A novel easily processable matt bottomless coating agent pre-coated base film and a preparation method thereof

Abstract

This invention discloses a novel easy-to-process matte pre-coated base film without primer and its preparation method, belonging to the field of biaxially oriented polypropylene technology. It sequentially comprises: a functional layer, a core layer, and a lower surface layer. The functional layer comprises the following raw materials in parts by weight: 3-5 parts organic anti-sticking agent, 10-15 parts polypropylene binary copolymer, and 80-87 parts linear low-density polyethylene. The core layer comprises the following raw materials in parts by weight: 1-2 parts antistatic agent masterbatch and 98-99 parts homopolymer polypropylene. The matte layer is made from a matte masterbatch, which is a binary blend of polypropylene and polyethylene. This invention improves the physical properties of the product and gives it better processability by replacing linear low-density polyethylene with a certain proportion of polypropylene binary copolymer.

Description

Technical Field

[0001] This invention belongs to the field of biaxially oriented polypropylene technology, specifically relating to a novel easy-to-process matte primerless pre-coated base film and its preparation method. Background Technology

[0002] Pre-coated films without a primer do not require corona treatment or primer coating; the pre-coated film is obtained by directly coating EVA onto the surface of the functional layer. This increases the pre-coating line speed, saves on primer and drying equipment required for pre-coated films, and makes downstream processing more environmentally friendly and lower in cost. Matte film, when laminated, can create a natural product image for food packaging. Laminating matte film with packaging paper can significantly enhance the packaging's quality, giving it the appearance of a paper product.

[0003] The functional layer of the primerless pre-coated base film uses linear low-density polyethylene (LLDPE), which has fewer branches, closer intermolecular distances, and a higher density, typically between 0.915 and 0.945 g / cm³. Due to these structural differences, LLDPE exhibits higher tear resistance and fatigue resistance, while also possessing superior transparency and surface smoothness compared to LLDPE. However, its melt index is 2.0-2.2 g / 10 min, significantly lower than that of homopolymer polypropylene (3.0-3.5 g / 10 min). This results in uneven edge stretching and poor thickness during biaxial stretching, leading to a finished product yield of only around 80%. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a novel easy-to-process matte primerless pre-coated base film and its preparation method, thereby solving the problems in the prior art.

[0005] The objective of this invention can be achieved through the following technical solutions: A novel easy-to-process matte primerless pre-coated base film comprises, in sequence: a functional layer, a core layer, and a lower surface layer; the functional layer comprises the following raw materials in parts by weight: 3-5 parts of organic anti-blocking agent, 10-15 parts of polypropylene binary copolymer, and 80-87 parts of linear low-density polyethylene. The core layer comprises the following raw materials in parts by weight: 1-2 parts of antistatic agent masterbatch and 98-99 parts of homopolymer polypropylene; The raw material for the matting layer is matting masterbatch, which is a binary blend of polypropylene and polyethylene.

[0006] Furthermore, the organic anti-adhesive is: organosilicon microspheres with polypropylene as a carrier.

[0007] Further, the polypropylene binary copolymer is a binary copolymer composed of polypropylene and low-density polyethylene, wherein the density of the low-density polyethylene is in the range of 0.91-0.93 g / cm³. 3 .

[0008] Furthermore, the melt index of the linear low-density polyethylene is 2.0-2.2 g / 10 min.

[0009] Furthermore, the antistatic agent masterbatch is: monoglyceride and ethoxyamine with polypropylene as the carrier.

[0010] Furthermore, the melt index of the homopolymer polypropylene is 3.0-3.5 g / 10 min.

[0011] Furthermore, the density range of polyethylene in the matte masterbatch is 0.94-0.96 g / cm³. 3 .

[0012] Furthermore, the thickness of the functional layer is 0.6-0.8 μm, the thickness of the core layer is 9-10 μm, and the thickness of the lower surface layer is 1.7-2.0 μm.

