Composite film, preparation method therefor and use thereof

Abstract

The present application discloses a composite film, a preparation method therefor and a use hereof. The composite film comprises a self-lubricating modified layer (100), an anti-hydrolysis modified layer (200) and a weather-resistant modified layer (300); the anti-hydrolysis modified layer (200) is located between the self-lubricating modified layer (100) and the weather-resistant modified layer (300); preparation raw materials of the self-lubricating modified layer (100), the anti-hydrolysis modified layer (200) and the weather-resistant modified layer (300) respectively comprise a first biodegradable material and a lubricant, a second biodegradable material and a chain extender, a third biodegradable material, an antioxidant, an ultraviolet absorber and a light stabilizer; and the first, second and third biodegradable materials independently comprise at least PBAT.

Description

Composite film and preparation method and application thereof

[0001] Cross-reference to related applications

[0002] The present application claims priority to the Chinese patent application No. 202410425420.8, filed on April 10, 2024, and entitled "Composite film and preparation method and application thereof", the whole content of the above patent application is incorporated herein by reference. TECHNICAL FIELD

[0003] The present application relates to the technical field of packaging materials, in particular to a composite film and a preparation method and application thereof. BACKGROUND

[0004] When polyethylene (such as low-density polyethylene, high-density polyethylene, foamed pearl wool) based packaging materials are used as dustproof and scratch-resistant film bags for household appliances (such as air conditioners, refrigerators, washing machines, etc.), inappropriate recycling methods and abandonment can lead to widespread plastic pollution and microplastic pollution in the natural environment.

[0005] In order to further improve the environmental friendly characteristics of packaging film materials for household appliances, while ensuring the good packaging performance of the packaging materials, various solutions have been proposed in the related fields of the industry. In the prior art, nano-zinc oxide is added as a reinforcing agent to improve the strength of PBAT (polybutylene adipate terephthalate), but the mechanical properties of the obtained PBAT film still cannot meet the requirements of packaging and transportation of household appliances. In the prior art, crystalline PLA and powder materials with lamellar structure characteristics are also added to make the film material have good water vapor barrier performance, but the mechanical properties are low, the life in good condition is only 12 months, the hydrolysis resistance is poor, and it is also difficult to meet the extreme storage environment requirements of household appliances. Moreover, these film materials still have the problem of insufficient self-lubricating performance, which can easily cause scratches on high-gloss appearance plastic parts, thereby affecting the appearance quality of the products.

[0006] SUMMARY

[0007] The present application aims to at least partially solve one of the above technical problems in the prior art, and one of the purposes of the present application is to provide a composite film.

[0008] A second purpose of the present application is to provide a preparation method of the above composite film.

[0009] A third purpose of the present application is to provide a packaging material having the above composite film.

[0010] A fourth purpose of the present application is to provide an application of the above composite film.

[0011] The first aspect of the present application provides a composite film, comprising a self-lubricating modified layer, a hydrolysis-resistant modified layer and a weather-resistant modified layer.

[0012] The hydrolysis-resistant modified layer is located between the self-lubricating modified layer and the weather-resistant modified layer.

[0013] The preparation raw material of the self-lubricating modified layer comprises a first biodegradable material and a lubricant.

[0014] The preparation raw material of the hydrolysis-resistant modified layer comprises a second biodegradable material and a chain extender.

[0015] The preparation raw material of the weather-resistant modified layer comprises a third biodegradable material, an antioxidant, an ultraviolet absorber and a light stabilizer; and

[0016] The first biodegradable material, the second biodegradable material and the third biodegradable material independently comprise at least PBAT.

[0017] According to some embodiments of the present application, the first biodegradable material, the second biodegradable material and the third biodegradable material are independently selected from PBAT, or are a combination of PBAT and at least one of PLA (poly lactic acid), PBS (polybutylene succinate), PBSA (polybutylene succinate-adipate), PHA (polyhydroxyalkanoate), PPC (polypropylene carbonate), and PGA (polyglycolic acid).

[0018] According to some embodiments of the present application, the composite film comprises, from inside to outside, the self-lubricating modified layer, the hydrolysis-resistant modified layer and the weather-resistant modified layer.

[0019] According to some embodiments of the present application, the mass ratio of the preparation raw material of the self-lubricating modified layer, the preparation raw material of the hydrolysis-resistant modified layer and the preparation raw material of the weather-resistant modified layer is 1:(0.8-1.2):(0.8-1.2).

[0020] According to some embodiments of the present application, the acid value of the hydrolysis-resistant modified layer is 3-8 mgKOH / g. The hydrolysis-resistant modified layer is a product prepared by using the second biodegradable material and the chain extender.

[0021] According to some embodiments of the present application, the mass percentage of the lubricant in the preparation raw material of the first biodegradable material is 0.5%-1.5%.

[0022] According to some embodiments of the present application, the lubricant comprises at least one of silicone oil, silicone powder, fatty acid amide, stearic acid, stearate, montanate, paraffin, polyethylene wax, erucic acid amide, oleic acid amide, ethylene bis-stearamide, pentaerythritol stearate, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer.

[0023] According to some embodiments of the present application, the mass percentage of the chain extender in the raw materials for preparing the second biodegradable material is 0.5% to 1.5%.

[0024] According to some embodiments of the present application, the chain extender comprises at least one of polycaprolactone and polybasic epoxy chain extender.

[0025] According to some embodiments of the present application, the mass percentage of the antioxidant, the ultraviolet absorber and the light stabilizer in the raw materials for preparing the third biodegradable material is independently 0.2% to 0.5%.

[0026] According to some embodiments of the present application, the antioxidant comprises at least one of hindered amine antioxidant and hindered phenol antioxidant.

