WO2023115599A1 - Degradable high-barrier composite film and preparation method therefor - Google Patents

Abstract

A degradable high-barrier composite film has a layer structure of one of A/B, A/C, A/B/C, and A/B/A/C. The layer A is a modified polyterephthalic acid-adipate-butylene copolymer, and contains the following components by mass: 50-103 parts of polyterephthalic acid-adipate-butylene copolymer, 20-109 parts of thermoplastic starch, 2-10 parts of compatibilizer, 0.5-10 parts of tackifier, and 1.5-42 parts of auxiliary material; the layer B is paper or a cellulose film; and the layer C is a composite material, and contains the following components by mass: 40-150 parts of fully biodegradable polymer, 12-60 parts of reinforcing filler, 2-16 parts of antistatic agent, and 0.1-15 parts of ultraviolet light absorber. The composite film has good barrier property and relatively high interlayer peel strength, and can be applied to the field of packaging of liquid and fresh foods.

Description

[Title of the invention established by ISA under Rule 37.2] Degradable high-barrier composite film and its preparation method technical field

The invention relates to a degradable high-barrier composite film and a preparation method thereof, belonging to the field of packaging films.

Background technique

High barrier packaging is critical to extending the shelf life and shelf life of food, pharmaceuticals and cosmetics. In order to achieve multiple functions such as water barrier, oxygen barrier, upright, light-proof, low-temperature heat sealing, etc., usually high-barrier packaging uses aluminum foil and plastic film as the barrier layer, polyethylene or polypropylene as the heat-sealing layer and printing layer, and paper as the middle layer , Composite materials formed by dry or extrusion compounding processes. The rapid marketization of paper-aluminum-plastic composite flexible packaging has provided great convenience to people’s daily life, but at the same time, composite flexible packaging with different materials and characteristics is difficult to separate and recycle through physical means, and is basically a disposable packaging material. Some of them are landfilled or incinerated as general domestic waste, which brings great pressure to the environment; while the long-fiber pulp, polyethylene and high-quality aluminum materials used to prepare composite packaging materials still have high use value after use, and direct disposal also causes A lot of resources are wasted. Therefore, the development of new composite flexible packaging materials has far-reaching and important social significance and economic value.

Biodegradable composite flexible packaging is an environmentally friendly packaging material that combines fully biodegradable materials of different materials and functions to give the contents good protection and aesthetics. This type of composite flexible packaging can be directly buried after being discarded. Under specific composting conditions and It can be completely degraded into biomass, carbon dioxide and water within a degradable time limit, providing a solution for reducing the carbon footprint of composite plastic flexible packaging.

However, due to the insufficient barrier performance of the degradable material itself, many technical solutions have adopted a composite solution with traditional non-degradable materials. For example, CN113427867A discloses a high-barrier polylactic acid-based film with a five-layer composite structure. Molecular weight polylactic acid, the barrier layer is ethylene-vinyl alcohol copolymer (EVOH) or ethylene-vinyl acetate copolymer (EVA), this composite film combines degradable materials with high barrier traditional plastic EVOH. CN112706484A discloses a high-barrier polyvinyl alcohol (PVA) composite film, including a functional layer and an outer layer, and the functional layer is an alternating structure of thermoplastic polyvinyl alcohol two-dimensional nano-layers and EVOH two-dimensional nano-layers assembled by multiple layers. The EVOH in these solutions is a non-degradable material, and the resulting composite flexible packaging still needs to be separated and recycled after disposal, which cannot completely solve the plastic pollution problem caused by the composite flexible packaging, and also makes the degradable components in it meaningless.

There are also a small number of public reports on the use of fully degradable components to meet the barrier performance requirements, but basically all involve newly developed special processing equipment, supplemented by complex processes, and it is difficult to industrialize at this stage. For example CN112159544A discloses a kind of environmental protection degradable high barrier film of three-layer structure, and barrier layer is positioned at the middle of two base layers, and barrier layer is made of propylene carbonate, nano mesoporous material and dispersant, and base layer is then made of butylene adipate - Composition of butylene terephthalate copolymer, plasticizer, polyacrylate, polypropylene carbonate and polycaprolactone/polyvinylpyrrolidone blend, formed by melt extrusion processing and biaxial stretching process Three-layer coextruded structural membrane. In this process, in order to improve the tensile strength of the film, a biaxial stretching process is used to process the biodegradable film. This process and equipment are expensive and complicated, and are not yet mature in the field of biodegradable film processing.