[0013] The above-mentioned method for preparing a novel easy-to-process matte primerless pre-coated base film includes the following steps: The raw materials for the core layer are mixed and added to the main extruder. The raw materials for the functional layer and the lower surface layer are added to two auxiliary extruders respectively. After heating and melting, extrusion and filtration, the functional layer melt, core layer melt and lower surface layer melt are obtained and then extruded in a three-layer die to form a film. The diaphragm is rapidly cooled to form a cast sheet, which is then dehydrated after cooling. The cast sheet is first preheated and then longitudinally stretched into a thick sheet; The thick sheet is first preheated, then stretched and shaped laterally.

[0014] The above-mentioned novel easy-to-process matte primer-free pre-coated base film is used in the production of product packaging.

[0015] The beneficial effects of this invention are: 1. The film of the present invention has a matting layer and a heat-sealing layer, thus possessing both matting and heat-sealing effects; 2. The haze of the film of the present invention can reach more than 75%, which has a good matting effect, and the matting effect is uniform and delicate, with a high haze. 3. The film of the present invention has excellent composite strength. Compared with ordinary matte film, it does not require corona treatment and primer treatment. Instead, a pre-coated film can be obtained by directly coating EVA on the upper surface of the functional layer. 4. The film of the present invention improves its processing performance. Compared with ordinary matte pre-coated base film without primer, it has better processability and the product yield can reach more than 94%. Detailed Implementation

[0016] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] A novel easy-to-process matte primerless pre-coated base film comprises, in sequence: a functional layer, a core layer, and a lower surface layer; the thickness of the functional layer is 0.6-0.8 μm, the thickness of the core layer is 9-10 μm, and the thickness of the lower surface layer is 1.7-2.0 μm.

[0018] The functional layer comprises the following raw materials in parts by weight: 3-5 parts organic anti-adhesive, 10-15 parts polypropylene binary copolymer, and 80-87 parts linear low-density polyethylene. The organic anti-adhesion agent is: silicone microspheres with polypropylene as the carrier; specifically, the manufacturer of the organic anti-adhesion agent is LyondellBasell, and the brand name is AB225LT; The polypropylene binary copolymer is a copolymer composed of polypropylene and low-density polyethylene, with the low-density polyethylene having a density range of 0.91-0.93 g / cm³. 3 Specifically, the manufacturer of the polypropylene binary copolymer is TPC, and the grade is FS5612.

[0019] The melt index of linear low-density polyethylene is 2.0-2.2 g / 10 min. Specifically, the manufacturer of linear low-density polyethylene is SK, and the grade is FT850.

[0020] The core layer comprises the following raw materials in parts by weight: 1-2 parts of antistatic agent masterbatch and 98-99 parts of homopolymer polypropylene; The antistatic agent masterbatch consists of monoglycerides and ethoxyamines with polypropylene as the carrier; specifically, the manufacturer of the antistatic agent masterbatch is LyondellBasell, and the brand name is SPA2556WOBDC. The melt index of homopolymer polypropylene is 3.0-3.5 g / 10 min.

[0021] The raw material for the matting layer is matting masterbatch, which is a binary blend of polypropylene and high-density polyethylene, wherein the density of the high-density polyethylene ranges from 0.94 to 0.96 g / cm³. 3 Specifically, the manufacturer of the matte masterbatch is Deguan, and the grade is D6612.

[0022] The preparation method of the above-mentioned novel easy-to-process matte primerless pre-coated base film includes the following steps: S1. After mixing the raw materials of the core layer, add them to the main extruder. Add the raw materials of the functional layer and the lower surface layer to two auxiliary extruders respectively. After heating and melting, extrusion and filtration, functional layer melt, core layer melt and lower surface layer melt are obtained. The above melts are combined and extruded in the three-layer structure die to form a film. S2. The diaphragm is attached to the cooling roller by compressed air and rapidly cooled to form a casting. Then, it is cooled by a water bath and the cooled casting is dehydrated by a rubber roller and compressed air. S3. The cast sheet is first preheated and then longitudinally stretched into a thick sheet; S4. The thick sheet is first preheated, then stretched laterally and shaped to obtain a film; S5. After the film is shaped and cooled, it enters the traction system to flatten, trim, measure thickness and corona treatment, and then is wound into a master roll; after aging treatment, it is slit and packaged to produce a new type of easy-to-process matte primer-free pre-coated base film.

