Foaming-grade biodegradable polyester material and preparation method thereof

Abstract

The invention discloses a foaming-grade biodegradable polyester material, which is characterized by being prepared from the following raw materials by weight: 91.90-99.78% of biodegradable polyester; 0.01 to 0.1 percent of organic peroxide; 0.10% to 3.00% of o-diallyl bisphenol A diglycidyl ether; 0.01 to 2.00% of a lubricant; and 0.10%-3.00% of a foam hole nucleating agent. The invention also provides a preparation method of the foaming-grade biodegradable polyester material, and the method has the advantages of continuous production and low processing cost, and can meet the requirements of large-scale production. The foaming-grade biodegradable polyester material has excellent foamability and high melt strength, the use amount of organic peroxide is extremely low, and the foaming-grade biodegradable polyester material conforms to food safety certification.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and particularly relates to a foaming-grade biodegradable polyester material and a preparation method thereof. Background Art

[0002] In recent years, traditional non-degradable foam materials have become one of the main sources of "white pollution" because foam materials are light in weight and difficult to recycle, resulting in high recycling costs. Eventually, the vast majority of foam products are discarded, landfilled or incinerated after use. It can be seen that developing biodegradable foam materials is one of the effective means to solve "white pollution" in the field of foam products. Against this background, biodegradable foam materials have received increasing attention from the business community, academia and society.

[0003] Existing biodegradable polyester materials all have a linear molecular structure, so that their melt strength is low and it is difficult to meet the production requirements of the foaming molding process. It can be seen that improving the melt strength of polyester materials is one of the key technologies for preparing biodegradable polyester foam products. Introducing a long branched-chain structure into the biodegradable polyester molecular chain can effectively improve its melt strength. Among them, preparing long branched-chain polyester by reaction technology has the advantages of continuous production, high production efficiency and low processing cost, and is most suitable for large-scale industrial production. At present, a large number of literatures and patents have reported the preparation of long branched-chain polyester materials by inducing with organic peroxides to improve the melt strength of polyester materials. However, this technology for preparing long branched-chain polyester materials by inducing with organic peroxides has the problem of high consumption of organic peroxides, so that the long branched-chain polyester contains a large amount of irritating volatile substances formed by the decomposition of organic peroxides, which limits the application of long branched-chain polyester materials in the fields of products in contact with food and medicine. It can be seen that how to reduce the consumption of organic peroxides to ensure that the prepared long branched-chain polyester fully meets food and medicine safety certifications is of great significance for the development of biodegradable polyester foam products. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a foaming-grade biodegradable polyester material, which has excellent foamability and high melt strength, and the consumption of organic peroxides is extremely low, meeting food safety certifications. The adopted technical solution is as follows: A foaming-grade biodegradable polyester material, characterized in that it is made of raw materials with the following weight ratios: biodegradable polyester 91.90 - 99.78%; organic peroxide 0.01 - 0.1%; o-diallylbisphenol A diglycidyl ether 0.10 - 3.00%; lubricant 0.01 - 2.00%; cell nucleating agent 0.10 - 3.00%.

[0005] Preferably, the above-mentioned foaming-grade biodegradable polyester material is made from raw materials with the following weight ratios: biodegradable polyester 94.45 - 99.18%; organic peroxide 0.02 - 0.05%; o-diallylbisphenol A diglycidyl ether 0.20 - 2.00%; lubricant 0.10 - 1.50%; cell nucleating agent 0.50 - 2.00%.

[0006] Preferably, the above-mentioned biodegradable polyester is one or a combination of more than one of polylactic acid, polyglycolide, polybutylene succinate, polybutylene succinate adipate, polybutylene terephthalate-co-butylene succinate, polybutylene terephthalate adipate, polyhydroxybutyrate, and poly(3-hydroxybutyrate-co-3-hydroxyvalerate). The English abbreviation of the above-mentioned polylactic acid is PLA, also known as poly(lactic acid). The English abbreviation of the above-mentioned polyglycolide is PGA. The English abbreviation of the above-mentioned polybutylene succinate is PBS. The English abbreviation of the above-mentioned polybutylene succinate adipate is PBSA. The English abbreviation of the above-mentioned polybutylene terephthalate-co-butylene succinate is PBST. The English abbreviation of the above-mentioned polybutylene terephthalate adipate is PBAT. The English abbreviation of the above-mentioned polyhydroxybutyrate is PHB. The English abbreviation of the above-mentioned poly(3-hydroxybutyrate-co-3-hydroxyvalerate) is PHBV.

