A biodegradable membrane, its preparation method and application

Abstract

This invention belongs to the field of biodegradable plastics technology, and provides a biodegradable film, its preparation method, and its applications. The biodegradable film of this invention, based on 100 parts by weight of raw materials, includes 74-99.998 parts of biodegradable polyester; 0.001-15 parts of eucommia gum; 0-2 parts of compatibilizer; 0.001-2 parts of opening agent; 0-2 parts of coupling agent; 0-2 parts of dispersant; and 0-8 parts of color masterbatch. Using biodegradable polyester as the raw material and eucommia gum as the functional additive, this invention results in a biodegradable film with excellent UV aging resistance, mechanical properties, barrier properties, and processing performance; it can significantly extend the safe period of crop mulching and can adapt to different soil conditions and agricultural operations. The resulting biodegradable film is green and safe during processing and use, and can be used not only in agricultural mulch films but also in shopping bags, garbage bags, food packaging, vegetable greenhouse films, injection-molded sheets, and injection-molded plates.

Description

Technical Field

[0001] This invention relates to the field of biodegradable plastics technology, and in particular to a biodegradable membrane, its preparation method, and its application. Background Technology

[0002] Biodegradable plastics possess good mechanical properties, high ductility and elongation at break, and excellent biodegradability. After use, they can be utilized by microorganisms in the environment and decomposed into carbon dioxide and water, effectively preventing environmental pollution. Therefore, biodegradable plastics are considered ideal alternatives to traditional plastics such as polyethylene and polystyrene and have become a research hotspot in the field of materials science.

[0003] Plastic mulch film is an important agricultural production material, playing a vital role in increasing crop yields, improving crop quality, and enriching the supply structure of agricultural products. However, due to prolonged exposure to the outdoors, including sun and rain, plastic mulch film is prone to aging and becoming brittle, leading to a sharp decline in its elongation at break. This manifests primarily as holes and cracks, rendering it ineffective and unable to meet the lifespan requirements during the crop growing season, thus failing to achieve its intended functional effects. The expected lifespan of biodegradable film is generally 1-6 months. Without anti-UV aging and anti-oxidation measures, it will break and fail during the planting season, significantly impacting its mechanical, barrier, and heat-insulating properties.

[0004] The application of UV stabilizers can effectively alleviate the problem of premature degradation due to aging of biodegradable membranes during use. Current technologies mainly involve adding inorganic UV stabilizers (mostly metal oxides or ceramic powders, such as nano-TiO2, ZnO, etc.) and organic UV stabilizers (including benzotriazoles, hindered amines, benzophenones, benzoic acid esters, and other organic compounds), sometimes supplemented with antioxidants (amines, phenols, thioesters, and phosphites, etc.). However, inorganic UV stabilizers in existing technologies are prone to aggregation and discoloration during the preparation of biodegradable membranes, severely affecting UV absorption. Organic UV stabilizers cannot provide full-spectrum sun protection, and some small molecules may exhibit poor thermal stability, easy migration, and easy decomposition, failing to effectively solve the problem of premature degradation. Furthermore, biodegradable membranes can degrade in situ in farmland soil environments, releasing additives into the soil and posing environmental risks. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a biodegradable membrane, its preparation method, and its application. The biodegradable membrane of this invention can solve the problem of premature degradation, and has excellent barrier and mechanical properties, while also being safe to degrade.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] This invention provides a biodegradable membrane, comprising the following components in parts by weight, based on 100 parts by weight of the raw materials used in its preparation:

[0008] 74~99.998 parts by weight of biodegradable polyester;

[0009] Eucommia gum 0.001~15 parts by weight;

[0010] 0-2 parts by weight of compatibilizer;

[0011] Opening agent: 0.001~2 parts by weight;

[0012] 0-2 parts by weight of coupling agent;

[0013] Dispersant 0-2 parts by weight;

[0014] Color masterbatch 0-8 parts by weight.

[0015] Preferably, the biodegradable polyester comprises one or a mixture of several of polybutylene adipate / terephthalate (PBAT), polybutylene succinate (PBS), polylactic acid (PLA), polypropylene carbonate (PPC), polyhydroxyalkanoate (PHA), polycaprolactone (PCL), polyvinyl alcohol (PVA), poly(β-hydroxybutyrate) (PHB), polyhydroxyvalerate (PHV), polyhydroxybutyrate-valerate copolyester (PHBV), and polyglycolic acid (PGA).

[0016] Preferably, the eucommia gum includes natural eucommia gum and / or synthetic eucommia gum.

[0017] Preferably, the eucommia gum is epoxidized eucommia gum;

[0018] The preparation method of the epoxidized Eucommia ulmoides gum includes the following steps:

[0019] Eucommia gum, peracetic acid, an acidic catalyst, and a nonpolar solvent are mixed and epoxy-modified to obtain the epoxidized eucommia gum.

[0020] The acidic catalyst is concentrated sulfuric acid;

[0021] The mass ratio of Eucommia ulmoides gum, peracetic acid, and acidic catalyst is 10~25:1~10:1~5;

[0022] The epoxy modification is performed at a temperature of 40-60℃ for 5-10 hours.

[0023] Preferably, the compatibilizer is a non-reactive compatibilizer or a reactive compatibilizer; the non-reactive compatibilizer includes one or a mixture of several of ethylene acrylate (EAA), ethylene-ethyl acrylate (EEA), and ethylene-vinyl acetate copolymer (EVA); the reactive compatibilizer includes one or a mixture of several of acid anhydride compatibilizers, epoxy compatibilizers, imine compatibilizers, carboxylic acid compatibilizers, oxazoline compatibilizers, and isocyanate compatibilizers.

