Tear-resistant high-barrier biodegradable mulching film and preparation method thereof

Abstract

The invention relates to the technical field of biodegradable high polymer materials, in particular to a tear-resistant high-barrier biodegradable mulching film and a preparation method thereof, and the tear-resistant high-barrier biodegradable mulching film is prepared from the following raw materials in parts by weight: 60-90 parts of poly (butylene adipate-co-terephthalate); 10 to 40 parts of poly (propylene carbonate); 0.5-5 parts of a plasticizer; 0.05 to 0.3 part of a cross-linking agent; 0.1 to 10 parts of talcum powder; 0.1 to 2 parts of a lubricant; 0.1-1 part of an anti-blocking agent; 0.1 to 1 part of an antioxidant; 0.1 to 1 part of an anti-ultraviolet agent; 0.1-1 part of a light stabilizer; 0.1 to 1 part of an anti-hydrolysis agent; 0.1-1 part of a nucleating agent; the plasticizer is poly (1, 2-propylene glycol adipate); and the cross-linking agent is 1, 4-bis (tert-butylperoxy) diisopropyl benzene. The film has good mechanical properties and water vapor transmission amount, can be completely biodegraded, and has good aging resistance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of biodegradable polymer materials, and particularly relates to an anti-tearing high-barrier biodegradable mulching film and a preparation method thereof. BACKGROUND

[0002] PBAT is a biodegradable polymer copolymerized by adipic acid, terephthalic acid and butanediol, and has very important significance for environmental protection. The performance of PBAT is similar to that of general plastic polyethylene, has certain toughness, is easy to blow into a film, and has good processability. However, the barrier property of PBAT is poor, far lower than that of polyethylene, which seriously limits its wide application in the field of mulching film.

[0003] In view of the poor barrier property of PBAT, domestic and foreign are actively carrying out modification research, and the main technical means at present is to improve the barrier property of PBAT by using the method of multi-component blending modification and then blow film processing. PPC is obtained by copolymerization of carbon dioxide and propylene oxide, has the effect of recycling carbon dioxide and reducing greenhouse effect, and is particularly important to develop and research PPC resin in the situation that greenhouse effect is becoming more and more serious and the global temperature is continuously rising. PPC has good ductility and the barrier property is obviously better than that of PBAT. Research shows that the addition of PPC can increase the tensile strength and gas barrier property of PBAT / PPC film.

[0004] At present, there are also PBAT, PLA and PPC ternary blend mulching film, polylactic acid, polypropylene carbonate, polybutylene adipate / terephthalate blend mulching film and the like.

[0005] However, the compatibility of PPC and PBAT is poor, the addition of PPC can improve the barrier property of PBAT, but at the same time, the mechanical properties of the material are affected, the tensile elongation at break and tear strength and other mechanical properties of the material are affected, and the prepared mulching film is easy to tear.

[0006] How to obtain PBAT modified resin with high barrier property and good mechanical property is a problem to be solved in the preparation of degradable mulching film at present. SUMMARY

[0007] Therefore, the present application aims to solve the technical problem and provide an anti-tearing high-barrier biodegradable mulching film and a preparation method thereof, which have high barrier property and mechanical property.

[0008] To achieve the above-mentioned purpose, the present application provides an anti-tearing high-barrier biodegradable mulching film, which is prepared from raw materials including the following weight parts:

[0009] polybutylene adipate-terephthalate 60-90 parts;

[0010] polypropylene carbonate 10-40 parts;

[0011] plasticizer 0.5~5 parts;

[0012] crosslinking agent 0.05~0.3 parts;

[0013] talc 0.1~10 parts;

[0014] lubricant 0.1~2 parts;

[0015] opening agent 0.1~1 part;

[0016] antioxidant 0.1~1 part;

[0017] anti-ultraviolet agent 0.1~1 part;

[0018] light stabilizer 0.1~1 part;

[0019] anti-hydrolysis agent 0.1~1 part;

[0020] nucleating agent 0.1~1 part;

[0021] the plasticizer is poly-1,2-propylene glycol adipate;

[0022] the crosslinking agent is 1,4-bis-tert-butyl peroxydiisopropyl benzene.