Contents of the invention

The purpose of the present invention is to solve a series of shortcomings in the background technology, and specifically solve the problems of complex processing, difficult recycling of different materials and high prices in the field of food composite packaging.

In order to achieve the above object, in the first aspect, the present invention provides a degradable high barrier composite film, which has a layer structure of one of A/B, A/C, A/B/C and A/B/A/C , the A layer is a modified polybutylene terephthalate-adipate copolymer, comprising the following mass components: 50-103 parts of polybutylene terephthalate-adipate copolymer, 20-109 parts of thermoplastic starch, 2-10 parts of compatibilizer, 0.5-10 parts of tackifier, 1.5-42 parts of auxiliary materials; the B layer is paper or cellulose film; the C layer is a composite material, including the following Quality components: 40-150 parts of fully biodegradable polymer, 12-60 parts of reinforcing filler, 2-16 parts of antistatic agent, 0.1-15 parts of ultraviolet absorber.

Further, the thermoplastic starch plasticizer is at least two of glycerin, citric acid, stearic acid, formamide, urea, sorbitol, ethylene glycol, acetyl tributyl citrate and epoxidized soybean oil.

Further, the gelatinization temperature of the thermoplastic starch is 50-120°C.

Further, the compatibilizer is succinic anhydride, maleic anhydride grafted polyterephthalic acid-adipate-butylene copolymer, ethylene-methyl acrylate-glycidyl methacrylate, γ-aminopropyl At least one of triethoxysilane, γ-glycidyloxypropyltrimethoxysilane, γ-(methacryloyloxy)propyltrimethoxysilane, titanate coupling agent.

Further, the tackifier is at least one of ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, sodium lignosulfonate, diphenylmethane diisocyanate and DuPont's Biomax strong 120.

Further, the fully biodegradable polymer is polyhydroxyalkanoate, polyε-caprolactone, polybutylene succinate, polysuccinate-adipate-butylene copolymer, polylactic acid - at least two of caprolactone copolymer, polyglyceryl sebacate, polybutylene terephthalate-co-succinate and polypropylene carbonate.

Further, the reinforcing filler is carbon nanotubes, graphene, white lignin, cellulose nanocrystals, nano-intercalation montmorillonite, kaolin, nano-calcium carbonate, cellulose nano-whiskers, amorphous nano-scale white carbon black , at least one of food-grade talcum powder.

Further, the antistatic agent is trihydroxyethylmethyl quaternary ammonium methyl sulfate, octadecyl dimethyl quaternary ammonium nitrate, alkylamide nonionic surfactant, alkyl phosphate, Alkyl Sulfate, Stearyl Trimethyl Ammonium Chloride and Stearyl Dimethyl Ammonium Chloride, (Lauramidopropyl Trimethylamine) Sulfate Potassium Ester Salt, N,N-Bis(2- Hydroxyethyl)-N-(3'dodecyloxy-2'hydroxypropyl)methanamine potassium sulfate, trihydroxyethyl methyl quaternary ammonium sulfate potassium ester, N,N-hexadecyl At least one of ethyl morpholine sulfate ethyl ester salts.

Further, the ultraviolet absorber is phenyl o-hydroxybenzoate, 2,4-dihydroxybenzophenone, 2-hydroxyl-4-methoxybenzophenone, 2-hydroxyl-4-n-octyloxy benzophenone, 2-(2'-hydroxy-3',5'-di-tert-phenyl)-5-chlorinated benzotriazole, resorcinol monobenzoate, 2'-2'- Thiobis(4-tert-octylphenoxy)nickel, tris(1,2,2,6,6-pentamethylpiperidinyl)phosphite, 4-benzoyloxy-2,2,6 , at least one of 6-tetramethylpiperidine, 2,4,6-tris(2'-butoxyphenyl)-1,3,5-triazine, and hexamethylphosphoric triamide.

In a second aspect, the present invention provides a method for preparing a degradable high-barrier composite film, comprising the following steps: S1: dry the starch at 60°C for 12-48 hours and weigh it with a plasticizer in a ratio of 100:(10-40) Add to the high-speed mixer and stir for 2-10 minutes. During the mixing process, cooling water is passed through the inner wall of the machine to cool the material temperature. Put the mixed material into the extruder for melting, mixing, cooling and pelletizing. The temperature from the feeding section to the extruder head is 80-150°C, the feeding speed is 3-10rpm, and the screw speed is 50-400rpm/min. The melt pressure is 2-10MPa, the traction and pelletizing speeds are 20-60rpm/min and 7-20rpm/min respectively, and after pelletizing, a thermoplastic material for modifying polybutylene terephthalate adipate copolymer is obtained. starch;