[0007] Preferably, the above-mentioned organic peroxide is one or a combination of more than one of alkyl peroxide, aryl peroxide, diacyl peroxide, peroxyketal, perester, peroxycarbonate, and cyclic peroxide. More preferably, the above-mentioned organic peroxide is one or a combination of perester and peroxycarbonate. Even more preferably, the above-mentioned organic peroxide is a mixture of perester and peroxycarbonate.

[0008] Even more preferably, the above-mentioned organic peroxide is one or a combination of more than one of tert-butyl peroxybenzoate, tert-butyl peroxy-2-ethylhexanoate, tert-butyl peroxy-3,5,5-trimethylhexanoate, n-butyl-4,4-bis(tert-butylperoxy)valerate, ethyl-3,3-bis(tert-butylperoxy)butyrate, tert-butyl peroxyisopropyl carbonate, tert-butyl peroxy-2-ethylhexyl carbonate, tert-amyl peroxy-2-ethylhexyl carbonate, di(2-ethylhexyl) peroxydicarbonate, di-(tetradecyl) peroxydicarbonate, di-(hexadecyl) peroxydicarbonate, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxynonane.

[0009] Preferably, the purity of the above-mentioned diallyl bisphenol A diglycidyl ether is greater than 97 wt%. Using high-purity diallyl bisphenol A diglycidyl ether can reduce the influence of impurities, improve the biodegradability of the polyester material, enable the polyester material to decompose and degrade more quickly and effectively in the environment, and reduce environmental pollution. As a bifunctional additive, on the one hand, the organic peroxide can induce the diallyl bisphenol A diglycidyl ether to undergo a free radical grafting reaction with the biodegradable polyester through its allyl group, thereby introducing a long branched chain structure into the molecular chain of the biodegradable polyester; on the other hand, the diallyl bisphenol A diglycidyl ether can chemically react with the terminal carboxyl group of the biodegradable polyester through its epoxy bond, thereby introducing a new long branched chain structure into the molecular chain of the biodegradable polyester.

[0010] Preferably, the above-mentioned lubricant is one or a combination of ethylene bisstearamide, ethylene bis-12-hydroxystearamide, pentaerythritol tetrastearate, pentaerythritol tristearate, pentaerythritol distearate, pentaerythritol monostearate, glycerol tristearate, glycerol distearate, glycerol monostearate, erucamide and oleamide.

[0011] Preferably, the above-mentioned cell nucleating agent is one or a combination of calcium carbonate powder, talc powder, nano-silica powder and montmorillonite powder. More preferably, the mesh number of the above-mentioned cell nucleating agent is 2000-5000 mesh. More preferably, the above-mentioned cell nucleating agent is talc powder with a mesh number of 2000-5000 mesh.

[0012] The present invention also provides a preparation method of the above-mentioned foaming grade biodegradable polyester material, which is characterized by including the following steps: (1) By weight, prepare the following raw materials: 91.90-99.78% of biodegradable polyester, 0.01-0.1% of organic peroxide, 0.10-3.00% of diallyl bisphenol A diglycidyl ether, 0.01-2.00% of lubricant, 0.10-3.00% of cell nucleating agent; (2) Dry the biodegradable polyester at 45°C - 120°C for 60 min - 120 min to make the moisture content of the biodegradable polyester lower than 200 ppm, and cool it to 10°C - 30°C; (3) Add the organic peroxide and diallyl bisphenol A diglycidyl ether to the biodegradable polyester and mix evenly to obtain a mixed material; (4) Dry the cell nucleating agent at 100°C - 150°C for 60 min - 120 min to make its moisture content lower than 200 ppm, and cool it to 10°C - 30°C; (5) Add the lubricant and the cell nucleating agent obtained in step (4) to the mixed material obtained in step (3), and mix evenly to obtain a second mixed material; (6) Melt-extrude the second mixed material through a twin-screw extruder to obtain a foaming-grade biodegradable polyester material.

