Material for woven bag as well as preparation method and application of material

Abstract

The invention discloses a material for woven bags as well as a preparation method and application thereof, and relates to the technical field of processing of materials for woven bags. The woven bag material comprises a film covering material and a weaving wire material; wherein the film covering material comprises degradable resin B and a compatilizer; the degradable resin B comprises poly (butylene adipate-co-terephthalate) and polypropylene carbonate; the woven bag material prepared from the material for weaving the silk and the material for coating is low in cost, low in rigidity and good in toughness; the mechanical strength of the coated material for the woven bag is enhanced, the water resistance is improved, the service life of the material for the woven bag is prolonged, the degradation rate of the material in the using process is delayed, and closed loop of carbon circulation is effectively achieved. The preparation method of the material for the woven bag is simple to operate; the prepared material for the woven bag or the woven bag can be widely applied to the fields of agriculture, industry and logistics transportation.

Description

Technical Field

[0001] This invention relates to the field of woven bag processing technology, and more specifically, to a material for woven bags, its preparation method, and its application. Background Technology

[0002] Woven bags, as a widely used packaging material, are involved in multiple fields such as industry, agriculture, and logistics, playing a crucial role, especially in grain transportation, fertilizer packaging, and express delivery, with a huge annual consumption. Currently, most woven bags on the market are made from polyethylene (PE) or polypropylene (PP) through processes such as melt spinning and weaving. Although these materials have advantages such as low cost, high strength, and excellent processing performance, their degradation cycle in the natural environment can be as long as hundreds of years, making them difficult for microorganisms to effectively decompose, leading to serious "white pollution" due to long-term accumulation. In particular, agricultural film residues after use in farmland and ultra-thin plastic bags (usually less than 0.025 mm thick) widely used in the express delivery industry are easily broken into microplastic particles. Once these particles enter soil and aquatic ecosystems, they not only disrupt the ecological balance but may also accumulate through the food chain, posing a potential threat to the health of animals, plants, and humans. For example, they can cause digestive tract obstruction, poisoning, or even death in marine life if ingested.

[0003] In recent years, with the promotion of environmental protection policies and the popularization of the concept of sustainable development, some studies have attempted to use biodegradable resins in the manufacture of woven bags to alleviate the environmental pollution problems caused by traditional plastics. Among them, polylactic acid (PLA), as a typical bio-based biodegradable material, has been proposed in some patents as a substitute for traditional polyolefin materials. However, the high price of PLA itself leads to a significant increase in the cost of the woven bags produced, limiting its large-scale application. In addition, PLA has a rigid molecular structure and insufficient material toughness. Without coating treatment, direct use in weaving results in brittle bags with poor impact resistance. At the same time, due to the lack of a functional protective layer, existing biodegradable woven bags generally suffer from low mechanical strength and poor water resistance. In actual use, they are prone to premature performance degradation due to environmental humidity or mechanical stress, thus affecting the normal service life and load-bearing reliability.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a material for woven bags, its preparation method, and its application, so as to solve or improve the above-mentioned technical problems.

[0006] This invention is implemented as follows: In a first aspect, embodiments of the present invention provide a material for woven bags, the material for woven bags including a coating material and a weaving yarn material; By weight, the coating material comprises the following components: 99.5-99.95 parts of degradable resin B and 0.05-0.5 parts of compatibilizer; Among them, the degradable resin B includes polybutylene terephthalate and polypropylene carbonate.

[0007] Secondly, embodiments of the present invention provide a woven bag made from the woven bag material as described above.

[0008] Thirdly, embodiments of the present invention provide a method for preparing a woven bag as described above, comprising the following steps: After mixing the woven yarns with the materials in a certain proportion, the yarns are extruded into a film and cut into filaments to make the woven bag body. After mixing the coating materials in a certain proportion, the mixture is melted to obtain the coating liquid. A coating liquid is applied to the surface of the woven bag body to produce the woven bag.

[0009] Fourthly, embodiments of the present invention provide the application of the woven bag material as described above, or the woven bag as described above, or the woven bag prepared by the preparation method as described above, in the fields of agriculture, industry, and logistics transportation.

