Layered structure chemical fabric and preparation method thereof
By enhancing the interfacial bonding of layered chemical fiber fabrics through a multi-component synergistic system, the problems of interlayer delamination and slippage were solved, achieving durability and performance stability in harsh environments and extending the service life of the material.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-05
- Publication Date
- 2026-03-27
AI Technical Summary
Existing layered chemical fiber fabrics suffer from insufficient interfacial bonding between functional layers under harsh environments such as high and low temperature alternation and humid heat corrosion. This leads to easy peeling, slippage or cracking between layers, which seriously affects the overall performance and service life of the material.
A multi-component synergistic system is adopted, and an intermediate functional bonding layer is formed through melt blending and extrusion casting. A specially formulated nano-silica dispersion and polyisocyanate curing agent are used in the surface treatment layer, combined with γ-aminopropyltriethoxysilane and stearic acid-treated flake talc powder to enhance the interfacial bonding force.
In harsh environments such as high temperature and high humidity, the interlayer bonding performance decays at a low rate, and the interlayer structure of the material is well-maintained, which significantly improves the reliability and service life in dynamic application scenarios.
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Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of chemical fiber cloth, and particularly relates to a layered structure chemical fiber cloth and a preparation method thereof. BACKGROUND
[0002] The layered structure chemical fiber cloth refers to a special textile with a multi-layer composite structure formed by combining materials with different functions or characteristics and a fiber cloth base material through a specific process. Such materials have irreplaceable roles in individual protection (such as cut resistance, stab resistance, and bullet resistance), industrial reinforcement (such as conveyor belts and tarpaulin materials), high-end filtration (such as high-temperature flue gas filtration), and aerospace composite materials. The performance advantages of the layered structure chemical fiber cloth are derived from the ability to comprehensively exert the wear resistance, weather resistance, chemical corrosion resistance of the surface layer material, the adhesion, energy absorption, or barrier function of the intermediate layer, and the high strength and high modulus of the bottom fiber cloth through structural design.
[0003] Currently, the mainstream technical means for manufacturing high-performance layered structure chemical fiber cloth in the industry mainly include coating technology (such as blade coating and dip coating), lamination technology (bonding through hot melt adhesive film or adhesive), and impregnation drying technology. However, these traditional technologies have exposed a long-standing technical problem that has not been fundamentally solved when dealing with increasingly stringent application environments (such as long-term dynamic fatigue, high and low temperature alternation, wet heat corrosion, high-speed impact, etc.): the interface bonding force between the functional layers is insufficient, leading to easy peeling, slipping, or cracking between the layers, which seriously restricts the overall performance and service life of the material. Specifically, the existing technologies mainly have the following limitations: Most layered structure chemical fiber cloth technologies rely on simple physical adsorption or a small amount of general chemical adhesion. For example, common hot melt adhesive lamination or solvent-based adhesive coating may meet the standards in the initial state, but the interface bonding force will quickly decay under repeated bending, temperature difference changes, or long-term erosion of environmental media (such as water vapor and chemicals). This is because a strong and stable chemical bonding network and physical interlocking structure cannot be formed at the interface. In order to improve the bonding force, existing technologies usually add a single coupling agent (such as a silane coupling agent) or tackifying resin. However, the introduction of these additives often comes at the expense of other performance. For example, too much small molecule coupling agent may migrate to the interface to form a weak boundary layer; tackifying resin may reduce the heat resistance or mechanical strength of the intermediate layer. The existing solutions lack a composite interface regulation system that can simultaneously produce multiple, synergistic interactions with the fiber base material, functional fillers, and polymer matrix.
[0004] In addition, due to the difference in modulus and thermal expansion coefficient of each layer of material, the interlayer interface will become a stress concentration area under dynamic load or temperature change. The interlayer bonding layer of the prior art often has poor modulus matching, either too "soft" to cause interlayer creep when bearing, or too "hard" to cause stress to be unable to be effectively dissipated and thus to cause interfacial brittle cracking. At present, there is a lack of an intermediate layer design that can realize gradient modulus transition and effectively disperse and dissipate stress. In high temperature, high humidity or chemical corrosion environment, the traditional adhesive interface is easy to fail. For example, ordinary polyurethane or acrylate adhesive is easy to hydrolyze under high temperature and high humidity; most physical adhesion will be brittle at low temperature. The prior art is difficult to maintain stable and reliable interlayer bonding force in a wide temperature range and harsh environment. Therefore, the present application proposes a layered structured fiber cloth and a preparation method thereof. SUMMARY
[0005] The purpose of the present application is to solve the problem of insufficient interfacial bonding force between each functional layer of the layered structured fiber cloth in the background art, which leads to easy peeling, slipping or cracking between layers, and seriously restricts the performance and service life of the material as a whole. A layered structured fiber cloth and a preparation method thereof are proposed.