S2: Mix the thermoplastic starch granules described in S1, polybutylene terephthalate adipate, compatibilizer, tackifier and auxiliary materials, extrude and granulate, and then blow mold into a film through an extruder, blow the film The operating temperature of each temperature zone of the machine is 80-200°C, the speed of the main machine is 40-200rpm/min, and sequentially undergoes melting, plasticizing, pressurizing, cooling, pulling, trimming and winding to obtain the A layer;

S3: Unwind layer B above the layer A film obtained in S2, heat layer A and layer B through cooling composite rolls for stretch transfer, and press together through calender rolls to obtain A/B structure composite film;

S4: Add fully biodegradable polymers, reinforcing fillers, antistatic agents and UV absorbers into the multi-feed extrusion system for melt blending and granulation, and the cooled pellets are put into the first extrusion of the multi-layer composite production line In the machine, the pellets are melted and plasticized to form a uniform fluid, and a cast film is formed through a flat die as the C layer;

S5: Stretch and transfer the cast film obtained in S4, and place the A-layer film obtained in S2 above the cast film, and the two are pressed together by a calender roll to obtain an A/C structure composite film;

S6: Unwind layer B above the cast film obtained in S4, and press the two together through calender rolls to obtain a composite film with a B/C structure;

S7: After heating and cooling the composite roll of the A-layer film obtained in S2, carrying out stretch transfer with the B/C composite film obtained in S6 for secondary calendering and compounding, the composite film of the A/B/C structure is obtained;

S8: Unwind the A-layer film obtained in S2 on both sides of the B-layer film, in which the B-layer film is the main unwinding, heat the A-layer film obtained in S2, stretch and transfer it, and calender and compound it with the B-layer film to obtain A/B /A structure composite film;

S9: After performing corona treatment on the A side of the A/B/A composite film obtained in S8, the material obtained in S4 is stretched and transferred to the second secondary heating and cooling composite roll, and rolled together by the composite roll to obtain the A/B /A/C Structural Composite Materials,

S10: Corona, winding, cutting, and packaging are performed on the materials obtained in S3, S5, S7, and S9 to obtain the degradable high-barrier composite film.

Compared with prior art, the beneficial effect of the present invention is:

(1) The use of thermoplastic starch to fill polybutylene terephthalate adipate copolymer reduces the production cost of degradable resins and increases its barrier properties to water vapor, and can ensure its durability in the natural environment that can indicate a deadline Compostability;

(2) When the composite flexible packaging material has expired, the composite film does not need to be chemically separated, and it can be directly processed through composting, which helps to solve the problem that the current composite flexible packaging recycled materials are difficult to recycle;

(3) The composite film has good barrier properties and high interlayer peel strength, and can be applied to the packaging field of liquid and fresh foods.

Detailed ways

The present invention is described in further detail in conjunction with embodiment now, and the application of the present invention is not limited to following embodiment, and any form modification of the present invention all will fall into protection domain of the present invention.

The composition of each layer of A, B, and C in Examples 1-5 is shown in Table 1.

A, B, C layer composition in the embodiment 1-5 of table 1

Example 1

A biodegradable high-barrier composite film has an A/C double-layer structure.

The layer A has a thickness of 50 μm and is processed from modified polybutylene terephthalate-adipate copolymer particles with an average particle size of 1 mm, an intrinsic viscosity ([η]) of 0.9 dl/g, and a molecular weight of 150,000 become. The A layer includes the following components in parts by weight: 50 parts of polybutylene terephthalate-adipate copolymer, 60 parts of thermoplastic starch, 2 parts of ethylene-methyl acrylate-glycidyl methacrylate , 3.1 parts of ethylene-vinyl acetate copolymer, 1.5 parts of auxiliary materials.

The C layer has a thickness of 6 μm and contains the following components in parts by mass: 23 parts of polyglycerol sebacate, 17 parts of polylactic acid-caprolactone copolymer, 4 parts of cellulose nanocrystals, and 9 parts of carbon nanotubes , 12.8 parts of trihydroxyethylmethyl quaternary ammonium methyl sulfate, 3.2 parts of N,N-hexadecyl ethyl morpholine ethyl sulfate salt and tris(1,2,2,6,6-pentamethylpipene 0.1 part of pyridyl) phosphite.

