CN116731488A - Biodegradable bubble film - Google Patents

Abstract

The invention discloses a biodegradable bubble film. In terms of parts by mass, its raw material composition is: 5-20 parts of modified PPC, 60-90 parts of PBAT, 5-20 parts of PLA, 0.1-5 parts of initiator, Branching agent A 0.1-5.0 parts, branching agent B 0.1-5.0 parts, antioxidant 0.2-1 part and slip agent 0.1-1 part. The present invention combines flexible PBAT and rigid PLA to prepare a blend with good flexibility. PPC is a carbon dioxide-based biodegradable plastic with good compatibility with PBAT and PLA, and PPC has good barrier properties. , introducing PPC into the PBAT/PLA blend can improve the mechanical properties and air retention of the bubble film.

Description

A biodegradable bubble film

Technical field

The invention belongs to the technical field of polymer materials, and specifically relates to a biodegradable bubble film and a preparation method thereof.

Background technique

Bubble film is usually made of polyethylene as the main raw material, with the addition of whitening agent, opening agent and other auxiliary materials, and is extruded at high temperature to form bubbles. It has the characteristics of light texture, good transparency, sound insulation, cushioning, etc. It plays the functions of moisture-proof, buffering and heat preservation for the product. It is widely used in shock-resistant buffer packaging of electronics, instruments, ceramics, handicrafts, household appliances, bicycles, kitchens, furniture and lacquer products, glass products and precision instruments. Bubble film is an important packaging material with a wide range of uses. It is mostly disposed of as domestic waste, making it difficult to recycle on a large scale and easily causing serious environmental pollution problems.

The application of biodegradable materials is the first choice material to solve environmental pollution problems. However, there is currently little research on the development and application of degradable bubble films. In the prior art, the invention patent with application number 201610949553.0 discloses a biodegradable bubble film and its preparation process. In terms of parts by mass, the biodegradable bubble film includes components: 10-20 parts of PLA, 70- 80 parts of PBAT, 0.03-0.07 parts of antioxidant, 2-3 parts of biocompatibility agent, 3-5 parts of heat sealing aid, 1-2 parts of toughening agent, 5-9 parts of inorganic filler. This biodegradable bubble film is degradable and has excellent mechanical properties. However, because the compatibility and melting temperature of PLA and PBAT are quite different, it is unstable during extrusion processing and the molten material is easily extruded during heat sealing. , causing shrinkage and wrinkling of the heat sealing parts, reducing the heat sealing strength and impact resistance.

Application No. 202111669443.6 discloses a carbon dioxide-based degradable shock-proof bubble film and its preparation method, which is prepared by mixing 50-70 parts of PPC and 30-50 parts of PBAT. The melt strength of the raw material components in this invention is low, the melt viscosity is high, the PPC processing stability is poor, and the product performance is poor.

Application number 202110358422.6 provides a method for preparing bubble films of starch and PBAT composite materials, including the following components: 60-90 parts of PBAT, 5-20 parts of starch, 5-20 parts of montmorillonite, 0.1-1 part of lubricant, Compatibilizer 0.1-3 parts and stabilizer 0.01-0.1 parts. In this invention, starch is added to PBAT as a filler, and starch is added as a bio-based raw material. Although it can speed up the degradation cycle, the starch particle size is large, the particle size distribution is uneven, and the particle surface is hydrophilic hydroxyl group, which is incompatible with PBAT. , often leading to a decrease in the performance of blends and their products. These shortcomings limit the application of biodegradable resin in the field of bubble bags.

Contents of the invention

In view of the shortcomings of the existing technology, the present invention provides a biodegradable bubble film to solve many problems of poor performance of degradable bubble film materials and their products at this stage.

In order to achieve the above objects, the present invention adopts the following technical solutions:

A biodegradable bubble film, in terms of parts by mass, includes the following components: 5-20 parts of modified PPC, 60-90 parts of PBAT, 5-20 parts of PLA, 0.1-5 parts of initiator, branching agent A 0.1-5.0 parts, branching agent B 0.1-5.0 parts, antioxidant 0.2-1 part and slip agent 0.1-1 part.

Further, the modified PPC is made by placing PPC and end-capping agent in a high-speed mixer at a mass ratio of 100:0.5 and mixing at high speed, then adding the mixture to a twin-screw extruder for end-capping modification, and then extruding. It is made by taking it out, drawing it into strips and cutting it into granules.