[0010] The present invention has the following beneficial effects: The woven bag materials, their preparation methods, and applications provided in this invention embodiment utilize biodegradable PBAT as the main material and PLA and PPC as auxiliary materials for both the woven yarn material and the coating material. The woven bag materials prepared from these materials are low-cost, exhibiting low rigidity and excellent toughness. The coated woven bag materials demonstrate enhanced mechanical strength and improved water resistance, extending their service life and slowing their degradation rate during use, effectively achieving a closed-loop carbon cycle. The preparation method for the woven bag materials is simple to operate; the resulting woven bag materials or bags can be widely used in agriculture, industry, food processing, and logistics transportation. Attached Figure Description

[0011] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 It is made of biodegradable braided yarn; Figure 2 The body is a biodegradable woven bag; Figure 3Materials for coated biodegradable woven bags. Detailed Implementation

[0013] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0014] In a first aspect, embodiments of the present invention provide a material for woven bags, the material for woven bags including a coating material and a weaving yarn material; By weight, the coating material comprises the following components: 99.5-99.95 parts of degradable resin B and 0.05-0.5 parts of compatibilizer; Among them, the degradable resin B includes polybutylene terephthalate (PBAT) and polypropylene carbonate (PPC).

[0015] The materials used in woven bags, including the coating materials and the weaving yarn materials, are mainly composed of biodegradable resins. During use, through the action of light, heat, and microorganisms, they decompose into carbon dioxide, water, and other environmentally harmless small molecules within a certain period of time (several months to several years), solving the problem of long-term waste residue at the source. To a certain extent, this can offset some carbon emissions, forming a closed loop closer to the carbon cycle, and has greater carbon reduction potential than PP (polypropylene) woven bag materials that rely entirely on fossil fuels. Woven bag materials made of polypropylene (PP) are extremely difficult to degrade in the natural environment and can exist for hundreds of years; if not properly disposed of after disposal, they can create long-term "white pollution," causing serious harm to soil, water bodies, and flora and fauna.

[0016] The strength, abrasion resistance, and weather resistance of biodegradable resins are generally not as good as those of traditional PP. This means that the load-bearing capacity of biodegradable woven bag materials may be slightly worse, and their durability may be insufficient under severe friction or long-term exposure to sun and rain. This is one of the technical problems that urgently need to be solved in this field.

[0017] In an optional embodiment, the water vapor permeability of the woven bag material is <300 g / (m²). 2 • After 24 hours, the tensile strength is >30MPa, and the tensile load after UV aging is >70% of the tensile load before UV aging. These properties meet the requirements for the use of woven bags.

[0018] In an optional embodiment, the degradable resin B further includes polylactic acid; By weight percentage, degradable resin B comprises 75 wt%-97.5 wt% polybutylene terephthalate (PET), 0 wt%-5 wt% polylactic acid (PLA), and 2 wt%-20 wt% polypropylene carbonate (PPC). Preferably, by weight percentage, the degradable resin B comprises 80 wt%-95 wt% polybutylene terephthalate, 0 wt%-4 wt% polylactic acid and 5 wt%-18 wt% polypropylene carbonate.

[0019] This invention uses polybutylene terephthalate (PBAT) as the main component, combined with polylactic acid (PLA) and polypropylene carbonate (PPC) to prepare a woven bag material with low cost, low rigidity, and good toughness. The woven bag material with film coating has enhanced mechanical strength and improved water resistance, which extends the service life of the woven bag material and slows down the degradation cycle during use.

[0020] It should be noted that polylactic acid (PLA) can be added or omitted depending on the specific application. While adding PLA can increase the rigidity of the coated woven bag and provide better strength and abrasion resistance, it also reduces flexibility. Furthermore, the lifespan of woven bags with added PLA is significantly shortened during prolonged use in humid environments. If a product with greater flexibility is desired, it can be omitted.

