CN112959782B

CN112959782B - Completely degradable gas barrier air cushion film with excellent processing performance and preparation method thereof

Info

Publication number: CN112959782B
Application number: CN202110160030.9A
Authority: CN
Inventors: 涂宗铃; 陈赐辉; 蔡佳煌
Original assignee: Xiamen Ameson New Material Inc
Current assignee: Xiamen Ameson New Material Inc
Priority date: 2021-02-05
Filing date: 2021-02-05
Publication date: 2023-02-10
Anticipated expiration: 2041-02-05
Also published as: CN112959782A

Abstract

The invention relates to the technical field of plastic films, in particular to a completely degradable gas barrier air cushion film with excellent processing performance and a preparation method thereof. It comprises an outer layer, a middle layer and an inner layer; the thickness ratio of the outer layer to the middle layer to the inner layer is 40: (10-20): (35-55); the gas barrier air cushion film is prepared from degradable materials; the preparation raw materials of the outer layer, the middle layer and the inner layer comprise polymethyl ethylene carbonate; the raw materials for preparing the outer layer also comprise inorganic filler and PBAT, and the content of the inorganic filler accounts for at least 30wt% of the raw materials for preparing the outer layer. The regulation and control of the components, the proportion, the physical and chemical parameters of the components and the like of the three layers of the inner layer and the outer layer effectively improve the heat seal strength, the barrier property and the heat seal property of the buffer air cushion film. In addition, the air cushion film provided by the invention has excellent processing performance, the problems of cylinder film adhesion, bag making scalding, dimensional stability and the like caused by temperature resistance difference between the inner layer raw material and the outer layer raw material are effectively avoided, and the production efficiency and the yield of products are greatly improved.

Description

Completely degradable gas barrier air cushion film with excellent processing performance and preparation method thereof

Technical Field

The invention relates to the technical field of plastic films, in particular to a completely degradable gas barrier air cushion film with excellent processing performance and a preparation method thereof.

Background

With the development of the e-commerce industry, the usage of the buffer air cushion film is increased dramatically day by day. At present, most of barrier buffer air cushion films with barrier property on the market are produced by adopting PE/PA composite materials, and although good economic benefit is brought by excellent mechanical property and barrier property, the environmental pollution is increasingly aggravated due to the nondegradable property of the barrier buffer air cushion films. Along with the sustainable development of society, the demand of people on the development of low-carbon economy is increasingly urgent, and the development of fully-degradable buffer packaging materials becomes a necessary trend.

In order to solve the problems, the chinese patent CN103804879 discloses a high-barrier polypropylene carbonate-based composite film material and a preparation method thereof, the film material is prepared by adopting degradable high-barrier polypropylene carbonate and polyvinyl alcohol, the film material is degradable and has good barrier property, but a large amount of water-soluble polymers such as polyvinyl alcohol are adopted, so that the obvious defect of poor hydrolysis resistance exists, and the mechanical property needs to be further improved. Chinese patent CN104830035 discloses a biodegradable composition with barrier property and a preparation method and application thereof, and specifically discloses a biodegradable composition comprising biodegradable polyester and a waterproof agent, wherein the waterproof agent mainly comprises mineral wax with high boiling point, organic matters and the like, the composition can have good waterproof property only by mainly utilizing the characteristics of insensitivity, nondegradation and the like of the components, and the prepared composition or product has certain degradability due to the nondegradability of the components, but can still cause environmental pollution if not completely degraded.

In summary, the conventional barrier buffer air cushion film with barrier property still has the technical problems that the gas barrier property, the mechanical property, the heat sealing property and the like are required to be further improved. In addition, the applicant also finds that the use requirement and the structural characteristic of the completely degradable buffer air cushion film easily cause the problems of bag making, cylinder film adhesion and the like in the preparation process of a thin film due to the use requirement and the structural characteristic of the buffer air cushion film, and the processing performance is influenced. Meanwhile, the degradability of the barrier buffer air cushion film needs to be considered, so that the environment pollution is avoided.

Disclosure of Invention

In order to solve the problem of environmental pollution caused by the traditional buffer air cushion film and simultaneously take into account the attractive appearance of the package and the product performance, the application provides a barrier air cushion film made of a completely degradable novel composite material. It not only has the same good heat sealing performance and barrier property as PE/PA composite membrane, but also can degrade more than 90% of the material into water and carbon dioxide after being placed in soil for 6 months.

Specifically, a first aspect of the present invention provides a completely degradable gas barrier air cushion film excellent in processability, which includes an outer layer, a middle layer and an inner layer; the thickness ratio of the outer layer to the middle layer to the inner layer is 40: (10-20): (35-55); the gas barrier air cushion film is prepared from degradable materials; the preparation raw materials of the outer layer, the middle layer and the inner layer all comprise polymethyl ethylene carbonate; the raw materials for preparing the outer layer also comprise inorganic filler and PBAT, and the content of the inorganic filler accounts for at least 30wt% of the raw materials for preparing the outer layer.

As a preferred embodiment, the inorganic filler comprises calcium carbonate and/or talc; preferably, the calcium carbonate and talc are present in the same amount.

As a preferred technical scheme, the preparation raw materials of the inner layer also comprise PBAT and a filler; the filler content is at most 15wt% of the inner layer preparation raw material.

As a preferred technical solution, the filler comprises fumed silica and talc; preferably, the talc powder is hydrophobic talc powder.

As a preferred technical scheme, the mesh number of the hydrophobic talcum powder is not less than 2000 meshes; preferably, the mesh number of the hydrophobic talcum powder is 2500 meshes.

As a preferable technical scheme, the preparation raw material of the middle layer also comprises polyglycolide; the weight ratio of the polymethyl ethylene carbonate to the polyglycolide is (3-5): 1.

as a preferable technical scheme, the weight average molecular weight of the PBAT is 15-20 ten thousand; preferably, the PBAT and the polymethylethylene carbonate have the same weight average molecular weight.

As a preferred technical scheme, the content of the polymethyl ethylene carbonate in the raw materials for preparing the outer layer and the inner layer is at least 15wt percent respectively.

As a preferred technical scheme, the content of the polymethyl ethylene carbonate in the raw materials for preparing the outer layer and the inner layer is respectively at most 30wt%.

As a preferable technical scheme, the PBAT is a mixture modified by a functional assistant; the functional auxiliary agent comprises an alcohol modifier with the boiling point not lower than 210 ℃.

A second aspect of the present invention provides a method for producing a fully degradable gas barrier air cushion film excellent in processability as described above, comprising the steps of:

(1) Heat-treating the polymethyl ethylene carbonate at 80 ℃ for 2-6 hours;

(2) Respectively adding the preparation raw materials of the outer layer, the middle layer and the inner layer into a high-speed mixer, mixing, adding into a double-screw extruder, adjusting the temperature of the double-screw extruder to 80-190 ℃, and extruding and granulating to obtain a modified material;

(3) And respectively adding the modified materials to a three-layer co-extrusion film blowing machine, adjusting the temperature of the film blowing machine to 130-185 ℃, performing blow molding to form a cylindrical film, slitting, and performing post-treatment to obtain the modified material.

