Non-woven fabric for food-grade packaging and preparation method thereof

Abstract

The present disclosure provides a non-woven fabric, which includes 20% to 50% by weight of one or more plant-based fibers, 30% to 50% by weight of one or more low-melting point thermoplastic fibers or thermoplastic bicomponent fibers with a melting point below 180°C, and 10% to 30% by weight of one or more water-based binders. The non-woven fabric uses low-melting point thermoplastic fibers or thermoplastic bicomponent fibers, which ensures a low heat-sealing temperature while maintaining heat-sealing strength. The low binder content addresses the adhesion issue during the processing of non-woven fabric and reduces production energy consumption. By optimizing the ratio of each component, various key properties are balanced. In addition to excellent heat-sealing properties, the non-woven fabric also exhibits good processing properties, mechanical properties, and hydrophilic properties. The fabric surface is free of adhesion and has excellent technical effects in dry and wet stiffness, hygroscopicity, and roughness.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims the benefit of Chinese Patent Application No. 202410993317.3, filed with the China National Intellectual Property Administration on July 23, 2024, and entitled "NON-WOVEN FABRIC FOR FOOD-GRADE PACKAGING AND PREPARATION METHOD THEREOF", which is incorporated herein by reference in its entirety.TECHNICAL FIELD

[0002] The present disclosure relates to the technical field of non-woven fabrics, and in particular to a non-woven fabric for food-grade packaging and a preparation method thereof.BACKGROUND

[0003] Non-woven fabrics are commonly used in the manufacture of bags for holding single-serve products. The market for this type of oral pouch products has expanded to cover so-called "modern oral" products, which can be used for packaging a wide variety of materials such as non-tobacco nicotine, flavorings, tea, coffee, traditional Chinese medicine, and / or other food-grade products.

[0004] Non-woven fabrics for food packaging should possess the following characteristics: good food contact properties (food-grade), heat-sealing properties (heat-sealing temperature and heat-sealing strength), mechanical properties (transverse and longitudinal mechanical properties), support for fast processing performance (stiffness, elasticity), hydrophilicity (moisture absorption and softness), porosity, and gas permeability (release rate). The core requirement is to achieve an excellent balance of these key properties.

[0005] Currently, the leading international manufacturers of non-woven fabrics for packaging are Nonwoven from the UK and KANISHK from India, which are referred to as British fabric and Indian fabric, respectively.

[0006] Currently, British fabric is a top-tier product in the industry and the preferred choice for high-end product packaging. It is expensive and has long delivery times. However, in terms of key properties, there are several disadvantages: ① The main raw materials are 100% viscose fibers or 100% lyocell fibers and binders. Since neither viscose fiber nor lyocell fiber has good hot-melt properties, a high content of binder (30%-50%) needs to be added to achieve good heat-sealing properties. During the fiber web forming process, the fibers are bonded by immersing them in a binder, which requires adding a large amount of binder in the production of non-woven fabrics. ② The extensive use of binders makes the finished product sticky and hard to pull apart during use, and the binders can stick to the cutting blade, forming black block-like sticky stains over time, which is a pain point in the current usage process. (3) The reliance on binders for heat sealing results in unstable heat sealing performance. The higher the amount of binder used, the higher the unit energy consumption required for drying during processing, making it less environmentally friendly in terms of carbon emissions.

[0007] The product disclosed in patent application CN20228001078.9 is relatively similar to the mainstream British fabric currently in commercial circulation, with a target grammage of 25 to 40 gsm. The core formulation consists of short fibers and binders, where the short fibers are 100% lyocell fibers with a preferred fineness of 0.9-2.2 dtex. The binder content accounts for 30%-50% of the dry weight, and the binders mainly include PLA, acrylates, PBS, vinyl acetate copolymers, and vinyl acrylic copolymers, among others. The binders are applied to the fiber network mainly through impregnation and spraying, followed by drying and reinforcement to form the final product. However, the product described in this patent application has several limitations. The choice of fibers is relatively single, and the high binder content can lead to fabric adhesion, which hinders quick packaging processes. Additionally, about 100 meters near the roll core is unusable due to adhesion, causing over 10% wastage. The high binder content also results in low production yields and high energy consumption. Furthermore, the binders are mainly thermoplastic polymers, making it challenging to produce food-grade eco-friendly aqueous solutions, which poses quality and safety risks. Lastly, the core heat-sealing performance is provided by the binders in the nonwoven material, leading to insufficient heat-sealing strength and unstable heat-sealing performance.

[0008] Indian fabric is currently used mainly in low-end products and and has several major disadvantages: ① poor mechanical properties, with transverse and longitudinal strength and hand feel similar to that of paper; ② uneven fabric surface, poor control of fiber distribution; (3) poor fiber strength and heat-sealing properties; ④ poor appearance with yellowing fabric surfaces and poor quality control; ⑤ poor compatibility, poor resistance to oil and acidic substances like mint, making it unsuitable for use in wet oral tobacco products; and ⑥ long delivery time.

[0009] In view of the above issues in the prior art, the present disclosure provides a non-woven fabric for food-grade packaging that balances heat-sealing performance and processing performance, and its preparation method.SUMMARY OF THE INVENTION

[0010] The purpose of the present disclosure is to overcome the problems existing in the prior art and provide a non-woven fabric for food-grade packaging that balances heat-sealing performance and processing performance, and its preparation method. The non-woven fabric according to the present disclosure uses low-melting point thermoplastic fibers or thermoplastic bicomponent fibers, which ensure a low heat-sealing temperature and sufficient heat-sealing strength. The low content of binder resolves adhesion issues during the processing of non-woven fabric while reducing energy consumption.

[0011] In a first aspect, the present disclosure provides a non-woven fabric comprising: 20% to 50% by weight of one or more plant-based fibers; 30% to 50% by weight of one or more low-melting point thermoplastic fibers or thermoplastic bicomponent fibers with a melting point below 180°C; and 10% to 30% by weight of one or more water-based binders.

[0012] Each raw material in the non-woven fabrics according to the present disclosure is preferably food-grade. The plant-based fibers mainly provide hydrophilic and wetting properties, aiding in the rigidity during processing, making it easy to chew and giving a good mouthfeel. The low-melting point thermoplastic fibers or thermoplastic bicomponent fibers provide heat-sealing performance and an even fabric surface. The binders primarily serve to form and reinforce the web, are easy to foam, hydrophilic, and dry quickly, with a small portion contributing to the heat-sealing performance.

[0013] In an embodiment, the non-woven fabric comprises: 25% to 45% by weight of one or more plant-based fibers; 35% to 45% by weight of one or more low-melting point thermoplastic fibers or thermoplastic bicomponent fibers with a melting point below 180°C; and 15% to 25% by weight of one or more water-based binders.

[0014] In an embodiment, the content of the plant-based fiber is preferably 30% to 40% by weight, more preferably 32% to 35% by weight. The content of the low-melting point thermoplastic fiber or thermoplastic bicomponent fiber is preferably 38% to 42% by weight, more preferably 40% by weight. The content of the water-based binder is preferably 18% to 25% by weight, more preferably 20% to 25% by weight.

[0015] In an embodiment, the non-woven fabric further includes other thermoplastic fiber(s).

[0016] In an embodiment, the non-woven fabric consists of one or more plant-based fibers, one or more low-melting point thermoplastic fibers or thermoplastic bicomponent fibers with a melting point below 180°C, other thermoplastic fiber(s), and one or more water-based binders, with the total content of all components being 100% by weight.