[0021] In an optional embodiment, the melt flow index (MFR) of polybutylene terephthalate (PET) in the degradable resin B is 10-100 (190°C, 2.16 kg); the melt flow index (MFR) of polylactic acid (PLA) is 10-100 (190°C, 2.16 kg); and the melt flow index (MFR) of polypropylene carbonate (PPC) is 10-100 (190°C, 2.16 kg). Furthermore, in the degradable resin B, the melt flow index (MFR) of polybutylene terephthalate (PET) is 15-40 (190℃, 2.16kg); the melt flow index (MFR) of polylactic acid (PLA) is 15-40 (190℃, 2.16kg); and the melt flow index (MFR) of polypropylene carbonate (PPC) is 15-30 (190℃, 2.16kg).

[0022] It should be noted that the melt flow index test method is in accordance with Method A in GB / T 3682-2000, and the test conditions are D (temperature: 190℃, 2.16kg).

[0023] A high melt flow index indicates good resin flowability; a low melt flow index indicates poor resin flowability; the higher the melt flow index, the lower the corresponding average molecular weight tends to be.

[0024] Among them, degradable resins with low average molecular weight have shorter molecular chains, fewer entanglement points between chains, and relatively weaker intermolecular forces. As a result, the tensile strength, impact resistance (toughness), and hardness of the products usually decrease, and the products are more brittle and prone to cracking. They also have lower heat distortion temperatures, making them more susceptible to creep and deformation when heated. Furthermore, they are easily attacked by moisture, microorganisms, and other environmental factors, and their initial degradation rate is usually faster.

[0025] Degradable resins with high average molecular weight have long molecular chains, many entanglement points, and strong intermolecular forces, which gives the material higher tensile strength, better toughness, and impact resistance; they also have higher heat distortion temperature and better dimensional stability; the initial degradation rate may be slower, requiring more time to break the long chains into small molecular fragments that can be consumed by microorganisms, and the degradation process may be more persistent and the strength retention period may be longer.

[0026] In an optional embodiment, the compatibilizer includes at least one of epoxy compatibilizer and isocyanate compatibilizer; the function of the compatibilizer is to improve the interfacial relationship between multiple polymers that are incompatible or have poor compatibility, promote the uniform distribution of the dispersed phase, thereby improving the processing rheology and enhancing the mechanical properties of the product.

[0027] Epoxy compatibilizers have a wide range of applications, especially suitable for polyester biodegradable plastics. They have the dual functions of "compatibility" and "chain extension", which can effectively increase the molecular weight of the blend, thereby improving the melt strength and final mechanical properties. The reactivity is relatively mild, and the requirements for temperature and time control during the processing are not so strict, making the production process easier to master.

[0028] Isocyanate compatibilizers have the following characteristics: they have extremely high reactivity, can complete the reaction rapidly in a very short processing residence time, and have high compatibility efficiency; they have extremely strong chain extension and cross-linking capabilities, as well as thickening and strengthening effects.

[0029] Among them, the epoxy compatibilizer is selected from at least one of BASF Joncryl ADR-4468, ADR-4400, chain extender 6059 and glycidyl methacrylate; The isocyanate compatibilizer is selected from at least one of diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, terephthalic diisocyanate and toluene diisocyanate.

[0030] In an optional embodiment, the material for braiding yarn comprises, by weight, the following components: 80-98 parts of degradable resin A, 2-20 parts of inorganic filler, and 0.05-0.5 parts of compatibilizer; Of which, by mass percentage, degradable resin A comprises 75 wt%-95 wt% polybutylene terephthalate (PET), 1 wt%-5 wt% polylactic acid (PLA), and 3 wt%-20 wt% polypropylene carbonate (PPC). In degradable resin A, the melt flow index (MFR) of polybutylene terephthalate (PET) is 2.5-8 (190℃, 2.16kg); the melt flow index (MFR) of polylactic acid (PLA) is 2.5-8 (190℃, 2.16kg); and the melt flow index (MFR) of polypropylene carbonate (PPC) is 2-8 (190℃, 2.16kg). Preferably, in the degradable resin A, the melt flow index (MFR) of polybutylene terephthalate (PET) is 3-5 (190°C, 2.16 kg); the melt flow index (MFR) of polylactic acid (PLA) is 3-5 (190°C, 2.16 kg); and the melt flow index (MFR) of polypropylene carbonate (PPC) is 3-5 (190°C, 2.16 kg).