Has the beneficial effects that: the completely degradable gas barrier air cushion film with excellent processing performance adopts completely degradable materials, so that the air cushion film can have a completely degradable function and cannot pollute the environment when being used. Moreover, the air cushion film has excellent gas barrier performance and barrier performance through the optimized design of the three-layer structure, and the barrier performance can reach 60O ₂ /(cm ³ /(m ² D.atm)) below. In addition, the PPC materials are added into the three layers, the problem of interlayer delamination of the multilayer coextrusion can be solved without adding non-degradable materials such as chain extenders, compatilizers and the like, tests show that the outer layer and the inner layer can be well bonded together by adding 20 percent of PPC,effectively avoids the problems of poor interlayer adhesiveness, delamination and the like. And secondly, the heat seal strength, the barrier property and the heat seal property of the buffer air cushion film are effectively improved by regulating and controlling the components, the proportion, the physical and chemical parameters of the components and the like of the three layers of the formula, namely the inner layer, the outer layer and the middle layer. Meanwhile, the problems of size shrinkage, surface wrinkles and the like of a product caused by the fact that raw materials cannot be rapidly cooled and hardened in the preparation process of the air cushion film are unexpectedly and remarkably improved. In addition, the air cushion film provided by the invention has excellent processing performance, the problems of cylinder film adhesion, bag making scalding, dimensional stability and the like caused by temperature resistance difference between the inner layer raw material and the outer layer raw material are effectively avoided, and the production efficiency and the yield of products are greatly improved.

Detailed Description

The technical features of the technical solutions provided by the present invention will be further clearly and completely described below with reference to the specific embodiments, and it should be apparent that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The words "preferred", "preferably", "more preferred", and the like, in the present invention, refer to embodiments of the invention that may provide certain benefits, under certain circumstances. However, other embodiments may be preferred, under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, and is not intended to exclude other embodiments from the scope of the invention.

It should be understood that other than in any operating examples, or where otherwise indicated, all numbers expressing, for example, quantities of ingredients used in the specification and claims are to be understood as being modified in all instances by the term "about".

The melt index measurement described in the present invention was carried out at 190 ℃ under 2.16 kg.

A first aspect of the present invention provides a completely degradable gas barrier air cushion film excellent in processability, which includes an outer layer, a middle layer and an inner layer; the thickness ratio of the outer layer to the middle layer to the inner layer is 40: (10-20): (35-55); the gas barrier air cushion film is prepared from degradable materials; the preparation raw materials of the outer layer, the middle layer and the inner layer all comprise polymethyl ethylene carbonate; the preparation raw materials of the outer layer also comprise inorganic filler and PBAT. The content of the inorganic filler accounts for at least 30wt% of the raw materials for preparing the outer layer.

The applicant finds that the unstable phenomenon such as shaking is easy to occur due to the relatively soft bubble, which causes the problems of delamination, wrinkling and the like between layers, and particularly, when a certain proportion of the PPC material is used in the air cushion film of the present application, the unstable phenomenon between layers is easy to occur due to the slow solidification and molding speed of the PPC material. And the inorganic filler with a certain content is added into the outer layer preparation raw material, so that the rigidity and the stiffness of the outer layer solution are improved, a certain supporting effect is provided for the film bubble, the shaking of the film bubble is avoided, and the adverse problems of folds and the like between the inner layer and the outer layer are avoided. Meanwhile, the applicant unexpectedly discovers that the mucous membrane condition generated in the film blowing process can be effectively improved by adding a certain amount of inorganic filler in the outer layer preparation raw material, and unstable factors caused by the fact that PPC cannot be crystallized are effectively improved. The improvement is particularly remarkable when the inorganic filler content of the outer layer is not less than 30%.

In some preferred embodiments, the inorganic filler is present in the outer layer preparation feedstock in an amount of at least 30wt% of the outer layer preparation feedstock.

In some embodiments, the inorganic filler comprises calcium carbonate and/or talc; preferably, the calcium carbonate and the talcum powder have the same content; more preferably, the calcium carbonate and talc are low mesh (large size) calcium carbonate and talc (e.g., 800 mesh)

The applicant finds that when the content of the inorganic filler in the outer layer is not less than 30%, the yield of products such as buffer bags and the like can be improved to a great extent, and the bag making scalding probability is remarkably reduced, and particularly when the adopted inorganic filler is small in mesh and large in size and particle size, the effect is particularly remarkable. The applicant speculates that it is possible that the heat sealing die in the present application first contacts the outer layer material during heat sealing bag making, then melts the inner layer material by transferring heat through the outer layer to the inner layer material, and bonds the two melted inner layer materials together by applying pressure to achieve heat sealing. Due to the difference between the heat resistance and the heat conductivity of the inner and outer layer raw materials, the outer layer is heated higher, and the inner layer is heated lower, so that the bag making is easy to scald, and the yield of products is influenced. The outer layer material is heated to a higher degree, and the inner layer material is heated to a lower degree, so the heat resistance of the outer layer material is better than that of the inner layer material, therefore, a certain content of inorganic filler is required to be ensured in the outer layer preparation raw material, and the condition that a bag is scalded can be avoided. And when the mesh number of the inorganic filler in the outer layer is smaller, the size is larger, heat can be better transmitted, the heat resistance is better, and the product yield is better improved.

In some embodiments, the starting materials for the preparation of the inner layer further comprise PBAT and fillers; further preferably, the filler is fumed silica. The applicant has found in the course of completing the present invention that when the same content of inorganic filler as that of the outer layer is used in the inner layer, although the occurrence of sticking when the film web passes through the herringbone nipper plate can be prevented, the heat sealability becomes poor, and peeling easily occurs in the heat-sealed area after heat-sealing at 140 ℃. When the meteorological silica is adopted as the inorganic filler of the inner layer, the problem of cylinder film adhesion of the air cushion film can be obviously improved, and the using amount of the inorganic filler can be obviously reduced. However, the amount of fumed silica used is also critical, and when it is used in too small an amount (especially less than 1 wt%), the problem of can film sticking still occurs. Accordingly, in some preferred embodiments of the present invention, the content of the inorganic filler in the inner layer raw material is at least 1wt% of the inner layer raw material.

In some preferred embodiments, the filler further comprises talc; the content of the filler accounts for at most 15wt% of the inner layer preparation raw material; preferably, the content of the filler accounts for 10wt% of the inner layer raw material; further preferably, the talcum powder is hydrophobic talcum powder; further preferably, the talc is a high-mesh (small-size) talc; furthermore, the mesh number of the hydrophobic talcum powder is not less than 2000 meshes; preferably, the mesh number of the hydrophobic talcum powder is 2500 meshes.

The applicant has found that when a certain amount of talc is added while the fumed silica inorganic filler is used in the inner layer, the heat seal strength of the air cushion film can be significantly improved. Probably because the addition of the fumed silica and the talcum powder can improve the cohesive strength of the raw materials and increase the energy required for peeling the film. Further, the applicant has unexpectedly found that the improvement of the heat seal strength and the high-temperature and high-humidity aging strength is particularly remarkable when a high-mesh talc powder is used, and the above effects are particularly remarkable when a hydrophobic high-mesh talc powder is used. Probably because the hydrophobic talcum powder with high mesh number can improve the hydrolysis resistance of the film while enhancing the cohesive strength of the inner layer raw material, so that the film can still keep high heat seal strength in a high-temperature environment.

