High-barrier membrane as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of functional membranes, and discloses a high-barrier membrane as well as a preparation method and application thereof. The high-barrier membrane comprises a first outer layer, a middle layer and a second outer layer which are sequentially arranged, wherein the first outer layer and the second outer layer comprise polypropylene, an initiator, an antioxidant, an ultraviolet light absorber and a light stabilizer; the intermediate layer contains a cycloolefin polymer, maleic anhydride, an antioxidant, an ultraviolet light absorber, and a light stabilizer. According to the diaphragm, an interlayer physical anchoring structure is formed through a co-extrusion process in combination with cooling calendering roller control, and the technical problems that in the prior art, interlayer combination is weak, and barrier property and mechanical property are contradictory are solved. The water vapor permeability of the high-barrier membrane is smaller than or equal to 0.1 g / (m.24h), the oxygen permeability is smaller than or equal to 0.1 cm / (m.24h. Atm), the tensile strength is larger than or equal to 30 MPa, the yellowing index delta b is smaller than or equal to 0.4, solvent resistance is excellent, and the high-barrier membrane is suitable for the field of medicine and food packaging.

Description

Technical Field

[0001] The present invention relates to the technical field of functional diaphragms, and particularly to a high-barrier diaphragm and its preparation method and application. Background Art

[0002] In pharmaceutical packaging materials, high molecular plastics have become an important choice due to their excellent processing plasticity, damage resistance, and sealing and leakage resistance. High molecular polymers such as PVC, PE, PP, and PET are widely used in the production of pharmaceutical containers, and composite technologies are used to improve the barrier performance to meet the safety requirements of pharmaceutical products.

[0003] The existing PVC materials have disadvantages such as poor weather resistance, poor stability to light, heat, and oxygen, and may release harmful substances (such as vinyl chloride monomers) during long-term use, which have a negative impact on human health and drug effects. In addition, although cyclic olefin polymer materials have become an ideal choice due to their excellent water vapor barrier properties, chemical resistance, transparency, and biocompatibility, their high cost limits their wide application. Moreover, when reducing the thickness of the cyclic olefin polymer film to reduce costs, the mechanical properties of the material decline.

[0004] In this application, through a multi-layer composite technology, a composite material of cyclic olefin polymer and PP is used, and the bonding performance problem between the cyclic olefin polymer and the PP layer is solved through a hot melt composite technology. At the same time, high-barrier materials such as EVOH and PVOH are introduced in the coating design to achieve excellent water vapor and gas barrier properties, reduce the release of harmful substances, and avoid pollution to human health and drugs. Through the optimization of the multi-layer composite structure, the purpose of improving the rigidity of the film material and reducing costs is achieved, and the comprehensive performance of the pharmaceutical packaging material is further improved. Summary of the Invention

[0005] The present invention provides a high-barrier diaphragm and its preparation method and application to solve the technical problems of weak interlayer bonding, the contradiction between barrier properties and mechanical properties, poor weather resistance, and complex processes in the prior art.

[0006] On the one hand, the present invention provides a high-barrier diaphragm, which includes a first outer layer, an intermediate layer, and a second outer layer arranged in sequence from top to bottom; By weight, the first outer layer and the second outer layer independently include the following components: 100 - 1000 parts of polypropylene; 0.1 - 10 parts of initiator; 1 - 20 parts of antioxidant; 1 - 20 parts of ultraviolet absorber; 1 - 20 parts of light stabilizer; By weight, the intermediate layer includes the following components: 100 - 1000 parts of cycloolefin polymer; 0.5 - 15 parts of maleic anhydride; 1 - 20 parts of antioxidant; 1 - 20 parts of ultraviolet absorber; 1 - 20 parts of light stabilizer; The thicknesses of the first outer layer and the second outer layer are independently 5 - 250 μm.

[0007] A high-barrier film sheet provided by the present invention, wherein the polypropylene is isotactic or syndiotactic polypropylene, and the melt index is 1.9 - 19 g / 10 min.

