Biodegradable plastic sheet and preparation method thereof

Abstract

The invention provides a biodegradable plastic sheet and a preparation method thereof, and belongs to the technical field of biodegradable plastics. Comprising the following components in parts by weight: 10 to 40 parts of poly (butylene terephthalate)-adipate, 10 to 35 parts of poly (butylene terephthalate)-adipate, 5 to 30 parts of polylactic acid, 10 to 30 parts of a filling agent, 0.1 to 1 part of a nucleating agent, 1 to 10 parts of a plasticizer, 0.5 to 2 parts of a lubricant, 0.1 to 1 part of an antioxidant, 0.1 to 1 part of a light stabilizer and 0.1 to 0.5 part of a chain extender, the preparation method of the filler comprises the step of mixing the filler and the coupling agent in a heating state for activation. According to the technical scheme provided by the invention, the purposes of simple preparation method and excellent mechanical property of the obtained material are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of biodegradable plastics, and in particular to a biodegradable plastic sheet and a preparation method thereof. Background Art

[0002] Biodegradable plastics refer to plastic materials that can be completely decomposed into low molecular weight compounds by natural microorganisms such as bacteria, fungi and algae. Compared with traditional non-degradable plastics, biodegradable plastics have advantages in many aspects, such as no harm to the natural environment, no harmful gas release, compostable, and lower processing costs.

[0003] For example, the publication number CN113402780A, entitled A sheet-grade fully biodegradable polyester and its preparation method, discloses that corn starch, CaCO3, PBAT, and PLA are used as raw materials, lubricants, chain extenders and other additives are added, and sheets are extruded through a twin-screw extruder. Compared with ordinary plastics, the mechanical and physical properties are the same, and it can be completely degraded in the natural environment, which helps to reduce dependence on petroleum-based materials. However, the above technical solution cannot improve the mechanical properties of the material.

[0004] For example, the publication number CN113321902B, entitled A degradable blister tray and production process, discloses PBSA resin, graphene composite modified starch, plasticizer, antioxidant 1010, lubricant, coupling agent, inorganic filler, etc. By introducing graphene composite modified starch, the processing performance and degradability of the degradable blister tray can be improved, and the dispersibility of graphene composite modified starch is improved, and the mechanical properties of the blister tray are improved. However, the modification steps in the above technical solution are cumbersome and difficult to expand production. Summary of the invention

[0005] In view of this, the present invention provides a biodegradable plastic sheet and a preparation method thereof, which achieves the purpose of simple preparation method and excellent mechanical properties of the obtained material.

[0006] To achieve the above-mentioned purpose, the present invention provides a biodegradable plastic sheet, comprising the following components in parts by weight: 10-40 parts of poly(butylene terephthalate-adipate), 10-35 parts of poly(butylene terephthalate-adipate), 5-30 parts of polylactic acid, 10-30 parts of filler, 0.1-1 parts of nucleating agent, 1-10 parts of plasticizer, 0.5-2 parts of lubricant, 0.1-1 parts of antioxidant, 0.1-1 parts of light stabilizer and 0.1-0.5 parts of chain extender; the preparation method of the filler comprises mixing the filler and the coupling agent under heating for activation.

[0007] Optionally, the filler includes one or a combination of two or more of calcium carbonate, talc, white carbon black, carbon black and wollastonite, and the filler particle size is greater than or equal to 400 meshes.

[0008] Optionally, the coupling agent includes one of a silane coupling agent, an aluminate coupling agent and a titanate coupling agent.

[0009] Optionally, the coupling agent is diluted during the mixing to a coupling agent concentration of 5-20% in the solution, and the solution is adjusted to a pH of 4-5.

[0010] Optionally, the plasticizer is one or a combination of two or more of acetyl tributyl citrate, polyethylene glycol 400, glycerin, dioctyl phthalate, tetraoctyl pyromellitate and epoxy soybean oil.

[0011] Optionally, the lubricant is one or a combination of two or more of ethylene bisstearamide, zinc stearate, calcium stearate, polyethylene wax, erucic acid amide and white oil.

[0012] Optionally, the light stabilizer is one or a combination of two or more of 2-(2-hydroxy-5-methylphenyl)benzotriazole, 2-hydroxy-4-methoxybenzophenone and 2-hydroxy-4-octyloxybenzophenone.

[0013] Optionally, the antioxidant includes one or a combination of two or more of the antioxidant 264, the antioxidant 1010 and the antioxidant 168.

[0014] Optionally, the chain extender includes BASF chain extenders ADR4400 and ADR4468.

[0015] Optionally, the nucleating agent is an inorganic nucleating agent or an organic nucleating agent, and the inorganic nucleating agent includes nano calcium carbonate and ultrafine talc.

