g / 10 min.

[0303] (2) Preparation of Propylene Polymer Composition B for Preparation of Layer b The procedure was the same as that in step (2) of Example C1, except that the parts by weight Wx of component x was 80 parts by weight and the parts by weight Wy of component y was 20 parts by weight. Finally, pellets of propylene polymer composition B were obtained, and after measurement, they had a melt flow rate of MFR B =3.5g / 10min.

[0304] (3) Preparation of composite films The procedure was the same as that in step (3) of Example C2. The film thickness was 50 μm, and the ratio of the total thickness of the upper and lower layers to the thickness of the core layer was 2:1.

[0305] Example C6 (1) Preparation of Propylene Polymer Composition A for Preparation of Layer a The procedure was the same as that in step (1) of Example C3, except that the parts by weight Wa of component a was 50 parts by weight, the parts by weight Wb of component b was 40 parts by weight, and the parts by weight Wc of component c was 10 parts by weight. Pellets of propylene polymer composition A were obtained, and after measurement, they had a melt flow rate of MFR A =4.8g / 10min.

[0306] (2) Preparation of Propylene Polymer Composition B for Preparation of Layer b The procedure was the same as that in step (2) of Example C3, except that the parts by weight Wx of component x was 60 parts by weight and the parts by weight Wy of component y was 40 parts by weight. Finally, pellets of propylene polymer composition B were obtained, and after measurement, they had a melt flow rate of MFR B =9.6g / 10min.

[0307] (3) Preparation of composite films The procedure was the same as that in step (3) of Example C3.

[0308] Observation of the composite films under an atomic force microscope revealed that the rubber phases were dispersed, band-like, and aligned parallel to each other, with an average transverse size of 23 nm and an average aspect ratio of 19.8.

[0309] Example C7 (1) Preparation of Propylene Polymer Composition A for Preparation of Layer a The procedure was the same as that in Example C1, except that the parts by weight Wa of component a was 50 parts by weight, the parts by weight Wb of component b was 20 parts by weight, and the parts by weight Wc of component c was 30 parts by weight. Pellets of propylene polymer composition A were obtained and, after measurement, they had a melt flow rate MFR A =2.0 g / 10 min.

[0310] (2) Preparation of Propylene Polymer Composition B for Preparation of Layer b The procedure was the same as that in step (2) of Example C1, except that the parts by weight Wx of component x was 85 parts by weight and the parts by weight Wy of component y was 15 parts by weight. The other procedures were the same as those in step (1). Finally, pellets of propylene polymer composition B were obtained, and after measurement, they had a melt flow rate of MFR B =4.3g / 10min.

[0311] (3) Preparation of composite films The procedure was the same as that in Example C1. The film thickness was 50 μm, and the thickness ratio of layer b to layer a was 1:3.

[0312] Observation of the composite film under an atomic force microscope revealed that the rubber phases were dispersed, band-like, and aligned parallel to each other, with an average transverse size of 145 nm and an average aspect ratio of 12.1.

[0313] Example C8 A propylene polymer film was prepared as described in Example C1, except that in the preparation of propylene polymer composition A, the parts by weight Wa of component a was 40 parts by weight, the parts by weight Wb of component b was 40 parts by weight, and the parts by weight Wc of component c was 20 parts by weight. Pellets of propylene polymer composition A were obtained and, after measurement, they had a melt flow rate of MFR A =3.1g / 10min.

[0314] Observation of the composite film under an atomic force microscope revealed that the rubber phases were dispersed, band-like, and aligned parallel to each other, with an average transverse size of 88 nm and an average aspect ratio of 17.0.

[0315] Example C9 A propylene polymer film was prepared as described in Example 1, except that in the preparation of propylene polymer composition B, the parts by weight Wx of component x was 95 parts by weight and the parts by weight Wy of component y was 5 parts by weight. Finally, pellets of propylene polymer composition B were obtained, and after measurement, they had a melt flow rate MFR B =5.5g / 10min.

[0316] Example C10 A propylene polymer film was prepared as described in Example C1, except that in the preparation of propylene polymer composition B, the parts by weight Wx of component x was 70 parts by weight and the parts by weight Wy of component y was 30 parts by weight. Finally, pellets of propylene polymer composition B were obtained, and after measurement, they had a melt flow rate MFR B =4.7g / 10min.

[0317] Example C11 A propylene polymer film was prepared as described in Example C1, except that in the preparation of propylene polymer composition B, the parts by weight Wx of component x was 40 parts by weight and the parts by weight Wy of component y was 60 parts by weight. Finally, pellets of propylene polymer composition B were obtained, and after measurement, they had a melt flow rate MFR B =3.2g / 10min.

[0318] Example C12 Propylene polymer composition A was prepared as described in Example C3 and propylene polymer composition B was prepared as described in Example C2, resulting in (ηA 160 -ηB 160 ) and (ηA 640 -ηB 640 ) were both less than 0. Composite films were prepared as described in Example C3.

[0319] Comparative Example C1 In preparing the propylene polymer composition A, the polyolefin elastomer c was a propylene polymer under the trade name DF744 (available from Mitsui Co., Ltd., having a butene structural unit content of 28% by weight and a viscosity of 160 r at 230°C). -1 and 640r -1 Shear viscosity ratio η under shear rate 160 / η 640 A polyolefin elastomer having a viscosity of 1.63 at 230°C and a viscosity of 640°C at 230°C. -1 Shear viscosity η under shear rate 640A propylene polymer film was prepared as described in Example C1, except that the polyolefin elastomer of propylene polymer composition A was replaced with a polyolefin elastomer having a melt flow rate of 554 Pa·s. Finally, pellets of propylene polymer composition A were obtained, and after measurement, they were found to have a melt flow rate of MFR A =2.4g / 10min.

[0320] Comparative Example C2 In preparing the propylene polymer composition B, polyolefin elastomer y was replaced with a propylene-octene copolymer (available from Dow, trade name 8400, a propylene-octene copolymer having an octene structural unit content of 35%, having a viscosity of 160°C at 230°C). -1 and 640r -1 Shear viscosity ratio η under shear rate 160 / η 640 A polyolefin elastomer having a viscosity of 2.45 and a viscosity of 640 r at 230°C. -1 Shear viscosity η under shear rate 640 A propylene polymer film was prepared as described in Example C2, except that the polyolefin elastomer of propylene polymer composition B was replaced with a polyolefin elastomer having a melt flow rate of 84 Pa·s. Finally, pellets of propylene polymer composition B were obtained, and after measurement, they were found to have a melt flow rate of MFR B =8.4g / 10min.

[0321] Comparative Example C3 A composite film was prepared as described in Example C1, except that propylene polymer composition B contained only component x.

[0322] [Comparative example C4] A composite film was prepared as described in Example C1, except that propylene polymer composition A contained only component a and component b, the parts by weight Wa of component a was 75 parts by weight, and the parts by weight Wb of component b was 25 parts by weight.

[0323] [Comparative example C5] A composite film was prepared as described in Example C1, except that propylene polymer composition A contained only component a and component c, the parts by weight Wa of component a was 75 parts by weight, and the parts by weight Wc of component c was 25 parts by weight.

[0324] [Table 3]

[0325] [Table 4]

[0326] From the results in Tables 3 and 4, it can be concluded that the composite films according to the present invention simultaneously had good impact resistance and optical properties, and even had good film uniformity. In particular, when a polyolefin elastomer having a specific shear viscosity was used, the film surface was stable during extrusion casting, and both the film thickness uniformity and impact resistance uniformity were significantly improved.

[0327] Example D1 The procedure in Example B1 was essentially repeated with the following exceptions.

[0328] The polyolefin elastomer used in step (1) was a polyolefin elastomer manufactured by Dow Chemical Company under the trade name 8411 (an ethylene-1-octene copolymer having an octene structural unit content of 36% by weight, and having a viscosity of 160 r / min at 230°C). -1 and 640r -1 Shear viscosity ratio η under shear rate 160 / η 640 A polyolefin elastomer having a viscosity of 1.80 at 230°C and a viscosity of 640°C -1 The pellets of the obtained propylene polymer composition A were replaced with a polyolefin elastomer having a melt flow rate of MFR A =3.4g / 10min.

[0329] The polyolefin elastomer used in step (2) was a polyolefin elastomer manufactured by Dow Chemical Company under the trade name of 8200 (an ethylene-1-octene copolymer having an octene structural unit content of 38% by weight, and having a viscosity of 160°C at 230°C). -1 and 640r -1 Shear viscosity ratio η under shear rate 160 / η 640 Polyolefin elastomer having a viscosity of 2.18 and a viscosity of 640r at 230°C -1 Shear viscosity η under shear rate 640 The resulting pellets of propylene polymer composition B were replaced with a polyolefin elastomer having a melt flow rate of MFR B =4.9g / 10min.

[0330] In step (3), the weight ratio of the antiblocking agent to the propylene polymer composition pellets was 0.2:100.

[0331] The composite films were examined under an atomic force microscope and the rubber phases were found to be dispersed, band-like, and parallel to each other, with an average transverse size of 72 nm and an average aspect ratio of 5.5.

[0332] Example D2 The polyolefin elastomer used in steps (1) and (2) was a product of trade name DF844 (available from Mitsui Co., Ltd., an ethylene-1-butene copolymer having a butene structural unit content of 25% by weight, and a viscosity of 160 r at 230°C). -1 and 640r -1 Shear viscosity ratio η under shear rate 160 / η 640 A polyolefin elastomer having a viscosity of 1.75 and a viscosity of 640 r at 230°C. -1 Shear viscosity η under shear rate 640The procedure in Example B2 was essentially repeated, except that the polyolefin elastomer (elastomer having a viscosity of 398 Pa·s) was replaced with the antiblocking agent; and in step (3), the weight ratio of the antiblocking agent to the propylene polymer composition pellets was 0.2:100. A =3.3g / 10min, MFR B =4.5g / 10min.

[0333] Observation of the composite films under an atomic force microscope revealed that the rubber phases were dispersed, band-like, and aligned parallel to each other, with an average transverse size of 130 nm and an average aspect ratio of 6.4.

[0334] Example D3 (1) Preparation of Propylene Polymer Composition A for Preparation of Layer a Component a is a homopolypropylene with the trade name FC801 (available from Shanghai Petrochemical Co., Ltd., having a melt flow rate of 7.8 g / 10 min, an isotacticity of 98%, and a molecular weight distribution Mw / Mn of 4.8); component b is a propylene-ethylene copolymer with the trade name VM3980 (available from Exxon Corporation, having an ethylene structural unit content of 9 wt %, and a melt viscosity of 160 r at 230 °C). -1 and 640r -1 Shear viscosity ratio η under shear rate 160 / η 640 A polyolefin elastomer having a viscosity of 2.26 and a viscosity of 640 r at 230°C. -1The polyolefin elastomer (elastomer with a shear viscosity of 205 Pa·s at a shear rate of 100°C) was used. The various components prepared above were weighed and mixed according to the ratio of 85 parts by weight of component a (Wa) and 15 parts by weight of component b (Wb). A lubricant (PEG lubricant manufactured by Clariant, Switzerland, with a molecular weight of 10,000, added in an amount of 0.1 parts by weight based on 100 parts by weight of the total mass of components a and b) was then added, and the mixture was then added to a high-speed mixer for homogeneous mixing. The mixed material was then added to the feeder of a twin-screw extruder manufactured by W&P. The material entered the twin screws, and the screw temperature was maintained in the range of 160-230°C during processing. The material was homogeneously melt-mixed by the screws, extruded, pelletized, and dried. Pellets of propylene polymer composition A were obtained, and after measurement, they had a melt flow rate of MFR A =7.4g / 10min.

[0335] (2) Preparation of Propylene Polymer Composition B for Preparation of Layer b Component x is a random propylene copolymer with the trade name F800EDF (available from Shanghai Petrochemical Co., an ethylene-propylene copolymer with a melt flow rate of 7.8 g / 10 min); component y is a propylene-ethylene copolymer with the trade name VM3980 (available from Exxon Corporation, a propylene-ethylene copolymer with an ethylene structural unit content of 9 wt %, a melt flow rate of 160 r at 230 °C). -1 and 640r -1 Shear viscosity ratio η under shear rate 160 / η 640 A polyolefin elastomer having a viscosity of 2.26 and a viscosity of 640 r at 230°C. -1The component z was a propylene impact copolymer with the trade name PPB-M02D (available from Maoming Petrochemical Co., Ltd., having an ethylene content of 8 wt%, an ethylene-propylene copolymer content of 10 wt%, an ethylene unit content in xylene solubles at room temperature of 36.3 wt%, an ethylene unit sequence [EEE] content of 18.5 wt%, and a melt flow rate of 1.5 g / 10 min). The various components prepared above were weighed and mixed in proportions of 85 wt parts of component x (Wx), 10 wt parts of component y (Wy), and 5 wt parts of component z (Wz). The other procedures were the same as those in step (1). Finally, pellets of propylene polymer composition B were obtained, and after measurement, they had a melt flow rate of MFR B =7.9g / 10min.