[0023] optionally, the content of the polybutylene adipate terephthalate is 60~75 parts;

[0024] the content of the polypropylene carbonate is 10~35 parts;

[0025] the content of the plasticizer is 1~3 parts;

[0026] the content of the crosslinking agent is 0.1~0.3 parts.

[0027] optionally, the lubricant is pentaerythritol stearate;

[0028] the content of the lubricant is 0.5~1.5 parts.

[0029] optionally, the opening agent is erucic acid amide or oleic acid amide;

[0030] the content of the opening agent is 0.5~1 part.

[0031] optionally, the antioxidant is triethylene glycol bis[β-(3-tert-butyl-4-hydroxy-5-methyl phenyl) propionate];

[0032] the content of the antioxidant is 0.1~0.5 parts.

[0033] Optionally, the anti-UV agent is bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate.

[0034] The content of the anti-UV agent is 0.2-0.5 parts.

[0035] Optionally, the light stabilizer is poly(4-hydroxy-2,2,6,6-tetramethyl-1-piperidinethanol) succinate.

[0036] The content of the light stabilizer is 0.3-0.8 parts.

[0037] Optionally, the anti-hydrolysis agent is polycarbodiimide.

[0038] The content of the anti-hydrolysis agent is 0.2-0.8 parts.

[0039] Optionally, the nucleating agent is 1,3,5-benzene triformamide derivative (N,N'-bis(benzoyl) sebacic dihydrazide).

[0040] The content of the nucleating agent is 0.1-0.5 parts.

[0041] The application provides a preparation method of the above-mentioned tear-resistant high-barrier biodegradable mulch film, comprising the following steps:

[0042] The polybutylene adipate terephthalate, polypropylene carbonate, plasticizer, crosslinking agent, talcum powder, lubricant, opening agent, antioxidant, anti-UV agent, light stabilizer, anti-hydrolysis agent and nucleating agent are mixed to obtain a premix.

[0043] The above-mentioned premix is extruded, granulated and blow molded into a film to obtain the tear-resistant high-barrier biodegradable mulch film.

[0044] Compared with the prior art, the application provides a tear-resistant high-barrier biodegradable mulch film prepared from raw materials comprising the following weight parts: polybutylene adipate terephthalate 60-90 parts; polypropylene carbonate 10-40 parts; plasticizer 0.5-5 parts; crosslinking agent 0.05-0.3 parts; talcum powder 0.1-10 parts; lubricant 0.1-2 parts; opening agent 0.1-1 part; antioxidant 0.1-1 part; anti-UV agent 0.1-1 part; light stabilizer 0.1-1 part; anti-hydrolysis agent 0.1-1 part; nucleating agent 0.1-1 part; the plasticizer is poly(1,2-propanediol adipate); and the crosslinking agent is 1,4-bis-tert-butyl peroxydiisopropylbenzene.

[0045] The application adds PPA as a plasticizer and BIBP as a crosslinking agent in the PBAT / PPC film, and the prepared blown film has good mechanical properties and water vapor transmission rate, the components are biodegradable, has the advantages of complete biodegradation, good aging resistance, wide application field, can replace PE, PP, PVC and the like, and can be made into various transparent environment-friendly shopping bags, preservative bags, express packaging bags and garbage bags, especially in the field of mulching film, can resist ultraviolet aging, has a broad market prospect, can be completely degraded into water and carbon dioxide in the soil, and industrialization is beneficial to the long-term development needs of energy and material resources, avoids pollution of non-degradable mulching film to soil, protects the soil environment, promotes the benign development of agricultural ecological environment protection, solves white pollution, effectively utilizes carbon dioxide, has great economic, social and environmental benefits, and has wide application value. DETAILED DESCRIPTION

[0046] The application provides an anti-tear high-barrier biodegradable mulching film, which is prepared from raw materials including the following components by weight:

[0047] Polybutylene adipate terephthalate 60-90 parts;

[0048] Polypropylene carbonate 10-40 parts;

[0049] Plasticizer 0.5-5 parts;