[0017] In an embodiment, the non-woven fabric consists of one or more plant-based fibers, one or more low-melting point thermoplastic fibers or thermoplastic bicomponent fibers with a melting point below 180°C, and one or more water-based binders, with a total content of all components being 100% by weight. Preferably, the non-woven fabric consists of 35% by weight of one or more plant-based fibers, 40% by weight of one or more low-melting point thermoplastic fibers or thermoplastic bicomponent fibers with a melting point below 180°C, and 25% by weight of one or more water-based binders.

[0018] In an embodiment, the low-melting point thermoplastic fiber or thermoplastic bicomponent fiber has a melting point below 165°C, preferably below 150°C.

[0019] In an embodiment, the low-melting point thermoplastic fiber or thermoplastic bicomponent fiber may be selected from a group consisting of PE, PP, PLA, LPET, PE / PET, LPET / PET, PE / PP, PE / PLA, etc., preferably from a group consisting of PE / PET and LPET / PET. The fiber has a fineness ranging from 0.8 to 7 dtex and a length ranging from 6 to 51 mm.

[0020] In an embodiment, the plant-based fiber is selected from a group consisting of natural plant-based fibers or regenerated plant-based fibers. Preferably, the plant-based fiber is selected from a group consisting of viscose fibers, lyocell fibers, bamboo fibers, hemp fibers, wood fibers, cotton fibers, etc. More preferably, the plant-based fiber is selected from a group consisting of viscose fibers, bamboo fibers, and hemp fibers. The plant-based fiber has a fineness ranging from 1 to 6 dtex, preferably from 1.2 to 3 dtex, and a length ranging from 12 to 51 mm.

[0021] In an embodiment, the water-based binder is selected from a group consisting of vinyl acetate-ethylene copolymers, acrylates, polyurethanes, polylactic acid (PLA), polybutylene succinate (PBS), polyhydroxyalkanoates (PHA), vinyl acetate copolymers, vinyl acrylic copolymers, styrene-butadiene copolymers, etc. Preferably, the water-based binder is selected from a group consisting of vinyl acetate-ethylene copolymers and acrylates.

[0022] In an embodiment, the other thermoplastic fiber(s) is selected from a group consisting of polyester fibers, TPU fibers, PHA fibers, PA fibers, PBT fibers, etc. The fiber has a fineness ranging from 0.8 to 7 dtex and a length ranging from 6 to 51 mm.

[0023] In an embodiment, the plant-based fiber is selected from one or more of viscose fibers, bamboo fibers, and hemp fibers. The low-melting point thermoplastic fiber or thermoplastic bicomponent fiber is selected from one or both of PE / PET and LPET / PET. The water-based binder is selected from one or both of vinyl acetate-ethylene copolymers and acrylates.

[0024] In a second aspect, the present disclosure provides a bagged product, which includes a bag formed from the non-woven fabric according to the present disclosure and a product in the bag. Preferably, the product in the bag is food or traditional Chinese medicine, etc.

[0025] In a third aspect, the present disclosure provides a method for preparing the non-woven fabric according to the present disclosure. According to the composition requirements of the non-woven fabric, the following steps are performed sequentially: fiber bale unpacking, opening, metering and mixing of fibers, pre-carding, cross lapping, primary carding, longitudinal lapping, web edge trimming, foaming, foam binder application, drying and optionally including final winding and slitting steps. Preferably, a defect inspection step is also included between drying and winding.

[0026] In an embodiment, the drying is selected from a group consisting of steam drying, electric heating drying, etc.

[0027] In the method for preparing the non-woven fabric described in the present disclosure, during the fiber bale unpacking and opening stages, multiple fibers are synchronously mixed according to formulation requirements. In the carding stages, pre-carding and primary carding ensure more uniform fiber distribution, resulting in more stable longitudinal and transverse properties of the non-woven fabric. During the foam binder application stage, using foam binder technology, a small amount of binder is sufficient to bind the fibers into a web, with foam points uniformly dispersed throughout the fiber web. This results in a final non-woven fabric product with uniform porosity, better breathability, and more consistent release of substances. In the drying stage, the low binder content allows for rapid drying, low energy consumption, and high production efficiency. The defect inspection is carried out using online visual inspection, ensuring full product inspection and enhancing quality safety and reliability.

[0028] Compared with the prior art, the beneficial effects of the invention are as follows: 1. The nonwoven fabric according to the present disclosure uses low melting point thermoplastic fibers or thermoplastic bicomponent fibers and low content water-based binders. The low binder content solves the sticking problem during nonwoven fabric processing, and the drying temperature is around 100°C, reducing energy consumption. The heat-sealing temperature is low and ensures heat-sealing strength, with the heat-sealing temperature being less than 200°C. Preferably, the heat-sealing strength can reach above 14.5N. 2. The nonwoven fabric according to the present disclosure achieves optimal balance of various key performances through the optimal ratio of components. While ensuring excellent heat-sealing performance, it also has good processing performance, mechanical performance, hydrophilicity, and other properties. The fabric surface is non-sticky, with excellent technical effects in terms of dry and wet stiffness, moisture absorption, and roughness. 3. The low binder content and drying temperature of around 100°C solve the problems of low yield and high energy consumption, making the process cleaner and easier to operate. The two-stage carding process ensures uniformity and stability of the nonwoven fabric's longitudinal and transverse properties. The foam binder spraying on the fiber web uses less binder, achieving better performance, with the foam breaking into binder points scattered on the fibers, increasing the surface area, speeding up production, and increasing yield with lower energy consumption. 4. The product variety and application are more extensive, allowing for the preparation of 20-120 gsm food-grade nonwoven fabrics, promoting more application scenarios and benefiting rapid and stable packaging production processing. DETAILED DESCRIPTION

[0029] The present disclosure will now be further described with reference to specific examples, but it is not limited to these specific examples. A person skilled in the art will recognize that the present disclosure encompasses all alternatives, modifications, and equivalents that may be included within the scope of the claims.

[0030] The abbreviations used herein are defined as follows: PE: polyethylene fiber PP: polypropylene fiber PLA: polylactic acid fiber LPET: low-melting point polyester fiber PET: polyester fiber PA: polyamide fiber PBT: polybutylene terephthalate fiber PE / PET: polyethylene / polyester skin-core bicomponent low-melting point fiber PE / PP: ES fiber PE / PLA: polyethylene / polylactic acid core-shell bicomponent low-melting point fiber LPET / PET: low-melting point polyester bicomponent fiber TPU: thermoplastic polyurethane PHA: polyhydroxyalkanoate The present disclosure provides a non-woven fabric including: 20% to 50% by weight of one or two or more plant-based fibers, 30% to 50% by weight of one or two or more low-melting point thermoplastic fibers or thermoplastic bicomponent fibers with a melting point of less than 180°C, and 10% to 30% by weight of one or two or more water-based binders. I. Preparation Method of Non-Woven Fabric

[0031] According to the composition requirements of the non-woven fabric, the following steps are performed sequentially: fiber bale unpacking, opening, metering and mixing of fibers, pre-carding, cross lapping, primary carding, longitudinal lapping, web edge trimming, foaming, foam binder application, drying, on-line defect inspection, winding, and slitting.