[0336] (3) Preparation of composite films The preparation procedure was the same as that in step (3) of Example D1.

[0337] Observation of the composite film under an atomic force microscope revealed that the rubber phases were dispersed, band-like, and aligned parallel to each other, with an average transverse size of 72 nm and an average aspect ratio of 13.2.

[0338] Example D4 (1) Preparation of Propylene Polymer Composition A for Preparation of Layer a The procedure was the same as that in step (1) of Example D1, except that the parts by weight Wa of component a was 70 parts by weight and the parts by weight Wb of component b was 30 parts by weight. Pellets of propylene polymer composition A were obtained and, after measurement, they had a melt flow rate MFR A =3.5g / 10min.

[0339] (2) Preparation of Propylene Polymer Composition B for Preparation of Layer b The procedure was the same as that in step (2) of Example D1, except that the parts by weight Wx of component x was 90 parts by weight, the parts by weight Wy of component y was 5 parts by weight, and the parts by weight Wz of component z was 5 parts by weight. The other procedures were the same as those in step (1). Finally, pellets of propylene polymer composition B were obtained, and after measurement, they had a melt flow rate of MFR B =5.2g / 10min.

[0340] (3) Preparation of composite films The procedure was the same as that in step (3) of Example D1. The thickness of the film was 50 μm, and the thickness ratio of layer b to layer a was 1:3.

[0341] Example D5 (1) Preparation of Propylene Polymer Composition A for Preparation of Layer a The procedure was the same as that in step (1) of Example D3, except that the parts by weight Wa of component a was 75 parts by weight and the parts by weight Wb of component b was 25 parts by weight. Pellets of propylene polymer composition A were obtained and, after measurement, they had a melt flow rate of MFR A =9.0g / 10min.

[0342] (2) Preparation of Propylene Polymer Composition B for Preparation of Layer b The procedure was the same as that in step (2) of Example D3, except that the parts by weight Wx of component x was 85 parts by weight, the parts by weight Wy of component y was 13 parts by weight, and the parts by weight Wz of component z was 2 parts by weight. Finally, pellets of propylene polymer composition B were obtained, and after measurement, they had a melt flow rate MFR B =9.3g / 10min.

[0343] (3) Preparation of composite films This step was the same as that in Example D2. The thickness of the film was 50 μm, and the ratio of the total thickness of the upper and lower layers to the thickness of the core layer was 2:1.

[0344] Example D6 (1) Preparation of Propylene Polymer Composition A for Preparation of Layer a The procedure was the same as that in step (1) of Example D3.

[0345] (2) Preparation of Propylene Polymer Composition B for Preparation of Layer b The procedure was as follows: Component x (Wx) was 50 parts by weight, component y (Wy) was 30 parts by weight, and component y was 8411 (an ethylene-1-octene copolymer having an octene structural unit content of 36% by weight, available from Dow, 160°C at 230°C). -1 and 640r -1 Shear viscosity ratio η under shear rate 160 / η 640 A polyolefin elastomer having a viscosity of 1.80 at 230°C and a viscosity of 640°C -1 The procedure was the same as in step (2) of Example D3, except that the polyolefin elastomer was a polyolefin elastomer having a shear viscosity of 148 Pa·s at a shear rate of 100°C, and the mass parts Wz of component z was 20 parts by weight. Finally, pellets of propylene polymer composition B were obtained, and after measurement, they were found to have a melt flow rate of MFR B =9.0g / 10min.

[0346] (3) Preparation of composite films The procedure was the same as that in step (3) of Example D3. The thickness of the film was 50 μm, and the ratio of the thickness of the top layer to the thickness of the core layer was 1:4.

[0347] Observation of the composite films under an atomic force microscope revealed that the rubber phases were dispersed, band-like, and aligned parallel to each other, with an average transverse size of 25 nm and an average aspect ratio of 19.7.

[0348] Example D7 (1) Preparation of Propylene Polymer Composition A for Preparation of Layer a The procedure was the same as that in step (1) of Example D1.

[0349] (2) Preparation of Propylene Polymer Composition B for Preparation of Layer b The procedure was the same as that in step (2) of Example D1, except that the parts by weight Wx of component x was 50 parts by weight, the parts by weight Wy of component y was 20 parts by weight, and the parts by weight Wz of component z was 30 parts by weight. The other procedures were the same as those in step (1). Finally, pellets of propylene polymer composition B were obtained, and after measurement, they had a melt flow rate of MFR B =3.7g / 10min.

[0350] (3) Preparation of composite films The procedure was the same as that in step (3) of Example D1. The thickness of the film was 50 μm, and the thickness ratio of layer b to layer a was 1:3.

[0351] Observation of the composite film under an atomic force microscope revealed that the rubber phases were dispersed, band-like, and aligned parallel to each other, with an average transverse size of 67 nm and an average aspect ratio of 17.5.

[0352] Example D8 A composite film was prepared as described in Example D1, except that in the preparation of propylene polymer composition A, the mass parts Wa of component a was 50 parts by weight and the mass parts Wb of component b was 50 parts by weight. Finally, pellets of propylene polymer composition A were obtained, and after measurement, they had a melt flow rate of MFR A =3.6g / 10min.

[0353] Observation of the composite film under an atomic force microscope revealed that the rubber phases were dispersed, band-like, and aligned parallel to each other, with an average transverse size of 190 nm and an average aspect ratio of 5.1.

[0354] Example D9 A composite film was prepared as described in Example D1, except that in the preparation of propylene polymer composition B, the parts by weight Wx of component x was 40 parts by weight, the parts by weight Wy of component y was 30 parts by weight, and the parts by weight Wz of component z was 30 parts by weight. Pellets of propylene polymer composition B were obtained and, after measurement, they had a melt flow rate MFR B =4.4g / 10min.

[0355] Observation of the composite films under an atomic force microscope revealed that the rubber phases were dispersed, band-like, and aligned parallel to each other, with an average transverse size of 145 nm and an average aspect ratio of 7.8.

[0356] Example D10 A composite film was prepared as described in Example D1, except that in the preparation of propylene polymer composition B, the parts by weight Wx of component x was 50 parts by weight, the parts by weight Wy of component y was 40 parts by weight, and the parts by weight Wz of component z was 10 parts by weight. Pellets of propylene polymer composition B were obtained and, after measurement, they had a melt flow rate MFR B =5.1g / 10min.

[0357] Observation of the composite films under an atomic force microscope revealed that the rubber phases were dispersed, band-like, and aligned parallel to each other, with an average transverse size of 85 nm and an average aspect ratio of 18.3.

[0358] Example D11 Propylene polymer composition A was prepared as described in Example D3, and propylene polymer composition B was prepared as described in Example D2, resulting in (ηA 160 -ηB 160 ) and (ηA 640 -ηB 640 ) were both less than 0. Composite films were prepared as described in Example D3.

[0359] [Comparative Example D1] Polyolefin elastomer b was DF740 (available from Mitsui Co., Ltd., 160°C at 230°C) -1 and 640r -1 Shear viscosity ratio η under shear rate 160 / η 640 A polyolefin elastomer having a viscosity of 1.63 and a viscosity of 640r at 230°C. -1 A composite film was prepared as described in Example D1, except that the propylene polymer composition A was replaced with a polyolefin elastomer having a melt flow rate of MFR A = 2.6 g / 10 min. The film thickness was 50 μm.

[0360] [Comparative example D2] Polyolefin elastomer y was used, trade name DF740 (available from Mitsui Co., Ltd., 160°C at 230°C) -1 and 640r -1 Shear viscosity ratio η under shear rate 160 / η 640 A polyolefin elastomer having a viscosity of 1.63 and a viscosity of 640r at 230°C. -1 A composite film was prepared as described in Example D2, except that the polyolefin elastomer of propylene polymer composition B was replaced with a polyolefin elastomer having a shear viscosity of 554 Pa·s at a shear rate of 1000 rpm. Pellets of propylene polymer composition B were obtained and, after measurement, they were found to have a melt flow rate of MFR B = 4.2 g / 10 min. The film thickness was 50 μm.

[0361] [Comparative Example D3] A composite film was prepared as described in Example D1, except that propylene polymer composition B contained only component x.

[0362] [Comparative Example D4] A composite film was prepared as described in Example D1, except that propylene polymer composition B contained only component x and component y, the parts by weight Wx of component x was 85 parts by weight, and the parts by weight Wy of component y was 15 parts by weight.

[0363] Example D12 A composite film was prepared as described in Example D2, except that propylene polymer composition B contained only component x and component z, the parts by weight Wx of component x was 70 parts by weight, and the parts by weight Wz of component z was 30 parts by weight.

[0364] [Comparative Example D5] A composite film was prepared as described in Example D2, except that propylene polymer composition A contained only component a.

[0365] [Table 5]

[0366] [Table 6]

[0367] From the results in Tables 5 and 6, it can be concluded that the composite films according to the present invention simultaneously had good impact resistance and optical properties. Compared with composite films not according to the present invention, the composite films according to the present invention had better overall properties, and in particular, when a polyolefin elastomer having a specific shear viscosity was used, the film surface was stable during extrusion molding, and both the uniformity of the film thickness and the uniformity of the impact resistance were significantly improved.

[0368] Example E1 (1) Preparation of Propylene Polymer Composition A for Preparation of Layer a Component a is a propylene impact copolymer with the trade name J410F (available from Hyosung, Korea; the rubber phase has an average particle size of 600 nm, a maximum particle size of 800 nm, an ethylene unit content of 5.3 wt%, an ethylene-propylene copolymer content of 7.2 wt%, an ethylene unit content in the xylene soluble matter at room temperature of 26.0 wt%, an ethylene unit sequence [EEE] content of 6.9 wt%, and a melt flow rate of 4.6 g / 10 min; Figure 6a shows an SEM photograph of the cross section of a propylene impact copolymer specimen); component b is a homopolypropylene with the trade name PPH-FA03 (available from Qingdao Refining & Chemical Co., Ltd.; the melt flow rate is 3.0 g / 10 min and the molecular weight distribution Mw / Mn is 4.6); and component c is a homopolypropylene with the trade name DF840 (available from Mitsui; ethylene-1-butene The resulting mixture was a polyolefin elastomer (copolymer). The various components prepared above were weighed and mixed according to the following ratios: 65 parts by weight of component a (Wa), 30 parts by weight of component b (Wb), and 5 parts by weight of component c (Wc). A lubricant (PEG lubricant manufactured by Clariant, Switzerland, with a molecular weight of 10,000, added in an amount of 0.1 parts by weight based on 100 parts by weight of the total mass of the above components a, b, and c) was then added, and the mixture was then added to a high-speed mixer for homogeneous mixing. The mixed material was then added to the feeder of a twin-screw extruder manufactured by W&P. The material entered the twin screws, and the screw temperature was maintained in the range of 160-230°C during processing. The material was homogeneously melt-mixed, extruded, pelletized, and dried. Pellets of propylene polymer composition A were obtained, and after measurement, they had a melt flow rate of MFR A =4.1g / 10min.

[0369] (2) Preparation of Propylene Polymer Composition B for Preparation of Layer b Component x was a propylene random copolymer with the trade name F500EPS (available from Shanghai Petrochemical Co., Ltd., an ethylene-propylene-butene terpolymer with a melt flow rate of 5.3 g / 10 min); component y was a polyolefin elastomer with the trade name DF840 (available from Mitsui Co., Ltd., an ethylene-1-butene copolymer). The various components prepared above were weighed and mixed according to the ratio of 90 parts by weight of component x (Wx) and 10 parts by weight of component y (Wy). The other procedures were the same as those in step (1). Finally, pellets of propylene polymer composition B were obtained, and after measurement, they were found to have a melt flow rate of MFR B =5.6g / 10min.

[0370] (3) Preparation of composite films The pellets of propylene polymer composition A and propylene polymer composition B obtained in steps (1) and (2) above were dried. Then, propylene polymer composition A was added to the core layer extruder of a multi-layer extrusion caster, and propylene polymer composition B was added to the top layer extruder and bottom layer extruder of the multi-layer extrusion caster. An inorganic antiblocking agent (silica, as described above) was added to the top layer extruder and bottom layer extruder, with the weight ratio of the antiblocking agent to the propylene polymer composition pellets being 0.2:100. During the film casting process, the temperature of the casting chill roll was set to 30°C. After winding, a composite film consisting of the top layer, the bottom layer (layer b) and the core layer (layer a) was prepared. The film thickness was 50 μm, and the ratio of the total thickness of the top layer and the bottom layer to the thickness of the core layer was 1:1.

[0371] An atomic force micrograph of the cross section of the composite film is shown in Figure 7. The black areas are the rubber phase, which is dispersed, band-like, and aligned parallel to each other. The rubber phase had an average horizontal size of 53 nm and an average aspect ratio of 5.2.