[0031] In an optional embodiment, the inorganic filler is selected from at least one of talc, mica, kaolinite, chlorite, halloysite, montmorillonite, and calcium carbonate.

[0032] The addition of inorganic fillers can, on the one hand, increase the rigidity and hardness of the product, improve its stability, and make the product less prone to deformation during use; on the other hand, it can help reduce cost input.

[0033] In an optional embodiment, the material for braiding yarn, by weight, further includes the following components: 0.1-1 parts plasticizer, 0.1-0.5 parts lubricant, 0.05-0.5 parts ultraviolet absorber, and 0.05-0.5 parts light stabilizer.

[0034] The plasticizer is selected from at least one of soybean oil and tri-n-butyl acetyl citrate. The plasticizer can lower the glass transition temperature, which is beneficial to increase the distance between polymer chains and weaken the intermolecular forces, thereby making the material softer and tougher, improving its flexibility and elongation, making the product softer, less brittle, and with better bending resistance.

[0035] The lubricant is selected from at least one of erucamide, oleamide, calcium stearate, stearic acid, and polyethylene wax (PE wax); it has partial compatibility with resin, can insert between polymer chains, reduce internal friction of molecular chains, reduce melt viscosity, make the melt flow more smoothly in the screw, and reduce heat accumulation; effective lubrication can prevent melt fracture, make the flat yarn surface smoother, reduce burrs, and improve gloss; in addition, it can prevent the woven fabric roll and finished bag from sticking together, which facilitates subsequent processing.

[0036] The ultraviolet absorber is selected from at least one of benzophenone-based ultraviolet absorbers and benzotriazole-based ultraviolet absorbers. The ultraviolet absorber is the first line of defense against photoaging. It converts the absorbed ultraviolet light energy into molecular vibrational energy (heat) through changes in its intramolecular structure, and restores its original structure, thus cyclically protecting the polymer molecular chain through absorption and conversion. It mainly works on the surface of the material, forming a protective layer to prevent ultraviolet rays from penetrating into the interior, and can effectively improve the tensile load of the product after ultraviolet aging.

[0037] The light stabilizer is a hindered amine light stabilizer, selected from at least one of 770, 622, and 944. It effectively inhibits free radical degradation reactions induced by ultraviolet radiation and acts as a free radical scavenger. The ultraviolet absorber absorbs some of the ultraviolet radiation, reducing the overall burden on the product; the light stabilizer removes free radicals induced by residual ultraviolet radiation. The two work synergistically to provide superior protection, offering deeper and longer-lasting protection for the product and helping to slow down its degradation rate.

[0038] Secondly, embodiments of the present invention provide a woven bag made from the woven bag material as described above.

[0039] Thirdly, embodiments of the present invention provide a method for preparing a woven bag material as described above, comprising the following steps: After mixing the woven yarns with the materials in a certain proportion, the yarns are extruded into a film and cut into filaments to make the woven bag body. After mixing the coating materials in a certain proportion, the mixture is melted to obtain the coating liquid. A coating liquid is applied to the surface of the woven bag body to produce the woven bag.

[0040] Specifically, the preparation of woven bags includes the following steps: (1) Raw material preparation (a) Preparation of materials for braiding yarn The biodegradable resin A, inorganic filler, compatibilizer, plasticizer, lubricant, UV absorber and light stabilizer are mixed in proportion and then mixed in a high-speed mixer to obtain a braided yarn mixture; The braided yarn mixture is extruded and granulated on a twin-screw extruder. The temperature in the first zone is 95℃-110℃, the second zone is 135℃-150℃, and the temperatures in the third to fifth zones are 155℃-165℃ respectively. The die temperature is 135℃-145℃. The screw speed is 300r / min-500r / min. The pelletizer speed is 150r / min-300r / min.