[0032] During the fiber bale unpacking and opening stages, multiple fibers are synchronously mixed according to the composition requirements of the nonwoven fabric. In the carding stages, the two steps of pre-carding and primary carding ensure more uniform fiber distribution, resulting in more stable longitudinal and transverse properties of the non-woven fabric. During the foam binder application stage, using foam binder technology, a small amount of binder is sufficient to bind the fibers into a web, with foam points uniformly dispersed throughout the fiber web. This results in a final non-woven fabric product with uniform porosity, better breathability, and more consistent release of substances. In the drying stage, the low binder content allows for rapid drying, low energy consumption, and high production efficiency. The defect inspection is carried out using online visual inspection, ensuring full product inspection and enhancing quality safety and reliability The drying is preferably steam drying.II. Examples

[0033] The key indicators of the nonwoven fabric are measured according to the internationally recognized standard ISO9073.1. Comparison of effects using different thermoplastic fibers

[0034] Non-woven fabrics were prepared according to the composition requirements shown in Table 1 and tested for their key indicators (using the international general standard ISO9073). Table 1 Comparison of effects using different thermoplastic fibersBroad categoryKey categoryExampl e 1 Exampl e 2 Exampl e 3 Exampl e 4 Exampl e 5 Exampl e 6 Exampl e 7 Comparati ve example 1-1Comparati ve example 1-2Comparati ve example 1-3Plant-based fiberViscose fiber35% 35% 35% 35% 35% 35% 35% 35%35%35%Thermoplast ic fiberPE / PET 40% LPET / PET 40% PE / PP 40% PP 40% LPET 40% PE / PLA 40% PLA 40% PET40%PA40%PBT40%BinderVinyl acetate-ethylene copolymers25% 25% 25% 25% 25% 25% 25% 25%25%25%Key indicatorGrammage (g / m 2< )32.1 32.1 32.2 31.8 33.3 32.2 32.7 32.832.631.5Thickness (mm)0.228 0.225 0.231 0.234 0.222 0.219 0.227 0.2160.2120.221Transverse tensile force (N / 50mm)11.8 12.1 9.8 8.9 8.5 8.6 7.2 9.49.49.7Longitudinal tensile force (N / 50mm)83.6 81.8 74.9 65.4 60.3 62.8 59.8 84.685.182.9Heat-sealing strength (N / 50mm)15.6 15.8 14.3 14.2 13.4 12.8 11.3 14.616.713.1Heat-sealing temperature (°C)180 180 170 175 180 170 170 250230240Dry stiffnessStiff Stiff Soft Soft Soft Stiff Stiff StiffStiffStiffWet stiffnessGood Good Poor Poor Poor Average Average GoodAverageGoodHygroscopici ty (%)Good Good Good Good Good Good Good GoodGoodGoodfabric surface adhesionNone None None None None None None NoneNoneNonefabric surface roughnessModerat e Moderat e Smooth Smooth Smooth Moderat e Moderat e ModerateRoughRough

[0035] It can be seen from the data in Table 1 that the use of low-melting point thermoplastic fibers or thermoplastic bicomponent fibers and a low content of binder in Examples 1-7 results in non-woven fabrics having a heat-sealing temperature of less than 200°C while ensuring heat-sealing strength. This solves the problem of fabric surface adhesion during processing and results in low energy consumption. Among Examples 1-7, Examples 1 and 2 exhibited the best heat-sealing strength, higher than 14.5 N. Examples 1 and 2 also showed superior stiffness and fabric surface roughness compared to Examples 6-7, and even more so compared to Examples 3-5.2. Comparison of effects using different plant-based fibers

[0036] Non-woven fabrics were prepared according to the composition requirements shown in Table 2 and tested for key indicators. Table 2 Comparison of effect using different plant-based fibersBroad categoryKey categoryExam ple 1: Compar ative exampl e 2-1Compar ative exampl e 2-2Compar ative exampl e 2-3Exa mple 8: Exam ple 9: Exa mple 10 Compar ative exampl e 2-4Compar ative exampl e 2-5Exa mple 11: Compar ative exampl e 2-6Compar ative exampl e 2-7Exam ple 12: Compar ative exampl e 2-8Plant-based fiberViscose fiber35% 20%50%Bamboo fiber20%25% 35% 45% 50%Lyocell20%35% 50%Hemp fiber20%35% 50%Thermop lastic fiberPE / PET40% 55%25%55%50% 40% 30% 25%55%40% 25%55%40% 25%BinderVinyl acetate-ethylene copolyme rs25% 25%25%25%25% 25% 25% 25%25%25% 25%25%25% 25%Key indicatorGramma ge (g / m 2< )32.1 32.332.531.632.1 33 32.7 32.732.231.8 3232.731.4 31.9Thicknes s (mm)0.228 0.2270.2190.2310.228 0.225 0.231 0.2290.2320.218 0.2190.2230.228 0.219Transvers e tensile force (N / 50mm )11.8 13.19.412.410.9 11.6 10.8 9.911.110.1 8.611.710.9 9.0Longitudi nal tensile force (N / 50mm )83.6 84.672.985.181.4 82.7 80.1 73.777.978.5 57.281.882.1 69.8Heat-sealing strength (N / 50mm )15.6 16.712.416.216.2 15.1 14.5 11.814.710.2 8.715.113.8 11.2Heat-sealing temperat ure (°C)180 170200170175 180 190 200175190 210170180 200Dry stiffnessStiff SoftStiffSoftSoft Stiff Stiff StiffSoftStiff StiffSoftStiff StiffWet stiffnessGood GoodGoodGoodGood Good Good GoodAverag eAver age Averag eAverag eGood GoodHygrosco picity (%)Good Averag eGoodAverag eAver age Good Good GoodPoorGood GoodPoorAvera ge Goodfabric surface adhesionNone NoneNoneNoneNone None None NoneNoneNone NoneNoneNone Nonefabric surface roughnes sMode rate SmoothRoughSmoothSmoo th Mode rate Roug h RoughSmoothRoug h RoughSmoothMode rate Rough

[0037] It can be seen from the data in Table 2 that the use of different plant-based fibers in Examples 1 and 8-12 results in non-woven fabrics having a heat-sealing temperature of less than 200°C while ensuring heat-sealing strength. This solves the problem of fabric surface adhesion during processing and results in low energy consumption. Viscose fibers and bamboo fibers result in higher heat-sealing strength, greater than 14.5 N, and better performance in stiffness, hygroscopicity, and roughness. However, if the content of low-melting point thermoplastic fibers or thermoplastic bicomponent fibers is too low, it may result in a higher heat-sealing temperature and lower heat-sealing strength.3. Comparison of effects using different plant-based fibers and low-melting point thermoplastic fibers or thermoplastic bicomponent fibers

[0038] Non-woven fabrics were prepared according to the composition requirements shown in Table 3 and tested for key indicators. Table 3 Comparison of effects using different plant-based fibers and low-melting point thermoplastic fibers or thermoplastic bicomponent fibersBroad categoryKey categoryExample 1Example 13Example 14Example 15Example 16Example 17Example 18Example 19Example 20Plant-based fiberViscose fiber35%20%15%35%35%35%35%35%Bamboo fiber15%20%20%Hemp fiber15%Thermoplastic fiberPE / PET40%40%40%40%30%30%30%30%30%PE / PP10%PP10%PLA10%PETLPET10%LPET / PET10%BinderVinyl acetate-ethylene copolymers25%25%25%25%25%25%25%25%25%Key indicatorGrammage (g / m 2< )32.132.332.731.731.932.332.531.832.2Thickness (mm)0.2280.2290.2340.2260.2220.2320.2310.2280.229Transverse tensile force (N / 50mm)11.811.511.711.611.110.910.411.211.7Longitudinal tensile force (N / 50mm)83.682.783.584.181.181.377.480.982.8Heat-sealing strength (N / 50mm)15.615.315.815.214.313.412.312.215.4Heat-sealing temperature (°C)180180180180180180180180180Dry stiffnessStiffStiffStiffStiffSoftSoftStiffSoftStiffWet stiffnessGoodGoodGoodGoodPoorAverageAverageAverageGoodHygroscopicity (%)GoodGoodGoodGoodAverageAverageGoodGoodGoodfabric surface adhesionNoneNoneNoneNoneNoneNoneNoneNoneNonefabric surface roughnessModerateModerateModerateModerateSmoothSmoothModerateRoughModerate