[0372] Example E2 (1) Preparation of Propylene Polymer Composition A for Preparation of Layer a Component a was a propylene impact copolymer with the trade name F200R (available from Shanghai Petrochemical Co., Ltd.; the ethylene unit content was 9.1 wt %, the ethylene-propylene copolymer content was 12.2 wt %, the rubber phase had an average particle size of 800 nm, a maximum particle size of 1 μm, the ethylene unit content in the xylene soluble matter at room temperature was 38.1 wt %, the ethylene unit sequence [EEE] content was 13.6 wt %, and the melt flow rate was 2.1 g / 10 min); component b was a homopolypropylene with the trade name PPH-FA03 (available from Qingdao Refining & Chemical Co., Ltd.; the melt flow rate was 3.1 g / 10 min, and the molecular weight distribution Mw / Mn was 4.7); and component c was a polyolefin elastomer with the trade name 8200 (available from Dow; ethylene-1-octene copolymer). The various components prepared above were weighed and mixed in the following proportions: 75 parts by weight of component a (Wa), 10 parts by weight of component b (Wb), and 15 parts by weight of component c (Wc). A lubricant (a PEG lubricant manufactured by Clariant, Switzerland, with a molecular weight of 10,000, added in an amount of 0.1 parts by weight based on 100 parts by weight of the total mass of the above components a, b, and c) was then added, and the mixture was then mixed uniformly in a high-speed mixer. The mixed material was then added to the feeder of a twin-screw extruder manufactured by W&P. The material entered the twin screws, and the screw temperature was maintained in the range of 160-230°C during processing. The material was melt-mixed uniformly by the screws, extruded, pelletized, and dried. Pellets of propylene polymer composition A were obtained, and after measurement, they had a melt flow rate of MFR A =3.3g / 10min.

[0373] (2) Preparation of Propylene Polymer Composition B for Preparation of Layer b Component x was a propylene random copolymer with the trade name F5006 (available from Yanshan Petrochemical Co., Ltd., an ethylene-propylene-butene terpolymer with a melt flow rate of 5.2 g / 10 min); component y was a polyolefin elastomer with the trade name 8200 (available from Dow, an ethylene-1-octene copolymer). The various components prepared above were weighed and mixed according to the ratio of 75 parts by weight of component x (Wx) and 25 parts by weight of component y (Wy). The other procedures were the same as those in step (1). Finally, pellets of propylene polymer composition B were obtained, and after measurement, they were found to have a melt flow rate of MFR B =4.2g / 10min.

[0374] (3) Preparation of composite films The pellets of propylene polymer composition A and propylene polymer composition B obtained in steps (1) and (2) above were dried. Then, propylene polymer composition A was added to the core layer extruder of a multi-layer extrusion casting machine, and propylene polymer composition B was added to the top layer extruder of the multi-layer extrusion casting machine. An inorganic antiblocking agent (silica, the same as above) was added to the top layer extruder, and the weight ratio of the antiblocking agent to the propylene polymer composition pellets was 0.2:100. During the casting process, the temperature of the casting chill roll was set to 30°C. After winding, a composite film consisting of a top layer (layer b) and a core layer (layer a) was prepared. The film thickness was 50 μm, and the thickness ratio of layer b to layer a was 1:2.

[0375] Observation of the composite films under an atomic force microscope revealed that the rubber phases were dispersed, band-like, and aligned parallel to each other, with an average transverse size of 62 nm and an average aspect ratio of 11.2.

[0376] Example E3 Component a was a propylene impact copolymer with the trade name PPB-M02D (the rubber phase had an average particle size of 1.4 μm and a maximum particle size of 1.9 μm, available from Maoming Petrochemical Co., Ltd., an ethylene content of 8 wt%, an ethylene-propylene copolymer content of 10 wt%, an ethylene unit content in the xylene soluble matter at room temperature of 36.3 wt%, an ethylene unit sequence [EEE] content of 18.5 wt%, and a melt flow rate of 1.5 g / 10 min); component b was a propylene-ethylene binary random copolypropylene with the trade name F800EDF (available from Shanghai Petrochemical Co., Ltd., a melt flow rate of 7.8 g / 10 min); and component c was a polyolefin elastomer with the trade name VM3980 (available from Exxon Corporation, a propylene-ethylene copolymer). The various components prepared above were weighed and mixed in the following proportions: 55 parts by weight of component a (Wa), 25 parts by weight of component b (Wb), and 20 parts by weight of component c (Wc). A lubricant (PEG lubricant manufactured by Clariant, Switzerland, with a molecular weight of 10,000, added in an amount of 0.1 parts by weight based on 100 parts by weight of the total mass of the above components a, b, and c) was then added, and the mixture was then added to a high-speed mixer for homogeneous mixing. The mixed material was then added to the feeder of a twin-screw extruder manufactured by W&P. The material entered the twin screws, and the screw temperature was maintained in the range of 160-230°C during processing. The material was homogeneously melt-mixed, extruded, pelletized, and dried. Pellets of propylene polymer composition A were obtained, and after measurement, they had a melt flow rate of MFR A =6.4g / 10min.

[0377] (2) Preparation of Propylene Polymer Composition B for Preparation of Layer b Component x was a propylene random copolymer with the trade name F800EDF (available from Shanghai Petrochemical Co., a propylene-ethylene copolymer with a melt flow rate of 7.8 g / 10 min); component y was a polyolefin elastomer with the trade name VM3980 (available from Exxon, a propylene-ethylene copolymer). The various components prepared above were weighed and mixed according to the ratio of 80 parts by weight of component x (Wx) and 20 parts by weight of component y (Wy). The other procedures were the same as those in step (1). Finally, pellets of propylene polymer composition B were obtained, and after measurement, they were found to have a melt flow rate of MFR B =8.3g / 10min.

[0378] (3) Preparation of composite films The procedure was the same as that in step (3) of Example E1. The thickness of the final film was 50 μm, and the ratio of the total thickness of the upper and lower layers to the thickness of the core layer was 1:4.

[0379] Observation of the composite films under an atomic force microscope revealed that the rubber phases were dispersed, band-like, and aligned parallel to each other, with an average transverse size of 143 nm and an average aspect ratio of 8.7.

[0380] Example E4 (1) Preparation of Propylene Polymer Composition A for Preparation of Layer a The procedure was the same as in step (1) of Example E2, except that the parts by weight Wa of component a was 80 parts by weight, the parts by weight Wb of component b was 18 parts by weight, and the parts by weight Wc of component c was 2 parts by weight, and component c was a polyolefin elastomer with the trade name 8411 (available from Dow, ethylene-1-octene copolymer). Pellets of propylene polymer composition A were obtained, and after measurement, they had a melt flow rate MFR A =3.1g / 10min.

[0381] (2) Preparation of Propylene Polymer Composition B for Preparation of Layer b The procedure was the same as that in step (2) of Example E2, except that the parts by weight Wx of component x was 92 parts by weight and the parts by weight Wy of component y was 8 parts by weight. The other procedures were the same as those in step (1). Finally, pellets of propylene polymer composition B were obtained, and after measurement, they had a melt flow rate of MFR B =7.5g / 10min.

[0382] (3) Preparation of composite films The procedure was the same as that in step (3) of Example E2. The thickness of the film was 50 μm, and the thickness ratio of layer b to layer a was 1:6.

[0383] Observation of the composite films under an atomic force microscope revealed that the rubber phases were dispersed, band-like, and aligned parallel to each other, with an average transverse size of 77 nm and an average aspect ratio of 5.6.

[0384] Example E5 (1) Preparation of Propylene Polymer Composition A for Preparation of Layer a The procedure was the same as that in step (1) of Example E1, except that the parts by weight Wa of component a was 90 parts by weight, the parts by weight Wb of component b was 5 parts by weight, and the parts by weight Wc of component c was 5 parts by weight. Pellets of propylene polymer composition A were obtained, and after measurement, they had a melt flow rate MFR A =5.1g / 10min.

[0385] (2) Preparation of Propylene Polymer Composition B The procedure was the same as that in step (2) of Example E2, except that the parts by weight Wx of component x was 80 parts by weight and the parts by weight Wy of component y was 20 parts by weight. Finally, pellets of propylene polymer composition B were obtained, and after measurement, they had a melt flow rate of MFR B =3.5g / 10min.

[0386] (3) Preparation of composite films The procedure was the same as that in step (3) of Example E1. The film thickness was 50 μm, and the ratio of the total thickness of the upper and lower layers to the thickness of the core layer was 2:1.

[0387] Observation of the composite films under an atomic force microscope revealed that the rubber phases were dispersed, band-like, and aligned parallel to each other, with an average transverse size of 25 nm and an average aspect ratio of 14.6.

[0388] Example E6 (1) Preparation of Propylene Polymer Composition A for Preparation of Layer a The procedure was the same as that in step (1) of Example E3, except that the parts by weight Wa of component a was 50 parts by weight, the parts by weight Wb of component b was 40 parts by weight, and the parts by weight Wc of component c was 10 parts by weight. Pellets of propylene polymer composition A were obtained, and after measurement, they had a melt flow rate MFR A =2.3g / 10min.

[0389] (2) Preparation of Propylene Polymer Composition B for Preparation of Layer b The procedure was the same as that in step (2) of Example E3, except that the parts by weight Wx of component x was 60 parts by weight and the parts by weight Wy of component y was 40 parts by weight. Finally, pellets of propylene polymer composition B were obtained, and after measurement, they had a melt flow rate MFR B =9.6g / 10min.

[0390] (3) Preparation of composite films The procedure was the same as that in step (3) of Example E3.

[0391] Observation of the composite films under an atomic force microscope revealed that the rubber phases were dispersed, band-like, and aligned parallel to each other, with an average transverse size of 138 nm and an average aspect ratio of 6.3.

[0392] Example E7 (1) Preparation of Propylene Polymer Composition A for Preparation of Layer a The procedure was the same as that in step (1) of Example E2, except that the parts by weight Wa of component a was 50 parts by weight, the parts by weight Wb of component b was 20 parts by weight, and the parts by weight Wc of component c was 30 parts by weight. Pellets of propylene polymer composition A were obtained, and after measurement, they had a melt flow rate of MFR A =3.6g / 10min.

[0393] (2) Preparation of Propylene Polymer Composition B for Preparation of Layer b The procedure was the same as that in step (2) of Example E2, except that the parts by weight Wx of component x was 85 parts by weight and the parts by weight Wy of component y was 15 parts by weight. The other procedures were the same as those in step (1). Finally, pellets of propylene polymer composition B were obtained, and after measurement, they had a melt flow rate of MFR B =4.3g / 10min.

[0394] (3) Preparation of composite films The procedure was the same as that in step (3) of Example E2. The thickness of the film was 50 μm, and the thickness ratio of layer b to layer a was 1:3.

[0395] Observation of the composite film under an atomic force microscope revealed that the rubber phases were dispersed, band-like, and aligned parallel to each other, with an average transverse size of 106 nm and an average aspect ratio of 8.6.

[0396] Example E8 A composite film was prepared as described in Example E2, except that in the preparation of propylene polymer composition A, the parts by weight Wa of component a was 40 parts by weight, the parts by weight Wb of component b was 40 parts by weight, and the parts by weight Wc of component c was 20 parts by weight. Pellets of propylene polymer composition A were obtained and, after measurement, they had a melt flow rate of MFR A =3.3g / 10min.

[0397] The composite films were examined under an atomic force microscope and the rubber phases were found to be dispersed, band-like, and parallel to each other, with an average transverse size of 94 nm and an average aspect ratio of 9.3.

[0398] Example E9 A composite film was prepared as described in Example E2, except that in the preparation of propylene polymer composition B, the parts by weight Wx of component x was 95 parts by weight and the parts by weight Wy of component y was 5 parts by weight. Finally, pellets of propylene polymer composition B were obtained, and after measurement, they had a melt flow rate MFR B =5.5g / 10min.

[0399] [Example E10] A composite film was prepared as described in Example E2, except that in the preparation of propylene polymer composition B, the parts by weight Wx of component x was 70 parts by weight and the parts by weight Wy of component y was 30 parts by weight. Finally, pellets of propylene polymer composition B were obtained, and after measurement, they had a melt flow rate MFR B =4.7g / 10min.

[0400] [Example E11] A composite film was prepared as described in Example E2, except that in the preparation of propylene polymer composition B, the parts by weight Wx of component x was 40 parts by weight and the parts by weight Wy of component y was 60 parts by weight. Finally, pellets of propylene polymer composition B were obtained, and after measurement, they had a melt flow rate MFR B =3.2g / 10min.

[0401] [Comparative Example E1] A composite film was prepared as described in Example E2, except that in the preparation of propylene polymer composition A, the propylene impact copolymer was replaced with a propylene impact copolymer with the trade name F780R (available from Shanghai Petrochemical Co.; the rubber phase had an average particle size of 2.0 μm, a maximum particle size of 3.0 μm, an ethylene unit content of 9.0 wt %, an ethylene-propylene copolymer content of 17.1 wt %, and a melt flow rate of 7.3 g / 10 min; Figure 6b is an SEM photograph of the cross section of the propylene impact copolymer specimen). Finally, pellets of propylene polymer composition A were obtained, and after measurement, they had a melt flow rate of MFR A =7.7g / 10min.

