Degradable plastic easy for laser marking as well as preparation method and application thereof

Abstract

The invention discloses degradable plastic easy for laser marking and a preparation method and application thereof, and belongs to the technical field of high polymer material modification, and the degradable plastic easy for laser marking comprises the following preparation raw materials: PLA, PBAT, an ultraviolet light absorber, a chain extender, an antioxidant and self-made white-to-black laser marking master batch. Wherein the white-to-black laser marking master batch promotes dispersion of a laser marking auxiliary agent and reduces the addition amount of the laser marking auxiliary agent, and meanwhile, the white-to-black laser marking master batch also plays a compatibilization effect on preparation of the degradable plastic easy for laser marking. The material has biodegradability meeting the standard and an excellent white-to-black laser marking effect. The material can be applied to degradable plastic packaging materials through injection molding.

Description

Technical Field

[0001] The invention relates to the technical field of polymer material modification, and in particular to a biodegradable plastic that is easy to be laser-marked, and a preparation method and application thereof. Background Art

[0002] Laser marking has the advantages of clear, high automation and not easy to lose the marking information. It has become more and more popular in the market in recent years. As a new marking method, laser marking technology has the advantages of environmental friendliness, permanent marking and flexible marking. At the same time, laser marking has the characteristics of fast speed, high precision and high automation, which makes it rapidly replace traditional ink printing and screen printing, and become an efficient and conventional processing method used in various industries.

[0003] Plastic products such as packaging materials made of high molecular compounds such as polystyrene, polypropylene, and polyvinyl chloride are discarded as solid waste after use. Due to random littering and difficulty in degradation, the pollution caused to the ecological environment and landscape is collectively referred to as white pollution. The global waste plastic recycling problem needs to be solved urgently, and relevant government departments continue to introduce plastic bans and related policies. The degradable plastic industry is ready to go. In order to alleviate the white pollution problem caused by conventional plastics, packaging materials prepared by degradable plastics are increasingly attracting market attention. At present, the fully biodegradable plastics that have been widely used in the market are polylactic acid (PLA) and polybutylene adipate-terephthalate (PBAT). PLA has excellent transparency and biocompatibility, but because of its shortcomings such as high crystallinity, brittleness, low impact strength and poor heat resistance, its industrial application is limited. PBAT has good ductility and elongation at break, as well as good heat resistance and impact resistance. Therefore, PLA and PABT are often extruded and blended into PLA / PBAT alloys to make up for the defects of the two materials. Since PLA and PBAT have poor compatibility, compatibilizers are often needed to increase the compatibility of PLA / PBAT alloys in order to improve the mechanical properties of the material.

[0004] Chinese patent CN116178851A discloses a styrene composite, product, preparation method and application thereof. The method uses a styrene polymer as a substrate, adds a specific amount of black-on-white laser marking agent, and can laser engrave a white mark inside the substrate, but the composite does not meet the requirements of biodegradable plastics. Chinese patent CN115011091A discloses a polylactic acid composition for laser marking and a preparation method thereof. The polylactic acid composition includes a polylactic acid resin and a laser marking agent. The polylactic acid composition can significantly improve the clarity of laser marking of polylactic acid materials, but the amount of laser marking additive required for the composition is relatively large. At the same time, polylactic acid as the matrix resin of the material has the characteristics of high crystallinity, brittleness and poor toughness (elongation at break 4-8%, flexural modulus 100-150MPa, notched impact strength 20-60Kj / m. The laser marking material is very easy to break during sample preparation and has poor processing performance. The finished product prepared by the material has great limitations during use.

[0005] In order to obtain a degradable plastic that is easy to mark with laser marking, has good laser marking effect, is biodegradable, and has mechanical properties that meet the requirements of packaging materials, while improving the processing performance of the product, the improvement of laser marking additives and compatibilizers is particularly important. The purpose of the present invention is to study how to effectively improve the laser marking effect by blending the components of various functional additives in the system without sacrificing the mechanical properties of the degradable plastic that is easy to mark and using as little laser marking additives as possible. Summary of the invention

[0006] In view of the above-mentioned defects in the prior art, a biodegradable plastic that is easy to be laser marked is prepared to meet the requirements for use as a biodegradable plastic packaging material.