[0027] According to some embodiments of the present application, the ultraviolet absorber comprises at least one of salicylate ultraviolet absorber, benzophenone ultraviolet absorber, benzotriazole ultraviolet absorber, substituted acrylonitrile ultraviolet absorber, triazine ultraviolet absorber and hindered amine ultraviolet absorber.

[0028] According to some embodiments of the present application, the light stabilizer comprises at least one of light screen, quencher and hindered amine light stabilizer.

[0029] According to some embodiments of the present application, the thickness of the composite film is 10 microns to 35 microns.

[0030] The second aspect embodiment of the present application provides a preparation method of the composite film of the first aspect embodiment of the present application, comprising the following steps:

[0031] The first biodegradable material and the lubricant are mixed to obtain a first component; the second biodegradable material and the chain extender are blended and modified to obtain a second component; the third biodegradable material, the antioxidant, the ultraviolet absorber and the light stabilizer are blended and modified to obtain a third component;

[0032] The first component, the second component and the third component are subjected to multi-layer co-extrusion blown film to obtain the composite film.

[0033] According to some embodiments of the present application, in the step of blending and modifying the second biodegradable material and the chain extender, the temperature of the blending and modification is 150°C to 170°C.

[0034] According to some embodiments of the present application, in the step of blending modification of the third biodegradable material, antioxidant, ultraviolet absorber and light stabilizer, the temperature of the blending modification is 150-170℃.

[0035] According to some embodiments of the present application, the extrusion temperature of the multi-layer co-extrusion blown film is 150-170℃.

[0036] A third aspect of the present application provides a packaging material comprising the composite film of the first aspect of the present application.

[0037] According to some embodiments of the present application, the packaging material is a dustproof bag or a scratchproof bag for household appliances.

[0038] A fourth aspect of the present application provides an application of the composite film of the first aspect of the present application in packaging or transportation of household appliances.

[0039] Additional aspects and advantages of the present application will be in part apparent and in part pointed out below. BRIEF DESCRIPTION OF DRAWINGS

[0040] FIG. 1 is a schematic diagram of a composite film structure according to an embodiment of the present application.

[0041] Reference signs:

[0042] a self-lubricating modified layer 100,

[0043] a hydrolysis-resistant modified layer 200, and

[0044] a weather-resistant modified layer 300. DETAILED DESCRIPTION

[0045] The embodiments of the present application are described in detail below with reference to the accompanying drawings. The embodiments described with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as a limitation of the present application.

[0046] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "thickness", "inner", "outer" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application. In addition, the features defined as "first", "second", "third" can explicitly or implicitly include one or more of the features.

[0047] One aspect of the present application provides a composite film. The composite film of the embodiments of the present application is described below with reference to FIG. 1.

[0048] Referring to FIG. 1, the composite film of the embodiments of the present application comprises a self-lubricating modified layer 100, a hydrolysis-resistant modified layer 200, and a weather-resistant modified layer 300. The hydrolysis-resistant modified layer 200 is located between the self-lubricating modified layer 100 and the weather-resistant modified layer 300. The raw material for preparing the self-lubricating modified layer 100 comprises a first biodegradable material and a lubricant. The raw material for preparing the hydrolysis-resistant modified layer 200 comprises a second biodegradable material and a chain extender. The raw material for preparing the weather-resistant modified layer 300 comprises a third biodegradable material, an antioxidant, an ultraviolet absorber, and a light stabilizer. The first biodegradable material, the second biodegradable material, and the third biodegradable material each independently comprises at least PBAT. The composite film prepared by using PBAT as the base material has good compostable degradation characteristics, mechanical properties, self-lubricating properties, hydrolysis resistance, and weather resistance, can protect the appearance of the product from scratches, and can effectively avoid appearance quality problems caused by friction between the film and the appearance of the product during packaging or transportation.

[0049] According to the embodiments of the present application, the first biodegradable material, the second biodegradable material, and the third biodegradable material are each independently selected from PBAT or a combination of PBAT and at least one of PLA, PBS, PBSA, PHA, PPC, and PGA. In some embodiments of the present application, the first biodegradable material, the second biodegradable material, and the third biodegradable material are each independently selected from PBAT or a combination of PBAT and at least one of PLA and PBS, i.e., a blended base material of PBAT and PLA / PBS. The biodegradable material can be PBAT alone or a composite material formed by using PBAT as the base material and combining with PLA, PBS, etc. These materials all have compostable degradation characteristics and can improve the environmental friendliness of the film material.

[0050] In some specific embodiments of the present application, the first biodegradable material is PBAT. The self-lubricating modified layer is prepared by using only PBAT, a single biodegradable material, which has a lower cost and the PBAT-based composite film material prepared thereby has good self-lubricating properties.

[0051] In some specific embodiments of the present application, the second biodegradable material is PBAT. The hydrolysis-resistant modified layer is prepared by using only PBAT, a single biodegradable material, which has a lower cost and the PBAT-based composite film material prepared thereby has good hydrolysis resistance.

[0052] In some specific embodiments of the present application, the third biodegradable material is PBAT. The weather-resistant modified layer is prepared by using only PBAT, a single biodegradable material, which has a lower cost and the PBAT-based composite film material prepared thereby has good weather resistance.