[0006] In a first aspect, the present application provides a layered structured fiber cloth, comprising: from bottom to top, a bottom fiber cloth substrate, an intermediate functional bonding layer and a surface treatment layer; the raw materials of the intermediate functional bonding layer are melt-blended, extruded and then laminated on the bottom fiber cloth substrate to form, and the intermediate functional bonding layer comprises the following raw materials by weight: thermoplastic polyurethane elastomer (TPU) 35-45 parts, with a glass transition temperature (Tg) of -35℃ to -25℃; Modified ethylene-vinyl acetate copolymer (EVA) 20-30 parts, wherein the content of vinyl acetate (VA) is 28-33 wt%, and the ethylene-vinyl acetate copolymer is modified by grafting maleic anhydride, and the grafting rate is 0.8-1.5%; the specific preparation method comprises: under the protection of inert gas, 100 parts by weight of ethylene-vinyl acetate copolymer (EVA) pellets, the content of vinyl acetate is 28-33 wt%, the melt flow index is 3-6 g / 10 min (190℃, 2.16 kg), and 120-150 parts by weight of toluene as a solvent are added to a reaction kettle, heated to 85-90℃ and stirred until the EVA is completely dissolved, then 3-5 parts by weight of maleic anhydride, 0.5-1.0 parts by weight of initiator dicumyl peroxide are added in turn, the temperature is maintained at 90-95℃ for 4-6 hours, after the reaction is completed, the reaction liquid is poured into excess acetone for precipitation, and the crude product is obtained by filtration, the crude product is washed with acetone for 3 times, and then dried in a vacuum drying oven at 60-70℃ until the weight is constant, to obtain the maleic anhydride grafted modified ethylene-vinyl acetate copolymer with a grafting rate of 0.8-1.5%; Hydrogenated styrene-butadiene-styrene block copolymer (SEBS) 10-15 parts; Polyether sulfone (PES) resin powder 8-12 parts, the melting point is 220-230℃; Surface treated inorganic filler 5-10 parts, the surface treated inorganic filler is flaky talc powder coated with γ-aminopropyl triethoxysilane and stearic acid, the particle size D50 is 3-5 μm, and the diameter-thickness ratio is greater than 20; Toughening agent 3-6 parts, the toughening agent is an acrylate polymer with core-shell structure, the core is crosslinked polybutadiene, and the shell is polymethyl methacrylate; Antioxidant 1010 0.3-0.6 parts; Antioxidant 168 0.2-0.4 parts; The raw materials of the surface treatment layer are mixed by solvent, aged, coated on the surface of the intermediate functional combination layer and solidified to form, and the raw materials include the following parts by weight: Hydroxyl-terminated fluorosilicon polymer 40-50 parts, the fluorine content is 15-22 wt%, and the viscosity is 3000-5000 mPa·s (25℃); Polyisocyanate curing agent 8-12 parts, which is a mixture of hexamethylene diisocyanate (HDI) trimer and isophorone diisocyanate (IPDI) trimer, and the mixing mass ratio is 1:1; Five to eight parts of a nano-silica dispersion, wherein the nano-silica is a vinyltrimethoxysilane-modified ethanol dispersion with a particle size of 10-20 nm and a solid content of 30%; the nano-silica dispersion is prepared by the following method: in a reactor equipped with a reflux condenser, a nano-silica hydrosol with a solid content of 30% and anhydrous ethanol are added, wherein the primary particle size of the silica in the nano-silica hydrosol is 10-20 nm, and the weight ratio of the nano-silica hydrosol to anhydrous ethanol is 1:1.5-2.5; the mixture is heated to 60-65°C with stirring; and glacial acetic acid is used to adjust the temperature. The pH of the system is adjusted to 4.0-5.0; then vinyltrimethoxysilane is slowly added dropwise over 1-2 hours, the amount of vinyltrimethoxysilane added being 15%-25% of the weight of silica in the nano silica hydrosol; after the addition is complete, the temperature is maintained at 60-65℃ and the reaction continues for 6-8 hours; after the reaction is completed, water, ethanol and byproduct methanol in the system are removed by vacuum distillation, and then anhydrous ethanol is added to adjust the solid content of the product to 30%, and then ultrasonically dispersed for 20-40 minutes to obtain the vinyltrimethoxysilane modified, uniform and stable nano silica ethanol dispersion.
[0007] 1-3 parts of fumed iron dioxide (Fe2O3), with a specific surface area of 90-110 m². 2 / g; 0.05-0.1 parts of dibutyltin dilaurate; 25-35 parts of ethyl acetate.
[0008] In this scheme, the surface-treated inorganic filler is prepared by the following method: (a) Pretreatment: Dry the flake talc powder at 105-110℃ for 2-4 hours to make its moisture content less than 0.5% to obtain dry talc powder with a particle size D50 of 3-5μm and an aspect ratio greater than 20. (b) Silane treatment: Place 100 parts by weight of dry talc powder in a high-speed mixer and preheat to 80-85°C; dissolve 1.5-2.5 parts by weight of γ-aminopropyltriethoxysilane in 95% ethanol at twice its weight and hydrolyze for 10 minutes to obtain a hydrolysate; under stirring in a high-speed mixer, slowly spray the hydrolysate into the talc powder in the form of atomization, and continue stirring and reacting at 85-90°C for 30 minutes after spraying. (c) Stearic acid compounding treatment: While keeping the material obtained in step b) at a temperature above 80°C, add 0.8-1.5 parts by weight of stearic acid and continue to stir at high speed for 20-30 minutes. (d) Post-processing: The processed material is dried at 90-100℃ for 1-2 hours, and then passed through a 400-mesh sieve to obtain the flake talc powder coated with γ-aminopropyltriethoxysilane and stearic acid. In this scheme, the nano-silica dispersion is prepared by the following method: In a reactor equipped with a reflux condenser, 100 parts by weight of nano silica hydrosol with a solid content of 30% (silica primary particle size 10-20nm) and 200 parts by weight of anhydrous ethanol are added, and the mixture is heated to 60-65°C with stirring. Adjust the pH of the system to 4.0-5.0 using glacial acetic acid; Then, slowly add 5-8 parts by weight of vinyltrimethoxysilane over 1 hour. After the addition is complete, maintain the temperature at 60-65°C and continue the reaction for 6-8 hours. After the reaction was completed, water, ethanol and methanol by-product were removed from the system by vacuum distillation. Finally, the solid content of the product was adjusted to 30% with anhydrous ethanol and ultrasonically dispersed for 30 minutes to obtain the vinyltrimethoxysilane modified nano silica ethanol dispersion with a particle size of 10-20 nm.
[0009] Optionally, the underlying fiber fabric substrate has a basis weight of 150-300 g / m². 2 The woven fabric has fibers selected from at least one of para-aramid fiber, ultra-high molecular weight polyethylene fiber, and polyphenylene sulfide fiber, and the fiber surface is treated with low-temperature plasma with a treatment power of 300-500W and a treatment time of 30-90 seconds.