[0007] The objective of the present invention is achieved through the following technical solutions:

[0008] A biodegradable plastic that is easy to mark with laser, comprising the following components in parts by weight:

[0009] PLA 50-80 parts;

[0010] PBAT 20-50 parts;

[0011] 0.1-2 parts of ultraviolet light absorber;

[0012] Chain extender 0.1-0.5 parts;

[0013] Antioxidant 0.2-1 part;

[0014] 3-10 copies of white on black laser marking masterbatch.

[0015] Preferably, the melt flow rate of the PLA is 1-10 g / 10 min, and the melt flow rate of the PBAT is 2-12 g / 10 min.

[0016] Preferably, the melt flow rate of the PLA is 1-5 g / 10 min, and the melt flow rate of the PBAT is 2-6 g / 10 min.

[0017] Preferably, the ultraviolet light absorber is a benzotriazole ultraviolet light absorber, and the benzotriazole ultraviolet light absorber is one or more of Lianlong UV-324, UV-326, UV-329, and UV-360. Plastic products will age and change color when exposed to sunlight; this is due to the effect of ultraviolet rays in sunlight. In order to extend the service life of plastic products, ultraviolet light absorbers are usually added during the preparation process of plastics.

[0018] Preferably, the chain extender is a reactive epoxy functional chain extender, and the reactive epoxy functional chain extender is one or more of BASF ADR4468, Coase BP-5, and Jiayirong HPC-3510P. Biodegradable PLA / PBAT alloy material, due to its poor ester stability, is easily degraded to generate more carboxyl and hydroxyl groups during twin-screw shearing. In order to efficiently end-cap the polyester end and prevent further degradation, a chain extender needs to be added. The addition of the chain extender can effectively improve the melt strength and mechanical properties of the material.

[0019] Preferably, the antioxidant is a compound of a hindered phenolic primary antioxidant and a phosphite secondary antioxidant, wherein the primary antioxidant is one or both of Lianlong antioxidant 1076 and Lianlong antioxidant 1010, and the secondary antioxidant is one or both of Lianlong antioxidant 168 and Lianlong antioxidant 626. The primary antioxidant can effectively slow down the breakage of the polymer chain of the raw material melt under high temperature and high shear during the co-extrusion of the degradable plastic in a twin-screw extruder, which eventually leads to the degradation of the material, and the secondary antioxidant can effectively reduce the yellowing of the material caused by the contact of the finished degradable plastic with oxygen in the air. This further affects the appearance and material properties of the degradable plastic. The present invention uses a compound of the primary antioxidant and the secondary antioxidant, which can more effectively prevent the degradation caused by high temperature and high shear during the material preparation process, and can also prevent the degradable plastic material from being oxidized and discolored by the environment during long-term use, thereby obtaining long-term stability.

[0020] Preferably, the white-on-black laser marking masterbatch is prepared by simultaneously adding 30-70 parts of PLA, 30-70 parts of PBAT, and 5-10 parts of MAH into a Haake torque rheometer for mixing, the mixing temperature is 160-180°C, the rotation speed is 100rpm, and after mixing for 2 minutes, 0.5-1.5 parts of DCP are added, and after continuing to mix for 5 minutes, 0.3-1 parts of silicone powder and 1-2 parts of white-on-black laser marking additives are added, and mixing is continued for 3 minutes, and finally granulated and dried at 80°C for 4 hours.

[0021] A method for preparing a biodegradable plastic that is easy to be laser marked comprises the following steps: drying PBAT and PLA in an oven at 80° C. for 4 hours in proportion, and then uniformly mixing the components of the raw materials in a high-speed mixer, and then passing through a twin-screw extruder, melt blending, shear extrusion, strand drawing, water cooling, air cooling, granulation, and drying to finally obtain a product.

