Biodegradable modified atmosphere film with multi-layer structure

Abstract

The invention aims to solve the manufacturing problem of a biodegradable air-conditioning film, and discloses a biodegradable air-conditioning film with a multilayer structure, the biodegradable air-conditioning film comprises a first surface layer, a middle layer and a second surface layer, the air-conditioning film is sequentially formed by the first surface layer, the middle layer and the second surface layer through a co-extrusion process, and the first surface layer and the second surface layer are prepared from polylactic acid (PLA), polycaprolactone (PCL), polylactic acid (PLA), polycaprolactone (PCL) and polylactic acid (PLA). The biodegradable plastic polyester is one or more of poly (butylene terephthalate) or butylene adipate (PBAT), poly (butylene succinate) (PBS) and polyhydroxyalkanoate (PHA), the functional master batch is used as an auxiliary material (the addition amount is greater than or equal to 1%), and a small amount of auxiliary agent (the addition amount is less than 1%) is added; the middle layer takes polycarbon dioxide (PPC) as a main material, takes functional master batch as an auxiliary material (the addition amount is greater than or equal to 1%), and is added with a small amount of auxiliaries (the addition amount is less than 1%). The composite film is produced through a three-layer film co-extrusion process, meanwhile, a co-blowing process can be carried out, in-mold compounding and out-mold compounding can be carried out, and operation is more convenient.

Description

Technical Field

[0001] The invention relates to the field of controlled atmosphere films, and in particular to a biodegradable controlled atmosphere film with a multi-layer structure. Background Art

[0002] With the increasing attention paid to the environment and the implementation of the global plastic ban, degradable plastic film is a material that is in urgent need in the market, gradually replacing non-degradable plastic film. For the existing mainstream PBAT, PLA, PBS, PPC, etc., there are functional deficiencies in single materials in blow molding. They are improved and upgraded through the method of blending and modification. The application of plastic film in ground film is to use polyethylene resin or biodegradable resin. Polyethylene resin is difficult to decompose in the natural environment and will remain in the land for a long time, causing soil compaction. Biodegradable film can be safely biodegraded, but its anti-aging and heat resistance are poor. Degradable film is also used in food packaging. We know that keeping moisture is the key to keeping vegetables fresh. Polyolefin film is usually a good water barrier material, but another problem with keeping vegetables fresh is that they need oxygen and emit carbon dioxide, so there is a modified atmosphere film. However, the current modified atmosphere film has a single functionality and cannot meet the current packaging needs. Therefore, the inventor invented a multi-layer biodegradable modified atmosphere film to solve the packaging problem. Summary of the invention

[0003] The purpose of the present invention is to solve the deficiencies of the prior art and provide a biodegradable gas-controlled membrane with a multi-layer structure.

[0004] The present invention is achieved through the following technical solutions:

[0005] A multi-layer biodegradable gas-controlled film comprises a first surface layer, a middle layer and a second surface layer, wherein the gas-controlled film is sequentially formed by the first surface layer, the middle layer and the second surface layer through a co-extrusion process, wherein the first surface layer and the second surface layer are mainly made of one or more biodegradable plastic polyesters selected from polylactic acid (PLA), polycaprolactone (PCL), polybutylene terephthalate or adipate (PBAT), polybutylene succinate (PBS) and polyhydroxyalkanoate (PHA), with a functional masterbatch as an auxiliary material (addition amount ≥1%), and a small amount of auxiliary agent (addition amount <1%) is added; the middle layer is mainly made of polycarbonate (PPC), with a functional masterbatch as an auxiliary material (addition amount ≥1%), and a small amount of auxiliary agent (addition amount <1%) is added.

[0006] Preferably, the functional masterbatch is an auxiliary material (addition amount ≥ 1%), and the biodegradability of the organic component should be ≥ 60%.

[0007] Preferably, the functional masterbatch comprises 5-20% of an acrylic resin copolymer with an epoxy functional group, wherein the monomer composition of the copolymer is 55-85% of styrene (St) or methyl methacrylate (MMA); 15-45% of glycidyl methacrylate (GMA); 1-10% of butyl acrylate (BA); a single component or multiple components of polycaprolactone (PCL), polyterephthalic acid, polybutylene adipate (PBAT), polybutylene succinate (PBS) or polyhydroxyalkanoate (PHA), with a total amount of 30-70%; 20-40% of polylactic acid (PLA); 3-5% of silica; 2-4% of erucamide or oleamide; 2-4% of vinyl bisstearamide (EBS); and other components, including antioxidants, stearates (magnesium salts, calcium salts), anti-hydrolysis agents, etc., are all within 1%.

[0008] Preferably, the acrylic resin copolymer with epoxy functional groups is produced by polymerization processes such as bulk polymerization, solution polymerization, suspension polymerization and emulsion polymerization, and the weight average molecular weight (Mw) of the copolymer is achieved in the range of 5000-50000 by controlling the polymerization temperature, polymerization time and the amount of initiator or chain transfer agent added.