[0008] A high-barrier film sheet provided by the present invention, wherein the cycloolefin polymer is an amorphous transparent polymer copolymerized from cyclic olefin monomers and linear olefin monomers, and the melt index is 1.8 - 50 g / 10 min.

[0009] A high-barrier film sheet provided by the present invention, wherein the total thickness of the high-barrier film sheet is 20 - 1000 μm, and the thickness of the intermediate layer is 10 - 600 μm.

[0010] A high-barrier film sheet provided by the present invention, wherein the initiator is one or more of dicumyl peroxide and benzoyl peroxide.

[0011] A high-barrier film sheet provided by the present invention, wherein the addition amount of maleic anhydride is 0.1% - 1.5% of the weight of the cycloolefin polymer.

[0012] On the other hand, the present invention provides a method for preparing a high-barrier film sheet, comprising the following steps: (1) Adopting a co-extrusion process in the order of the first outer layer, the intermediate layer, and the second outer layer, and cooling and shaping the co-extruded melt to obtain a sandwich-structured film layer; (2) Controlling the crystallinity through a cooling calender roll, the cooling and shaping temperature is 30 - 140 °C, and the surface roughness of the calender roll is 1.3 - 93.3 μm.

[0013] According to the method for preparing a high-barrier film sheet provided by the present invention, in step (1), the melt extrusion temperatures of the first outer layer and the second outer layer are 220 - 260 °C, and the melt extrusion temperature of the intermediate layer is 200 - 250 °C.

[0014] According to the method for preparing a high-barrier film sheet provided by the present invention, in step (2), the distance between the co-extrusion die head and the cooling calender roll is 1 - 50 cm.

[0015] On the other hand, the present invention provides an application of a high-barrier film sheet for the preparation of a drug packaging film or a food packaging film, and the water vapor transmission rate of the packaging film ≤ 0.1 g / (m 2·24 h), oxygen transmission rate ≤ 0.1 cm 3 / (m 2 ·24 h·atm).

[0016] Compared with the prior art, a high-barrier film sheet provided by the present invention, its preparation method and application have the following advantages: (1) For a high-barrier film sheet provided by the present invention, its preparation method and application, through a three-layer co-extrusion process (PP / COC / PP) combined with the roughness control and temperature gradient of a cooling calender roll, a physical anchoring structure is formed between layers, solving the problems of poor interlayer adhesion and easy peeling of the existing composite film, significantly improving the interlayer bonding strength, and ensuring the structural stability of the material in a complex environment.

[0017] (2) For a high-barrier film sheet provided by the present invention, its preparation method and application, by optimizing the thickness ratio of the outer layer of polypropylene to the middle layer of cycloolefin polymer, the contradiction between the decrease in mechanical properties after thinning of the cycloolefin polymer material and the requirement of high barrier performance is solved, achieving a water vapor transmission rate ≤ 0.1 g / (m 2 ·24 h), oxygen transmission rate ≤ 0.1 cm 3 / (m 2 ·24 h·atm) of high barrier performance, while maintaining excellent mechanical properties with a tensile strength ≥ 30 MPa.

[0018] (3) For a high-barrier film sheet provided by the present invention, its preparation method and application, by adding antioxidants, ultraviolet absorbers and light stabilizers, combined with the inherent chemical resistance of the cycloolefin polymer, the problems of easy degradation, release of harmful substances and insufficient solvent resistance of traditional materials in the environment of light, heat and oxygen are solved, so that the yellowing index Δb ≤ 0.4 after 168 hours of xenon lamp aging of the film sheet, and through water, ethanol and methyl ethyl ketone resistance tests, the weather resistance and chemical stability of the high-barrier film sheet are significantly improved.

[0019] (4) For a high-barrier film sheet provided by the present invention, its preparation method and application, through a one-step co-extrusion molding process and the control of the distance between the die head and the calender roll, the complex process of the traditional multi-layer composite film that requires additional coating or bonding layers is simplified, the problems of cumbersome process and high cost are solved, the production cost is reduced, and at the same time, the use of harmful adhesives is avoided, meeting the environmental protection requirements.