[0053] In some embodiments of the present application, the composite film of the present application comprises, from inside to outside, a self-lubricating modified layer 100, a hydrolysis-resistant modified layer 200, and a weather-resistant modified layer 300. In some specific embodiments of the present application, the composite film of the present application comprises, from the product contact surface to the exposed surface, a self-lubricating modified layer 100, a hydrolysis-resistant modified layer 200, and a weather-resistant modified layer 300, i.e., the self-lubricating modified layer 100 is the product contact surface, and the weather-resistant modified layer 300 is the exposed surface. By arranging the three basic layers of the self-lubricating modified layer 100, the hydrolysis-resistant modified layer 200, and the weather-resistant modified layer 300, each layer is used to improve the self-lubricating ability of the film material to protect the appearance of the product from scratches, improve the hydrolysis resistance of the PBAT film, and improve the weather resistance of the PBAT film. Specifically, to solve the problem that the film can cause scratches on the high-gloss appearance surface of the household appliance, the self-lubricating modified layer is arranged as the product contact surface, and the near-product layer is lubricated and modified to obtain a film material with good self-lubricating effect, thereby effectively avoiding the possible product appearance quality problems. For the packaging scenario where the film is exposed, by arranging the weather-resistant modified layer as the exposed surface, the weather resistance and light aging resistance of the composite film can be enhanced.

[0054] According to embodiments of the present application, the mass ratio of the preparation raw material of the self-lubricating modified layer, the preparation raw material of the hydrolysis-resistant modified layer, and the preparation raw material of the weather-resistant modified layer is 1:(0.8-1.2):(0.8-1.2). In some embodiments of the present application, the mass ratio of the preparation raw material of the self-lubricating modified layer, the preparation raw material of the hydrolysis-resistant modified layer, and the preparation raw material of the weather-resistant modified layer is 1:(0.9-1.1):(0.9-1.1). In some specific embodiments of the present application, the mass ratio of the preparation raw material of the self-lubricating modified layer, the preparation raw material of the hydrolysis-resistant modified layer, and the preparation raw material of the weather-resistant modified layer is 1:1:1, i.e., the three are in equal mass ratio. By using such a ratio to make a multi-layer composite film material, good packaging performance is achieved.

[0055] According to embodiments of the present application, the acid value of the hydrolysis-resistant modified layer is 3-8 mgKOH / g. In some embodiments of the present application, the acid value of the hydrolysis-resistant modified layer is 4-6 mgKOH / g. The hydrolysis-resistant modified layer with such an acid value has good hydrolysis resistance.

[0056] According to the embodiments of the present application, the mass percentage of the lubricant in the raw materials for preparing the first biodegradable material is 0.5% to 1.5%. In some examples, the mass percentage of the lubricant can be selected from 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, or 1.5%. By adding the lubricant in such a proportion in the raw materials for preparing the self-lubricating modification layer, the lubricating property of the PBAT material can be effectively improved, so that the PBAT-based film has good self-lubricating property, and the appearance quality problem caused by the friction between the film and the product appearance surface during transportation can be effectively avoided.

[0057] According to the embodiments of the present application, the lubricant includes at least one of silicone oil, silicone powder, fatty acid amide, stearic acid, stearate, montanate, paraffin, polyethylene wax, erucic acid amide, oleic acid amide, ethylene bis-stearamide, pentaerythritol stearate, ethylene-vinyl acetate copolymer, and ethylene-acrylic acid copolymer. In some embodiments of the present application, the lubricant includes at least one of silicone powder, fatty acid amide, stearic acid, stearate, erucic acid amide, oleic acid amide, ethylene bis-stearamide, and pentaerythritol stearate. The self-lubricating modification layer prepared by using these kinds of lubricants can have better self-lubricating property.

[0058] In some embodiments of the present application, the raw materials for preparing the self-lubricating modification layer are the first biodegradable material and the lubricant. In some examples, the first biodegradable material is PBAT. In this way, the PBAT-based composite film material prepared by using only PBAT and the lubricant to prepare the self-lubricating modification layer can have good self-lubricating property.

[0059] According to the embodiments of the present application, the mass percentage of the chain extender in the raw materials for preparing the second biodegradable material is 0.5% to 1.5%. In some examples, the mass percentage of the chain extender can be selected from 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, or 1.5%. By adding the chain extender in such a proportion in the raw materials for preparing the anti-hydrolysis modification layer, the acid value of the PBAT can be greatly reduced, and thus the hydrolysis resistance of the material can be greatly improved.

[0060] According to the embodiments of the present application, the chain extender includes at least one of polycaprolactone and a polybasic epoxy chain extender. The anti-hydrolysis modification layer prepared by using these kinds of chain extenders can have better hydrolysis resistance.

[0061] In some embodiments of the present application, the acid value of the second biodegradable material is 10 mgKOH / g-40 mgKOH / g. In some specific embodiments of the present application, the acid value of the second biodegradable material is 13 mgKOH / g-38 mgKOH / g. The raw material of the second biodegradable material has a high acid value and poor hydrolysis resistance, and therefore, by adding a chain extender for chain extension modification, the acid value of the second biodegradable material can be reduced, thereby effectively improving the hydrolysis resistance of the material.

[0062] In some embodiments of the present application, the raw material for preparing the anti-hydrolysis modified layer is the second biodegradable material and the chain extender. In some examples, the second biodegradable material is PBAT. In this way, only PBAT and a chain extender are used to prepare the anti-hydrolysis modified layer, and the PBAT-based composite film material prepared thereby can have good hydrolysis resistance.

[0063] According to embodiments of the present application, the mass percentage of the antioxidant, the ultraviolet absorber, and the light stabilizer in the raw material for preparing the third biodegradable material is independently 0.2%-0.5%. In some examples, the mass percentage of the antioxidant, the ultraviolet absorber, or the light stabilizer can be selected from 0.2%, 0.3%, 0.4%, or 0.5%, respectively. In the raw material for preparing the weather resistance modified layer, by adding an antioxidant, an ultraviolet absorber, and a light stabilizer in such a proportion, the weather resistance of the material can be improved.

[0064] According to embodiments of the present application, the antioxidant includes at least one of a hindered amine antioxidant and a hindered phenol antioxidant. In some embodiments of the present application, the antioxidant includes at least one of antioxidants 168, 245, 264, 300, 626, 702, 703, 1010, 1024, 1076, 1098, 1135, 2246, 3114, B215, B225, B900, B911. By using such a kind of antioxidant, the material can have good antioxidant effect.