Applicants have found that by controlling the composition and amount of inorganic filler in the inner and outer layers, which can be up to 35m/min, it can help to improve the production rate of the article (e.g., bag making), especially when the inorganic filler content of the outer and inner layer materials is 30 to 40wt% and 10wt%, respectively. The applicant speculates that the forming speed of the raw material is accelerated mainly because the outer layer has higher filler content and larger size, while the inner layer has less filler, smaller size and better solution flow property. And the outer layer raw material has good heat resistance, avoids the situation that the bag is scalded, and ensures smooth operation in the process of heat-sealing the bag. Meanwhile, the inner layer filler can reduce the influence on the heat seal performance while increasing the foam stability and improving the dimensional stability of the product.

In some embodiments, the outer layer, middle layer, and inner layer have a thickness ratio of 40: (10-20): (35-55); further preferably, the thickness ratio of the outer layer, the middle layer and the inner layer is 40:15:45.

the completely degradable gas barrier air cushion film with excellent processing performance comprises an outer layer, a middle layer and an inner layer, which are all made of degradable materials, so that the prepared air cushion film can be degraded by 100 percent, and the pollution to the environment is avoided. The air cushion film of the invention comprises polymethyl ethylene carbonate in the inner and outer middle layer materials. The polymethyl ethylene carbonate (PPC) is also called polypropylene carbonate, and is a completely degradable environment-friendly material synthesized by taking carbon dioxide and propylene oxide as raw materials. By adding a proper amount of PPC raw materials into the outer layer, the middle layer and the inner layer, the degradability of the buffer air cushion film is improved, and the buffer air cushion film is completely degradable by 100%.

In some embodiments, the raw materials for preparing the middle layer further comprise polyglycolide; the weight ratio of the polymethyl ethylene carbonate to the polyglycolide is (3-5): 1. further preferably, the weight average molecular weight of the polymethyl ethylene carbonate and the weight average molecular weight of the polyglycolide are the same; more preferably, the polyglycolide has a melt index of 5 to 10g/10min.

The middle layer adopts PGA modified PPC. Due to the structural characteristics of the linear aliphatic chain segment of the polyglycolide, the raw materials are easy to be orderly arranged to form a high-crystalline compact stacking structure in the melt extrusion molding process, so that the buffer air cushion film has excellent air barrier performance. The applicant finds that when the filler is added into the middle layer, the closely-packed crystalline structure in the middle layer structure is easily damaged, so that the tightness of the middle layer structure is deteriorated, and the barrier property of the air cushion film is influenced. Moreover, due to the structural characteristics of the aliphatic polyester PPC, the aliphatic polyester PPC also has excellent barrier property and degradation property. Especially, the weight ratio of the polymethyl ethylene carbonate to the polyglycolide is preferably adjusted to (3-5) through adjusting the dosage ratio of the polyglycolide to the PPC in the layer structure of the air cushion film: 1 (preferably 4 ₂ /(cm ³ /(m ² D.atm)) below.

The applicant finds that the cooling forming speed of the PPC raw material is slow in the preparation process of the air cushion film, and the problems of size shrinkage and the like easily occur after the PPC raw material is placed for a period of time after forming. In addition, due to the difference of cohesive energy between the PPC and the PBAT, the size change between the inner layer and the outer layer and the middle layer is inconsistent, so that the surface of the air cushion film is wrinkled, and the appearance, the mechanical property and other characteristics of the product are influenced. After the PGA is compounded with polyglycolide, especially when the ratio of PPC to polyglycolide is in a specific ratio (e.g. 4. The applicant speculates that the side methyl group in the PPC structure influences the ordered arrangement or crystallization of polymer segments, so that the cooling forming speed of the middle layer is slow, and the problems of product size shrinkage, surface wrinkles and the like are caused. After the polyglycolide is compounded with the polyglycolide for use, due to the structural characteristics of the polyglycolide, the polyglycolide can crystallize and promote the sequential arrangement of the induced PPC, so that the cooling forming speed of the middle layer structure can be accelerated, the middle layer structure and the inner and outer layers can be synchronously cured and formed, and the stable size can be kept in the placing process, thereby avoiding the problems. Especially when the adopted polyglycolide has the melt index ranging from 5 to 10g/10min, especially ranging from 6 to 8g/10min, the size stability of the product is more obviously facilitated.

Moreover, the applicant also finds that the characteristics of the PPC and polyglycolide structure cause certain compatibility problem when the regulation and control of the compounding ratio, the physicochemical parameters and the like are not proper, so that the addition of auxiliary agent components such as additional compatilizer and the like is needed to ensure that the components can be fully dispersed and mixed, and the addition of the auxiliary agent can reduce the barrier property and the processing property of the air cushion film. When the weight average molecular weights of the adopted polyglycolide and the PPC are close to or the same with each other, the sufficient dispersion and mixing of the polyglycolide and the PPC can still be ensured on the premise of not adding any other auxiliary agent, the blending modification can be realized through a simple double-screw extruder, and the characteristics of the air cushion film such as dimensional stability, mechanical property, processability and the like are further improved.

In some embodiments, the PBAT has a weight average molecular weight of 15 to 20 ten thousand; preferably, the PBAT and the polymethylethylene carbonate have the same weight average molecular weight. In some preferred embodiments, the PBAT has a melt index of 10 to 15g/10min. In some preferred embodiments, the PBAT is a mixture modified with a functional aid; the functional auxiliary agent comprises an alcohol modifier with the boiling point not lower than 210 ℃. Further, the boiling point of the alcohol modifier is not higher than 260 ℃. More preferably, the alcohol modifier is 1, 4-butanediol. Preferably, the content of the alcohol modifier accounts for 0.5 to 3 weight percent of the total mass of the modified mixture.

When the air cushion film is blown, the film bubble is soft, unstable phenomena such as shaking and the like are easy to occur, so that the problems of delamination, wrinkling and the like occur between layers, and particularly, after a certain proportion of PPC material is adopted in the air cushion film, the PPC material is slow in solidification and forming speed, so that the unstable situation between the layers is easy to occur. The applicant has found that the use of PBAT material in the inner and outer layer of raw material, in a specific ratio to PPC, significantly improves the above processing problems. The applicant speculates that the PBAT structure contains a certain content of aromatic benzene ring structure and is a semi-crystalline polymer, and the crystal structure formed after the PBAT is melted and extruded improves the rigidity of a melt and provides certain stiffness for a film bubble, thereby being beneficial to improving the comprehensive performance of the product. Especially, after a proper amount of inorganic filler is added into the raw materials of the outer layer and the inner layer, and the components, the physical and chemical parameters and the content of the inorganic filler of the outer layer and the inner layer are regulated and controlled, the processing performance of the product is further improved under the synergistic action of the components. The PBAT melt index is regulated and controlled, so that the raw materials of the inner layer and the outer layer are fully melted in a double-screw extruder to form uniform solution, and uniform and stable film bubbles are formed after extrusion and blow molding, so that better processing performance is realized.