[0020] (5) For a high-barrier film sheet provided by the present invention, its preparation method and application, through the introduction of maleic anhydride and the optimization of initiators, the interfacial compatibility between the middle layer of cycloolefin polymer and the outer layer of polypropylene is enhanced, the problem of insufficient interlayer bonding performance between polypropylene and cycloolefin polymer in the prior art is solved, and the overall performance and service life of the composite film sheet are further improved. Description of the Drawings

[0021] To more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0022] Figure 1 It is a schematic process flow diagram of the preparation method of the high-barrier film provided by the embodiment of the present invention; Figure 2 It is a schematic structural diagram of the high-barrier film provided by the embodiment of the present invention; Figure 3 It is a thermodynamic curve diagram of the high-barrier film provided by the embodiment of the present invention; Figure 4 It is a microscopic schematic diagram of the anchoring effect of the high-barrier film provided by the embodiment of the present invention; Figure 5 It is an SEM image of the high-barrier film provided by the embodiment of the present invention.

[0023] Reference numerals: 1 - coextrusion die head; 2a, 2b, 2c, 2d - sizing rollers; 3 - cold air zone; A - functional layer; B - first outer layer; C - intermediate layer; D - second outer layer; E - adhesive layer. Detailed implementation manners

[0024] To make the objectives, technical solutions, and advantages of the present invention clearer, the following will clearly and completely describe the technical solutions in the present invention in conjunction with the drawings in the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0025] The present invention provides a high-barrier film, which includes a first outer layer, an intermediate layer, and a second outer layer arranged in sequence from top to bottom; By weight, the first outer layer and the second outer layer independently include the following components: 100 - 1000 parts of polypropylene, 0.1 - 10 parts of initiator, 1 - 20 parts of antioxidant, 1 - 20 parts of ultraviolet absorber, 1 - 20 parts of light stabilizer, preferably 300 - 800 parts of polypropylene, 0.5 - 5 parts of initiator, 5 - 15 parts of antioxidant, 5 - 15 parts of ultraviolet absorber, 5 - 15 parts of light stabilizer respectively, and further preferably 400 - 600 parts of polypropylene, 1 - 3 parts of initiator, 8 - 12 parts of antioxidant, 8 - 12 parts of ultraviolet absorber, 8 - 12 parts of light stabilizer respectively; By weight parts, the intermediate layer comprises the following components: 100 - 1000 parts of cycloolefin polymer, 0.5 - 15 parts of maleic anhydride, 1 - 20 parts of antioxidant, 1 - 20 parts of ultraviolet absorber, 1 - 20 parts of light stabilizer, preferably 300 - 800 parts of cycloolefin polymer, 2 - 10 parts of maleic anhydride, 5 - 15 parts of antioxidant, 5 - 15 parts of ultraviolet absorber, 5 - 15 parts of light stabilizer respectively, and further preferably 400 - 600 parts of cycloolefin polymer, 3 - 7 parts of maleic anhydride, 8 - 12 parts of antioxidant, 8 - 12 parts of ultraviolet absorber, 8 - 12 parts of light stabilizer respectively; The thicknesses of the first outer layer and the second outer layer are independently 5 - 250 μm, preferably 20 - 150 μm, and further preferably 50 - 100 μm.

[0026] In the present invention, the polypropylene is isotactic or syndiotactic polypropylene, and the melt index is 1.9 - 19 g / 10 min, preferably 3 - 15 g / 10 min, and further preferably 5 - 10 g / 10 min; wherein, the test conditions for the melt index are 230 °C / 2.16 kg.

[0027] In the present invention, the cycloolefin polymer is an amorphous transparent polymer copolymerized from cyclic olefin monomers and linear olefin monomers, and the melt index is 1.8 - 50 g / 10 min, preferably 5 - 30 g / 10 min, and further preferably 10 - 20 g / 10 min; wherein, the test conditions for the melt index are 260 °C / 2.16 kg.

