A high-strength biodegradable polylactic acid composite material and its application in the preparation of packaging materials

Abstract

This invention relates to the field of biodegradable material preparation technology, specifically disclosing a high-strength biodegradable polylactic acid (PLA) composite material and its application in the preparation of packaging materials. The high-strength biodegradable PLA composite material comprises the following raw material components in parts by weight: 60-90 parts of polylactic acid resin; 30-50 parts of polybutylene adipate / terephthalate; 0.1-1 parts of calcium carbonate; and 1-10 parts of polyethylene glycol. The PLA composite material of this invention exhibits high tensile strength; furthermore, the addition of wear-resistant filler silicon carbide further enhances the wear resistance of the PLA composite material.

Description

Technical Field

[0001] This invention relates to the field of biodegradable material preparation technology, and specifically discloses a high-strength biodegradable polylactic acid composite material and its application in the preparation of packaging materials. Background Technology

[0002] Polylactic acid (PLA) is a novel biodegradable material, a polyester polymer obtained by polymerizing lactic acid as the main raw material. In addition to its biodegradability, PLA products also possess advantages such as biocompatibility, transparency, and heat resistance; therefore, they are widely used in plastic products, packaged food, fast food containers, non-woven fabrics, and industrial and civilian textiles.

[0003] However, polylactic acid has low tensile strength, which needs to be further improved when used to prepare packaging materials. Summary of the Invention

[0004] In order to overcome at least one of the technical problems existing in the prior art, the present invention provides a high-strength biodegradable polylactic acid composite material.

[0005] The technical solution described in this invention is as follows:

[0006] A high-strength biodegradable polylactic acid composite material, comprising the following raw material components in parts by weight:

[0007] 60-90 parts polylactic acid resin; 30-50 parts poly(butylene adipate / terephthalate); 0.1-1 part calcium carbonate; 1-10 parts polyethylene glycol.

[0008] The polylactic acid composite material prepared by this invention has a tensile strength of over 70 MPa, exhibiting high strength.

[0009] Preferably, the high-strength biodegradable polylactic acid composite material comprises the following raw material components in parts by weight:

[0010] 70-80 parts polylactic acid resin; 30-40 parts poly(butylene adipate / terephthalate); 0.1-0.5 parts calcium carbonate; 3-5 parts polyethylene glycol.

[0011] Most preferably, the high-strength biodegradable polylactic acid composite material is characterized by comprising the following raw material components in parts by weight:

[0012] 80 parts polylactic acid resin; 40 parts poly(butylene adipate / terephthalate); 0.3 parts calcium carbonate; 3 parts polyethylene glycol.

[0013] Preferably, the high-strength biodegradable polylactic acid composite material further comprises silicon carbide.

[0014] Preferably, the silicon carbide content in the high-strength biodegradable polylactic acid composite material is 10 to 20 parts by weight.

[0015] Most preferably, the silicon carbide content in the high-strength biodegradable polylactic acid composite material is 15 parts by weight.

[0016] Preferably, the silicon carbide is modified silicon carbide;

[0017] The modified silicon carbide is prepared by the following method:

[0018] (1) Take silicon carbide and irradiate it with an electron accelerator. After the irradiation is completed, silicon carbide after irradiation treatment is obtained.

[0019] (2) Add the irradiated silicon carbide to an aqueous ethanol solution and stir until homogeneous to obtain a dispersion.

[0020] (3) Add lauramide propyl hydroxysulfonate betaine and pentaerythritol stearate to the dispersion, stir evenly, separate the solid, and dry the solid to obtain the modified silicon carbide.

[0021] To improve the wear resistance of polylactic acid composite materials, this invention incorporates silicon carbide as a wear-resistant filler into the polylactic acid composite material.

[0022] However, the inventors further discovered in their research that although adding silicon carbide can improve the wear resistance of polylactic acid composite materials, it also causes a certain degree of decrease in the tensile strength of polylactic acid composite materials.

[0023] To overcome this problem, the inventors made a surprising discovery during their research: adding modified silicon carbide prepared by the method described above to polylactic acid composite materials can significantly improve the tensile strength of polylactic acid composite materials compared to polylactic acid composite materials prepared by adding silicon carbide.