[0041] (b) Preparation of coating materials The degradation resin B and compatibilizer are mixed and treated in proportion to obtain the coating material; The coated material is extruded and granulated on a twin-screw extruder. The temperature in the first zone is 95℃-105℃, the second zone is 135℃-145℃, and the temperatures in the third to fifth zones are 155℃-165℃ respectively. The die temperature is 135℃-145℃. The feeding speed is 15kg / h-30kg / h, the screw speed is 250r / min-350r / min, and the pelletizer speed is 150r / min-250r / min.

[0042] (2) Preparation and weaving of braided yarn The woven yarn material prepared in step (1) (a) is placed into a high-speed drawing machine and extruded into continuous plastic filaments. The plastic filaments are then stretched to obtain biodegradable flat yarns with a thickness of 60μm-90μm. The barrel temperature is 175℃-185℃, the die temperature is 150℃-250℃, the cooling water temperature is 40℃-55℃, the traction temperature is 90℃-110℃, the traction speed is 8m / min-11m / min, the draw ratio is 62-65, and the draw ratio is 6.5-7.5. Then, the obtained flat yarns are used as warp and weft yarns respectively and woven into the woven bag body.

[0043] It should be noted that the preparation of woven bags is not particularly limited in this invention, but is only described using plain weave of warp and weft as an example; in other embodiments of this invention, twill weave, satin weave, etc., can be selected according to actual needs.

[0044] (3) Preparation of woven bags: Add the film-coating material obtained in step (1) (b) into the film-making equipment to obtain a film, and coat the film on both sides of the woven bag body; The woven bag body roll is placed at one end of the coating machine, and the coating particles are added to the coating machine to coat the woven bag body, thus obtaining a coated woven bag. The woven bag is obtained by cutting and sewing the laminated woven bag body.

[0045] Fourthly, embodiments of the present invention provide an application of the aforementioned woven bag material or the woven bag material prepared by the aforementioned method in the fields of agriculture, industry, and logistics transportation.

[0046] It should be noted that in the agricultural sector, it can be used to package fertilizers, seeds, pesticides, and agricultural products (such as rice, wheat, peanuts, corn, soybeans, and paddy rice); in the industrial sector, it can be used to package industrial materials and products; and in the logistics and transportation sector, it can be used as a logistics turnover bag to package goods.

[0047] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0048] Example 1 This embodiment provides a woven bag, the preparation of which includes the following steps: (1) Raw material preparation (a) Preparation of materials for braiding yarn The following ingredients were mixed in proportion: biodegradable resin A (15.2 kg PBAT, 0.4 kg PLA, 2 kg PPC), inorganic filler (2.4 kg layered montmorillonite), compatibilizer (40 g BASF 4468), plasticizer (100 g soybean oil), lubricant (40 g erucamide), UV absorber (UV531, 40 g), and light stabilizer (770, 20 g). The mixture was placed in a high-speed mixer (100 r / min, stirring for 5 min) and melted to obtain a woven yarn mixture. The melt flow index (MFR) of PBAT in biodegradable resin A was 3.5 (190℃, 2.16 kg), the melt flow index (MFR) of PLA was 4.0 (190℃, 2.16 kg), and the melt flow index (MFR) of PPC was 4.5 (190℃, 2.16 kg).

[0049] The braided yarn mixture is extruded and granulated on a twin-screw extruder to obtain a film; wherein the temperature of the first zone is 100℃, the temperature of the second zone is 140℃, the temperature of the third to fifth zones is 160℃, the die temperature is 140℃, the screw speed is 350r / min, and the pelletizer speed is 200r / min.

[0050] (b) Preparation of coating materials The biodegradable resin B (8 kg of PBAT, 0.4 kg of PLA, and 1.6 kg of PPC) and compatibilizer (24 g of epoxy chain extender) were mixed and melt-treated to obtain the coating material. Among them, the melt flow index (MFR) of PBAT in biodegradable resin B was 25 (190℃, 2.16 kg), the melt flow index (MFR) of PLA was 20 (190℃, 2.16 kg), and the melt flow index (MFR) of PPC was 21 (190℃, 2.16 kg).