[0010] Optionally, in the raw materials of the intermediate functional bonding layer, the specific surface area of the polyethersulfone (PES) resin powder is 2.5-4.0 m². 2 / g; the core-shell toughening agent has an average particle size of 150-250 nm and a shell thickness of 20-30% of the total particle diameter.
[0011] Optionally, the raw material for the intermediate functional bonding layer further includes 2-4 parts by weight of an adhesion promoter. The adhesion promoter is a compound whose molecular chain simultaneously contains a benzimidazole ring and an epoxy group, and its epoxy value is 0.05-0.10 eq / 100g. The specific preparation method of the adhesion promoter includes: under nitrogen protection, adding 100g of 2-(4-aminophenyl)benzimidazole and 500mL of [unclear text - possibly a typo, should be "to a four-necked flask equipped with a stirrer, condenser, and thermometer"]. N,N-Dimethylformamide (DMF) was dissolved by stirring and heated to 80°C. An excess mixture of epichlorohydrin (e.g., 200g) and 0.5g tetrabutylammonium bromide (phase transfer catalyst) was slowly added dropwise over approximately 1 hour. After the addition was complete, the temperature was raised to 100°C and the reaction was carried out for 8 hours. The reaction system was then cooled to 60°C, and 200mL of an aqueous solution containing 20g sodium hydroxide was slowly added with stirring. The reaction was continued for 4 hours to achieve ring closure. After the reaction was completed, the reaction solution was poured into a large amount of ice water to precipitate the product. The precipitate was filtered and washed with deionized water until neutral. The crude product was dissolved in an appropriate amount of tetrahydrofuran (THF) and purified again by precipitation in methanol. This process was repeated twice. The final product was dried to constant weight in a vacuum drying oven at 60°C to obtain a pale yellow solid, which is the adhesion promoter.
[0012] Optionally, in the raw materials of the surface treatment layer, the hydroxyl equivalent of the hydroxyl-terminated fluorosilicone polymer is 280-350 g / eq; the crystalline form of the fumed iron dioxide (Fe2O3) is a mixture of α phase and γ phase, wherein the α phase content accounts for more than 60%.
[0013] Optionally, the raw material of the surface treatment layer may further include 1-2 parts by weight of a leveling agent, wherein the leveling agent is polyether-modified polydimethylsiloxane with a dynamic viscosity of 100-200 mPa·s (25°C).
[0014] In a second aspect, the present invention provides a method for preparing a layered structured synthetic fiber fabric as described in the first aspect, comprising the following steps: S1. Preparation of the intermediate functional bonding layer: Thermoplastic polyurethane elastomer (TPU), modified ethylene-vinyl acetate copolymer (EVA), hydrogenated styrene-butadiene-styrene block copolymer (SEBS), polyethersulfone (PES) resin powder, surface-treated inorganic filler, toughening agent, antioxidant 1010, and antioxidant 168 are mixed in a high-speed mixer at 60-80℃ for 8-12 minutes according to the specified ratio; then the mixture is fed into a twin-screw extruder for melt blending, extrusion, water cooling, and pelletizing to obtain functional masterbatch; the temperatures of zones one to six of the twin-screw extruder are set to 165℃, 175℃, 185℃, 190℃, 185℃, and 180℃ respectively, the die temperature is 175℃, and the screw speed is 200-250 rpm. The functional masterbatch is then directly cast and laminated onto the pretreated bottom fiber cloth substrate in a molten state through a single-screw casting extruder. After being compacted by pressure rollers and cooled and shaped, an intermediate with an intermediate functional bonding layer is formed. The casting temperature is 185-195℃, the lamination pressure is 0.4-0.6 MPa, and the cooling roller temperature is 15-25℃. S2. Preparation of surface treatment coating: Under light-proof and nitrogen protection, hydroxyl-terminated fluorosilicone polymer, fumed iron dioxide (Fe2O3) and half of the ethyl acetate were first added to a dispersion vessel and dispersed at high speed of 800-1200 rpm for 30 minutes; then nano silica dispersion, dibutyltin dilaurate and the remaining ethyl acetate were added, and the speed was reduced to 300-500 rpm and dispersed for 15 minutes; finally, polyisocyanate curing agent was slowly added under stirring, and stirring was continued for 20 minutes after the addition was completed to obtain a uniform coating, which was then cured in a sealed container at 25±2℃ for 2-4 hours. S3. Coating and Curing: The cured surface treatment coating is coated onto the surface of the intermediate functional bonding layer of the intermediate obtained in step S1 by microgravure coating, and the wet film thickness is controlled at 80-120μm; then the coated material is sent into a segmented heating oven for curing, and the curing conditions are: 60℃ / 3 minutes for the first segment, 90℃ / 5 minutes for the second segment, and 120℃ / 8 minutes for the third segment; after curing, the material is cooled and wound up to obtain the layered structured chemical fiber fabric.
[0015] Optionally, in step S1, the pretreatment process of the bottom fiber cloth substrate is as follows: it is passed through a chamber equipped with a low-temperature plasma generator and treated at 400W power for 60 seconds in an oxygen atmosphere, and then used for lamination within 24 hours after treatment.
[0016] Optionally, in step S2, the material temperature is controlled to not exceed 35°C throughout the dispersion process; in step S3, the anilox roller used for microgravure coating has a line count of 120-140 lines / inch.
[0017] Optionally, a micro-air circulation is maintained in the segmented heating oven in step S3, with an air velocity of 0.5-1.0 m / s.
[0018] Compared with the prior art, this application includes at least one of the following beneficial technical effects: The layered structured synthetic fiber fabric produced by this invention exhibits significantly superior bonding strength between its functional layers compared to materials using conventional adhesive systems or simplified formulations, achieving a strong and integrated bond from the fiber substrate to the surface coating. Under harsh environmental conditions such as high temperature and high humidity, the degradation of interlayer bonding performance is controlled to an extremely low level, demonstrating excellent durability and overcoming the shortcomings of traditional materials that are prone to delamination and failure after humid and hot aging.
