Glass fiber pre-impregnated sheet and preparation method thereof

Abstract

The invention discloses a glass fiber pre-impregnated sheet and a preparation method thereof, and relates to the technical field of phenolic glass fiber reinforced plastic plates, and the glass fiber pre-impregnated sheet is formed by impregnating non-woven glass fibers in impregnation liquid, taking out and curing; the impregnation liquid comprises the following components in percentage by mass: 15-18% of a resin material, 64-66% of a flame-retardant material, 0.5-1.5% of an auxiliary agent and the balance of water. By arranging the flame-retardant filler and the phenolic aldehyde-melamine resin system in the impregnation liquid and treating the non-woven glass fibers through the impregnation liquid, the prepared glass fiber pre-impregnated sheet has good fireproof performance and impact resistance, is suitable for being applied to the field of buildings and can be used as a fireproof plate core.

Description

Technical Field

[0001] The invention relates to the technical field of phenolic glass fiber reinforced plastic plates, in particular to a glass fiber prepreg sheet and a preparation method thereof. Background Art

[0002] With the development of social economy and the gradual improvement of people's living standards, decorative panels are widely used in building decoration and furniture manufacturing, and people's requirements for decorative materials are getting higher and higher, and the categories of decorative materials are also increasing. Fiberglass (glass fiber) decorative panels, as a kind of artificial board, can be formed by curing resin-impregnated fiberglass materials. Commonly used resin materials are thermosetting resins, and their components such as phenolic resins and melamine have good heat resistance, flame retardancy and strength properties, but they are relatively brittle, have poor impact resistance, and are prone to cracking under impact. Therefore, we propose a glass fiber prepreg sheet and a preparation method thereof. Summary of the Invention

[0003] The object of the present invention is to provide a glass fiber prepreg sheet and a preparation method thereof to solve the problems raised in the above background technology.

[0004] In order to solve the above technical problems, the present invention provides the following technical solutions: a glass fiber prepreg sheet is formed by dipping non-woven glass fibers in an impregnation liquid, taking them out, and curing them;

[0005] The impregnation liquid comprises the following components: in mass percentage, 15-18% of resin material, 64-66% of flame retardant material, 0.5-1.5% of auxiliary agent, and the balance is water.

[0006] Furthermore, the resin material is a mixture of phenolic resin and curing agent, with a mass ratio of (5-8):10.

[0007] Furthermore, the curing agent is a melamine resin curing agent.

[0008] Furthermore, the flame retardant material includes the following components: 80-90% aluminum hydroxide, 5-10% magnesium hydroxide and 5-10% silicon dioxide in percentage by mass.

[0009] Furthermore, the auxiliary agent includes the following components: in mass percentage, 30-50% of a dispersant, 20-30% of a wetting agent, 10-20% of a defoaming agent, and 20-30% of a coupling agent.

[0010] Furthermore, the mass ratio of the non-woven glass fiber to the impregnating liquid is (80-150):1000.

[0011] Furthermore, the dispersant is a polycarboxylate type dispersant;

[0012] The wetting agent is one of a nonionic surfactant and a fluorocarbon wetting agent;

[0013] The defoaming agent is one of a mineral oil defoaming agent, a polyether modified silicone, and polyvinyl acetate;

[0014] The coupling agent is one of γ-aminopropyltriethoxysilane (KH550), γ-mercaptopropyltriethoxysilane (KH590), and γ-(2,3-epoxypropoxy)propyltrimethoxysilane (KH560).

[0015] In the above technical solution, the impregnation liquid contains flame-retardant fillers such as aluminum hydroxide, magnesium hydroxide, and silicon dioxide, which form a synergistic flame-retardant effect and constitute a highly filled flame-retardant system for the impregnation liquid. The resulting glass fiber prepreg sheet has excellent flame-retardant properties and can decompose and absorb heat during combustion, releasing water vapor and diluting combustible gases to achieve the effect of suppressing combustion. It can also enhance the stability of the char layer and improve the flame retardant durability. In addition, aluminum hydroxide and magnesium hydroxide are environmentally friendly flame retardants, with no volatile components, no precipitation after long-term use, stable performance, and no halogen toxicity or corrosive gas release. Using water as a solvent can reduce VOC emissions, conforming to the trend of green manufacturing, making it suitable for application in the construction field and can be used as the core of fireproof board.

[0016] In the impregnation liquid, the phenolic resin provides high heat resistance and rigidity, and forms a dense network structure after cross-linking and curing with the melamine curing agent, thereby enhancing the mechanical strength of the glass fiber pre-impregnated sheet. Choosing a melamine curing agent can further improve its high temperature resistance and dimensional stability. The phenolic-melamine resin system has good acid, alkali and solvent resistance, making it suitable for humid or corrosive environments. The coupling agent can enhance the interfacial bonding between the glass fiber and the resin material, reduce defects, and help improve the mechanical properties of the glass fiber pre-impregnated sheet, such as tensile and bending strength. The dispersant can prevent the filler from settling and ensure the uniformity of the impregnation liquid; the wetting agent is used to reduce surface tension, which helps the impregnation liquid quickly penetrate the non-woven glass fiber; and the defoaming agent can avoid foam residue and reduce the porosity of the finished impregnated glass fiber.

[0017] A method for preparing a glass fiber prepreg sheet comprises the following processes:

[0018] Step 1. Preparation of impregnation solution:

[0019] Mixing the flame retardant filler with the coupling agent and water, and dispersing the mixture by high-speed shearing to obtain a flame retardant slurry;

[0020] mixing phenolic resin and curing agent to obtain a resin material;

[0021] Mix the resin material and flame retardant slurry, stir and disperse; add dispersant, wetting agent, coupling agent, and finally add defoaming agent, stir at low speed to obtain impregnation liquid;

[0022] Step 2. Dipping:

[0023] The non-woven glass fiber is immersed in the impregnation liquid, taken out, and solidified to obtain a glass fiber prepreg sheet.