[0013] After drying the materials in the above steps (2) and (4), they need to be cooled to 10°C - 30°C to prevent premature decomposition of the peroxide due to high temperature.

[0014] Preferably, the length-diameter ratio of the screw of the twin-screw extruder in step (6) above is 40:1 - 52:1.

[0015] Preferably, the temperature of the twin-screw extruder in step (6) above is 150°C - 220°C.

[0016] Preferably, in step (6) above, the second mixed material is melted and extruded into a strip through a twin-screw extruder, and the strip is cooled and pelletized to obtain a granular foaming-grade biodegradable polyester material.

[0017] Add the obtained foaming-grade biodegradable polyester material to an extrusion foaming production line, use supercritical carbon dioxide as a foaming agent, and perform melt blending extrusion to finally obtain a foaming-grade biodegradable polyester sheet.

[0018] The foaming-grade biodegradable polyester material of the present invention has the following advantages: (1) As shown in the following chemical reaction general formula, the present invention uses a trace amount of organic peroxide to cooperate with diallyl bisphenol A diglycidyl ether to introduce a long branched chain structure into the biodegradable polyester molecular chain, thereby endowing the biodegradable polyester with the characteristics of high melt strength and excellent foaming performance. On the one hand, the organic peroxide can induce diallyl bisphenol A diglycidyl ether to undergo a free radical grafting reaction with the biodegradable polyester through its allyl group, thereby introducing a long branched chain structure into the molecular chain of the foaming-grade biodegradable polyester material; on the other hand, diallyl bisphenol A diglycidyl ether can undergo a chemical reaction with the terminal carboxyl group of the biodegradable polyester through its epoxy bond, thereby introducing a new long branched chain structure into the molecular chain of the foaming-grade biodegradable polyester material. Under the synergistic effect of the above two aspects, the entanglement between the molecular chains of the biodegradable polyester is greatly improved, thereby endowing the foaming-grade biodegradable polyester material with extremely high melt strength and extremely excellent foaming performance. In addition, the dosage of the organic peroxide in the present invention is extremely low, and only a very small amount of volatile substances are decomposed, which ensures that the modified polyester contains very few irritating volatile substances, making this foaming-grade biodegradable polyester material fully comply with food safety certification and guarantee the safety and health of consumers.

[0019]

[0020] (2) The present invention uses a twin-screw reactive extrusion technology to prepare a foaming-grade biodegradable polyester material, which has the advantages of continuous production, high production efficiency, and low processing cost, and can meet the requirements of large-scale production.

[0021] (3) The foaming-grade biodegradable polyester material in the present invention can be applied to traditional foaming molding methods such as autoclave foaming, compression molding foaming, extrusion foaming, and injection molding foaming, which is of great significance for expanding the application fields of biodegradable polyesters. Specific Embodiments

[0022] Example 1

[0023] In this example, the preparation method of this foaming-grade biodegradable polyester material successively includes the following steps: (1) By weight, the following raw materials are equipped: 97.98% of biodegradable polyester (all are polybutylene succinate), 0.02% of organic peroxide (all are tert-butyl peroxy-2-ethylhexanoate), 0.70% of diallyl bisphenol A diglycidyl ether, 1.00% of cell nucleating agent (all are talc powder with a mesh number of 3000), and 0.30% of glycerol monostearate; (2) The polybutylene succinate is dried at 90 °C for 90 min to make its moisture content lower than 200 ppm, and then cooled to 25 °C; (3) The organic peroxide and diallyl bisphenol A diglycidyl ether are added to the polybutylene succinate and mixed evenly to obtain a mixed material; (4) The talc powder is dried at 110 °C for 120 min to make its moisture content lower than 200 ppm, and then cooled to 30 °C; (5) The glycerol monostearate and the talc powder obtained in step (4) are added to the mixed material obtained in step (3) and mixed evenly to obtain a second mixed material; (6) The second mixed material is melted and extruded into a strip by a twin-screw extruder, and the extruded strip is cooled and pelletized to obtain a granular foaming-grade biodegradable polyester material.

