Degradable PBAT modified material, preparation method and application thereof

Abstract

The application provides a degradable PBAT modified material and a preparation method and application thereof. The material is prepared from the following raw materials: PBAT, aminophenylcyclohexane, a decomposition agent, an alkenyl glycidyl ether, a phenyl glycidyl ether and a slip agent. The application generates a reaction functional group by partially decomposing PBAT, uses a double screw to incorporate o-diallyl bisphenol A diglycidyl ether into PBAT blending reaction, simultaneously blends high-compatibility aminophenylcyclohexane reaction grafting, limits PBAT crystallization and improves transparency, and uses phenyl glycidyl ether capping to improve the distribution of double bonds and high-reactivity benzene rings. During the blowing film processing, one-time forming is performed through a certain amount of electron beam irradiation, compared with conventional PBAT electron beam irradiation films, the heat shrinkage rate is obviously improved, the transparency is higher, and the processing is stable.

Description

Technical Field

[0001] This invention belongs to the field of biodegradable plastics, specifically relating to a biodegradable PBAT modified material, its preparation method, and its application. Background Technology

[0002] With the increasing use of plastics, the white pollution problem caused by traditional non-biodegradable plastics can no longer be ignored. Currently, more and more countries are actively promoting the use of recyclable / biodegradable polymers. Biodegradable plastics have become the most effective way to solve the environmental pollution problem of single-use packaging products in recent years. PBAT is currently one of the most widely used bio-based biodegradable plastics, possessing excellent tensile strength, processability, and complete biodegradability, comparable to traditional PE. This is why it is widely used to replace traditional non-biodegradable plastics in packaging, medical applications, and other fields. However, in the field of heat shrink film, PBAT cannot replace PE on a large scale due to its price, low shrinkage rate, and hardness. As the market gradually develops, the price and cost of PBAT have continued to decline, and the price difference with PE is now within an acceptable range. Therefore, the development of high-shrinkage, high-hardness biodegradable heat shrink film has a promising market prospect.

[0003] CN 113717416 discloses an irradiated heat-shrinkable biodegradable plastic film and its preparation method, mainly using triallyl isocyanurate as a sensitizer to irradiate and crosslink PBAT and starch. However, the actual reactivity of the benzene ring in PBAT is not high, and the heat-shrinking effect of direct irradiation crosslinking is not good. CN 114456563 discloses a PLA-based heat-shrinkable film and its preparation method, using PLA with EAA compatibility to increase toughness and shrinkage rate. However, PLA is still too hard compared to PBAT, making it unsuitable as a shrink film. CN 115674626 discloses a method for preparing a biodegradable heat-shrinkable film, using PBAT as a substrate for transverse and longitudinal stretching, and using a high stretch ratio to obtain a better shrinkage rate. However, this method has cumbersome processing steps and expensive processing equipment, making it unsuitable for mass production.

[0004] Therefore, it is essential to conduct research on PBAT substrates and develop a biodegradable heat-shrinkable film with high shrinkage rate formed in a single blown film process. Summary of the Invention

[0005] To address the aforementioned problems in the existing technology, one of the objectives of this invention is to provide a biodegradable PBAT modified material that maintains a longitudinal and transverse heat shrinkage rate >60% / 10%, a modulus close to that of PE, an Elmondov tear strength >3000mN, and toughness significantly superior to the PLA heat-shrinkable film system. Furthermore, this material is simple to process and meets the requirements for normal heat-shrinkable applications.

[0006] To achieve the above technical effects, the technical solution adopted by the present invention is as follows:

[0007] A biodegradable PBAT-modified material, said material being prepared from raw materials comprising the following parts by weight:

[0008] 75-95 parts of PBAT resin, preferably 85-95 parts;

[0009] Aminophenylcyclohexane, 1-15 parts, preferably 5-10 parts;

[0010] The decomposing agent is 0.3 to 2 parts, preferably 0.5 to 0.8 parts;

[0011] 1 to 10 parts of alkenyl glycidyl ether, preferably 3 to 7 parts;

[0012] 1 to 10 parts of phenyl glycidyl ether, preferably 2 to 5 parts;

[0013] The amount of slip agent is 0.1 to 0.5 parts, preferably 0.2 to 0.4 parts.