[0024] Furthermore, in step 1, the process conditions for high-speed shear dispersion are: shearing at 1800-2000 rpm for 20-25 min, and then shearing at 1000-1200 rpm for 10-15 min;

[0025] The process conditions for stirring and dispersing are: temperature 40-50°C, rotation speed 800-1200 rpm, and duration 20-30 min;

[0026] The process conditions for low-speed stirring are: rotation speed 300-600 rpm, duration 10-20 min.

[0027] Furthermore, in step 2, the impregnation process conditions are: the impregnation liquid temperature is 25-30° C., the impregnation time is 30-90 seconds; and then the impregnation is performed with a roller pressing pressure of 0.2-0.5 MPa.

[0028] Furthermore, the resin material content of the sheet after impregnation is 5-10 wt%.

[0029] Furthermore, in step 2, during the curing process, the curing temperature is 100-150°C and the curing time is 4-10 minutes.

[0030] Furthermore, in step 2, the curing process conditions are: curing at 100-120° C. for 8-10 minutes, and then curing at 130-150° C. for 4-6 minutes.

[0031] In the above technical solution, high-speed shear dispersion ensures the full dispersion of the flame-retardant filler and coupling agent, preventing filler agglomeration. This can reduce stress concentration in the produced glass fiber prepreg, avoid local brittle fracture, and help form a continuous flame-retardant network, thereby improving flame retardancy efficiency. Medium-speed stirring and dispersion promotes compatibility between the resin system and the flame-retardant slurry. Preheating also reduces the system viscosity, making the resin more easily permeable, enhancing bonding strength, and avoiding viscosity differences during impregnation that could cause uneven composition of the produced glass fiber prepreg.

[0032] Low-temperature impregnation prevents premature curing of the resin system, ensuring it fully penetrates the glass fiber pores; short-term impregnation balances impregnation efficiency and resin absorption. Rolling squeezes out excess impregnation liquid, compacting the interface between the glass fiber and the resin, promoting resin wrapping around the glass fiber monofilaments and improving shear resistance; and balanced thickness is achieved to avoid uneven sheet thickness, which can cause uneven curing, resin enrichment, and material embrittlement.

[0033] Medium-temperature curing ensures sufficient resin curing while avoiding high-temperature decomposition and carbonization. After curing, the glass transition temperature of the resin system increases, improving the sheet's high-temperature resistance. The system also contains nitrogen, which releases a nitrogenous atmosphere during combustion, collaborating with flame-retardant fillers to suppress combustion.

[0034] Furthermore, the weight of non-woven glass fiber is 80-150g / m 2 ;

[0035] Before use, the non-woven glass fiber is preheated in an oven at 80-100°C for 1 hour to remove moisture and volatiles.

[0036] In the above technical solution, the non-woven glass fiber is preheated before use to remove the absorbed water and volatiles on the surface of the glass fiber, which can reduce moisture interference during impregnation, promote the infiltration of resin materials, alleviate the evaporation of water during curing to produce pores, and reduce product defects.

[0037] Furthermore, the non-woven glass fiber is surface modified, and the specific process is as follows:

[0038] Take non-woven glass fiber, apply coupling agent pre-hydrolyzed liquid on its surface; then dry at 80℃ to evaporate the solvent; bake at 100-120℃ to promote the reaction between silanol and glass fiber; then cool to 50-60℃ for use.

[0039] Furthermore, the concentration of the coupling agent pre-hydrolyzed solution is 1.5 to 3.0 wt%.

[0040] Furthermore, the coupling agent pre-hydrolysis solution is obtained by mixing an alcohol aqueous solution with a pH of 4 to 5 with the coupling agent and pre-hydrolyzing for 5 to 15 minutes;

[0041] The coupling agent pre-hydrolysis solution includes the following mass components: calculated by mass percentage, 1.5-3.0% coupling agent, 5-10% isopropyl alcohol, 0.05-0.10% ethylenediaminetetraacetic acid, and the balance is water;

[0042] The coupling agent was γ-(2,3-epoxypropoxy)propyltrimethoxysilane (KH560).

[0043] In the above technical solution, coupling treatment is performed to couple and modify the surface of the non-woven glass fiber, which can enhance the compatibility and interface performance between the glass fiber and the resin system, reduce brittle fracture, and improve the mechanical strength of the sheet.

[0044] Furthermore, the phenolic resin is prepared by the following process:

[0045] (1) Mixing an amino compound and deionized water, adding triethylamine, adjusting the pH of the reaction system to 8-9, and heating to 60-70°C; adding 2,4-dihydroxyacetophenone, stirring and refluxing for 20-30 minutes; cooling to room temperature after the reaction, filtering, and drying to obtain an imino compound;

[0046] The imino compound, DOPO, and p-toluenesulfonic acid are mixed in an ethanol / water mixed solution, heated to 60-80° C., reacted for 10-15 minutes, washed, and dried to obtain a nitrogen-phosphorus-containing phenol compound.

[0047] (2) Phenol, formaldehyde, nitrogen-phosphorus phenol compound, sodium hydroxide and deionized water are mixed at a temperature of 48-55°C, heated to 85-90°C, reacted for 60-90 minutes, polyvinyl alcohol is added, and the reaction is continued for 90-120 minutes; 2,4-dimethylphenol is added, and the reaction is continued at a temperature of 80-85°C for 50-90 minutes; after the reaction is completed, the mixture is cooled to 50°C, a defoaming agent is added, and the mixture is stirred at a low speed of 300 rpm for 10 minutes, and the pH of the system is adjusted to 7-8 to obtain a phenolic resin.