[0019] It is worth noting that after long-term and repeated dynamic loading such as bending and stretching, the interlayer structure of the material remains intact, and the interface is not prone to peeling or slippage due to fatigue accumulation, significantly improving reliability in dynamic application scenarios. Under continuous high-temperature environments, the interlayer bonding strength of the product of this invention can still maintain a high level, effectively avoiding problems such as interface softening and decreased adhesion caused by temperature increases. Furthermore, the synergistic improvements in strength, durability, fatigue resistance, and thermal stability jointly ensure that the material has a longer service life and a more reliable performance retention rate under complex working conditions.
[0020] In summary, this invention fundamentally improves the interlayer bonding strength of layered chemical fiber fabrics through a multi-component synergistic system, and enables it to exhibit excellent durability and performance stability under harsh conditions such as damp heat aging, dynamic fatigue, and high temperature, thereby significantly extending the service life of the material. Detailed Implementation
[0021] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.
[0022] First, the preparation of the functional material of the present invention is provided, and the preparation of the functional material is described in detail below.
[0023] Preparation Example 1: Preparation of maleic anhydride-grafted EVA (EVA-g-MAH): Under nitrogen protection, 100g of EVA (Elvax® 460) granules and 150g of toluene solvent were added to a 1L reactor, heated to 90°C, and stirred until completely dissolved. Then, 4g of maleic anhydride and 0.8g of dicumyl peroxide (DCP) were added sequentially, and the reaction was maintained at 92°C for 5 hours. After the reaction was completed, the reaction solution was poured into 2L of vigorously stirred acetone to precipitate, and the crude product was obtained by filtration. The product was washed three times with fresh acetone and dried in a vacuum drying oven at 65°C for 24 hours to constant weight. The maleic anhydride grafting rate of the product was determined by titration to be 1.2%.
[0024] Preparation Example 2: Preparation of Composite Coated Flake Talc Powder: 100g of talc powder was dried in an oven at 110℃ for 3 hours. The dried talc powder was placed in a high-speed mixer and preheated to 85℃. 2.0g of KH-550 and 4g of 95% ethanol were mixed and hydrolyzed for 10 minutes. The mixture was then slowly sprayed into the high-speed stirred talc powder using an atomizing method. After spraying, stirring was continued at 88℃ for 30 minutes. While maintaining the temperature, 1.2g of stearic acid was added, and the reaction was continued with high-speed stirring for 25 minutes. Finally, the material was dried at 95℃ for 1.5 hours and passed through a 400-mesh sieve to obtain composite coated talc powder.
[0025] Preparation Example 3: Preparation of Vinyltrimethoxysilane-Modified Nano-Silica Ethanol Dispersion: In a 500 mL three-necked flask, 100 g of Ludox® HS-30 hydrosol and 200 g of anhydrous ethanol were added, stirred, and heated to 62 °C. The pH was adjusted to 4.5 with glacial acetic acid. 7 g of vinyltrimethoxysilane (A-171) was slowly added dropwise over 1 hour. After the addition was complete, the reaction was continued at 62 °C for 7 hours. After the reaction was completed, water, ethanol, and the byproduct methanol were removed by vacuum distillation at 60 °C until the system mass was constant. Finally, anhydrous ethanol was added to readjust the solid content to 30%, and the mixture was treated with an ultrasonic cell disruptor for 30 minutes to obtain a uniform and stable modified nano-silica ethanol dispersion.
[0026] Preparation Example 4: Preparation of an epoxy-functionalized oligomer containing a benzimidazole ring. The epoxy-functionalized oligomer containing a benzimidazole ring is hereinafter referred to as "Adhesion Promoter PZ". The preparation specifically includes: Under nitrogen protection, adding 100g of 2-(4-aminophenyl)benzimidazole (purity >98%) and 500mL of N,N-dimethylformamide (DMF) to a 1L four-necked flask equipped with a stirrer, condenser, and thermometer, and stirring to dissolve. The temperature is raised to 80°C, and a mixture of 200g epichlorohydrin and 0.5g tetrabutylammonium bromide is slowly added dropwise over 1 hour through a constant-pressure dropping funnel. After the addition is complete, the temperature is raised to 100°C and the reaction is carried out for 8 hours. The system is cooled to 60°C, and 200mL of an aqueous solution containing 20g sodium hydroxide is slowly added dropwise with stirring, followed by a continued reaction at 65°C for 4 hours. After the reaction was complete, the reaction solution was poured into 3 L of ice water, and a pale yellow solid precipitated under vigorous stirring. The solid was then filtered. The crude product was dissolved in tetrahydrofuran (THF) and then precipitated in methanol; this purification process was repeated twice. The final product was dried in a vacuum drying oven at 60 °C for 48 hours. GPC analysis showed that its number-average molecular weight (Mn) was 2850 g / mol; and its epoxy value was determined to be 0.075 eq / 100g according to GB / T 1677-2008.
[0027] Example 1 S1. Pretreatment of the bottom fiber cloth: The aramid cloth is treated for 60 seconds in an oxygen atmosphere and at a power of 400W by a low-temperature plasma processor. After treatment, it immediately proceeds to the next process.
[0028] S2. Preparation and lamination of intermediate functional bonding layer: The raw materials are accurately weighed according to the following parts by weight: 35 parts TPU, 20 parts EVA-g-MAH (product of preparation example 1), 10 parts SEBS, 8 parts PES powder, 5 parts composite coated talc (product of preparation example 2), 3 parts core-shell toughening agent, 2 parts adhesion promoter PZ (product of preparation example 4), 0.3 parts antioxidant 1010, and 0.2 parts antioxidant 168.