[0051] The film coating material is extruded and granulated on a twin-screw extruder to obtain a film. The temperature of the first zone is 100℃, the second zone is 140℃, the temperature of the third to fifth zones is 160℃, the die temperature is 140℃, the feeding speed is 20kg / h, the screw speed is 300r / min, and the pelletizer speed is 200r / min.

[0052] (2) Preparation and weaving of braided yarn The woven yarn material prepared in step (1) (a) is placed into a high-speed drawing machine and extruded into continuous plastic filaments. The plastic filaments are then stretched to obtain biodegradable flat yarns with a thickness of 65 μm. The barrel temperature is 180℃, the die temperature is 200℃, the cooling water temperature is 50℃, the traction temperature is 100℃, the traction speed is 9 m / min, the draw ratio is 63.1, and the draw ratio is 7.0. Then, the obtained flat yarns are used as warp and weft yarns respectively and woven to form the woven bag body.

[0053] (3) Preparation of woven bags Add the film-coating material obtained in step (1) (b) into the coating machine. The barrel temperature is 170°C and the die head temperature is 180°C. Roll the woven bag body obtained in step (2) onto one end of the coating machine. Manually pull the woven bag body onto the other end of the winding paper tube. Start the coating machine and roll at a speed of 30m / min. Prepare the woven bag under this process. Cut and sew the coated woven bag body to obtain the woven bag.

[0054] Example 2 This embodiment provides a woven bag, the preparation steps of which are the same as those in Embodiment 1, the only difference being that: in the degradable resin A, the amount of PBAT is 14.8 kg and the amount of PLA is 0.8 kg.

[0055] Example 3 This embodiment provides a woven bag, the preparation steps of which are the same as those in Embodiment 1, the only difference being that: in the degradable resin A, the amount of PBAT is 14.2 kg and the amount of PPC is 3.0 kg.

[0056] Example 4 This embodiment provides a woven bag, the preparation steps of which are the same as those in Example 1, the only difference being that: in the degradable resin A, the amount of PBAT is 16.2 kg, the amount of PPC is 1.0 kg, and no plasticizer or light stabilizer is added.

[0057] Example 5 This embodiment provides a woven bag, the preparation steps of which are the same as those in Embodiment 1, the only difference being: degradable resin A (14.2kg PBAT, 0.4kg PLA, 1.9kg PPC) and inorganic filler (3.6kg layered montmorillonite).

[0058] Example 6 This embodiment provides a woven bag, the preparation steps of which are the same as those in Example 1, the only difference being that the melt flow index (MFR) of the PBAT of the degradable resin A is 6.1 (190°C, 2.16 kg).

[0059] Example 7 This embodiment provides a woven bag, the preparation steps of which are the same as those in Example 1, the only difference being that the melt flow index (MFR) of PPC in the degradable resin A is 7.0 (190℃, 2.16kg).

[0060] Example 8 This embodiment provides a woven bag, the preparation steps of which are the same as those in Embodiment 1, the only difference being that the inorganic filler used in the degradation resin A is flaky calcium carbonate.

[0061] Example 9 This embodiment provides a woven bag, the preparation steps of which are the same as those in Embodiment 1, the only difference being that: the PBAT in the degradable resin B is 8.4 kg and the PLA is 0 kg.

[0062] Example 10 This embodiment provides a woven bag, the preparation steps of which are the same as those in Example 1, the only difference being that: the PBAT in the degradable resin B is 7.8 kg and the PLA is 0.6 kg.

[0063] Example 11 This embodiment provides a woven bag, the preparation steps of which are the same as those in Example 1, the only difference being that: the amount of PBAT in the degradable resin B is 7.0 kg and the amount of PPC is 2.6 kg.

[0064] Example 12 This embodiment provides a woven bag, the preparation steps of which are the same as those in Example 1, the only difference being that the melt flow index (MFR) of PBAT in the degradable resin B is 3.5 (190℃, 2.16kg).