Furthermore, the blocking agent includes one or more of maleic anhydride, phthalic anhydride, and pyromellitic anhydride.

Furthermore, the weight average molecular weight of the PPC is 30-120KDa.

Furthermore, the rotation speed of the high-speed mixing is 300-1000 rpm, and the mixing time is 5-10 minutes.

Furthermore, the extrusion temperature of the twin-screw extruder used is 120-175°C, the die temperature is 130-160°C, and the screw speed is 100-200 rpm.

Further, the weight average molecular weight of the PBAT is 70-150KDa.

Further, the weight average molecular weight of the PLA is 160-300KDa.

Further, the initiator is selected from one of bis-25 and dicumyl peroxide (DCP).

Further, the branching agent A is a polybutadiene liquid rubber with furan groups. It is first mixed with a hydroxyl-terminated polybutadiene liquid rubber and HDI in a molar ratio of 1:2, and reacted at 70°C for 60 minutes. , to prepare isocyanate-terminated polybutadiene liquid rubber, and then add furfurylamine at a molar ratio of 2:1 to isocyanate-terminated polybutadiene liquid rubber, and continue the insulation reaction at 70°C for 90 minutes.

Furthermore, the molecular weight of the hydroxyl-terminated polybutadiene liquid rubber is 1,000.

Further, the branching agent B is bismaleimide or modified bismaleimide.

Further, the antioxidant is one or more of tea polyphenols, antioxidant 1076, antioxidant 1010 or antioxidant 168.

Further, the slip agent is one or more of erucic acid amide, zinc stearate, ethylene bis stearamide and polyethylene wax.

The preparation of the biodegradable bubble film includes the following steps:

(1) Dry PBAT, PLA and modified PPC separately;

(2) Weigh the dried PBAT, PLA and modified PPC, mix them with the initiator, antioxidant, branching agent A, branching agent B and slip agent in proportion in a high-speed mixer at high speed;

(3) Place the mixed materials in a twin-screw extruder to melt and blend, and extrude and granulate to obtain blended pellets;

(4) Put the obtained blended pellets into a bubble film casting machine for extrusion, traction, and winding, and finally obtain the biodegradable bubble film.

Further, the drying temperature in step (1) is 60-100°C, and the drying time is 2-12 hours.

Further, the rotation speed of the high-speed mixing described in step (2) is 300-1000rpm, and the mixing time is 5-10min;

Further, in step (3), the extrusion temperature of the twin-screw extruder is 120-190°C, the die temperature is 130-160°C, and the screw speed is 100-300 rpm.

Further, in step (4), the extrusion temperature of the bubble film casting machine is 160-230°C, the die temperature is 180-230°C, and the screw speed is 50-200rpm.

The beneficial effects of the present invention are:

1. Compared with traditional PE bubble film, the main components in the present invention are biodegradable materials, so that the prepared bubble film can be fully biodegraded into carbon dioxide and water, which is green and environmentally friendly.

2. The present invention uses PBAT, PLA and modified PPC as main materials to prepare bubble films. The combination of flexible PBAT and rigid PLA can prepare a blend with good flexibility. PPC is a carbon dioxide-based biodegradable plastic with low cost and good compatibility with PBAT and PLA, and PPC has good barrier properties. It has good performance. Introducing PPC into the PBAT/PLA blend can improve the mechanical properties and air retention of the bubble film. In view of the problem of poor thermal stability of PPC, the present invention carries out end-capping modification to improve the thermal stability and mechanical properties of PPC, thereby further improving the mechanical properties of the blend system.

3. Liquid polybutadiene can increase the mobility of resin molecular chains, improve the smoothness of the processing process, lower the melting point of PLA, and improve the heat sealing performance of bubble film. Polybutadiene liquid rubber is a reactive plasticizer. The double bonds on its molecular chain can undergo a grafting reaction with polymers (PPC, PBAT and PLA) under the action of an initiator to grow hydrophobic grafts. The branch chains are entangled with the molecular chains of the polymer matrix or with each other, which not only forms a denser molecular chain structure, but also improves the interface bonding strength between different polymers, so it can greatly improve the matrix. Resin barrier properties. Polybutadiene liquid rubber with furan groups in the molecular chain can form a cross-linked structure in the presence of bismaleimide, further increasing the entanglement density of the molecular chain and improving the mechanical properties of the blended modification system. and barrier properties.