[0029] Place all the above raw materials in a high-speed mixer and mix at 70°C for 10 minutes. Feed the mixture into a twin-screw extruder, setting the temperatures of each section as follows: zone 1 165°C, zone 2 175°C, zone 3 185°C, zone 4 190°C, zone 5 185°C, zone 6 180°C; die temperature 175°C; screw speed 220 rpm. After melt blending, extrude, water cool, and pelletize to obtain functional masterbatch.
[0030] The functional masterbatch is fed into a single-screw casting extruder, and the melt flows out through a 500mm wide T-die. At a casting temperature of 185°C, it is directly hot-pressed onto a continuously running pretreated aramid fabric. The fabric is then compacted by applying a pressure of 0.4 MPa through a pair of steel rollers, and subsequently cooled and shaped by 15°C cooling rollers to obtain an intermediate with a functional bonding layer. The thickness of the intermediate layer is controlled to be approximately 0.10 mm.
[0031] S3. Surface treatment layer coating and curing: The coating is prepared according to the following parts by weight: 40 parts of hydroxyl-terminated fluorosilicone polymer, 8 parts of a mixture of HDI trimer and IPDI trimer (mass ratio 1:1), 5 parts of modified nano silica dispersion (product of preparation example 3), 1 part of fumed iron dioxide, 0.05 parts of dibutyltin dilaurate, 28 parts of ethyl acetate, and 1 part of polyether-modified polydimethylsiloxane leveling agent (BYK-333).
[0032] Under nitrogen protection and light-proof conditions, the fluorosilicone polymer, fumed iron dioxide, and half of the ethyl acetate were first added to a dispersion vessel and dispersed at 1000 rpm for 30 minutes. Then, the modified nano-silica dispersion, leveling agent, dibutyltin dilaurate, and the remaining ethyl acetate were added, and the dispersion speed was reduced to 400 rpm for 15 minutes. Finally, the mixed polyisocyanate curing agent was slowly added while stirring, and stirring continued for 20 minutes after the addition was complete to obtain a uniform coating. The coating was then cured in a sealed container at 25°C for 3 hours.
[0033] The cured coating is applied to the surface of the intermediate functional bonding layer using a 130 lines / inch microgravure roller, with a wet film thickness controlled at 80 μm. It then enters a segmented curing tunnel: the first segment at 60°C for 3 minutes, the second at 90°C for 5 minutes, and the third at 120°C for 8 minutes, with a micro-airflow of 0.8 m / s maintained within the tunnel. After complete curing, it is cooled by cooling rollers and then wound up to obtain the final product. The dry film thickness of the surface treatment layer is approximately 15 μm.
[0034] Example 2 S1. Pretreatment of the bottom fiber cloth: The aramid cloth is treated for 60 seconds in an oxygen atmosphere and at a power of 400W by a low-temperature plasma processor. After treatment, it immediately proceeds to the next process.
[0035] S2. Preparation and lamination of intermediate functional bonding layer: The raw materials are accurately weighed according to the following parts by weight: 40 parts TPU, 25 parts EVA-g-MAH (product of preparation example 1), 12 parts SEBS, 10 parts PES powder, 7 parts composite coated talc (product of preparation example 2), 4 parts core-shell toughening agent, 3 parts adhesion promoter PZ (product of preparation example 4), 0.45 parts antioxidant 1010, and 0.3 parts antioxidant 168.
[0036] Place all the above raw materials in a high-speed mixer and mix at 70°C for 10 minutes. Feed the mixture into a twin-screw extruder, setting the temperatures of each section as follows: zone 1 165°C, zone 2 175°C, zone 3 185°C, zone 4 190°C, zone 5 185°C, zone 6 180°C; die temperature 175°C; screw speed 220 rpm. After melt blending, extrude, water cool, and pelletize to obtain functional masterbatch.
[0037] The functional masterbatch is fed into a single-screw casting extruder, and the melt flows out through a 500mm wide T-die. At a casting temperature of 190°C, it is directly hot-pressed onto a continuously running pretreated aramid fabric. The fabric is then compacted by applying a pressure of 0.5 MPa through a pair of steel rollers, and subsequently cooled and shaped by 15°C cooling rollers to obtain an intermediate with a functional bonding layer. The thickness of the intermediate layer is controlled to be approximately 0.10 mm.
[0038] S3. Surface treatment layer coating and curing: The coating is prepared according to the following parts by weight: 45 parts of hydroxyl-terminated fluorosilicone polymer, 8 parts of a mixture of HDI trimer and IPDI trimer (mass ratio 1:1), 6 parts of modified nano silica dispersion (product of preparation example 3), 2 parts of fumed iron dioxide, 0.07 parts of dibutyltin dilaurate, 30 parts of ethyl acetate, and 1.5 parts of polyether-modified polydimethylsiloxane leveling agent (BYK-333).
[0039] Under nitrogen protection and light-proof conditions, the fluorosilicone polymer, fumed iron dioxide, and half of the ethyl acetate were first added to a dispersion vessel and dispersed at 1000 rpm for 30 minutes. Then, the modified nano-silica dispersion, leveling agent, dibutyltin dilaurate, and the remaining ethyl acetate were added, and the dispersion speed was reduced to 400 rpm for 15 minutes. Finally, the mixed polyisocyanate curing agent was slowly added while stirring, and stirring continued for 20 minutes after the addition was complete to obtain a uniform coating. The coating was then cured in a sealed container at 25°C for 3 hours.
[0040] The cured coating is applied to the surface of the intermediate functional bonding layer using a 130 lines / inch microgravure roller, with a wet film thickness controlled at 100 μm. It then enters a segmented curing tunnel: the first segment at 60°C for 3 minutes, the second at 90°C for 5 minutes, and the third at 120°C for 8 minutes, with a micro-airflow of 0.8 m / s maintained within the tunnel. After complete curing, it is cooled by cooling rollers and then wound up to obtain the final product. The dry film thickness of the surface treatment layer is approximately 15 μm.