[0024] Preferably, the opening agent is an organic opening agent and / or an inorganic opening agent; the organic opening agent includes one or a mixture of several of fatty acid amides, fatty acid esters, bis-stearamides, alkanes and siloxanes; the inorganic opening agent includes one or a mixture of several of talc, diatomaceous earth and silica.

[0025] The coupling agent is a silane coupling agent, which includes one or a mixture of several of KH550, KH560, KH570 and KH590.

[0026] The dispersant includes one or a mixture of stearic acid, oleic acid and titanate;

[0027] The color masterbatch does not contain polyolefins or other non-biodegradable polymers.

[0028] The present invention also provides a method for preparing the biodegradable membrane described in the above technical solution, comprising the following steps:

[0029] Biodegradable polyester, eucommia gum, compatibilizer, opening agent, coupling agent, dispersant and color masterbatch are mixed and then extruded, granulated and blown into a film to obtain the biodegradable film.

[0030] The present invention also provides a method for preparing the biodegradable membrane described in the above technical solution, comprising the following steps:

[0031] Biodegradable polyester and eucommia gum are mixed and then extruded and granulated sequentially to obtain masterbatch.

[0032] The masterbatch is mixed with compatibilizer, opening agent, coupling agent, dispersant and color masterbatch, and blown into a film to obtain the biodegradable mulch film.

[0033] The present invention also provides a method for preparing the biodegradable membrane described in the above technical solution, comprising the following steps:

[0034] A portion of biodegradable polyester and eucommia gum are mixed and then extruded and granulated sequentially to obtain masterbatch.

[0035] The masterbatch is mixed with the remaining biodegradable polyester, compatibilizer, opening agent, coupling agent, dispersant, and color masterbatch, and then blow-molded into a film to obtain the biodegradable film.

[0036] The present invention also provides the application of the biodegradable membrane described in the above technical solution or the biodegradable membrane prepared by the above technical solution in agricultural mulch film, vegetable greenhouse film, injection molded sheet, injection molded sheet, shopping bag, garbage bag and food packaging.

[0037] This invention provides a biodegradable membrane.

[0038] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0039] 1. This invention uses biodegradable polyester as raw material and eucommia gum as a functional additive, resulting in a biodegradable film with excellent UV aging resistance, mechanical properties, barrier properties, and processing performance. It can significantly extend the safe period of crop mulching and adapt to different soil conditions and agricultural operations. The resulting biodegradable film is green and safe during processing and use, and can be used not only in agricultural mulch films but also in shopping bags, garbage bags, food packaging, greenhouse films, injection-molded sheets, and injection-molded plates.

[0040] 2. The biodegradable membrane of the present invention is completely degradable and can be decomposed into carbon dioxide and water by microorganisms in the soil; it leaves no chemical additive residue, causes no secondary pollution, is environmentally friendly, does not require recycling, and can be directly plowed into the soil to increase soil organic matter content, improve soil structure, and help improve crop yield and quality.

[0041] 3. The biodegradable membrane of the present invention has excellent anti-ultraviolet aging properties. After artificial aging for 100 hours, the film product therein can still maintain good mechanical properties and barrier properties, and has good weather resistance.

[0042] 4. The biodegradable film of the present invention has excellent mechanical and barrier properties. Its film products can meet the mechanical property requirements of GB / T35795-2017 fully biodegradable agricultural ground cover film and the hygiene requirements of GB / T1004-2008 packaging plastic composite film. It can also effectively enhance water vapor barrier properties and can be used in food packaging and agricultural mulch film fields.

[0043] Furthermore, the eucommia gum is epoxidized eucommia gum, which further improves the UV resistance, barrier properties, and mechanical properties of the biodegradable membrane. Attached Figure Description

[0044] Figure 1 This is an image of the biodegradable membrane obtained in Comparative Example 1 before aging;

[0045] Figure 2 Images of the biodegradable membrane obtained in Example 1 after aging;

[0046] Figure 3The image shows the biodegradable membrane obtained in Comparative Example 1 after aging. Detailed Implementation

[0047] This invention provides a biodegradable mulch film, comprising the following components in parts by weight, based on 100 parts by weight of the raw materials used in its preparation:

[0048] 74~99.998 parts by weight of biodegradable polyester;

[0049] Eucommia gum 0.001~15 parts by weight;

[0050] 0-2 parts by weight of compatibilizer;

[0051] Opening agent: 0.001~2 parts by weight;

[0052] 0-2 parts by weight of coupling agent;

[0053] Dispersant 0-2 parts by weight;

[0054] Color masterbatch 0-8 parts by weight.

[0055] Unless otherwise specified, the raw materials used in this invention are preferably commercially available products.

[0056] Based on 100 parts by weight of raw materials, the biodegradable mulch film provided by this invention comprises 74-99.998 parts by weight of biodegradable polyester, more preferably 80-95 parts by weight, and specifically preferably 75 parts by weight, 80 parts by weight, 85 parts by weight, 88 parts by weight, 90 parts by weight, 91 parts by weight, 93 parts by weight, 95 parts by weight, 98 parts by weight, or 99 parts by weight. In this invention, the biodegradable polyester preferably comprises one or a mixture of several of the following: polybutylene adipate / terephthalate (PBAT), polybutylene succinate (PBS), polylactic acid (PLA), polypropylene carbonate (PPC), polyhydroxyalkanoate (PHA), polycaprolactone (PCL), polyvinyl alcohol (PVA), poly(β-hydroxybutyrate) (PHB), polyhydroxyvalerate (PHV), polyhydroxybutyrate-valerate copolyester (PHBV), and polyglycolic acid (PGA). The preferred step includes polybutylene adipate / terephthalate (PBAT) and / or polylactic acid (PLA), specifically preferably a mixture of polybutylene adipate / terephthalate (PBAT), polybutylene adipate / terephthalate and polylactic acid; the mass ratio of polybutylene adipate / terephthalate and polylactic acid in the mixture of polybutylene adipate / terephthalate and polylactic acid is preferably 4~8:1, specifically preferably 4.87:1, 5:1, 6:1, 7:1 or 7.38:1.