[0050] Crosslinking agent 0.05-0.3 parts;

[0051] Talcum powder 0.1-10 parts;

[0052] Lubricant 0.1-2 parts;

[0053] Opening agent 0.1-1 part;

[0054] Antioxidant 0.1-1 part;

[0055] Anti-ultraviolet agent 0.1-1 part;

[0056] Light stabilizer 0.1-1 part;

[0057] Anti-hydrolysis agent 0.1-1 part;

[0058] Nucleating agent 0.1-1 part;

[0059] The plasticizer is polyhexanedioic acid-1,2-propylene glycol ester;

[0060] The crosslinking agent is 1,4-bis-tert-butyl peroxydiisopropylbenzene.

[0061] The content of polybutylene adipate terephthalate (PBAT) is 60-90 parts, preferably 60-75 parts. In some specific embodiments, the content of polybutylene adipate terephthalate is 60, 65, 66, 67, 68, 69, 70, or 75 parts, or any of the above values ​​may be the upper or lower limit.

[0062] The content of the polypropylene carbonate (PPC) is 10 to 40 parts, preferably 10 to 35 parts. In some specific embodiments, the content of the polypropylene carbonate is 10, 15, 20, 25, or 30 parts, or any of the above values ​​are the upper or lower limits.

[0063] This invention uses PBAT and PPC as the main components. PBAT can improve the tensile elongation at break and tear strength of the film; PPC can improve the tensile elongation at break and UV aging resistance of the film, thereby improving the barrier properties of the film.

[0064] To avoid the influence of PPC on the mechanical properties of the material, this invention adds poly(1,2-propanediol adipate) (PPA) as a plasticizer to the PBAT / PPC system and uses 1,4-di-tert-butylperoxide diisopropylbenzene (BIBP) as a crosslinking agent.

[0065] The content of the plasticizer is 0.5 to 5 parts, preferably 1 to 3 parts. In some specific embodiments, the content of the plasticizer is 1, 2 or 3 parts, or any of the above values ​​are the upper or lower limits.

[0066] Using PPA as a migration-resistant plasticizer can improve the compatibility of PBAT and PPC, and increase the tensile elongation at break of the film. Furthermore, PPA is an aliphatic polyester with good molecular chain flexibility; adding it to the raw materials as a blending material can improve the flexibility of the blend. Moreover, PPA is a fully biodegradable compound, so the material blended with PBAT and PPC remains fully biodegradable.

[0067] The present invention does not impose any particular limitation on the source of the plasticizer, which can be self-made or purchased. The plasticizer can be prepared according to methods well known to those skilled in the art. In some specific embodiments, the plasticizer is prepared from 1,2-propanediol and di-n-hexanoic acid as raw materials through an esterification reaction in the presence of tetrabutyl titanate as a catalyst.

[0068] The molecular weight of the PPA is preferably 3000~10000 g / mol.

[0069] The content of the crosslinking agent is 0.05 to 0.3 parts, preferably 0.1 to 0.3 parts. In some specific embodiments, the content of the crosslinking agent is 0.1, 0.2 or 0.3 parts, or any of the above values ​​are the upper or lower limits.

[0070] Using BIBP as a crosslinking agent can induce a melt crosslinking reaction with the molecular chains of PBAT and PPC during twin-screw extrusion, thereby improving the compatibility of PBAT and PPC and effectively increasing the tensile elongation at break of the film, thus solving the problem of insufficient aging resistance of PBAT / PPC films.

[0071] The content of talc powder is 0.1 to 10 parts, preferably 4 to 10 parts. In some specific embodiments, the content of talc powder is 4, 5, 6, 7, 8, 9 or 10 parts, or any of the above values ​​are the upper or lower limits.

[0072] Talc can improve the tensile strength of films, enhance processing fluidity, and reduce film costs.

[0073] The lubricant is preferably pentaerythritol stearate (PETS).

[0074] The content of the lubricant is 0.1 to 2 parts, preferably 0.5 to 1.5 parts. In some specific embodiments, the content of the lubricant is 0.5, 1 or 1.5 parts, or any of the above values ​​are the upper or lower limits.