[0039] It can be seen from the data in Table 3 that the use of different plant-based fibers and different combinations of low-melting point thermoplastic fibers or thermoplastic bicomponent fibers in Examples 1 and 13-20 results in non-woven fabrics having a heat-sealing temperature below 200°C while ensuring heat-sealing strength. This solves the problem of fabric surface adhesion during processing and results in low energy consumption. PE / PET and LPET / PET result in higher heat-sealing strength, greater than 14.5 N, and better performance in stiffness, hygroscopicity, and roughness.4. Comparison of effects using different binders

[0040] Non-woven fabrics were prepared according to the composition requirements shown in Table 4 and tested for key indicators. Table 4 Comparison of effects using different bindersBroad categoryKey categoryExampl e 1: Exampl e 21: Examp le 22: Examp le 23 Exampl e 24 Comparati ve example 4-1Comparati ve example 4-2Comparati ve example 4-3Comparati ve example 4-4Comparati ve example 4-5Plant-based fiberViscose fiber35% 35% 50% 45% 30% 25%10%35%35%35%Thermoplas tic staple fibersPE / PET40% 40% 40% 40% 40% 40%40%30%20%20%BinderVinyl acetate-ethylene copolymers25% 10% 15% 30% 35%50%25%45%25%Polyurethane s20%Acrylates25% 10%Key specificatio nGrammage (g / m 2< )32.1 32.1 31.9 32.2 32.0 32.432.833.131.331.7Thickness (mm)0.228 0.225 0.229 0.238 0.231 0.2320.2290.2390.2420.236Transverse tensile force (N / 50mm)11.8 11.6 6.4 7.2 12.9 13.214.912.611.110.9Longitudinal tensile force (N / 50mm)83.6 79.8 48.2 53.1 81.8 71.049.772.368.566.6Heat-sealing strength (N / 50mm)15.6 15.3 14.7 15.1 16.0 16.716.217.117.321.4Heat-sealing temperature (°C)180 190 195 190 180 180180180180180Dry stiffnessStiff Stiff Stiff Stiff Stiff SoftSoftStiffStiffStiffWet stiffnessGood Average Good Good Good AveragePoorGoodAveragePoorHygroscopic ity (%)Good Good Good Good Good AveragePoorGoodGoodPoorFabric surface adhesionNone None None None None MinorSeriousMinorSeriousSeriousFabric surface roughnessModera te Modera te Smoot h Smoot h Modera te ModerateRoughRoughRoughRough

[0041] It can be seen from the data in Table 4 that the use of different contents of binders in Examples 1 and 21-24 solves the problem of fabric surface adhesion during processing. The obtained non-woven fabric has a heat-sealing temperature below 200°C and low energy consumption while ensuring heat-sealing strength. The heat-sealing strength is greater than 14.5 N, and it exhibits excellent performance in stiffness, hygroscopicity, and roughness.

[0042] From the examples of the present disclosure, it can be seen that by using plant-based fibers, low-melting point thermoplastic fibers or thermoplastic bicomponent fibers, and water-based binders, the non-woven fabric achieves a heat-sealing temperature below 200°C while ensuring heat-sealing strength, with low energy consumption and low binder content. This solves the problem of fabric surface adhesion during processing. In the preferred embodiments of the present disclosure, using specific low-melting point thermoplastic fibers or thermoplastic bicomponent fibers ensures a heat-sealing strength above 14.5 N and further enhances processability, dry and wet stiffness, hygroscopicity, roughness, etc.

[0043] Therefore, by controlling the components and their contents in the non-woven fabric, the present disclosure achieves a balance of heat-sealing performances such as heat-sealing temperature and strength, mechanical properties such as non-adhesion on the fabric surface, dry stiffness and wet stiffness, hygroscopicity, and roughness, hydrophilicity, and processability.

[0044] In the description of the specification, references to terms such as "an embodiment" and "an example", etc., mean that specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present disclosure. In the description, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Additionally, various embodiments or examples described in the description, as well as features of various embodiments or examples, may be integrated and combined by a person skilled in the art without departing from the scope of the disclosure.

[0045] The protective scope of the present disclosure is not limited to the above-described embodiments, and it is apparent that various modifications and variations can be made to the present disclosure by a person skilled in the art without departing from the scope and spirit of the present disclosure. It is intended that the present disclosure covers modifications and variations provided they fall within the scope of the appended claims and their equivalents.

Examples

Embodiment Construction

[0029]The present disclosure will now be further described with reference to specific examples, but it is not limited to these specific examples. A person skilled in the art will recognize that the present disclosure encompasses all alternatives, modifications, and equivalents that may be included within the scope of the claims.

[0030]The abbreviations used herein are defined as follows:

PE: polyethylene fiber PP: polypropylene fiber PLA: polylactic acid fiber LPET: low-melting point polyester fiber PET: polyester fiber PA: polyamide fiber PBT: polybutylene terephthalate fiber PE / PET: polyethylene / polyester skin-core bicomponent low-melting point fiber PE / PP: ES fiber PE / PLA: polyethylene / polylactic acid core-shell bicomponent low-melting point fiber LPET / PET: low-melting point polyester bicomponent fiber TPU: thermoplastic polyurethane PHA: polyhydroxyalkanoate The present disclosure provides a non-woven fabric including: 20% to 50% by weight of one or two or more plant-based fiber...

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims the benefit of Chinese Patent Application No. 202410993317.3, filed with the China National Intellectual Property Administration on July 23, 2024, and entitled "NON-WOVEN FABRIC FOR FOOD-GRADE PACKAGING AND PREPARATION METHOD THEREOF", which is incorporated herein by reference in its entirety.TECHNICAL FIELD

[0002] The present disclosure relates to the technical field of non-woven fabrics, and in particular to a non-woven fabric for food-grade packaging and a preparation method thereof.BACKGROUND

[0003] Non-woven fabrics are commonly used in the manufacture of bags for holding single-serve products. The market for this type of oral pouch products has expanded to cover so-called "modern oral" products, which can be used for packaging a wide variety of materials such as non-tobacco nicotine, flavorings, tea, coffee, traditional Chinese medicine, and / or other food-grade products.

[0004] Non-woven fabrics for food packaging should possess the following characteristics: good food contact properties (food-grade), heat-sealing properties (heat-sealing temperature and heat-sealing strength), mechanical properties (transverse and longitudinal mechanical properties), support for fast processing performance (stiffness, elasticity), hydrophilicity (moisture absorption and softness), porosity, and gas permeability (release rate). The core requirement is to achieve an excellent balance of these key properties.