[0402] [Example E12] A composite film was prepared as described in Example E2, except that propylene polymer composition A contained only component a and component b, the parts by weight Wa of component a was 75 parts by weight, and the parts by weight Wb of component b was 25 parts by weight.

[0403] [Comparative example E2] A composite film was prepared as described in Example E2, except that propylene polymer composition A contained only component a and component c, the parts by weight Wa of component a was 75 parts by weight, and the parts by weight Wc of component c was 25 parts by weight.

[0404] [Table 7]

[0405] From the results in Table 7, it can be concluded that the composite films having the microstructure according to the present invention simultaneously had good impact resistance and optical properties, and even had good heat seal strength. In contrast, the composite films not having the microstructure according to the present invention, which were prepared by using a propylene impact copolymer other than that according to the present invention, had poor optical properties or impact resistance, and during extrusion molding, the film surface was unstable, making it difficult to obtain a film with a uniform thickness.

[0406] Example F1 (1) Preparation of Propylene Polymer Composition A for Preparation of Layer a Component a was a homopolypropylene with the trade name PPH-FA03 (available from Qingdao Refining & Chemical Co., Ltd., having a melt flow rate of 3.1 g / 10 min, an isotacticity of 98%, and a molecular weight distribution Mw / Mn of 4.7); component b was a polyolefin elastomer with the trade name 8411 (available from Dow, an ethylene-1-octene copolymer). The various components prepared above were weighed and mixed in proportions such that component a (Wa) was 80 parts by weight and component b (Wb) was 20 parts by weight. Next, a lubricant (a PEG lubricant manufactured by Clariant, Switzerland, with a molecular weight of 10,000, added in an amount of 0.1 parts by weight based on 100 parts by weight of the total mass of the above-mentioned components a and b) was added, and the mixture was then added to a high-speed mixer to mix uniformly. The mixed material was then added to the feeder of a twin-screw extruder manufactured by W&P, and the material entered the twin screws. The screw temperature was maintained in the range of 160 to 230°C during processing, and the material was melt-mixed uniformly by the screws, extruded, pelletized, and dried. Pellets of propylene polymer composition A were obtained, and after measurement, they had a melt flow rate of MFR A =3.4g / 10min.

[0407] (2) Preparation of Propylene Polymer Composition B for Preparation of Layer b Component x was a propylene random copolymer with the trade name F5006 (available from Yanshan Petrochemical Co., Ltd., an ethylene-propylene-butene terpolymer with a melt flow rate of 5.2 g / 10 min); component y was a polyolefin elastomer with the trade name 8200 (available from Dow, an ethylene-1-octene copolymer); and component z was a polypropylene impact copolymer with the trade name PPB-M02D (the rubber phase had an average particle size of 1.4 μm and a maximum particle size of 1.9 μm, available from Maoming Petrochemical Co., Ltd., an ethylene content of 8 wt %, and a melt flow rate of 1.5 g / 10 min). The various components prepared above were weighed and mixed according to the following proportions: 85 parts by weight of component x (Wx), 5 parts by weight of component y (Wy), and 10 parts by weight of component z (Wz). The other steps are the same as those in step (1), and finally, pellets of propylene polymer composition B are obtained. After measurement, they have a melt flow rate of MFR B =4.8g / 10min.

[0408] (3) Preparation of composite films The pellets of propylene polymer composition A and propylene polymer composition B obtained in steps (1) and (2) above were dried. Then, propylene polymer composition A was added to the core layer extruder of a multi-layer extrusion casting machine, and propylene polymer composition B was added to the top layer extruder of the multi-layer extrusion casting machine. An inorganic antiblocking agent (silica, the same as above) was added to the top layer extruder, and the weight ratio of the antiblocking agent to the propylene polymer composition pellets was 0.2:100. During the casting process, the temperature of the casting chill roll was set to 30°C. After winding, a composite film consisting of a top layer (layer b) and a core layer (layer a) was prepared. The film thickness was 50 μm, and the thickness ratio of layer b to layer a was 1:2.

[0409] Atomic force micrographs of cross sections of the composite films showed that the rubber phase was uniformly dispersed in the film, in the form of bands, and arranged parallel to each other. The rubber phases had an average transverse size of 128 nm and an average aspect ratio of 5.2.

[0410] Example F2 (1) Preparation of propylene polymer composition A for the preparation of layer a: Component a was a propylene impact copolymer with the trade name F200R (available from Shanghai Petrochemical Co., Ltd.; the rubber phase had an average particle size of 800 nm, a maximum particle size of 1 μm, an ethylene content of 9.1 wt %, an ethylene-propylene copolymer content of 12.2 wt %, an ethylene unit content in the xylene soluble matter at room temperature of 38.1 wt %, an ethylene unit sequence [EEE] content of 13.6 wt %, and a melt flow rate of 2.1 g / 10 min); component b was a polyolefin elastomer with the trade name DF840 (available from Mitsui Co., Ltd.; an ethylene-1-butene copolymer). The various components prepared above were weighed and mixed in proportions such that component a (Wa) was 95 parts by weight and component b (Wb) was 5 parts by weight. Next, a lubricant (a PEG lubricant manufactured by Clariant, Switzerland, with a molecular weight of 10,000, added in an amount of 0.1 parts by weight based on 100 parts by weight of the total mass of the above-mentioned components a and b) was added, and the mixture was then added to a high-speed mixer to mix uniformly. The mixed material was then added to the feeder of a twin-screw extruder manufactured by W&P, and the material entered the twin screws. The screw temperature was maintained in the range of 160 to 230°C during processing, and the material was melt-mixed uniformly by the screws, extruded, pelletized, and dried. Pellets of propylene polymer composition A were obtained, and after measurement, they had a melt flow rate of MFR A =3.6g / 10min.

[0411] (2) Preparation of Propylene Polymer Composition B for Preparation of Layer b Component x was a propylene random copolymer with the trade name F500EPS (available from Shanghai Petrochemical Co., Ltd., an ethylene-propylene-butene terpolymer with a melt flow rate of 5.3 g / 10 min); component y was a polyolefin elastomer with the trade name DF840 (available from Mitsui); and component z was a polypropylene impact copolymer with the trade name F200R. The various components prepared above were weighed and mixed according to the ratio of 60 parts by weight of component x (Wx), 20 parts by weight of component y (Wy), and 20 parts by weight of component z (Wz). The other steps were the same as those in step (1). Finally, pellets of propylene polymer composition B were obtained, and after measurement, they were found to have a melt flow rate of MFR B =4.3g / 10min.

[0412] (3) Preparation of composite films The pellets of propylene polymer composition A and propylene polymer composition B obtained in steps (1) and (2) above were dried. Then, propylene polymer composition A was added to the core layer extruder of a multi-layer extrusion caster, and propylene polymer composition B was added to the top layer extruder and bottom layer extruder of the multi-layer extrusion caster. An inorganic antiblocking agent (silica, as described above) was added to the top layer extruder and bottom layer extruder, with the weight ratio of the antiblocking agent to the propylene polymer composition pellets being 0.2:100. During the film casting process, the temperature of the casting chill roll was set to 30°C. After winding, a composite film consisting of the top layer, the bottom layer (layer b) and the core layer (layer a) was prepared. The film thickness was 50 μm, and the ratio of the total thickness of the top layer and the bottom layer to the thickness of the core layer was 1:1.

[0413] Observation of the composite film under an atomic force microscope revealed that the rubber phases were dispersed, band-like, and aligned parallel to each other, with an average transverse size of 88 nm and an average aspect ratio of 7.5.

[0414] Example F3 (1) Preparation of Propylene Polymer Composition A for Preparation of Layer a Component a was a homopolypropylene with the trade name FC801 (available from Shanghai Petrochemical Co., Ltd., having a melt flow rate of 7.8 g / 10 min, an isotacticity of 98%, and a molecular weight distribution Mw / Mn of 4.8); component b was a polyolefin elastomer with the trade name VM3980 (available from Exxon Corporation, a propylene-ethylene copolymer with an ethylene structural unit content of 9% by weight). The various components prepared above were weighed and mixed in a ratio of 85 parts by weight of component a (Wa) and 15 parts by weight of component b (Wb). Next, a lubricant (a PEG lubricant manufactured by Clariant, Switzerland, with a molecular weight of 10,000, added in an amount of 0.1 parts by weight based on 100 parts by weight of the total mass of the above-mentioned components a and b) was added, and the mixture was then added to a high-speed mixer to mix uniformly. The mixed material was then added to the feeder of a twin-screw extruder manufactured by W&P, and the material entered the twin screws. The screw temperature was maintained in the range of 160 to 230°C during processing, and the material was melt-mixed uniformly by the screws, extruded, pelletized, and dried. Pellets of propylene polymer composition A were obtained, and after measurement, they had a melt flow rate of MFR A =7.4g / 10min.

[0415] (2) Preparation of Propylene Polymer Composition B for Preparation of Layer b Component x was a propylene random copolymer with the trade name F800EPS (available from Shanghai Petrochemical Co., Ltd., an ethylene-propylene-butene terpolymer with a melt flow rate of 8.2 g / 10 min); component y was a polyolefin elastomer with the trade name VM3980 (available from Exxon, a propylene-ethylene copolymer with an ethylene structural unit content of 9 wt%); and component z was a polypropylene impact copolymer with the trade name J410F (available from Hyosung, Korea, the rubber phase had an average particle size of 600 nm, a maximum particle size of 800 nm, an ethylene content of 5.3 wt%, an ethylene-propylene copolymer content of 7.2 wt%, an ethylene unit content in the xylene soluble matter at room temperature of 26.0 wt%, an ethylene unit sequence [EEE] content of 6.9 wt%, and a melt flow rate of 4.6 g / 10 min). The various components prepared above were weighed and mixed according to the ratio of 85 parts by weight of component x (Wx), 10 parts by weight of component y (Wy), and 5 parts by weight of component z (Wz). The other steps were the same as those in step (1). Finally, pellets of propylene polymer composition B were obtained, and after measurement, they had a melt flow rate of MFR B =8.4g / 10min.

[0416] (3) Preparation of composite films The preparation procedure was the same as step (3) in Example F1.

[0417] Observation of the composite films under an atomic force microscope revealed that the rubber phases were dispersed, band-like, and aligned parallel to each other, with an average transverse size of 54 nm and an average aspect ratio of 9.8.

[0418] Example F4 (1) Preparation of Propylene Polymer Composition A for Preparation of Layer a The procedure was the same as that in step (1) of Example F1, except that the parts by weight Wa of component a was 70 parts by weight and the parts by weight Wb of component b was 30 parts by weight. Pellets of propylene polymer composition A were obtained and, after measurement, they had a melt flow rate MFR A =3.5g / 10min.

[0419] (2) Preparation of Propylene Polymer Composition B for Preparation of Layer b The process was the same as step (2) of Example F1, except that the parts by weight Wx of component x was 90 parts by weight, the parts by weight Wy of component y was 5 parts by weight, and the parts by weight Wz of component z was 5 parts by weight. The other procedures were the same as those in step (1). Finally, pellets of propylene polymer composition B were obtained, and after measurement, they had a melt flow rate of MFR B =5.5g / 10min.

[0420] (3) Preparation of composite films The process was the same as that in Example F1. The film thickness was 50 μm, and the thickness ratio of Layer B to Layer A was 1:3.

[0421] Example F5 (1) Preparation of Propylene Polymer Composition A for Preparation of Layer a The procedure was the same as that in step (1) of Example F2, except that the parts by weight Wa of component a was 75 parts by weight and the parts by weight Wb of component b was 25 parts by weight. Pellets of propylene polymer composition A were obtained and, after measurement, they had a melt flow rate MFR A =4.0g / 10min.

[0422] (2) Preparation of Propylene Polymer Composition B for Preparation of Layer b The procedure was the same as that in Example F3, except that the parts by weight Wx of component x was 85 parts by weight, the parts by weight Wy of component y was 13 parts by weight, and the parts by weight Wz of component z was 2 parts by weight. Finally, pellets of propylene polymer composition B were obtained, and after measurement, they had a melt flow rate MFR B=8.2g / 10min.

[0423] (3) Preparation of composite films The procedure was the same as that in Example F2. The film thickness was 50 μm, and the ratio of the total thickness of the top and bottom layers to the thickness of the core layer was 2:1.

[0424] Example F6 (1) Preparation of Propylene Polymer Composition A for Preparation of Layer a The procedure was the same as that in step (1) of Example F3.

[0425] (2) Preparation of Propylene Polymer Composition B for Preparation of Layer b The procedure was the same as that in step (2) of Example F3, except that the parts by weight Wx of component x was 50 parts by weight, the parts by weight Wy of component y was 30 parts by weight, component y was a polyolefin elastomer with the trade name 8411 (ethylene-1-octene copolymer, available from Dow), and the parts by weight Wz of component z was 20 parts by weight. Finally, pellets of propylene polymer composition B were obtained, and after measurement, they had a melt flow rate MFR B =8.6g / 10min.