[0057] Based on 100 parts by weight of raw materials, the biodegradable mulch film provided by this invention includes 0.001 to 15 parts by weight of Eucommia ulmoides gum, specifically preferably 0.5 parts by weight, 1 part by weight, 2 parts by weight, 3 parts by weight, 4 parts by weight, 5 parts by weight, 6 parts by weight, 7 parts by weight, 8 parts by weight, 9 parts by weight, 10 parts by weight, 11 parts by weight, 12 parts by weight, 13 parts by weight, 14 parts by weight, or 15 parts by weight. In this invention, the Eucommia ulmoides gum preferably includes natural Eucommia ulmoides gum and / or synthetic Eucommia ulmoides gum, more preferably a mixture of natural Eucommia ulmoides gum and synthetic Eucommia ulmoides gum, wherein the mass ratio of natural Eucommia ulmoides gum to synthetic Eucommia ulmoides gum in the mixture is preferably 1 to 3:1, specifically preferably 2:1. Gutta-Pereha or Balata gum, also known as Eucommia gum, is a white, cottony solid found in the phloem, parenchyma, and vascular bundles of Eucommia leaves, bark, and samara fruits. After extraction, purification, and decolorization, it yields a white solid. Gutta-Pereha possesses the dual properties of rubber and plastic, exhibiting excellent flexibility and a low melting point, making it far more processable than conventional plastics. This characteristic facilitates its blending with other rubber or plastic materials. Generally, blending rubber with polyolefins (such as polyethylene and polypropylene) requires high temperatures and typically only yields thermoplastic elastomers; however, blending gutta-Pereha with plastics not only significantly reduces the mixing temperature but also improves the overall properties of the blend, showing marked improvements in fatigue resistance, barrier properties, and tear resistance. The main chemical component of Eucommia ulmoides gum is trans-1,4-polyisoprene. In its molecular structure, the methylene units are distributed on both sides of the C=C double bond, with a highly symmetrical atomic arrangement, which facilitates the regular molecular arrangement and embedding in the crystal structure. Eucommia ulmoides gum is solid at room temperature, exhibiting toughness and belonging to crystalline rigid plastics. Its density ranges from 0.95 to 0.98 g / cm³, and its average molecular weight is approximately 160,000 to 173,000 g / mol. Pure Eucommia ulmoides gum begins to crystallize at 10℃, softens and exhibits elastic behavior at 40-50℃, and is easily stretched; it softens further at 100℃, exhibiting significant plasticity, and can recover its original properties after cooling. X-ray diffraction (XRD) analysis shows that Eucommia ulmoides gum exists in two crystal forms: α-crystalline and β-crystalline, with melting points of 62℃ and 52℃, respectively. The α-crystalline form belongs to the monoclinic crystal system, space group P21 / c, and chain group P. C The unit cell parameter is a o =0.789nm, b o =0.629nm, c o =0.877nm, β=102°; the β-crystal form belongs to the orthorhombic crystal system, space group P212121, chain line group P1, and cell parameters a0=0.778nm, b0=1.178nm, c0=0.422nm. α =β = γ =90°. The characteristic absorption peaks of the infrared spectrum of Eucommia ulmoides gum mainly include 2920.4 cm⁻¹. -1 1079.83cm -1 and 1705.1cm -1 These vibrations are attributed to the asymmetric and symmetric stretching vibrations of the methylene group in the saturated hydrocarbon backbone, the stretching vibrations of the C=C functional group, and the deformation vibrations of the -CH2- and CH functional groups, respectively. Furthermore, its glass transition temperature is approximately -55℃, its tensile strength is approximately 15 MPa, and its Shore hardness is approximately 95A. Therefore, by doping an appropriate amount of Eucommia ulmoides gum into the biodegradable film, not only can its service life be extended, its UV aging resistance, mechanical properties, barrier properties, and processability improved, but its compatibility with polar biodegradable plastics such as polyester can also be effectively improved, achieving a comprehensive improvement in overall performance.

[0058] In this invention, the Eucommia ulmoides gum is further epoxidized Eucommia ulmoides gum. In this invention, the preparation method of the epoxidized Eucommia ulmoides gum preferably includes the following steps: mixing Eucommia ulmoides gum, peracetic acid, an acidic catalyst, and a non-polar solvent, and performing epoxy modification to obtain the epoxidized Eucommia ulmoides gum. In this invention, the purity of the Eucommia ulmoides gum is preferably ≥99%. In this invention, the acidic catalyst is preferably concentrated sulfuric acid, and the concentration of the concentrated sulfuric acid is preferably 98%. In this invention, the non-polar solvent preferably includes petroleum ether. In this invention, the mass ratio of Eucommia ulmoides gum, peracetic acid, and acidic catalyst is preferably 10~25:1~10:1~5, specifically preferably 18.5:3.5:1.5. In this invention, the mass ratio of Eucommia ulmoides gum and non-polar solvent is preferably 10~25:100. In this invention, the epoxy modification temperature is preferably 40~60℃, more preferably 50℃; the time is preferably 5~10h, more preferably 8h. After epoxy modification, the present invention preferably further includes: subjecting the obtained adhesive solution to anhydrous ethanol precipitation sequentially, and washing and drying the collected precipitate sequentially to obtain the epoxidized Eucommia ulmoides gum. Further, epoxidized Eucommia ulmoides gum introduces epoxy groups into the Eucommia ulmoides gum molecular chain through an epoxidation reaction, further improving its original properties (such as antioxidant properties, aging resistance, mechanical properties, compatibility, etc.). Its core feature is that epoxidized Eucommia ulmoides gum combines the elasticity of rubber with the rigidity of plastic, while improving compatibility with polar materials (such as polyester, resin, etc.), and exhibiting superior oil resistance and ozone resistance.