4. Polymers and their blends with permanent covalently cross-linked macromolecular networks generally cannot be reprocessed or reshaped, and the introduction of covalent crosslinks can easily cause low polymer processing efficiency. The present invention uses polybutadiene liquid rubber with furan groups and (modified) bismaleimide to introduce dynamic covalent cross-linking bonds, which can realize the molecular chain cross-linking structure design of polymers and their blends. , due to the reversibility of dynamic covalent bonds, the performance of the blend can be improved directly during the polymer screw processing process. It is easy to achieve large-scale production without causing a reduction in polymer processing efficiency. The prepared blends undergo dynamic covalent cross-linking bonds during high-temperature processing, giving the polymer excellent processing properties. After low-temperature molding, the dynamic characteristic covalent bonds recombine to form covalent cross-linking bonds, increasing blending physical properties of objects.

5. The present invention has simple steps and strong operability. In view of the current problem of high prices of degradable materials, the use of this technical method is of great significance and value to the development of a circular economy of degradable materials.

Detailed ways

A biodegradable bubble film, the preparation of which includes the following steps:

(1) Vacuum dry PBAT, PLA, and modified PPC at 60-100°C for 2-12 hours;

(2) In terms of parts by mass, weigh 60-90 parts of dried PBAT, 5-20 parts of PLA, 5-20 parts of modified PPC, and 0.1-5 parts of initiator, 0.2-1 part of antioxidant, 0.1-5.0 parts of branching agent A, 0.1-5.0 parts of branching agent B and 0.1-1 part of slip agent are placed in a high-speed mixer and mixed at a high speed of 300-1000rpm for 5-10 minutes;

(3) Place the mixed materials in a twin-screw extruder to melt and blend, and extrude and granulate to obtain blended pellets; the extrusion temperature of the twin-screw extruder is 120-190°C, and the die temperature is 130- 160℃, screw speed 100-300rpm;

(4) Put the obtained blended pellets into a bubble film casting machine for extrusion, traction, and winding to finally obtain the biodegradable bubble film; the extrusion temperature of the bubble film casting machine is 160-230°C , the die temperature is 180-230℃, and the screw speed is 50-200rpm.

Wherein, the weight average molecular weight of PBAT described in step (1) is 70-150KDa. The weight average molecular weight of the PLA is 160-300KDa. The modified PPC is to mix PPC and end-capping agent in a high-speed mixer at a mass ratio of 100:0.5, and then add the mixture to a twin-screw extruder for end-capping modification, and then extrusion and drawing. It is prepared by strips and cutting into granules. The end-capping agent used includes one or more of maleic anhydride, phthalic anhydride and pyromellitic anhydride. The weight average molecular weight of the PPC used is 30-120KDa. The rotation speed of the high-speed mixing is 300-1000rpm, mixing time is 5-10min, the extrusion temperature of the twin-screw extruder used is 120-175℃, the die temperature is 130-160℃, and the screw speed is 100-200rpm.

The initiator in step (2) is selected from one of bis-25 and DCP. The branching agent A is first mixed with hydroxyl-terminated polybutadiene liquid rubber and HDI at a molar ratio of 1:2, reacted at 70°C for 60 minutes, to obtain isocyanate-terminated polybutadiene liquid rubber, and then sealed with isocyanate. The molar ratio of the terminal polybutadiene liquid rubber is 2:1. Add furfurylamine and continue the insulation reaction at 70°C for 90 minutes to obtain the polybutadiene liquid rubber containing furan groups. The molecular weight of the hydroxyl-terminated polybutadiene liquid rubber used. is 1000. The branching agent B is bismaleimide or modified bismaleimide. The antioxidant is one or more of tea polyphenols, antioxidant 1076, antioxidant 1010 or antioxidant 168. The slip agent is one or more of erucic acid amide, zinc stearate, ethylene bis stearamide and polyethylene wax.

In order to make the content of the present invention easier to understand, the technical solutions of the present invention will be further described below in conjunction with specific embodiments, but the present invention is not limited thereto.

The modified PPC used is to place PPC (weight average molecular weight 95KDa) and maleic anhydride (MA) in a high-speed mixer at a mass ratio of 100:0.5, mix at a high speed of 500 rpm for 10 minutes, and then add the mixture to the twin-screw extruder. End-capping modification is carried out in the extruder, and then it is obtained by extrusion, drawing and pelletizing. The extrusion temperature of the twin-screw extruder is 120-175-175-175-175-175-175-175-175- 175-175℃, die head temperature is 160℃, screw speed is 200rpm.