[0024] The length-diameter ratio of the screw of the twin-screw extruder in step (6) above is 48:1.

[0025] Preferably, the temperature of the twin-screw extruder in step (6) above is 160 °C - 180 °C.

[0026] The obtained foaming-grade biodegradable polyester material is dried at 90 °C for 120 min, and then added to an extrusion foaming production line, and supercritical carbon dioxide is used as a foaming agent for melt extrusion foaming to finally obtain a foamed sheet.

[0027] Example 2

[0028] In this example, the preparation method of this foaming grade biodegradable polyester material successively includes the following steps: (1) By weight, the following raw materials are equipped: 96.95% of biodegradable polyester (all are polylactic acid), 0.05% of organic peroxide (all are tert-butyl peroxybenzoate), 0.50% of diallyl bisphenol A diglycidyl ether, 1.50% of cell nucleating agent (all are talcum powder with a mesh number of 5000), and 1.00% of ethylene bis-12-hydroxystearamide; (2) The polylactic acid is dried at 100 °C for 120 min to make the water content of the polylactic acid lower than 200 ppm, and then cooled to 20 °C; (3) The organic peroxide and diallyl bisphenol A diglycidyl ether are added to the polylactic acid and mixed evenly to obtain a mixed material; (4) The talcum powder is dried at 120 °C for 100 min to make its water content lower than 200 ppm, and then cooled to 20 °C; (5) Ethylene bis-12-hydroxystearamide and the talcum powder obtained in step (4) are added to the mixed material obtained in step (3) and mixed evenly to obtain a second mixed material; (6) The second mixed material is melted and extruded into a strip by a twin-screw extruder, and the extruded strip is cooled and pelletized to obtain a granular foaming grade biodegradable polyester material.

[0029] The length-diameter ratio of the screw of the twin-screw extruder in the above step (6) is 44:1.

[0030] Preferably, the temperature of the twin-screw extruder in the above step (6) is 180 °C - 200 °C.

[0031] The obtained foaming grade biodegradable polyester material is dried at 100 °C for 120 min, then added to an extrusion foaming production line, and supercritical carbon dioxide is used as a foaming agent for melt extrusion foaming to finally obtain a foamed sheet.

[0032] Example 3

[0033] In this example, the preparation method of this foaming grade biodegradable polyester material successively includes the following steps: (1) By weight, the following raw materials are equipped: 98.23% of biodegradable polyester (all are poly(3-hydroxybutyrate-co-3-hydroxyvalerate)), 0.07% of organic peroxide (all are tert-amyl peroxy-2-ethylhexyl carbonate), 0.70% of diallyl bisphenol A diglycidyl ether, 0.50% of cell nucleating agent (all are nano-silica powder), and 0.50% of pentaerythritol tetrastearate; (2) Dry poly(3-hydroxybutyrate-co-3-hydroxyvalerate) at 95 °C for 80 min to make its moisture content lower than 200 ppm, and then cool it to 25 °C; (3) Add an organic peroxide and diallyl bisphenol A diglycidyl ether to poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and mix them evenly to obtain a mixed material; (4) Dry nano-silica powder at 100 °C for 100 min to make its moisture content lower than 200 ppm, and then cool it to 20 °C; (5) Add pentaerythritol tetrastearate and the nano-silica powder obtained in step (4) to the mixed material obtained in step (3) and mix them evenly; (6) Melt and extrude the mixed material through a twin-screw extruder to obtain a strip, and cool and pelletize the extruded strip to obtain a granular foaming-grade biodegradable polyester material.

[0034] The length-diameter ratio of the screw of the twin-screw extruder in the above step (6) is 40:1.

[0035] Preferably, the temperature of the twin-screw extruder in the above step (6) is 185 °C - 205 °C.

[0036] Dry the obtained foaming-grade biodegradable polyester material at 95 °C for 120 min, then add it to an extrusion foaming production line, use supercritical carbon dioxide as a foaming agent, and carry out melt extrusion foaming to finally obtain a foamed sheet.