[0048] Furthermore, in step (1), the molar ratio of the amino group in the amino compound to the ketone group in 2,4-dihydroxyacetophenone is 1:1;

[0049] The ratio of amino compound to deionized water is (5-10) g / 100 mL;

[0050] Deionized water contains 5 wt% isopropyl alcohol as a solubilizing agent.

[0051] Furthermore, the amino compound is amino-terminated polydimethylsiloxane.

[0052] Furthermore, in step (1), the molar ratio of the imino group to the DOPO in the imino compound is 1:1;

[0053] The molar ratio of p-toluenesulfonic acid to the imino group in the imino compound is 0.5 to 1.0 mol%;

[0054] The ratio of the imino compound to the ethanol / water mixed solution is (1-3) g / 100 mL.

[0055] Furthermore, in step (2), the phenolic resin comprises the following components by mass: 16.5 to 20.7 parts of phenol, 18.2 to 23.0 parts of formaldehyde, 5 to 12 parts of nitrogen-phosphorus-containing phenol compounds, 2.6 to 4.0 parts of 2,4-dimethylphenol, 0.3 to 0.8 parts of sodium hydroxide, and 1.5 to 2.0 parts of polyvinyl alcohol;

[0056] The solid content of the phenolic resin is 65-85%.

[0057] In this technical solution, under the action of potassium hydroxide, the amino group in the amino compound reacts with the -C=O in 2,4-dihydroxyacetophenone to form -C=N-, resulting in an imino compound with a phenolic structure. This -C=N- then reacts with the -PH bond in DOPO to produce a nitrogen-phosphorus-containing phenol compound. When introduced into a phenolic resin system, the DOPO in its structure provides a rigid phenanthrene ring and phosphorus, which synergizes with nitrogen to exert a PN effect, enhancing gas-phase free radical capture and strengthening the carbon layer, thereby improving the mechanical properties, thermal stability, and flame retardancy of the resin system. The added xylenol exerts a steric hindrance effect, hindering the close packing of molecular chains and reducing brittleness.

[0058] When the amino compound is melamine, the introduction of triazine rings can further enhance the resin system's heat resistance and nitrogen content, improving its flame retardancy. When the amino compound is aminosiloxane, the resin system's flexibility can be significantly increased, effectively improving the impact resistance of the resulting sheet.

[0059] Further, the amino compound is prepared by the following process:

[0060] 2,4-bis(2-methoxy-5-allylphenyl)-6-allylphenol, amino-terminated polydimethylsiloxane, paraformaldehyde, a polymerization inhibitor and an ethanol / water mixed solution are mixed, and stirred at 85-90°C for 12-16 hours under a nitrogen atmosphere. After the reaction, water / ethanol is removed by rotary evaporation, acetone is added for dilution, extraction and washing are performed, drying is performed, rotary evaporation is repeated, washing with a NaHCO3 solution is performed, and drying is performed to obtain an amino-terminated compound.

[0061] Furthermore, the molar ratio of 2,4-bis(2-methoxy-5-allylphenyl)-6-allylphenol, amino-terminated polydimethylsiloxane, and paraformaldehyde is 1:(4.0-4.5):(1.8-2.2);

[0062] The molecular weight of amino-terminated polydimethylsiloxane is 1000 to 3500 g / mol;

[0063] The ratio of 2,4-bis(2-methoxy-5-allylphenyl)-6-allylphenol to anhydrous ethanol is (8-12) g / 100 mL;

[0064] The polymerization inhibitor is butylated hydroxytoluene (BHT), and the amount used is 0.1% of the mass of 2,4-bis(2-methoxy-5-allylphenyl)-6-allylphenol.

[0065] In the above technical solution, 2,4-bis(2-methoxy-5-allylphenyl)-6-allylphenol, amino-terminated polydimethylsiloxane, and paraformaldehyde undergo a Mannich reaction to form an amino compound with a rigid benzene ring, a benzoxazine structure, a flexible polysiloxane segment, and multifunctional reactive amino groups. The introduced benzoxazine structure undergoes ring-opening polymerization at high temperatures, forming a dense cross-linked structure containing phenolic hydroxyl groups and Mannich bridges, further improving the residual carbon content of the resin system. It also exerts a nitrogen-based flame retardant effect, decomposing at high temperatures to produce a nitrogen-containing atmosphere that dilutes combustible gases, inhibits the combustion chain reaction, and exerts a gas-phase flame retardant effect. It also promotes the formation of a char layer, which blocks the transfer of heat and combustible gases, exerting a condensed-phase flame retardant effect. It also synergizes with phosphorus and silicon flame retardants to inhibit high-temperature decomposition and improve the flame retardant properties of the resin system. The introduction of the rigid benzene ring and benzoxazine structure enhances the thermal stability and mechanical strength of the resin system.

[0066] The multifunctional active amino groups increase the crosslink density of the resin curing system, restricting molecular chain motion and enhancing the mechanical strength of the sheet. The flexible PDMS segments enhance the resin's water resistance, absorb impact energy, reduce brittle fracture, and improve the toughness and impact resistance of the resin system. The PDMS segments decompose at high temperatures to form SiO2, enhancing the stability of the carbon layer, increasing the residual carbon rate, and blocking oxygen and heat, improving the sheet's heat resistance and thermal stability. They also reduce the viscosity of the resin system, making it easier to impregnate glass fibers. The combination of flexible PDMS microdomains and a rigid crosslinked network creates a sea-island-like structure, achieving a synergistic combination of high strength and high toughness.

[0067] Furthermore, the curing agent is partially methylated melamine resin.