[0041] Example 3 S1. Pretreatment of the bottom fiber cloth: The aramid cloth is treated for 60 seconds in an oxygen atmosphere and at a power of 400W by a low-temperature plasma processor. After treatment, it immediately proceeds to the next process.
[0042] S2. Preparation and lamination of intermediate functional bonding layer: The raw materials are accurately weighed according to the following parts by weight: 45 parts TPU, 30 parts EVA-g-MAH (product of preparation example 1), 15 parts SEBS, 12 parts PES powder, 10 parts composite coated talc (product of preparation example 2), 6 parts core-shell toughening agent, 4 parts adhesion promoter PZ (product of preparation example 4), 0.6 parts antioxidant 1010, and 0.4 parts antioxidant 168.
[0043] Place all the above raw materials in a high-speed mixer and mix at 70°C for 10 minutes. Feed the mixture into a twin-screw extruder, setting the temperatures of each section as follows: zone 1 165°C, zone 2 175°C, zone 3 185°C, zone 4 190°C, zone 5 185°C, zone 6 180°C; die temperature 175°C; screw speed 220 rpm. After melt blending, extrude, water cool, and pelletize to obtain functional masterbatch.
[0044] The functional masterbatch is fed into a single-screw casting extruder, and the melt flows out through a 500mm wide T-die. At a casting temperature of 195°C, it is directly hot-pressed onto a continuously running pretreated aramid fabric. The fabric is then compacted by applying a pressure of 0.6 MPa through a pair of steel rollers, and subsequently cooled and shaped by 15°C cooling rollers to obtain an intermediate with a functional bonding layer. The thickness of the intermediate layer is controlled to be approximately 0.10 mm.
[0045] S3. Surface treatment layer coating and curing: The coating is prepared according to the following parts by weight: 50 parts of hydroxyl-terminated fluorosilicone polymer, 12 parts of a mixture of HDI trimer and IPDI trimer (mass ratio 1:1), 8 parts of modified nano silica dispersion (product of preparation example 3), 3 parts of fumed iron dioxide, 0.1 parts of dibutyltin dilaurate, 35 parts of ethyl acetate, and 2 parts of polyether modified polydimethylsiloxane leveling agent (BYK-333).
[0046] Under nitrogen protection and light-proof conditions, the fluorosilicone polymer, fumed iron dioxide, and half of the ethyl acetate were first added to a dispersion vessel and dispersed at 1000 rpm for 30 minutes. Then, the modified nano-silica dispersion, leveling agent, dibutyltin dilaurate, and the remaining ethyl acetate were added, and the dispersion speed was reduced to 400 rpm for 15 minutes. Finally, the mixed polyisocyanate curing agent was slowly added while stirring, and stirring continued for 20 minutes after the addition was complete to obtain a uniform coating. The coating was then cured in a sealed container at 25°C for 3 hours.
[0047] The cured coating is applied to the surface of the intermediate functional bonding layer using a 130 lines / inch microgravure roller, with a wet film thickness controlled at 120 μm. It then enters a segmented curing tunnel: the first segment at 60°C for 3 minutes, the second at 90°C for 5 minutes, and the third at 120°C for 8 minutes, with a micro-airflow of 0.8 m / s maintained within the tunnel. After complete curing, it is cooled by cooling rollers and then wound up to obtain the final product. The dry film thickness of the surface treatment layer is approximately 15 μm.
[0048] Comparative Example 1: Except for replacing 3 parts of adhesion promoter PZ in the intermediate functional bonding layer of Example 2 with an equal amount of conventional epoxy silane coupling agent KH-560, the other raw materials, proportions and preparation steps are exactly the same as in Example 2.
[0049] Comparative Example 2: Except that no fumed iron dioxide was added to the surface treatment coating of Example 2, and the total mass of the coating remained unchanged (i.e., the missing 2 parts were made up by ethyl acetate), the other raw materials, proportions and preparation steps were exactly the same as those of Example 2.
[0050] Comparative Example 3: Except for the following modifications to the intermediate functional bonding layer of Example 2, the other preparation steps were the same: no composite coated talc powder was used, and an equal amount of untreated raw talc powder of the same specification was used instead; no PES powder was added; no adhesion promoter PZ was added. The intermediate layer raw materials were changed to: 40 parts TPU, 25 parts EVA-g-MAH, 12 parts SEBS, 7 parts raw talc, 4 parts core-shell toughening agent, 0.45 parts antioxidant 1010, and 0.3 parts antioxidant 168.
[0051] Performance Testing and Results Analysis The products obtained in Examples 1-3 and Comparative Examples 1-3 were subjected to the following performance tests, and the results are summarized in Table 1.
[0052] Initial interlayer peel strength: Refer to GB / T 2790-1995, use a universal testing machine, perform a 180° peel test at a speed of 100 mm / min, unit N / cm.
[0053] Peel strength retention rate after damp heat aging: After aging the sample in a constant temperature and humidity chamber at 85°C and 85% relative humidity for 168 hours (7 days), remove it and cool it to room temperature, then test its peel strength. Calculate the retention rate (strength after aging / initial strength × 100%).
[0054] Peel strength after dynamic fatigue: The sample was subjected to 100,000 bidirectional bends (135° angle) under a tension of 1 kg on the MIT flexural strength tester, and its peel strength was tested.
[0055] High-temperature peel strength: After preheating the sample and test fixture in a 150°C oven for 30 minutes, the peel strength was quickly tested at 150°C to examine the bonding performance at high temperature.
[0056] Table 1: Performance Test Results of Layered Structured Chemical Fiber Fabric
[0057] Results Summary and Analysis: The superiority and wide-ranging effectiveness of the present invention: The initial peel strength of Examples 1-3 was significantly higher than that of the comparative examples, especially after harsh damp heat aging, dynamic fatigue and high temperature tests, the strength retention rate was extremely high (>91%). This proves that the formulation design of the present invention can effectively solve the core technical problem of easy attenuation of interlayer bonding in harsh environments throughout the entire scope of the claims.