[0037] Example 4

[0038] In this example, the preparation method of this foaming-grade biodegradable polyester material successively includes the following steps: (1) Weigh and prepare the following raw materials by weight: 96.90% biodegradable polyester (all polybutylene adipate terephthalate), 0.10% organic peroxide (including 0.05% tert-butyl peroxybenzoate and 0.05% tert-amyl peroxy-2-ethylhexyl carbonate), 1.50% diallyl bisphenol A diglycidyl ether, 1.00% cell nucleating agent (all calcium carbonate powder with a mesh number of 5000), 0.50% erucamide; (2) Dry polybutylene adipate terephthalate at 80 °C for 120 min to make its moisture content lower than 200 ppm, and then cool it to 20 °C; (3) Add an organic peroxide and diallyl bisphenol A diglycidyl ether to polybutylene adipate terephthalate and mix them evenly to obtain a mixed material; (4) Dry the calcium carbonate powder at 120 °C for 90 min to make its moisture content less than 200 ppm, and then cool it to 30 °C; (5) Add erucamide and the calcium carbonate powder obtained in step (4) to the mixed material obtained in step (3), and mix them evenly; (6) Melt and extrude the mixed material through a twin-screw extruder to obtain a strip. Cool and pelletize the extruded strip to obtain a granular foaming-grade biodegradable polyester material.

[0039] The length-diameter ratio of the screw of the twin-screw extruder in step (6) above is 44:1.

[0040] Preferably, the temperature of the twin-screw extruder in step (6) above is 160 °C - 180 °C.

[0041] Dry the obtained foaming-grade biodegradable polyester material at 80 °C for 120 min, then add it to an extrusion foaming production line, use supercritical carbon dioxide as a foaming agent, and perform melt extrusion foaming to finally obtain a foamed sheet.

[0042] Comparative Example 1 In this comparative example, it is pure polybutylene succinate (i.e., pure PBS), pure polylactic acid (i.e., pure PLA), pure poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (i.e., pure PHBV), and pure poly(butylene adipate-co-terephthalate) (i.e., pure PBAT).

[0043] Dry the above polyester materials at 90 °C for 120 min respectively, then add them to an extrusion foaming production line, use supercritical carbon dioxide as a foaming agent, and perform melt extrusion foaming to finally obtain the corresponding foamed sheets.

[0044] Comparative Example 2 The difference between the preparation method of polybutylene succinate in this comparative example and that in Example 1 lies in: (1) By weight, prepare the following raw materials: 98.68% of polybutylene succinate, 0.02% of organic peroxide (both are tert-butyl peroxy-2-ethylhexanoate), 1.00% of cell nucleating agent (both are talc powder with a mesh number of 3000), and 0.30% of glycerol monostearate; (2) Dry the polybutylene succinate at 90 °C for 90 min to make its moisture content less than 200 ppm, and then cool it to 25 °C; (3) Add the organic peroxide to the polybutylene succinate and mix them evenly to obtain a mixed material; (4) Dry the talc powder at 110 °C for 120 min to make its moisture content less than 200 ppm, and then cool it to 30 °C; (5) Add glyceryl monostearate and the talcum powder obtained in step (4) to the mixed material obtained in step (3), and mix evenly. (6) Melt and extrude the mixed material through a twin-screw extruder to obtain a strip. Cool and pelletize the extruded strip to obtain granular foaming-grade modified polybutylene succinate.

[0045] Preferably, the length-diameter ratio of the screw of the twin-screw extruder in step (6) above is 48:1.

[0046] Preferably, the temperature of the twin-screw extruder in step (6) above is 160°C - 180°C.

[0047] Dry the obtained foaming-grade modified polybutylene succinate at 90°C for 120 min, then add it to an extrusion foaming production line, and use supercritical carbon dioxide as a foaming agent to carry out melt extrusion foaming to finally obtain a foamed sheet.