Moreover, the PBAT in the invention is a mixture modified by functional additives; the functional auxiliary agent is preferably 1, 4-butanediol. The applicant finds that the solution fluidity of the raw materials of the inner layer and the outer layer of the air cushion film during melt extrusion can be remarkably improved by modifying the PBAT with the alcohol modifier, so that the compatibility between the PBAT and the (inorganic) filler is improved, the filler and the polymer are fully and uniformly dispersed, and the problems of poor mechanical property of a film caused by stress concentration points possibly appearing between the raw materials of the inner layer and the outer layer, low product efficiency caused by poor heat conductivity and the like are avoided. In addition, the applicant finds that because PPC raw materials in the inner layer and the outer layer are not easy to crystallize, mucous membranes are easy to occur in the raw materials during film blowing, and when the cylinder film passes through the herringbone clamping plate pinch roller, the two films are easy to adhere together and cannot be opened, so that the normal production and use of the air cushion film are influenced. And a certain content of filler is added into the outer layer and the inner layer, so that the opening smoothness can be obviously improved, and the unsmooth processing of the film in the preparation process is avoided. Particularly, the smoothness of the film can be obviously improved after the inorganic filler added into the outer layer preparation raw material reaches a certain content.

In some embodiments, the amount of the polymethylethylene carbonate in the starting materials for the outer and inner layers, respectively, is at least 15wt%; further preferably, the content of the polymethyl ethylene carbonate in the preparation raw materials of the outer layer and the inner layer is respectively at most 30wt%; further preferably, the filler content in the outer layer and the inner layer is 20wt%. More preferably, the weight average molecular weights of the polymethyl ethylene carbonate and the polyglycolide are the same and are both 15 to 20 ten thousand.

The applicant finds that the regulation of the weight average molecular weights of the PBAT and the polymethyl ethylene carbonate is beneficial to improving the mixing effect of the PBAT and the polymethyl ethylene carbonate, when the weight average molecular weights of the adopted polymethyl ethylene carbonate and the PBAT are close to or equal to each other, good compatibility can be realized on the premise that components such as a compatilizer are not used, the purpose of fully mixing is achieved, and particularly when the melt indexes of the adopted PBAT and the polymethyl ethylene carbonate are in a specific range, the effect is more remarkable. Further, it is preferable that the content of the polymethylethylene carbonate in the raw materials for the preparation of the outer layer and the inner layer is 20wt%. The applicant finds that the problem of interlayer delamination of the multilayer co-extrusion layers can be solved by adding a proper amount of polymethyl ethylene carbonate into the three layers on the premise of not additionally adding non-degradable materials such as chain extenders, compatilizers and the like, however, the content of the polymethyl ethylene carbonate cannot be too small, otherwise, the effect is not obvious, and a large number of experimental summaries and analyses find that when the content of the polymethyl ethylene carbonate in each layer is lower than 10wt%, the effect is not obvious, particularly, the heat sealing effect at low temperature is poor, and delamination is easy to occur. At the same time, applicants have also found that too high a content of polymethylethylene carbonate can also affect the proper processing of the air cushion film and the properties of the resulting article of manufacture. When the content is more than 25wt%, particularly more than 30wt%, the resulting air cushion film is liable to cause adhesion between the inner and outer surfaces thereof. Moreover, the PBAT and the PGA in the inner and the outer layers are blended and modified. The applicant also found that the shelf life of the product can be significantly improved while improving the barrier property, processability, etc. of the air cushion film by using a certain amount of polymethyl ethylene carbonate in each layer of the air cushion film, and the shelf life of the product of the invention is prolonged by more than 6 times compared with the product using only PBAT.

(1) Heat-treating the polymethyl ethylene carbonate at 80 ℃ for 2-6 hours;

Furthermore, the modified material prepared in the step (2) has different processes according to different preparation raw materials of the inner and outer middle layers.

Preferably, the temperature of the twin-screw extruder in the preparation process of the outer layer modified material is set as follows:

feeding section

Heating section

Plasticizing section

Compression stage

Discharge port

Cooling method

Outer layer preparation raw material

80℃

140

150

5m water tank

feeding section

Heating section

Plasticizing section

Compression stage

Discharge port

Cooling method

Raw material for preparing middle layer

90℃

180

185

190

10m water tank

Preferably, the temperature of the twin-screw extruder in the preparation process of the inner layer modified material is set as follows:

formulation of

Feeding section

Heating section

Plasticizing section

Compression section

Discharge port

Cooling method

Inner layer preparation raw material

80℃

140

150

5m water tank

Further, in the step (3), the temperature parameters of the film blowing machine are different according to different modified materials of the inner layer and the outer layer.

Preferably, the temperature parameters of the film blowing extruder of the outer layer modified material are set as follows:

	feeding section	Heating section	Plasticizing section	Compression section	Die temperature
						Outer layer modified material	130℃	140	150	150	155

Preferably, the temperature parameters of the film blowing extruder of the middle layer modifier are set as follows:

	feeding section	Heating section	Plasticizing section	Compression section	Die temperature
						Middle layer modified material	130℃	180	185	180	180

Preferably, the temperature parameters of the film blowing extruder of the inner layer modified material are set as follows:

formulation(s)	Feeding section	Heating section	Plasticizing section	Compression stage	Die temperature
						Inner layer modified material	130℃	140	150	150	150

The thickness range of the blown film is more than or equal to 3.8 mu m. And (3) cutting the cylindrical film into an upper piece of the surface film and a lower piece of the surface film at the film rolling position, rolling, and marking the inner layer and the outer layer. Bag making: the inner layer is heat sealed by the upper and lower film inner layers, and various buffer air cushion products, such as air columns, calabash balls, gang rows and the like, are produced through different structures and drawing discs of the heat sealing die.

The present invention will be specifically described below by way of examples. It is to be noted that the following examples are given solely for the purpose of illustration and are not to be construed as limitations on the scope of the invention, as many insubstantial modifications and variations of the invention described above will now occur to those skilled in the art.

Examples

Example 1: this example provides a fully degradable gas barrier air cushion film with excellent processability comprising an outer layer, a middle layer and an inner layer; the thickness ratio of the outer layer to the middle layer to the inner layer is 40:15:45, a first step of; the gas barrier air cushion film is prepared from degradable materials; the preparation raw materials of the outer layer, the middle layer and the inner layer all comprise polymethyl ethylene carbonate.

The raw materials for preparing the outer layer comprise, by weight, 50 parts of PBAT,20 parts of PPC,15 parts of 800-mesh talcum powder and 15 parts of 800-mesh unactivated common calcium carbonate; the preparation raw material of the middle layer comprises 80 parts of PPC and 20 parts of polyglycolide in parts by weight; the inner layer is prepared from raw materials, by weight, 70 parts of PBAT,20 parts of PPC,2 parts of fumed silica and 8 parts of 2500-mesh hydrophobic talcum powder.