[0065] According to embodiments of the present application, the ultraviolet absorber includes at least one of salicylate ultraviolet absorbers, benzophenone ultraviolet absorbers, benzotriazole ultraviolet absorbers, substituted acrylonitrile ultraviolet absorbers, triazine ultraviolet absorbers, hindered amine ultraviolet absorbers. In some embodiments of the present application, the ultraviolet absorber includes at least one of UV-P, UV-9, UV-21, UV-24, UV-104, UV-234, UV-242, UV-284, UV-292, UV-326, UV-327, UV-328, UV-329, UV-360, UV-531, UV-770, UV-5411. By using such a kind of ultraviolet absorber, the material can have good light aging resistance, and the weather resistance can be further improved to meet the requirements of exposed packaging scenarios.

[0066] According to embodiments of the present application, the light stabilizer includes at least one of light screening agents, quenching agents, hindered amine light stabilizers. In some embodiments of the present application, the light stabilizer includes at least one of light stabilizers 119, 292, 622, 770, 783, 791, 944. By using such a kind of light stabilizer, the material can have good light aging resistance, and the weather resistance can be further improved to meet the requirements of exposed packaging scenarios.

[0067] In some embodiments of the present application, the preparation raw material of the weather resistance modified layer is a third biodegradable material, an antioxidant, an ultraviolet absorber, and a light stabilizer. In some examples, the third biodegradable material is PBAT. In this way, only PBAT is used to prepare the weather resistance modified layer together with the antioxidant, the ultraviolet absorber, and the light stabilizer, and the prepared PBAT-based composite film material can have good weather resistance.

[0068] According to embodiments of the present application, the thickness of the composite film is 10 microns to 35 microns. In some embodiments of the present application, the thickness of the composite film is 12 microns to 32 microns. The composite film with such thickness has good compostable degradation characteristics, mechanical properties, self-lubricating properties, hydrolysis resistance, and weather resistance.

[0069] In some embodiments of the present application, the composite film has at least three layers, i.e., at least includes a self-lubricating modified layer, a hydrolysis resistance modified layer, and a weather resistance modified layer. In some specific embodiments of the present application, the composite film is made of a self-lubricating modified layer, a hydrolysis resistance modified layer, a weather resistance modified layer, and other modified materials, and the film material contains more than three layers of structure.

[0070] In some embodiments of the present application, the composite film has a transverse tensile strength of 30 MPa to 40 MPa. In some specific embodiments of the present application, the composite film has a transverse tensile strength of 32 MPa to 38 MPa.

[0071] In some embodiments of the present application, the composite film has a longitudinal tensile strength of 29-38 MPa. In some specific embodiments of the present application, the composite film has a longitudinal tensile strength of 30-36 MPa.

[0072] In some embodiments of the present application, the composite film has a transverse breaking elongation of 500-950%. In some specific embodiments of the present application, the composite film has a transverse breaking elongation of 540-940%.

[0073] In some embodiments of the present application, the composite film has a longitudinal breaking elongation of 270-350%. In some specific embodiments of the present application, the composite film has a longitudinal breaking elongation of 280-340%.

[0074] In some embodiments of the present application, the composite film has a fusion strength of 9-16 N / mm. In some specific embodiments of the present application, the composite film has a fusion strength of 10-15 N / mm.

[0075] Another aspect of the present application provides a method for preparing the composite film of the embodiments.

[0076] According to the embodiments of the present application, the method for preparing the composite film comprises the following steps:

[0077] The first biodegradable material and the lubricant are mixed to obtain a first component; the second biodegradable material and the chain extender are blended and modified to obtain a second component; the third biodegradable material, the antioxidant, the ultraviolet absorber, and the light stabilizer are blended and modified to obtain a third component;

[0078] The first component, the second component, and the third component are subjected to multi-layer co-extrusion blown film to obtain the composite film.

[0079] According to the embodiments of the present application, in order to solve the problem of insufficient mechanical properties of PBAT material, a multi-layer co-extruded PBAT film with better mechanical properties is obtained through the multi-layer co-extrusion scheme; the multi-layer co-extrusion technology realizes forced orientation of PBAT molecular chains in the transverse and longitudinal directions of the film material, thereby greatly improving the mechanical properties of the composite film, and forming a compostable film material with good packaging performance.

[0080] According to the embodiments of the present application, the first component forms a self-lubricating modified layer, the second component forms a hydrolysis-resistant modified layer, and the third component forms a weather-resistant modified layer.

[0081] According to embodiments of the present application, in the step of blending and modifying the second biodegradable material and the chain extender, the temperature of blending and modification is 150-170°C. In some embodiments of the present application, in the step of blending and modifying the second biodegradable material and the chain extender, the temperature of blending and modification is 150-160°C. In some examples, the temperature of blending and modification in this step can be selected from 150°C, 152°C, 155°C, 157°C or 160°C. By chain extension modification at such a processing temperature, the hydrolysis resistance of the anti-hydrolysis modified layer can be improved, and the hydrolysis resistance of the composite film can be improved.

[0082] According to embodiments of the present application, in the step of blending and modifying the third biodegradable material, the antioxidant, the ultraviolet absorber and the light stabilizer, the temperature of blending and modification is 150-170°C. In some embodiments of the present application, in the step of blending and modifying the third biodegradable material, the antioxidant, the ultraviolet absorber and the light stabilizer, the temperature of blending and modification is 150-160°C. In some examples, the temperature of blending and modification in this step can be selected from 150°C, 152°C, 155°C, 157°C or 160°C. By weather resistance modification at such a processing temperature, the weather resistance of the weather resistance modified layer can be improved, and the weather resistance of the composite film can be improved.