[0023] In S1, the temperature during the confluence extrusion is 235-245℃; in S2, the temperature of the chiller roller is 30-35℃; in S3, the preheating temperature of the cast sheet is 120-130℃, the temperature during longitudinal stretching is 120-125℃, and the stretching ratio is 4.5-5 times; in S4, the preheating temperature of the thick sheet is 170-175℃, the temperature during transverse stretching is 150-155℃, and the setting temperature is 160-165℃.

[0024] The technical solution of the present invention will be described below through the following embodiments and comparative examples. The sources of each raw material in the embodiments and comparative examples are as follows: Organic anti-adhesion agent: The manufacturer of the organic anti-adhesion agent is LyondellBasell, and the brand name is AB225LT; Polypropylene binary copolymer: The manufacturer of the polypropylene binary copolymer is TPC, and the grade is FS5612; Linear low-density polyethylene: Manufacturer: SK, Grade: FT850; Antistatic agent masterbatch: LyondellBasell, grade SPA2556WOBDC; Homopolymer polypropylene: manufactured by Sinopec, grade HP550J; Matte masterbatch: Manufacturer: Deguan, Grade: D6612; Example 1 This embodiment provides a novel easy-to-process matte primer-free pre-coated base film. The film consists of a functional layer, a core layer, and a bottom surface layer. The thickness of the functional layer is 0.7 μm, the thickness of the core layer is 9.4 μm, and the thickness of the bottom surface layer is 1.9 μm.

[0025] The functional layer is a polyethylene layer, comprising the following parts by weight of raw materials: 5 parts of organic anti-adhesive, 10 parts of polypropylene binary copolymer, and 85 parts of linear low-density polyethylene; the core layer is a homopolymer polypropylene layer, comprising the following parts by weight of raw materials: 1 part of antistatic agent masterbatch and 99 parts of homopolymer polypropylene; the lower surface layer is a matte layer, and the raw material is matte masterbatch.

[0026] The preparation method of the above-mentioned novel easy-to-process matte primerless pre-coated base film includes the following steps: After mixing the raw materials of each component of the core layer, they are added to the main extruder. The raw materials of each component of the functional layer and the lower surface layer are added to two auxiliary extruders respectively. After heating, melting, extrusion and filtration, functional layer melt, core layer melt and lower surface layer melt are obtained. The above melts are combined and extruded in a three-layer structure die to form a film. The temperature during the combined extrusion is 245℃. S2. The diaphragm is attached to the cooling roller by compressed air and rapidly cooled to form a casting. Then, it is cooled by a water bath. The cooled casting is then dehydrated by a rubber roller and compressed air. The temperature of the cooling roller is 35℃. S3. The cast sheet is first preheated and then longitudinally stretched into a thick sheet. The preheating temperature of the cast sheet is 130℃, the longitudinal stretching temperature is 125℃, and the stretching ratio is 4.5 times. S4. The thick sheet is first preheated, then stretched laterally and shaped to obtain a film. The preheating temperature of the thick sheet is 175℃, the temperature during lateral stretching is 153℃, and the shaping temperature is 163℃. S5. After the film is shaped and cooled, it enters the traction system to flatten, trim, measure thickness and corona treatment, and then is wound into a master roll; after aging treatment, it is slit and packaged to produce a new type of easy-to-process matte primer-free pre-coated base film.