[0016] Optionally, the polybutylene terephthalate-adipate-glycol has a melt index of 3-4.5 g / 10 min at a temperature of 190° C. and a load of 2.16 kg.

[0017] Optionally, the melt index of the polybutylene succinate-adipate ester is less than or equal to 10 g / 10 min at a temperature of 190° C. and a load of 2.16 kg.

[0018] Optionally, the optical purity of the polylactic acid is 80-100%, and the weight average molecular weight is 2000-30000Da.

[0019] In order to achieve the above object, the present invention also provides a method for preparing a biodegradable plastic sheet, comprising the following steps: S1. The dried poly(butylene terephthalate)-adipate, poly(butylene succinate)-adipate, polylactic acid and filler are added to a high-speed mixer and mixed, and a plasticizer, a chain extender, a lubricant, a nucleating agent, an antioxidant and a light stabilizer are added successively, and the mixture is mixed uniformly to obtain a mixture; S2. The mixture is melted, mixed, sheared, extruded after sufficient reaction, and then tableted, cooled, and shaped to obtain a biodegradable plastic sheet.

[0020] Optionally, a twin-screw extruder is used in S2, wherein the aspect ratio of the twin-screw extruder is 52:1, the temperature is 120-160°C, the screw speed is 130 rpm, and the feeding frequency is 2.5 Hz.

[0021] The above technical solution of the present invention includes at least the following beneficial effects: The biodegradable plastic sheet provided by the present invention processes the filler in different ways, and combines raw materials and additives such as poly(butylene terephthalate-adipate) (PBAT), poly(butylene succinate-adipate) (PBSA), polylactic acid (PLA), etc., so as to achieve a tensile strength of 20.5-30.3Mpa and an elongation at break of 107.2-337.1%. The sheet has excellent mechanical properties and excellent biodegradability, and can be used to produce products such as blister trays and seedling trays. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a process flow chart of the biodegradable plastic sheet in an embodiment of the present invention. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described in combination with the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0024] The poly(butylene terephthalate-adipate) used in the embodiment of the present invention has a melt index of 3-4.5 g / 10 min at a temperature of 190° C. and a load of 2.16 kg; the melt index of poly(butylene succinate-adipate) is less than or equal to 10 g / 10 min at a temperature of 190° C. and a load of 2.16 kg; the optical purity of polylactic acid is 80-100%, the weight-average molecular weight is 2000-30000 Da, and the particle size of the filler is greater than or equal to 400 mesh.

[0025] Example 1 By weight: 35 parts of polybutylene terephthalate (PBAT), 34 parts of polybutylene succinate (PBSA), 5 parts of polylactic acid (PLA), 20 parts of filler, 2 parts of acetyl tributyl citrate (ATBC), 2 parts of erucamide, 0.5 parts of chain extender ADR4468, 0.5 parts of nano calcium carbonate, 0.5 parts of antioxidant 1010, and 0.5 parts of 2-(2-hydroxy-5-methylphenyl) benzotriazole (UV-P).

[0026] 1. Preparation of filler: Filler formula: 100 parts of calcium carbonate, 1.5 parts of aluminate coupling agent, and 0.5 parts of stearic acid.

[0027] (1) 100 parts of calcium carbonate were heated to 110°C in a high-speed heating mixer to remove moisture; (2) Crush 1.5 parts of aluminate coupling agent, add half of it to calcium carbonate, mix for 3 minutes, add the rest to calcium carbonate, and continue mixing for 5 minutes; (3) Add 0.5 parts of stearic acid to calcium carbonate, continue mixing for 2 minutes, cool down, and take out for later use. This is the filler.

[0028] 2. Preparation of biodegradable plastic sheets (1) Add the dried PBAT, PBSA, PLA and the filler prepared in step 1 into a high-speed mixer and mix them. Add plasticizer, chain extender, lubricant, nucleating agent, antioxidant and light stabilizer one by one at intervals of 2 to 3 minutes. The total mixing time is controlled within 20 to 30 minutes. After mixing evenly, take out and set aside. (2) The above mixture is put into a twin-screw extruder, and after melting, mixing, shearing, and fully reacting, it is quantitatively extruded through the die head, and after tableting, cooling, and shaping, a biodegradable plastic sheet is obtained. The twin-screw extruder has a length-to-diameter ratio of 52:1, an extruder temperature of 120-160°C, a screw speed of 130rpm, and a feeding frequency of 2.5HZ.