[0014] The inventors discovered that by partially decomposing PBAT to generate reactive functional groups, they used a twin-screw extruder to incorporate o-diallylbisphenol A diglycidyl ether into the PBAT blend. Simultaneously, highly compatible aminophenylcyclohexane was incorporated for grafting, restricting PBAT crystallization and improving transparency. Furthermore, phenyl glycidyl ether was used for end-capping, increasing the distribution of double bonds and highly reactive benzene rings. During blown film processing, a specific amount of electron beam irradiation was used for one-step forming. Compared to conventional PBAT electron-irradiated films, this method significantly improved thermal shrinkage, increased transparency, and enhanced processing stability.

[0015] In one embodiment of the present invention, the PBAT resin has a weight-average molecular weight of 50,000 to 1,800,000 and an acid value of 10 to 40 mol / t; preferably, the molecular weight is 140,000 to 150,000 and the acid value is 20 to 30 mol / t.

[0016] In one embodiment of the present invention, the alkenyl glycidyl ether is a C10-C30 glycidyl ether containing a double bond, preferably one or more of o-diallylbisphenol A diglycidyl ether, 4-vinylbenzyl glycidyl ether, and allyl glycidyl ether, more preferably o-diallylbisphenol A diglycidyl ether.

[0017] In one embodiment of the present invention, the phenyl glycidyl ether is a C10-C20 glycidyl ether containing an aromatic ring, preferably one or more of 2-toluene glycidyl ether, 2-biphenyl glycidyl ether, and p-tert-butylphenyl glycidyl ether, and more preferably 2-toluene glycidyl ether.

[0018] In one embodiment of the present invention, the aminophenylcyclohexane is a C18-C38 diaminocyclohexane containing an aromatic ring, preferably 1,1-bis(4-aminophenyl)cyclohexane and / or 4,4-diamino-3,3-dimethyldiphenylcyclohexane, more preferably 1,1-bis(4-aminophenyl)cyclohexane.

[0019] In one embodiment of the invention, the decomposing agent is a dicarboxylic acid compound and / or a tricarboxylic acid compound compatible with PBAT, preferably one or more of maleic acid, succinic acid, terephthalic acid or their C4-C8 homologues, more preferably succinic acid and / or maleic acid.

[0020] In one embodiment of the present invention, the slip agent is an amide slip agent, preferably one or more of erucamide, oleamide, and behenamide, more preferably erucamide and / or oleamide.

[0021] Another objective of this invention is to provide a method for preparing a biodegradable PBAT modified material.

[0022] A method for preparing a biodegradable PBAT modified material, wherein the modified material is the material described above, and the preparation method includes the following steps: alkenyl glycidyl ether, phenyl glycidyl ether, aminophenylcyclohexane, and a slip agent are mixed and fed into a twin-screw extruder through a side feed port; PBAT resin and a decomposing agent are mixed and fed into a twin-screw extruder through a main feed port; after extrusion, the mixture is water-cooled and granulated to obtain the biodegradable PBAT modified material.

[0023] Another object of the present invention is to provide a use for a biodegradable PBAT modified material.

[0024] Use of a biodegradable PBAT modified material, wherein the modified material is the material described above or the material prepared by the method described above, and the modified material is used to prepare membrane materials, preferably for preparing shrink films.

[0025] Another object of the present invention is to provide a shrink film.

[0026] A shrink film, wherein the shrink film is prepared using the above-mentioned biodegradable PBAT modified material, or using the above-mentioned preparation method to prepare a biodegradable PBAT modified material, wherein the shrink film has a longitudinal and transverse thermal shrinkage rate >60% / 20% and a haze <10%.

[0027] Another object of the present invention is to provide a method for preparing a shrink film.

[0028] A method for preparing a shrink film, wherein the shrink film is prepared using the above-mentioned biodegradable PBAT modified material, or prepared using the above-mentioned method using a biodegradable PBAT modified material, or is the above-mentioned shrink film, wherein an electron curtain accelerator is used in the method; preferably, the irradiation dose of the electron curtain accelerator is set to 10-200 kGy, more preferably 100-150 kGy.

