Biodegradable polyester composite material and preparation method thereof

Abstract

The invention relates to a biodegradable polyester composite material and a preparation method thereof, and mainly solves the problems in the prior art that the mechanical strength of the material is low, and the biodegradation rate is 1t; and 90% of the problems are solved. The biodegradable polyester composite material is prepared from the following components in parts by weight: (i) 50 to 79 parts of biodegradable polyester; (ii) 1 to 30 parts of thermoplastic starch; (iii) 1 to 35 parts of a biomass material; (iii) 5 to 15 parts of an interfacial compatibilizer; (iv) 0.1 to 10 parts of a flow promoter; (v) 0.5 to 2.5 parts of an antioxidant; (vi) 0.5 to 2.5 parts of a UV absorbent; wherein the biomass material comprises a fibrous biomass material and a granular biomass material; the fibrous biomass material is selected from at least one of lignin, cellulose and straw; the granular biomass material is selected from at least one of fruit peels, fruit shells and seed shells. According to the technical scheme, the problems are well solved, industrial production can be achieved, and the method can be used for packaging articles such as agricultural products and disposable tableware.

Description

Technical Field

[0001] The invention belongs to the field of biodegradable materials and relates to a biodegradable polyester composite material and a preparation method thereof. Background Art

[0002] Since its advent, plastic materials have been widely used in all aspects of people's lives. However, since it is not easy to degrade in the natural environment, it has brought great harm to the ecological environment, organisms and even humans. White pollution has become an important problem that plagues the world. In addition, plastic materials are refined and synthesized from petroleum, and the huge consumption and demand also bring energy crises. Therefore, with the continuous enhancement of environmental protection policies and people's environmental awareness, seeking alternative products to petroleum-based raw materials, developing bio-based polymer monomers and biodegradable plastic materials have received more and more attention and attention.

[0003] At present, the market for biodegradable materials is booming and demand continues to grow. Related material technologies are also constantly innovating and improving. Chinese patent CN115626977 discloses a method for synthesizing aliphatic-aromatic copolyesters through imine groups and intermolecular crosslinking. Chinese patent CN118290847 reports a preparation method for biodegradable polyester modified with ultrafine walnut shell powder with a particle size of 1000~1500 mesh, but does not provide data on the performance of the material. Chinese patent CN118185253 discloses a technology for preparing biodegradable film materials using lignin materials, but does not disclose the level of biodegradation rate. In the future, with the advancement of technology and the reduction of costs, the application field of biodegradable materials will be further expanded. The development of environmentally friendly materials and process technologies will be particularly important for production companies. Summary of the invention

[0004] The present invention aims to solve the problems of low mechanical strength and biodegradation rate of less than 90% in the prior art, and provides a biodegradable polyester composite material that meets the application requirements of packaging, agricultural products, disposable tableware and the like.

[0005] In order to solve the above technical problems, the present invention provides a biodegradable polyester composite material, which comprises the following components by weight: (i) 50 to 79 parts of a biodegradable polyester; (ii) 1 to 30 parts of thermoplastic starch; (iii) 1 to 35 portions of biomass material; (iii) 5 to 15 parts of an interfacial compatibilizer; (iv) 0.1 to 10 parts of a flow aid; (v) 0.5 to 2.5 parts of an antioxidant; (vi) 0.5 to 2.5 parts of a UV absorber; Among them, the biomass materials include fibrous and granular biomass materials; the fibrous biomass materials are selected from at least one of lignin, cellulose, and straw; the aspect ratio of the fibrous biomass materials is 5 to 50; the granular biomass materials are selected from at least one of fruit peels, fruit shells, and seed shells; the particle size of the granular biomass materials is 500 to 5000 mesh.

[0006] In a preferred technical solution, the biodegradable polyester is selected from at least one of poly(butylene succinate-co-terephthalate), poly(butylene adipate-co-terephthalate), poly(butylene malate-co-terephthalate), poly(butylene succinate-co-malate-co-terephthalate), poly(butylene adipate-co-malate-co-terephthalate), and poly(butylene succinate-co-adipate-co-malate-co-terephthalate); The proportion of terephthalic acid in the biodegradable polyester does not exceed 50% of the total molar amount of diacid monomers, preferably not exceeding 35%; The intrinsic viscosity of the biodegradable polyester is 0.60 to 0.85 dL / g, preferably 0.65 to 0.80 dL / g.

[0007] In a preferred technical solution, the thermoplastic starch comprises 85 to 95 parts by weight of starch and 5 to 15 parts by weight of a plasticizer; The starch is selected from at least one of corn starch, sweet potato starch, and wheat starch; The plasticizer is selected from at least one of glycerol, diethylene glycol, and water, preferably a combination of glycerol and water; The thermoplastic starch is prepared by the following method: Pre-mix the starch and the plasticizer, introduce them into a twin-screw extruder, and obtain the thermoplastic starch through in-situ plasticization, melting, extrusion, and pelletization; The plasticization temperature is 110 to 150 °C, preferably 120 to 135 °C; The rotation speed of the twin-screw extruder is 150 to 800 revolutions per minute, preferably 300 to 600 revolutions per minute.