[0028] In the present invention, the total thickness of the high - barrier film sheet is 20 - 1000 μm, preferably 100 - 800 μm, and further preferably 200 - 500 μm; the thickness of the intermediate layer is 10 - 600 μm, preferably 50 - 400 μm, and further preferably 100 - 300 μm.

[0029] In the present invention, the initiator is one or several of dicumyl peroxide and benzoyl peroxide, preferably dicumyl peroxide or benzoyl peroxide, and further preferably dicumyl peroxide.

[0030] In the present invention, the addition amount of maleic anhydride is 0.1% - 1.5% of the weight of the cycloolefin polymer, preferably 0.3% - 1%, and further preferably 0.5% - 0.8%.

[0031] The present invention also provides a preparation method of a high - barrier film sheet, comprising the following steps: (1) Adopt a co - extrusion process in the order of the first outer layer, the intermediate layer, and the second outer layer, and the co - extruded melt is cooled and shaped to obtain a sandwich - structured film layer; (2) Controlling the crystallinity by cooling the calender roll, the cooling and shaping temperature is 30 - 140 °C, preferably 50 - 120 °C, more preferably 80 - 100 °C; the surface roughness of the calender roll is 1.3 - 93.3 μm, preferably 10 - 50 μm, more preferably 20 - 40 μm.

[0032] In the present invention, in step (1), the melting and extrusion temperature of the first outer layer and the second outer layer is 220 - 260 °C, preferably 230 - 250 °C, more preferably 240 - 250 °C; the melting and extrusion temperature of the intermediate layer is 200 - 250 °C, preferably 210 - 240 °C, more preferably 220 - 235 °C.

[0033] In the present invention, in step (2), the distance between the co - extrusion die head and the cooling calender roll is 1 - 50 cm, preferably 10 - 30 cm, more preferably 15 - 25 cm.

[0034] The present invention also provides an application of the high - barrier film sheet, which is used for the preparation of drug packaging films or food packaging films. The water vapor transmission rate of the packaging film is ≤ 0.1 g / (m 2 ·24 h), and the oxygen transmission rate is ≤ 0.1 cm 3 / (m 2 ·24 h·atm).

[0035] The following combines Figures 1-5 to describe a high - barrier film sheet of the present invention, its preparation method and application.

[0036] Unless otherwise specified, all raw materials of the present invention can be purchased commercially or prepared according to conventional methods in the art.

[0037] In the examples of the present invention, the experimental materials used, unless otherwise specified, polypropylene is purchased from ExxonMobil Corporation, Borealis AG and Sun - Allomer Corporation, cycloolefin polymers are purchased from Topas Advanced Polymers GmbH and APEL Co., Ltd., antioxidants, light stabilizers and ultraviolet absorbers are purchased from BASF SE.

[0038] The multi - layer co - extrusion production line equipment uses the Extrusionline BREYER OptiFlex production line provided by BREYER GmbH Maschinenfabrik, Germany.

[0039] Among them, the preparation method of the high - barrier film sheet includes: An extruder having a screw with a diameter (D) of 60 mm and a length of 33D; a melt pump; a crosshead; a flat sheet die with a width of 450 mm; a three-roll calender with a horizontal roll arrangement, the third roll rotating approximately 45° relative to the horizontal position; a roller conveyor; a thickness gauge; a device for applying a protective film on both sides; a device for applying a protective film on both sides; a take-out device; a winding machine.

[0040] In an embodiment of the present invention, the performance test is carried out according to the following method: The multi-layer structure is observed by a scanning electron microscope (Hitachi S-4800, Japan); The water absorption rate is measured according to ASTM D570; The water vapor permeability is measured according to ASTM E96 Standard Test Methods for Water Vapor Transmission of Materials; The test conditions for oxygen permeability are GB / T 1038-2000: 23°C, 100% relative humidity; The tensile strength is measured according to ASTM D882; The weather resistance test is carried out using a xenon lamp weather resistance test chamber (JW-1101, Juwei Instruments / Hengduo Instruments Co., Ltd.), and the test conditions are: radiation intensity 0.68 W / m 2 , temperature 60°C, time 168 hours; The yellowness is measured according to ASTM D1003 standard, using an UltraScan Pro from Hunterlab, USA. The yellowness change index is calculated by the following formula: Δb=(b t -b0) / b0 where, b t is the yellowness index measured at 168 hours, and b0 is the yellowness index measured at the initial 0 hour; The solvent resistance is tested by dipping a lint-free cloth or paper towel in a solvent (water, ethanol, methyl isobutyl ketone) and wiping the coated film 50 times, and observing whether the coating is damaged. Pass if there is no damage, and fail if there is damage. Only the A layer is tested in the present invention.