[0029] Compared with the prior art, the beneficial effects of the technical solution of the present invention are as follows:

[0030] This invention, by restricting PBAT crystallization and irradiating it into shape, achieves a longitudinal and transverse heat shrinkage rate >60% / 10% compared to conventional biodegradable heat shrink films. It also exhibits significantly superior toughness compared to PLA heat shrink film systems, and is simple to process, meeting the requirements for normal heat shrink applications. Detailed Implementation

[0031] The present invention will be further illustrated below with specific embodiments. These embodiments are merely illustrative and do not limit the scope of the invention.

[0032] I. The main raw material sources in the embodiments and comparative examples of this invention are as follows:

[0033] PBAT resin: Wanhua Chemical;

[0034] 1,4-Succinic acid (decomposing agent): Sinopharm Group;

[0035] maleic acid: Maclean;

[0036] Terephthalic acid: Sinopharm Group;

[0037] o-Dearly allyl bisphenol A diglycidyl ether: Inokai Ltd.;

[0038] Allyl glycidyl ether: Inokai Ltd.;

[0039] 4-Vinylbenzyl glycidyl ether: Sinopharm Group;

[0040] 2-Toluene glycidyl ether: Inokai Ltd.;

[0041] p-tert-butylphenyl glycidyl ether: Guangdong Fangxin Biotechnology Co., Ltd.;

[0042] 4,4-Diamino-3,3-Dimethyldiphenylcyclohexane: Inokai Ltd.;

[0043] 1,1-Di(4-aminophenyl)cyclohexane: Inokai Ltd.;

[0044] Oleamide: Croda;

[0045] II. The main testing methods used in the embodiments and comparative examples of this invention are as follows:

[0046] The mechanical properties of the film were tested using an Instorn 5966 universal material tester in accordance with the national standard GB / T 1040.3-2006; gauge length 100 mm, tensile speed 500 mm / min, sample width 15 mm, length 150 mm, test temperature 23℃, humidity 50%.

[0047] Shrinkage test: The film heat shrinkage rate was tested in accordance with the national standard GB / T 4456-2008.

[0048] III. The main equipment information used in the embodiments and comparative examples of this invention is as follows:

[0049] Twin-screw extruder: screw diameter 32mm, length-to-diameter ratio 52, Coperion, ZSK Mv PLUS;

[0050] Film blowing machine: screw diameter 35mm, length-to-diameter ratio 32, die diameter 80mm, die clearance 0.2mm, Zhejiang Yunfeng Machinery Factory, YFFE-800.

[0051] Example 1

[0052] The steps for preparing biodegradable PBAT-modified materials are as follows:

[0053] Weigh 83.1 kg of PBAT resin with a weight-average molecular weight of 150,000 and an acid value of 25 mol / t, and 0.6 kg of 1,4-succinic acid. Mix them using a low-speed mixer at a speed of 20 r / min, and then feed them into the main feeder of a twin-screw extruder.

[0054] Weigh 0.3 kg of oleamide, 4 kg of 2-toluene glycidyl ether, 7 kg of o-diallyl bisphenol A diglycidyl ether, and 7 kg of 1,1-bis(4-aminophenyl)cyclohexane. Mix them using a low-speed mixer at a stirring speed of 20 r / min. Feed the mixture into the twin-screw extruder through the sixth zone of the barrel.

[0055] The twin-screw extruder's heating zone is divided into 14 zones, with temperatures set between 140 and 160°C. Zones 1-6 are set to temperatures of 140°C, 140°C, 150°C, 150°C, 150°C, 150°C; zones 7-10 are set to temperatures of 160°C, 160°C, 160°C, 160°C; and zones 11-14 are set to temperatures of 160°C, 160°C, 150°C, 150°C. The side feed port is located in zone 6, and the screw speed is set to 300 rpm.

[0056] After extrusion by a twin-screw extruder, the material is cooled by water and granulated to obtain biodegradable PBAT modified material.