[0075] Lubricant PETS is beneficial for the extrusion of modified blown film resins and the blown film processing, improving the surface smoothness of the film, and also has multiple functions as an antistatic agent, lubricant, dispersant and antifogging agent.

[0076] The opening agent is preferably erucamide (EA) or oleamide.

[0077] The content of the opening agent is 0.1 to 1 part, preferably 0.5 to 1 part. In some specific embodiments, the content of the opening agent is 0.5, 0.6, 0.7, 0.8, 0.9 or 1 part, or any of the above values ​​are the upper or lower limits.

[0078] Opening agents can improve the opening properties of films and prevent the two layers of blown films from sticking together during the blown film traction roller winding process.

[0079] The antioxidant is preferably triethylene glycol bis[β-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate] (antioxidant 245).

[0080] The antioxidant content is 0.1 to 1 part, preferably 0.1 to 0.5 parts. In some specific embodiments, the antioxidant content is 0.1, 0.2, 0.3, 0.4 or 0.5 parts, or any of the above values ​​may be the upper or lower limit.

[0081] Antioxidants can improve the anti-aging properties of mulch films.

[0082] The UV stabilizer is preferably bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate (UV stabilizer 770).

[0083] The content of the UV-resistant agent is 0.1 to 1 part, preferably 0.2 to 0.5 parts. In some specific embodiments, the content of the UV-resistant agent is 0.1, 0.2, 0.3, 0.4 or 0.5 parts, or any of the above values ​​may be the upper or lower limit.

[0084] UV stabilizers can improve the UV resistance of plastic film and extend its service life.

[0085] The light stabilizer is preferably poly(4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol) ester (light stabilizer LS-622).

[0086] The content of the light stabilizer is 0.1 to 1 part, preferably 0.3 to 0.8 parts. In some specific embodiments, the content of the light stabilizer is 0.3, 0.4, 0.5, 0.6, 0.7 or 0.8 parts, or any of the above values ​​as the upper or lower limit.

[0087] Light stabilizers can capture free radicals in materials, block the chain reaction of light and oxygen aging, prevent free radicals from continuing to damage the molecular chain, effectively protect polymers, avoid problems such as yellowing, reduced gloss and weakened physical properties, and enhance the weather resistance of products.

[0088] The anti-hydrolysis agent is preferably polycarbodiimide.

[0089] The content of the anti-hydrolysis agent is 0.1 to 1 part, preferably 0.2 to 0.8 parts. In some specific embodiments, the content of the anti-hydrolysis agent is 0.2, 0.3, 0.4, 0.5, 0.6, 0.7 or 0.8 parts, or any of the above values ​​as the upper or lower limit.

[0090] Anti-hydrolysis agents can improve the hydrolysis resistance of mulch film, prevent PBAT from degrading under the action of water vapor and causing the mulch film to break, and extend the service life of the mulch film.

[0091] The nucleating agent is preferably a 1,3,5-benzenetricarboxamide derivative (N,N'-bis(benzoyl) sebacate dihydrazide) (nucleating agent TMC-300).

[0092] The nucleating agent content is 0.1 to 1 part, preferably 0.1 to 0.5 parts. In some specific embodiments, the nucleating agent content is 0.1, 0.2, 0.3, 0.4 or 0.5 parts, or any of the above values ​​as the upper or lower limit.

[0093] Nucleating agents can improve the crystallinity of PBAT, reduce crystal size, shorten crystallization time, and increase the tensile strength of the film.

[0094] The thickness of the tear-resistant, high-barrier, biodegradable mulch film provided by the present invention is preferably 8-12 μm.

[0095] Experimental results show that the biodegradable mulch film provided by this invention has a transverse tensile strength greater than 21 MPa, a longitudinal tensile strength greater than 24 MPa, a transverse elongation at break greater than 350%, a longitudinal elongation at break greater than 308%, a transverse right-angle tear strength greater than 116 KN / m, a longitudinal tear strength greater than 113116 KN / m, and a water vapor transmission rate greater than 120 g / m³. 2 •day.