The polybutadiene liquid rubber with furan groups used is first mixed with hydroxyl-terminated polybutadiene liquid rubber (molecular weight: 1000) and HDI in a molar ratio of 1:2, and reacted at 70°C for 60 minutes to prepare isocyanate-terminated polybutadiene. Butadiene liquid rubber is then prepared by adding furfurylamine at a molar ratio of 2:1 to isocyanate-terminated polybutadiene liquid rubber, and continuing the insulation reaction at 70°C for 90 minutes.

Example 1

A biodegradable bubble film, its preparation method includes the following steps:

(1) Vacuum dry PBAT, PLA, and modified PPC at 60°C for 5 hours;

(2) In terms of parts by mass, weigh 75.0 parts of dried PBAT, 8.5 parts of PLA, 10.0 parts of modified PPC, 3.0 parts of polybutadiene liquid rubber with furan groups, and 1.5 parts of maleimide. , 0.5 parts of antioxidant 168, 0.5 parts of antioxidant 10100.5 parts, 0.5 parts of double 25 and 0.5 parts of erucamide are placed in a high-speed mixer and mixed at a high speed of 500 rpm for 10 minutes;

(3) Place the mixed materials in a twin-screw extruder to melt and blend, and extrude and granulate to obtain special blending materials; the extrusion temperature of the twin-screw extruder is 120-175-175-175-175- 175-175-175-175-175-175℃, die head temperature 160℃, screw speed 200rpm;

(4) Put the obtained blended pellets into a bubble film casting machine for extrusion, traction, and winding to finally obtain biodegradable bubble film; the extrusion temperature of the bubble film casting machine is 150-175-180- 185-185℃, die head temperature is 200-195-190-185-185-190-195-200℃, screw speed is 200rpm.

Example 2

A biodegradable bubble film, its preparation method includes the following steps:

(1) Vacuum dry PBAT, PLA, and modified PPC at 60°C for 5 hours;

(2) In terms of parts by mass, weigh 70.0 parts of dried PBAT, 8.5 parts of PLA, 15.0 parts of modified PPC, 3.0 parts of polybutadiene liquid rubber with furan groups, and 1.5 parts of maleimide. , 0.5 parts of antioxidant 168, 0.5 parts of antioxidant 10100.5 parts, 0.5 parts of double 25 and 0.5 parts of erucamide are placed in a high-speed mixer and mixed at a high speed of 500 rpm for 10 minutes;

(3) Place the mixed materials in a twin-screw extruder to melt and blend, and extrude and granulate to obtain special blending materials; the extrusion temperature of the twin-screw extruder is 120-175-175-175-175- 175-175-175-175-175-175℃, die head temperature 160℃, screw speed 200rpm;

(4) Put the obtained blended pellets into a bubble film casting machine for extrusion, traction, and winding to finally obtain biodegradable bubble film; the extrusion temperature of the bubble film casting machine is 150-175-180- 185-185℃, die head temperature is 200-195-190-185-185-190-195-200℃, screw speed is 200rpm.

Example 3

A biodegradable bubble film, its preparation method includes the following steps:

(1) Vacuum dry PBAT, PLA, and modified PPC at 60°C for 5 hours;

(2) In terms of parts by mass, weigh 65.0 parts of dried PBAT, 8.5 parts of PLA, 20.0 parts of modified PPC, 3.0 parts of polybutadiene liquid rubber with furan groups, and 1.5 parts of maleimide 0.5 parts of antioxidant 168, 0.5 parts of antioxidant 1010, 0.5 parts of double 25 and 0.5 parts of erucamide are placed in a high-speed mixer and mixed at a high speed of 500 rpm for 10 minutes;

(3) Place the mixed materials in a twin-screw extruder to melt and blend, and extrude and granulate to obtain special blending materials; the extrusion temperature of the twin-screw extruder is 120-175-175-175-175- 175-175-175-175-175-175℃, die head temperature 160℃, screw speed 200rpm;

(4) Put the obtained blended pellets into a bubble film casting machine for extrusion, traction, and winding to finally obtain biodegradable bubble film; the extrusion temperature of the bubble film casting machine is 150-175-180- 185-185℃, die head temperature is 200-195-190-185-185-190-195-200℃, screw speed is 200rpm.