[0057] The aforementioned biodegradable PBAT modified material was extruded using a single-screw blown film extruder and then passed through an electronic curtain accelerator to produce PBAT modified film material. The die diameter was 120 mm, and the screw length-to-diameter ratio was 32. The single-screw extruder contained 5 zones with temperature settings of 150℃, 160℃, 160℃, 160℃, and 150℃, respectively. The blow-up ratio was set to 3, and the capacity was set to 40 kg / h. The film thickness was set to 0.003 mm. The electronic curtain acceleration voltage was set to 200 kV, a nitrogen atmosphere was used, and the irradiation dose was set to 150 kGy.

[0058] The test results of the mechanical and thermal shrinkage properties of the obtained membrane material are shown in Table 1.

[0059] Example 2

[0060] The steps for preparing biodegradable PBAT-modified materials are as follows:

[0061] Weigh 84.2 kg of PBAT resin with a weight average molecular weight of 180,000 and an acid value of 10 mol / t, and 0.6 kg of maleic acid. Mix them using a low-speed mixer at a speed of 20 r / min, and then feed them into the main feeder of a twin-screw extruder.

[0062] Weigh 0.2 kg of oleamide, 10 kg of 2-2-biphenyl glycidyl ether, 3 kg of 4,4-diamino-3,3-dimethyldiphenylcyclohexane, and 2 kg of allyl glycidyl ether. Mix them using a low-temperature mixer at a stirring speed of 20 r / min. Feed the mixture into the twin-screw extruder through the sixth zone of the barrel.

[0063] The twin-screw extruder's heating zone is divided into 14 zones, with temperatures set between 140 and 160°C. Zones 1-6 are set to temperatures of 140°C, 140°C, 150°C, 150°C, 150°C, 150°C; zones 7-10 are set to temperatures of 160°C, 160°C, 160°C, 160°C; and zones 11-14 are set to temperatures of 160°C, 160°C, 150°C, 150°C. The side feed port is located in zone 6, and the screw speed is set to 300 rpm.

[0064] After extrusion by a twin-screw extruder, the material is cooled by water and granulated to obtain biodegradable PBAT modified material.

[0065] The aforementioned biodegradable PBAT modified material was extruded using a single-screw blown film extruder and then passed through an electronic curtain accelerator to produce PBAT modified film material. The die diameter was 120 mm, and the screw length-to-diameter ratio was 32. The single-screw extruder contained 5 zones with temperature settings of 150℃, 160℃, 160℃, 160℃, and 150℃, respectively. The blow-up ratio was set to 3, and the capacity was set to 40 kg / h. The film thickness was set to 0.003 mm. The electronic curtain acceleration voltage was set to 200 kV, a nitrogen atmosphere was used, and the irradiation dose was set to 100 kGy.

[0066] The test results of the mechanical and thermal shrinkage properties of the obtained membrane material are shown in Table 1.

[0067] Example 3

[0068] The steps for preparing biodegradable PBAT-modified materials are as follows:

[0069] Weigh 68.8 kg of PBAT resin with a weight average molecular weight of 60,000 and an acid value of 40 mol / t, and 0.8 kg of terephthalic acid. Mix them using a low-speed mixer at a speed of 20 r / min, and then feed them into the main feeder of a twin-screw extruder.

[0070] Weigh 0.4 kg of oleamide, 5 kg of 2,4-vinylbenzyl glycidyl ether, 15 kg of 1,1-di(4-aminophenyl)cyclohexane, and 10 kg of p-tert-butylphenyl glycidyl ether. Mix them using a low-temperature mixer at a stirring speed of 20 r / min. Feed the mixture into the twin-screw extruder via the sixth zone side feeder.

[0071] The twin-screw extruder's heating zone is divided into 14 zones, with temperatures set between 140 and 160°C. Zones 1-6 are set to temperatures of 140°C, 140°C, 150°C, 150°C, 150°C, 150°C; zones 7-10 are set to temperatures of 160°C, 160°C, 160°C, 160°C; and zones 11-14 are set to temperatures of 160°C, 160°C, 150°C, 150°C. The side feed port is located in zone 6, and the screw speed is set to 300 rpm.

[0072] After extrusion by a twin-screw extruder, the material is cooled by water and granulated to obtain biodegradable PBAT modified material.