[0058] Comparing Example 2 and Comparative Example 1: Comparative Example 1 used conventional KH-560, and while the initial strength was acceptable (67.4 N / cm), the strength decreased sharply after damp heat aging (retention rate of only 74.5%), and its performance after dynamic fatigue was also poor. In contrast, Example 2 used a specially formulated epoxy oligomer adhesion promoter PZ containing a benzimidazole ring, achieving unexpectedly significant improvements in both initial strength (86.2 N / cm) and environmental resistance (retention rate of 92.6%). This confirms that the strong polar interaction (hydrogen bonding, coordination) between the benzimidazole ring in the adhesion promoter PZ molecule and the aramid fiber, as well as the anti-migration properties brought about by its high molecular weight, synergistically produce a reaction activity with the epoxy group, achieving a long-lasting and stable chemical and physical bond.
[0059] By comparing Example 2 and Comparative Example 2: Comparative Example 2, which does not contain fumed Fe2O3, showed no significant decrease in initial and post-hygrothermal strength, but its high-temperature (150°C) peel strength (25.1 N / cm) was significantly weaker, far lower than that of Example 2 (40.5 N / cm). This indicates that nano-Fe2O3 not only shields against ultraviolet light, but its high specific surface area and surface properties also significantly enhance the interfacial interaction between the surface treatment layer and the intermediate layer (especially the exposed PES and fillers) at high temperatures during curing, acting as an "interfacial anchoring point" and improving the thermal stability of the entire composite material system.
[0060] By comparing Example 2 and Comparative Example 3: Comparative Example 3 used a simplified formulation, and all performance indicators collapsed completely, with extremely low initial strength and complete failure after humid heat. This demonstrates the multiple synergies of the intermediate layer design of the present invention: the composite-coated talc ensures excellent dispersion and stress transfer in the matrix; the combination of PES powder, as a high-melting-point rigid particle, and flake talc significantly improves modulus and creep resistance; and the adhesion promoter PZ tightly chemically bonds the fibers, fillers, and polymers.
[0061] It is worth noting that this invention constructs a composite interface system with strong chemical bonding, stable physical interlocking, and effective stress transfer through multi-component and multi-scale synergistic design, thereby fundamentally overcoming the problem of interface failure of traditional layered materials under dynamic or harsh environments. Specifically, the benzimidazole ring of the special adhesion promoter (adhesion promoter PZ) forms a strong polar interaction and coordination bond with the amide structure of the aramid fiber, while the epoxy group at its end reacts chemically with the intermediate layer polymer (the end group of TPU and the anhydride of EVA-g-MAH) at the processing temperature to form a covalent bridge. At the same time, PES powder, as a high-melting-point rigid dispersed phase, constructs a rigid-flexible reinforcing network in the matrix with high aspect ratio talc powder coated with silane and stearic acid. The talc flakes provide two-dimensional reinforcement and slip surfaces, while the PES particles play a fixing role. The good compatibility of this network with the polymer matrix ensures the effective dispersion of stress at the interface. On the surface, gaseous Fe2O3, with its high specific surface area and surface activity, generates a strong interfacial interaction with the fluorosilicone polymer and modified nano-silica during the curing process, firmly fixing the surface coating on the intermediate layer. The cross-linked network formed by the fluorosilicone polymer and the HDI / IPDI mixed trimer provides an inert protective barrier.
[0062] Furthermore, this invention achieves a significant improvement in peel strength over a wide temperature range (from low temperature to 150°C), particularly at high temperatures where the bonding strength is exceptionally stable due to the anchoring effect of Fe2O3 and the support of the PES / talc network. Secondly, the system exhibits excellent environmental tolerance, with a peel strength retention rate exceeding 91% after humid heat aging. This is attributed to the high molecular weight of the adhesion promoter PZ, its anti-migration properties, the stability of its chemical bonds, and the barrier effect of the fluorosilicone coating, which collectively prevent water molecule erosion of the interface. The dynamic fatigue performance of the material is significantly improved. The modulus gradient formed by the PES / talc network and the flexible polymer matrix effectively reduces stress concentration. Simultaneously, the adhesion promoter PZ and the composite coating ensure that the filler-matrix interface does not debond under repeated deformation, allowing the material to maintain over 90% interlayer bonding strength after 100,000 bending cycles. These effects are interconnected and mutually reinforcing, which cannot be achieved by a single component or simple combination.
[0063] The above specific embodiments are merely several optional embodiments of the present invention. Based on the technical solutions of the present invention and the relevant teachings of the above embodiments, those skilled in the art can make various alternative improvements and combinations to the above specific embodiments.
Claims
1. A layered structured synthetic fiber fabric, characterized in that, include: The structure, from bottom to top, comprises a bottom fiber fabric substrate, an intermediate functional bonding layer, and a surface treatment layer. The raw material for the intermediate functional bonding layer is formed by melt blending, extrusion casting, and then laminating it onto the bottom fiber fabric substrate. The intermediate functional bonding layer comprises the following raw materials in parts by weight: 35-45 parts of thermoplastic polyurethane elastomer; 20-30 parts of modified ethylene-vinyl acetate copolymer, wherein the vinyl acetate content is 28-33 wt%, and the ethylene-vinyl acetate copolymer is modified by maleic anhydride grafting with a grafting rate of 0.8-1.5%; 10-15 parts of hydrogenated styrene-butadiene-styrene block copolymer; 8-12 parts of polyethersulfone resin powder; 5-10 parts of surface-treated inorganic filler, wherein the surface-treated inorganic filler is flake talc powder coated with γ-aminopropyltriethoxysilane and stearic acid; Toughening agent 3-6 parts; antioxidant 1010 0.3-0.6 parts; antioxidant 168 0.2-0.4 parts; The raw materials for the surface treatment layer are mixed with solvent, aged, coated onto the surface of the intermediate functional bonding layer, and cured to form the layer, comprising the following parts by weight of raw materials: 40-50 parts of hydroxyl-terminated fluorosilicone polymer; 8-12 parts of polyisocyanate curing agent, which is a mixture of hexamethylene diisocyanate trimer and isophorone diisocyanate trimer, with a mixing mass ratio of 1:1; 5-8 parts of nano-silica dispersion, wherein the nano-silica is modified with vinyltrimethoxysilane; 1-3 parts of fumed iron dioxide; 0.05-0.1 parts of dibutyltin dilaurate; 25-35 parts of ethyl acetate.