Example 4

A biodegradable bubble film, its preparation method includes the following steps:

(1) Vacuum dry PBAT, PLA, and modified PPC at 60°C for 5 hours;

(2) In terms of parts by mass, weigh 55.0 parts of dried PBAT, 8.5 parts of PLA, 30.0 parts of modified PPC, 3.0 parts of polybutadiene liquid rubber with furan groups, and 1.5 parts of maleimide 0.5 parts of antioxidant 168, 0.5 parts of antioxidant 1010, 0.5 parts of double 25 and 0.5 parts of erucamide are placed in a high-speed mixer and mixed at a high speed of 500 rpm for 10 minutes;

(3) Place the mixed materials in a twin-screw extruder to melt and blend, and extrude and granulate to obtain special blending materials; the extrusion temperature of the twin-screw extruder is 120-175-175-175-175- 175-175-175-175-175-175℃, die head temperature 160℃, screw speed 200rpm;

(4) Put the obtained blended pellets into a bubble film casting machine for extrusion, traction, and winding to finally obtain biodegradable bubble film; the extrusion temperature of the bubble film casting machine is 150-175-180- 185-185℃, die head temperature is 200-195-190-185-185-190-195-200℃, screw speed is 200rpm.

Comparative example 1

A degradable bubble film, the preparation method of which includes the following steps:

(1) Vacuum dry PBAT, PLA, and modified PPC at 60°C for 5 hours;

(2) In terms of parts by mass, weigh 65.0 parts of dried PBAT, 8.5 parts of PLA, 20.0 parts of modified PPC, 3.0 parts of hydroxyl-terminated polybutadiene liquid rubber, 1.5 parts of maleimide, and antioxidant Place 0.5 parts of agent 168, 0.5 parts of antioxidant 1010, 0.5 parts of bis-25 and 0.5 parts of erucamide in a high-speed mixer, and mix at a high speed of 500 rpm for 10 minutes;

(3) Place the mixed materials in a twin-screw extruder to melt and blend, and extrude and granulate to obtain special blending materials; the extrusion temperature of the twin-screw extruder is 120-175-175-175-175- 175-175-175-175-175-175℃, die head temperature 160℃, screw speed 200rpm;

(4) Put the obtained blended pellets into a bubble film casting machine for extrusion, traction, and winding to finally obtain biodegradable bubble film; the extrusion temperature of the bubble film casting machine is 150-175-180- 185-185℃, die head temperature is 200-195-190-185-185-190-195-200℃, screw speed is 200rpm.

Comparative example 2

A degradable bubble film, the preparation method of which includes the following steps:

(1) Vacuum dry PBAT, PLA, and PPC at 60°C for 5 hours;

(2) In terms of parts by mass, weigh 65.0 parts of dried PBAT, 8.5 parts of PLA, 20.0 parts of PPC, 3.0 parts of hydroxyl-terminated polybutadiene liquid rubber, 1.5 parts of maleimide, and 168 parts of antioxidants 0.5 parts, 0.5 parts of Antioxidant 1010, 0.5 parts of Double 250 and 0.5 parts of Erucamide are placed in a high-speed mixer and mixed at a high speed of 500 rpm for 10 minutes;

(3) Place the mixed materials in a twin-screw extruder to melt and blend, and extrude and granulate to obtain special blending materials; the extrusion temperature of the twin-screw extruder is 120-175-175-175-175- 175-175-175-175-175-175℃, die head temperature 160℃, screw speed 200rpm;

(4) Put the obtained blended pellets into a bubble film casting machine for extrusion, traction, and winding to finally obtain biodegradable bubble film; the extrusion temperature of the bubble film casting machine is 150-175-180- 185-185℃, die head temperature is 200-195-190-185-185-190-195-200℃, screw speed is 200rpm.

Comparative example 3

A degradable bubble film, the preparation method of which includes the following steps:

(1) Vacuum dry PBAT, PLA, and modified PPC at 60°C for 5 hours;

(2) In terms of parts by mass, weigh 65.0 parts of dried PBAT, 8.5 parts of PLA, 20.0 parts of modified PPC, 3.0 parts of PEG300, 1.5 parts of maleimide, 0.5 parts of antioxidant 168, antioxidant Place 0.5 parts of Agent 1010, 0.5 parts of Double 25 and 0.5 parts of erucamide in a high-speed mixer and mix at a high speed of 500 rpm for 10 minutes;

(3) Place the mixed materials in a twin-screw extruder to melt and blend, and extrude and granulate to obtain special blending materials; the extrusion temperature of the twin-screw extruder is 120-175-175-175-175- 175-175-175-175-175-175℃, die head temperature 160℃, screw speed 200rpm;

(4) Put the obtained blended pellets into a bubble film casting machine for extrusion, traction, and winding to finally obtain biodegradable bubble film; the extrusion temperature of the bubble film casting machine is 150-175-180- 185-185℃, die head temperature is 200-195-190-185-185-190-195-200℃, screw speed is 200rpm.