The weight average molecular weight of the PBAT is about 18 ten thousand, the PBAT is a component modified by 1, 4-butanediol, wherein the content of the 1, 4-butanediol is 1.8wt%, and the melt index of the modified PBAT is about 12g/10min; said PPC having a weight average molecular weight of about 18 million and a melt index of about 2.5g/10min; the polyglycolide has a weight average molecular weight of about 18 ten thousand and a melt index of about 7g/10min.

The preparation method of the completely degradable gas barrier air cushion film comprises the following steps:

(1) Heat-treating the polymethyl ethylene carbonate in the inner and outer middle layers at 80 ℃ for 4 hours;

(2) Respectively adding the preparation raw materials of the outer layer, the middle layer and the inner layer into a high-speed mixer, mixing, adding into a double-screw extruder, adjusting the temperature of the double-screw extruder, extruding and granulating, and drying (drying for 2 hours at 80 ℃) the obtained granules to obtain a modified material; the preparation process parameters of the inner and outer middle layer modified materials are as follows:

/	feeding section	Heating section	Plasticizing section	Compression section	Discharge port	Cooling method
							Outer layer preparation raw material	80℃	140	150	150	150	5m water tank
Raw material for preparing middle layer	90℃	180	185	190	190	10m water tank
							Inner layer preparation raw material	80℃	140	150	150	150	5m water tank

(3) And respectively adding the modified materials to a three-layer co-extrusion film blowing machine, and adjusting the temperature of the film blowing machine to perform blow molding to form a cylindrical film. And (3) cutting the cylindrical film into an upper piece of surface film and a lower piece of surface film at the film rolling position, rolling, and labeling the inner layer and the outer layer to obtain the finished product. The subsequent steps can be realized by bag making: and carrying out heat sealing on the inner layers of the upper and lower rolls of films, and producing the cushion air cushion product through a heat sealing die.

Example 2: the present embodiment provides a completely degradable gas barrier air cushion film excellent in processability, which includes an outer layer, a middle layer and an inner layer; the thickness ratio of the outer layer to the middle layer to the inner layer is 40:15:45, a first step of; the gas barrier air cushion film is prepared from degradable materials; the preparation raw materials of the outer layer, the middle layer and the inner layer all comprise polymethyl ethylene carbonate.

The raw materials for preparing the outer layer comprise, by weight, 50 parts of PBAT,20 parts of PPC,5 parts of 800-mesh talcum powder and 5 parts of 800-mesh unactivated common calcium carbonate; the preparation raw material of the middle layer comprises 80 parts of PPC and 20 parts of polyglycolide in parts by weight; the inner layer is prepared from raw materials, by weight, 70 parts of PBAT,20 parts of PPC,2 parts of fumed silica and 8 parts of 2500-mesh hydrophobic talcum powder.

The PBAT has the weight average molecular weight of about 18 ten thousand, and is a component modified by 1, 4-butanediol, wherein the content of the 1, 4-butanediol is 1.8wt%, and the modified PBAT has the melt index of about 12g/10min; said PPC having a weight average molecular weight of about 18 million and a melt index of about 2.5g/10min; the polyglycolide has a weight average molecular weight of about 18 ten thousand and a melt index of about 7g/10min.

Example 3: the present embodiment provides a completely degradable gas barrier air cushion film excellent in processability, which includes an outer layer, a middle layer and an inner layer; the thickness ratio of the outer layer to the middle layer to the inner layer is 40:15:45, a first step of; the gas barrier air cushion film is prepared from degradable materials; the preparation raw materials of the outer layer, the middle layer and the inner layer all comprise polymethyl ethylene carbonate.

The raw materials for preparing the outer layer comprise, by weight, 50 parts of PBAT,20 parts of PPC,10 parts of 800-mesh talcum powder and 10 parts of 800-mesh unactivated common calcium carbonate; the preparation raw material of the middle layer comprises 80 parts of PPC and 20 parts of polyglycolide in parts by weight; the inner layer is prepared from raw materials, by weight, 70 parts of PBAT,20 parts of PPC,2 parts of fumed silica and 8 parts of 2500-mesh hydrophobic talcum powder.

Example 4: this example provides a fully degradable gas barrier air cushion film with excellent processability comprising an outer layer, a middle layer and an inner layer; the thickness ratio of the outer layer to the middle layer to the inner layer is 40:15:45, a first step of; the gas barrier air cushion film is prepared from degradable materials; the preparation raw materials of the outer layer, the middle layer and the inner layer all comprise polymethyl ethylene carbonate.

The raw materials for preparing the outer layer comprise, by weight, 50 parts of PBAT,20 parts of PPC,20 parts of 800-mesh talcum powder and 20 parts of 800-mesh unactivated common calcium carbonate; the preparation raw material of the middle layer comprises 80 parts of PPC and 20 parts of polyglycolide in parts by weight; the preparation raw materials of the inner layer comprise, by weight, 70 parts of PBAT,20 parts of PPC,2 parts of fumed silica and 8 parts of 2500-mesh hydrophobic talcum powder.

Example 5: the present embodiment provides a completely degradable gas barrier air cushion film excellent in processability, which includes an outer layer, a middle layer and an inner layer; the thickness ratio of the outer layer to the middle layer to the inner layer is 40:15:45, a first step of; the gas barrier air cushion film is prepared from degradable materials; the preparation raw materials of the outer layer, the middle layer and the inner layer all comprise polymethyl ethylene carbonate.

The preparation raw materials of the outer layer comprise, by weight, 50 parts of PBAT,20 parts of PPC,25 parts of 800-mesh talcum powder and 25 parts of 800-mesh unactivated common calcium carbonate; the preparation raw material of the middle layer comprises 80 parts of PPC and 20 parts of polyglycolide in parts by weight; the preparation raw materials of the inner layer comprise, by weight, 70 parts of PBAT,20 parts of PPC,2 parts of fumed silica and 8 parts of 2500-mesh hydrophobic talcum powder.

The applicant observed the adhesion of the film in the production process of the air cushion film in the above examples, and found that when 800 mesh calcium carbonate and 800 mesh talc were used as the filler in the outer layer, the film surface was remarkably adhered at a filler content of less than 30wt%, and the specific results are shown in the following table.

TABLE 1 Performance test Table

	Example 1	Example 2	Example 3	Example 4	Example 5
						Cylinder film bonding	Whether or not	Is that	Is that	Whether or not	Whether or not

Example 6: the present embodiment provides a completely degradable gas barrier air cushion film excellent in processability, which includes an outer layer, a middle layer and an inner layer; the thickness ratio of the outer layer to the middle layer to the inner layer is 40:15:45, a first step of; the gas barrier air cushion film is prepared from degradable materials; the preparation raw materials of the outer layer, the middle layer and the inner layer all comprise polymethyl ethylene carbonate.

The raw materials for preparing the outer layer comprise, by weight, 50 parts of PBAT,20 parts of PPC,15 parts of 800-mesh talcum powder and 15 parts of 800-mesh unactivated common calcium carbonate; the preparation raw material of the middle layer comprises 80 parts of PPC and 20 parts of polyglycolide in parts by weight; the inner layer is prepared from raw materials, by weight, 70 parts of PBAT,20 parts of PPC,5 parts of 800-mesh talcum powder and 5 parts of 800-mesh unactivated common calcium carbonate.