[0096] This invention provides a method for preparing the above-mentioned tear-resistant, high-barrier, biodegradable mulch film, comprising the following steps:

[0097] Polybutylene adipate terephthalate, polypropylene carbonate, plasticizer, crosslinking agent, talc, lubricant, opening agent, antioxidant, UV stabilizer, light stabilizer, anti-hydrolysis agent, and nucleating agent are mixed to obtain a premix.

[0098] The above premixed material is extruded, granulated, and blown into a film to obtain a tear-resistant, high-barrier, biodegradable mulch film.

[0099] The present invention does not impose any special limitation on the extrusion granulation method, and can be any applicable extrusion granulation method known to those skilled in the art. In some specific embodiments, the premix is ​​added from the feed port of a twin-screw extruder, and after melt extrusion, water cooling, pelletizing, and drying, modified blown film special resin particles are obtained.

[0100] The preferred conditions for the extrusion granulation are:

[0101] The set temperatures for the twin-screw extruder are: Zone 1: 120-140℃, Zone 2: 150-170℃, Zone 3: 160-180℃, Zone 4: 170-190℃, Zone 5: 170-190℃, Zone 6: 170-190℃, Zone 7: 170-190℃, Zone 8: 170-190℃, Die head: 170-190℃, Screw speed: 100-300 rpm. The set temperatures for the blown film extruder are: Zone 1: 155-160℃, Zone 2: 165-170℃, Zone 3: 165-180℃, Zone 4: 165-180℃, Zone 5: 160-175℃, Main screw speed: 50-300 rpm, Traction speed: 10-50 m / min, Blow-up ratio: 2-4.

[0102] The film is then blown into a membrane using a blown film extrusion machine to obtain a biodegradable film.

[0103] The present invention does not impose special limitations on the blown film process, and can use blown film methods well known to those skilled in the art, such as blown film in a blown film machine. The present invention does not impose special limitations on the parameters of the blown film machine, and those skilled in the art can set them based on experience.

[0104] To further illustrate the present invention, a detailed description is provided below with reference to embodiments. However, it should be understood that these descriptions are merely for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims.

[0105] There are no particular restrictions on the source of any raw materials used in this invention; they can be purchased from the market or prepared using conventional methods known to those skilled in the art.

[0106] In the following examples, PBAT was purchased from Xinjiang Lanshan Tunhe Polyester Co., Ltd., model TH801T; PPC was provided by the Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, with a weight-average molecular weight of 3.0 × 10⁵ g / mol; the plasticizer, poly(1,2-propanediol adipate), was prepared from 1,2-propanediol and di-n-hexanoic acid as raw materials through esterification reaction under the action of tetrabutyl titanate catalyst, with a number-average molecular weight of 3000~10000 g / mol, and was provided by the Changchun Institute of Applied Chemistry, Chinese Academy of Sciences. The crosslinking agent was 1,4-di-tert-butylperoxide diisopropylbenzene, purchased from Dongguan Huanzong Trading Co., Ltd. Talc was purchased from Liaoning Jinghua New Materials Co., Ltd., model SK-98. The lubricant was pentaerythritol stearate, purchased from Jiangsu Sixin Interface Agent Technology Co., Ltd. The opening agent was erucamide or oleamide, purchased from Jiangxi Weike Oil & Chemical Co., Ltd. The antioxidant is triethylene glycol bis[β-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate], purchased from Nanjing Hualimingke Industry and Trade Co., Ltd.; the UV stabilizer is bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, purchased from Nanjing Hualimingke Industry and Trade Co., Ltd.; the light stabilizer is poly(4-hydroxy-2,2,6,6-tetramethyl-1-piperidinol) ester, purchased from Nanjing Hualimingke Industry and Trade Co., Ltd.; the hydrolysis stabilizer is polycarbodiimide, purchased from Nanjing Baitong New Materials Co., Ltd.; and the nucleating agent is 1,3,5-benzenetricarboxamide derivative (N,N'-bis(benzoyl) sebacate dihydrazide), brand name TMC-300, purchased from Shanxi Provincial Chemical Research Institute.