[0059] Based on 100 parts by weight of raw materials, the biodegradable mulch film provided by this invention includes 0-2 parts by weight of compatibilizer, preferably 0.001-2 parts by weight, and specifically preferably 0.1 parts by weight, 0.5 parts by weight, 1 part by weight, 1.5 parts by weight, or 2 parts by weight. In this invention, the compatibilizer is preferably a non-reactive compatibilizer or a reactive compatibilizer, more preferably a non-reactive compatibilizer. In this invention, the non-reactive compatibilizer preferably includes one or a mixture of several selected from ethylene acrylate (EAA), ethylene-ethyl acrylate (EEA), and ethylene-vinyl acetate copolymer (EVA). In this invention, the reactive compatibilizer includes one or a mixture of several selected from acid anhydride compatibilizers, epoxy compatibilizers, imine compatibilizers, carboxylic acid compatibilizers, oxazoline compatibilizers, and isocyanate compatibilizers.

[0060] Based on 100 parts by weight of raw materials, the biodegradable mulch film provided by this invention includes 0.001-2 parts by weight of an opening agent, preferably 0.1-2 parts by weight, and more specifically 0.5 parts by weight, 1 part by weight, 1.5 parts by weight, or 2 parts by weight. In this invention, the opening agent is preferably an organic opening agent and / or an inorganic opening agent. In this invention, the organic opening agent includes one or a mixture of several of fatty acid amides, fatty acid esters, bis-stearamides, alkanes, and siloxanes, more preferably fatty acid amides or bis-stearamides. In this invention, the fatty acid amide preferably includes erucamide and / or oleamide. In this invention, the bis-stearamide is preferably ethylene bis-stearamide (EBS). In this invention, the inorganic opening agent preferably includes one or a mixture of several of talc, diatomaceous earth, and silica.

[0061] Based on 100 parts by weight of raw materials, the biodegradable mulch film provided by this invention includes 0-2 parts by weight of coupling agent, preferably 0.001-2 parts by weight, and more specifically 0.1 parts by weight, 0.5 parts by weight, 1 part by weight, 1.5 parts by weight, or 2 parts by weight. In this invention, the coupling agent is preferably a silane coupling agent, which includes one or a mixture of several of KH550, KH560, KH570, and KH590.

[0062] Based on 100 parts by weight of raw materials, the biodegradable mulch film provided by the present invention includes 0-2 parts by weight of dispersant, preferably 0.001-2 parts by weight, and more specifically 0.1 parts by weight, 0.5 parts by weight, 1 part by weight, 1.5 parts by weight, or 2 parts by weight. In the present invention, the dispersant preferably includes one or a mixture of stearic acid, oleic acid, and titanate. In the present invention, when the dispersant is a mixture of oleic acid and titanate, the mass ratio of oleic acid to titanate is preferably 1:1.

[0063] Based on 100 parts by weight of raw materials, the biodegradable mulch film provided by this invention comprises 0-8 parts by weight of color masterbatch, preferably 0.001-8 parts by weight, specifically preferably 0.1 parts by weight, 0.5 parts by weight, 1 part by weight, 2 parts by weight, 3 parts by weight, 4 parts by weight, 5 parts by weight, 6 parts by weight, 7 parts by weight, or 8 parts by weight. This invention does not impose specific requirements on the color masterbatch; it can be selected according to actual needs. The color masterbatch does not contain polyolefins or other non-biodegradable polymers. In one specific embodiment of this invention, the color masterbatch is preferably carbon black, which does not contain polyolefins or other non-biodegradable polymers.

[0064] This invention uses Eucommia ulmoides gum to replace traditional chemical UV stabilizers and antioxidants to prepare biodegradable membranes. This not only improves the mechanical properties, barrier properties, and anti-aging properties of the biodegradable membranes, but also eliminates the use of toxic reagents in the preparation process, avoiding or reducing secondary pollution during use. It solves the problems of premature degradation, uncontrollable degradation, and poor barrier and mechanical properties of existing biodegradable membranes.

[0065] The present invention also provides a method for preparing the biodegradable mulch film described in the above technical solution, comprising the following steps:

[0066] Biodegradable polyester, eucommia gum, compatibilizer, opening agent, coupling agent, dispersant and color masterbatch are mixed and then extruded, granulated and blown into film to obtain the biodegradable mulch film.

[0067] In this invention, the biodegradable polyester is preferably dried before use, and the drying is preferably low-temperature drying or vacuum drying. This invention does not specifically limit the parameters of the low-temperature drying or vacuum drying, as long as the moisture content of the biodegradable polyester is less than 0.5%.

[0068] In this invention, the mixing is preferably carried out in a high-speed mixer.

[0069] In this invention, the extrusion molding and granulation are preferably carried out in an extrusion molding equipment.

[0070] In this invention, the granulation temperature is preferably 100~200℃, and more preferably 130~165℃ or 180~195℃.

[0071] In this invention, the temperature for blow molding is preferably 100~200℃, and more preferably 130~165℃ or 180~195℃.

[0072] This invention also provides another method for preparing the biodegradable mulch film described in the above technical solution, comprising the following steps:

[0073] Biodegradable polyester and eucommia gum are mixed and then extruded and granulated sequentially to obtain masterbatch.