[0024] More preferably, the irradiation time in step (1) is 10 to 20 minutes and the irradiation dose is 40 to 60 kGy.

[0025] Most preferably, the irradiation time in step (1) is 15 min and the irradiation dose is 50 kGy.

[0026] More preferably, the ethanol aqueous solution mentioned in step (1) is an ethanol aqueous solution with an ethanol volume fraction of 50-70%.

[0027] Most preferably, the ethanol aqueous solution mentioned in step (1) is an ethanol aqueous solution with an ethanol volume fraction of 60%.

[0028] More preferably, in step (1), the weight ratio of irradiated silicon carbide to aqueous ethanol solution is 1:4 to 6.

[0029] Most preferably, the weight ratio of the irradiated silicon carbide to the aqueous ethanol solution in step (1) is 1:5.

[0030] More preferably, in step (3), the weight ratio of the dispersion to lauramide propyl hydroxysulfonate betaine and pentaerythritol stearate is 100:5-10:10-15.

[0031] Most preferably, in step (3), the weight ratio of the dispersion to lauramide propyl hydroxysulfonate betaine and pentaerythritol stearate is 100:7:13.

[0032] The preparation method of the above-mentioned high-strength biodegradable polylactic acid composite material includes the following steps:

[0033] Polylactic acid resin, polybutylene adipate / terephthalate, calcium carbonate and polyethylene glycol are mixed evenly, and then extruded and granulated by a twin-screw extruder to obtain the high-strength biodegradable polylactic acid composite material.

[0034] This invention also provides an application of a high-strength biodegradable polylactic acid composite material in the preparation of packaging materials.

[0035] Beneficial effects: This invention provides a novel high-strength biodegradable polylactic acid composite material; the polylactic acid composite material has high tensile strength; in addition, by adding wear-resistant filler silicon carbide, this invention also helps to improve the wear resistance of the polylactic acid composite material. Detailed Implementation

[0036] The present invention will be further explained below with reference to specific embodiments, but the embodiments do not limit the present invention in any way.

[0037] The polylactic acid resin used in the following examples is polylactic acid resin with the grade 2002D from NatureWorks, USA; the polybutylene adipate / terephthalate is PBAT resin with the grade TH801T from Xinjiang Lanshan Tunhe Company; the remaining raw materials are all conventional raw materials that can be purchased by those skilled in the art through conventional purchasing channels.

[0038] Example 1: Preparation of high-strength biodegradable polylactic acid composite material

[0039] Raw material composition by weight: 80 parts polylactic acid resin; 40 parts polybutylene adipate / terephthalate; 0.3 parts calcium carbonate; 3 parts polyethylene glycol 4000.

[0040] Preparation method: Polylactic acid resin, polybutylene adipate / terephthalate, calcium carbonate and polyethylene glycol are mixed evenly, and then extruded and granulated by a twin-screw extruder to obtain the high-strength biodegradable polylactic acid composite material.

[0041] Example 2: Preparation of high-strength biodegradable polylactic acid composite material

[0042] Raw material composition by weight: 80 parts polylactic acid resin; 40 parts polybutylene adipate / terephthalate; 0.3 parts calcium carbonate; 3 parts polyethylene glycol 4000; 15 parts silicon carbide;

[0043] Preparation method: Polylactic acid resin, polybutylene adipate / terephthalate, calcium carbonate, polyethylene glycol and silicon carbide are mixed evenly, and then extruded and granulated by a twin-screw extruder to obtain the high-strength biodegradable polylactic acid composite material.

[0044] Example 3: Preparation of high-strength biodegradable polylactic acid composite material

[0045] Raw material composition by weight: 80 parts polylactic acid resin; 40 parts polybutylene adipate / terephthalate; 0.3 parts calcium carbonate; 3 parts polyethylene glycol 4000; 15 parts modified silicon carbide;

[0046] The modified silicon carbide is prepared by the following method:

[0047] (1) Take silicon carbide and irradiate it with an electron accelerator. After the irradiation is completed, silicon carbide after irradiation treatment is obtained. The irradiation time is 15 min and the irradiation dose is 50 kGy.