[0107] In the following examples, the tensile strength and elongation at break of the film were tested according to GB / T 1010.3-2006; the tear strength was tested according to QB / T 1130-91; and the water vapor transmission rate was tested according to ASTM E96-95.

[0108] All parts in the following examples are by weight.

[0109] Example 1

[0110] The weight proportions of each ingredient in the formula are as follows:

[0111] 70 copies of PBAT;

[0112] 20.3 copies of PPC;

[0113] Crosslinking agent 0.2 parts;

[0114] 4 parts talcum powder;

[0115] 2 parts plasticizer;

[0116] 1 part lubricant;

[0117] 0.8 parts of opening agent;

[0118] Antioxidant 0.3 parts;

[0119] 0.2 parts of UV protectant;

[0120] 0.5 parts light stabilizer;

[0121] 0.5 parts of anti-hydrolysis agent;

[0122] Nucleating agent 0.2 parts.

[0123] Weigh out PBAT, PPC, crosslinking agent, talc, lubricant, opening agent, plasticizer, antioxidant, UV stabilizer, light stabilizer, anti-hydrolysis agent, and nucleating agent according to the above formula. Mechanically blend each component for 5 minutes. Add the mixed raw material to a twin-screw extruder. The extrusion granulation conditions are as follows: Twin-screw extruder set temperature: Zone 1: 120-140℃, Zone 2: 150-170℃, Zone 3: 160-180℃, Zone 4: 170-190℃, Zone 5: 170-190℃, Zone 6: 170-190℃, Zone 7: 170-190℃, Zone 8: 170-190℃, Die head: 170-190℃, Screw speed: 100-300 rpm. The blown film machine was set to the following temperatures: Zone 1: 155-160℃, Zone 2: 165-170℃, Zone 3: 165-180℃, Zone 4: 165-180℃, Zone 5: 160-175℃; main screw speed: 50-300 rpm; traction speed: 10-50 m / min; blow-up ratio: 2-4. The film thickness was controlled at 8-12 μm. The mechanical properties and water vapor transmission rate of the film were tested, and the test results are listed in Table 1.

[0124] Example 2

[0125] The weight proportions of each ingredient in the formula are as follows:

[0126] 60 copies of PBAT;

[0127] 30.2 copies of PPC;

[0128] Crosslinking agent 0.3 parts;

[0129] 4 parts talcum powder;

[0130] 2 parts plasticizer;

[0131] 1 part lubricant;

[0132] 0.8 parts of opening agent;

[0133] Antioxidant 0.3 parts;

[0134] 0.2 parts of UV protectant;

[0135] 0.5 parts light stabilizer;

[0136] 0.5 parts of anti-hydrolysis agent;

[0137] Nucleating agent 0.2 parts.

[0138] Weigh out PBAT, PPC, crosslinking agent, talc, lubricant, opening agent, plasticizer, antioxidant, UV stabilizer, light stabilizer, anti-hydrolysis agent, and nucleating agent according to the above formula. Mechanically blend each component for 5 minutes. Add the mixed raw material to a twin-screw extruder. The extrusion granulation and blown film processes are the same as in Example 1. The film thickness is controlled at 8-12 μm. Test the mechanical properties and water vapor transmission of the film. The test results are listed in Table 1.

[0139] Example 3

[0140] The weight proportions of each ingredient in the formula are as follows:

[0141] 75 copies of PBAT;

[0142] 15.3 copies of PPC;

[0143] Crosslinking agent 0.3 parts;

[0144] 4 parts talcum powder;

[0145] 2 parts plasticizer;

[0146] 1 part lubricant;

[0147] 0.8 parts of opening agent;

[0148] Antioxidant 0.3 parts;

[0149] 0.4 parts of UV protectant;

[0150] 0.5 parts light stabilizer;

[0151] 0.2 parts of anti-hydrolysis agent;

[0152] Nucleating agent 0.2 parts.

[0153] The extrusion granulation and blown film processes in this step are the same as in Example 1. The film thickness is controlled at 8-12 μm. The mechanical properties and water vapor transmission rate of the film are tested, and the test results are listed in Table 1.