[0074] The masterbatch is mixed with compatibilizer, opening agent, coupling agent, dispersant and color masterbatch, and blown into a film to obtain the biodegradable mulch film.

[0075] This invention involves mixing biodegradable polyester and eucommia gum, followed by extrusion molding and granulation to obtain a masterbatch. Preferably, the mixing is performed in a high-speed mixer. The extrusion molding and granulation are preferably performed in an extrusion molding machine. The granulation temperature is preferably 100-200°C, specifically 130-165°C or 180-195°C.

[0076] After obtaining the masterbatch, the present invention mixes the masterbatch with a compatibilizer, an opening agent, a coupling agent, a dispersant, and a color masterbatch, and then blow-moldes it into a film to obtain the biodegradable mulch film. In the present invention, the blow-molding temperature is preferably 100~200℃, and more preferably 130~165℃ or 180~195℃.

[0077] The present invention also provides another method for preparing the biodegradable mulch film, comprising the following steps:

[0078] A portion of biodegradable polyester and eucommia gum are mixed and then extruded and granulated sequentially to obtain masterbatch.

[0079] The masterbatch is mixed with the remaining biodegradable polyester, compatibilizer, opening agent, coupling agent, dispersant, and color masterbatch, and then blow-molded into a film to obtain the biodegradable mulch film.

[0080] This invention involves mixing partially biodegradable polyester and eucommia gum, followed by extrusion molding and granulation to obtain a masterbatch. Preferably, the mixing is performed in a high-speed mixer. The extrusion molding and granulation are preferably performed in an extrusion molding machine. The granulation temperature is preferably 100-200°C, specifically 130-165°C or 180-195°C.

[0081] After obtaining the masterbatch, the present invention mixes the masterbatch with the remaining biodegradable polyester, compatibilizer, opening agent, coupling agent, dispersant, and color masterbatch, and then blow-moldes the mixture to obtain the biodegradable mulch film. In the present invention, the blow-molding temperature is preferably 100~200℃, and more preferably 130~165℃ or 180~195℃.

[0082] The present invention also provides the application of the biodegradable membrane described in the above technical solution or the biodegradable membrane prepared by the above technical solution in agricultural mulch film, vegetable greenhouse film, injection molded sheet, injection molded sheet, shopping bag, garbage bag and food packaging.

[0083] The following detailed description, in conjunction with embodiments, illustrates the biodegradable membrane, its preparation method, and its applications provided by the present invention. However, these descriptions should not be construed as limiting the scope of protection of the present invention.

[0084] The preparation method of epoxidized Eucommia ulmoides gum used in the following examples is as follows:

[0085] Weigh 18.5 parts by weight of Eucommia ulmoides gum (purity ≥99%) and mix with 3.5 parts by weight of epoxidizing modifier peracetic acid, add 1.5 parts by weight of acidic catalyst concentrated sulfuric acid (98%) and 100 parts by weight of non-polar solvent petroleum ether, react at 50℃ for 8 hours, the resulting epoxidized gum solution is precipitated with anhydrous ethanol, the precipitate is washed and dried to obtain epoxidized Eucommia ulmoides gum.

[0086] Example 1

[0087] A biodegradable membrane, prepared from 100 parts by weight of raw materials, has the following composition:

[0088] 93.0 parts of polybutylene adipate / terephthalate (PBAT);

[0089] Epoxidized Eucommia ulmoides gum, 5.0 parts;

[0090] 0.5 parts compatibilizer;

[0091] 0.5 parts of opening agent;

[0092] 0.5 parts coupling agent;

[0093] 0.5 parts dispersant;

[0094] The epoxidized eucommia gum is obtained by epoxidizing natural eucommia gum; the compatibilizer is EVA; the opening agent is EBS; the coupling agent is KH550; and the dispersant is stearic acid.

[0095] The preparation method is as follows:

[0096] 1. Weigh 93.0 parts of PBAT and vacuum dry until the moisture content is below 0.5%;

[0097] 2. Weigh 5.0 parts of epoxidized Eucommia ulmoides gum, 0.5 parts of compatibilizer, 0.5 parts of opening agent, 0.5 parts of coupling agent, 0.5 parts of dispersant and 93.0 parts of PBAT and mix them. After stirring evenly in a high-speed mixer, the mixture is transferred to an extrusion molding equipment and extruded. After granulation and blow molding, a biodegradable membrane is obtained. The granulation and blow molding temperature is between 130 and 165℃. The thickness of the obtained biodegradable membrane is 10±0.5μm.

[0098] Example 2

[0099] A biodegradable membrane, prepared from 100 parts by weight of raw materials, has the following composition:

[0100] 88.0 parts of polybutylene adipate / terephthalate (PBAT);

[0101] Epoxidized Eucommia ulmoides gum, 10.0 parts;

[0102] 0.5 parts compatibilizer;

[0103] 0.5 parts of opening agent;

[0104] 0.5 parts coupling agent;

[0105] 0.5 parts dispersant;

[0106] The epoxidized Eucommia gum is obtained by epoxidation of natural Eucommia gum and synthetic Eucommia gum (mass ratio 2:1); the compatibilizer is EVA, the opening agent is EBS; the coupling agent is KH550; and the dispersant is oleic acid.