[0005] Currently, the leading international manufacturers of non-woven fabrics for packaging are Nonwoven from the UK and KANISHK from India, which are referred to as British fabric and Indian fabric, respectively.

[0006] Currently, British fabric is a top-tier product in the industry and the preferred choice for high-end product packaging. It is expensive and has long delivery times. However, in terms of key properties, there are several disadvantages: ① The main raw materials are 100% viscose fibers or 100% lyocell fibers and binders. Since neither viscose fiber nor lyocell fiber has good hot-melt properties, a high content of binder (30%-50%) needs to be added to achieve good heat-sealing properties. During the fiber web forming process, the fibers are bonded by immersing them in a binder, which requires adding a large amount of binder in the production of non-woven fabrics. ② The extensive use of binders makes the finished product sticky and hard to pull apart during use, and the binders can stick to the cutting blade, forming black block-like sticky stains over time, which is a pain point in the current usage process. (3) The reliance on binders for heat sealing results in unstable heat sealing performance. The higher the amount of binder used, the higher the unit energy consumption required for drying during processing, making it less environmentally friendly in terms of carbon emissions.

[0007] The product disclosed in patent application CN20228001078.9 is relatively similar to the mainstream British fabric currently in commercial circulation, with a target grammage of 25 to 40 gsm. The core formulation consists of short fibers and binders, where the short fibers are 100% lyocell fibers with a preferred fineness of 0.9-2.2 dtex. The binder content accounts for 30%-50% of the dry weight, and the binders mainly include PLA, acrylates, PBS, vinyl acetate copolymers, and vinyl acrylic copolymers, among others. The binders are applied to the fiber network mainly through impregnation and spraying, followed by drying and reinforcement to form the final product. However, the product described in this patent application has several limitations. The choice of fibers is relatively single, and the high binder content can lead to fabric adhesion, which hinders quick packaging processes. Additionally, about 100 meters near the roll core is unusable due to adhesion, causing over 10% wastage. The high binder content also results in low production yields and high energy consumption. Furthermore, the binders are mainly thermoplastic polymers, making it challenging to produce food-grade eco-friendly aqueous solutions, which poses quality and safety risks. Lastly, the core heat-sealing performance is provided by the binders in the nonwoven material, leading to insufficient heat-sealing strength and unstable heat-sealing performance.

[0008] Indian fabric is currently used mainly in low-end products and and has several major disadvantages: ① poor mechanical properties, with transverse and longitudinal strength and hand feel similar to that of paper; ② uneven fabric surface, poor control of fiber distribution; (3) poor fiber strength and heat-sealing properties; ④ poor appearance with yellowing fabric surfaces and poor quality control; ⑤ poor compatibility, poor resistance to oil and acidic substances like mint, making it unsuitable for use in wet oral tobacco products; and ⑥ long delivery time.

[0009] In view of the above issues in the prior art, the present disclosure provides a non-woven fabric for food-grade packaging that balances heat-sealing performance and processing performance, and its preparation method.SUMMARY OF THE INVENTION

[0010] The purpose of the present disclosure is to overcome the problems existing in the prior art and provide a non-woven fabric for food-grade packaging that balances heat-sealing performance and processing performance, and its preparation method. The non-woven fabric according to the present disclosure uses low-melting point thermoplastic fibers or thermoplastic bicomponent fibers, which ensure a low heat-sealing temperature and sufficient heat-sealing strength. The low content of binder resolves adhesion issues during the processing of non-woven fabric while reducing energy consumption.

[0011] In a first aspect, the present disclosure provides a non-woven fabric comprising: 20% to 50% by weight of one or more plant-based fibers; 30% to 50% by weight of one or more low-melting point thermoplastic fibers or thermoplastic bicomponent fibers with a melting point below 180°C; and 10% to 30% by weight of one or more water-based binders.

[0012] Each raw material in the non-woven fabrics according to the present disclosure is preferably food-grade. The plant-based fibers mainly provide hydrophilic and wetting properties, aiding in the rigidity during processing, making it easy to chew and giving a good mouthfeel. The low-melting point thermoplastic fibers or thermoplastic bicomponent fibers provide heat-sealing performance and an even fabric surface. The binders primarily serve to form and reinforce the web, are easy to foam, hydrophilic, and dry quickly, with a small portion contributing to the heat-sealing performance.

[0013] In an embodiment, the non-woven fabric comprises: 25% to 45% by weight of one or more plant-based fibers; 35% to 45% by weight of one or more low-melting point thermoplastic fibers or thermoplastic bicomponent fibers with a melting point below 180°C; and 15% to 25% by weight of one or more water-based binders.

[0014] In an embodiment, the content of the plant-based fiber is preferably 30% to 40% by weight, more preferably 32% to 35% by weight. The content of the low-melting point thermoplastic fiber or thermoplastic bicomponent fiber is preferably 38% to 42% by weight, more preferably 40% by weight. The content of the water-based binder is preferably 18% to 25% by weight, more preferably 20% to 25% by weight.

[0015] In an embodiment, the non-woven fabric further includes other thermoplastic fiber(s).

[0016] In an embodiment, the non-woven fabric consists of one or more plant-based fibers, one or more low-melting point thermoplastic fibers or thermoplastic bicomponent fibers with a melting point below 180°C, other thermoplastic fiber(s), and one or more water-based binders, with the total content of all components being 100% by weight.

[0017] In an embodiment, the non-woven fabric consists of one or more plant-based fibers, one or more low-melting point thermoplastic fibers or thermoplastic bicomponent fibers with a melting point below 180°C, and one or more water-based binders, with a total content of all components being 100% by weight. Preferably, the non-woven fabric consists of 35% by weight of one or more plant-based fibers, 40% by weight of one or more low-melting point thermoplastic fibers or thermoplastic bicomponent fibers with a melting point below 180°C, and 25% by weight of one or more water-based binders.

[0018] In an embodiment, the low-melting point thermoplastic fiber or thermoplastic bicomponent fiber has a melting point below 165°C, preferably below 150°C.

[0019] In an embodiment, the low-melting point thermoplastic fiber or thermoplastic bicomponent fiber may be selected from a group consisting of PE, PP, PLA, LPET, PE / PET, LPET / PET, PE / PP, PE / PLA, etc., preferably from a group consisting of PE / PET and LPET / PET. The fiber has a fineness ranging from 0.8 to 7 dtex and a length ranging from 6 to 51 mm.

[0020] In an embodiment, the plant-based fiber is selected from a group consisting of natural plant-based fibers or regenerated plant-based fibers. Preferably, the plant-based fiber is selected from a group consisting of viscose fibers, lyocell fibers, bamboo fibers, hemp fibers, wood fibers, cotton fibers, etc. More preferably, the plant-based fiber is selected from a group consisting of viscose fibers, bamboo fibers, and hemp fibers. The plant-based fiber has a fineness ranging from 1 to 6 dtex, preferably from 1.2 to 3 dtex, and a length ranging from 12 to 51 mm.

[0021] In an embodiment, the water-based binder is selected from a group consisting of vinyl acetate-ethylene copolymers, acrylates, polyurethanes, polylactic acid (PLA), polybutylene succinate (PBS), polyhydroxyalkanoates (PHA), vinyl acetate copolymers, vinyl acrylic copolymers, styrene-butadiene copolymers, etc. Preferably, the water-based binder is selected from a group consisting of vinyl acetate-ethylene copolymers and acrylates.