[0154] Example 4

[0155] The weight proportions of each ingredient in the formula are as follows:

[0156] 75 copies of PBAT;

[0157] 10 PPC copies;

[0158] Crosslinking agent 0.3 parts;

[0159] 9 parts talcum powder;

[0160] 2 parts plasticizer;

[0161] 1 part lubricant;

[0162] 0.8 parts of opening agent;

[0163] Antioxidant 0.3 parts;

[0164] 0.2 parts of UV protectant;

[0165] 0.5 parts light stabilizer;

[0166] 0.7 parts of anti-hydrolysis agent;

[0167] Nucleating agent 0.2 parts.

[0168] The extrusion granulation and blown film processes in this step are the same as in Example 1. The film thickness is controlled at 8-12 μm. The mechanical properties and water vapor transmission rate of the film are tested, and the test results are listed in Table 1.

[0169] Example 5

[0170] The weight proportions of each ingredient in the formula are as follows:

[0171] 68 PBATs;

[0172] 20 PPC copies;

[0173] Crosslinking agent 0.3 parts;

[0174] 6.2 parts talc;

[0175] 2 parts plasticizer;

[0176] 1 part lubricant;

[0177] 0.8 parts of opening agent;

[0178] Antioxidant 0.3 parts;

[0179] 0.2 parts of UV protectant;

[0180] 0.5 parts light stabilizer;

[0181] 0.5 parts of anti-hydrolysis agent;

[0182] Nucleating agent 0.2 parts.

[0183] The extrusion granulation and blown film processes in this step are the same as in Example 1. The film thickness is controlled at 8-12 μm. The mechanical properties and water vapor transmission rate of the film are tested, and the test results are listed in Table 1.

[0184] Example 6

[0185] The weight proportions of each ingredient in the formula are as follows:

[0186] 65 copies of PBAT;

[0187] 25 PPC copies;

[0188] Crosslinking agent 0.3 parts;

[0189] 4.2 parts talc;

[0190] 2 parts plasticizer;

[0191] 1 part lubricant;

[0192] 0.8 parts of opening agent;

[0193] Antioxidant 0.3 parts;

[0194] 0.2 parts of UV protectant;

[0195] 0.5 parts light stabilizer;

[0196] 0.5 parts of anti-hydrolysis agent;

[0197] Nucleating agent 0.2 parts.

[0198] The extrusion granulation and blown film processes in this step are the same as in Example 1. The film thickness is controlled at 8-12 μm. The mechanical properties and water vapor transmission rate of the film are tested, and the test results are listed in Table 1.

[0199] Comparative Example 1

[0200] The components and proportions, extrusion granulation and blown film processes are the same as in Example 1, except that the plasticizer is replaced with isosorbide dihexanoate.

[0201] The film thickness was controlled at 8-12 μm. The mechanical properties and water vapor transmission rate of the film were tested, and the test results are listed in Table 1.

[0202] Comparative Example 2

[0203] The components and proportions, extrusion granulation, and blown film processes are the same as in Example 1, except that no crosslinking agent is added.

[0204] Comparative Example 3

[0205] The components and proportions, extrusion granulation and blown film processes are the same as in Example 1, except that the crosslinking agent is replaced with dicumyl peroxide (DCP).

[0206] The film thickness was controlled at 8-12 μm. The mechanical properties and water vapor transmission rate of the film were tested, and the test results are listed in Table 1.

[0207] Table 1. Test results of mechanical properties of thin films

[0208]

[0209] As can be seen from the above results, the film prepared by the blown film resin provided by the present invention has high tensile strength and right-angle tear strength, and the tensile elongation at break is more than 350% in the transverse direction and more than 300% in the longitudinal direction, which can meet the requirements of mulch film use.