Comparative example 4

A biodegradable bubble film, its preparation method includes the following steps:

(1) Vacuum dry PBAT, PLA, and modified PPC at 60°C for 5 hours;

(2) In terms of parts by mass, weigh 65.0 parts of dried PBAT, 10 parts of PLA, 10.0 parts of modified PPC, 3.0 parts of polybutadiene liquid rubber with furan groups, 0.5 parts of antioxidant 168, 0.5 parts of Antioxidant 1010, 0.5 parts of Bi250 and 0.5 parts of Erucamide are placed in a high-speed mixer and mixed at a high speed of 500 rpm for 10 minutes;

(3) Place the mixed materials in a twin-screw extruder to melt and blend, and extrude and granulate to obtain special blending materials; the extrusion temperature of the twin-screw extruder is 120-175-175-175-175- 175-175-175-175-175-175℃, die head temperature 160℃, screw speed 200rpm;

(4) Put the obtained blended pellets into a bubble film casting machine for extrusion, traction, and winding to finally obtain biodegradable bubble film; the extrusion temperature of the bubble film casting machine is 150-175-180- 185-185℃, die head temperature is 200-195-190-185-185-190-195-200℃, screw speed is 200rpm.

Comparative example 5

A biodegradable bubble film, its preparation method includes the following steps:

(1) Vacuum dry PBAT, PLA, and modified PPC at 60°C for 5 hours;

(2) In terms of parts by mass, weigh 68.0 parts of dried PBAT, 8.5 parts of PLA, 20.0 parts of modified PPC, 1.5 parts of maleimide, 0.5 parts of antioxidant 168, and 0.5 parts of antioxidant 1010 , 0.5 parts of double 25 and 0.5 parts of erucamide are placed in a high-speed mixer and mixed at a high speed of 500 rpm for 10 minutes;

(3) Place the mixed materials in a twin-screw extruder to melt and blend, and extrude and granulate to obtain special blending materials; the extrusion temperature of the twin-screw extruder is 120-175-175-175-175- 175-175-175-175-175-175℃, die head temperature 160℃, screw speed 200rpm;

(4) Put the obtained blended pellets into a bubble film casting machine for extrusion, traction, and winding to finally obtain biodegradable bubble film; the extrusion temperature of the bubble film casting machine is 150-175-180- 185-185℃, die head temperature is 200-195-190-185-185-190-195-200℃, screw speed is 200rpm.

Performance tests were performed on the degradable bubble films obtained in the Examples and Comparative Examples, and the test results are shown in Table 1.

Table 1 Performance test results of degradable bubble films obtained in Examples and Comparative Examples

Through comparison of Examples 1-4, it can be found that in the blend system, when the PLA content remains unchanged, as the modified PPC content increases, the tensile strength of the sample significantly decreases, and the elongation at break remains at higher level. Therefore, in order to ensure that the film has high tensile strength, the amount of modified PPC should be controlled to obtain a film material with good comprehensive properties. When the added amount of modified PPC is 15%, the tensile strength of the film material is optimal.

Through comparison between Example 3 and Comparative Example 1, it can be found that the degradable bubble film prepared by using furan group-modified polybutadiene liquid rubber has better mechanical properties than the degradable air bubble film prepared by ordinary hydroxyl-terminated polybutadiene liquid rubber. It has more advantages in performance and heat sealing strength. This is because the polybutadiene liquid rubber with furan groups can form a cross-linked structure in the presence of bismaleimide, which further increases the entanglement density of the molecular chains and improves the mechanical properties of the blend system.

Through comparison between Example 3 and Comparative Examples 1 and 2, it can be found that PPC is a brittle material under normal temperature conditions, and the use of maleic anhydride for end-capping modification can significantly improve the thermal stability and melt strength of PPC, making it It is easy to process stably, and the use of maleic anhydride end-capped PPC to replace ordinary PPC can significantly improve the mechanical properties of the resulting film. In addition, PPC is a material with good barrier properties. Adding PPC to a large extent while ensuring high mechanical properties can improve the barrier properties of biodegradable bubble film.