Example 7: the present embodiment provides a completely degradable gas barrier air cushion film excellent in processability, which includes an outer layer, a middle layer and an inner layer; the thickness ratio of the outer layer to the middle layer to the inner layer is 40:15:45, a first step of; the gas barrier air cushion film is prepared from degradable materials; the preparation raw materials of the outer layer, the middle layer and the inner layer all comprise polymethyl ethylene carbonate.

The raw materials for preparing the outer layer comprise, by weight, 50 parts of PBAT,20 parts of PPC,15 parts of 800-mesh talcum powder and 15 parts of 800-mesh unactivated common calcium carbonate; the preparation raw material of the middle layer comprises 80 parts of PPC and 20 parts of polyglycolide in parts by weight; the preparation raw materials of the inner layer comprise, by weight, 70 parts of PBAT,20 parts of PPC,10 parts of 800-mesh talcum powder and 10 parts of 800-mesh unactivated common calcium carbonate.

Example 8: the present embodiment provides a completely degradable gas barrier air cushion film excellent in processability, which includes an outer layer, a middle layer and an inner layer; the thickness ratio of the outer layer to the middle layer to the inner layer is 40:15:45, a first step of; the gas barrier air cushion film is prepared from degradable materials; the preparation raw materials of the outer layer, the middle layer and the inner layer all comprise polymethyl ethylene carbonate.

The raw materials for preparing the outer layer comprise, by weight, 50 parts of PBAT,20 parts of PPC,15 parts of 800-mesh talcum powder and 15 parts of 800-mesh unactivated common calcium carbonate; the preparation raw material of the middle layer comprises 80 parts of PPC and 20 parts of polyglycolide in parts by weight; the preparation raw materials of the inner layer comprise, by weight, 70 parts of PBAT,20 parts of PPC,15 parts of 800-mesh talcum powder and 15 parts of 800-mesh unactivated common calcium carbonate.

Example 9: this example provides a fully degradable gas barrier air cushion film with excellent processability comprising an outer layer, a middle layer and an inner layer; the thickness ratio of the outer layer to the middle layer to the inner layer is 40:15:45, a first step of; the gas barrier air cushion film is prepared from degradable materials; the preparation raw materials of the outer layer, the middle layer and the inner layer all comprise polymethyl ethylene carbonate.

The raw materials for preparing the outer layer comprise, by weight, 50 parts of PBAT,20 parts of PPC,15 parts of 800-mesh talcum powder and 15 parts of 800-mesh unactivated common calcium carbonate; the preparation raw material of the middle layer comprises 80 parts of PPC and 20 parts of polyglycolide in parts by weight; the inner layer is prepared from raw materials, by weight, 70 parts of PBAT,20 parts of PPC,20 parts of 800-mesh talcum powder and 20 parts of 800-mesh unactivated common calcium carbonate.

Example 10: the present embodiment provides a completely degradable gas barrier air cushion film excellent in processability, which includes an outer layer, a middle layer and an inner layer; the thickness ratio of the outer layer to the middle layer to the inner layer is 40:15:45, a first step of; the gas barrier air cushion film is prepared from degradable materials; the preparation raw materials of the outer layer, the middle layer and the inner layer all comprise polymethyl ethylene carbonate.

The raw materials for preparing the outer layer comprise, by weight, 50 parts of PBAT,20 parts of PPC,15 parts of 800-mesh talcum powder and 15 parts of 800-mesh unactivated common calcium carbonate; the preparation raw material of the middle layer comprises 80 parts of PPC and 20 parts of polyglycolide in parts by weight; the inner layer is prepared from raw materials, by weight, 70 parts of PBAT,20 parts of PPC,25 parts of 800-mesh talcum powder and 25 parts of 800-mesh unactivated common calcium carbonate.

The applicant observed the adhesion of the drum film during the preparation of the air cushion film in the above examples, and found that when 800 mesh calcium carbonate and 800 mesh talc were used as the filler of the outer layer, the film surface was remarkably adhered at a filler content of less than 30wt%, and the specific results are shown in table 2 below.

TABLE 2

Example 1

Example 6

Example 7

Example 8

Example 9

Example 10

Cylinder film bonding

Whether or not

Is that

Whether or not

Heat sealing at 140 ℃

Qualified

Fail to be qualified

The heat sealability was judged by the criterion that the heat-sealed region was peeled off in the heat seal test, and it was found through the above experiment that the heat sealability of the inner layer was deteriorated when the filler addition amount exceeded 20%.

Example 11: this example provides a fully degradable gas barrier air cushion film with excellent processability comprising an outer layer, a middle layer and an inner layer; the thickness ratio of the outer layer to the middle layer to the inner layer is 40:15:45, a first step of; the gas barrier air cushion film is prepared from degradable materials; the preparation raw materials of the outer layer, the middle layer and the inner layer all comprise polymethyl ethylene carbonate.

The raw materials for preparing the outer layer comprise, by weight, 50 parts of PBAT,20 parts of PPC,15 parts of 800-mesh talcum powder and 15 parts of 800-mesh unactivated common calcium carbonate; the preparation raw material of the middle layer comprises 80 parts of PPC and 20 parts of polyglycolide in parts by weight; the preparation raw material of the inner layer comprises, by weight, 70 parts of PBAT,20 parts of PPC and 0.5 part of fumed silica.

Example 12: the present embodiment provides a completely degradable gas barrier air cushion film excellent in processability, which includes an outer layer, a middle layer and an inner layer; the thickness ratio of the outer layer to the middle layer to the inner layer is 40:15:45, a first step of; the gas barrier air cushion film is prepared from degradable materials; the preparation raw materials of the outer layer, the middle layer and the inner layer all comprise polymethyl ethylene carbonate.

The raw materials for preparing the outer layer comprise, by weight, 50 parts of PBAT,20 parts of PPC,15 parts of 800-mesh talcum powder and 15 parts of 800-mesh unactivated common calcium carbonate; the preparation raw material of the middle layer comprises 80 parts of PPC and 20 parts of polyglycolide in parts by weight; the raw materials for preparing the inner layer comprise, by weight, 70 parts of PBAT,20 parts of PPC and 1 part of fumed silica.

Example 13: the present embodiment provides a completely degradable gas barrier air cushion film excellent in processability, which includes an outer layer, a middle layer and an inner layer; the thickness ratio of the outer layer to the middle layer to the inner layer is 40:15:45, a first step of; the gas barrier air cushion film is prepared from degradable materials; the preparation raw materials of the outer layer, the middle layer and the inner layer all comprise polymethyl ethylene carbonate.

The raw materials for preparing the outer layer comprise, by weight, 50 parts of PBAT,20 parts of PPC,15 parts of 800-mesh talcum powder and 15 parts of 800-mesh unactivated common calcium carbonate; the preparation raw material of the middle layer comprises 80 parts of PPC and 20 parts of polyglycolide in parts by weight; the raw materials for preparing the inner layer comprise, by weight, 70 parts of PBAT,20 parts of PPC and 1.5 parts of fumed silica.