[0022] Preferably, the processing temperature of each zone of the twin-screw extruder is 130° C.-190° C., and the speed of the twin-screw extruder is 100-500 rpm; the stirring time of the high-speed mixer is 3-7 min, and the speed is 200-500 rpm.

[0023] Preferably, the processing temperature of each zone of the twin-screw extruder is 150° C.-180° C., and the rotation speed of the twin-screw extruder is 200-300 rpm; the stirring time of the high-speed mixer is 4-5 min, and the rotation speed is 300-400 rpm.

[0024] The invention discloses an application of a biodegradable plastic that is easy to be laser-marked in a laser-marked packaging material.

[0025] The beneficial effects of this technical solution are as follows:

[0026] 1. The present invention provides a method for preparing a biodegradable plastic that is easy to be laser marked. The biodegradable plastic packaging material prepared by adding laser marking masterbatch to PLA / PBAT alloy and extruding the mixture through a twin-screw extruder has no significant difference in tensile strength, tensile modulus and cantilever beam notched impact strength, thereby maintaining the excellent mechanical properties of the PLA / PBAT alloy as a packaging material. At the same time, the biodegradable matrix portion of the packaging material is greater than 90%, which meets the biodegradability standards of biodegradable plastics and meets the use requirements of biodegradable green packaging materials.

[0027] 2. The present invention provides a biodegradable plastic that is easy to be laser-marked. The PLA / PBAT alloy is used as a base material, a specific amount of self-made white-on-black laser marking masterbatch is added, and a biodegradable plastic packaging material is prepared by blending and extruding through a twin-screw extruder. A black logo can be laser-marked on the packaging material. The white-on-black laser marking masterbatch systems prepared by the present invention are evenly dispersed in the PLA / PBAT alloy, and the laser marking additive accounts for about 0.03%-0.2% of the entire material, which brings an extremely excellent laser marking effect with a very small addition amount.

[0028] 3. The present invention provides a biodegradable plastic that is easy to be laser marked. The addition of a small amount of silicone powder during the preparation of laser marking masterbatch has two functions without affecting the mechanical properties of the base resin. One is to act as a lubricant to help disperse the laser marking additive in the laser marking masterbatch. The other is to act as a scratch-resistant agent to help improve the scratch resistance of the prepared biodegradable plastic packaging material that is easy to be laser marked.

[0029] 4. The present invention provides a biodegradable plastic that is easy to be laser marked. During the preparation of the laser marking masterbatch, the active group of MAH can react with the active hydroxyl groups in the PLA and PBAT macromolecular chains under the initiation of DCP to form a PLAB / PBAT macromolecular chain with a branched network structure. This network structure not only has an excellent volume-increasing effect on the PLA / PBAT alloy, but also helps to reduce the precipitation of the compatibilizer prepared by mixing in the laser marking masterbatch on the surface of the biodegradable plastic packaging material, and has good application value. DETAILED DESCRIPTION

[0030] The present invention is further described in detail below in conjunction with examples, but the embodiments of the present invention are not limited thereto.

[0031] The raw materials:

[0032] The raw material PLA comes from Zhejiang Hisun Biomaterials Co., Ltd., and the raw material PLA brand needs to be selected according to different melt flow rates.

[0033] The raw material PBAT comes from Xinjiang Lanshan Tunhe New Materials Co., Ltd., and the raw material PBAT brand needs to be selected according to different melt flow rates.

[0034] The ultraviolet light absorbers come from Tianjin Lianlong New Materials Co., Ltd., with brand names UV-360, UV-324, UV-326, and UV-329.

[0035] The chain extender comes from Coase Chemical Co., Ltd. and its brand is BP-5.

[0036] The chain extender is from BASF Chemical Co., Ltd. and its brand is ADR4468.

[0037] The chain extender comes from Jiayirong Polymer Co., Ltd. and its brand name is HPC-3510P.

[0038] The main antioxidant comes from Tianjin Lianlong New Materials Co., Ltd., with the brand names Antioxidant 1010 and Antioxidant 1076.