The preparation method of above-mentioned degradable high-barrier composite film, comprises the following steps:

S1: Dry the starch with a linearity of 20% at 60°C for 12 hours, weigh it with glycerin and stearic acid in a ratio of 40:15:5, add it to a high-speed mixer and stir for 2 minutes, and pass cooling water through the inner wall of the machine during the mixing process. The gelatinization temperature was maintained at 50°C. Put the mixed material into the extruder for melting, mixing, cooling and pelletizing. The temperature from the feeding section to the extruder head is 110-150°C, the feeding speed is 5rpm, the screw speed is 400rpm/min, and the melt pressure is 2 -5MPa, traction and pelletizing speeds are 20rpm/min and 19rpm/min respectively. Obtain the thermoplastic starch for modified polybutylene terephthalate adipate copolymer after pelletizing;

S2: The thermoplastic starch granules described in S1, polybutylene terephthalate-adipate, ethylene-methyl acrylate-glycidyl methacrylate, ethylene-vinyl acetate copolymer, antibacterial agent, anti-blocking agent and water After the lubricant is mixed, it is extruded and granulated, and then blown into a film by the extruder. Traction, edge trimming and winding to obtain the A layer;

S3: Polyglyceryl sebacate, polylactic acid-caprolactone copolymer, cellulose nanocrystals, carbon nanotubes, trihydroxyethylmethyl quaternary ammonium methosulfate, N,N-hexadecyl ethyl Morpholine ethyl sulfate and tris(1,2,2,6,6-pentamethylpiperidinyl) phosphite are added to the multi-feed extrusion system for melt blending and granulation, and the cooled pellets are put into In the first extruder of the multi-layer composite production line, the pellets are melted and plasticized to form a uniform fluid, and a cast film is formed through a flat die as the C layer;

S4: Stretching transfer of the obtained cast film, and at the same time, layer A is placed on the cast film, and the two are pressed together by a calender roll to obtain an A/C structure composite film;

S5: Winding, cutting, and packaging the material obtained in S4 to obtain the degradable high-barrier composite film.

Example 2

A biodegradable high-barrier composite film has an A/B/C three-layer structure.

The layer A has a thickness of 55 μm, and is processed from modified polybutylene terephthalate-adipate copolymer particles with an average particle diameter of 3 mm, an intrinsic viscosity ([η]) of 1.2 dl/g, and a molecular weight of 100,000 become. The A layer includes the following components in parts by weight: 103 parts of polybutylene terephthalate-adipate copolymer, 20 parts of thermoplastic starch, 3 parts of γ-aminopropyltriethoxysilane, seaweed 0.5 parts of sodium bicarbonate, 26.3 parts of auxiliary materials.

The B layer has a thickness of 400 μm and is made of cellulose film.

The C layer has a thickness of 230 μm and contains the following components in parts by mass: 12 parts of polylactic acid-caprolactone copolymer, 50 parts of polyhydroxyalkanoate, 10 parts of nano-intercalated montmorillonite, 2 parts of carbon nanotubes 5.6 parts of N,N-hexadecylethylmorpholine ethyl sulfate and 5 parts of tris(1,2,2,6,6-pentamethylpiperidinyl)phosphite.

The preparation method of above-mentioned degradable high-barrier composite film, comprises the following steps:

S1: Dry the starch with a straight chain degree of 28% at 60°C for 12 hours, weigh it with glycerin and urea at a ratio of 14:1:5, add it to a high-speed mixer and stir for 5 minutes, and pass cooling water through the inner wall of the machine during the mixing process to make the paste The melting temperature was kept at 50 °C. Put the mixed material into the extruder for melting, mixing, cooling and pelletizing. The temperature from the feeding section to the extruder head is 110-130°C, the feeding speed is 7rpm, the screw speed is 300rpm/min, and the melt pressure is 3 -8MPa, traction and pelletizing speeds are 30rpm/min and 20rpm/min respectively. Obtain the thermoplastic starch for modified polybutylene terephthalate adipate copolymer after pelletizing;

S2: After mixing the thermoplastic starch granules described in S1, polybutylene terephthalate-adipate, γ-aminopropyltriethoxysilane, sodium alginate, antibacterial agent, anti-blocking agent and slip agent Extrusion granulation, and then blown into film by extruder. The operating temperature of each temperature zone of the blown film machine is 110-140 ℃, the main engine speed is 400Hz, and it undergoes melting, plasticizing, pressurizing, cooling, pulling, and trimming in sequence. and winding to obtain the A layer;

S3: Polylactic acid-caprolactone copolymer, polyhydroxyalkanoate, nano-intercalation montmorillonite, carbon nanotubes, N,N-hexadecyl ethyl morpholine ethyl sulfate salt and three (1, 2,2,6,6-Pentamethylpiperidinyl) phosphite is added to the multi-feed extrusion system for melt blending and granulation, and the cooled pellets are put into the first extruder of the multi-layer composite production line , to melt and plasticize the pellets to form a uniform fluid, and form a cast film through a flat die as the C layer;

S4: Unwind layer B above the cast film of layer C, and press the two together by calender rolls to obtain a composite film of B/C structure;

S5: Heat and cool the layer A film obtained in S2 for stretch transfer, and then perform secondary calendering and compounding with the B/C structure composite film obtained in S4 to obtain the A/B/C structure composite film.