[0068] In the above technical solution, the curing agent has low free formaldehyde characteristics, and through the preparation of the phenolic resin and the control of the formaldehyde ratio, the generation of formaldehyde byproducts is reduced. The high crosslink density of the phenolic resin curing system can fully capture residual formaldehyde. The balanced strength and toughness of the phenolic resin curing system can alleviate the formation of microcracks and prevent formaldehyde release. The surface treatment of the glass fiber reduces the interface defects between the glass fiber and the resin bond, thus preventing formaldehyde release.

[0069] Compared with the prior art, the present invention has the following beneficial effects:

[0070] 1. The glass fiber prepreg sheet described in the present invention has good fire resistance and impact resistance through the provision of flame retardant fillers and phenolic-melamine resin system in the impregnation liquid and the treatment of non-woven glass fibers by the impregnation liquid. The glass fiber prepreg sheet is suitable for application in the construction field and can be used as the core of a fireproof board.

[0071] 2. The glass fiber prepreg sheet described in the present invention is prepared by the Mannich reaction of 2,4-bis(2-methoxy-5-allylphenyl)-6-allylphenol, amino-terminated polydimethylsiloxane, and polyformaldehyde to prepare an amino compound; then reacted with 2,4-dihydroxyacetophenone and DOPO to prepare a nitrogen-phosphorus-containing phenol compound, which is introduced into a phenolic resin curing system to achieve the introduction of branched PDMS flexible chain segments and the design of a cross-linked network structure, so that the prepared phenolic resin curing system achieves high strength and high toughness, synergistic improvement of heat resistance and flame retardancy, and excellent processing adaptability. DETAILED DESCRIPTION

[0072] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0073] In the following specific embodiments, the following is a laboratory test and can be scaled up;

[0074] The curing agent is partially methylated melamine resin Cymel 303 (Cytec Corporation);

[0075] The dispersant was polycarboxylate-type dispersant Dispex AA 4040 (BASF);

[0076] The wetting agent was fluorocarbon wetting agent Capstone FS-3100 (DuPont);

[0077] The defoamer was polyether-modified siloxane TEGO Foamex 810 (Evonik);

[0078] 2,4-Bis(2-methoxy-5-allylphenyl)-6-allylphenol: CAS.1083166-72-6;

[0079] Formaldehyde was added in the form of a 37 wt% formaldehyde solution;

[0080] Amodimethicone: DMS-A11, DMS-A21 (Gelest), AMSD-3000 (Shin-Etsu Chemical);

[0081] Polyvinyl alcohol: PVA-1788;

[0082] Defoaming agent: TEGO Foamex 810, dosage is 0.1% of the system mass;

[0083] Polyvinyl alcohol was added in the form of a 10 wt% aqueous solution;

[0084] Non-woven glass fiber: E-glass fiber, weight 100g / m 2 , before use, preheat in an oven at 90 ° C for 1 h;

[0085] The coupling agent pre-hydrolysis solution is obtained by mixing an alcohol aqueous solution with a pH of 4.5 with the coupling agent and stirring, and pre-hydrolyzing for 10 minutes, and adding a 0.1M acetic acid-sodium acetate buffer solution to maintain the pH.

[0086] Example 1: A method for preparing a glass fiber prepreg sheet, comprising the following steps:

[0087] Step 1. Surface treatment of glass fiber:

[0088] Take non-woven glass fiber and apply coupling agent pre-hydrolyzed liquid on its surface with a coating amount of 18g / m 2 ; then dried at 80°C for 20 minutes; baked at 100°C for 25 minutes, and cooled to 50°C for use; the coupling agent pre-hydrolyzate includes the following mass components: by mass percentage, 1.5% coupling agent (KH560), 5% isopropyl alcohol, 0.05% ethylenediaminetetraacetic acid, and the balance is water;

[0089] Step 2. Preparation of impregnation solution:

[0090] (2.1) 8 g of 2,4-bis(2-methoxy-5-allylphenyl)-6-allylphenol, amino-terminated polydimethylsiloxane (DMS-A11), paraformaldehyde, 0.1% inhibitor (BHT), and 100 mL of ethanol / water mixed solution (V / V = 7:3) were mixed and stirred at 85°C under nitrogen atmosphere for 16 h. After the reaction, the water / ethanol was removed by rotary evaporation, the mixture was diluted with acetone, extracted and washed, dried, and rotary evaporation was performed again. The mixture was washed with NaHCO3 solution and dried to obtain an amino-terminated compound. The molar ratio of 2,4-bis(2-methoxy-5-allylphenyl)-6-allylphenol, amino-terminated polydimethylsiloxane, and paraformaldehyde was 1:4:1.8.

[0091] (2.2) Mix 5 g of the amino compound with 100 mL of deionized water (containing 5 wt% isopropanol), add triethylamine, adjust the pH of the reaction system to 8, and heat to 60°C; add 2,4-dihydroxyacetophenone, and stir under reflux for 30 min. After the reaction, cool to room temperature, filter, and dry to obtain the imino compound; the molar ratio of the amino group in the amino compound to the ketone group in the 2,4-dihydroxyacetophenone is 1:1.