[0029] Example 2 By weight: 40 parts of PBAT, 35 parts of PBSA, 30 parts of PLA, 20 parts of filler, 10 parts of polyethylene glycol 400 (PEG400), 1 part of ethylene bisstearamide EBS, 0.5 parts of chain extender ADR4400, 1 part of ultrafine talc, 0.8 parts of antioxidant 168, and 0.7 parts of 2-hydroxy-4-methoxybenzophenone (UV-9).

[0030] 1. Preparation of filler: Filler formula: 100 parts of talc powder and 1.5 parts of silane coupling agent KH-550.

[0031] (1) Dilute 1.5 parts of KH550 silane coupling agent into a 5% solution, the solvent is 72% ethanol + 8% water, and the pH of the solution is 4; (2) Spray the prepared silane coupling agent solution evenly on 100 parts of talcum powder, and mix at high speed for 10 to 20 minutes in a heating high-speed mixer at a speed of 300 to 500 r / min; (3) Raise the temperature to 120°C, remove excess water, and take out for later use. This is the filler. 2. Preparation of biodegradable plastic sheets (1) Add the dried PBAT, PBSA, PLA and the filler prepared in step 1 into a high-speed mixer and mix them. Add plasticizer, chain extender, lubricant, nucleating agent, antioxidant and light stabilizer one by one at intervals of 2 to 3 minutes. The total mixing time is controlled within 20 to 30 minutes. After mixing evenly, take out and set aside. (2) The above mixture is put into a twin-screw extruder, and after melting, mixing, shearing, and fully reacting, it is quantitatively extruded through the die head, and after tableting, cooling, and shaping, a biodegradable plastic sheet is obtained. The twin-screw extruder has a length-to-diameter ratio of 52:1, an extruder temperature of 120-160°C, a screw speed of 130rpm, and a feeding frequency of 2.5HZ.

[0032] Example 3 By weight: PBAT 37 parts, PBSA 25 parts, PLA 5 parts, filler 25 parts, dioctyl phthalate (DOP) 2 parts, zinc stearate 1.5 parts, calcium stearate 0.5 parts, chain extender ADR 4400 0.2 parts, ultrafine talc 0.4 parts, antioxidant 264 1 part, 2-hydroxy-4-octyloxybenzophenone (UV-531) 1 part.

[0033] 1. Preparation of filler: Filler formula: 100 parts of wollastonite and 1.5 parts of titanate coupling agent 201.

[0034] (1) Mix 1.5 parts of titanate coupling agent 201 and isopropyl alcohol in a ratio of 10:1; (2) Spray the prepared solution evenly on 100 parts of wollastonite and mix at high speed for 10-20 minutes in a heating high-speed mixer at a speed of 300-500 r / min; (3) Raise the temperature to 120°C, remove excess water, and take out for later use. This is the filler.

[0035] 2. Preparation of biodegradable plastic sheets (1) Add the dried PBAT, PBSA, PLA and the filler prepared in step 1 into a high-speed mixer and mix them. Add plasticizer, chain extender, lubricant, nucleating agent, antioxidant and light stabilizer one by one at intervals of 2 to 3 minutes. The total mixing time is controlled within 20 to 30 minutes. After mixing evenly, take out and set aside. (2) The above mixture is put into a twin-screw extruder, and after melting, mixing, shearing, and fully reacting, it is quantitatively extruded through the die head, and after tableting, cooling, and shaping, a biodegradable plastic sheet is obtained. The twin-screw extruder has a length-to-diameter ratio of 52:1, an extruder temperature of 120-160°C, a screw speed of 130rpm, and a feeding frequency of 2.5HZ.

[0036] Example 4 By weight: PBAT 15 parts, PBSA 20 parts, PLA 7 parts, filler 30 parts, DOP 5 parts, zinc stearate 1.5 parts, polyethylene wax 0.5 parts, ADR 4400 0.2 parts, ultrafine talc 0.1 parts, antioxidant 264 0.5 parts, UV-531 0.1 parts.

[0037] 1. Preparation of filler: Filler formula: 100 parts of white carbon black, 1.5 parts of KH550.

[0038] (1) Dilute 1.5 parts of KH550 silane coupling agent into a 20% solution, the solvent is 72% ethanol + 8% water, and the pH of the solution is 5; (2) Spray the prepared silane coupling agent solution evenly on 100 parts of white carbon black, and mix at high speed for 10 to 20 minutes in a heating high-speed mixer at a speed of 300 to 500 r / min; (3) Raise the temperature to 120°C, remove excess water, and take out for later use. This is the filler.