[0048] Comparative Example 3 The difference between the preparation method of polybutylene succinate in this comparative example and that in Example 1 lies in: (1) By weight, prepare the following raw materials: 98.00% of polybutylene succinate, 0.70% of diallylbisphenol A diglycidyl ether, 1.00% of cell nucleating agent (talcum powder with a mesh number of 3000), and 0.30% of glyceryl monostearate; (2) Dry the polybutylene succinate at 90°C for 90 min to make its moisture content less than 200 ppm, and cool it to 25°C; (3) Add diallylbisphenol A diglycidyl ether to the polybutylene succinate and mix evenly to obtain a mixed material; (4) Dry the talcum powder at 110°C for 120 min to make its moisture content less than 200 ppm, and cool it to 30°C; (5) Add glyceryl monostearate and the talcum powder obtained in step (4) to the mixed material obtained in step (3), and mix evenly; (6) Melt and extrude the mixed material through a twin-screw extruder to obtain a strip. Cool and pelletize the extruded strip to obtain granular foaming-grade modified polybutylene succinate.

[0049] Preferably, the length-diameter ratio of the screw of the twin-screw extruder in step (6) above is 48:1.

[0050] Preferably, the temperature of the twin-screw extruder in step (6) above is 160°C - 180°C.

[0051] The obtained foaming-grade modified poly(butylene succinate) was dried at 90 °C for 120 min, and then added to an extrusion foaming production line. Using supercritical carbon dioxide as a foaming agent, melt extrusion foaming was carried out to finally obtain a foamed sheet.

[0052] The properties of the foaming-grade biodegradable polyester materials in Examples 1-4 and the biodegradable polyesters obtained in Comparative Examples 1-4 were tested, where: (1)Melt strength (MS) test: The biodegradable polyesters obtained in Examples 1-4 and Comparative Examples 1-3 were dried in a vacuum oven at 80 °C for 12 hours. The melt strength of all materials was measured using a melt strength tester.

[0053] (2)Foaming ratio test: The foamed biodegradable polyester materials obtained in Examples 1-4 and Comparative Examples 1-3 were left standing indoors for one week. According to the volume exclusion theory, the density of each foam sample was measured using a densitometer. The foaming ratio was defined as the ratio of the initial density of the biodegradable polyester to the density of the foam sample.

[0054] The test results of the melt strength (MS) and foaming ratio of the foaming-grade biodegradable polyester materials in Examples 1-4 and the biodegradable polyesters obtained in Comparative Examples 1-3 are shown in Table 1 below.

[0055] Table 1: Melt strength (MS) and foaming ratio of the products in the examples

[0056] Table 2: Melt strength (MS) and foaming ratio of the products in the comparative examples

[0057] It can be seen from the above test results that: compared with Comparative Examples 1-3, Examples 1-4 have higher melt strength and foaming ratio. Among them, compared with the modified poly(butylene succinate) in Comparative Examples 2-3 (Comparative Example 2 only added organic peroxide, and Comparative Example 3 only added diallyl bisphenol A diglycidyl ether), the foaming-grade biodegradable polyester material prepared in Example 1 (adding both organic peroxide and diallyl bisphenol A diglycidyl ether in poly(butylene succinate)) has higher melt strength and foaming ratio, which is attributed to the efficient synergistic effect of organic peroxide and diallyl bisphenol A diglycidyl ether, which can more efficiently improve the melt strength and foaming performance of the foaming-grade biodegradable polyester material.

[0058] The technology disclosed in this patent is not limited to the preparation of foaming-grade biodegradable polyester materials, but also applicable to the preparation of other foaming-grade polymer materials, especially foaming-grade polyester polymer materials. The above embodiments are for the convenience of those of ordinary skill in the art to understand and apply the present invention. Those skilled in the art can make modifications to the above embodiments without creative efforts and apply them to other fields. Therefore, the present invention is not limited to the above embodiments, and the improvements and modifications made by those skilled in the art inspired by the present invention are within the protection scope of the present invention.

Claims

1. A foaming-grade biodegradable polyester material, characterized in that it is made from the following raw materials in the following weight ratios: biodegradable polyester 91.90 - 99.78%; organic peroxide 0.01 - 0.1%; diallyl bisphenol A diglycidyl ether 0.10 - 3.00%; lubricant 0.01 - 2.00%; cell nucleating agent 0.10 - 3.00%.