[0210] The analysis and test results show that as the PPC content increases, the water vapor transmission gradually decreases, resulting in better barrier properties, extended service life of the mulch film, and improved soil moisture retention. Comparing Example 1 and Comparative Example 1, it can be found that because the plasticizer PPA has a higher molecular weight, it exhibits higher tensile strength and right-angle tear strength than isosorbide dihexanoate, and lower migration rate, resulting in lower water vapor transmission in the film, making it more suitable as a plasticizer for mulch films. Comparing Example 1 and Comparative Example 2, it can be found that compared to the film without crosslinking agent BIBP, the mulch film with added crosslinking agent BIBP exhibits higher tensile strength, elongation at break, and right-angle tear strength, lower water vapor transmission, stronger barrier properties, and superior overall performance. Comparing Example 1 and Comparative Example 3, it can be found that the mulch film with added crosslinking agent BIBP has higher tensile strength, elongation at break, and right-angle tear strength compared to that with added crosslinking agent DCP. Its water vapor permeability is also lower, and its barrier properties are stronger, indicating that BIBP has a better crosslinking effect. Furthermore, it was found during the processing that DCP has a more unpleasant odor and is not suitable as an additive for mulch films. The BIBP used in this invention has no odor and is more suitable as an additive for mulch films.

[0211] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A tear-resistant, high-barrier, biodegradable mulch film, prepared from raw materials comprising the following parts by weight: 60-90 parts of polybutylene adipate-terephthalate; 10-40 parts of polypropylene carbonate; Plasticizer 0.5-5 parts; Crosslinking agent 0.05~0.3 parts; Talc powder 0.1~10 parts; Lubricant 0.1~2 parts; 0.1 to 1 part of opening agent; Antioxidant 0.1 to 1 part; 0.1 to 1 part of UV protectant; Light stabilizer 0.1 to 1 part; Anti-hydrolysis agent 0.1~1 part; Nucleating agent 0.1~1 part; The plasticizer is poly(1,2-propanediol adipate); The crosslinking agent is 1,4-di-tert-butylperoxide diisopropylbenzene.

2. The tear-resistant, high-barrier, biodegradable mulch film according to claim 1, characterized in that, The content of polybutylene adipate-terephthalate is 60-75 parts; The content of the polypropylene carbonate is 10-35 parts; The content of the plasticizer is 1 to 3 parts; The content of the crosslinking agent is 0.1 to 0.3 parts.

3. The tear-resistant, high-barrier, biodegradable mulch film according to claim 1, characterized in that, The lubricant is pentaerythritol stearate; The content of the lubricant is 0.5 to 1.5 parts.

4. The tear-resistant, high-barrier, biodegradable mulch film according to claim 1, characterized in that, The opening agent is erucamide or oleamide; The content of the opening agent is 0.5 to 1 part.

5. The tear-resistant, high-barrier, biodegradable mulch film according to claim 1, characterized in that, The antioxidant is triethylene glycol bis[β-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate]; The antioxidant content is 0.1 to 0.5 parts.

6. The tear-resistant, high-barrier, biodegradable mulch film according to claim 1, characterized in that, The UV stabilizer is bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate; The content of the UV-resistant agent is 0.2 to 0.5 parts.

7. The tear-resistant, high-barrier, biodegradable mulch film according to claim 1, characterized in that, The light stabilizer is poly(4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol) ester; The content of the light stabilizer is 0.3 to 0.8 parts.

8. The tear-resistant, high-barrier, biodegradable mulch film according to claim 1, characterized in that, The anti-hydrolysis agent is polycarbodiimide; The content of the anti-hydrolysis agent is 0.2 to 0.8 parts.

9. The tear-resistant, high-barrier, biodegradable mulch film according to claim 1, characterized in that, The nucleating agent is a 1,3,5-benzenetricarboxamide derivative (N,N'-bis(benzoyl) sebacate dihydrazide); The nucleating agent content is 0.1 to 0.5 parts.

10. A method for preparing the tear-resistant, high-barrier, biodegradable mulch film according to any one of claims 1 to 9, comprising the following steps: Polybutylene adipate terephthalate, polypropylene carbonate, plasticizer, crosslinking agent, talc, lubricant, opening agent, antioxidant, UV stabilizer, light stabilizer, anti-hydrolysis agent, and nucleating agent are mixed to obtain a premix. The above premixed material is extruded, granulated, and blown into a film to obtain a tear-resistant, high-barrier, biodegradable mulch film.

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