[0107] The preparation method is as follows:

[0108] 1. Weigh 88.0 parts of PBAT and dry at low temperature until the moisture content is below 0.5%;

[0109] 2. Weigh 10.0 parts of epoxidized Eucommia ulmoides gum, 0.5 parts of compatibilizer, 0.5 parts of opening agent, 0.5 parts of coupling agent, 0.5 parts of dispersant and 88.0 parts of PBAT and mix them. After stirring evenly in a high-speed mixer, the mixture is transferred to an extrusion molding equipment and extruded. After granulation and blow molding, a biodegradable membrane is obtained. The granulation and blow molding temperature is between 130 and 165℃. The thickness of the obtained biodegradable membrane is 10±0.5μm.

[0110] Alternative Solution 1: Weigh 20.0 parts of PBAT, mix with 10.0 parts of epoxidized eucommia gum, 0.5 parts of compatibilizer, 0.5 parts of opening agent, 0.5 parts of coupling agent, and 0.5 parts of dispersant. After mixing evenly with a high-speed mixer, transfer to an extrusion molding equipment to extrude and granulate to obtain eucommia gum / PBAT masterbatch. Then mix with 68.0 parts of PBAT and blow mold to form a film to obtain a biodegradable film. The granulation and blow molding temperatures are between 130 and 165°C.

[0111] Alternative Solution 2: Weigh 10.0 parts of epoxidized Eucommia ulmoides gum and mix with 88.0 parts of PBAT. After mixing evenly with a high-speed mixer, transfer the mixture to an extrusion molding equipment to granulate Eucommia ulmoides gum / PBAT granules. Then mix with 0.5 parts of compatibilizer, 0.5 parts of opening agent, 0.5 parts of coupling agent, and 0.5 parts of dispersant. After mixing evenly with a high-speed mixer, transfer the mixture directly to an extrusion molding equipment to blow-form a film to obtain a biodegradable film. The granulation and blow-forming temperatures are between 130 and 165°C.

[0112] Example 3

[0113] A biodegradable membrane, prepared from 100 parts by weight of raw materials, has the following composition:

[0114] 75.5 parts of polybutylene adipate / terephthalate (PBAT);

[0115] 15.5 parts of polylactic acid (PLA);

[0116] Epoxidized Eucommia ulmoides gum, 5.0 parts;

[0117] 0.5 parts compatibilizer;

[0118] 0.5 parts of opening agent;

[0119] 0.5 parts coupling agent;

[0120] 0.5 parts dispersant;

[0121] 2.0 parts of color masterbatch;

[0122] The epoxidized Eucommia ulmoides gum is obtained by epoxidation of synthetic Eucommia ulmoides gum; the compatibilizer is EAA; the opening agent is EBS; the coupling agent is KH570; the dispersant is titanate; the color masterbatch is carbon black, and it does not contain polyolefins or other non-biodegradable polymers.

[0123] The preparation method is as follows:

[0124] 1. Weigh 75.5 parts PBAT and 15.5 parts PLA, and dry them at low temperature until the moisture content is below 0.5%;

[0125] 2. Weigh 5.0 parts of epoxidized Eucommia ulmoides gum, 0.5 parts of compatibilizer, 0.5 parts of opening agent, 0.5 parts of coupling agent, 0.5 parts of dispersant, 2.0 parts of color masterbatch, and mix with biodegradable polyester (75.5 parts of PBAT and 15.5 parts of PLA). After stirring evenly with a high-speed mixer, the mixture is transferred to an extrusion molding equipment and extruded. After granulation and blow molding, a biodegradable film is obtained. The granulation and blow molding temperature is between 180 and 195℃, and the thickness of the obtained biodegradable film is 10±0.5μm.

[0126] Example 4

[0127] A biodegradable membrane, prepared from 100 parts by weight of raw materials, has the following composition:

[0128] 77.5 parts of polybutylene adipate / terephthalate (PBAT);

[0129] 10.5 parts of polylactic acid (PLA);

[0130] Epoxidized Eucommia ulmoides gum, 10.0 parts;

[0131] 0.5 parts compatibilizer;

[0132] 0.5 parts of opening agent;

[0133] 0.5 parts coupling agent;

[0134] 0.5 parts dispersant;

[0135] The epoxidized Eucommia gum is obtained by epoxidation of natural Eucommia gum and synthetic Eucommia gum (mass ratio 2:1); the compatibilizer is EEA; the opening agent is erucamide; the coupling agent is KH560; and the dispersant is a mixture of oleic acid and titanate (mass ratio 1:1).

[0136] The preparation method is as follows:

[0137] 1. Weigh 77.5 parts of PBAT and 10.5 parts of PLA, and dry them at low temperature until the moisture content is below 0.5%;

[0138] 2. Weigh 10.0 parts of epoxidized Eucommia ulmoides gum, 0.5 parts of compatibilizer, 0.5 parts of opening agent, 0.5 parts of coupling agent, 0.5 parts of dispersant and biodegradable polyester (77.5 parts of PBAT and 10.5 parts of PLA) and mix them. After stirring evenly in a high-speed mixer, the mixture is transferred to an extrusion molding equipment and extruded. After granulation and blow molding, a biodegradable film is obtained. The granulation and blow molding temperature is between 180 and 195℃. The thickness of the obtained biodegradable film is 10±0.5μm.

[0139] Alternative Solution 1: Weigh 77.5 parts PBAT, 10.5 parts PLA, and 10.0 parts epoxidized Eucommia ulmoides gum. After mixing evenly with a high-speed mixer, transfer the mixture to an extrusion molding equipment to extrude and granulate it to obtain Eucommia ulmoides gum / PBAT / PLA masterbatch. Then mix it with 0.5 parts compatibilizer, 0.5 parts opening agent, 0.5 parts coupling agent, and 0.5 parts dispersant, and blow mold it into a film to obtain a biodegradable film. The granulation and blow molding temperatures are between 180 and 195°C.