[0083] According to embodiments of the present application, the extrusion temperature of the multilayer co-extrusion blown film is 150-170°C. In some embodiments of the present application, the extrusion temperature of the multilayer co-extrusion blown film is 155-165°C. In some specific embodiments of the present application, the multilayer co-extrusion blown film is prepared in a multilayer co-extrusion blown film system, and the temperature of the feeding section, the compression section, the homogenization section and the die is controlled to be 153-157°C, 163-167°C, 163-167°C and 163-167°C, respectively. By multilayer co-extrusion at such a processing temperature, the mechanical properties of the PBAT-based composite film material can be greatly improved.

[0084] Another aspect of the present application provides a packaging material. According to embodiments of the present application, the packaging material comprises the composite film of the foregoing embodiments. The packaging material has good compostable degradation characteristics, mechanical properties, self-lubricating properties, hydrolysis resistance and weather resistance, can effectively avoid appearance quality problems of products, and can greatly improve the environmental friendly characteristics of the packaging material.

[0085] According to embodiments of the present application, the packaging material is a dustproof cover bag or a scratchproof cover bag for household appliances. As a dustproof cover bag or a scratchproof cover bag for household appliances, the packaging material has good environmental friendly characteristics and packaging performance, can meet the requirements of dustproof or scratchproof for household appliances, and can avoid appearance quality problems of household appliance products.

[0086] Another aspect of the present application provides the use of the composite film of the foregoing embodiments in the packaging or transportation of household appliances. The composite film has excellent environmental friendly properties and packaging performance, can meet the requirements of dustproof or scratchproof of household appliances, can effectively avoid the appearance quality problems of household appliances, and has a broad application prospect in the packaging and transportation of household appliances.

[0087] According to the foregoing embodiments of the present application, the household appliances include air conditioners, refrigerators or washing machines. These kinds of household appliances have white high light appearance surfaces, and the use of the composite film of the embodiments for packaging or transportation can protect the appearance of the household appliance products from scratches and avoid appearance quality problems in the packaging or transportation process.

[0088] The content of the present application is further described in detail through specific embodiments. The raw materials, reagents or devices used below can be obtained from conventional commercial channels unless otherwise specified. Unless otherwise specified, the test or test method is a conventional method in the art.

[0089] The raw materials used in the embodiments / comparative examples are described below:

[0090] Polycaprolactone, CAS: 24980-41-4;

[0091] Multi-epoxy chain extender, styrene-methyl methacrylate-glycidyl methacrylate copolymer, CAS: 1191261-43-4;

[0092] Multi-epoxy chain extender, BASF chain extender ADR-4468;

[0093] Hindered phenol antioxidant, XH-245, CAS: 36443-68-2;

[0094] Benzotriazole ultraviolet absorber, UV-360, CAS: 103597-45-1;

[0095] Light stabilizer, 119, CAS: 106990-43-6;

[0096] Lubricant, oleic acid amide, CAS: 301-02-0.

[0097] The above raw materials are all commercially available products and are used directly without further treatment.

[0098] The following test method standards are described as follows:

[0099] The mechanical properties and elongation at break are tested according to the standard GB / T 40933-2021 “Plastics Products - Films and Sheeting - Guide to Testing Thermoplastic Films”.

[0100] The reference standard for the fusion strength test is QB / T 2358-1998 "Plastic Film Packaging Bag Heat Seal Strength Test Method".

[0101] Example 1

[0102] In this example, PBAT with an acid value of 13.1 mgKOH / g is used as the base material, and 0.5% polycaprolactone chain extender based on the mass of PBAT is added for blending modification at a processing temperature of 150°C to obtain component 1. After testing, the acid value of component 1 is reduced to 4.3 mgKOH / g.

[0103] PBAT raw material, and 0.3% hindered phenol antioxidant, 0.3% benzotriazole ultraviolet absorber and 0.3% light stabilizer based on the mass of PBAT are blended and modified at a processing temperature of 150°C to obtain component 2.

[0104] PBAT raw material, and 1% lubricant based on the mass of PBAT are mixed to obtain component 3.

[0105] Components 1, 2 and 3 are fed into a multi-layer co-extrusion film blowing system in equal mass proportions, and the feeding section temperature, compression section temperature, homogenization section temperature and die temperature are 155°C, 165°C, 165°C and 165°C, respectively. The composite film of Example 1 is obtained by multi-layer co-extrusion blowing. The mass ratio of components 1, 2 and 3 is 1:1:1, and the thickness of the obtained composite film is about 25 microns.

[0106] After testing, the transverse tensile strength of the film of Example 1 can reach 36.10 MPa, the longitudinal tensile strength can reach 35.63 MPa, the transverse elongation at break can reach 938.51%, the longitudinal elongation at break can reach 333.67%, the fusion strength can reach 14.75 N / mm, the mechanical property (transverse / longitudinal tensile strength) retention rate can reach more than 75% after 192 hours of placement in an environment of 85°C and 85% humidity, the mechanical property (transverse / longitudinal tensile strength) retention rate can reach more than 85% after 24 months of placement in a conventional environment, the film can withstand more than 30 times of back-and-forth friction with a 1kg weight without scratching the high-gloss appearance panel of the air conditioner, and the degradable organic matter is greater than 90%.

[0107] Example 2

[0108] In this example, PBAT with an acid value of 20.8 mgKOH / g is used as the base material, and 1% styrene-methyl methacrylate-glycidyl methacrylate copolymer based on the mass of PBAT is added for blending modification at a processing temperature of 155°C to obtain component 1. After testing, the acid value of component 1 is reduced to 5.8 mgKOH / g.