2. The foaming-grade biodegradable polyester material according to claim 1, characterized in that it is made from the following raw materials in the following weight ratios: biodegradable polyester 94.45 - 99.18%; organic peroxide 0.02 - 0.05%; diallyl bisphenol A diglycidyl ether 0.20 - 2.00%; lubricant 0.10 - 1.50%; cell nucleating agent 0.50 - 2.00%.

3. The foaming-grade biodegradable polyester material according to claim 1 or 2, characterized in that: the biodegradable polyester is one or a combination of more of polylactic acid, polyglycolide, polybutylene succinate, polybutylene succinate - adipate, poly(butylene terephthalate - co - succinate), poly(butylene terephthalate - adipate), polyhydroxybutyrate, and poly(3 - hydroxybutyrate - co - 3 - hydroxyvalerate).

4. The foaming-grade biodegradable polyester material according to claim 1 or 2, characterized in that: the organic peroxide is one or a combination of more of alkyl peroxide, aryl peroxide, diacyl peroxide, peroxide ketal, peroxide ester, peroxide carbonate, and cyclic peroxide.

5. The foaming-grade biodegradable polyester material according to claim 4, characterized in that: the organic peroxide is one or a combination of more of tert-butyl peroxybenzoate, tert-butyl peroxy-2-ethylhexanoate, tert-butyl peroxy-3,5,5-trimethylhexanoate, n-butyl-4,4-bis(tert-butylperoxy)valerate, ethyl-3,3-bis(tert-butylperoxy)butyrate, tert-butyl peroxyisopropyl carbonate, tert-butyl peroxy-2-ethylhexyl carbonate, tert-amyl peroxy-2-ethylhexyl carbonate, bis(2-ethylhexyl) peroxydicarbonate, bis(tetradecyl) peroxydicarbonate, bis(hexadecyl) peroxydicarbonate, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxynonane.

6. The foaming-grade biodegradable polyester material according to claim 1 or 2, characterized in that: the purity of the diallyl bisphenol A diglycidyl ether is greater than 97 wt%.

7. The foaming-grade biodegradable polyester material according to claim 1 or 2, characterized in that: The lubricant is one or a combination of multiple ones among ethylene bisstearamide, ethylene bis(12-hydroxystearamide), pentaerythritol tetrastearate, pentaerythritol tristearate, pentaerythritol distearate, pentaerythritol monostearate, glycerol tristearate, glycerol distearate, glycerol monostearate, erucamide, and oleamide.

8. The foaming-grade biodegradable polyester material according to claim 1 or 2, characterized in that: The cell nucleating agent is one or a combination of multiple ones among calcium carbonate powder, talcum powder, nano-silica powder, and montmorillonite powder.

9. A preparation method of a foaming-grade biodegradable polyester material, characterized in that it includes the following steps: (1) By weight, prepare the following raw materials: 91.90 - 99.78% of biodegradable polyester, 0.01 - 0.1% of organic peroxide, 0.10 - 3.00% of diallyl bisphenol A diglycidyl ether, 0.01 - 2.00% of lubricant, and 0.10 - 3.00% of cell nucleating agent; (2) Dry the biodegradable polyester at 45°C - 120°C for 60 min - 120 min to make the moisture content of the biodegradable polyester lower than 200 ppm, and cool it to 10°C - 30°C; (3) Add the organic peroxide and diallyl bisphenol A diglycidyl ether to the biodegradable polyester and mix evenly to obtain a mixed material; (4) Dry the cell nucleating agent at 100°C - 150°C for 60 min - 120 min to make its moisture content lower than 200 ppm, and cool it to 10°C - 30°C; (5) Add the lubricant and the cell nucleating agent obtained in step (4) to the mixed material obtained in step (3) and mix evenly to obtain a second mixed material; (6) Melt-extrude the second mixed material through a twin-screw extruder to obtain a foaming-grade biodegradable polyester material.

10. The preparation method of the foaming-grade biodegradable polyester material according to claim 9, characterized in that: The length-diameter ratio of the screw of the twin-screw extruder in step (6) is 40:1 - 52:1; The temperature of the twin-screw extruder in step (6) is 150°C - 220°C; In step (6), melt the second mixed material through a twin-screw extruder and extrude a strip, and cool and pelletize the strip to obtain a granular foaming-grade biodegradable polyester material.

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