Transparent biodegradable material and preparation method thereof

Abstract

The invention relates to a transparent biodegradable material and a preparation method thereof, and the transparent biodegradable material comprises the following components in parts by weight: 70-80 parts of PLA, 20-30 parts of PBAT-EG, 3-5 parts of an anti-reflection agent, 0.4 part of an antioxidant and 1-2 parts of a compatilizer. PBAT-EG is random copolyester obtained by introducing an ethylene glycol monomer in the preparation process of PBAT through copolymerization, and the ethylene glycol monomer accounts for 10-20 mol% of alcohol substances in all fed monomers; the preparation method comprises the following steps: uniformly mixing the PLA, the PBAT-EG, the anti-reflection agent, the antioxidant and the compatilizer through a mixer, and extruding and granulating through double screws to obtain the transparent biodegradable material. The problem that a conventional PBAT / PLA system is poor in transparency is solved, the prepared product is good in transparency and biodegradable, and product development in the field of film packaging is promoted.

Description

Technical Field

[0001] The present invention belongs to the technical field of degradable materials, and relates to a transparent biodegradable material and a preparation method thereof. Background Art

[0002] The PLA / PBAT composite system has been widely used in the field of film packaging as a substitute for traditional plastics such as polyethylene due to its biodegradability. However, its transparency is poorer compared to traditional plastic bags, and even the transparency of some film products is still not good. Even though high-transparency polylactic acid can be obtained by copolymerizing lactide such as racemic lactide at present, the opaque PBAT in the system is still a major factor leading to poor transparency of the composite system.

[0003] In the prior art, clarifying agents are often used for crystal regulation of products such as PP or PET to improve their transparency. However, the nucleating agents for PBAT have poor nucleating effect and poor transparency improvement effect, and are not widely used or are expensive, which limits their application in improving the transparency of the PLA / PBAT composite system.

[0004] Patent CN118374133A relates to a high-performance biodegradable film, which improves the transparency of the film. However, this patent is achieved by compounding biodegradable polyester amide and other materials, and has poor tear resistance and strength, and is prone to yellowing.

[0005] Patent CN116731298A relates to a modified polylactic acid copolyester and a high-transparency biodegradable heat-shrinkable film. However, this patent only relates to the preparation and transparency improvement of racemic lactide copolymerized polylactic acid, and does not consider the transparency improvement composite system of PBAT, and the transparency improvement effect still needs to be improved.

[0006] Therefore, it is of great significance to study a transparent biodegradable material and a preparation method thereof to solve the problems existing in the prior art. Summary of the Invention

[0007] The purpose of the present invention is to solve the problems existing in the prior art and provide a transparent biodegradable material and a preparation method thereof.

[0008] To achieve the above purpose, the technical scheme adopted by the present invention is as follows:

[0009] A transparent biodegradable material, comprising the following components in parts by weight:

[0010]

[0011] PBAT-EG is a random copolyester obtained by introducing ethylene glycol monomer during the preparation of PBAT through copolymerization. The ethylene glycol monomer accounts for 10-20 mol% of the alcohol substances in all the feed monomers.

[0012] In the PBAT structure of the present invention, 10-20 mol% of ethylene glycol monomer is introduced for copolymerization. The introduction of the ethylene glycol chain segment increases the crystallization difficulty, and at the same time, the ethylene terephthalate chain segment is introduced. This chain segment is similar to the PET structure and can be adapted to enhance the transparency with the transparency enhancer. Moreover, it still has good biodegradability at this ratio and chain segment length. It is compounded with PLA with good light transmittance, and a transparent biodegradable material is prepared by adding a compatibilizer and a transparency enhancer, which can be applied to the field of film packaging.

[0013] As a preferred technical solution:

[0014] For a transparent biodegradable material as described above, the number-average molecular weight of PBAT-EG is 20,000-30,000 g / mol, and the molecular weight distribution is 2-3.

[0015] For a transparent biodegradable material as described above, the light transmittance of the transparent biodegradable material is greater than 90%, and the controllable composting degradation time < 90 days.