[0008] In a preferred technical solution, the interfacial compatibilizer is selected from at least one of isocyanatopropyltriethoxysilane, epoxy polyacrylate, and poly(ethylene-co-glycidyl methacrylate).

[0009] In a preferred technical solution, the flow aid is selected from at least one of the commercial brands SR-520 and ATL95.

[0010] In a preferred technical solution, the antioxidant is selected from at least one of the commercial brands 1010, 1076, and 168.

[0011] In a preferred technical solution, the UV absorber is selected from at least one of benzotriazoles, hydroxybenzoates, and their derivatives.

[0012] Meanwhile, the present invention also provides a method for preparing a biodegradable polyester composite material, which is simple and easy to implement and is easy to achieve industrial preparation.

[0013] In a preferred technical solution, the method for preparing the biodegradable polyester composite material includes the following steps: Mix the biodegradable polyester, thermoplastic starch, biomass material, interfacial compatibilizer, flow aid, antioxidant, and UV absorber, and introduce them into a twin-screw extruder for melting, kneading, extrusion, and pelletizing to obtain the biodegradable polyester composite material.

[0014] In a preferred technical solution, the melting temperature is 150 - 200 °C; the rotation speed of the extruder is 200 - 800 revolutions per minute.

[0015] In a preferred technical solution, the tensile fracture strength of the biodegradable polyester composite material is 25 MPa or more, and the degradation rate is 92% or more after composting treatment at 60 °C and 55% humidity for 60 days.

[0016] Advantages of the method of the present patent invention: (i) Using fibrous and granular biomass materials to form a biodegradable polyester composite material with biodegradable polyester and thermoplastic starch, without petroleum-based raw materials, providing a technical basis for energy conservation, emission reduction, and green development.

[0017] (ii) Using an efficient plasticizer to successfully plasticize starch with poor processing performance to obtain thermoplastic starch, which is introduced into the biodegradable material to achieve cost reduction and efficiency improvement.

[0018] (iii) Using flow aids, interfacial compatibilizers, etc., to endow the biodegradable polyester composite material with excellent processing and mechanical properties, achieving good technical effects.

[0019] The performance of the composition in the method of the present invention is measured by the following method: Tensile fracture strength / elongation: Measured according to the ISO 527-3 standard, with a thickness of 10 microns.

[0020] Biodegradation rate: According to the GB / T 19277 standard, composting treatment is carried out at 60 °C and 55% humidity for 60 days.

[0021] The present invention is further illustrated below through specific examples. Detailed implementation mode

[0022]

Example 1

[0023] (2)75 kg of poly(adipic acid-co-terephthalic acid) butylene ester (molar ratio of adipic acid / terephthalic acid 65 / 35, intrinsic viscosity 0.75 dL / g), 19 kg of thermoplastic starch A, 5 kg of straw (length-diameter ratio 40), 10 kg of peach pit powder (particle size 1250 mesh), 1 kg of isocyanate propyltriethoxysilane, 6 kg of poly(ethylene-co-glycidyl methacrylate), 2.5 kg of flow aid SR-520, 0.75 kg of antioxidant 1076, and 0.85 kg of hydroxybenzoate were fully mixed in a high-speed mixer and introduced into a twin-screw extruder. At a melting temperature of 195 °C and a speed of 500 revolutions per minute, melting, kneading, extrusion, and granulation were carried out to obtain a biodegradable polyester composite material. After calendaring at 200 °C and cutting into standard samples for testing and evaluation, its performance is shown in Table 1.

[0024]

Example 2

[0025]

Example 3

[0026]

Example 4

[0027]

Comparative Example 1

[0028] Table 1 As can be seen from Table 1, through the combination of thermoplastic starch, straw and peach kernel powder, together with poly(butylene adipate-co-terephthalate) and other functional additives, a biodegradable polyester composite material with a tensile fracture strength of more than 25 MPa, an elongation at break of more than 100%, and a biodegradation rate of more than 92.0% can be prepared.