[0092] 1 g of an imino compound, DOPO, and 0.5 mol% p-toluenesulfonic acid were mixed in 100 mL of an ethanol / water mixture (V / V = 1:4), heated to 60°C, and reacted for 10 minutes; washed, and dried to obtain a nitrogen-phosphorus-containing phenol compound; the molar ratio of the imino group to DOPO in the imino compound was 1:1;

[0093] Phenol, formaldehyde, a nitrogen-phosphorus-containing phenol compound, sodium hydroxide, and deionized water were mixed at 48° C. for 60 minutes, heated to 85° C., reacted for 90 minutes, and polyvinyl alcohol was added and the reaction continued for 90 minutes. 2,4-dimethylphenol was added and the reaction continued at 80° C. for 50 minutes. After the reaction, the mixture was cooled to 50° C., a defoamer was added, and the mixture was stirred at a low speed of 300 rpm for 10 minutes. The pH of the system was adjusted to 7 to obtain a phenolic resin with a solid content of 65%. The phenolic resin comprised the following components by weight: 20.7 parts of phenol, 23.0 parts of formaldehyde, 8 parts of a nitrogen-phosphorus-containing phenol compound, 2.6 parts of 2,4-dimethylphenol, 0.2 parts of sodium hydroxide, and 1.5 parts of polyvinyl alcohol.

[0094] (2.3) Mix the flame retardant filler with the coupling agent and water, and disperse them by high-speed shearing to obtain a flame retardant slurry. The high-speed shearing dispersion process is: shearing at 2000 rpm for 20 minutes, and then shearing at 1000 rpm for 10 minutes; mix the phenolic resin and the curing agent to obtain a resin material; mix the resin material and the flame retardant slurry, and stir and disperse them. The stirring and dispersion process is: temperature 40°C, speed 800 rpm, time 20 minutes; add the dispersant, wetting agent, coupling agent, and finally add the defoaming agent, and stir at low speed. The low-speed stirring process is: speed 300 rpm, The impregnation liquid is prepared for 10 minutes. The impregnation liquid comprises the following components: 15% resin material, 64% flame retardant material, 0.5% additive, and the balance is water, in terms of mass percentage. The resin material is a mixture of phenolic resin and curing agent, with a mass ratio of 7:10. The flame retardant material comprises the following components: 80% aluminum hydroxide, 10% magnesium hydroxide, and 10% silicon dioxide, in terms of mass percentage. The additive comprises the following components: 50% dispersant, 20% wetting agent, 10% defoaming agent, and 20% coupling agent, which is γ-aminopropyltriethoxysilane, in terms of mass percentage.

[0095] Step 3. Impregnation: The non-woven glass fiber is immersed in the impregnation liquid, and the mass ratio of the non-woven glass fiber to the impregnation liquid is 80:1000; the impregnation process conditions are: the impregnation liquid temperature is 25°C, the impregnation time is 60s; then, the impregnation is performed with a roller pressure of 0.5MPa; the glass fiber is taken out and cured, and the curing process is as follows: curing at 100°C for 10 minutes and then curing at 130°C for 6 minutes to obtain a glass fiber prepreg sheet with a resin material content of 5%.

[0096] Example 2: A method for preparing a glass fiber prepreg sheet, comprising the following steps:

[0097] Step 1. Surface treatment of glass fiber:

[0098] Take non-woven glass fiber and apply coupling agent pre-hydrolyzed liquid on its surface with a coating amount of 12g / m 2 ; then dried at 80°C for 25 minutes; baked at 110°C for 20 minutes, and cooled to 55°C for use; the coupling agent pre-hydrolyzate includes the following mass components: by mass percentage, 2.2% coupling agent (KH560), 7.5% isopropyl alcohol, 0.08% ethylenediaminetetraacetic acid, and the balance is water;

[0099] Step 2. Preparation of impregnation solution:

[0100] (2.1) 10 g of 2,4-bis(2-methoxy-5-allylphenyl)-6-allylphenol, amino-terminated polydimethylsiloxane (DMS-A21), paraformaldehyde, 0.1% inhibitor (BHT), and 100 mL of ethanol / water mixed solution (V / V = 7:3) were mixed and stirred at 88°C under nitrogen atmosphere for 14 h. After the reaction, the water / ethanol was removed by rotary evaporation, the mixture was diluted with acetone, extracted and washed, dried, and rotary evaporation was repeated. The mixture was washed with NaHCO3 solution and dried to obtain an amino-terminated compound. The molar ratio of 2,4-bis(2-methoxy-5-allylphenyl)-6-allylphenol, amino-terminated polydimethylsiloxane, and paraformaldehyde was 1:4.2:2.0.

[0101] (2.2) 8 g of the amino compound was mixed with 100 mL of deionized water (containing 5 wt% isopropanol), triethylamine was added, the pH of the reaction system was adjusted to 8.5, and the temperature was raised to 65°C. 2,4-dihydroxyacetophenone was added, and the mixture was stirred and refluxed for 25 min. After the reaction, the mixture was cooled to room temperature, filtered, and dried to obtain an imino compound. The molar ratio of the amino group in the amino compound to the ketone group in the 2,4-dihydroxyacetophenone was 1:1.

[0102] 2 g of an imino compound, DOPO, and 0.8 mol% p-toluenesulfonic acid were mixed in 100 mL of an ethanol / water mixture (V / V = 1:4), heated to 70°C, and reacted for 12 minutes; washed, and dried to obtain a nitrogen-phosphorus-containing phenol compound; the molar ratio of the imino group to DOPO in the imino compound was 1:1;

[0103] Phenol, formaldehyde, a nitrogen-phosphorus-containing phenol compound, sodium hydroxide, and deionized water were mixed at 52° C. for 60 minutes, heated to 88° C., reacted for 75 minutes, and polyvinyl alcohol was added and the reaction continued for 105 minutes. 2,4-dimethylphenol was added and the reaction continued at 82° C. for 70 minutes. After the reaction, the mixture was cooled to 50° C., a defoamer was added, and the mixture was stirred at a low speed of 300 rpm for 10 minutes. The pH of the system was adjusted to 7.5 to obtain a phenolic resin with a solid content of 75%. The phenolic resin comprised the following components by weight: 19.3 parts of phenol, 20.6 parts of formaldehyde, 9 parts of a nitrogen-phosphorus-containing phenol compound, 3.3 parts of 2,4-dimethylphenol, 0.3 parts of sodium hydroxide, and 1.8 parts of polyvinyl alcohol.