[0016] For a transparent biodegradable material as described above, the antioxidants are antioxidant 1010 and antioxidant 168.

[0017] For a transparent biodegradable material as described above, the compatibilizer is ADR4368.

[0018] The present invention also provides a preparation method of a transparent biodegradable material as described in any one of the above. After mixing PLA, PBAT-EG, a transparency enhancer, antioxidants and a compatibilizer evenly by a mixer, a transparent biodegradable material is prepared by twin-screw extrusion granulation.

[0019] As a preferred technical solution:

[0020] For a preparation method of a transparent biodegradable material as described above, the rotation speed of the twin-screw extruder is 200-400 rpm, and the twin-screw processing temperature is 190-210 °C.

[0021] Beneficial effects:

[0022] (1) For the preparation method of a transparent biodegradable material of the present invention, by compounding PBAT-EG, PLA and a transparency enhancer, a transparent biodegradable material is prepared, which can be used in the film field, solves the problem of poor transparency of the conventional PBAT / PLA system. At the same time, due to the introduction of ethylene glycol monomer in PBAT-EG, the dosage of the original 1,4-butanediol is diluted, and the price is lower, which is beneficial to promoting the development of products in the film packaging field.

[0023] (2) For a transparent biodegradable material of the present invention, it has good transparency and is biodegradable. Specific embodiments

[0024] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of this application.

[0025] The test methods related to the performance indicators of the present invention are as follows:

[0026] Light transmittance: Test the light transmittance of a 15-μm transparent biodegradable material film.

[0027] Controlled composting degradation time: Test according to GB / T 19277.1-2011.

[0028] The sources of some substances of the present invention are as follows:

[0029] PLA: Commercially available from Anhui Fengyuan Polylactic Acid FY201.

[0030] Optical clarifier: Commercially available masterbatch of optical clarifier for PET, customized to replace the masterbatch matrix with PBAT matrix (Xinjiang Blueshirt Tunhe TH801T).

[0031] Antioxidant: Commercially available antioxidant 1010 and antioxidant 168.

[0032] Compatibilizer: Commercially available ADR4368.

[0033] Example 1

[0034] A preparation method of a transparent biodegradable material, the specific steps are as follows:

[0035] (1) In the presence of a catalyst, using ethylene glycol, 1,4-butanediol, terephthalic acid, and adipic acid as monomers to obtain a random copolyester by copolymerization, namely PBAT-EG. The number-average molecular weight of PBAT-EG is 20,000-30,000 g / mol, and the molecular weight distribution is 2-3;

[0036] Among them, the catalyst is antimony trioxide and tetrabutyl titanate. The proportion of antimony trioxide is three-thousandths of the total mass of terephthalic acid and adipic acid, and the proportion of tetrabutyl titanate is five-ten-thousandths of the total mass of terephthalic acid and adipic acid; the molar ratio of terephthalic acid to adipic acid is 1:1, the ethylene glycol monomer accounts for 10 mol% of the alcohol substances in all the feed monomers, and the alcohol-acid ratio is 1.3:1;

[0037] (2) By weight, 80 parts of PLA, 20 parts of PBAT-EG, 5 parts of clarifying agent, 0.2 part of antioxidant 1010, 0.2 part of antioxidant 168, and 1 part of compatibilizer are mixed evenly by a mixer and then processed by a twin-screw extruder to obtain a transparent biodegradable material through pelletizing. The rotational speed of the twin-screw extruder is 200 - 400 rpm, and the processing temperature of the twin-screw is 190 - 210 °C.

[0038] The light transmittance of the finally obtained transparent biodegradable material is 93%, and the controllable composting degradation time is 84 days.