By comparing Example 3 and Comparative Example 3, it can be found that when PEG is used to replace the liquid polybutadiene rubber with furan groups, the tensile strength and elongation at break of the resulting film are significantly reduced. This is due to the combination of PEG and polymerization. The material matrix has poor compatibility, is an unstable composition during the application process, and is easy to precipitate, making it difficult to meet the needs of practical applications.

By comparing Example 3 with Comparative Examples 4 and 5, it can be found that if the polybutadiene liquid rubber with furan groups is used alone as the branching agent, or the bismaleimide is used alone as the branching agent, the film's The tensile strength and elongation at break are significantly reduced, proving that the combination of the two can exert obvious advantages.

The above are only preferred embodiments of the present invention, and all equivalent changes and modifications made in accordance with the patentable scope of the present invention shall fall within the scope of the present invention.

Claims (10)

1. A biodegradable bubble film, characterized in that it includes the following components in terms of parts by mass: 5-20 parts of modified PPC, 60-90 parts of PBAT, 5-20 parts of PLA, and 0.1-5 initiator parts, branching agent A 0.1-5.0 parts, branching agent B 0.1-5.0 parts, antioxidant 0.2-1 part and slip agent 0.1-1 part. 2. A biodegradable bubble film according to claim 1, characterized in that the modified PPC is made by placing PPC and end-capping agent in a high-speed mixer at a mass ratio of 100:0.5, and then mixing them at high speed. The mixture is added to a twin-screw extruder for end-capping modification, and is then extruded, drawn, and pelletized. 3. A biodegradable bubble film according to claim 2, characterized in that the end-capping agent includes one or more of maleic anhydride, phthalic anhydride, and pyromellitic anhydride; the PPC The weight average molecular weight is 30-120KDa; the rotation speed of the high-speed mixing is 300-1000rpm, and the mixing time is 5-10min; the extrusion temperature of the twin-screw extruder used is 120-175℃, and the die temperature is 130-160℃ , the screw speed is 100-200rpm. 4. A biodegradable bubble film according to claim 1, characterized in that the branching agent A is polybutadiene liquid rubber with furan groups, which is made by first adding hydroxyl-terminated polybutadiene. Mix olefin liquid rubber and HDI at a molar ratio of 1:2 and react at 70°C for 60 minutes to obtain an isocyanate-terminated polybutadiene liquid rubber. The molar ratio to the isocyanate-terminated polybutadiene liquid rubber is 2:1. Add furfurylamine and continue the heat preservation reaction for 90 minutes to obtain the product; the molecular weight of the hydroxyl-terminated polybutadiene liquid rubber is 1,000. 5. A biodegradable bubble film according to claim 1, characterized in that the branching agent B is bismaleimide or modified bismaleimide. 6. A biodegradable bubble film according to claim 1, characterized in that the weight average molecular weight of the PBAT is 70-150KDa; the weight average molecular weight of the PLA is 160-300KDa; the initiator is selected One of bis-25 and DCP; the antioxidant is one or more of tea polyphenols, antioxidant 1076, antioxidant 1010 or antioxidant 168. 7. A biodegradable bubble film according to claim 1, characterized in that its preparation includes the following steps: (1) Dry PBAT, PLA and modified PPC separately; (2) Weigh the dried PBAT, PLA and modified PPC, mix them with the initiator, antioxidant, branching agent A, branching agent B and slip agent in proportion in a high-speed mixer at high speed; (3) Place the mixed materials in a twin-screw extruder to melt and blend, and extrude and granulate to obtain blended pellets; (4) Put the obtained blended pellets into a bubble film casting machine for extrusion, traction, and winding, and finally obtain the biodegradable bubble film. 8. A biodegradable bubble film according to claim 7, characterized in that the high-speed mixing speed in step (2) is 300-1000 rpm, and the mixing time is 5-10 min. 9. A biodegradable bubble film according to claim 7, characterized in that in step (3), the extrusion temperature of the twin-screw extruder is 120-190°C, the die temperature is 130-160°C, and the screw speed is 100-300rpm. 10. A biodegradable bubble film according to claim 7, characterized in that in step (4), the extrusion temperature of the bubble film casting machine is 160-230°C, and the die temperature is 180-230°C. The screw speed is 50-200rpm.