[0104] (2.3) Mix the flame retardant filler with the coupling agent and water, and disperse them at high speed shear to obtain a flame retardant slurry. The high speed shear dispersion process is: shear at 2000 rpm for 20 minutes, and then shear at 1000 rpm for 10 minutes; mix the phenolic resin and the curing agent to obtain a resin material; mix the resin material and the flame retardant slurry, and stir and disperse them. The stirring and dispersion process is: temperature 45°C, speed 1000 rpm, time length 25 minutes; add dispersant, wetting agent, coupling agent, and finally add defoaming agent, and stir at low speed. The low speed stirring process is: speed 450 rpm, time length 15 min, to obtain an impregnation solution; the impregnation solution comprises the following components: by mass percentage, 16% resin material, 65% flame retardant material, 1% additive, and the balance is water; the resin material is a mixture of phenolic resin and curing agent, with a mass ratio of 7:10; the flame retardant material comprises the following components: by mass percentage, 85% aluminum hydroxide, 7.5% magnesium hydroxide and 7.5% silicon dioxide; the additive comprises the following components: by mass percentage, 45% dispersant, 25% wetting agent, 15% defoaming agent and 25% coupling agent is γ-(2,3-epoxypropoxy)propyltrimethoxysilane;

[0105] Step 3. Impregnation: The non-woven glass fiber is immersed in the impregnation liquid, and the mass ratio of the non-woven glass fiber to the impregnation liquid is 115:1000; the impregnation process conditions are: the impregnation liquid temperature is 27°C, the impregnation time is 52s; then, the impregnation is performed with a roller pressure of 0.4MPa; the glass fiber is taken out and cured, and the curing process is as follows: curing at 110°C for 9min, and then curing at 140°C for 56min to obtain a glass fiber prepreg sheet with a resin material content of 7.5wt%.

[0106] Example 3: A method for preparing a glass fiber prepreg sheet, comprising the following steps:

[0107] Step 1. Surface treatment of glass fiber:

[0108] Take non-woven glass fiber and apply coupling agent pre-hydrolyzed liquid on its surface with a coating amount of 9g / m 2; then dried at 80°C for 30 minutes; baked at 120°C for 15 minutes, and cooled to 60°C for use; the coupling agent pre-hydrolyzate includes the following mass components: by mass percentage, 3.0% coupling agent (KH560), 10% isopropyl alcohol, 0.10% ethylenediaminetetraacetic acid, and the balance is water;

[0109] Step 2. Preparation of impregnation solution:

[0110] (2.1) 12 g of 2,4-bis(2-methoxy-5-allylphenyl)-6-allylphenol, amino-terminated polydimethylsiloxane (AMSD-3000), paraformaldehyde, 0.1% inhibitor (BHT), and 100 mL of ethanol / water mixed solution (V / V = 7:3) were mixed and stirred at 90°C under nitrogen atmosphere for 12 h. After the reaction, the water / ethanol was removed by rotary evaporation, the mixture was diluted with acetone, extracted and washed, dried, and rotary evaporation was repeated. The mixture was washed with NaHCO3 solution and dried to obtain an amino-terminated compound. The molar ratio of 2,4-bis(2-methoxy-5-allylphenyl)-6-allylphenol, amino-terminated polydimethylsiloxane, and paraformaldehyde was 1:4.5:2.2.

[0111] (2.2) Mix 10 g of the amino compound with 100 mL of deionized water (containing 5 wt% isopropanol), add triethylamine, adjust the pH of the reaction system to 9, and heat to 70°C; add 2,4-dihydroxyacetophenone, and stir under reflux for 20 min. After the reaction, cool to room temperature, filter, and dry to obtain an imino compound; the molar ratio of the amino group in the amino compound to the ketone group in the 2,4-dihydroxyacetophenone is 1:1.

[0112] 3 g of an imino compound, DOPO, and 1.0 mol% p-toluenesulfonic acid were mixed in 100 mL of an ethanol / water mixture (V / V = 1:4), heated to 80°C, and reacted for 15 minutes; washed and dried to obtain a nitrogen-phosphorus-containing phenol compound; the molar ratio of the imino group to DOPO in the imino compound was 1:1;

[0113] Phenol, formaldehyde, a nitrogen-phosphorus-containing phenol compound, sodium hydroxide, and deionized water were mixed at 55° C. for 60 minutes, heated to 90° C., reacted for 60 minutes, and polyvinyl alcohol was added and the reaction continued for 120 minutes. 2,4-dimethylphenol was added and the reaction continued at 85° C. for 90 minutes. After the reaction, the mixture was cooled to 50° C., a defoaming agent was added, and the mixture was stirred at a low speed of 300 rpm for 10 minutes. The pH of the system was adjusted to 8 to obtain a phenolic resin with a solid content of 85%. The phenolic resin comprised the following components by weight: 18.0 parts of phenol, 18.2 parts of formaldehyde, 10 parts of a nitrogen-phosphorus-containing phenol compound, 4.0 parts of 2,4-dimethylphenol, 0.5 parts of sodium hydroxide, and 2.0 parts of polyvinyl alcohol.