[0039] Example 2

[0040] A preparation method of a transparent biodegradable material, the specific steps are as follows:

[0041] (1) In the presence of a catalyst, using ethylene glycol, 1,4-butanediol, terephthalic acid, and adipic acid as monomers to copolymerize to obtain a random copolyester, namely PBAT-EG. The number-average molecular weight of PBAT-EG is 20000 - 30000 g / mol, and the molecular weight distribution is 2 - 3;

[0042] Among them, the catalyst is antimony trioxide and tetrabutyl titanate. The proportion of antimony trioxide is three-thousandths of the total mass of terephthalic acid and adipic acid, and the proportion of tetrabutyl titanate is five-ten-thousandths of the total mass of terephthalic acid and adipic acid. The molar ratio of terephthalic acid to adipic acid is 1:1, the ethylene glycol monomer accounts for 15 mol% of the alcohol substances in all the charged monomers, and the alcohol-acid ratio is 1.3:1;

[0043] (2) By weight, 75 parts of PLA, 25 parts of PBAT-EG, 4 parts of clarifying agent, 0.2 part of antioxidant 1010, 0.2 part of antioxidant 168, and 1.5 parts of compatibilizer are mixed evenly by a mixer and then processed by a twin-screw extruder to obtain a transparent biodegradable material through pelletizing. The rotational speed of the twin-screw extruder is 200 - 400 rpm, and the processing temperature of the twin-screw is 190 - 210 °C.

[0044] The light transmittance of the finally obtained transparent biodegradable material is 96%, and the controllable composting degradation time is 78 days.

[0045] Example 3

[0046] A preparation method of a transparent biodegradable material, the specific steps are as follows:

[0047] (1) In the presence of a catalyst, using ethylene glycol, 1,4-butanediol, terephthalic acid, and adipic acid as monomers to copolymerize to obtain a random copolyester, namely PBAT-EG. The number-average molecular weight of PBAT-EG is 20000 - 30000 g / mol, and the molecular weight distribution is 2 - 3;

[0048] Among them, the catalyst is antimony trioxide and tetrabutyl titanate. The proportion of antimony trioxide is three-thousandths of the total mass of terephthalic acid and adipic acid, and the proportion of tetrabutyl titanate is five-ten-thousandths of the total mass of terephthalic acid and adipic acid; the molar ratio of terephthalic acid to adipic acid is 1:1, ethylene glycol monomer accounts for 20 mol% of the alcohol substances among all the charged monomers, and the alcohol-acid ratio is 1.3:1;

[0049] (2) By weight, 70 parts of PLA, 30 parts of PBAT-EG, 3 parts of clarifying agent, 0.2 parts of antioxidant 1010, 0.2 parts of antioxidant 168 and 2 parts of compatibilizer are mixed evenly by a mixer and then granulated by a twin-screw extruder to obtain a transparent biodegradable material; the rotation speed of the twin-screw extruder is 200-400 rpm, and the twin-screw processing temperature is 190-210 °C.

[0050] The light transmittance of the finally obtained transparent biodegradable material is 94%, and the controllable compost degradation time is 79 days.

Claims

1. A transparent biodegradable material, characterized in that The composition comprises the following components in parts by weight: PBAT-EG is a random copolyester obtained by copolymerization by introducing ethylene glycol monomer during the preparation process of PBAT, wherein the ethylene glycol monomer accounts for 10 to 20 mol% of the alcohol substances in all the feed monomers.

2. A transparent biodegradable material according to claim 1, characterized in that: The number average molecular weight of PBAT-EG is 20000-30000 g / mol, and the molecular weight distribution is 2-3.

3. A transparent biodegradable material according to claim 2, characterized in that: The light transmittance of the transparent biodegradable material is greater than 90%, and the controllable composting degradation time is less than 90 days.

4. The transparent biodegradable material according to claim 1, characterized in that: The antioxidants are antioxidant 1010 and antioxidant 168.

5. The transparent biodegradable material according to claim 1, characterized in that: The compatibilizer is ADR4368.

6. A method for preparing a transparent biodegradable material according to any one of claims 1 to 5, characterized in that: PLA, PBAT-EG, a permeability enhancer, an antioxidant and a compatibilizer are uniformly mixed in a mixer, and then granulated by twin-screw extrusion to obtain a transparent biodegradable material.

7. The method for preparing a transparent biodegradable material according to claim 6, characterized in that: The rotation speed of the twin-screw extruder is 200-400 rpm, and the processing temperature of the twin-screw is 190-210°C.

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