[0048] (2) The irradiated silicon carbide is added to an ethanol aqueous solution and stirred evenly to obtain a dispersion; the ethanol aqueous solution is an ethanol aqueous solution with an ethanol volume fraction of 60%; the weight ratio of the irradiated silicon carbide to the ethanol aqueous solution is 1:5.

[0049] (3) Add lauramidopropyl hydroxysulfonate betaine and pentaerythritol stearate to the dispersion, stir evenly, separate the solid, and dry the solid to obtain the modified silicon carbide; the weight ratio of the dispersion to lauramidopropyl hydroxysulfonate betaine and pentaerythritol stearate is 100:7:13.

[0050] Preparation method: Polylactic acid resin, poly(butylene adipate / terephthalate), calcium carbonate, polyethylene glycol and modified silicon carbide are mixed evenly, and then extruded and granulated by a twin-screw extruder to obtain the high-strength biodegradable polylactic acid composite material.

[0051] Comparative Example 1: Preparation of High-Strength Biodegradable Polylactic Acid Composite Material

[0052] Raw material composition by weight: 80 parts polylactic acid resin; 40 parts polybutylene adipate / terephthalate; 0.3 parts calcium carbonate; 3 parts polyethylene glycol 4000; 15 parts modified silicon carbide;

[0053] The modified silicon carbide is prepared by the following method:

[0054] (1) Take silicon carbide and irradiate it with an electron accelerator. After the irradiation is completed, silicon carbide after irradiation treatment is obtained. The irradiation time is 15 min and the irradiation dose is 50 kGy.

[0055] (2) The irradiated silicon carbide is added to an ethanol aqueous solution and stirred evenly to obtain a dispersion; the ethanol aqueous solution is an ethanol aqueous solution with an ethanol volume fraction of 60%; the weight ratio of the irradiated silicon carbide to the ethanol aqueous solution is 1:5.

[0056] (3) Add lauramidopropyl hydroxysulfonate to the dispersion, stir evenly, separate the solid, and dry the solid to obtain the modified silicon carbide; the weight ratio of the dispersion to lauramidopropyl hydroxysulfonate is 100:20.

[0057] Preparation method: Polylactic acid resin, poly(butylene adipate / terephthalate), calcium carbonate, polyethylene glycol and modified silicon carbide are mixed evenly, and then extruded and granulated by a twin-screw extruder to obtain the high-strength biodegradable polylactic acid composite material.

[0058] Comparative Example 2: Preparation of High-Strength Biodegradable Polylactic Acid Composite Material

[0059] Raw material composition by weight: 80 parts polylactic acid resin; 40 parts polybutylene adipate / terephthalate; 0.3 parts calcium carbonate; 3 parts polyethylene glycol 4000; 15 parts modified silicon carbide;

[0060] The modified silicon carbide is prepared by the following method:

[0061] (1) Take silicon carbide and irradiate it with an electron accelerator. After the irradiation is completed, silicon carbide after irradiation treatment is obtained. The irradiation time is 15 min and the irradiation dose is 50 kGy.

[0062] (2) The irradiated silicon carbide is added to an ethanol aqueous solution and stirred evenly to obtain a dispersion; the ethanol aqueous solution is an ethanol aqueous solution with an ethanol volume fraction of 60%; the weight ratio of the irradiated silicon carbide to the ethanol aqueous solution is 1:5.

[0063] (3) Add pentaerythritol stearate to the dispersion, stir evenly, separate the solid, and dry the solid to obtain the modified silicon carbide; the weight ratio of the dispersion to pentaerythritol stearate is 100:20.

[0064] Preparation method: Polylactic acid resin, poly(butylene adipate / terephthalate), calcium carbonate, polyethylene glycol and modified silicon carbide are mixed evenly, and then extruded and granulated by a twin-screw extruder to obtain the high-strength biodegradable polylactic acid composite material.