[0009] Preferably, the thickness of the intermediate layer is adjustable, and the auxiliary materials and additives are adjustable.

[0010] Compared with the prior art, the present invention has the following beneficial effects:

[0011] The present invention controls the gas conditioning function by adjusting the thickness of the middle layer and the auxiliary materials and additives. The invention is produced by a three-layer film co-extrusion process and a co-blowing process. The in-mold compounding and the out-of-mold compounding are possible, and the operation is more convenient. The addition of the functional masterbatch makes the biodegradability of the organic components greater than 60%, so that the degradation can be effectively carried out to meet the requirements of degradable plastics. The manufacturing process and equipment are simple and suitable for large-scale production. The invention is applied to automatic packaging films, packaging bag films and industrial materials, etc., and can meet the demand for degradable plastics. PLA is a new type of bio-based, renewable biodegradable material, which is processed by using starch from renewable plant resources. The starch raw material is saccharified to obtain glucose, and then the glucose and a certain strain of bacteria are fermented to produce high-purity lactic acid, and then a certain molecular weight of polylactic acid is obtained by a chemical synthesis method. The polylactic acid will have good biodegradability, and can be completely degraded by microorganisms in nature under specific conditions after use and disposal, and finally generate carbon dioxide and water without polluting the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a structural schematic diagram of the present invention.

[0013] Explanation of reference numerals: 1, first surface layer, 2, middle layer, 3, second surface layer. DETAILED DESCRIPTION

[0014] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0015] Example 1

[0016] See also Figure 1 , the present invention provides a technical solution:

[0017] A multi-layer biodegradable gas-controlled film comprises a first surface layer 1, an intermediate layer 2 and a second surface layer 3. The gas-controlled film is sequentially formed by the first surface layer 1, the intermediate layer 2 and the second surface layer 3 through a co-extrusion process, wherein the first surface layer 1 and the second surface layer 3 are mainly made of a variety of biodegradable plastic polyesters such as polylactic acid (PLA), polycaprolactone (PCL), polybutylene terephthalate or adipate (PBAT), polybutylene succinate (PBS) and polyhydroxyalkanoate (PHA), with a functional masterbatch as an auxiliary material (addition amount ≥1%), and a small amount of auxiliary agent (addition amount <1%) is added; the intermediate layer 2 is mainly made of polycarbonate (PPC), with a functional masterbatch as an auxiliary material (addition amount ≥1%), and a small amount of auxiliary agent (addition amount <1%) is added.

[0018] The functional masterbatch is an auxiliary material (addition amount ≥ 1%), and the biodegradability of the organic component should be ≥ 60%.

[0019] The functional masterbatch comprises 5-20% of an acrylic resin copolymer with epoxy functional groups, wherein the monomer composition of the copolymer comprises 55-85% of methyl methacrylate (MMA); 15-45% of glycidyl methacrylate (GMA); 1-10% of butyl acrylate (BA); a multi-component of polycaprolactone (PCL), polyterephthalic acid, polybutylene adipate (PBAT), polybutylene succinate (PBS) or polyhydroxyalkanoate (PHA), with a total amount of 30-70%; 20-40% of polylactic acid (PLA); 3-5% of silicon dioxide; 2-4% of oleamide; 2-4% of vinyl bisstearamide (EBS); and other components, including antioxidants, stearates (magnesium salts, calcium salts), anti-hydrolysis agents, etc., all within 1%.

[0020] The acrylic resin copolymer with epoxy functional groups is produced by polymerization processes such as bulk polymerization, solution polymerization, suspension polymerization and emulsion polymerization, and the weight average molecular weight (Mw) of the copolymer is achieved in the range of 5000-50000 by controlling the polymerization temperature, polymerization time and the amount of initiator or chain transfer agent added.

[0021] The thickness of the intermediate layer 2 is adjustable, and the auxiliary materials and additives are adjustable.

[0022] The first surface layer, the middle layer and the second surface layer are formed in proportion through a co-extrusion process, wherein PLA is a new type of bio-based, renewable biodegradable material, which is processed using starch extracted from renewable plant resources. The starch raw material is saccharified to obtain glucose, which is then fermented with glucose and certain bacteria to produce high-purity lactic acid, and then polylactic acid of a certain molecular weight is obtained through a chemical synthesis method. The polylactic acid will have good biodegradability and can be completely degraded by microorganisms in nature under specific conditions after use and disposal, and finally generates carbon dioxide and water without polluting the environment.

[0023] The preparation method of the multi-layer biodegradable gas-controlled film:

[0024] The first surface layer, the second surface layer and the middle layer as well as the functional masterbatch and the additives are cold mixed in a high-speed mixer to achieve mixing of the materials;

[0025] The mixed materials are mixed and extruded using a mixer, wherein the mixer is a single-screw extruder or a twin-screw extruder, to obtain a blended material;

[0026] The obtained blend is formed into a modified atmosphere film through a co-extrusion process.