S6: Corona, winding, cutting, and packaging are performed on the material obtained in S3 to obtain the degradable high-barrier composite film.

Example 3

A biodegradable high-barrier composite film has an A/B double-layer structure.

The layer A has a thickness of 100 μm, and is processed from modified polybutylene terephthalate-adipate copolymer particles with an average particle size of 2 mm, an intrinsic viscosity ([η]) of 1.5 dl/g, and a molecular weight of 180,000 become. The A layer includes the following components in parts by weight: 80 parts of polybutylene terephthalate-adipate copolymer, 30 parts of thermoplastic starch, 6 parts of γ-aminopropyltriethoxysilane, ethylene - 8.6 parts of vinyl acetate copolymer, 35.5 parts of auxiliary materials.

The B layer has a thickness of 300 μm and is made of paper.

The preparation method of above-mentioned degradable high-barrier composite film, comprises the following steps:

S1: Dry the starch with a linearity of 25% at 60°C for 48 hours, weigh it with stearic acid and urea at a ratio of 30:9:4, add it to a high-speed mixer and stir for 8 minutes, and pass cooling water through the inner wall of the machine during the mixing process. The gelatinization temperature was maintained at 120°C. Put the mixed material into the extruder for melting, mixing, cooling and pelletizing. The temperature from the feeding section to the extruder head is 110-150°C, the feeding speed is 10rpm, the screw speed is 400rpm/min, and the melt pressure is 8 -10MPa, traction and pelletizing speeds are 35rpm/min and 20rpm/min respectively. Obtain the thermoplastic starch for modified polybutylene terephthalate adipate copolymer after pelletizing;

S2: The thermoplastic starch granules described in S1, polybutylene terephthalate-adipate copolymer, thermoplastic starch, γ-aminopropyltriethoxysilane, ethylene-vinyl acetate copolymer, antibacterial agent, The anti-blocking agent and slip agent are mixed, extruded and granulated, and then blown into a film by the extruder. Pressing, cooling, pulling, edge trimming and winding to obtain the A layer;

S3: Unwind layer B above layer A, heat layer A and layer B through cooling composite rolls for stretch transfer, and press together through calender rolls to obtain A/B structure composite films;

S4: Corona, winding, cutting, and packaging are performed on the material obtained in S3 to obtain the degradable high-barrier composite film.

Example 4

A biodegradable high-barrier composite film has an A/B/A/C four-layer structure.

The A layer has a thickness of 80 μm, and is processed from modified polybutylene terephthalate-adipate copolymer particles with an average particle diameter of 4 mm, an intrinsic viscosity ([η]) of 1.3 dl/g, and a molecular weight of 120,000. become. The A layer includes the following components in parts by weight: 85 parts of polybutylene terephthalate-adipate copolymer, 80 parts of thermoplastic starch, 10 parts of ethylene-methyl acrylate-glycidyl methacrylate, 10 parts of sodium alginate, 42 parts of auxiliary materials.

The thickness of the B layer is 260 μm, and the material is cellulose film.

The C layer has a thickness of 300 μm and contains the following components in parts by mass: 130 parts of polyglycerol sebacate, 20 parts of polyhydroxyalkanoate, 5 parts of cellulose nanocrystals, and 15 parts of nano-intercalated montmorillonite , 30 parts of carbon nanotubes, 2 parts of N,N-hexadecyl ethyl morpholine ethyl sulfate, 2.9 parts of phenyl o-hydroxybenzoate and tris(1,2,2,6,6-pentamethylpipene 12.1 parts of pyridyl) phosphite.