[0027] Example 2 This invention proposes a novel easy-to-process matte pre-coated base film without primer. The film consists of a functional layer, a core layer, and a bottom surface layer. The thickness of the functional layer is 0.7 μm, the thickness of the core layer is 9.4 μm, and the thickness of the bottom surface layer is 1.9 μm.

[0028] The functional layer is a polyethylene layer, comprising the following parts by weight of raw materials: 5 parts of organic anti-adhesive, 25 parts of polypropylene binary copolymer, and 70 parts of linear low-density polyethylene; the core layer is a homopolymer polypropylene layer, comprising the following parts by weight of raw materials: 1 part of antistatic agent masterbatch and 99 parts of homopolymer polypropylene; the lower surface layer is a matte layer, and the raw material is matte masterbatch.

[0029] The preparation method of the above-mentioned novel easy-to-process matte primerless pre-coated base film includes the following steps: After mixing the raw materials of each component of the core layer, they are added to the main extruder. The raw materials of each component of the functional layer and the lower surface layer are added to two auxiliary extruders respectively. After heating, melting, extrusion and filtration, functional layer melt, core layer melt and lower surface layer melt are obtained. The above melts are combined and extruded in a three-layer structure die to form a film. The temperature during the combined extrusion is 245℃. S2. The diaphragm is attached to the cooling roller by compressed air and rapidly cooled to form a casting. Then, it is cooled by a water bath. The cooled casting is then dehydrated by a rubber roller and compressed air. The temperature of the cooling roller is 35℃. S3. The cast sheet is first preheated and then longitudinally stretched into a thick sheet. The preheating temperature of the cast sheet is 130℃, the longitudinal stretching temperature is 125℃, and the stretching ratio is 4.5 times. S4. The thick sheet is first preheated, then stretched laterally and shaped to obtain a film. The preheating temperature of the thick sheet is 175℃, the temperature during lateral stretching is 153℃, and the shaping temperature is 163℃. S5. After the film is shaped and cooled, it enters the traction system for flattening, edge trimming, thickness measurement, and corona treatment, and then is wound into a master roll; after aging treatment, it is slit and packaged to produce a new type of easy-to-process matte primer-free pre-coated base film. Comparative Example 1 A matte, primerless pre-coated base film consists of a functional layer, a core layer, and a lower surface layer. The thickness of the functional layer is 0.7 μm, the thickness of the core layer is 9.4 μm, and the thickness of the lower surface layer is 1.9 μm.

[0030] The functional layer is a polyethylene layer, comprising the following parts by weight of raw materials: 5 parts of organic anti-sticking agent and 95 parts of linear low-density polyethylene; the core layer is a homopolymer polypropylene layer, comprising the following parts by weight of raw materials: 1 part of antistatic agent masterbatch and 99 parts of homopolymer polypropylene; the lower surface layer is a matte layer, and the raw material is matte masterbatch.

[0031] The above-mentioned method for preparing a matte, primerless pre-coated base film includes the following steps: After mixing the raw materials of each component of the core layer, they are added to the main extruder. The raw materials of each component of the functional layer and the lower surface layer are added to two auxiliary extruders respectively. After heating, melting, extrusion and filtration, functional layer melt, core layer melt and lower surface layer melt are obtained. The above melts are combined and extruded in a three-layer structure die to form a film. The temperature during the combined extrusion is 245℃. S2. The diaphragm is attached to the cooling roller by compressed air and rapidly cooled to form a casting. Then, it is cooled by a water bath. The cooled casting is then dehydrated by a rubber roller and compressed air. The temperature of the cooling roller is 35℃. S3. The cast sheet is first preheated and then longitudinally stretched into a thick sheet. The preheating temperature of the cast sheet is 130℃, the longitudinal stretching temperature is 125℃, and the stretching ratio is 4.5 times. S4. The thick sheet is first preheated, then stretched laterally and shaped to obtain a film. The preheating temperature of the thick sheet is 175℃, the temperature during lateral stretching is 153℃, and the shaping temperature is 163℃. S5. After the film is shaped and cooled, it enters the traction system to flatten, trim, measure thickness and corona treatment, and then is wound into a master roll; after aging treatment, it is slit and packaged to produce a new type of easy-to-process matte primer-free pre-coated base film.