[0426] (3) Preparation of composite films The procedure was the same as that in step (3) of Example F3. The thickness of the film was 50 μm, and the ratio of the thickness of the top layer to the thickness of the core layer was 1:4.

[0427] Observation of the composite films under an atomic force microscope revealed that the rubber phases were dispersed, band-like, and aligned parallel to each other, with an average transverse size of 28 nm and an average aspect ratio of 14.5.

[0428] Example F7 (1) Preparation of Propylene Polymer Composition A for Preparation of Layer a The procedure was the same as that in step (1) of Example F1.

[0429] (2) Preparation of Propylene Polymer Composition B for Preparation of Layer b The procedure was the same as that in step (2) of Example F1, except that the parts by weight Wx of component x was 50 parts by weight, the parts by weight Wy of component y was 20 parts by weight, and the parts by weight Wz of component z was 30 parts by weight. The other procedures were the same as those in step (1). Finally, pellets of propylene polymer composition B were obtained, and after measurement, the melt flow rate was MFR B =4.3g / 10min.

[0430] (3) Preparation of composite films The procedure was the same as that in step (3) of Example F1. The thickness of the film was 50 μm, and the thickness ratio of Layer B to Layer A was 1:3.

[0431] Observation of the composite films under an atomic force microscope revealed that the rubber phases were dispersed, band-like, and aligned parallel to each other, with an average transverse size of 147 nm and an average aspect ratio of 6.3.

[0432] Example F8 A composite film was prepared as described in Example F1, except that in the preparation of propylene polymer composition A, the mass parts Wa of component a was 50 parts by weight and the mass parts Wb of component b was 50 parts by weight. Finally, pellets of propylene polymer composition A were obtained, and after measurement, they had a melt flow rate of MFR A =3.6g / 10min.

[0433] The composite films were examined under an atomic force microscope and the rubber phases were found to be dispersed, band-like, and parallel to each other, with an average transverse size of 120 nm and an average aspect ratio of 5.5.

[0434] Example F9 A composite film was prepared as described in Example F1, except that in the preparation of propylene polymer composition B, the parts by weight Wx of component x was 40 parts by weight, the parts by weight Wy of component y was 30 parts by weight, and the parts by weight Wz of component z was 30 parts by weight. Pellets of propylene polymer composition B were obtained and, after measurement, they had a melt flow rate MFR B =4.2g / 10min.

[0435] Observation of the composite film under an atomic force microscope revealed that the rubber phases were dispersed, band-like, and aligned parallel to each other, with an average transverse size of 145 nm and an average aspect ratio of 7.4.

[0436] Example F10 A composite film was prepared as described in Example F1, except that in the preparation of propylene polymer composition B, the parts by weight Wx of component x was 50 parts by weight, the parts by weight Wy of component y was 40 parts by weight, and the parts by weight Wz of component z was 10 parts by weight. Pellets of propylene polymer composition B were obtained and, after measurement, they had a melt flow rate MFR B =5.3g / 10min.

[0437] Observation of the composite film under an atomic force microscope revealed that the rubber phases were dispersed, band-like, and aligned parallel to each other, with an average transverse size of 102 nm and an average aspect ratio of 9.3.

[0438] [Comparative Example F1] A composite film was prepared as described in Example F1, except that in the preparation of propylene polymer composition B, polypropylene impact copolymer z was replaced with a polypropylene impact copolymer with the trade name F780R (available from Shanghai Petrochemical Co., the rubber phase has an average particle size of 2.0 μm, a maximum particle size of 3.0 μm, an ethylene unit content of 9.0 wt%, an ethylene-propylene copolymer content of 17.1 wt%, and a melt flow rate of 7.3 g / 10 min). Finally, pellets of propylene polymer composition B were obtained, and after measurement, they had a melt flow rate of MFR B =7.9 g / 10 min. The film thickness was 50 μm.

[0439] [Comparative Example F2] A composite film was prepared as described in Example F2, except that component a in composition A and component z in composition B were replaced with a propylene impact copolymer under the trade name F780R, and pellets of propylene polymer composition A (melt flow rate MFR A =7.3g / 10min) and pellets of propylene polymer composition B (Melt flow rate MFR B = 6.5 g / 10 min) The film thickness was 50 μm.

[0440] [Comparative Example F3] A composite film was prepared as described in Example F1, except that propylene polymer composition B contained only component x.

[0441] [Comparative Example F4] A composite film was prepared as described in Example F1, except that propylene polymer composition B contained only component x and component y, the parts by weight Wx of component x was 85 parts by weight, and the parts by weight Wy of component y was 15 parts by weight.

[0442] [Comparative Example F5] A composite film was prepared as described in Example F2, except that propylene polymer composition B contained only component x and component z, the parts by weight Wx of component x was 70 parts by weight, and the parts by weight Wz of component z was 30 parts by weight.

[0443] [Table 8]

[0444] From the results in Table 8, it can be concluded that the composite films having the microstructure of the present invention prepared using the propylene impact copolymer of the present invention simultaneously possessed both good impact resistance and optical properties, as well as good tensile properties and good heat seal strength. In contrast, the composite films not having the microstructure of the present invention prepared using the propylene impact copolymer of the present invention had poor optical properties or impact resistance, as well as poor tensile properties or heat seal strength; furthermore, the film surface was unstable during extrusion molding, making it difficult to obtain a film with a uniform thickness.

[0445] Example G1 (Maleic anhydride-modified polypropylene) (1) Preparation of Propylene Polymer Composition A for Preparation of Layer a Component a was homopolypropylene with the trade name PPH-FA03 (available from Qingdao Refining & Chemical Co., Ltd., melt flow rate 3.1 g / 10 min, isotacticity 98%, molecular weight distribution Mw / Mn 4.7). Component b was propylene impact copolymer with the trade name EP200K (available from SINOPEC SABIC Petrochemical Company, ethylene content 8 wt %, melt flow rate 3.2 g / 10 min). Component c was polyolefin elastomer with the trade name 6102 (available from Exxon Corporation, ethylene-propylene copolymer). The various components prepared above were weighed and mixed according to the following proportions: 75 parts by weight of component a (Wa), 10 parts by weight of component b (Wb), and 15 parts by weight of component c (Wc). Next, a lubricant (PEG lubricant FL7540L manufactured by Clariant, Switzerland, molecular weight 10,000, added at 0.1 parts by weight based on 100 parts by weight of the total mass of the above components a, b, and c) was added, and the mixture was then added to a high-speed mixer and mixed uniformly. The mixed material was then added to the feeder of a twin-screw extruder manufactured by W&P, and the material was fed into the twin screws, the screw temperature of which was maintained in the range of 160-230°C during processing. The material was melt-mixed uniformly by the screws, extruded, pelletized, and dried. Pellets of propylene polymer composition A were obtained, and after measurement, the pellets had a melt flow rate (MFR A = 3.6 g / 10 min.

[0446] (2) Preparation of Propylene Polymer Composition B for Preparation of Layer b Component x was a propylene random copolymer with the trade name F5006 (available from Yanshan Petrochemical Company, an ethylene-propylene-butene terpolymer with a melt flow rate of 5.2 g / 10 min). Component y was a polyolefin elastomer with the trade name 6102 (available from Exxon Corporation, an ethylene-propylene copolymer). Component z was a maleic anhydride-modified polypropylene with the trade name QF551A (available from Mitsui). The various components prepared above were weighed and mixed according to the following ratios: 70 parts by weight of component x (Wx), 15 parts by weight of component y (Wy), and 15 parts by weight of component z (Wz). The Wc:Wy ratio was 1:1. The other steps were the same as in step (1), and pellets of propylene polymer composition B were finally obtained. After measurement, the pellets had a melt flow rate MFR B = 3.5g / 10min.

[0447] (3) Preparation of composite films After drying the pellets of propylene polymer composition A and propylene polymer composition B obtained in steps (1) and (2) above, propylene polymer composition A was added to the core layer extruder of a multi-layer extrusion casting machine, propylene polymer composition B was added to the top layer extruder of the multi-layer extrusion casting machine, and an inorganic antiblocking agent (silica, as described above) was added to the top layer extruder, with the weight ratio of the antiblocking agent to the propylene polymer composition pellets being 0.2:100. During the casting process, the temperature of the casting quench roll was set to 30°C. After winding, a composite film consisting of a top layer (layer b) and a core layer (layer a) was prepared. The thickness of the composite film was 50 μm, and the thickness ratio of layer b to layer a was 1:2.

[0448] The composite films were observed under an atomic force microscope to visualize the rubber phase, which had an average horizontal size of 65 nm and an average aspect ratio of 10.9.

[0449] Example G2 (Polypropylene-g-glycidyl methacrylate used) I. Preparation of Polypropylene-g-Glycidyl Methacrylate A base copolypropylene powder was selected with the following characteristics: comonomer ethylene content of 18.1 wt%, xylene solubles content of 48.7 wt%, comonomer content in the solubles of 31.9 wt%, solubles / copolypropylene intrinsic viscosity ratio of 0.89, and weight average molecular weight of 34.3 × 10 4 The MFR was 1.21 g / 10 min under a 2.16 kg load at 230 °C, and Tm = 143.4 °C. Fine powders smaller than 40 mesh were removed by sieving. 2.0 kg of the above base copolypropylene powder was weighed and added to a 10 L reactor with mechanical stirring. The reaction system was sealed and purged with nitrogen to remove oxygen. 2.5 g of dibenzoyl peroxide and 80 g of glycidyl methacrylate were added, and the materials were stirred and mixed for 30 minutes, then heated to 90 °C and reacted for 4 hours. After the reaction was completed, a nitrogen purge was performed and the temperature was reduced to obtain polypropylene-g-glycidyl methacrylate with a melt flow rate of 0.49 g / 10 min. The M1 was 2.96%, and the grafting efficiency was 77%.

[0450] (II. Preparation of Composite Film) (1) Preparation of Propylene Polymer Composition A for Preparation of Layer a Component a was homopolypropylene with the trade name PPH-FA03 (available from Qingdao Refining & Chemical Co., Ltd., melt flow rate 3.1 g / 10 min, isotacticity 98%, molecular weight distribution Mw / Mn 4.7). Component b was polypropylene-g-glycidyl methacrylate prepared above. Component c was polyolefin elastomer with the trade name 6102 (available from Exxon Corporation, ethylene-propylene copolymer). The various components prepared above were weighed and mixed according to the following proportions: 75 parts by weight of component a (Wa), 10 parts by weight of component b (Wb), and 15 parts by weight of component c (Wc). Next, a lubricant (PEG lubricant manufactured by Clariant, Switzerland, molecular weight 10,000, added at 0.1 parts by weight based on 100 parts by weight of the total mass of the above components a, b, and c) was added, and the mixture was then added to a high-speed mixer and mixed uniformly. The mixed material was then added to the feeder of a twin-screw extruder manufactured by W&P, and the material was fed into the twin screws, the screw temperature of which was maintained in the range of 160-230°C during processing. The material was melt-mixed uniformly by the screw, extruded, pelletized, and dried. Pellets of propylene polymer composition A were obtained, and after measurement, the pellets had a melt flow rate (MFR A = 2.8 g / 10 min.

[0451] (2) Preparation of Propylene Polymer Composition B for Preparation of Layer b Component x was a propylene random copolymer with the trade name F5006 (available from Yanshan Petrochemical Company, an ethylene-propylene-butene terpolymer with a melt flow rate of 5.2 g / 10 min). Component y was a polyolefin elastomer with the trade name 6102 (available from Exxon Corporation, an ethylene-propylene copolymer). The various components prepared above were weighed and mixed in a ratio of 75 parts by weight of component x (Wx) and 25 parts by weight of component y (Wy). The Wc:Wy ratio was 3:5. The other steps were the same as in step (1), and pellets of propylene polymer composition B were finally obtained. After measurement, the pellets had a melt flow rate MFR B = 3.2 g / 10 min.

[0452] (3) Preparation of composite films After drying the pellets of propylene polymer composition A and propylene polymer composition B obtained in steps (1) and (2) above, propylene polymer composition A was added to the core layer extruder of a multi-layer extrusion casting machine, propylene polymer composition B was added to the top layer extruder of the multi-layer extrusion casting machine, and an inorganic antiblocking agent (silica, as described above) was added to the top layer extruder, with the weight ratio of the antiblocking agent to the propylene polymer composition pellets being 0.2:100. During the casting process, the temperature of the casting quench roll was set to 30°C. After winding, a composite film consisting of a top layer (layer b) and a core layer (layer a) was prepared. The thickness of the composite film was 50 μm, and the thickness ratio of layer b to layer a was 1:2.