[0039] The auxiliary antioxidants come from Tianjin Lianlong New Materials Co., Ltd., with brand names Antioxidant 168 and Antioxidant 626.

[0040] DCP was obtained from Tianjin Bodi Chemical Co., Ltd. and was reagent grade.

[0041] MAH was sourced from Shandong Mantanghong New Materials Co., Ltd., industrial grade.

[0042] The silicone powder comes from China Bluestar Chenguang Chemical Research and Design Institute Co., Ltd., and its brand name is GM-100A.

[0043] The white-on-black laser marking additive comes from Merck Optoelectronic Materials Co., Ltd., and the brand name is Iriotec8825.

[0044] The processing equipment:

[0045] 1) The laser-markable biodegradable plastic packaging material is prepared by a TSS-40 co-rotating twin-screw extruder granulator. The parallel co-rotating twin-screw extruder is provided with an exhaust port and a vacuum port, which are helpful for the discharge of organic volatiles and the dissipation of odors.

[0046] 2) White on black laser marking masterbatch is prepared by mixing using a Haake torque rheometer.

[0047] Example 1

[0048] 1. Preparation of white-on-black laser marking masterbatch:

[0049] 50 parts of PLA, 45 parts of BPAT and 5 parts of MAH dried in a blast oven at 80°C for 4 hours were added to the Haake torque rheometer for mixing at a mixing temperature of 170°C and a rotation speed of 100rpm. After mixing for 2 minutes, 1.0 part of DCP was added, and after continuing to mix for 5 minutes, 0.5 parts of GM-100A and 1.5 parts of white-on-black laser marking aids were added. Mixing was continued for 3 minutes, extruded into granules and dried in a blast oven at 80°C for 4 hours to obtain the white-on-black laser marking masterbatch. Among them, MAH was mixed with PLA and PBAT in the Haake torque rheometer under the initiation of DCP, and the resulting grafted network polymer could effectively increase the volume of the PLA / PBAT alloy. After adding silicone powder (GM-100A), the laser marking aid could be effectively dispersed in the masterbatch, thereby improving the laser marking performance and scratch resistance of plastic products.

[0050] 2. Preparation of biodegradable plastic packaging materials that are easy to laser mark:

[0051] 65 parts of PLA, 30 parts of PBAT, 5 parts of white-on-black laser marking masterbatch, 0.5 parts of UV-360, 0.3 parts of BP-5, 0.3 parts of antioxidant 1010 and 0.1 parts of antioxidant 168 dried in a blast oven at 80°C for 4 hours were added to a high mixer and mixed evenly. The evenly mixed raw materials were passed through a twin-screw extruder for melting, extrusion, stranding, cooling, drying and granulation to obtain a packaging material that is easy to be laser marked. The processing temperature of the extruder was 160°C and the screw speed was 300rpm.

[0052] Wherein: the melt flow rate of PLA is 5g / 10min (190°C, 2.16Kg); the melt flow rate of PBAT is 4g / 10min (190°C, 2.16Kg); the stirring time of the high mixer is 5min, and the rotation speed is 300rpm.

[0053] Embodiment 2-5

[0054] Example 2-5 provides a biodegradable plastic packaging material that is easily laser marked, wherein the preparation methods of the white-on-black laser marking masterbatch and the biodegradable plastic packaging material that is easily laser marked are consistent with those of Example 1, and the addition amount of each component and the processing parameters are as shown in Table 1.

[0055] Table 1: Formulas of components (by weight) and process parameters of Examples 1-5

[0056]

[0057]

[0058] Comparative Example 1

[0059] Comparative Example 1 provides a biodegradable plastic packaging material that is easily laser marked, wherein the preparation methods of the white-on-black laser marking masterbatch and the biodegradable plastic packaging material that is easily laser marked are consistent with those of Example 1, with the only difference being that the laser-marked biodegradable plastic matrix resin does not contain PLA, and the addition amounts of each component and the processing parameters are carried out according to Table 2.