[0041] Figure 1 is a schematic process flow diagram of the preparation method of the high-barrier film provided by the embodiment of the present invention.

[0042] As Figure 1As shown in the figure, the process flow of the preparation method of the high-barrier film provided by the embodiment of the present invention is as follows: on the Extrusion line BREYER OptiFlex production line, the polyester chip material is transported to the feed hopper of the extruder through a dryer, and the polyester chip material is heated and melted in the plasticizing device composed of the cylinder / screw of the extruder and then transported to the co-extrusion die head 1. The melt extruded from the die head reaches the calender, and the film is shaped and temperature-controlled and cooled on the guide rollers. In order to induce and control the crystallinity and stress release of the film, two pairs of cooling rollers with gradually decreasing surface temperatures are used. Among them, the cooling and shaping rollers 2a and 2b have higher temperatures, and the shaping rollers 2c and 2d have lower temperatures. The main function is to control the crystallinity during the gradual cooling process of the polymer film. After cooling in the cold air area 3, a high-barrier film is obtained.

[0043] Figure 2 is a schematic structural diagram of the high-barrier film provided by the embodiment of the present invention.

[0044] As Figure 2 shown, the high-barrier film provided by the embodiment of the present invention has a first outer layer A, an intermediate layer B, and a second outer layer C arranged in sequence from top to bottom.

[0045] Figure 3 is a thermodynamic curve diagram of the high-barrier film provided by the embodiment of the present invention.

[0046] As Figure 3 shown, in the first heating of the high-barrier film provided by the embodiment of the present invention, the crystallization peak appears at 124.9 °C. After eliminating the thermal history in the first cooling, the glass transition temperature of the material is shown as 74.2 °C in the second heating. It can be seen from this that this material has a relatively wide service temperature range.

[0047] Figure 4 is a microscopic schematic diagram of the anchoring effect of the high-barrier film provided by the embodiment of the present invention; Figure 5 is an SEM image of the high-barrier film provided by the embodiment of the present invention.

[0048] As Figure 4 and Figure 5 shown, in the high-barrier film provided by the embodiment of the present invention, an anchoring structure is formed between layers.

[0049] Example 1 Weigh the raw materials required for the first outer layer and the second outer layer according to the weight parts of 100 parts of polypropylene (DM55pharm), 1 part of antioxidant (Irganox MD 1024), 1 part of ultraviolet absorber (Irganox 245-DW), and 1 part of light stabilizer (Tinuvin 292), and mix them evenly; weigh the raw materials required for the middle layer according to the weight parts of 100 parts of cycloolefin polymer (TOPAS@COC 8007), 1 part of antioxidant (Irganox 1010), 1 part of ultraviolet absorber (Tinuvin 326), and 1 part of light stabilizer (Tinuvin 249), and mix them evenly; On the Extrusion line BREYER OptiFlex production line, convey the polyester chip material to the feed hopper of the extruder through a dryer, heat and melt the polyester chip material in the plasticizing device composed of the cylinder / screw of the extruder and convey it to the co-extrusion die head. Set the melting temperature of the first outer layer at 220 °C, the melting temperature of the middle layer at 200 °C, and the melting temperature of the second outer layer at 220 °C. The extrusion gap of the first outer layer and the second outer layer is 5 μm, the processing and melting extrusion gap of the middle layer is 10 μm, the distance from the co-extrusion die head to the calender roll is 1 cm, and the roughness of the calender roll is 1.3 - 93.3 μm. The melt extruded from the die head reaches the calender, and the film is shaped and temperature-controlled and cooled on the guide rolls. Among them, the temperature of 2a is 100 °C, the temperature of 2b is 100 °C, the temperature of 2c is 80 °C, and the temperature of 2d is 80 °C. After air cooling at 30 °C in the air cooling zone c, a high-barrier film sheet is obtained.