[0140] Alternative Solution 2: Weigh 10.0 parts of epoxidized Eucommia ulmoides gum, 10.5 parts of PLA and 20.5 parts of PBAT, mix them evenly with a high-speed mixer, and then transfer them to an extrusion molding equipment to extrude and granulate them to obtain Eucommia ulmoides gum / PBAT / PLA masterbatch. Then mix it with 57.0 parts of PBAT, 0.5 parts of compatibilizer, 0.5 parts of opening agent, 0.5 parts of coupling agent and 0.5 parts of dispersant, mix it evenly with a high-speed mixer, and then directly transfer it to an extrusion molding equipment to blow mold a film to obtain a biodegradable film. The granulation and blow molding temperature is between 180 and 195℃.

[0141] Example 5

[0142] The difference from Example 1 is that epoxidized Eucommia gum is replaced with natural Eucommia gum, otherwise it is the same as Example 1.

[0143] Example 6

[0144] The difference from Example 1 is that the weight of epoxidized Eucommia ulmoides gum was adjusted to 10 parts by weight, and the weight of PBAT was adjusted to 88.0 parts by weight. The rest is the same as in Example 1.

[0145] Example 7

[0146] The difference from Example 1 is that the weight of epoxidized Eucommia ulmoides gum was adjusted to 12.0 parts, and the weight of PBAT was adjusted to 86.0 parts, otherwise the same as in Example 1.

[0147] Example 8

[0148] The difference from Example 6 is that epoxidized Eucommia gum is replaced with natural Eucommia gum, otherwise it is the same as Example 6.

[0149] Comparative Example 1

[0150] A biodegradable membrane, prepared from 100 parts by weight of raw materials, has the following composition:

[0151] 98.0 parts of polybutylene adipate / terephthalate (PBAT);

[0152] 0.5 parts compatibilizer;

[0153] 0.5 parts of opening agent;

[0154] 0.5 parts coupling agent;

[0155] 0.5 parts dispersant;

[0156] The compatibilizer is EVA; the opening agent is EBS; the coupling agent is KH550; and the dispersant is stearic acid.

[0157] The preparation method is as follows:

[0158] 1. Weigh 98.0 parts of PBAT and dry at low temperature until the moisture content is below 0.5%;

[0159] 2. Weigh 0.5 parts compatibilizer, 0.5 parts opening agent, 0.5 parts coupling agent, 0.5 parts dispersant and 98.0 parts PBAT and mix them. After stirring evenly in a high-speed mixer, the mixture is transferred to an extrusion molding equipment and extruded. After granulation and blow molding, a biodegradable membrane is obtained. The granulation and blow molding temperature is between 130 and 165℃. The thickness of the obtained biodegradable membrane is 10±0.5μm.

[0160] Comparative Example 2

[0161] A biodegradable membrane, prepared from 100 parts by weight of raw materials, has the following composition:

[0162] 80.5 parts of polybutylene adipate / terephthalate (PBAT);

[0163] 15.5 parts of polylactic acid (PLA);

[0164] 0.5 parts compatibilizer;

[0165] 0.5 parts of opening agent;

[0166] 0.5 parts coupling agent;

[0167] 0.5 parts dispersant;

[0168] 2.0 parts of color masterbatch;

[0169] The compatibilizer is EAA; the opening agent is EBS; the coupling agent is KH570; the dispersant is titanate; the color masterbatch is carbon black, and it does not contain polyolefins or other non-biodegradable polymers.

[0170] The preparation method is as follows:

[0171] 1. Weigh 90.5 parts of PBAT and dry at low temperature until the moisture content is below 0.5%;

[0172] 2. Weigh 90.5 parts PBAT, 15.5 parts PLA, 0.5 parts compatibilizer, 0.5 parts opening agent, 0.5 parts coupling agent, 0.5 parts dispersant and 2 parts color masterbatch and mix them. After stirring evenly in a high-speed mixer, the mixture is transferred to an extrusion molding equipment and extruded. After granulation and blow molding, a biodegradable film is obtained. The granulation and blow molding temperature is between 180 and 195℃. The thickness of the obtained biodegradable film is 10±0.5μm.

[0173] Comparative Example 3

[0174] The difference from Example 1 is that epoxidized Eucommia ulmoides gum is replaced with epoxidized natural rubber, otherwise it is the same as Example 1.

[0175] Comparative Example 4

[0176] The difference from Comparative Example 4 is that the epoxidized natural rubber is replaced with natural rubber, otherwise it is the same as Comparative Example 4.

[0177] Comparative Example 5

[0178] The difference from Example 1 is that the epoxidized Eucommia ulmoides gum is replaced with an organic UV stabilizer, benzotriazole, specifically UV-327 (2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole), otherwise it is the same as Example 1.

[0179] Mechanical properties were tested using GB / T 35795-2017 fully biodegradable agricultural ground cover film, and water vapor transmission rate was tested using GB / T1004-2008 plastic composite film for packaging.

[0180] The aging conditions were as follows: artificial climate aging performance test was conducted according to GB / T 35795-2017 for fully biodegradable agricultural ground cover films, and the test duration was 100 hours.

[0181] The performance changes of the biodegradable membranes obtained in the examples and comparative examples before and after aging are as follows (film thickness is 10.0±0.5μm) as shown in Table 1 and Table 2.

[0182] Table 1. Performance and rate of change of biodegradable membranes obtained in the examples and comparative examples before and after aging.

[0183]

[0184] Table 2. Performance and rate of change of biodegradable membranes obtained in the examples and comparative examples before and after aging.