[0027] Example 2

[0028] A multi-layer biodegradable gas-controlled film comprises a first surface layer 1, an intermediate layer 2 and a second surface layer 3, wherein the first surface layer 1 and the second surface layer 3 are mainly made of a biodegradable plastic polyester selected from polylactic acid (PLA), polycaprolactone (PCL), polyterephthalic acid, polybutylene succinate (PBS) and polyhydroxyalkanoate (PHA), with a functional masterbatch as an auxiliary material (addition amount ≥1%), and a small amount of auxiliary agent (addition amount <1%) is added; the intermediate layer 2 is mainly made of polycarbonate (PPC), with a functional masterbatch as an auxiliary material (addition amount ≥1%), and a small amount of auxiliary agent (addition amount <1%) is added.

[0029] The functional masterbatch is an auxiliary material (addition amount ≥ 1%), and the biodegradability of the organic component should be ≥ 60%.

[0030] The functional masterbatch comprises 5-20% of an acrylic resin copolymer with epoxy functional groups, wherein the monomer composition of the copolymer comprises 55-85% of methyl methacrylate (MMA); 15-45% of glycidyl methacrylate (GMA); 1-10% of butyl acrylate (BA); a single component of polycaprolactone (PCL), polyterephthalic acid, polybutylene adipate (PBAT), polybutylene succinate (PBS) or polyhydroxyalkanoate (PHA), with a total amount of 30-70%; 20-40% of polylactic acid (PLA); 3-5% of silicon dioxide; 2-4% of oleamide; 2-4% of vinyl bisstearamide (EBS); and other components, including antioxidants, stearates (magnesium salts, calcium salts), anti-hydrolysis agents, etc., all within 1%.

[0031] The degradation effects of single components such as polycaprolactone (PCL), polyterephthalic acid, polybutylene adipate (PBAT), polybutylene succinate (PBS) or polyhydroxyalkanoate (PHA) were compared with those of multi-component mixtures. The experiment showed that the degradation effect of multi-component mixtures was greater, which was 1.3 times that of a single component.

[0032] This specific embodiment is only an explanation of the present invention, not a limitation of the present invention. After reading this specification, those skilled in the art can make non-creative modifications to this embodiment as needed, but as long as it is within the scope of the claims of the present invention, it is protected by the patent law.

Claims

1. A multi-layer biodegradable modified atmosphere film, comprising a first surface layer, an intermediate layer and a second surface layer, wherein the modified atmosphere film is sequentially formed by a co-extrusion process from the first surface layer, the intermediate layer and the second surface layer, wherein the first surface layer and the second surface layer are mainly made of one or more biodegradable plastic polyesters selected from polylactic acid (PLA), polycaprolactone (PCL), polybutylene terephthalate or adipate (PBAT), polybutylene succinate (PBS), and polyhydroxyalkanoate (PHA), with a functional masterbatch as an auxiliary material (added amount ≥1%), and a small amount of additives (added amount <1%) are added; the intermediate layer is mainly made of polycarbonate (PPC), with a functional masterbatch as an auxiliary material (added amount ≥1%), and a small amount of additives (added amount <1%) are added.

2. The multi-layer biodegradable modified atmosphere membrane according to claim 1, characterized in that: The functional masterbatch is an auxiliary material (addition amount ≥ 1%), and the biodegradability of the organic component should be ≥ 60%.

3. The multi-layer biodegradable modified atmosphere membrane according to claim 1, characterized in that: The functional masterbatch comprises 5-20% of an acrylic resin copolymer with epoxy functional groups, wherein the monomer composition of the copolymer comprises 55-85% of styrene (St) or methyl methacrylate (MMA); 15-45% of glycidyl methacrylate (GMA); 1-10% of butyl acrylate (BA); a single component or multiple components of polycaprolactone (PCL), polyterephthalic acid, polybutylene adipate (PBAT), polybutylene succinate (PBS) or polyhydroxyalkanoate (PHA), with a total amount of 30-70%; 20-40% of polylactic acid (PLA); 3-5% of silicon dioxide; 2-4% of erucamide or oleamide; 2-4% of vinyl bisstearamide (EBS); and other components, including antioxidants, stearates (magnesium salts, calcium salts), anti-hydrolysis agents, etc., all within 1%.

4. The multi-layer biodegradable modified atmosphere film according to claim 3, characterized in that: The acrylic resin copolymer with epoxy functional groups is produced by polymerization processes such as bulk polymerization, solution polymerization, suspension polymerization and emulsion polymerization, and the weight average molecular weight (Mw) of the copolymer is achieved in the range of 5000-50000 by controlling the polymerization temperature, polymerization time and the amount of initiator or chain transfer agent added.

5. The multi-layer biodegradable modified atmosphere film according to claim 1, characterized in that: The thickness of the middle layer is adjustable, and the auxiliary materials and additives are adjustable.

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