[0022] In an embodiment, the other thermoplastic fiber(s) is selected from a group consisting of polyester fibers, TPU fibers, PHA fibers, PA fibers, PBT fibers, etc. The fiber has a fineness ranging from 0.8 to 7 dtex and a length ranging from 6 to 51 mm.

[0023] In an embodiment, the plant-based fiber is selected from one or more of viscose fibers, bamboo fibers, and hemp fibers. The low-melting point thermoplastic fiber or thermoplastic bicomponent fiber is selected from one or both of PE / PET and LPET / PET. The water-based binder is selected from one or both of vinyl acetate-ethylene copolymers and acrylates.

[0024] In a second aspect, the present disclosure provides a bagged product, which includes a bag formed from the non-woven fabric according to the present disclosure and a product in the bag. Preferably, the product in the bag is food or traditional Chinese medicine, etc.

[0025] In a third aspect, the present disclosure provides a method for preparing the non-woven fabric according to the present disclosure. According to the composition requirements of the non-woven fabric, the following steps are performed sequentially: fiber bale unpacking, opening, metering and mixing of fibers, pre-carding, cross lapping, primary carding, longitudinal lapping, web edge trimming, foaming, foam binder application, drying and optionally including final winding and slitting steps. Preferably, a defect inspection step is also included between drying and winding.

[0026] In an embodiment, the drying is selected from a group consisting of steam drying, electric heating drying, etc.

[0027] In the method for preparing the non-woven fabric described in the present disclosure, during the fiber bale unpacking and opening stages, multiple fibers are synchronously mixed according to formulation requirements. In the carding stages, pre-carding and primary carding ensure more uniform fiber distribution, resulting in more stable longitudinal and transverse properties of the non-woven fabric. During the foam binder application stage, using foam binder technology, a small amount of binder is sufficient to bind the fibers into a web, with foam points uniformly dispersed throughout the fiber web. This results in a final non-woven fabric product with uniform porosity, better breathability, and more consistent release of substances. In the drying stage, the low binder content allows for rapid drying, low energy consumption, and high production efficiency. The defect inspection is carried out using online visual inspection, ensuring full product inspection and enhancing quality safety and reliability.

[0028] Compared with the prior art, the beneficial effects of the invention are as follows: 1. The nonwoven fabric according to the present disclosure uses low melting point thermoplastic fibers or thermoplastic bicomponent fibers and low content water-based binders. The low binder content solves the sticking problem during nonwoven fabric processing, and the drying temperature is around 100°C, reducing energy consumption. The heat-sealing temperature is low and ensures heat-sealing strength, with the heat-sealing temperature being less than 200°C. Preferably, the heat-sealing strength can reach above 14.5N. 2. The nonwoven fabric according to the present disclosure achieves optimal balance of various key performances through the optimal ratio of components. While ensuring excellent heat-sealing performance, it also has good processing performance, mechanical performance, hydrophilicity, and other properties. The fabric surface is non-sticky, with excellent technical effects in terms of dry and wet stiffness, moisture absorption, and roughness. 3. The low binder content and drying temperature of around 100°C solve the problems of low yield and high energy consumption, making the process cleaner and easier to operate. The two-stage carding process ensures uniformity and stability of the nonwoven fabric's longitudinal and transverse properties. The foam binder spraying on the fiber web uses less binder, achieving better performance, with the foam breaking into binder points scattered on the fibers, increasing the surface area, speeding up production, and increasing yield with lower energy consumption. 4. The product variety and application are more extensive, allowing for the preparation of 20-120 gsm food-grade nonwoven fabrics, promoting more application scenarios and benefiting rapid and stable packaging production processing. DETAILED DESCRIPTION

[0029] The present disclosure will now be further described with reference to specific examples, but it is not limited to these specific examples. A person skilled in the art will recognize that the present disclosure encompasses all alternatives, modifications, and equivalents that may be included within the scope of the claims.

[0030] The abbreviations used herein are defined as follows: PE: polyethylene fiber PP: polypropylene fiber PLA: polylactic acid fiber LPET: low-melting point polyester fiber PET: polyester fiber PA: polyamide fiber PBT: polybutylene terephthalate fiber PE / PET: polyethylene / polyester skin-core bicomponent low-melting point fiber PE / PP: ES fiber PE / PLA: polyethylene / polylactic acid core-shell bicomponent low-melting point fiber LPET / PET: low-melting point polyester bicomponent fiber TPU: thermoplastic polyurethane PHA: polyhydroxyalkanoate The present disclosure provides a non-woven fabric including: 20% to 50% by weight of one or two or more plant-based fibers, 30% to 50% by weight of one or two or more low-melting point thermoplastic fibers or thermoplastic bicomponent fibers with a melting point of less than 180°C, and 10% to 30% by weight of one or two or more water-based binders. I. Preparation Method of Non-Woven Fabric

[0031] According to the composition requirements of the non-woven fabric, the following steps are performed sequentially: fiber bale unpacking, opening, metering and mixing of fibers, pre-carding, cross lapping, primary carding, longitudinal lapping, web edge trimming, foaming, foam binder application, drying, on-line defect inspection, winding, and slitting.

[0032] During the fiber bale unpacking and opening stages, multiple fibers are synchronously mixed according to the composition requirements of the nonwoven fabric. In the carding stages, the two steps of pre-carding and primary carding ensure more uniform fiber distribution, resulting in more stable longitudinal and transverse properties of the non-woven fabric. During the foam binder application stage, using foam binder technology, a small amount of binder is sufficient to bind the fibers into a web, with foam points uniformly dispersed throughout the fiber web. This results in a final non-woven fabric product with uniform porosity, better breathability, and more consistent release of substances. In the drying stage, the low binder content allows for rapid drying, low energy consumption, and high production efficiency. The defect inspection is carried out using online visual inspection, ensuring full product inspection and enhancing quality safety and reliability The drying is preferably steam drying.II. Examples

[0033] The key indicators of the nonwoven fabric are measured according to the internationally recognized standard ISO9073.1. Comparison of effects using different thermoplastic fibers

[0034] Non-woven fabrics were prepared according to the composition requirements shown in Table 1 and tested for their key indicators (using the international general standard ISO9073). Table 1 Comparison of effects using different thermoplastic fibersBroad categoryKey categoryExampl e 1 Exampl e 2 Exampl e 3 Exampl e 4 Exampl e 5 Exampl e 6 Exampl e 7 Comparati ve example 1-1Comparati ve example 1-2Comparati ve example 1-3Plant-based fiberViscose fiber35% 35% 35% 35% 35% 35% 35% 35%35%35%Thermoplast ic fiberPE / PET 40% LPET / PET 40% PE / PP 40% PP 40% LPET 40% PE / PLA 40% PLA 40% PET40%PA40%PBT40%BinderVinyl acetate-ethylene copolymers25% 25% 25% 25% 25% 25% 25% 25%25%25%Key indicatorGrammage (g / m 2< )32.1 32.1 32.2 31.8 33.3 32.2 32.7 32.832.631.5Thickness (mm)0.228 0.225 0.231 0.234 0.222 0.219 0.227 0.2160.2120.221Transverse tensile force (N / 50mm)11.8 12.1 9.8 8.9 8.5 8.6 7.2 9.49.49.7Longitudinal tensile force (N / 50mm)83.6 81.8 74.9 65.4 60.3 62.8 59.8 84.685.182.9Heat-sealing strength (N / 50mm)15.6 15.8 14.3 14.2 13.4 12.8 11.3 14.616.713.1Heat-sealing temperature (°C)180 180 170 175 180 170 170 250230240Dry stiffnessStiff Stiff Soft Soft Soft Stiff Stiff StiffStiffStiffWet stiffnessGood Good Poor Poor Poor Average Average GoodAverageGoodHygroscopici ty (%)Good Good Good Good Good Good Good GoodGoodGoodfabric surface adhesionNone None None None None None None NoneNoneNonefabric surface roughnessModerat e Moderat e Smooth Smooth Smooth Moderat e Moderat e ModerateRoughRough