[0032] Experimental Test To verify the effectiveness of the present invention, haze and peel strength tests were conducted on the films produced in the two embodiments and a comparative example described above. The test standards were GB / T2410 and GB / T2790, respectively. The results are shown in the table below: Table 1. Performance test results of the thin films prepared in the examples and comparative examples. Based on the experimental results in Table 1, the following analysis is made: 1) By comparing Examples 1-2, it can be seen that when the amount of polypropylene binary copolymer added to the functional layer exceeds a certain proportion, the corresponding peel strength will decrease.

[0033] 2) By comparing the experimental results of Examples 1-2 and Comparative Example 1, it can be seen that the novel easy-to-process matte primerless pre-coated base film of the present invention can improve its processability better than that of ordinary matte primerless pre-coated base film without affecting its peel strength and haze.

[0034] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0035] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A novel easy-to-process matte primerless pre-coated base film, comprising, in sequence: Functional layer, core layer and lower surface layer; characterized in that: The functional layer comprises the following raw materials in parts by weight: 3-5 parts organic anti-adhesive, 10-15 parts polypropylene binary copolymer, and 80-87 parts linear low-density polyethylene. The core layer comprises the following raw materials in parts by weight: 1-2 parts of antistatic agent masterbatch and 98-99 parts of homopolymer polypropylene; The raw material for the matting layer is matting masterbatch, which is a binary blend of polypropylene and polyethylene.

2. The novel easy-to-process matte primerless pre-coated base film according to claim 1, characterized in that, The organic anti-adhesion agent is: organosilicon microspheres with polypropylene as the carrier.

3. The novel easy-to-process matte primerless pre-coated base film according to claim 1, characterized in that, The polypropylene binary copolymer is a binary copolymer composed of polypropylene and low-density polyethylene, wherein the density of the low-density polyethylene is in the range of 0.91-0.93 g / cm³. 3 .

4. The novel easy-to-process matte primerless pre-coated base film according to claim 1, characterized in that, The linear low-density polyethylene has a melt index of 2.0-2.2 g / 10 min.

5. The novel easy-to-process matte primerless pre-coated base film according to claim 1, characterized in that, The antistatic agent masterbatch consists of monoglycerides and ethoxyamines with polypropylene as the carrier.

6. The novel easy-to-process matte primerless pre-coated base film according to claim 1, characterized in that, The melt index of the homopolymer polypropylene is 3.0-3.5 g / 10 min.

7. The novel easy-to-process matte primerless pre-coated base film according to claim 1, characterized in that, The density range of polyethylene in the matting masterbatch is 0.94-0.96 g / cm³. 3 .

8. The novel easy-to-process matte primerless pre-coated base film according to claim 1, characterized in that, The thickness of the functional layer is 0.6-0.8 μm, the thickness of the core layer is 9-10 μm, and the thickness of the lower surface layer is 1.7-2.0 μm.

9. The method for preparing the novel easy-to-process matte primerless pre-coated base film according to any one of claims 1-8, characterized in that, Includes the following steps: The raw materials for the core layer are mixed and added to the main extruder. The raw materials for the functional layer and the lower surface layer are added to two auxiliary extruders respectively. After heating and melting, extrusion and filtration, the functional layer melt, core layer melt and lower surface layer melt are obtained and then extruded in a three-layer die to form a film. The diaphragm is rapidly cooled to form a cast sheet, which is then dehydrated after cooling. The cast sheet is first preheated and then longitudinally stretched into a thick sheet; The thick sheet is first preheated, then stretched and shaped laterally.

10. The application of the novel easy-processing matte primerless pre-coated base film according to any one of claims 1-8 in the manufacture of product packaging.

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