[0065] Table 1. Tensile strength of high-strength biodegradable polylactic acid composites

[0066] Tensile strength The high-strength biodegradable polylactic acid composite material prepared in Example 1 81.2MPa The high-strength biodegradable polylactic acid composite material prepared in Example 2 54.6MPa The high-strength biodegradable polylactic acid composite material prepared in Example 3 71.7MPa High-strength biodegradable polylactic acid composite material prepared in Comparative Example 1 58.8MPa High-strength biodegradable polylactic acid composite material prepared in Comparative Example 2 62.0MPa

[0067] As can be seen from the experimental data in Table 1, the high-strength biodegradable polylactic acid composite material prepared in Example 1 has a tensile strength of 81.2 MPa, which indicates that the polylactic acid composite material prepared by the present invention has high tensile strength.

[0068] As can be seen from the experimental data in Table 1, the tensile strength of the high-strength biodegradable polylactic acid composite material prepared in Example 2 is significantly reduced compared with that in Example 1. This indicates that the addition of silicon carbide to the polylactic acid composite material of the present invention significantly reduces the tensile strength of the polylactic acid composite material.

[0069] As can be seen from the experimental data in Table 1, the tensile strength of the high-strength biodegradable polylactic acid composite material prepared in Example 3 was significantly improved compared with that in Example 2, reaching 71.7 MPa. This indicates that adding modified silicon carbide prepared by the method described in this invention to the polylactic acid composite material can significantly improve the tensile strength of the polylactic acid composite material compared with the polylactic acid composite material prepared by adding silicon carbide.

[0070] As can be seen from the experimental data in Table 1, the tensile strength of the high-strength biodegradable polylactic acid composites prepared in Comparative Examples 1 and 2 was not significantly improved compared with that in Example 2. This indicates that in polylactic acid composites, modified silicon carbide obtained by modifying both lauramidopropyl hydroxysulfonate and pentaerythritol stearate must be added to significantly improve the tensile strength of polylactic acid composites. However, adding only modified silicon carbide obtained by modifying only lauramidopropyl hydroxysulfonate or only pentaerythritol stearate cannot significantly improve the tensile strength of polylactic acid composites.

Claims

1. A high-strength degradable polylactic acid composite, characterized by, The raw material components include the following by weight: Polylactic acid resin 80 parts; polybutylene adipate terephthalate 40 parts; calcium carbonate 0.3 parts; polyethylene glycol 3 parts; silicon carbide 15 parts; The silicon carbide is modified silicon carbide; The modified silicon carbide is prepared by the following method: (1) Take silicon carbide, irradiate with an electron accelerator, and obtain irradiated silicon carbide after irradiation; (2) Add the irradiated silicon carbide into an ethanol aqueous solution, stir to obtain a dispersion; (3) Add lauryl amidopropyl hydroxysultaine and pentaerythritol stearate into the dispersion, stir to separate the solid, dry the solid to obtain the modified silicon carbide; The irradiation time in step (1) is 10-20 min, and the irradiation dose is 40-60 kGy; The ethanol aqueous solution in step (1) is an ethanol aqueous solution with an ethanol volume fraction of 50-70%; The weight ratio of the irradiated silicon carbide to the ethanol aqueous solution in step (1) is 1:4-6; The weight ratio of the dispersion to lauryl amidopropyl hydroxysultaine and pentaerythritol stearate in step (3) is 100:5-10:10-15.

2. The high-strength degradable polylactic acid composite of claim 1, wherein, The irradiation time in step (1) is 15 min, and the irradiation dose is 50 kGy.

3. The high-strength degradable polylactic acid composite of claim 1, wherein, The ethanol aqueous solution in step (1) is an ethanol aqueous solution with an ethanol volume fraction of 60%.

4. The high-strength degradable polylactic acid composite of claim 1, wherein, The weight ratio of the irradiated silicon carbide to the ethanol aqueous solution in step (1) is 1:

5.

5. The high-strength degradable polylactic acid composite of claim 1, wherein, The weight ratio of the dispersion to lauryl amidopropyl hydroxysultaine and pentaerythritol stearate in step (3) is 100:7:

13.

6. Use of the high-strength degradable polylactic acid composite material of any one of claims 1-5 in the preparation of packaging materials.