[0060] Comparative Example 2

[0061] Comparative Example 2 provides a biodegradable plastic packaging material that is easily laser marked, wherein the preparation methods of the white-on-black laser marking masterbatch and the biodegradable plastic packaging material that is easily laser marked are consistent with those of Example 1, with the only difference being that the laser-marked biodegradable plastic matrix resin does not contain PBAT, and the addition amounts of each component and the processing parameters are carried out according to Table 2.

[0062] Comparative Example 3

[0063] Comparative Example 3 provides a biodegradable plastic packaging material that is easily laser marked, wherein the preparation methods of the white-on-black laser marking masterbatch and the biodegradable plastic packaging material that is easily laser marked are consistent with those of Example 1, with the only difference being that the PLA melt flow rate in the laser marked biodegradable plastic is different, and the addition amount of each component and the processing parameters are carried out according to Table 2.

[0064] Comparative Example 4

[0065] Comparative Example 4 provides a biodegradable plastic packaging material that is easily laser marked, wherein the preparation methods of the white-on-black laser marking masterbatch and the biodegradable plastic packaging material that is easily laser marked are the same as those in Example 1, with the only difference being that the melt flow rate of PBAT in the laser marked biodegradable plastic is different, and the addition amount of each component and the processing parameters are carried out according to Table 2.

[0066] Comparative Example 5

[0067] Comparative Example 5 provides a biodegradable plastic packaging material that is easily laser marked, wherein the preparation method of the white-on-black laser marking masterbatch and the biodegradable plastic packaging material that is easily laser marked is consistent with that of Example 2, the only difference being that the laser marking masterbatch does not contain a laser marking aid, and the addition amount of each component and the processing parameters are carried out according to Table 2.

[0068] Comparative Example 6

[0069] Comparative Example 6 provides a biodegradable plastic packaging material that is easily laser marked, wherein the preparation method of the white-on-black laser marking masterbatch and the biodegradable plastic packaging material that is easily laser marked is consistent with that of Example 2, with the only difference being that the laser marked biodegradable plastic does not contain the laser marking masterbatch, and the laser marking aid is added separately to the laser marked biodegradable plastic, and the addition amount of each component and the processing parameters are carried out according to Table 2.

[0070] Comparative Example 7

[0071] Comparative Example 7 provides a biodegradable plastic packaging material that is easily laser marked, wherein the preparation method of the white-on-black laser marking masterbatch and the biodegradable plastic packaging material that is easily laser marked is consistent with that of Example 3, with the only difference being that the laser marked biodegradable plastic does not contain an antioxidant, and the addition amount of each component and the processing parameters are carried out according to Table 2.

[0072] Comparative Example 8

[0073] Comparative Example 8 provides a biodegradable plastic packaging material that is easily laser marked, wherein the preparation method of the white-on-black laser marking masterbatch and the biodegradable plastic packaging material that is easily laser marked is consistent with that of Example 3, with the only difference being that the laser marked biodegradable plastic does not contain a chain extender, and the addition amount of each component and the processing parameters are carried out according to Table 2.

[0074] Comparative Example 9

[0075] Comparative Example 9 provides a biodegradable plastic packaging material that is easily laser marked, wherein the preparation methods of the white-on-black laser marking masterbatch and the biodegradable plastic packaging material that is easily laser marked are consistent with those of Example 4, with the only difference being that the laser marking masterbatch does not contain PLA, and the addition amounts of each component and the processing parameters are carried out according to Table 2.

[0076] Comparative Example 10

[0077] Comparative Example 10 provides a biodegradable plastic packaging material that is easily laser marked, wherein the preparation method of the white-on-black laser marking masterbatch and the biodegradable plastic packaging material that is easily laser marked is consistent with that of Example 4, the only difference being that the laser marking masterbatch does not contain PBAT, and the addition amount of each component and the processing parameters are carried out according to Table 2.

[0078] Comparative Example 11

[0079] Comparative Example 11 provides a biodegradable plastic packaging material that is easily laser marked, wherein the preparation method of the white-on-black laser marking masterbatch and the biodegradable plastic packaging material that is easily laser marked is consistent with that of Example 4, the only difference being that the laser marking masterbatch does not contain silicone powder GM-100, and the addition amount of each component and the processing parameters are carried out according to Table 2.