[0453] Example G3 (Polypropylene-g-styrene) I. Preparation of Polypropylene-g-Styrene A base copolypropylene powder was selected with the following characteristics: comonomer ethylene content of 18.1 wt%, xylene solubles content of 48.7 wt%, comonomer content in the solubles of 31.9 wt%, solubles / copolypropylene intrinsic viscosity ratio of 0.89, and weight average molecular weight of 34.3 × 10 4The polymer had a 1.21 g / mol MFR under a 2.16 kg load at 230°C and a Tm of 143.4°C. Fine powder smaller than 40 mesh was removed by sieving. 2.0 kg of the base copolypropylene powder was weighed and added to a 10 L reactor with mechanical stirring. The reaction system was sealed and purged with nitrogen to remove oxygen. 2 g of dibenzoyl peroxide and 100 g of styrene were added, and the materials were stirred and mixed for 60 minutes and then swelled at 40°C for 4 hours. The mixture was then heated to 95°C and reacted for 4 hours. After the reaction was completed, the mixture was purged with nitrogen and the temperature was reduced to obtain polypropylene-g-styrene with a melt flow rate of 0.75 g / 10 min. The M1 was 2.91% and the grafting efficiency was 61%.

[0454] (II. Preparation of Composite Film) (1) Preparation of Propylene Polymer Composition A for Preparation of Layer a Component a was homopolypropylene with the trade name PPH-FA03 (available from Qingdao Refining & Chemical Co., Ltd., melt flow rate 3.1 g / 10 min, isotacticity 98%, molecular weight distribution Mw / Mn 4.7). Component b was the polypropylene-g-styrene prepared above. Component c was a polyolefin elastomer with the trade name 6102 (available from Exxon Corporation, ethylene-propylene copolymer). The various components prepared above were weighed and mixed according to the following ratios: 75 parts by weight of component a (Wa), 10 parts by weight of component b (Wb), and 15 parts by weight of component c (Wc). Next, a lubricant (PEG lubricant manufactured by Clariant, Switzerland, molecular weight 10,000, 0.1 parts by weight added based on 100 parts by weight of the total mass of components a, b, and c) was added, and the mixture was added to a high-speed mixer and mixed uniformly. The mixed material was then added to the feeder of a twin-screw extruder manufactured by W&P, and the material was fed into the twin-screw, the temperature of which was maintained in the range of 160 to 230°C during processing. The material was uniformly melt-mixed by the screw, extruded, pelletized, and dried. Pellets of propylene polymer composition A were obtained, and after measurement, the pellets had a melt flow rate MFR A = 2.9 g / 10 min.

[0455] (2) Preparation of Propylene Polymer Composition B for Preparation of Layer b Component x was a propylene random copolymer with the trade name F5006 (available from Yanshan Petrochemical Company, an ethylene-propylene-butene terpolymer with a melt flow rate of 5.2 g / 10 min). Component y was a polyolefin elastomer with the trade name 6102 (available from Exxon Corporation, an ethylene-propylene copolymer). The various components prepared above were weighed and mixed in a ratio of 75 parts by weight of component x (Wx) and 25 parts by weight of component y (Wy). The Wc:Wy ratio was 3:5. The other steps were the same as in step (1), and pellets of propylene polymer composition B were finally obtained. After measurement, the pellets had a melt flow rate MFR B = 3.2 g / 10 min.

[0456] (3) Preparation of composite films After drying the pellets of propylene polymer composition A and propylene polymer composition B obtained in steps (1) and (2) above, propylene polymer composition A was added to the core layer extruder of a multi-layer extrusion casting machine, propylene polymer composition B was added to the top layer extruder of the multi-layer extrusion casting machine, and an inorganic antiblocking agent (silica, as described above) was added to the top layer extruder, with the weight ratio of the antiblocking agent to the propylene polymer composition pellets being 0.2:100. During the casting process, the temperature of the casting quench roll was set to 30°C. After winding, a composite film consisting of a top layer (layer b) and a core layer (layer a) was prepared. The thickness of the composite film was 50 μm, and the thickness ratio of layer b to layer a was 1:2.

[0457] Example G4 (using polypropylene-g-vinyltriethoxysilane) I. Preparation of Polypropylene-g-Vinyltriethoxysilane A base copolypropylene powder was selected with the following characteristics: comonomer ethylene content of 18.1 wt%, xylene solubles content of 48.7 wt%, comonomer content in the solubles of 31.9 wt%, solubles / copolypropylene intrinsic viscosity ratio of 0.89, and weight average molecular weight of 34.3 × 10 4g / mol, MFR of 1.21 g / 10 min under a 2.16 kg load at 230 °C, and Tm = 143.4 °C. Fine powder smaller than 40 mesh was removed by sieving. 2.0 kg of the above base copolypropylene powder was weighed and added to a 10 L reactor with mechanical stirring. The reaction system was sealed and purged with nitrogen to remove oxygen. 2.5 g of lauroyl peroxide and 50 g of vinyltriethoxysilane were added, and the materials were stirred and mixed for 30 minutes and then swelled at 40 °C for 1 hour. The mixture was then heated to 90 °C and reacted for 4 hours. After the reaction was completed, the mixture was cooled with nitrogen purging to reduce the temperature, yielding polypropylene-g-vinyltriethoxysilane with a melt flow rate of 1.15 g / 10 min. M1 was 1.03% and the grafting efficiency was 42%.

[0458] (II. Preparation of Composite Film) (1) Preparation of Propylene Polymer Composition A for Preparation of Layer a Component a was homopolypropylene with the trade name PPH-FA03 (available from Qingdao Refining & Chemical Co., Ltd., melt flow rate 3.1 g / 10 min, isotacticity 98%, molecular weight distribution Mw / Mn 4.7). Component b was polypropylene-g-vinyltriethoxysilane prepared above. Component c was polyolefin elastomer with the trade name 6102 (available from Exxon Corporation, ethylene-propylene copolymer). The various components prepared above were weighed and mixed according to the following proportions: 75 parts by weight of component a (Wa), 10 parts by weight of component b (Wb), and 15 parts by weight of component c (Wc). Next, a lubricant (PEG lubricant manufactured by Clariant, Switzerland, molecular weight 10,000, added at 0.1 parts by weight based on 100 parts by weight of the total mass of the above components a, b, and c) was added, and the mixture was then added to a high-speed mixer and mixed uniformly. The mixed material was then added to the feeder of a twin-screw extruder manufactured by W&P, and the material was fed into the twin screws, the screw temperature of which was maintained in the range of 160-230°C during processing. The material was melt-mixed uniformly by the screw, extruded, pelletized, and dried. Pellets of propylene polymer composition A were obtained, and after measurement, the pellets had a melt flow rate (MFR A = 3.0 g / 10 min.

[0459] (2) Preparation of Propylene Polymer Composition B for Preparation of Layer b Component x was a propylene random copolymer with the trade name F5006 (available from Yanshan Petrochemical Company, an ethylene-propylene-butene terpolymer with a melt flow rate of 5.2 g / 10 min). Component y was a polyolefin elastomer with the trade name 6102 (available from Exxon Corporation, an ethylene-propylene copolymer). The various components prepared above were weighed and mixed in a ratio of 75 parts by weight of component x (Wx) and 25 parts by weight of component y (Wy). The Wc:Wy ratio was 3:5. The other steps were the same as in step (1), and pellets of propylene polymer composition B were finally obtained. After measurement, the pellets had a melt flow rate MFR B = 3.2 g / 10 min.

[0460] (3) Preparation of composite films After drying the pellets of propylene polymer composition A and propylene polymer composition B obtained in steps (1) and (2) above, propylene polymer composition A was added to the core layer extruder of a multi-layer extrusion casting machine, propylene polymer composition B was added to the top layer extruder of the multi-layer extrusion casting machine, and an inorganic antiblocking agent (silica, as described above) was added to the top layer extruder, with the weight ratio of the antiblocking agent to the propylene polymer composition pellets being 0.2:100. During the casting process, the temperature of the casting quench roll was set to 30°C. After winding, a composite film consisting of a top layer (layer b) and a core layer (layer a) was prepared. The thickness of the composite film was 50 μm, and the thickness ratio of layer b to layer a was 1:2.

[0461] Example G5 (using polypropylene-g-4-vinylpyridine) I. Preparation of Polypropylene-g-4-Vinylpyridine A base copolypropylene powder was selected with the following characteristics: comonomer ethylene content of 18.1 wt%, xylene solubles content of 48.7 wt%, comonomer content in the solubles of 31.9 wt%, solubles / copolypropylene intrinsic viscosity ratio of 0.89, and weight average molecular weight of 34.3 × 10 4The MFR was 1.21 g / 10 min under a 2.16 kg load at 230 °C, and Tm = 143.4 °C. Fine powders smaller than 40 mesh were removed by sieving. 2.0 kg of the above base copolypropylene powder was weighed and added to a 10 L reactor with mechanical stirring. The reaction system was sealed and purged with nitrogen to remove oxygen. 1.2 g of dibenzoyl peroxide and 40 g of 4-vinylpyridine were added, and the materials were stirred and mixed for 30 minutes and then swelled at 50 °C for 30 minutes. The mixture was then heated to 90 °C and reacted for 4 hours. After the reaction was completed, the mixture was cooled under nitrogen purging to reduce the temperature, yielding polypropylene-g-4-vinylpyridine with a melt flow rate of 0.89 g / 10 min. The M1 was 0.92% and the grafting efficiency was 47%.

[0462] (II. Preparation of Composite Film) (1) Preparation of Propylene Polymer Composition A Component a was homopolypropylene with the trade name PPH-FA03 (available from Qingdao Refining & Chemical Co., Ltd., melt flow rate 3.1 g / 10 min, isotacticity 98%, molecular weight distribution Mw / Mn 4.7). Component b was polypropylene-g-4-vinylpyridine prepared above. Component c was polyolefin elastomer with the trade name 6102 (available from Exxon Corporation, ethylene-propylene copolymer). The various components prepared above were weighed and mixed according to the following proportions: 75 parts by weight of component a (Wa), 10 parts by weight of component b (Wb), and 15 parts by weight of component c (Wc). Next, a lubricant (PEG lubricant manufactured by Clariant, Switzerland, molecular weight 10,000, added at 0.1 parts by weight based on 100 parts by weight of the total mass of the above components a, b, and c) was added, and the mixture was then added to a high-speed mixer and mixed uniformly. The mixed material was then added to the feeder of a twin-screw extruder manufactured by W&P, and the material was fed into the twin screws, the screw temperature of which was maintained in the range of 160-230°C during processing. The material was melt-mixed uniformly by the screw, extruded, pelletized, and dried. Pellets of propylene polymer composition A were obtained, and after measurement, the pellets had a melt flow rate (MFR A = 3.1 g / 10 min.

[0463] (2) Preparation of Propylene Polymer Composition B Component x was a propylene random copolymer with the trade name F5006 (available from Yanshan Petrochemical Company, an ethylene-propylene-butene terpolymer with a melt flow rate of 5.2 g / 10 min). Component y was a polyolefin elastomer with the trade name 6102 (available from Exxon Corporation, an ethylene-propylene copolymer). The various components prepared above were weighed and mixed in a ratio of 75 parts by weight of component x (Wx) and 25 parts by weight of component y (Wy). The Wc:Wy ratio was 3:5. The other steps were the same as in step (1), and pellets of propylene polymer composition B were finally obtained. After measurement, the pellets had a melt flow rate MFR B = 3.2 g / 10 min.

[0464] (3) Preparation of composite films After drying the pellets of propylene polymer composition A and propylene polymer composition B obtained in steps (1) and (2) above, propylene polymer composition A was added to the core layer extruder of a multi-layer extrusion casting machine, propylene polymer composition B was added to the top layer extruder of the multi-layer extrusion casting machine, and an inorganic antiblocking agent (silica, as described above) was added to the top layer extruder, with the weight ratio of the antiblocking agent to the propylene polymer composition pellets being 0.2:100. During the casting process, the temperature of the casting quench roll was set to 30°C. After winding, a composite film consisting of a top layer (layer b) and a core layer (layer a) was prepared. The thickness of the composite film was 50 μm, and the thickness ratio of layer b to layer a was 1:2.

[0465] Example G6 (using polypropylene-g-styrene prepared in Example G3) (1) Preparation of Propylene Polymer Composition A for Preparation of Layer a Component a was homopolypropylene with the trade name PPH-FA03 (available from Qingdao Refining & Chemical Co., Ltd., melt flow rate 3.1 g / 10 min, isotacticity 98%, molecular weight distribution Mw / Mn 4.7). Component b was polyolefin elastomer with the trade name 6102 (available from Exxon Corporation, ethylene-propylene copolymer). The various components prepared above were weighed and mixed according to the ratio of 80 parts by weight of component a (Wa) and 20 parts by weight of component b (Wb). Next, a lubricant (PEG lubricant manufactured by Clariant, Switzerland, molecular weight 10,000, 0.1 parts by weight added based on 100 parts by weight of the total mass of components a and b) was added, and the mixture was added to a high-speed mixer and mixed uniformly. The mixed material was then added to the feeder of a twin-screw extruder manufactured by W&P, and the material was fed into the twin-screw, the temperature of which was maintained in the range of 160 to 230°C during processing. The material was uniformly melt-mixed by the screw, extruded, pelletized, and dried. Pellets of propylene polymer composition A were obtained, and after measurement, the pellets had a melt flow rate MFR A = 3.5g / 10min.