Example 14: the present embodiment provides a completely degradable gas barrier air cushion film excellent in processability, which includes an outer layer, a middle layer and an inner layer; the thickness ratio of the outer layer to the middle layer to the inner layer is 40:15:45, a first step of; the gas barrier air cushion film is prepared from degradable materials; the preparation raw materials of the outer layer, the middle layer and the inner layer all comprise polymethyl ethylene carbonate.

The raw materials for preparing the outer layer comprise, by weight, 50 parts of PBAT,20 parts of PPC,15 parts of 800-mesh talcum powder and 15 parts of 800-mesh unactivated common calcium carbonate; the preparation raw material of the middle layer comprises 80 parts of PPC and 20 parts of polyglycolide in parts by weight; the raw materials for preparing the inner layer comprise, by weight, 70 parts of PBAT,20 parts of PPC and 2 parts of fumed silica.

Example 15: the present embodiment provides a completely degradable gas barrier air cushion film excellent in processability, which includes an outer layer, a middle layer and an inner layer; the thickness ratio of the outer layer to the middle layer to the inner layer is 40:15:45, a first step of; the gas barrier air cushion film is prepared from degradable materials; the preparation raw materials of the outer layer, the middle layer and the inner layer all comprise polymethyl ethylene carbonate.

The raw materials for preparing the outer layer comprise, by weight, 50 parts of PBAT,20 parts of PPC,15 parts of 800-mesh talcum powder and 15 parts of 800-mesh unactivated common calcium carbonate; the preparation raw material of the middle layer comprises 80 parts of PPC and 20 parts of polyglycolide in parts by weight; the preparation raw material of the inner layer comprises, by weight, 70 parts of PBAT,20 parts of PPC and 3 parts of fumed silica.

The applicant observed the adhesion of the film in the process of manufacturing the air-cushion film in the above examples, and found that when 800 mesh calcium carbonate and 800 mesh talc were used as the filler in the outer layer, the film surface was remarkably adhered at a filler content of less than 30wt%, and the specific results are shown in table 3 below.

TABLE 3 results of Performance testing

Example 1

Example 11

Example 12

Example 13

Example 14

Example 15

Cylinder film bonding

Whether or not

Is that

Whether or not

Heat sealing at 140 ℃

Qualified

The experiment shows that the film surface can not be bonded after the addition amount of the fumed silica filler exceeds 1.5 percent.

Example 16: this example provides a fully degradable gas barrier air cushion film with excellent processability comprising an outer layer, a middle layer and an inner layer; the thickness ratio of the outer layer to the middle layer to the inner layer is 40:15:45, a first step of; the gas barrier air cushion film is prepared from degradable materials; the preparation raw materials of the outer layer, the middle layer and the inner layer all comprise polymethyl ethylene carbonate.

The raw materials for preparing the outer layer comprise, by weight, 50 parts of PBAT,20 parts of PPC,15 parts of 800-mesh talcum powder and 15 parts of 800-mesh unactivated common calcium carbonate; the preparation raw material of the middle layer comprises 80 parts of PPC and 20 parts of polyglycolide in parts by weight; the preparation raw materials of the inner layer comprise, by weight, 70 parts of PBAT,20 parts of PPC,2 parts of meteorological silica and 8 parts of 800-mesh common talcum powder.

Example 17: the present embodiment provides a completely degradable gas barrier air cushion film excellent in processability, which includes an outer layer, a middle layer and an inner layer; the thickness ratio of the outer layer to the middle layer to the inner layer is 40:15:45, a first step of; the gas barrier air cushion film is prepared from degradable materials; the preparation raw materials of the outer layer, the middle layer and the inner layer all comprise polymethyl ethylene carbonate.

The raw materials for preparing the outer layer comprise, by weight, 50 parts of PBAT,20 parts of PPC,15 parts of 800-mesh talcum powder and 15 parts of 800-mesh unactivated common calcium carbonate; the preparation raw material of the middle layer comprises 80 parts of PPC and 20 parts of polyglycolide in parts by weight; the preparation raw materials of the inner layer comprise, by weight, 70 parts of PBAT,20 parts of PPC,2 parts of fumed silica and 8 parts of 800-mesh hydrophobic talcum powder.

Example 18: the present embodiment provides a completely degradable gas barrier air cushion film excellent in processability, which includes an outer layer, a middle layer and an inner layer; the thickness ratio of the outer layer to the middle layer to the inner layer is 40:15:45, a first step of; the gas barrier air cushion film is prepared from degradable materials; the preparation raw materials of the outer layer, the middle layer and the inner layer all comprise polymethyl ethylene carbonate.

The raw materials for preparing the outer layer comprise, by weight, 50 parts of PBAT,20 parts of PPC,15 parts of 800-mesh talcum powder and 15 parts of 800-mesh unactivated common calcium carbonate; the preparation raw material of the middle layer comprises 80 parts of PPC and 20 parts of polyglycolide in parts by weight; the inner layer is prepared from raw materials, by weight, 70 parts of PBAT,20 parts of PPC,2 parts of fumed silica and 8 parts of 2500-mesh common talcum powder.

The applicant carried out a 140 degree centigrade heat seal test, a heat seal strength test, and a heat seal strength (aged heat seal strength) test after 48 hours storage at 60 degrees centigrade and 100% humidity on the samples in the above examples, and the results are shown in the following Table 4.

Table 4 results of performance testing

The experiments show that the high-number talcum powder can improve the strength of the film, and the hydrophobic filler can improve the hydrolysis resistance of the film in a high-temperature and high-humidity environment.

Example 19: the present embodiment provides a completely degradable gas barrier air cushion film excellent in processability, which includes an outer layer, a middle layer and an inner layer; the thickness ratio of the outer layer to the middle layer to the inner layer is 40:15:45, a first step of; the gas barrier air cushion film is prepared from degradable materials; the preparation raw materials of the outer layer, the middle layer and the inner layer all comprise polymethyl ethylene carbonate.

The raw materials for preparing the outer layer comprise, by weight, 50 parts of PBAT,20 parts of PPC,5 parts of 800-mesh talcum powder and 5 parts of 800-mesh unactivated common calcium carbonate; the preparation raw material of the middle layer comprises 80 parts of PPC and 20 parts of polyglycolide in parts by weight; the preparation raw materials of the inner layer comprise, by weight, 70 parts of PBAT,20 parts of PPC, 4 parts of fumed silica and 16 parts of 2500-mesh hydrophobic talcum powder.

Applicants conducted a production rate test for the air cushion film in the above-described embodiments, with the test results shown in table 5 below.

TABLE 5 results of Performance test

	Example 1	Example 2	Example 3	Example 4	Example 19
						Production speed	35m/min	15m/min	25m/min	35m/min	Iron and break

From the experimental results, the more the outer layer of filler, the less the inner layer of filler, the larger the heat-resistant temperature difference between the inner layer and the outer layer, and the higher the processing efficiency of the film bag making.