[0035] It can be seen from the data in Table 1 that the use of low-melting point thermoplastic fibers or thermoplastic bicomponent fibers and a low content of binder in Examples 1-7 results in non-woven fabrics having a heat-sealing temperature of less than 200°C while ensuring heat-sealing strength. This solves the problem of fabric surface adhesion during processing and results in low energy consumption. Among Examples 1-7, Examples 1 and 2 exhibited the best heat-sealing strength, higher than 14.5 N. Examples 1 and 2 also showed superior stiffness and fabric surface roughness compared to Examples 6-7, and even more so compared to Examples 3-5.2. Comparison of effects using different plant-based fibers

[0036] Non-woven fabrics were prepared according to the composition requirements shown in Table 2 and tested for key indicators. Table 2 Comparison of effect using different plant-based fibersBroad categoryKey categoryExam ple 1: Compar ative exampl e 2-1Compar ative exampl e 2-2Compar ative exampl e 2-3Exa mple 8: Exam ple 9: Exa mple 10 Compar ative exampl e 2-4Compar ative exampl e 2-5Exa mple 11: Compar ative exampl e 2-6Compar ative exampl e 2-7Exam ple 12: Compar ative exampl e 2-8Plant-based fiberViscose fiber35% 20%50%Bamboo fiber20%25% 35% 45% 50%Lyocell20%35% 50%Hemp fiber20%35% 50%Thermop lastic fiberPE / PET40% 55%25%55%50% 40% 30% 25%55%40% 25%55%40% 25%BinderVinyl acetate-ethylene copolyme rs25% 25%25%25%25% 25% 25% 25%25%25% 25%25%25% 25%Key indicatorGramma ge (g / m 2< )32.1 32.332.531.632.1 33 32.7 32.732.231.8 3232.731.4 31.9Thicknes s (mm)0.228 0.2270.2190.2310.228 0.225 0.231 0.2290.2320.218 0.2190.2230.228 0.219Transvers e tensile force (N / 50mm )11.8 13.19.412.410.9 11.6 10.8 9.911.110.1 8.611.710.9 9.0Longitudi nal tensile force (N / 50mm )83.6 84.672.985.181.4 82.7 80.1 73.777.978.5 57.281.882.1 69.8Heat-sealing strength (N / 50mm )15.6 16.712.416.216.2 15.1 14.5 11.814.710.2 8.715.113.8 11.2Heat-sealing temperat ure (°C)180 170200170175 180 190 200175190 210170180 200Dry stiffnessStiff SoftStiffSoftSoft Stiff Stiff StiffSoftStiff StiffSoftStiff StiffWet stiffnessGood GoodGoodGoodGood Good Good GoodAverag eAver age Averag eAverag eGood GoodHygrosco picity (%)Good Averag eGoodAverag eAver age Good Good GoodPoorGood GoodPoorAvera ge Goodfabric surface adhesionNone NoneNoneNoneNone None None NoneNoneNone NoneNoneNone Nonefabric surface roughnes sMode rate SmoothRoughSmoothSmoo th Mode rate Roug h RoughSmoothRoug h RoughSmoothMode rate Rough

[0037] It can be seen from the data in Table 2 that the use of different plant-based fibers in Examples 1 and 8-12 results in non-woven fabrics having a heat-sealing temperature of less than 200°C while ensuring heat-sealing strength. This solves the problem of fabric surface adhesion during processing and results in low energy consumption. Viscose fibers and bamboo fibers result in higher heat-sealing strength, greater than 14.5 N, and better performance in stiffness, hygroscopicity, and roughness. However, if the content of low-melting point thermoplastic fibers or thermoplastic bicomponent fibers is too low, it may result in a higher heat-sealing temperature and lower heat-sealing strength.3. Comparison of effects using different plant-based fibers and low-melting point thermoplastic fibers or thermoplastic bicomponent fibers

[0038] Non-woven fabrics were prepared according to the composition requirements shown in Table 3 and tested for key indicators. Table 3 Comparison of effects using different plant-based fibers and low-melting point thermoplastic fibers or thermoplastic bicomponent fibersBroad categoryKey categoryExample 1Example 13Example 14Example 15Example 16Example 17Example 18Example 19Example 20Plant-based fiberViscose fiber35%20%15%35%35%35%35%35%Bamboo fiber15%20%20%Hemp fiber15%Thermoplastic fiberPE / PET40%40%40%40%30%30%30%30%30%PE / PP10%PP10%PLA10%PETLPET10%LPET / PET10%BinderVinyl acetate-ethylene copolymers25%25%25%25%25%25%25%25%25%Key indicatorGrammage (g / m 2< )32.132.332.731.731.932.332.531.832.2Thickness (mm)0.2280.2290.2340.2260.2220.2320.2310.2280.229Transverse tensile force (N / 50mm)11.811.511.711.611.110.910.411.211.7Longitudinal tensile force (N / 50mm)83.682.783.584.181.181.377.480.982.8Heat-sealing strength (N / 50mm)15.615.315.815.214.313.412.312.215.4Heat-sealing temperature (°C)180180180180180180180180180Dry stiffnessStiffStiffStiffStiffSoftSoftStiffSoftStiffWet stiffnessGoodGoodGoodGoodPoorAverageAverageAverageGoodHygroscopicity (%)GoodGoodGoodGoodAverageAverageGoodGoodGoodfabric surface adhesionNoneNoneNoneNoneNoneNoneNoneNoneNonefabric surface roughnessModerateModerateModerateModerateSmoothSmoothModerateRoughModerate

[0039] It can be seen from the data in Table 3 that the use of different plant-based fibers and different combinations of low-melting point thermoplastic fibers or thermoplastic bicomponent fibers in Examples 1 and 13-20 results in non-woven fabrics having a heat-sealing temperature below 200°C while ensuring heat-sealing strength. This solves the problem of fabric surface adhesion during processing and results in low energy consumption. PE / PET and LPET / PET result in higher heat-sealing strength, greater than 14.5 N, and better performance in stiffness, hygroscopicity, and roughness.4. Comparison of effects using different binders