[0114] (2.3) Mix the flame retardant filler with the coupling agent and water, and disperse them by high-speed shearing to obtain a flame retardant slurry. The high-speed shearing dispersion process is: shearing at 2000 rpm for 20 minutes, and then shearing at 1000 rpm for 10 minutes; mix the phenolic resin and the curing agent to obtain a resin material; mix the resin material and the flame retardant slurry, and stir and disperse them. The stirring and dispersion process is: temperature 50°C, speed 1200 rpm, time 30 minutes; add dispersant, wetting agent, coupling agent, and finally add defoaming agent, and stir at low speed. The low-speed stirring process is: speed 600 rpm m, for 20 minutes, to obtain an impregnation solution; the impregnation solution comprises the following components: by mass percentage, 18% resin material, 66% flame retardant material, 1.5% additive, and the balance is water; the resin material is a mixture of phenolic resin and curing agent, with a mass ratio of 7:10; the flame retardant material comprises the following components: by mass percentage, 90% aluminum hydroxide, 5% magnesium hydroxide and 5% silicon dioxide; the additive comprises the following components: by mass percentage, 30% dispersant, 30% wetting agent, 20% defoaming agent and 20% coupling agent is γ-mercaptopropyltriethoxysilane;

[0115] Step 3. Impregnation: The non-woven glass fiber is immersed in the impregnation liquid, and the mass ratio of the non-woven glass fiber to the impregnation liquid is 150:1000; the impregnation process conditions are: the impregnation liquid temperature is 30°C, the impregnation time is 60s; then, the impregnation is performed with a roller pressure of 0.2MPa; the glass fiber is taken out and cured, and the curing process is as follows: curing at 120°C for 8min, and then curing at 150°C for 4min to obtain a glass fiber prepreg sheet with a resin material content of 10wt%.

[0116] Comparative Example 1: A method for preparing a glass fiber prepreg sheet, comprising the following processes:

[0117] Step 2. Replace the amino compound with amino-terminated polydimethylsiloxane (DMS-A11). The phenolic resin includes the following components by mass: 20.7 parts of phenol, 23.0 parts of formaldehyde, 2.4 parts of nitrogen-phosphorus-containing phenol compounds, 2.6 parts of nitrogen-phosphorus-containing phenol compounds, 0.2 parts of sodium hydroxide, and 1.5 parts of polyvinyl alcohol. The other steps are the same as in Example 1 to obtain a glass fiber prepreg sheet.

[0118] Comparative Example 2: A method for preparing a glass fiber prepreg sheet, comprising the following processes:

[0119] Step 2. The phenolic resin includes the following components by weight: 20.7 parts of phenol, 23.0 parts of formaldehyde, 0.2 parts of 2,4-dihydroxyacetophenone, 2.6 parts of 2,4-xylenol, 0.2 parts of sodium hydroxide, and 1.5 parts of polyvinyl alcohol;

[0120] The other steps are the same as those in Example 1 to obtain a glass fiber prepreg sheet.

[0121] Comparative Example 3: A method for preparing a glass fiber prepreg sheet, comprising the following processes:

[0122] Step 1. Surface treatment of glass fiber: preheat in an oven at 90°C for 1 hour;

[0123] Step 2. The phenolic resin includes the following components by weight: 20.7 parts of phenol, 23.0 parts of formaldehyde, 2.6 parts of 2,4-dimethylphenol, 0.2 parts of sodium hydroxide, and 1.5 parts of polyvinyl alcohol;

[0124] Step 3 is the same as in Example 1, obtaining a glass fiber prepreg sheet.

[0125] Experiment: The glass fiber prepreg sheets obtained in Examples 1-3 and Comparative Examples 1-3 were used to prepare samples, and their properties were tested and the test results were recorded:

[0126] Mechanical properties test: ASTM D638 was used as the reference standard to test the tensile strength of the specimens at a tensile rate of 5 mm / min. ASTM D790 was used as the reference standard to test the flexural strength of the specimens, with specimen dimensions of 80 mm × 10 mm × 4 mm, a span-to-thickness ratio of 16:1, and an indentation rate of 2 mm / min. ASTM D256 was used as the reference standard to test the impact properties of notched specimens.

[0127] Flame retardant and fire performance test: Based on GB / T 2406 as the reference standard, the limiting oxygen index (LOI) of the sample is tested, and the sample size is 100mm×6.5mm×3mm; based on UL94 as the reference standard, the UL94 vertical burning grade of the sample is tested, V-0 (afterflame ≤10s, no molten droplets ignite absorbent cotton), V-1 (afterflame ≤30s), and V-2 (with molten droplets ignite); based on GB / T 9978.1 as the reference standard, the fire resistance limit of the sample is tested, and the sample size is 1000mm×1000mm×10mm;

[0128] Water resistance test: GB / T 10703 is used as the reference standard to test the water absorption rate of the sample. The sample size is 50mm×50mm. The experiment uses 23℃ distilled water and the water absorption time is 48h.

[0129] Formaldehyde emission test: Based on EN 717-1 and GB 18580 as reference standards, the formaldehyde emission level of the sample is tested. The experimental environment is: temperature 23±0.5°C, relative humidity 45±3%; sample size is 1m2 (double-sided exposure), air exchange rate is 1.0 times / h, and the test duration is 72 hours.

[0130] Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Tensile strength (MPa) 284 303 289 255 211 180 Flexural strength (MPa) 320 345 376 270 225 200 <![CDATA[Impact strength (kJ / m 2 )]]> 46.5 49.2 55.0 36.0 25.2 22.0 LOI (%) 32.5 35.0 37.5 28.5 24.0 22.0 UL94 rating V-0 V-0 V-0 V-1 V-2 / Fire resistance limit (min) ＞90 ＞90 80 50 30 20 Water absorption (%) 0.85 0.62 0.41 1.53 2.07 3.15 Formaldehyde emission level E0 E0 ENF E1 E1 E2

[0131] According to the data in the above table, we can clearly draw the following conclusions:

[0132] The glass fiber prepreg sheets obtained in Examples 1-3 were compared with those obtained in Comparative Examples 1-3. The test results show that:

[0133] Compared to the comparative examples, the glass fiber prepregs obtained in Examples 1-3 exhibited higher tensile strength, flexural strength, and impact strength, as well as better LOI, UL94 rating, fire resistance, formaldehyde emission rating, and formaldehyde emission rating. This fully demonstrates that the present invention improves the mechanical properties, flame retardancy, water resistance, and formaldehyde emission performance of the prepared glass fiber prepregs.