[0080] Comparative Example 12

[0081] Comparative Example 12 provides a biodegradable plastic packaging material that is easily laser marked, wherein the preparation method of the white-on-black laser marking masterbatch and the biodegradable plastic packaging material that is easily laser marked is consistent with that of Example 5, the only difference being that the stirring time and stirring speed of the preparation high-speed mixer are different, and the addition amount of each component and the processing parameters are carried out according to Table 2.

[0082] Table 2 Comparative Examples 1-12 Components (parts by weight) and process parameters

[0083]

[0084]

[0085]

[0086] Examples 1-5 and Comparative Examples 1-12 all adopt the following performance testing method:

[0087] 1) Tensile strength

[0088] The tensile strength test of the sample is based on the national standard GB / T 1040, the test specimen thickness is 4mm, and the tensile rate is 50mm / min.

[0089] 2) Flexural modulus

[0090] The bending modulus of the specimen is tested according to the national standard GB / T 9341. The thickness of the test specimen is 4 mm and the bending rate is 2 mm / min.

[0091] 3) Notched impact strength

[0092] The notched impact strength test of the specimen is based on the national standard GB / T 1843, the test specimen thickness is 4mm, and the cantilever beam notched impact strength is tested.

[0093] 4) White on black laser marking test

[0094] Use the mold for testing transmittance and haze (national standard GB / T 2410) to inject 100×100×2mm square plates. Use a laser marking machine to mark a solid square of 10×10mm in the middle of the square plate, and use a colorimeter to test the color difference L value of the solid square. The lower the L value, the better the white-on-black effect.

[0095] Table 3 Physical property test data of Examples 1-5 and Comparative Examples 1-12

[0096]

[0097] It can be seen from Table 1 and Table 3 that there is no obvious difference in the performance of Examples 1-5 falling within the scope of the present invention.

[0098] As shown in Tables 2 and 3, the degradable plastic matrix resin in Comparative Example 1 does not contain PLA, and injection molding cannot be performed using only PBAT as the matrix resin. The degradable plastic matrix resin in Comparative Example 2 does not contain PBAT, and it is easy to break during the granulation process compared with Example 1, and the bending modulus and notched impact strength of the product are too low. Comparative Examples 3 and 4 respectively use PLA and PBAT with melt flow rates higher than the range of the present invention, and their performance is also lower than that of Example 1. Comparative Example 5 is a product without adding laser marking additives, and its mechanical properties are not significantly different from those of Example 2, but since this material does not contain laser marking additives, its color difference L value is relatively high, indicating that white-on-black laser marking cannot be effectively performed.

[0099] Comparative Example 6 Since the material does not contain homemade laser marking masterbatch, the prepared PBAT / PLA alloy cannot be expanded, so the phenomenon of broken strips and phase separation occurs during the extrusion process. At the same time, the product cannot be injection molded due to the lack of good compatibility. Comparative Example 7 effectively illustrates that the addition of an antioxidant system helps to alleviate the yellowing and lack of mechanical properties caused by material degradation. Comparative Example 8 effectively illustrates that the addition of a chain extender can help improve the mechanical properties of the degradable plastic PBAT / PLA alloy material.

[0100] Compared with Example 4, since the homemade laser marking masterbatch does not contain PLA, PBAT and silicone powder GM-100A, the former two have the phenomenon of broken strips and phase separation during the granulation process, and the latter lacks the lubrication and dispersion of the silicone powder on the laser marking additive, resulting in a higher color difference L value of the product and a poor white-on-black laser marking effect.

[0101] Comparative Example 12 is compared with Example 5, indicating that insufficient mixing of the raw materials in the high-speed mixer will also affect the performance stability of the laser-marked plastic.