The preparation method of above-mentioned degradable high-barrier composite film, comprises the following steps:

S1: Dry the starch with a linearity of 22% at 60°C for 36 hours, weigh it with stearic acid and urea in a ratio of 51:22:7, add it to a high-speed mixer and stir for 10 minutes, and pass cooling water through the inner wall of the machine during the mixing process. The gelatinization temperature was maintained at 100°C. Put the mixed material into the extruder for melting, mixing, cooling and pelletizing. The temperature from the feeding section to the extruder head is 100-140°C, the feeding speed is 3rpm, the screw speed is 200rpm/min, and the melt pressure is 2 -4MPa, traction and pelletizing speeds are 15rpm/min and 8rpm/min respectively. Obtain the thermoplastic starch for modified polybutylene terephthalate adipate copolymer after pelletizing;

S2: The thermoplastic starch granules described in S1, polybutylene terephthalate-adipate copolymer, thermoplastic starch, ethylene-methyl acrylate-glycidyl methacrylate, sodium alginate, antibacterial agent, opening The film blowing machine is blown into a film after being mixed with the lubricant and slip agent, and then blown into a film. , cooling, traction, edge trimming and winding to obtain the A layer;

S3: Polyglyceryl sebacate, polyhydroxyalkanoate, cellulose nanocrystals, nanointercalation montmorillonite, carbon nanotubes, N,N-hexadecylethylmorpholine ethyl sulfate, ortho Phenyl hydroxybenzoate and tris(1,2,2,6,6-pentamethylpiperidinyl) phosphite are added to the multi-feed extrusion system for melt blending and granulation, and the cooled pellets are put into multi-layer In the first extruder of the composite production line, the pellets are melted and plasticized to form a uniform fluid, and a cast film is formed through a flat die as the C layer;

S4: Unwind the A-layer film obtained in S2 on both sides of the B-layer film, in which the B-layer film is the main unwinding, heat, stretch and transfer the A-layer film obtained in S2, and then calender and compound it with the B-layer film to obtain A/B /A structure composite film.

S5: After performing corona treatment on the A side of the A/B/A composite film obtained in S4, the material obtained in S3 is stretched and transferred to the second secondary heating and cooling composite roll, and rolled together by the composite roll to obtain the A/B /A/C Structural Composite.

S6: performing corona, winding, cutting, and packaging on the material obtained in S5 to obtain the degradable high-barrier composite film.

Example 5

A biodegradable high-barrier composite film has an A/B/A/C four-layer structure.

The layer A has a thickness of 95 μm, and is processed from modified polybutylene terephthalate-adipate copolymer particles with an average particle diameter of 5 mm, an intrinsic viscosity ([η]) of 1.5 dl/g, and a molecular weight of 140,000. become. The A layer includes the following components in parts by weight: 80 parts of polybutylene terephthalate-adipate copolymer, 109 parts of thermoplastic starch, 7 parts of γ-aminopropyltriethoxysilane, alginic acid 6.4 parts of sodium, 31.2 parts of excipients.

The thickness of the B layer is 50 μm, and the material is cellulose film.

The C layer has a thickness of 160 μm and contains the following components in parts by mass: 45 parts of polyglycerol sebacate, 65 parts of polylactic acid-caprolactone copolymer, 10 parts of cellulose nanocrystals, nano-intercalation montmorillonite 50 parts of soil, 9.7 parts of trihydroxyethylmethyl quaternary ammonium methosulfate, and 8.5 parts of tris(1,2,2,6,6-pentamethylpiperidinyl) phosphite.

The preparation method of above-mentioned degradable high-barrier composite film, comprises the following steps:

S1: Dry starch with a straight chain degree of 27% at 60°C for 48 hours, weigh it with glycerin and urea at a ratio of 80:11:18, add it to a high-speed mixer and stir for 7 minutes, and pass cooling water through the inner wall of the machine during the mixing process to make the paste The melting temperature was maintained at 120 °C. Put the mixed material into the extruder for melting, mixing, cooling and pelletizing. The temperature from the feeding section to the extruder head is 80-130°C, the feeding speed is 5rpm, the screw speed is 340rpm/min, and the melt pressure is 2 -5MPa, traction and pelletizing speeds are 7rpm/min and 10rpm/min respectively. Obtain the thermoplastic starch for modified polybutylene terephthalate adipate copolymer after pelletizing;

S2: Mix the thermoplastic starch granules described in S1, polybutylene terephthalate-adipate copolymer, γ-aminopropyltriethoxysilane, sodium alginate, antibacterial agent, anti-blocking agent and slip agent After extruding and granulating, it is blown into film by extruder. Edge and winding, to obtain the A layer;

S3: Polyglyceryl sebacate, polylactic acid-caprolactone copolymer, cellulose nanocrystals, nanointercalation montmorillonite, trihydroxyethylmethyl quaternary ammonium methosulfate and tris(1,2, 2,6,6-pentamethylpiperidinyl) phosphite is added to the multi-feed extrusion system for melt blending and granulation, and the cooled pellets are put into the first extruder of the multi-layer composite production line to make The pellets are melted and plasticized to form a uniform fluid, and a cast film is formed through a flat die as the C layer;

S4: Unwind the A-layer film obtained in S2 on both sides of the B-layer film, in which the B-layer film is the main unwinding, heat, stretch and transfer the A-layer film obtained in S2, and then calender and compound it with the B-layer film to obtain A/B /A structure composite film.