[0039] 2. Preparation of biodegradable plastic sheets (1) Add the dried PBAT, PBSA, PLA and the filler prepared in step 1 into a high-speed mixer and mix them. Add plasticizer, chain extender, lubricant, nucleating agent, antioxidant and light stabilizer one by one at intervals of 2 to 3 minutes. The total mixing time is controlled within 20 to 30 minutes. After mixing evenly, take out and set aside. (2) The above mixture is put into a twin-screw extruder, and after melting, mixing, shearing, and fully reacting, it is quantitatively extruded through the die head, and after tableting, cooling, and shaping, a biodegradable plastic sheet is obtained. The twin-screw extruder has a length-to-diameter ratio of 52:1, an extruder temperature of 120-160°C, a screw speed of 130rpm, and a feeding frequency of 2.5HZ.

[0040] Comparative Example 1 Compared with Example 3, the only difference is that white carbon black is directly used as the filler, and the other steps and raw materials are the same as those in Example 3.

[0041] Comparative Example 2 Compared with Example 4, the only difference is that wollastonite is directly used as the filler, and the remaining steps and raw materials are the same as those in Example 4.

[0042] The biodegradable plastic sheets prepared in Examples 1 to 4 and the biodegradable plastic sheets prepared in Comparative Examples 1 to 2 were subjected to relevant tests on mechanical properties. The test results are shown in Table 1.

[0043] Table 1 Mechanical properties data

[0044] In summary, the biodegradable plastic sheets obtained in Examples 1 to 4 are significantly stronger than the biodegradable plastic sheets prepared in Comparative Examples 1 to 2 in terms of tensile strength and elongation at break. It can be seen that the filler of the present invention can enhance the mechanical properties of the biodegradable plastic sheet. At the same time, the preparation method of the biodegradable plastic sheet provided by the present invention is simple and convenient for expanding production.

[0045] The above are preferred embodiments of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A biodegradable plastic sheet, characterized in that: The invention comprises the following components in parts by weight: 10-40 parts of poly(butylene terephthalate-adipate), 10-35 parts of poly(butylene terephthalate-adipate), 5-30 parts of polylactic acid, 10-30 parts of filler, 0.1-1 parts of nucleating agent, 1-10 parts of plasticizer, 0.5-2 parts of lubricant, 0.1-1 parts of antioxidant, 0.1-1 parts of light stabilizer and 0.1-0.5 parts of chain extender; the preparation method of the filler comprises the steps of mixing the filler and the coupling agent under heating for activation.

2. The biodegradable plastic sheet according to claim 1, characterized in that: The filler includes one or a combination of two or more of calcium carbonate, talc, white carbon black, carbon black and wollastonite, and the particle size of the filler is greater than or equal to 400 meshes.

3. The biodegradable plastic sheet according to claim 1, characterized in that: The coupling agent includes one of a silane coupling agent, an aluminate coupling agent and a titanate coupling agent.

4. The biodegradable plastic sheet according to claim 1, characterized in that: During the mixing, the coupling agent is diluted to a concentration of 5-20% in the solution, and the solution is adjusted to a pH of 4-5.

5. The biodegradable plastic sheet according to claim 1, characterized in that: The plasticizer is one or a combination of two or more of acetyl tributyl citrate, polyethylene glycol 400, glycerol, dioctyl phthalate, tetraoctyl pyromellitate and epoxy soybean oil.

6. The biodegradable plastic sheet according to claim 1, characterized in that: The lubricant is one or a combination of two or more of ethylene bis stearamide, zinc stearate, calcium stearate, polyethylene wax and white oil.

7. The biodegradable plastic sheet according to claim 1, characterized in that: The light stabilizer is one or a combination of two or more of 2-(2-hydroxy-5-methylphenyl)benzotriazole, 2-hydroxy-4-methoxybenzophenone and 2-hydroxy-4-octyloxybenzophenone.

8. The biodegradable plastic sheet according to claim 1, characterized in that: The antioxidant includes one or a combination of two or more of the antioxidant 264 , the antioxidant 1010 and the antioxidant 168 .

9. A method for preparing the biodegradable plastic sheet according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1. The dried poly(butylene terephthalate)-adipate, poly(butylene succinate)-adipate, polylactic acid and filler are added to a high-speed mixer and mixed, and a plasticizer, a chain extender, a lubricant, a nucleating agent, an antioxidant and a light stabilizer are added successively, and the mixture is mixed uniformly to obtain a mixture; S2. The mixture is melted, mixed, sheared, extruded after sufficient reaction, and then tableted, cooled, and shaped to obtain a biodegradable plastic sheet.

10. The method for preparing the biodegradable plastic sheet according to claim 9, characterized in that: A twin-screw extruder is used in S2, wherein the aspect ratio of the twin-screw extruder is 52:1, the temperature is 120-160°C, the screw speed is 130 rpm, and the feeding frequency is 2.5 Hz.

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