[0065] Example 13 This embodiment provides a woven bag, the preparation steps of which are the same as those in Example 1, the only difference being that the melt flow index (MFR) of PLA in the degradable resin B is 4.0 (190℃, 2.16kg).

[0066] Example 14 This embodiment provides a woven bag, the preparation steps of which are the same as those in Example 1, the only difference being that the melt flow index (MFR) of PPC in the degradable resin B is 4.5 (190℃, 2.16kg).

[0067] Example 15 This embodiment provides a woven bag, the preparation steps of which are the same as those in Example 1, the only difference being that the melt flow index (MFR) of PBAT in the degradable resin A is 25.0 (190℃, 2.16kg).

[0068] Example 16 This embodiment provides a woven bag, the preparation steps of which are the same as those in Example 1, the only difference being that the melt flow index (MFR) of PLA in the degradable resin A is 20.0 (190℃, 2.16kg).

[0069] Example 17 This embodiment provides a woven bag, the preparation steps of which are the same as those in Example 1, the only difference being that the melt flow index (MFR) of PPC in the degradable resin A is 21.0 (190℃, 2.16kg).

[0070] Comparative Example 1 This comparative example provides a woven bag whose preparation steps are the same as those in Example 1, except that no compatibilizer is added to the degradable resin B.

[0071] Comparative Example 2 This comparative example provides a woven bag, whose preparation steps are the same as those in Example 1, except that the woven bag body is not coated.

[0072] The specific steps are: missing step (1) of raw material preparation in Example 1, specifically (b) preparation of coating material; (3) Preparation of woven bags The woven bag body is cut and sewn to obtain the woven bag.

[0073] Test Example 1 This test example performs performance tests on the products prepared in Examples 1-17 and Comparative Examples 1-2. The test data are summarized in Table 1. The test items include water vapor transmission rate, tensile strength, and tensile strain before and after UV aging. The test methods are as follows: water vapor transmission rate refers to GB / T1037-2021, tensile strength, tensile strain and UV aging refer to GB / T32366-2025, and the aging rate is tensile strain after UV aging / tensile strain before UV aging × 100%.

[0074] Table 1 Performance Test Results

[0075] In summary, the woven bag materials, their preparation methods, and applications provided in this invention embodiment utilize biodegradable PBAT as the main material and PLA and PPC as auxiliary materials for both the woven yarn material and the coating material. The woven bag materials prepared from these materials are low-cost, exhibiting low rigidity and excellent toughness. The coated woven bag materials demonstrate enhanced mechanical strength and improved water resistance, extending their service life and slowing their degradation rate during use, effectively achieving a closed-loop carbon cycle. The water vapor transmission rate of the prepared woven bags is <300 g / (m²). 2After 24 hours of UV aging, the tensile strength is above 30 MPa, and the tensile load remains above 70% of its original value, meeting the requirements for woven bags. The resulting woven bag materials or woven bags can be widely used in agriculture, industry, and logistics transportation.

[0076] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A material for woven bags, characterized in that, The materials used for woven bags include coating materials and weaving yarn materials; The coating material comprises, by weight, 99.5-99.95 parts of degradable resin B and 0.05-0.5 parts of compatibilizer; The degradable resin B includes polybutylene terephthalate and polypropylene carbonate.

2. The material for woven bags according to claim 1, characterized in that, The degradable resin B also includes polylactic acid; By weight percentage, the degradable resin B comprises 75 wt%-97.5 wt% polybutylene terephthalate (PET), 0 wt%-5 wt% polylactic acid (PLA), and 2 wt%-20 wt% polypropylene carbonate (PPC). Preferably, the degradable resin B comprises, by weight percentage, 80 wt%-95 wt% polybutylene terephthalate, 0 wt%-4 wt% polylactic acid and 5 wt%-18 wt% polypropylene carbonate.