[0466] (2) Preparation of Propylene Polymer Composition B for Preparation of Layer b Component x was a propylene random copolymer with the trade name F5006 (available from Yanshan Petrochemical Company, an ethylene-propylene-butene terpolymer with a melt flow rate of 5.2 g / 10 min). Component y was a polyolefin elastomer with the trade name 6102 (available from Exxon Corporation, an ethylene-propylene copolymer). Component z was the polypropylene-g-styrene prepared in Example G3. The various components prepared above were weighed and mixed according to the following ratios: 85 parts by weight of component x (Wx), 5 parts by weight of component y (Wy), and 10 parts by weight of component z. The Wb:Wy ratio was 4:1. The other steps were the same as in step (1), and pellets of propylene polymer composition B were finally obtained. After measurement, the pellets had a melt flow rate MFR B = 4.64 g / 10 min.

[0467] (3) Preparation of composite films After drying the pellets of propylene polymer composition A and propylene polymer composition B obtained in steps (1) and (2) above, propylene polymer composition A was added to the core layer extruder of a multi-layer extrusion casting machine, propylene polymer composition B was added to the top layer extruder of the multi-layer extrusion casting machine, and an inorganic antiblocking agent (silica, as described above) was added to the top layer extruder, with the weight ratio of the antiblocking agent to the propylene polymer composition pellets being 0.2:100. During the casting process, the temperature of the casting quench roll was set to 30°C. After winding, a composite film consisting of a top layer (layer b) and a core layer (layer a) was prepared. The thickness of the composite film was 50 μm, and the thickness ratio of layer b to layer a was 1:2.

[0468] Example G7 (Polypropylene-g-styrene / Maleic Anhydride) I. Preparation of Polypropylene-g-Styrene / Maleic Anhydride A base copolypropylene powder was selected with the following characteristics: comonomer ethylene content of 18.1 wt%, xylene solubles content of 48.7 wt%, comonomer content in the solubles of 31.9 wt%, solubles / copolypropylene intrinsic viscosity ratio of 0.89, and weight average molecular weight of 34.3 × 10 4 The polymer had a melt flow rate of 1.21 g / mol under a 2.16 kg load at 230°C, a melt flow rate of 1.21 g / 10 min under a 2.16 kg load, and a temperature of 143.4°C. Fine powder smaller than 40 mesh was removed by sieving. 2.0 kg of the base copolypropylene powder was weighed and added to a 10 L reactor with mechanical stirring. The reaction system was sealed and purged with nitrogen to remove oxygen. 1.3 g of liquid dibenzoyl peroxide, 10 g of maleic anhydride, and 40 g of styrene were added, and the materials were stirred and mixed for 30 minutes and allowed to swell at 40°C for 2 hours. The mixture was then heated to 90°C and reacted for 4 hours. After the reaction was completed, the mixture was cooled under nitrogen purging to reduce the temperature, yielding polypropylene-g-styrene / maleic anhydride with a melt flow rate of 0.71 g / 10 min. The M1 was 1.27%, the M2 was 0.44%, and the grafting efficiency was 52%.

[0469] (II. Preparation of Composite Film) (1) Preparation of Propylene Polymer Composition A for Preparation of Layer a Component a was homopolypropylene with the trade name PPH-FA03 (available from Qingdao Refining & Chemical Co., Ltd., melt flow rate 3.1 g / 10 min, isotacticity 98%, molecular weight distribution Mw / Mn 4.7). Component b was polypropylene-g-styrene / maleic anhydride prepared above. Component c was polyolefin elastomer with the trade name 6102 (available from Exxon Corporation, ethylene-propylene copolymer). The various components prepared above were weighed and mixed according to the following proportions: 75 parts by weight of component a (Wa), 10 parts by weight of component b (Wb), and 15 parts by weight of component c (Wc). Next, a lubricant (PEG lubricant manufactured by Clariant, Switzerland, molecular weight 10,000, added at 0.1 parts by weight based on 100 parts by weight of the total mass of the above components a, b, and c) was added, and the mixture was then added to a high-speed mixer and mixed uniformly. The mixed material was then added to the feeder of a twin-screw extruder manufactured by W&P, and the material was fed into the twin screws, the screw temperature of which was maintained in the range of 160-230°C during processing. The material was melt-mixed uniformly by the screw, extruded, pelletized, and dried. Pellets of propylene polymer composition A were obtained, and after measurement, the pellets had a melt flow rate (MFR A = 2.9 g / 10 min.

[0470] (2) Preparation of Propylene Polymer Composition B for Preparation of Layer b Component x was a random polypropylene with the trade name F5006 (available from Yanshan Petrochemical Company, an ethylene-propylene-butene terpolymer with a melt flow rate of 5.2 g / 10 min). Component y was a polyolefin elastomer with the trade name 6102 (available from Exxon Corporation, an ethylene-propylene copolymer). The various components prepared above were weighed and mixed in a ratio of 75 parts by weight of component x (Wx) and 25 parts by weight of component y (Wy). The Wc:Wy ratio was 3:5. The other steps were the same as in step (1), and pellets of propylene polymer composition B were finally obtained. After measurement, the pellets had a melt flow rate MFR B = 3.2 g / 10 min.

[0471] (3) Preparation of composite films After drying the pellets of propylene polymer composition A and propylene polymer composition B obtained in steps (1) and (2) above, propylene polymer composition A was added to the core layer extruder of a multi-layer extrusion casting machine, propylene polymer composition B was added to the top layer extruder of the multi-layer extrusion casting machine, and an inorganic antiblocking agent (silica, as described above) was added to the top layer extruder, with the weight ratio of the antiblocking agent to the propylene polymer composition pellets being 0.2:100. During the casting process, the temperature of the casting quench roll was set to 30°C. After winding, a composite film consisting of a top layer (layer b) and a core layer (layer a) was prepared. The thickness of the composite film was 50 μm, and the thickness ratio of layer b to layer a was 1:2.

[0472] [Table 9]

[0473] As can be seen from the results in Table 9, adding polar monomer-modified polypropylene to the composite film of the present invention can achieve a higher surface energy. As a result, the resulting composite film has better adhesion to other materials. By adding grafted propylene polymer, a higher volume resistivity can be achieved, and therefore, the resulting composite film has better electrical insulation performance.

[0474] Although the present invention has been described with reference to the examples, the present invention is not limited to these examples and the scope of the present invention is not limited to these examples. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the present invention.

[0475] Furthermore, it should be noted that various specific technical features described in the above specific embodiments may be combined in any appropriate manner if there is no contradiction. Furthermore, various different embodiments of the present invention may be combined in any manner unless it is contrary to the spirit of the present invention, and such combinations shall also be considered as the disclosure of the present invention.

[0476] The endpoints of the ranges and any values ​​disclosed herein are not limited to the exact ranges or values ​​set forth above, but should be understood to include values ​​close to these ranges or values. Numerical ranges can be combined with each other between the endpoints of the various ranges, between the endpoints and the individual point values ​​of the various ranges, and between the individual point values ​​to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

Claims

1. A propylene polymer-based composite film comprising at least two different layers, a layer a and a layer b; Layer a and layer b each comprise at least one propylene polymer; At least one of layers a and b comprises a propylene impact copolymer; the propylene impact copolymer comprises an elastic portion that forms a dispersed rubber phase band in the composite film; The rubber phases are arranged parallel to each other, A composite film, wherein the average size of the transverse axis of the rubber phase is 20 to 200 nm and the average aspect ratio is 5 to 20, as measured by observing a cross section of the composite film cut along the transverse direction (TD) with an atomic force microscope.

2. The composite film according to claim 1, wherein the rubber phase has an average size of a transverse axis of 20 to 150 nm and an average aspect ratio of 5 to 15, as measured by observing a cross section of the composite film cut along the transverse direction with an atomic force microscope.

3. 3. The composite film according to claim 1, wherein the cross-sections of the rubber phases have an angle of 10 degrees or less with respect to each other, as measured by observing a cross-section of the composite film cut along the transverse direction with an atomic force microscope.

4. The composite film according to any one of claims 1 to 3, wherein the elastic portion appears as a spherical or nearly spherical rubber phase in a scanning electron micrograph of an impact test piece of the propylene impact copolymer.

5. the propylene impact copolymer is a propylene impact copolymer containing ethylene units, 5. The composite film according to claim 1, wherein the elastic portion is a copolymer portion containing an ethylene unit.

6. The composite film of claim 5, wherein the elastic portion is selected from the group consisting of an ethylene-propylene copolymer portion and an ethylene-butylene copolymer portion.

7. The propylene impact copolymer comprises a propylene homopolymer portion and the ethylene unit-containing copolymer portion; and / or The content of the ethylene unit-containing copolymerized portion in the propylene impact copolymer is 3 to 15 wt %; and / or the ethylene unit content of the propylene impact copolymer is 1 to 14 wt. %, based on the total weight of the propylene impact copolymer; and / or The propylene impact copolymer has a room-temperature xylene soluble content of ethylene units of 40% by weight or less; and / or The propylene impact copolymer has a room temperature xylene soluble matter having an ethylene unit sequence [EEE] content of 20% by weight or less as measured by 13 C NMR; and / or 6. The composite film according to claim 5, wherein the propylene impact copolymer has a melt flow rate of 1 to 10 g / 10 min under a load of 2.16 kg at 230°C.

8. Both layer a and layer b comprise the propylene impact copolymer, and the propylene impact copolymer of layer a and the propylene impact copolymer of layer b are the same or different; or 8. The composite film according to claim 1, wherein only one of the layers a and b contains the propylene impact copolymer.

9. 9. The composite film according to claim 1, wherein at least one of the layers a and b comprises a polyolefin elastomer.

10. The composite film of claim 9, wherein the polyolefin elastomer is an elastomeric copolymer of ethylene and an alpha olefin, the alpha olefin being a C 3 -C 12 alpha olefin.

11. The composite film of claim 10, wherein the α-olefin is at least one selected from the group consisting of propylene, 1-butene, 1-hexene, and 1-octene.

12. The composite film according to claim 9, wherein the polyolefin elastomer has a shear viscosity ratio η 160 / η 640 of 1.2 to 3 at 230°C under shear rates of 160 r -1 and 640 r -1 , and / or a shear viscosity η 640 of 100 to 500 Pa·s at 230°C under a shear rate of 640 r -1 , the shear viscosity being measured using a capillary rheometer in accordance with ISO 11443:2014.

13. the propylene impact copolymer and the elastic portion of the polyolefin elastomer form a dispersed rubber phase in the composite film; the rubber phase is in the form of a band; The average size of the horizontal axis of the rubber phase is 20 to 200 nm, The composite film according to any one of claims 9 to 12, wherein the average aspect ratio of the rubber phase is 5 to 20, as measured by observing a cross section of the composite film cut in the transverse direction with an atomic force microscope.

14. Both layer a and layer b comprise the polyolefin elastomer, and the polyolefin elastomer of layer a and the polyolefin elastomer of layer b are the same or different; or The composite film according to any one of claims 9 to 12, wherein only one of the layer a and the layer b contains the polyolefin elastomer.

15. The composite film of claim 14, wherein the ratio of the weight proportion of the polyolefin elastomer in layer a to the weight proportion of the polyolefin elastomer in layer b is 6:1 to 1:

6.

16. 16. Composite film according to any one of claims 1 to 15, characterized in that layer a comprises homopolypropylene and / or a propylene random copolymer.

17. The homopolypropylene has a melt flow rate of 2 to 15 g / 10 min under a load of 2.16 kg at 230°C; and / or 17. The composite film of claim 16, wherein the homopolypropylene has an isotacticity of greater than 97%; and / or the homopolypropylene has a molecular weight distribution Mw / Mn of 4.5 to 7.

0.

18. The propylene random copolymer is at least one selected from the group consisting of an ethylene-propylene-butene ternary random copolymer, a propylene-ethylene binary random copolymer, and a propylene-butene binary random copolymer; and / or The propylene random copolymer has a melt flow rate of 2 to 15 g / 10 min under a load of 2.16 kg at 230°C; and / or The composite film according to claim 16, wherein the propylene random copolymer has a molecular weight distribution Mw / Mn of 4.5 to 7.

0.

19. 19. A composite film according to any one of claims 1 to 18, characterized in that layer b comprises a propylene random copolymer.

20. The propylene random copolymer is at least one selected from the group consisting of an ethylene-propylene-butene ternary random copolymer, a propylene-ethylene binary random copolymer, and a propylene-butene binary random copolymer; and / or The propylene random copolymer has a melt flow rate of 2 to 15 g / 10 min under a load of 2.16 kg at 230°C; and / or 20. The composite film according to claim 19, wherein the propylene random copolymer has a molecular weight distribution Mw / Mn of 4.5 to 7.

0.