[0109] PBAT raw material, and 0.2% hindered phenol antioxidant, 0.4% benzotriazole ultraviolet absorber and 0.3% light stabilizer were added according to the mass of PBAT, and were blended and modified at a processing temperature of 155°C to obtain component 2;

[0110] PBAT raw material, and 1% lubricant was added according to the mass of PBAT, and was mixed to obtain component 3;

[0111] Components 1, 2 and 3 were put into a multi-layer co-extrusion film blowing system in equal mass proportions, and a composite film of Example 2 was obtained by multi-layer co-extrusion blowing according to the feeding section temperature, compression section temperature, homogenization section temperature and die temperature of 155°C, 165°C, 165°C and 165°C, respectively. The mass ratio of components 1, 2 and 3 was 1:1:1, and the thickness of the obtained composite film was about 25 microns.

[0112] Testing showed that the transverse tensile strength of the film of Example 2 could reach 33.18 MPa, the longitudinal tensile strength could reach 30.28 MPa, the transverse elongation at break could reach 666.24%, the longitudinal elongation at break could reach 337.13%, the fusion strength could reach 12.72 N / mm, the mechanical property (transverse / longitudinal tensile strength) retention rate could reach more than 75% after being placed in an environment of 85°C and 85% humidity for 192 hours, the mechanical property (transverse / longitudinal tensile strength) retention rate could reach more than 85% after being placed in a conventional environment for 24 months, the film could be rubbed back and forth with a 1kg weight for more than 30 times without scratching the high-gloss appearance panel of the air conditioner, and the degradable organic matter was more than 90%.

[0113] Example 3

[0114] In this example, PBAT with an acid value of 37.2 mgKOH / g was used as the base material, and 1.5% of a multi-epoxy chain extender ADR-4468 was added according to the mass of PBAT, and was blended and modified at a processing temperature of 160°C to obtain component 1; testing showed that the acid value of component 1 was reduced to 4.9 mgKOH / g;

[0115] PBAT raw material, and 0.2% hindered phenol antioxidant, 0.4% benzotriazole ultraviolet absorber and 0.3% light stabilizer were added according to the mass of PBAT, and were blended and modified at a processing temperature of 155°C to obtain component 2;

[0116] PBAT raw material, and 1% lubricant was added according to the mass of PBAT, and was mixed to obtain component 3;

[0117] The component 1, component 2 and component 3 were put into a multi-layer co-extrusion film blowing system in equal mass proportions, and the composite film of Example 3 was obtained by multi-layer co-extrusion blowing according to the feeding section temperature, compression section temperature, homogenization section temperature and die temperature of 155℃, 165℃, 165℃ and 165℃ respectively. The mass ratio of component 1, component 2 and component 3 was 1:1:1, and the thickness of the obtained composite film was about 25 microns.

[0118] The film obtained in Example 3 was tested to have a transverse tensile strength of 32.47 MPa, a longitudinal tensile strength of 30.14 MPa, a transverse elongation at break of 542.14%, a longitudinal elongation at break of 287.34%, a fusion strength of 10.87 N / mm, a mechanical property (transverse / longitudinal tensile strength) retention rate of more than 75% after being placed in an environment of 85℃ and 85% humidity for 192 hours, a mechanical property (transverse / longitudinal tensile strength) retention rate of more than 85% after being placed in a conventional environment for 24 months, no scratches on the air conditioner high light appearance panel after the film was rubbed back and forth for more than 30 times under a load of 1 kg weight, and more than 90% of degradable organic matter.

[0119] Comparative Example 1

[0120] PBAT with an acid value of 13.1 mgKOH / g was used as the base material, and 1.5% of polycaprolactone chain extender based on the mass of PBAT was added for blending modification at a processing temperature of 150℃ to obtain component 1;

[0121] PBAT raw material, and 0.3% hindered phenol antioxidant, 0.3% benzotriazole ultraviolet absorber and 0.3% light stabilizer based on the mass of PBAT were added for blending modification at a processing temperature of 150℃ to obtain component 2;

[0122] The component 1, component 2 and PBAT raw material were put into a multi-layer co-extrusion film blowing system in equal mass proportions, and the composite film of Comparative Example 1 was obtained by multi-layer co-extrusion blowing according to the feeding section temperature, compression section temperature, homogenization section temperature and die temperature of 155℃, 165℃, 165℃ and 165℃ respectively. The outer layer was prepared from component 2, the middle layer was prepared from component 1, and the inner layer was prepared from PBAT raw material. The mass ratio of component 1, component 2 and PBAT raw material was 1:1:1, and the thickness of the obtained composite film was about 25 microns.

[0123] The film of the comparative example 1 has a transverse tensile strength of 36.57 MPa, a longitudinal tensile strength of 34.89 MPa, a transverse elongation at break of 920.78%, a longitudinal elongation at break of 327.15%, a fusion strength of 13.25 N / mm, a mechanical property (transverse / longitudinal tensile strength) retention rate of more than 75% after being placed in an environment of 85°C and 85% humidity for 192 hours, a mechanical property (transverse / longitudinal tensile strength) retention rate of more than 85% after being placed in a conventional environment for 24 months, obvious scratches on the air conditioner high-gloss appearance panel after the film is rubbed back and forth for more than 30 times under a load of 1 kg weight, and degradable organic matter of more than 90%.

[0124] Comparative example 2

[0125] The PBAT with an acid value of 13.1 mgKOH / g is used as a base material, 1.5% of polycaprolactone chain extender based on the mass of the PBAT is added, and blending modification is performed at a processing temperature of 150°C to obtain component 1; 0.3% of hindered phenol antioxidant, 0.3% of benzotriazole ultraviolet absorber, and 0.3% of light stabilizer are added based on the mass of the component 1, and blending modification is performed at a processing temperature of 150°C to obtain weather-resistant modified component 1.