[0134] Compared to Example 1, Comparative Example 1 replaced the amino compound used in the phenolic resin preparation process with amino-terminated polydimethylsiloxane; Comparative Example 2 replaced the nitrogen-phosphorus phenol compound with 2,4-dihydroxyacetophenone; and Comparative Example 3 used a different surface treatment process for the glass fiber, and omitted 2,4-dimethylphenol from the phenolic resin component. The glass fiber prepregs obtained in Comparative Examples 1-3 showed deterioration in tensile strength, flexural strength, and impact strength, and decreased LOI, UL94 rating, fire resistance, formaldehyde emission rating, and formaldehyde emission rating. This indicates that the present invention's design of the glass fiber prepreg preparation process and its components can promote comprehensive improvements in mechanical properties, flame retardancy, water resistance, and formaldehyde emission.

[0135] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced therein.

Claims

1. A glass fiber prepreg sheet, characterized in that: It is formed by dipping non-woven glass fiber in the impregnation liquid, taking it out, and curing it; The impregnation liquid comprises the following components: in mass percentage, 15-18% of resin material, 64-66% of flame retardant material, 0.5-1.5% of auxiliary agent, and the balance is water.

2. The glass fiber prepreg sheet according to claim 1, characterized in that: The resin material is a mixture of phenolic resin and curing agent, with a mass ratio of (5-8):

10.

3. The glass fiber prepreg sheet according to claim 1, characterized in that: The flame retardant material comprises the following components: in mass percentage, 80-90% of aluminum hydroxide, 5-10% of magnesium hydroxide and 5-10% of silicon dioxide.

4. The method for preparing a glass fiber prepreg sheet according to any one of claims 1 to 3, characterized in that: Including the following processes: Step 1. Preparation of impregnation solution: Mixing the flame retardant filler with the coupling agent and water, and dispersing the mixture by high-speed shearing to obtain a flame retardant slurry; mixing phenolic resin and curing agent to obtain a resin material; Mix the resin material and flame retardant slurry, stir and disperse; add dispersant, wetting agent, coupling agent, and finally add defoaming agent, stir at low speed to obtain impregnation liquid; Step 2. Dipping: The non-woven glass fiber is immersed in the impregnation liquid, taken out, and solidified to obtain a glass fiber prepreg sheet.

5. The method for preparing a glass fiber prepreg sheet according to claim 4, wherein: The phenolic resin is prepared by the following process: (1) Mixing an amino compound and deionized water, adding triethylamine, adjusting the pH of the reaction system to 8-9, and heating to 60-70°C; adding 2,4-dihydroxyacetophenone, stirring and refluxing for 20-30 minutes to obtain an imino compound; Mixing an imino compound, DOPO, and p-toluenesulfonic acid in an ethanol / water mixed solution, heating to 60-80° C., and reacting for 10-15 minutes to obtain a nitrogen-phosphorus-containing phenol compound; (2) Phenol, formaldehyde, nitrogen-phosphorus-containing phenol compound, sodium hydroxide and deionized water are mixed at a temperature of 48-55°C, heated to 85-90°C, reacted for 60-90 minutes, polyvinyl alcohol is added, and the reaction is continued for 90-120 minutes; 2,4-dimethylphenol is added, and the reaction is carried out at a temperature of 80-85°C for 50-90 minutes to obtain a phenolic resin.

6. The method for preparing a glass fiber prepreg sheet according to claim 5, characterized in that: The amino compound is prepared by the following process: 2,4-bis(2-methoxy-5-allylphenyl)-6-allylphenol, amino-terminated polydimethylsiloxane, paraformaldehyde, a polymerization inhibitor and an ethanol / water mixed solution are mixed, and under the protection of a nitrogen atmosphere, the mixture is stirred and reacted at a temperature of 85 to 90° C. for 12 to 16 hours to obtain an amino-terminated compound.

7. The method for preparing a glass fiber prepreg sheet according to claim 5, wherein: In step (1), the molar ratio of the amino group in the amino compound, the ketone group in 2,4-dihydroxyacetophenone, and potassium hydroxide is 1:1:1; In step (1), the molar ratio of the imino group to DOPO in the imino compound is 1:

1.

8. The method for preparing a glass fiber prepreg sheet according to claim 5, wherein: In step (2), the phenolic resin includes the following components by mass: 16.5 to 20.7 parts of phenol, 18.2 to 23.0 parts of formaldehyde, 5 to 12 parts of nitrogen-phosphorus-containing phenol compounds, 2.6 to 4.0 parts of 2,4-dimethylphenol, and 0.3 to 0.8 part of sodium hydroxide.

9. The method for preparing a glass fiber prepreg sheet according to claim 6, wherein: The molar ratio of 2,4-bis(2-methoxy-5-allylphenyl)-6-allylphenol, amino-terminated polydimethylsiloxane, and paraformaldehyde is 1:(4.0-4.5):(1.8-2.2).

10. The method for preparing a glass fiber prepreg sheet according to claim 4, characterized in that: The non-woven glass fiber is surface modified, and the specific process is as follows: Take non-woven glass fiber, apply coupling agent pre-hydrolyzed liquid on its surface; then dry at 80℃ for 20-30min, and bake at 100-120℃ for 15-25min.