2. The layered structured chemical fiber fabric according to claim 1, characterized in that, The underlying fiber cloth substrate has a weight of 150-300 g / m². 2 The woven fabric has fibers selected from at least one of para-aramid fiber, ultra-high molecular weight polyethylene fiber, and polyphenylene sulfide fiber, and the fiber surface is treated with low-temperature plasma with a treatment power of 300-500W and a treatment time of 30-90 seconds.
3. The layered structured chemical fiber fabric according to claim 1, characterized in that, In the raw materials of the intermediate functional bonding layer, the specific surface area of the polyethersulfone resin powder is 2.5-4.0 m². 2 / g; The toughening agent is a core-shell structured acrylate polymer, with a core of cross-linked polybutadiene and a shell of polymethyl methacrylate.
4. The layered structured chemical fiber fabric according to claim 1, characterized in that, The raw material for the intermediate functional bonding layer also includes 2-4 parts by weight of an adhesion promoter, wherein the adhesion promoter is a compound containing both a benzimidazole ring and an epoxy group on its molecular chain, and has an epoxy value of 0.05-0.10 eq / 100g.
5. The layered structured chemical fiber fabric according to claim 1, characterized in that, In the raw materials of the surface treatment layer, the fluorine content of the hydroxyl-terminated fluorosilicone polymer is 15-22 wt%, and the hydroxyl equivalent of the hydroxyl-terminated fluorosilicone polymer is 280-350 g / eq; the specific surface area of the fumed iron dioxide is 90-110 m². 2 / g, the crystalline form of fumed iron dioxide is a mixture of α phase and γ phase, of which the α phase content accounts for more than 60%.
6. The layered structured chemical fiber fabric according to claim 1, characterized in that, The raw materials for the surface treatment layer also include 1-2 parts by weight of a leveling agent, wherein the leveling agent is polyether-modified polydimethylsiloxane.
7. A method for preparing a layered structured synthetic fiber fabric as described in any one of claims 1-6, characterized in that, Includes the following steps: S1. Preparation of the intermediate functional bonding layer: Thermoplastic polyurethane elastomer, modified ethylene-vinyl acetate copolymer, hydrogenated styrene-butadiene-styrene block copolymer, polyethersulfone resin powder, surface-treated inorganic filler, toughening agent, antioxidant 1010, and antioxidant 168 are mixed in a high-speed mixer at 60-80℃ for 8-12 minutes according to the specified ratio. The mixture is then fed into a twin-screw extruder for melt blending, extrusion, water cooling, and pelletizing to obtain the functional masterbatch. The temperatures of zones one through six of the twin-screw extruder are set to 165℃, 175℃, 185℃, 190℃, 185℃, and 180℃, respectively; the die temperature is 175℃; and the screw speed is 200-250 rpm. The functional masterbatch is then directly cast and laminated onto the pretreated bottom fiber cloth substrate in a molten state through a single-screw casting extruder. After being compacted by pressure rollers and cooled and shaped, an intermediate with an intermediate functional bonding layer is formed. The casting temperature is 185-195℃, the lamination pressure is 0.4-0.6 MPa, and the cooling roller temperature is 15-25℃. S2. Preparation of surface treatment coating: Under light-proof and nitrogen protection, first, add hydroxyl-terminated fluorosilicone polymer, fumed iron dioxide and half of the amount of ethyl acetate into a dispersion vessel, and disperse at high speed of 800-1200 rpm for 30 minutes; then add nano silica dispersion, dibutyltin dilaurate and the remaining ethyl acetate, and disperse at 300-500 rpm for 15 minutes; finally, slowly add polyisocyanate curing agent while stirring, and continue stirring for 20 minutes after the addition is complete to obtain a uniform coating, and then cure in a sealed container at 25±2℃ for 2-4 hours; S3. Coating and Curing: The cured surface treatment coating is coated onto the surface of the intermediate functional bonding layer of the intermediate obtained in step S1 by microgravure coating, and the wet film thickness is controlled at 80-120μm; then the coated material is sent into a segmented heating oven for curing, and the curing conditions are: 60℃ / 3 minutes for the first segment, 90℃ / 5 minutes for the second segment, and 120℃ / 8 minutes for the third segment; after curing, the material is cooled and wound up to obtain the layered structured chemical fiber fabric.
8. The method for preparing a layered structured chemical fiber fabric according to claim 7, characterized in that, In step S1, the pretreatment process of the bottom fiber cloth substrate is as follows: it is passed through a chamber equipped with a low-temperature plasma generator and treated at 400W power for 60 seconds in an oxygen atmosphere, and then used for lamination within 24 hours after treatment.
9. The method for preparing a layered structured chemical fiber fabric according to claim 7, characterized in that, In step S2, the material temperature is controlled to not exceed 35°C throughout the dispersion process; in step S3, the anilox roller used for microgravure coating has a line count of 120-140 lines / inch.
10. The method for preparing a layered structured chemical fiber fabric according to claim 7, characterized in that, In step S3, a small airflow is maintained in the segmented heating oven, with an air velocity of 0.5-1.0 m / s.