3. The material for woven bags according to claim 1, characterized in that, In the degradable resin B, the melt flow index (MFR) of polybutylene terephthalate (PET) is 10-100 (190℃, 2.16kg); the melt flow index (MFR) of polylactic acid (PLA) is 10-100 (190℃, 2.16kg); and the melt flow index (MFR) of polypropylene carbonate (PPC) is 10-100 (190℃, 2.16kg). Preferably, in the degradable resin B, the melt flow index (MFR) of polybutylene terephthalate (PET) is 15-40 (190°C, 2.16 kg); the melt flow index (MFR) of polylactic acid (PLA) is 15-40 (190°C, 2.16 kg); and the melt flow index (MFR) of polypropylene carbonate (PPC) is 15-30 (190°C, 2.16 kg).

4. The material for woven bags according to claim 1, characterized in that, The compatibilizer includes at least one of epoxy compatibilizers and isocyanate compatibilizers; The epoxy compatibilizer is selected from at least one of BASF Joncryl ADR-4468, ADR-4400, chain extender 6059 and glycidyl methacrylate; The isocyanate compatibilizer is selected from at least one of diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, terephthalic diisocyanate, and toluene diisocyanate.

5. The material for woven bags according to claim 1, characterized in that, The material for the braided yarn, by weight, comprises the following components: 80-98 parts of degradable resin A, 2-20 parts of inorganic filler, and 0.05-0.5 parts of compatibilizer; The degradable resin A, by mass percentage, comprises 75 wt%-95 wt% polybutylene terephthalate (PET), 1 wt%-5 wt% polylactic acid (PLA), and 3 wt%-20 wt% polypropylene carbonate (PPC). In the degradable resin A, the melt flow index (MFR) of polybutylene terephthalate (PET) is 2.5-8 (190℃, 2.16kg); the melt flow index (MFR) of polylactic acid (PLA) is 2.5-8 (190℃, 2.16kg); and the melt flow index (MFR) of polypropylene carbonate (PPC) is 2-8 (190℃, 2.16kg). Preferably, in the degradable resin A, the melt flow index (MFR) of polybutylene terephthalate (PET) is 3-5 (190°C, 2.16 kg); the melt flow index (MFR) of polylactic acid (PLA) is 3-5 (190°C, 2.16 kg); and the melt flow index (MFR) of polypropylene carbonate (PPC) is 3-5 (190°C, 2.16 kg). The inorganic filler is selected from at least one of talc, mica, kaolinite, chlorite, halloysite, montmorillonite, and calcium carbonate.

6. The material for woven bags according to claim 5, characterized in that, The material for the braided yarn, by weight, further includes the following components: 0.1-1 parts plasticizer, 0.1-0.5 parts lubricant, 0.05-0.5 parts ultraviolet absorber, and 0.05-0.5 parts light stabilizer; The plasticizer is selected from at least one of soybean oil and tributyl acetyl citrate; The lubricant is selected from at least one of erucamide, oleamide, calcium stearate, stearic acid, and polyethylene wax; The ultraviolet absorber is selected from at least one of benzophenone-based ultraviolet absorbers and benzotriazole-based ultraviolet absorbers; The light stabilizer is a hindered amine light stabilizer, selected from at least one of 770, 622 and 944.

7. The material for woven bags according to claim 1, characterized in that, The water vapor permeability of the material used for the woven bags is <300g / (m²). 2 • 24h), tensile strength > 30MPa, tensile load after UV aging > 70% of the tensile load before UV aging.

8. A woven bag, characterized in that, It is made from the material for woven bags as described in any one of claims 1-7.

9. A method for preparing a woven bag as described in claim 8, characterized in that, Includes the following steps: After mixing the woven yarns with materials in a certain proportion, the yarns are extruded into a film and cut into filaments to form the woven bag body. After mixing the coating materials in a certain proportion, the mixture is melted to obtain the coating liquid. The coating liquid is applied to the surface of the woven bag body to obtain a coated woven bag.

10. The application of a woven bag material as described in any one of claims 1-7, a woven bag as described in claim 8, or a woven bag prepared by the preparation method as described in claim 9 in the fields of agriculture, industry, and logistics transportation.

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