S5: After performing corona treatment on the A side of the A/B/A composite film obtained in S4, the material obtained in S3 is stretched and transferred to the second secondary heating and cooling composite roll, and rolled together by the composite roll to obtain the A/B /A/C Structural Composite.

S6: performing corona, winding, cutting, and packaging on the material obtained in S5 to obtain the degradable high-barrier composite film.

Experimental example

Prepare A/C, A/B/C, A/B and A/B/A/C composite films according to the method of this example, and then place the composite films under the conditions of predetermined temperature and humidity Peel test. The test results of biodegradation rate, water vapor transmission rate, oxygen transmission rate and peel strength are shown in Table 2.

Biodegradation rate, oxygen transmission rate, water vapor transmission rate and peel strength of multilayer composite film in table 2 embodiment 1-5

The biodegradation rate of the composite film in Examples 1-5 is ≥74% within 6 months, which meets the requirement in GB/T 20197-2006 that the biodegradation rate of biodegradable plastics should be ≥61%. The oxygen transmission rate and water vapor transmission rate of this type of composite film are in line with the requirements of food packaging films in GB/T 28117-2011. The oxygen transmission rate and water vapor transmission rate should be lower than 20cm ³ /m ² ·24h·0.1MPa and 30 (g/m ² ·24h) requirements. The peel strength of the food composite packaging film should generally be ≥ 3.0N/15mm, and the peel strength between the layers of the composite films in Examples 1-5 all meet the requirements. Therefore, the degradable high-barrier composite film of the present invention has the potential to be applied to food packaging that requires higher barrier properties.

The above description is only a schematic scheme of the principle of the present invention, and does not impose other formal restrictions on the structure of the present invention. The unexpressed part defaults to adopting schemes known in the art, and any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention still belong to the scope of the technical scheme of the present invention.

Claims (10)