[0040] Non-woven fabrics were prepared according to the composition requirements shown in Table 4 and tested for key indicators. Table 4 Comparison of effects using different bindersBroad categoryKey categoryExampl e 1: Exampl e 21: Examp le 22: Examp le 23 Exampl e 24 Comparati ve example 4-1Comparati ve example 4-2Comparati ve example 4-3Comparati ve example 4-4Comparati ve example 4-5Plant-based fiberViscose fiber35% 35% 50% 45% 30% 25%10%35%35%35%Thermoplas tic staple fibersPE / PET40% 40% 40% 40% 40% 40%40%30%20%20%BinderVinyl acetate-ethylene copolymers25% 10% 15% 30% 35%50%25%45%25%Polyurethane s20%Acrylates25% 10%Key specificatio nGrammage (g / m 2< )32.1 32.1 31.9 32.2 32.0 32.432.833.131.331.7Thickness (mm)0.228 0.225 0.229 0.238 0.231 0.2320.2290.2390.2420.236Transverse tensile force (N / 50mm)11.8 11.6 6.4 7.2 12.9 13.214.912.611.110.9Longitudinal tensile force (N / 50mm)83.6 79.8 48.2 53.1 81.8 71.049.772.368.566.6Heat-sealing strength (N / 50mm)15.6 15.3 14.7 15.1 16.0 16.716.217.117.321.4Heat-sealing temperature (°C)180 190 195 190 180 180180180180180Dry stiffnessStiff Stiff Stiff Stiff Stiff SoftSoftStiffStiffStiffWet stiffnessGood Average Good Good Good AveragePoorGoodAveragePoorHygroscopic ity (%)Good Good Good Good Good AveragePoorGoodGoodPoorFabric surface adhesionNone None None None None MinorSeriousMinorSeriousSeriousFabric surface roughnessModera te Modera te Smoot h Smoot h Modera te ModerateRoughRoughRoughRough

[0041] It can be seen from the data in Table 4 that the use of different contents of binders in Examples 1 and 21-24 solves the problem of fabric surface adhesion during processing. The obtained non-woven fabric has a heat-sealing temperature below 200°C and low energy consumption while ensuring heat-sealing strength. The heat-sealing strength is greater than 14.5 N, and it exhibits excellent performance in stiffness, hygroscopicity, and roughness.

[0042] From the examples of the present disclosure, it can be seen that by using plant-based fibers, low-melting point thermoplastic fibers or thermoplastic bicomponent fibers, and water-based binders, the non-woven fabric achieves a heat-sealing temperature below 200°C while ensuring heat-sealing strength, with low energy consumption and low binder content. This solves the problem of fabric surface adhesion during processing. In the preferred embodiments of the present disclosure, using specific low-melting point thermoplastic fibers or thermoplastic bicomponent fibers ensures a heat-sealing strength above 14.5 N and further enhances processability, dry and wet stiffness, hygroscopicity, roughness, etc.

[0043] Therefore, by controlling the components and their contents in the non-woven fabric, the present disclosure achieves a balance of heat-sealing performances such as heat-sealing temperature and strength, mechanical properties such as non-adhesion on the fabric surface, dry stiffness and wet stiffness, hygroscopicity, and roughness, hydrophilicity, and processability.

[0044] In the description of the specification, references to terms such as "an embodiment" and "an example", etc., mean that specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present disclosure. In the description, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Additionally, various embodiments or examples described in the description, as well as features of various embodiments or examples, may be integrated and combined by a person skilled in the art without departing from the scope of the disclosure.

[0045] The protective scope of the present disclosure is not limited to the above-described embodiments, and it is apparent that various modifications and variations can be made to the present disclosure by a person skilled in the art without departing from the scope and spirit of the present disclosure. It is intended that the present disclosure covers modifications and variations provided they fall within the scope of the appended claims and their equivalents.

Examples

Embodiment Construction

[0029]The present disclosure will now be further described with reference to specific examples, but it is not limited to these specific examples. A person skilled in the art will recognize that the present disclosure encompasses all alternatives, modifications, and equivalents that may be included within the scope of the claims.

[0030]The abbreviations used herein are defined as follows:

PE: polyethylene fiber PP: polypropylene fiber PLA: polylactic acid fiber LPET: low-melting point polyester fiber PET: polyester fiber PA: polyamide fiber PBT: polybutylene terephthalate fiber PE / PET: polyethylene / polyester skin-core bicomponent low-melting point fiber PE / PP: ES fiber PE / PLA: polyethylene / polylactic acid core-shell bicomponent low-melting point fiber LPET / PET: low-melting point polyester bicomponent fiber TPU: thermoplastic polyurethane PHA: polyhydroxyalkanoate The present disclosure provides a non-woven fabric including: 20% to 50% by weight of one or two or more plant-based fiber...

Claims

1. A non-woven fabric, characterized in that the non-woven fabric comprises: 20% to 50% by weight of one or more plant-based fibers; 30% to 50% by weight of one or more low-melting point thermoplastic fibers or thermoplastic bicomponent fibers with a melting point below 180°C; and 10% to 30% by weight of one or more water-based binders.

2. The non-woven fabric of claim 1, characterized in that the non-woven fabric comprises: 25% to 45% by weight of one or more plant-based fibers; 35% to 45% by weight of one or more low-melting point thermoplastic fibers or thermoplastic bicomponent fibers with a melting point below 180°C; and 15% to 25% by weight of one or more water-based binders.

3. The non-woven fabric of claim 1 or 2, characterized in that the non-woven fabric further comprises other thermoplastic fiber(s).

4. The non-woven fabric of claim 3, characterized in that the non-woven fabric consists of one or more plant-based fibers, one or more low-melting point thermoplastic fibers or thermoplastic bicomponent fibers with a melting point below 180°C, other thermoplastic fiber(s), and one or more water-based binders, with a total content of all components being 100% by weight.

5. The non-woven fabric of claim 1 or 2, characterized in that the non-woven fabric consists of one or more plant-based fibers, one or more low-melting point thermoplastic fibers or thermoplastic bicomponent fibers with a melting point below 180°C, and one or more water-based binders, with a total content of all components being 100% by weight; preferably, the non-woven fabric consists of 35% by weight of one or more plant-based fibers, 40% by weight of one or more low-melting point thermoplastic fibers or thermoplastic bicomponent fibers with a melting point below 180°C, and 25% by weight of one or more water-based binders.

6. The non-woven fabric of any one of claims 1-5, characterized in that the low-melting point thermoplastic fiber or thermoplastic bicomponent fiber is selected from a group consisting of PE, PP, PLA, LPET, PE / PET, LPET / PET, PE / PP, and PE / PLA, preferably from a group consisting of PE / PET, and LPET / PET.

7. The non-woven fabric of any one of claims 1-6, characterized in that the plant-based fiber is selected from a group consisting of natural plant-based fibers or regenerated plant-based fibers; preferably, the plant-based fiber is selected from a group consisting of viscose fibers, lyocell fibers, bamboo fibers, hemp fibers, wood fibers, and cotton fibers; more preferably, the plant-based fiber is selected from a group consisting of viscose fibers, bamboo fibers, and hemp fibers.

8. The non-woven fabric of any one of claims 1-7, characterized in that the water-based binder is selected from a group consisting of vinyl acetate-ethylene copolymers, acrylates, polyurethanes, polylactic acid (PLA), polybutylene succinate (PBS), polyhydroxyalkanoates (PHA), vinyl acetate copolymers, vinyl acrylic copolymers, and styrene-butadiene copolymers; preferably, the water-based binder is selected from a group consisting of vinyl acetate-ethylene copolymers and acrylates.

9. A bagged product comprising a bag formed from the non-woven fabric of any one of claims 1-8 and a product in the bag; preferably, the product in the bag is food or traditional Chinese medicine.

10. A method for preparing a non-woven fabric, characterized in that according to the composition requirements of the non-woven fabric of any one of claims 1-8, the method comprises the following steps which are performed sequentially: fiber bale unpacking, opening, metering and mixing of fibers, pre-carding, cross lapping, primary carding, longitudinal lapping, web edge trimming, foaming, foam binder application, and drying; and optionally comprising a final winding step; preferably, a defect inspection step is further included between the drying and the winding.

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