21. 21. The composite film according to claim 19 or 20, wherein layer a comprises the polyolefin elastomer, the propylene impact copolymer and other types of propylene polymers, the other types of propylene polymers being selected from the homopolypropylene and / or propylene random copolymer, and layer b comprises the random propylene copolymer and the polyolefin elastomer.

22. Layer a comprises, based on the total weight of layer a, 40 to 90 wt % of a propylene impact copolymer, 5 to 40 wt % of other types of propylene polymers, and 2 to 30 wt % of a polyolefin elastomer; and 22. The composite film according to claim 21, wherein layer b comprises 40 to 95 wt % of the propylene random copolymer and 5 to 60 wt % of the polyolefin elastomer, based on the total weight of layer b.

23. 21. The composite film according to claim 19 or 20, wherein layer a comprises the homopolypropylene, the propylene impact copolymer and the polyolefin elastomer, and layer b comprises the random propylene copolymer and the polyolefin elastomer.

24. The ratio of the weight proportion of the polyolefin elastomer in layer a to the weight proportion of the polyolefin elastomer in layer b is 2:1 to 1:4; and / or 24. The composite film according to claim 23, wherein layer a comprises, based on the total weight of layer a, 40 to 90 wt % of the homopropylene, 5 to 40 wt % of the propylene impact copolymer, and 2 to 30 wt % of the polyolefin elastomer; and layer b comprises, based on the total weight of layer b, 40 to 95 wt % of the random propylene copolymer and 5 to 60 wt % of the polyolefin elastomer.

25. 21. The composite film according to claim 19 or 20, characterized in that layer a comprises a propylene polymer and the polyolefin elastomer, the propylene polymer being selected from homopolypropylene and / or the propylene impact copolymer, and layer b comprises the random propylene copolymer, the polyolefin elastomer and the propylene impact copolymer.

26. The ratio of the weight proportion of the polyolefin elastomer in layer a to the weight proportion of the polyolefin elastomer in layer b is 6:1 to 1:4; and / or 26. The composite film of claim 25, wherein layer a comprises, based on the total weight of layer a, 50 to 95 wt % of the propylene polymer and 5 to 50 wt % of the polyolefin elastomer; and layer b comprises, based on the total weight of layer b, 40 to 90 wt % of the random propylene copolymer, 5 to 40 wt % of the polyolefin elastomer, and 2 to 30 wt % of the propylene impact copolymer.

27. The composite film according to any one of claims 1 to 26, wherein layer a and / or layer b further comprises at least one additive selected from the group consisting of antioxidants, lubricants, halogen absorbers, light stabilizers, heat stabilizers, colorants, fillers, slip agents, anti-blocking agents, surface adhesives, electromagnetic shielding agents, flame retardants, insulating additives, and antistatic agents.

28. the antioxidant is at least one selected from the group consisting of antioxidant 1076, antioxidant 1010, antioxidant 168, and a thioester antioxidant; and / or the lubricant is a PEG lubricant and / or a monoglyceride lubricant; and / or the filler is at least one conductive filler selected from the group consisting of carbon black, graphite, carbon nanotubes, carbon fibers, conductive metal particles, conductive metal fibers, conductive metal-coated fillers, and metal oxides; and / or the electromagnetic shielding agent is a conductive metal filler and / or a carbon material, the conductive metal filler being a conductive metal particle and / or a conductive metal fiber; the carbon material being one or more of carbon black, graphite, graphene, and carbon nanotubes; and / or The flame retardant is at least one selected from the group consisting of metal or non-metal hydroxides and / or oxide hydrates, phosphorus-based flame retardants, boron-based flame retardants, antimony-based flame retardants, and intumescent flame retardants; and / or the colorant is at least one selected from the group consisting of azo pigments, phthalocyanine pigments, heterocyclic pigments, lake pigments, dyes, optical brighteners, and fluorescent pigments; and / or 28. The composite film of claim 27, wherein the lubricant is selected from an amide-based lubricant, which is at least one of erucamide, oleamide, stearamide, behenamide, stearyl erucamide, and ethylene bisstearamide, or a mixture of an amide-based lubricant and a migration-resistant lubricant, which is at least one of polytetrafluoroethylene microparticles, polyimide microparticles, polyamide microparticles, polycarbonate microparticles, silicone, nano-calcium carbonate, mica, and nano-silica.

29. A composite film as described in claim 27, characterized in that the content of the antioxidant is 0.1 to 0.8 parts by weight based on 100 parts by weight of the total weight of the layer.

30. A composite film as described in claim 27, characterized in that the content of the lubricant is 0.01 to 0.5 parts by weight based on 100 parts by weight of the total weight of the layer.

31. A composite film as described in Claim 28, characterized in that the conductive filler is added to layer b, and the conductive filler is added in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the total weight of the matrix polymer of layer b.

32. A composite film as described in Claim 27, characterized in that the electromagnetic shielding agent is added to layer b in an amount of 5 to 30 parts by weight based on 100 parts by weight of the matrix polymer of layer b.

33. A composite film as described in Claim 27, characterized in that the electromagnetic shielding agent is used in combination with a titanate coupling agent.

34. The composite film described in claim 27, characterized in that a lubricant is added to both layer a and layer b, an amide-based lubricant is added to layer a, and a mixture of an amide-based lubricant and a migration-resistant lubricant is added to layer b.

35. 28. The composite film of claim 27, wherein the surface adhesive is a polar monomer modified polypropylene, the polar monomer being selected from the group consisting of hydroxyl group containing comonomers, cyano group containing comonomers, and anhydride monomers.

36. The composite film of claim 35, wherein the polar monomer is selected from the group consisting of hydroxy acids, vinyl alcohols, cyanoacrylates, maleic anhydride and itaconic anhydride.

37. A composite film as described in Claim 35, characterized in that the polar monomer-modified polypropylene is added to layer b in an amount of 1 to 30 weight % based on the total weight of layer b.

38. 28. The composite film of claim 27, wherein the insulating additive is a grafted propylene polymer.

39. A composite film as described in Claim 38, characterized in that the insulating additive is added to layer a and / or layer b in an amount of 5 to 45 weight % based on the total weight of the layers.

40. The composite film of claim 38, wherein the grafted propylene polymer comprises structural units derived from copolypropylene and structural units derived from the following grafted monomers: Combinations of acrylates, acrylic acid, styrene, alkenyl-containing silanes, alkenyl-containing heterocyclic monomers; and anhydrides having at least one olefinically unsaturated and alkenyl-containing polymerizable monomer.

41. the grafted propylene polymer is prepared from a copolypropylene and a grafting monomer via a solid-state grafting reaction; and / or In the copolypropylene, the comonomers other than propylene are ethylene and C ４ -C ８ at least one selected from the group consisting of α-olefins; and / or The copolypropylene has at least one of the following characteristics: a comonomer content of 0.5 to 30 mol %; a xylene soluble content of 2 to 80 wt %; a comonomer content in the soluble content of 10 to 70 wt %; an intrinsic viscosity ratio of the soluble content to the copolypropylene of 0.3 to 5; a melt flow rate at 230°C under a load of 2.16 kg of 0.01 to 60 g / 10 min; a melting temperature (Tm) of greater than 100°C; and a weight average molecular weight of 20 x 10 ４ ~60 x 10 ４ g / mol; and / or The composite film according to any one of claims 38 to 40, wherein the grafted propylene polymer has a melt flow rate of 0.01 to 30 g / 10 min under a load of 2.16 kg at 230°C.

42. The grafted propylene polymer comprises structural units derived from a copolypropylene and structural units derived from an acrylate monomer and optionally an acrylic acid monomer and grafted thereto; the content of the grafted structural units derived from an acrylate monomer and optionally an acrylic acid monomer is 0.3 to 7 wt % based on the weight of the grafted propylene polymer; the molar ratio of the structural units derived from the acrylate monomer to the structural units derived from the acrylic acid monomer in the grafted propylene polymer is 1:0 to 2; or The grafted propylene polymer comprises structural units derived from copolypropylene and structural units derived from styrene monomers; the content of the grafted structural units derived from styrene monomers in the grafted propylene polymer is 0.5 to 14 wt % based on the weight of the grafted propylene polymer; or The grafted propylene polymer comprises structural units derived from a copolypropylene and structural units derived from an alkenyl-containing silane monomer; the content of the grafted structural units derived from the alkenyl-containing silane monomer in the grafted propylene polymer b is 0.2 to 6 wt % based on the weight of the grafted propylene polymer; or the grafted propylene polymer comprises structural units derived from a copolypropylene, structural units derived from an anhydride monomer, and structural units derived from an alkenyl-containing polymerizable monomer, wherein the alkenyl-containing polymerizable monomer is at least one selected from the group consisting of vinyl acetate, styrene, α-methylstyrene, (meth)acrylate, vinyl alkyl ether, vinylpyrrolidone, vinylpyridine, vinylimidazole, and acrylonitrile; the anhydride is selected from maleic anhydride and / or itaconic anhydride; the content of grafted structural units derived from anhydride monomer and alkenyl-containing polymerizable monomer is 0.1 to 5 wt %; and / or the content of grafted structural units derived from anhydride monomer is 0.05 to 2 wt %; and / or the molar ratio of the structural units derived from anhydride monomer to the structural units derived from alkenyl-containing polymerizable monomer is 1:1 to 20; or The composite film according to any one of claims 38 to 41, wherein the grafted propylene polymer comprises structural units derived from a copolypropylene and structural units derived from an alkenyl-containing heterocyclic monomer; and the content of the grafted structural units derived from the alkenyl-containing heterocyclic monomer is 0.5 to 6 wt% based on the weight of the grafted propylene polymer.

43. The melt flow rate of the material of layer a at 230°C under a load of 2.16 kg is 2 to 10 g / 10 min; and / or 43. A composite film according to any one of claims 1 to 42, characterized in that the material of layer b has a melt flow rate of 2 to 10 g / 10 min at 230°C under a load of 2.16 kg.

44. 160 r at 230 °C －１ The difference in shear viscosity between the material of layer a and the material of layer b under a shear rate of ηA １６０ -ηb １６０ , and 640 r at 230 ° C. －１ The difference in shear viscosity between the material of layer a and the material of layer b under a shear rate of ηA ６４０ -ηb ６４０ , are both greater than or equal to 0, and two (ηA １６０ -ηb １６０ ) / (ηA ６４０ -ηb ６４０ 44. The composite film of claim 1, wherein the ratio of the shear viscosity of the polymer to the total polymer is 1 to 2.6, and the shear viscosity is measured using a capillary rheometer in accordance with ISO 11443:2014.

45. The composite film of any one of claims 1 to 44, characterized in that the composite film further comprises one or more additional layers, layer b being a surface layer of the composite film, the composition of the additional layer being the same as or different from the composition of layer a or layer b, and when the composite film is a three-layer film, the additional layer is referred to as layer c, and layer b and layer c are located on both sides of layer a, respectively.

46. 46. ​​The composite film according to claim 45, wherein the ratio of the total thickness of the layers other than layer a to the thickness of layer a is 1:6 to 2:

1.

47. The composite film according to any one of claims 1 to 46, characterized in that the composite film has one or more of the following properties: 1) Pendulum impact strength is 0.4 J or more; 2) the film haze is less than 7%; 3) The longitudinal tensile strength is 40 MPa or more; 4) Heat seal strength at 150°C is 12 N / 15 mm or more; 5) The thickness deviation in the MD direction is 1.3 or less; 6) The thickness deviation in the TD direction is 1.5 or less; 7) The deviation of impact resistance in the MD direction is 0.05 or less; 8) The deviation of impact resistance in the TD direction is less than 0.07; 9) Surface energy is 29 mN / m or more; 10) Volume resistivity is 1.5 x 10 １５ It is Ω·m or more.

48. A method for preparing a composite film according to any one of claims 1 to 47, comprising the steps of: The raw material compositions for forming the various layers are subjected to extrusion molding, optionally followed by a pelletizing step, to form the composite film; Before the extrusion step, the elastic portion of the propylene impact copolymer used in the raw material composition forms a granular rubber phase, and the average particle size of the granular rubber phase is 1.8 μm or less, and the maximum particle size of the granular rubber phase is 2.5 μm or less, as measured by observing the cross section of an impact test piece with a scanning electron microscope.

49. 49. The method of claim 48, wherein the elastic portion of the propylene impact copolymer used in the feedstock composition forms a spherical or nearly spherical rubber phase.

50. 50. The method of claim 48 or 49, further comprising the step of subjecting the resulting composite film to stretching.

51. The method of claim 50, wherein the composite film obtained is subjected to biaxial stretching.

52. Use of a composite film according to any one of claims 1 to 47 or obtainable by the method according to any one of claims 48 to 51 in the field of packaging materials.

53. A packaging material comprising a composite film according to any one of claims 1 to 47, or a composite film obtainable by the method according to any one of claims 48 to 51.

54. The packaging material described in claim 53, wherein the packaging material is a battery packaging material, an electronic product packaging material or a food packaging material.

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