A degradable high-barrier composite film, characterized in that it has a layer structure of one of A/B, A/C, A/B/C and A/B/A/C, and the A layer is modified Polybutylene terephthalate-adipate copolymer, comprising the following mass components: 50-103 parts of polybutylene terephthalate-adipate copolymer, 20-109 parts of thermoplastic starch, and 2-10 parts of compatibilizer, 0.5-10 parts of tackifier, 1.5-42 parts of auxiliary materials; The B layer is paper or cellulose film; The C layer is a composite material, comprising the following mass components: 40-150 parts of fully biodegradable polymer, 12-60 parts of reinforcing filler, 2-16 parts of antistatic agent, and 0.1-15 parts of ultraviolet absorber. The degradable high-barrier composite film according to claim 1, wherein the plasticizer of the thermoplastic starch is glycerin, citric acid, stearic acid, formamide, urea, sorbitol, ethylene glycol, acetyl lemon At least two of tributyl ester and epoxidized soybean oil. The degradable high-barrier composite film according to claim 1, characterized in that the gelatinization temperature of the thermoplastic starch is 50-120°C. The degradable high-barrier composite film according to claim 1, wherein the compatibilizer is succinic anhydride, maleic anhydride grafted polyterephthalic acid-adipate-butylene copolymer, ethylene- Methyl Acrylate-Glycidyl Methacrylate, γ-Aminopropyltriethoxysilane, γ-Glycidyloxypropyltrimethoxysilane, γ-(Methacryloxy)propyltrimethoxysilane , At least one of titanate coupling agents. The degradable high-barrier composite film according to claim 1, wherein the tackifier is ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, sodium lignosulfonate, diphenylmethane diisocyanate and Dupont At least one of the company's Biomax strong 120. The degradable high-barrier composite film according to claim 1, wherein the fully biodegradable polymer is polyhydroxyalkanoate, polyε-caprolactone, polybutylene succinate, polybutylene Diacid-adipate-butylene copolymer, polylactic-caprolactone copolymer, polyglyceryl sebacate, polybutylene terephthalate-co-succinate, and polypropylene carbonate At least two of the The degradable high-barrier composite film according to claim 1, wherein the reinforcing filler is carbon nanotubes, graphene, white lignin, cellulose nanocrystals, nano-intercalation montmorillonite, kaolin, nanocarbonic acid At least one of calcium, cellulose nano-whiskers, amorphous nano-scale white carbon black, and food-grade talcum powder. The degradable high-barrier composite film according to claim 1, wherein the antistatic agent is trihydroxyethylmethyl quaternary ammonium methosulfate, octadecyldimethyl quaternary ammonium nitrate, alkane Amide-based nonionic surfactants, alkyl phosphates, alkyl sulfates, stearyl trimethylammonium chloride and stearyl dimethylpentylammonium chloride, (lauroyl amidopropyl trimethyl Amine) potassium sulfate, N,N-bis(2-hydroxyethyl)-N-(3'dodecyloxy-2'hydroxypropyl)methanamine potassium sulfate, trihydroxyethylmethyl At least one of quaternary ammonium sulfate potassium ester salt and N,N-hexadecylethylmorpholine ethyl sulfate salt. The degradable high-barrier composite film according to claim 1, wherein the ultraviolet absorber is phenyl o-hydroxybenzoate, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxy benzophenone, 2-hydroxy-4-n-octyloxybenzophenone, 2-(2'-hydroxy-3',5'-di-tert-phenyl)-5-chlorinated benzotriazole, Resorcinol monobenzoate, 2'-2'-thiobis(4-tert-octylphenoxy)nickel, tris(1,2,2,6,6-pentamethylpiperidinyl)phosphite Esters, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, 2,4,6-tris(2'-butoxyphenyl)-1,3,5-triazine , at least one of hexamethylphosphoric triamide. A method for preparing a degradable high-barrier composite film, comprising the following steps: S1: Dry the starch at 60°C for 12-48 hours and weigh it with the plasticizer at a ratio of 100: (10-40) and add it to a high-speed mixer and stir for 2-10 minutes. During the mixing process, cooling water is passed through the inner wall of the machine to cool the material. . Put the mixed material into the extruder for melting, mixing, cooling and pelletizing. The temperature from the feeding section to the extruder head is 80-150°C, the feeding speed is 3-10rpm, and the screw speed is 50-400rpm/min. The melt pressure is 2-10MPa, the traction and pelletizing speeds are 20-60rpm/min and 7-20rpm/min respectively, and after pelletizing, the thermoplastic material used for modifying polybutylene terephthalate adipate copolymer is obtained. starch; S2: Mix the thermoplastic starch granules described in S1, polybutylene terephthalate adipate, compatibilizer, tackifier and auxiliary materials, extrude and granulate, and then blow mold into a film through an extruder, blow the film The operating temperature of each temperature zone of the machine is 80-200°C, the speed of the main machine is 40-200rpm/min, and sequentially undergoes melting, plasticizing, pressurizing, cooling, pulling, trimming and winding to obtain the A layer; S3: Unwind layer B above the layer A film obtained in S2, heat layer A and layer B through cooling composite rolls for stretch transfer, and press together through calender rolls to obtain A/B structure composite film; S4: Add fully biodegradable polymers, reinforcing fillers, antistatic agents and UV absorbers into the multi-feed extrusion system for melt blending and granulation, and the cooled pellets are put into the first extrusion of the multi-layer composite production line In the machine, the pellets are melted and plasticized to form a uniform fluid, and a cast film is formed through a flat die as the C layer; S5: Stretch and transfer the cast film obtained in S4, and place the A-layer film obtained in S2 above the cast film, and the two are pressed together by a calender roll to obtain an A/C structure composite film; S6: Unwind layer B above the cast film obtained in S4, and press the two together through calender rolls to obtain a composite film with a B/C structure; S7: heating and cooling the layer A film obtained in S2, stretching and transferring it to the B/C composite film obtained in S6, and performing secondary calendering and compounding to obtain the A/B/C structure composite film; S8: Unwind the A-layer film obtained in S2 on both sides of the B-layer film, in which the B-layer film is the main unwinding, heat the A-layer film obtained in S2, stretch and transfer it, and calender and compound it with the B-layer film to obtain A/B /A structure composite film; S9: After performing corona treatment on the A side of the A/B/A composite film obtained in S8, the material obtained in S4 is stretched and transferred to the second secondary heating and cooling composite roll, and rolled together by the composite roll to obtain the A/B /A/C Structural Composite Materials, S10: Corona, winding, cutting, and packaging are performed on the materials obtained in S3, S5, S7, and S9 to obtain the degradable high-barrier composite film.