Example 20: the present embodiment provides a completely degradable gas barrier air cushion film excellent in processability, which includes an outer layer, a middle layer and an inner layer; the thickness ratio of the outer layer to the middle layer to the inner layer is 40:15:45, a first step of; the gas barrier air cushion film is prepared from degradable materials; the preparation raw materials of the outer layer, the middle layer and the inner layer all comprise polymethyl ethylene carbonate.

The preparation raw material of the outer layer comprises, by weight, 70 parts of PBAT and 30 parts of talcum powder; the preparation raw material of the middle layer comprises 80 parts of PPC and 20 parts of polyglycolide in parts by weight; the preparation raw material of the inner layer comprises, by weight, 90 parts of PBAT,2 parts of fumed silica and 8 parts of 2500-mesh hydrophobic talcum powder.

Example 21: this example provides a fully degradable gas barrier air cushion film with excellent processability comprising an outer layer, a middle layer and an inner layer; the thickness ratio of the outer layer to the middle layer to the inner layer is 40:15:45, a first step of; the gas barrier air cushion film is prepared from degradable materials; the preparation raw materials of the outer layer, the middle layer and the inner layer all comprise polymethyl ethylene carbonate.

The PBAT has a weight average molecular weight of about 18 ten thousand and a melt index of about 4g/10min; (ii) a Said PPC having a weight average molecular weight of about 18 million and a melt index of about 2.5g/10min; the polyglycolide has a weight average molecular weight of about 18 ten thousand and a melt index of about 7g/10min.

Example 22: the present embodiment provides a completely degradable gas barrier air cushion film excellent in processability, which includes an outer layer, a middle layer and an inner layer; the thickness ratio of the outer layer to the middle layer to the inner layer is 40:15:45, a first step of; the gas barrier air cushion film is prepared from degradable materials; the preparation raw materials of the outer layer, the middle layer and the inner layer all comprise polymethyl ethylene carbonate.

The preparation raw material of the outer layer comprises, by weight, 70 parts of PBAT and 30 parts of talcum powder; the preparation raw material of the middle layer comprises 80 parts of PPC and 20 parts of polyglycolide in parts by weight; the preparation raw materials of the inner layer comprise, by weight, 90 parts of PBAT,2 parts of fumed silica and 8 parts of 2500-mesh hydrophobic talcum powder.

The weight average molecular weight of the PBAT is about 10 ten thousand, the PBAT is a component modified by 1, 4-butanediol, wherein the content of the 1, 4-butanediol is 1.8wt%, and the melt index of the modified PBAT is about 20g/10min; said PPC having a weight average molecular weight of about 18 million and a melt index of about 2.5g/10min; the polyglycolide has a weight average molecular weight of about 12 ten thousand and a melt index of about 7g/10min.

The applicant conducted an oxygen barrier performance test on the air cushion film in the above embodiment; a 5 × 5cm sample of the air cushion film in the above example was cut, and the sample was stored at 30 degrees centigrade and 65% humidity for 24 hours to measure the dimensional change, and the dimensional shrinkage was 1 grade when the dimensional shrinkage was less than 1%, 2 grades (including 3%) when the dimensional shrinkage was 1 to 3%, 3% to 5% (including 5%) when the dimensional shrinkage was 3 grades, and 4 grades when the dimensional shrinkage was 5% or more. The processing performance is as follows: and recording the membrane breaking times per month in the preparation process of the air cushion membrane, wherein the average membrane breaking time per month is 1 grade when the membrane breaking time is not higher than 1 time, 2 grades when 1-4 times (including 3 times) are included, and 3 grades when the membrane breaking time exceeds 4 times. The results are shown in Table 6 below

Table 6 performance testing meter

	Oxygen barrier Property (cm) ³ /(m ² .d.atm)	Dimensional shrinkage Properties	Machining performance of
				Example 1	42	Level 1	Level 1
Example 2	64	Level 1	Grade 3
				Example 3	70	Stage 2	Stage 2
Example 7	54	Stage 2	Grade 3
				Example 8	/	/	Stage 2
Example 9	/	/	Stage 2
				Example 10	/	/	Stage 2

From the above experimental results, it can be seen that the completely degradable gas barrier air cushion film with excellent processability in the present invention adopts a completely degradable material, so that the air cushion film can have a completely degradable function, and the use thereof does not cause environmental pollution. Moreover, the air cushion film has excellent gas barrier performance and barrier performance through the optimized design of the three-layer structure, and the barrier performance can reach 60O ₂ /(cm ³ /(m ² D.atm)) below. In addition, the PPC materials are added into the three layers, the problem of interlayer delamination of the multilayer coextrusion layer can be solved without adding non-degradable materials such as chain extenders, compatilizers and the like, tests show that the PPC materials added into the outer layer and the inner layer in an amount of 20% can be well bonded with the middle layer, and the problems of poor interlayer adhesiveness, delamination and the like are effectively avoided. And secondly, the heat seal strength, the barrier property and the heat seal property of the buffer air cushion film are effectively improved by regulating and controlling the components, the proportion, the physical and chemical parameters of the components and the like of the three layers of the formula, namely the inner layer, the outer layer and the middle layer. Meanwhile, the problems of size shrinkage, surface wrinkles and the like of a product during placement due to the fact that raw materials cannot be rapidly cooled and hardened in the preparation process of the air cushion film are also unexpectedly and remarkably improved. In addition, the air cushion film provided by the invention has excellent processing performance, the problems of barrel film adhesion, bag making scalding, dimensional stability and the like caused by temperature resistance difference between the inner layer raw material and the outer layer raw material are effectively avoided, and the production efficiency and the yield of products are greatly improved.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention in other forms, and any person skilled in the art may modify or change the technical content of the above disclosure into equivalent embodiments with equivalent changes, but all those simple modifications, equivalent changes and modifications made to the above embodiments according to the technical spirit of the present invention still belong to the protection scope of the present invention.

Claims

1. A completely degradable gas barrier air cushion film excellent in processability, characterized by comprising an outer layer, a middle layer and an inner layer; the thickness ratio of the outer layer to the middle layer to the inner layer is 40: (10-20): (35-55); the preparation raw materials of the outer layer comprise, by weight, 50 parts of PBAT,20 parts of PPC,15 parts of 800-mesh talcum powder and 15 parts of 800-mesh calcium carbonate; the preparation raw material of the middle layer comprises 80 parts of PPC and 20 parts of polyglycolide in parts by weight; the preparation raw materials of the inner layer comprise, by weight, 70 parts of PBAT,20 parts of PPC,2 parts of fumed silica and 8 parts of 2500-mesh hydrophobic talcum powder; the weight average molecular weight of the PBAT is 18 ten thousand, the PBAT is a component modified by 1, 4-butanediol, wherein the content of the 1.4-butanediol is 1.8wt%, and the melt index of the modified PBAT is 12g/10min; the weight average molecular weight of the PPC is 18 ten thousand, and the melt index is 2.5g/10min; the weight average molecular weight of the polyglycolide is 18 ten thousand, and the melt index is 7g/10min.

2. The method for preparing a fully degradable gas barrier air cushion film with excellent processability as claimed in claim 1, which comprises the steps of:

(1) Heat-treating the PPC at 80 ℃ for 2-6 hours;