[0185]

[0186] As can be seen from Tables 1 and 2, compared with Comparative Example 1 and Comparative Example 3, Comparative Example 3 replaced epoxidized Eucommia ulmoides gum with epoxidized natural rubber, which resulted in a decrease in the barrier properties and mechanical properties of the biodegradable membrane; compared with Comparative Example 1 and Comparative Example 4, replacing epoxidized Eucommia ulmoides gum with natural rubber resulted in a significant decrease in the barrier properties and mechanical properties of the biodegradable membrane.

[0187] The decrease in mechanical properties (tensile and tear strength) before and after aging reflects the beginning of degradation of the biodegradable membrane. A greater rate of change in mechanical properties before and after aging indicates faster degradation, and vice versa. Specifically, comparing Example 1, Example 5, and Comparative Example 5, Example 1 used epoxidized Eucommia ulmoides gum, Example 5 used natural Eucommia ulmoides gum, and Comparative Example 5 used an organic UV stabilizer, benzotriazole. The rate of change in mechanical properties of the biodegradable membrane obtained in Example 1 before and after aging was less than that in Example 5, indicating that the epoxidized Eucommia ulmoides gum in Example 1 is more stable and less prone to pyrolysis than natural Eucommia ulmoides gum. Conversely, the rate of change in mechanical properties of the biodegradable membrane in Comparative Example 5 was much greater than that in Examples 1 and 5, indicating that the biodegradable membrane obtained with the organic UV stabilizer benzotriazole is easily degraded and unstable. In summary, this invention uses Eucommia ulmoides gum as an additive to improve the problem of premature degradation of biodegradable membranes.

[0188] Figure 1 This is an image of the biodegradable membrane obtained in Comparative Example 1 before aging; Figure 2 Images of the biodegradable membrane obtained in Example 1 after aging; Figure 3 The image shows the biodegradable membrane obtained in Comparative Example 1 after aging. Figures 1-3 It can be seen that the PBAT degradation membrane with added epoxidized Eucommia ulmoides gum has an intact appearance and significantly better anti-aging performance than the PBAT degradation membrane without added epoxidized Eucommia ulmoides gum (the membrane surface has already shown significant cracking). Membrane aging and degradation begin from membrane cracking.

[0189] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A biodegradable membrane, characterized in that, The raw materials, prepared in 100 parts by weight, include the following components in parts by weight: 74~99.998 parts by weight of biodegradable polyester; 5-15 parts by weight of Eucommia ulmoides gum; Compatibilizer 0.1~2 parts by weight; Opening agent: 0.001~2 parts by weight; 0.1 to 2 parts by weight of coupling agent; Dispersant 0.1~2 parts by weight; 0-8 parts by weight of color masterbatch; The biodegradable polyester is poly(butylene adipate / terephthalate); The Eucommia gum is epoxidized Eucommia gum; The preparation method of the epoxidized Eucommia ulmoides gum includes the following steps: Eucommia gum, peracetic acid, an acidic catalyst, and a nonpolar solvent are mixed and epoxy-modified to obtain the epoxidized eucommia gum. The acidic catalyst is concentrated sulfuric acid; The mass ratio of Eucommia ulmoides gum, peracetic acid, and acidic catalyst is 10~25:1~10:1~5; The epoxy modification is performed at a temperature of 40-60℃ for 5-10 hours.

2. The biodegradable membrane according to claim 1, characterized in that, The compatibilizer is a non-reactive compatibilizer or a reactive compatibilizer; the non-reactive compatibilizer includes one or a mixture of several of ethylene acrylate, ethylene-ethyl acrylate and ethylene-vinyl acetate copolymer; the reactive compatibilizer includes one or a mixture of several of acid anhydride compatibilizers, epoxy compatibilizers, imine compatibilizers, carboxylic acid compatibilizers, oxazoline compatibilizers and isocyanate compatibilizers.

3. The biodegradable membrane according to claim 1, characterized in that, The opening agent is an organic opening agent and / or an inorganic opening agent; the organic opening agent includes one or a mixture of several of fatty acid amides, fatty acid esters, bis-stearamides, alkanes and siloxanes; the inorganic opening agent includes one or a mixture of several of talc, diatomaceous earth and silica. The coupling agent is a silane coupling agent, which includes one or a mixture of several of KH550, KH560, KH570 and KH590. The dispersant includes one or a mixture of stearic acid, oleic acid and titanate; The color masterbatch does not contain polyolefins or other non-biodegradable polymers.

4. The method for preparing the biodegradable membrane according to any one of claims 1 to 3, characterized in that, Includes the following steps: Biodegradable polyester, eucommia gum, compatibilizer, opening agent, coupling agent, dispersant and color masterbatch are mixed and then extruded, granulated and blown into a film to obtain the biodegradable film.

5. The method for preparing the biodegradable membrane according to any one of claims 1 to 3, characterized in that, Includes the following steps: Biodegradable polyester and eucommia gum are mixed and then extruded and granulated sequentially to obtain masterbatch. The masterbatch is mixed with compatibilizer, opening agent, coupling agent, dispersant and color masterbatch, and blown into a film to obtain the biodegradable film.

6. The method for preparing the biodegradable membrane according to any one of claims 1 to 3, characterized in that, Includes the following steps: A portion of biodegradable polyester and eucommia gum are mixed and then extruded and granulated sequentially to obtain masterbatch. The masterbatch is mixed with the remaining biodegradable polyester, compatibilizer, opening agent, coupling agent, dispersant, and color masterbatch, and then blow-molded into a film to obtain the biodegradable film.

7. The application of the biodegradable membrane according to any one of claims 1 to 3 or the biodegradable membrane prepared by the preparation method according to any one of claims 4 to 6 in agricultural mulch film, vegetable greenhouse film, injection molded sheet, injection molded sheet, shopping bag, garbage bag and food packaging.

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