[0126] The weather-resistant modified component 1 is put into an extrusion blow molding system, the feeding section temperature, the compression section temperature, the homogenization section temperature, and the die temperature are 155°C, 165°C, 165°C, and 165°C respectively, and a single-layer film of the comparative example 2 is obtained by extrusion blow molding. The thickness of the obtained single-layer film is about 25 microns.

[0127] The film of the comparative example 2 has a transverse tensile strength of 16.13 MPa, a longitudinal tensile strength of 28.30 MPa, a transverse elongation at break of 540.51%, a longitudinal elongation at break of 426.89%, a fusion strength of 7.97 N / mm, a mechanical property (transverse / longitudinal tensile strength) retention rate of more than 50% after being placed in an environment of 85°C and 85% humidity for 192 hours, a mechanical property (transverse / longitudinal tensile strength) retention rate of more than 70% after being placed in a conventional environment for 24 months, obvious scratches on the air conditioner high-gloss appearance panel after the film is rubbed back and forth for more than 30 times under a load of 1 kg weight, and degradable organic matter of more than 90%.

[0128] Comparative example 3

[0129] The PBAT with an acid value of 20.8 mgKOH / g is used as a base material, 1% of styrene-methyl methacrylate-glycidyl methacrylate copolymer based on the mass of the PBAT is added, and blending modification is performed at a processing temperature of 155°C to obtain component 1;

[0130] PBAT raw material, and 0.2% hindered phenol antioxidant, 0.4% benzotriazole ultraviolet absorber and 0.3% light stabilizer were added according to the mass of PBAT, and were blended and modified at a processing temperature of 155°C to obtain component 2.

[0131] Components 1, 2 and PBAT raw material were put into a multi-layer co-extrusion blown film system according to the equal mass ratio, and the feeding section temperature, compression section temperature, homogenization section temperature and die temperature were 155°C, 165°C, 165°C and 165°C respectively to obtain the composite film of Comparative Example 3 by multi-layer co-extrusion blowing. Among them, component 2 was prepared into the outer layer, component 1 was prepared into the middle layer, and PBAT raw material was prepared into the inner layer. The mass ratio of component 1, component 2 and PBAT raw material was 1:1:1, and the thickness of the obtained composite film was about 25 microns.

[0132] Tested, the film of Comparative Example 3 had a transverse tensile strength of 32.46 MPa, a longitudinal tensile strength of 30.87 MPa, a transverse elongation at break of 620.45%, a longitudinal elongation at break of 358.76%, a fusion strength of 13.05 N / mm, a mechanical property (transverse / longitudinal tensile strength) retention rate of more than 75% after being placed in an environment of 85°C and 85% humidity for 192 hours, a mechanical property (transverse / longitudinal tensile strength) retention rate of more than 85% after being placed in a conventional environment for 24 months, and obvious scratch marks on the air conditioner high light appearance panel after the film was rubbed back and forth with a 1kg weight for more than 30 times. The degradable organic matter was more than 90%.

[0133] Comparative Example 4

[0134] The film was blown from HDPE (high density polyethylene) as the base material, and the thickness of the film was about 25 microns.

[0135] Tested, the film of Comparative Example 4 had a transverse tensile strength of 22.14 MPa, a longitudinal tensile strength of 16.58 MPa, a transverse elongation at break of 237.15%, a longitudinal elongation at break of 140.30%, a fusion strength of 7.80 N / mm, a mechanical property (transverse / longitudinal tensile strength) retention rate of more than 90% after being placed in an environment of 85°C and 85% humidity for 192 hours, a mechanical property (transverse / longitudinal tensile strength) retention rate of more than 90% after being placed in a conventional environment for 24 months, and obvious scratch marks on the air conditioner high light appearance panel after the film was rubbed back and forth with a 1kg weight for more than 30 times. The degradable organic matter was 0.

[0136] The schematic diagram of the composite film structure prepared in Examples 1-3 can be seen in FIG. 1.

[0137] The test results of the film materials prepared in Examples 1-3 and Comparative Examples 1-4 are shown in Table 1 below.

[0138] Table 1 Film test results of examples and comparative examples

[0139] From the above test results, it can be seen that, compared with the existing polyethylene packaging material (see Comparative Example 4), the composite film of Examples 1-3 of the present application has better compostable degradation characteristics, mechanical properties, self-lubricating properties, hydrolysis resistance and weather resistance, and can protect the appearance of the product from scratches. Comparative Example 1 does not add a lubricant, which can cause obvious scratches on the high-gloss appearance panel of the air conditioner, resulting in appearance quality problems; Comparative Example 2 uses a single-layer film made of modified raw materials, which has poor mechanical properties and is not as good as the packaging performance of the examples; Comparative Example 3 differs from Example 2 only in that it does not add a lubricant. As can be seen from the test results, the high-gloss appearance panel of the air conditioner of Comparative Example 3 has significant scratches, while the high-gloss appearance panel of the air conditioner of Example 2 has no scratches. It can be seen that the film of Example 2 has self-lubricating properties and can protect the appearance of the product from scratches.

[0140] The preparation of the weather-resistant modified layer of the composite film of the examples of the present application adds antioxidants, ultraviolet absorbers and light stabilizers. The addition of ultraviolet absorbers and light stabilizers is to meet the requirements of exposed packaging materials. By adding ultraviolet absorbers and light stabilizers, the light aging resistance of the composite film can be enhanced. If no ultraviolet absorbers and light stabilizers are added for light resistance modification, the film samples without light aging resistance will be broken within the same light aging test time.

[0141] The examples of the present application use a variety of modified materials to prepare the composite film, which has no effect on the original parts, the size, angle, number and specifications of the parts. However, after using this composite film with compostable degradation characteristics, the environmental friendliness of the material can be greatly improved.