[0073] The aforementioned biodegradable PBAT modified material was extruded using a single-screw blown film extruder and then passed through an electronic curtain accelerator to produce PBAT modified film material. The die diameter was 120 mm, and the screw length-to-diameter ratio was 32. The single-screw extruder contained 5 zones with temperature settings of 150℃, 160℃, 160℃, 160℃, and 150℃, respectively. The blow-up ratio was set to 3, and the capacity was set to 40 kg / h. The film thickness was set to 0.003 mm. The electronic curtain acceleration voltage was set to 200 kV, a nitrogen atmosphere was used, and the irradiation dose was set to 120 kGy.

[0074] The test results of the mechanical and thermal shrinkage properties of the obtained membrane material are shown in Table 1.

[0075] Comparative Example 1

[0076] The method of Example 1 was followed, except that o-diallylbisphenol A diglycidyl ether was not added, while other operations and conditions remained unchanged, to obtain PBAT modified material, which was then extruded into a film.

[0077] The test results of the mechanical and thermal shrinkage properties of the obtained membrane material are shown in Table 1.

[0078] Comparative Example 2

[0079] The method of Example 2 was followed, except that 2-toluene glycidyl ether was not added, while other operations and conditions remained unchanged, to obtain PBAT modified material, which was then extruded into a film.

[0080] The test results of the mechanical and thermal shrinkage properties of the obtained membrane material are shown in Table 1.

[0081] Comparative Example 3

[0082] The method of Example 3 was followed, except that 1,1-bis(4-aminophenyl)cyclohexane was not added, while other operations and conditions remained unchanged, to obtain PBAT modified material, which was then extruded into a film.

[0083] The test results of the mechanical and thermal shrinkage properties of the obtained membrane material are shown in Table 1.

[0084] Table 1. Test results of mechanical and thermal shrinkage properties of membrane materials in each embodiment and comparative example.

[0085]

[0086] The PBAT pure material single-bubble blown film has a heat shrinkage rate of about 24% / 10%, which is poor heat shrinkage effect. In addition, the film modulus is too low, and the tightness after shrinkage is insufficient, which cannot play a role in fixing objects in place and cannot meet the requirements for shrink film use. As shown in Table 1, after modification by Examples 1-3 of the present invention, the film modulus is significantly improved, the shrinkage tightness is strong, and the shrinkage rate is higher than that of traditional PE single-bubble heat shrink film, reaching 60% in the longitudinal direction and more than 20% in the transverse direction. The film has high mechanical strength, indicating that the content of benzene rings inside the material is increased and the rigidity between molecules is enhanced. At the same time, it can be verified by Example 1 and Comparative Example 1 that the addition of o-diallyl bisphenol A diglycidyl ether can significantly increase the irradiation crosslinking efficiency of the film, improve the strength and heat shrinkage rate. In fact, without the addition of o-diallyl bisphenol A diglycidyl ether, the degradation rate of PBAT film after irradiation is much higher than the crosslinking rate, which will lead to a deterioration of material performance. Example 2 and Comparative Example 2 show that when only 2-toluene glycidyl ether is removed, the film modulus and rigidity decrease significantly, and the thermal shrinkage rate also decreases, indicating a reduction in irradiation crosslinking efficiency. In fact, irradiation crosslinking is a "bridging" reaction that opens the double bonds and abstracts hydrogen atoms from the benzene ring. The highly reactive benzene ring in the system is the key point for crosslinking, and the addition of 2-toluene glycidyl ether can increase the number of highly reactive benzene rings and increase the irradiation crosslinking efficiency. Example 3 and Comparative Example 3 show that when only aminophenylcyclohexane is removed, the film transparency decreases significantly due to the improved crystallinity of the material, and the shrinkage rate is also affected, resulting in a poor overall irradiation crosslinking effect.

Claims

1. A biodegradable PBAT-modified material, characterized in that, The material is prepared from raw materials comprising the following parts by weight: 75-95 parts of PBAT resin; 1-15 parts of aminophenylcyclohexane; 0.3-2 parts of decomposing agent; 1-10 parts of alkenyl glycidyl ether; 1-10 parts of phenyl glycidyl ether; 0.1 to 0.5 parts of slip agent; The decomposing agent is a dicarboxylic acid compound compatible with PBAT.