[0050] After testing, the water vapor transmission rate of the high-barrier film sheet provided in this example is 0.05 g / (m 2 ·24 h), the oxygen transmission rate is 0.03 cm 3 / (m 2 ·24 h·atm), the tensile strength is 35 MPa, and the yellowing index Δb is 0.1. It can be seen that the high-barrier film sheet provided in this example has a balance between barrier properties and mechanical properties, excellent weather resistance, and it can also be seen from the SEM image that the high-barrier film sheet provided in this example has a significant interlayer anchoring structure.

[0051] Example 2 Weigh the raw materials required for the first outer layer and the second outer layer in parts by weight of 1000 parts of polypropylene (Bormed RD808CF), 15 parts of antioxidant (Irganox 168), 15 parts of ultraviolet absorber (Tinuvin 479), and 15 parts of light stabilizer (Tinuvin 249), and mix them evenly; weigh the raw materials required for the intermediate layer in parts by weight of 1000 parts of cycloolefin polymer (TOPAS@COC 6017), 15 parts of antioxidant (Irgafos 126 (ED)), 15 parts of ultraviolet absorber (Tinuvin 928), and 15 parts of light stabilizer (Tinuvin 249), and mix them evenly; On the Extrusion line BREYER OptiFlex production line, convey the polyester chip material through a dryer to the feed hopper of the extruder, heat and melt the polyester chip material in the plasticizing device composed of the cylinder / screw of the extruder, and convey it to the co-extrusion die head. Set the melting temperature of the first outer layer at 260 °C, the melting temperature of the intermediate layer at 250 °C, the melting temperature of the second outer layer at 260 °C, the extrusion gap of the first outer layer and the second outer layer at 50 μm, the processing and melting extrusion gap of the intermediate layer at 200 μm, the distance from the co-extrusion die head to the calender roll at 50 cm, and the roughness of the calender roll at 1.3 - 93.3 μm. The melt extruded from the die head reaches the calender, and the film is shaped and temperature-controlled and cooled on the guide rollers. Among them, the temperature of 2a is 110 °C, the temperature of 2b is 110 °C, the temperature of 2c is 80 °C, and the temperature of 2d is 80 °C. After air cooling at 30 °C in the air-cooling zone c, a high-barrier film sheet is obtained.

[0052] After testing, the water vapor transmission rate of the high-barrier film sheet provided in this example is 0.03 g / (m 2 ·24 h), the oxygen transmission rate is 0.02 cm 3 / (m 2 ·24 h·atm), the tensile strength is 40 MPa, and the yellowness index Δb is 0.3. It can be seen that the high-barrier film sheet provided in this example still maintains high barrier properties and mechanical strength under high-temperature processes and is suitable for harsh environments.

[0053] Comparative Example 1 A film sheet provided in this comparative example is different from that in Example 1 in that there is no first outer layer (layer A), and the others are the same as those in Example 1.

[0054] After testing, the water vapor transmission rate of the film sheet provided in this example is 1.2 g / (m 2 ·24 h), the oxygen transmission rate is 0.5 cm 3 / (m 2·24 h·atm), the tensile strength is 18 MPa, and the yellowing index Δb is 1.0. It can be seen that the interlayer bonding of the diaphragm provided in this comparative example fails, the barrier property and mechanical properties decrease significantly, and the surface hardness decreases.

[0055] Comparative Example 2 A diaphragm of this comparative example is different from that of Example 1 in that antioxidants, ultraviolet absorbers, and light stabilizers are not added to all compositions, and the reduced component dosage is evenly increased to other components of this layer to ensure that the total amount remains unchanged, and the rest is the same as that of Example 1.