[0029]

Example 5

[0030] (2)25 kg of poly(butylene succinate-co-terephthalate) (molar ratio of succinic acid / terephthalic acid 50 / 50, intrinsic viscosity 0.72 dL / g), 35 kg of poly(butylene succinate-co-adipate-co-malate-co-terephthalate), 30 kg of thermoplastic starch B, 8 kg of lignin (aspect ratio 25), 2 kg of walnut shell powder (particle size 2000 mesh), 4 kg of poly(ethylene-co-glycidyl methacrylate), 6 kg of flow aid ATL95, 1 kg of antioxidant 1076, 0.25 kg of 168, and 1.5 kg of benzotriazole were fully mixed in a high-speed mixer and then introduced into a twin-screw extruder. At a melting temperature of 190 °C and a speed of 400 rpm, melting, kneading, extrusion and granulation were carried out to obtain a biodegradable polyester composite material. After hot pressing at 190 °C and cutting into standard samples for testing and evaluation, its performance is shown in Table 2.

[0031]

Example 6

[0032]

Example 7

[0033]

Example 8

[0034]

Comparative Example 2

[0035]

Comparative Example 3

[0036]

Comparative Example 4

[0037] Table 2 As can be seen from Table 2, Examples 5 to 8 adopt a combination of biodegradable polyester, thermoplastic starch, lignin, and walnut shell powder. Compared with Comparative Examples 2 and 3, the composite materials prepared by the method of the present invention simultaneously have high tensile fracture strength (>25 MPa) and biodegradation rate (>92%), and are far superior to the performance of polybutylene terephthalate composite materials, reflecting the advantages of the protection scope of the present invention.

Claims

1. A biodegradable polyester composite material, characterized in that: By weight, it includes the following components: (i) 50 to 79 parts of a biodegradable polyester; (ii) 1 to 30 parts of thermoplastic starch; (iii) 1 to 35 portions of biomass material; (iii) 5 to 15 parts of an interfacial compatibilizer; (iv) 0.1 to 10 parts of a flow aid; (v) 0.5 to 2.5 parts of an antioxidant; (vi) 0.5 to 2.5 parts of a UV absorber; Among them, the biomass material includes fibrous and granular biomass materials; the fibrous biomass material is selected from at least one of lignin, cellulose, and straw; the aspect ratio of the fibrous biomass material is 5~50; the granular biomass material is selected from at least one of fruit peel, fruit shell, and seed shell; the particle size of the granular biomass material is 500~5000 mesh.

2. The biodegradable polyester composite material according to claim 1, characterized in that: The biodegradable polyester is selected from at least one of poly(butylene succinate-co-terephthalate), poly(butylene adipate-co-terephthalate), poly(butylene malate-co-terephthalate), poly(butylene succinate-co-malate-co-terephthalate), poly(butylene adipate-co-malate-co-terephthalate), and poly(butylene succinate-co-butylene adipate-co-malate-co-terephthalate); The proportion of terephthalic acid in the total molar amount of diacid monomers in the biodegradable polyester does not exceed 50%; The intrinsic viscosity of the biodegradable polyester is 0.60-0.85 dl / g.

3. The biodegradable polyester composite material according to claim 1, characterized in that: The thermoplastic starch comprises 85-95 parts by weight of starch and 5-15 parts by weight of a plasticizer; The starch is selected from at least one of corn starch, sweet potato starch and wheat starch; The plasticizer is selected from at least one of glycerol, diethylene glycol and water; The thermoplastic starch is prepared by the following method: The starch and the plasticizer are premixed and introduced into a twin-screw extruder, and then plasticized, melted, extruded and granulated in situ to obtain thermoplastic starch; The plasticizing temperature is 110-150°C; The rotation speed of the twin-screw extruder is 150-800 rpm.

4. The biodegradable polyester composite material according to claim 1, characterized in that: The interfacial compatibilizer is selected from at least one of isocyanate propyl triethoxy silane, epoxy polyacrylate, and poly(ethylene-co-glycidyl methacrylate).

5. The biodegradable polyester composite material according to claim 1, characterized in that: The flow aid is selected from at least one of the trade names SR-520 and ATL95.

6. The biodegradable polyester composite material according to claim 1, characterized in that: The antioxidant is selected from at least one of the trade names 1010, 1076, and 168.

7. The biodegradable polyester composite material according to claim 1, characterized in that: The UV absorber is at least one selected from benzotriazole, hydroxybenzoic acid ester and their derivatives.

8. The biodegradable polyester composite material according to any one of claims 1 to 7, characterized in that: The tensile breaking strength of the biodegradable polyester composite material is above 25 MPa, and the degradation rate is above 92% after composting at 60° C. and 55% humidity for 60 days.

9. The method for preparing the biodegradable polyester composite material according to any one of claims 1 to 8, characterized in that: The following steps are involved: The biodegradable polyester, thermoplastic starch, biomass material, interfacial compatibilizer, flow aid, antioxidant and UV absorber are mixed and introduced into a twin-screw extruder for melting, kneading, extrusion and granulation to obtain a biodegradable polyester composite material.

10. The method for preparing the biodegradable polyester composite material according to claim 9, characterized in that: The melting temperature is 150-200° C.; the rotation speed of the extruder is 200-800 rpm.

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