2. The modified material according to claim 1, characterized in that, The material is prepared from raw materials comprising the following parts by weight: 85-95 parts of PBAT resin; 5-10 parts of aminophenylcyclohexane; 0.5-0.8 parts of decomposing agent; 3-7 parts of alkenyl glycidyl ether; 2-5 parts of phenyl glycidyl ether; 0.2 to 0.4 parts of slip agent.

3. The modified material according to claim 1, characterized in that, The PBAT resin has a weight-average molecular weight of 50,000 to 1,800,000 and an acid value of 10 to 40 mol / L. And / or, the alkenyl glycidyl ether is a C10~C30 glycidyl ether containing a double bond; And / or, the phenyl glycidyl ether is a C10-C20 glycidyl ether containing an aromatic ring.

4. The modified material according to claim 3, characterized in that, The PBAT resin has a weight-average molecular weight of 140,000 to 150,000 and an acid value of 20 to 30 mol / t. And / or, the alkenyl glycidyl ether is one or more of o-diallylbisphenol A diglycidyl ether, 4-vinylbenzyl glycidyl ether, and allyl glycidyl ether; And / or, the phenyl glycidyl ether is one or more of 2-toluene glycidyl ether, 2-biphenyl glycidyl ether, and p-tert-butylphenyl glycidyl ether.

5. The modified material according to claim 4, characterized in that, The alkenyl glycidyl ether is o-diallylbisphenol A diglycidyl ether; And / or, the phenyl glycidyl ether is 2-toluene glycidyl ether.

6. The modified material according to claim 1 or 2, characterized in that, The aminophenylcyclohexane is a C18-C38 diaminocyclohexane containing an aromatic ring.

7. The modified material according to claim 6, characterized in that, The aminophenylcyclohexane is 1,1-bis(4-aminophenyl)cyclohexane and / or 4,4-diamino-3,3-dimethyldiphenylcyclohexane.

8. The modified material according to claim 7, characterized in that, The aminophenylcyclohexane is 1,1-bis(4-aminophenyl)cyclohexane.

9. The modified material according to claim 1, characterized in that, The decomposing agent is one or more of maleic acid, succinic acid, terephthalic acid, C4-C8 homologues of maleic acid, and C4-C8 homologues of succinic acid. And / or, the slip agent is an amide-based slip agent.

10. The modified material according to claim 9, characterized in that, The decomposing agents are succinic acid and / or maleic acid; And / or, the slip agent is one or more of erucamide, oleamide, and behenamide.

11. The modified material according to claim 10, characterized in that, The slip agent is erucamide and / or oleamide.

12. A method for preparing a biodegradable PBAT modified material, wherein the modified material is the material according to any one of claims 1-11, characterized in that, The preparation method includes the following steps: Alkenyl glycidyl ether, phenyl glycidyl ether, aminophenylcyclohexane, and a slip agent are mixed and fed into a twin-screw extruder through a side feed port. PBAT resin and a decomposing agent are mixed and fed into a twin-screw extruder through a main feed port. After extrusion, the mixture is water-cooled and granulated to obtain a biodegradable PBAT modified material.

13. Use of a biodegradable PBAT modified material, wherein the modified material is the material according to any one of claims 1-11, or the material prepared by the preparation method according to claim 12, and the modified material is used to prepare membrane materials.

14. The use according to claim 13, characterized in that, The modified material is used to prepare shrink film.

15. A shrink film, wherein the shrink film is prepared using the biodegradable PBAT modified material according to any one of claims 1-11, or using the biodegradable PBAT modified material prepared by the preparation method according to claim 12, wherein the shrink film has a longitudinal and transverse thermal shrinkage rate >56% / 20% and a haze <10%.

16. A method for preparing a shrink film, wherein the shrink film is prepared using the biodegradable PBAT modified material according to any one of claims 1-11, or using the biodegradable PBAT modified material prepared by the method of claim 12, or is the shrink film according to claim 15, characterized in that, The method uses an electron curtain accelerator.

17. The method according to claim 16, characterized in that, The irradiation dose of the electron curtain accelerator is set to 10~200kGy.

18. The method according to claim 17, characterized in that, The irradiation dose of the electron curtain accelerator is set to 100~150kGy.

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