[0102] It can be seen that the self-made laser marking masterbatch and the easy-to-laser-mark degradable plastic of the present invention can effectively improve the compatibility, mechanical properties and white-on-black laser marking effect of the easy-to-laser-mark plastic, thereby meeting the use requirements of degradable plastic packaging materials. Finally, it should be noted that the above embodiments are only used to illustrate, but not to limit the technical solutions of the present invention. Although the present invention is described in detail with reference to the above embodiments, ordinary technicians in this field should understand that the present invention can still be modified or equivalently replaced, and any modification or partial replacement that does not depart from the spirit and scope of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A biodegradable plastic that is easy to laser mark, characterized in that: The composition comprises the following components in parts by weight: PLA 50-80 parts; PBAT 20-50 parts; 0.1-2 parts of ultraviolet light absorber; Chain extender 0.1-0.5 parts; Antioxidant 0.2-1 part; 3-10 copies of white on black laser marking masterbatch.

2. The biodegradable plastic that is easy to mark with laser according to claim 1, characterized in that: The melt flow rate of the PLA is 1-10 g / 10 min, and the melt flow rate of the PBAT is 2-12 g / 10 min.

3. The biodegradable plastic that is easy to mark with laser according to claim 1, characterized in that: The melt flow rate of the PLA is 1-5 g / 10 min, and the melt flow rate of the PBAT is 2-6 g / 10 min.

4. The biodegradable plastic that is easy to mark with laser according to claim 1, characterized in that: The ultraviolet light absorber is a benzotriazole ultraviolet light absorber, and the benzotriazole ultraviolet light absorber is one or more of Lianlong UV-324, UV-326, UV-329, and UV-360.

5. The biodegradable plastic that is easy to mark with laser according to claim 1, characterized in that: The chain extender is a reactive epoxy functional chain extender, and the reactive epoxy functional chain extender is one or more of BASF ADR4468, Coase BP-5, and Jiayirong HPC-3510P.

6. The biodegradable plastic that is easy to mark with laser according to claim 1, characterized in that: The antioxidant is a compound of a hindered phenol main antioxidant and a phosphite auxiliary antioxidant. The main antioxidant is one or both of Lianlong Antioxidant 1076 and Lianlong Antioxidant 1010, and the auxiliary antioxidant is one or both of Lianlong Antioxidant 168 and Lianlong Antioxidant 626.

7. The biodegradable plastic that is easy to mark with laser according to claim 1, characterized in that: The white-on-black laser marking masterbatch is prepared by adding 30-70 parts of PLA, 30-70 parts of PBAT, and 5-10 parts of MAH into a Haake torque rheometer for mixing at a mixing temperature of 160-180° C. and a rotation speed of 100 rpm. After mixing for 2 minutes, 0.5-1.5 parts of DCP are added. After mixing for 5 minutes, 0.3-1 parts of silicone powder and 1-2 parts of a white-on-black laser marking additive are added. Mixing is continued for 3 minutes, and finally granulation is performed and dried at 80° C. for 4 hours.

8. A method for preparing a biodegradable plastic that is easily laser marked, characterized in that: PBAT and PLA are dried in an oven at 80°C for 4 hours in proportion, and then the raw material components are mixed evenly in a high-speed mixer, and then passed through a twin-screw extruder, melt blending, shear extrusion, strand drawing, water cooling, air cooling, granulation, and drying to finally obtain the product.

9. The method for preparing a biodegradable plastic that is easily laser-marked according to claim 8, characterized in that: The processing temperature of each zone of the twin-screw extruder is 130° C.-190° C., and the rotation speed of the twin-screw extruder is 100-500 rpm; the stirring time of the high-speed mixer is 3-7 minutes, and the rotation speed is 200-500 rpm.

10. The method for preparing a biodegradable plastic that is easily laser-marked according to claim 8, characterized in that: The processing temperature of each zone of the twin-screw extruder is 150° C.-180° C., and the rotation speed of the twin-screw extruder is 200-300 rpm; the stirring time of the high-speed mixer is 4-5 minutes, and the rotation speed is 300-400 rpm.

11. Use of the easily laser-markable biodegradable plastic according to any one of claims 1 to 7 in laser-marked packaging materials.

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