[0142] The composite film with excellent environmental friendliness and packaging performance provided by the examples of the present application can be used as a packaging material. For example, this composite film can be used as a dustproof and scratch-resistant film bag for air conditioners, refrigerators, washing machines and other household appliances, which can meet the dustproof or scratch-resistant requirements of these household appliances and avoid appearance quality problems of household appliance products. This composite film has broad application prospects in the packaging or transportation of household appliances.

[0143] In the description of the specification, reference to "some embodiments," "some implementations," or "some examples," etc., means that a particular feature, structure, material, or characteristic being described is included in at least one embodiment or example of the application. The appearances of the phrases "in some embodiments," "in some implementations," or "in some examples," etc. in various places in the specification are not necessarily all referring to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics being described can be combined in any suitable manner in one or more embodiments or examples.

[0144] Although embodiments of the application have been illustrated and described, it will be clear to those of ordinary skill in the art that various changes, modifications, substitutions, and alterations can be made therein without departing from the principles and the scope of the application, which are defined by the claims and their equivalents.

Claims

1. A composite film comprising a self-lubricating modified layer, a hydrolysis-resistant modified layer and a weather-resistant modified layer, wherein: The anti-hydrolysis modified layer is located between the self-lubricating modified layer and the weathering modified layer; The raw materials for preparing the self-lubricating modified layer include a first biodegradable material and a lubricant; The raw materials for preparing the hydrolysis-resistant modified layer include a second biodegradable material and a chain extender; The raw materials for preparing the weather-resistant modified layer include a third biodegradable material, an antioxidant, an ultraviolet absorber and a light stabilizer; and The first biodegradable material, the second biodegradable material, and the third biodegradable material independently include at least PBAT.

2. A composite film according to claim 1, wherein The first biodegradable material, the second biodegradable material, and the third biodegradable material are independently selected from PBAT, or a combination of PBAT and at least one of PLA, PBS, PBSA, PHA, PPC, and PGA.

3. A composite film according to claim 1 or 2, wherein The composite film comprises a self-lubricating modified layer, an anti-hydrolysis modified layer and a weather-resistant modified layer which are sequentially arranged from the inside to the outside.

4. A composite film according to any one of claims 1 to 3, wherein: The mass ratio of the raw materials for preparing the self-lubricating modified layer, the raw materials for preparing the anti-hydrolysis modified layer and the raw materials for preparing the weathering modified layer is 1:(0.8-1.2):(0.8-1.2).

5. A composite film according to any one of claims 1 to 4, wherein: The acid value of the hydrolysis-resistant modified layer is 3 mgKOH / g to 8 mgKOH / g.

6. A composite membrane according to any one of claims 1 to 5, wherein: The mass percentage of the lubricant to the mass percentage of the raw materials for preparing the first biodegradable material is 0.5% to 1.5%.

7. A composite membrane according to claim 6, wherein: The lubricant includes at least one of silicone oil, silicone powder, fatty acid amide, stearic acid, stearate, montanate, paraffin, polyethylene wax, erucamide, oleamide, ethylene bisstearamide, pentaerythritol stearate, ethylene-vinyl acetate copolymer, and ethylene-acrylic acid copolymer.

8. A composite membrane according to any one of claims 1 to 7, wherein: The mass percentage of the chain extender to the mass percentage of the raw materials for preparing the second biodegradable material is 0.5% to 1.5%.

9. A composite membrane according to claim 8, wherein: The chain extender includes at least one of polycaprolactone and polyvalent epoxy chain extender.

10. A composite membrane according to any one of claims 1 to 9, wherein: The weight percentage of the antioxidant, the ultraviolet absorber and the light stabilizer to the weight percentage of the raw materials for preparing the third biodegradable material is 0.2% to 0.5%.

11. A composite membrane according to claim 10, wherein: The antioxidant includes at least one of a hindered amine antioxidant and a hindered phenol antioxidant.

12. A composite membrane according to claim 10 or 11, wherein: The ultraviolet absorber includes at least one of a salicylate ultraviolet absorber, a benzophenone ultraviolet absorber, a benzotriazole ultraviolet absorber, a substituted acrylonitrile ultraviolet absorber, a triazine ultraviolet absorber, and a hindered amine ultraviolet absorber.

13. A composite membrane according to any one of claims 10 to 12, wherein: The light stabilizer includes at least one of a light shielding agent, a quencher, and a hindered amine light stabilizer.

14. A composite membrane according to any one of claims 1 to 13, wherein: The thickness of the composite film is 10 microns to 35 microns.

15. A method for preparing the composite membrane according to any one of claims 1 to 14, comprising the following steps: mixing a first biodegradable material and a lubricant to obtain a first component; blending and modifying a second biodegradable material and a chain extender to obtain a second component; blending and modifying a third biodegradable material, an antioxidant, an ultraviolet absorber, and a light stabilizer to obtain a third component; as well as The first component, the second component and the third component are subjected to multi-layer co-extrusion blown film to obtain the composite film.

16. The preparation method according to claim 15, wherein In the step of blending and modifying the second biodegradable material and the chain extender, the blending and modification temperature is 150° C. to 170° C.

17. The preparation method according to claim 15 or 16, wherein In the step of blending and modifying the third biodegradable material, the antioxidant, the ultraviolet absorber and the light stabilizer, the blending and modification temperature is 150° C. to 170° C.

18. The preparation method according to any one of claims 15 to 17, wherein: The extrusion temperature of the multi-layer co-extrusion blown film is 150° C. to 170° C.

19. A packaging material comprising the composite film according to any one of claims 1 to 14.

20. The packaging material according to claim 19, wherein The packaging material is a dust-proof bag or an anti-scratch bag for household appliances.

21. Use of the composite film according to any one of claims 1 to 14 in the packaging or transportation of household appliances.

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