[0056] After testing, the water vapor transmission rate of the diaphragm provided in this example is 0.1 g / (m 2 ·24 h), and the oxygen transmission rate is 0.1 cm 3 / (m 2 ·24 h·atm), the tensile strength is 30 MPa, and the yellowing index Δb is 0.8. It can be seen that the diaphragm provided in this comparative example has poor weather resistance (Δb increases significantly), the coating peels off after xenon lamp aging, and the solvent resistance fails.

[0057] Comparative Example 3 A diaphragm of this comparative example is different from that of Example 1 in that the thickness of the intermediate layer (layer B) is 8 μm, and the rest is the same as that of Example 1.

[0058] After testing, the water vapor transmission rate of the diaphragm provided in this example is 0.5 g / (m 2 ·24 h), and the oxygen transmission rate is 0.3 cm 3 / (m 2 ·24 h·atm), and the tensile strength is 22 MPa. It can be seen that the too thin intermediate layer of the diaphragm provided in this comparative example results in a significant decrease in the barrier property, and the interfacial peeling is caused by the stress concentration between layers.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-barrier film sheet, characterized in that, It includes a first outer layer, an intermediate layer, and a second outer layer that are sequentially arranged from top to bottom; By weight, the first outer layer and the second outer layer independently include the following components: 100 - 1000 parts of polypropylene; 0.1 - 10 parts of initiator; 1 - 20 parts of antioxidant; 1 - 20 parts of ultraviolet absorber; 1 - 20 parts of light stabilizer; By weight, the intermediate layer includes the following components: 100 - 1000 parts of cycloolefin polymer; 0.5 - 15 parts of maleic anhydride; 1 - 20 parts of antioxidant; 1 - 20 parts of ultraviolet absorber; 1 - 20 parts of light stabilizer; The thicknesses of the first outer layer and the second outer layer are independently 5 - 250 μm.

2. The high-barrier diaphragm according to claim 1, wherein The polypropylene is isotactic or syndiotactic polypropylene with a melt index of 1.9 - 19 g / 10 min.

3. The high-barrier film sheet according to claim 1, wherein, The cycloolefin polymer is an amorphous transparent polymer copolymerized from cyclic olefin monomers and linear olefin monomers with a melt index of 1.8 - 50 g / 10 min.

4. The high-barrier film sheet according to claim 1, characterized in that, The total thickness of the high-barrier film sheet is 20 - 1000 μm, and the thickness of the intermediate layer is 10 - 600 μm.

5. The high-barrier diaphragm according to claim 1, characterized in that, The initiator is one or more of dicumyl peroxide and benzoyl peroxide.

6. The high-barrier film sheet according to claim 1, wherein The addition amount of maleic anhydride is 0.1% - 1.5% of the weight of the cycloolefin polymer.

7. A method for preparing a high-barrier film sheet, characterized in that, It includes the following steps: (1) Adopt a coextrusion process in the order of the first outer layer, the intermediate layer, and the second outer layer. The coextruded melt is cooled and shaped to obtain a sandwich-structured film layer; (2) Control the crystallinity through a cooling calender roll. The cooling and shaping temperature is 30 - 140 °C, and the surface roughness of the calender roll is 1.3 - 93.3 μm.

8. The preparation method of the high-barrier film sheet according to claim 7, wherein In step (1), the melt extrusion temperature of the first outer layer and the second outer layer is 220 - 260 °C, and the melt extrusion temperature of the intermediate layer is 200 - 250 °C.

9. The preparation method of the high-barrier film sheet according to claim 7, characterized in that, In step (2), the distance between the coextrusion die head and the cooling calender roll is 1 - 50 cm.

10. Use of the high-barrier film sheet according to any one of claims 1-6, characterized in that, For the preparation of drug packaging films or food packaging films, the water vapor transmission rate of the packaging film is ≤ 0.1 g / (m 2 ·24 h), and the oxygen transmission rate is ≤ 0.1 cm 3 / (m 2 ·24 h·atm).

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