Long-acting stable water-based impregnating compound for preparing elastic basalt fiber

Abstract

The invention provides a long-acting stable water-based impregnating compound for preparing elastic basalt fibers. The long-acting stable water-based impregnating compound is prepared by stirring the following raw materials in percentage by mass: 2-4% of terminated polyurethane, 2-4% of epoxy resin, 0.3-0.8% of a coupling agent, 0.2-0.8% of a lubricant and the balance of deionized water. According to the technology, an isocyanate group of polyurethane is protected, and the impregnating compound emulsion can be stored for a long time without self-polymerization. The impregnating compound has good hydrophilicity and does not need to be added with an emulsifier. When the impregnating compound is coated on the basalt fiber, the strength, elasticity and alkali resistance of the fiber can be greatly enhanced. The deblocking temperature of the impregnating compound is consistent with the residual temperature in the basalt wire drawing process, in-situ polymerization can be realized, sizing is facilitated, and a uniformly coated polymer film is formed, so that the properties of basalt fibers are improved.

Description

Technical Field

[0001] The invention relates to the technical field of sizing agents for basalt continuous fibers, and specifically to a sizing agent blended with a blocked polyurethane and an epoxy resin, which can be stored for a long time, unblocked at the right time, sized synchronously with wire drawing, and polymerized in situ. The invention is a type of long-lasting and stable water-based sizing agent, and is used for the preparation of elastic basalt fibers. Background Art

[0002] Commonly used basalt fiber sizing agents include polyester emulsion, epoxy emulsion and polyurethane emulsion. Polyester emulsion is not resistant to acid and alkali. At present, polyester emulsion is rarely used as a sizing agent in the production of basalt continuous fiber or glass fiber because of its poor water resistance. Epoxy emulsion has the advantages of strong adhesion and high strength, but its wear resistance and flexibility are poor. The fiber impregnated has poor flexibility, making it difficult to use the fiber in the knitting field. Polyurethane emulsion has high elasticity, good wear resistance and excellent adhesion, and can achieve the coating of inorganic fibers. However, as a film-forming agent, polyurethane emulsion is unstable in high temperature and acid-base environment, and often forms self-polymerization, resulting in emulsion sedimentation. At present, the instability of polyurethane emulsion in transportation, storage, use and other links limits its widespread application. Blending epoxy emulsion and polyurethane emulsion and applying a suitable end-capping agent can greatly improve the stability of the sizing agent. The blocked polyurethane emulsion is applied to the hot basalt fiber surface. The residual heat from fiber drawing can be used to deblock the polyurethane and polymerize it in situ with the epoxy groups. This not only increases the number of polar functional groups on the basalt fiber surface, but also allows the hydroxyl groups on the fiber surface to form hydrogen bonds with the hydrophilic groups in the polyurethane solution, which helps to enhance the interface strength between the fiber and the resin. While improving the mechanical properties of the material, an elastic fiber membrane is formed, which is beneficial to the downstream application of basalt continuous fibers.

[0003] Patent XN201210401128 A sizing agent for surface modification of basalt fibers is disclosed. This sizing agent uses polyurethane and a water-soluble epoxy resin adjuvant, and uses other substances as the main film-forming agent. Although this sizing agent is easy to prepare, its application range is limited. It is only used for chopped basalt fibers and is used in construction fields such as asphalt reinforcement, without involving the improvement of the elasticity of basalt fibers. Patent XN 117185676A discloses a sizing agent for basalt fiber composites and its preparation method. This sizing agent uses modified epoxy resin as the film-forming agent and waterborne polyurethane as the dispersant. However, this sizing agent has poor stability and is prone to self-polymerization, and can only be "prepared and used immediately", making it difficult for long-distance transportation and storage. Patent XN 117342804B discloses a preparation method of a sizing agent for improving the high-temperature and high-humidity performance of basalt fiber composites. This sizing agent uses bisphenol A epoxy resin emulsion, acrylic resin emulsion, and polyurethane resin emulsion as the film-forming agent, which can improve the surface defects of the fibers and enhance the mechanical properties. However, the patent does not mention its alkali resistance and elasticity. Patent XN 113511821B discloses a sizing agent for basalt fibers used in electronic fabrics and its preparation method. The waterborne polyurethane and epoxy resin in this sizing agent can form a film on the surface of basalt fibers, improving the bonding force on the surface of basalt fibers. However, the flexibility of the fibers cannot be improved because the patent fails to control a reasonable temperature and lacks the step of in-situ polymerization. Patent XN 109762131 discloses a siloxane blocking agent and its preparation method, and uses this blocking agent in a photo-wet dual-cured polyurethane pressure-sensitive adhesive. Although this blocking agent will reduce the water solubility of polyurethane, a large amount of organic solvents are required during the synthesis process, resulting in high costs. The use of organic solvents does not meet environmental protection requirements, and this technology is not advocated in industrial production. Patent XN 1968984B discloses a blocked polyurethane prepolymer that can be used in a coating composition, and directly applies the blocked polyurethane prepolymer to the coating. However, it does not consider the deblocking process of the blocked polyurethane, nor does it consider the actual working conditions of basalt fiber production and in-situ polymerization. Therefore, this patent cannot provide an effective solution. XN 101641303A discloses a sizing composition for glass fibers, including a silane coupling agent and one or more blocked polyurethane film-forming agents. However, the affinity between the fibers and the resin matrix is limited, and the strength and elasticity of the sized fibers both need to be improved. This process also does not clearly give the stability of the sizing agent.

[0004] Based on the characteristics of basalt fiber itself, a special sizing agent for enhancing its mechanical properties, resistance to heat and humidity, elasticity, etc. remains to be developed. Therefore, in the present invention, the isocyanate groups of polyurethane are blocked with a blocking agent to make it temporarily inactivated, and a long-lasting and stable sizing agent emulsion is obtained. Applying this emulsion to hot basalt fiber, especially taking advantage of the residual heat of in-situ wire drawing, can achieve the deblocking of the blocked polyurethane. After deblocking, the polyurethane forms a crosslinked network with epoxy resin, and a long-lasting and stable basalt fiber sizing agent can be prepared. The blocked polyurethane used in this sizing agent forms two chain ends, a hydrophobic end and a hydrophilic end, in the whole macromolecule, which is similar to a macromolecular surfactant and has excellent wettability and permeability to basalt fiber materials. This sizing agent does not require an external emulsifier, can achieve uniform emulsification, and can be long-term stable during transportation and storage without self-polymerization. The deblocking temperature of this sizing agent is suitable for the residual heat during basalt wire drawing, and the deblocked monomers can polymerize with other multi-components in the emulsion to form a dense coating film, realizing in-situ sizing of basalt fiber. The obtained basalt fiber has alkali resistance and good elasticity, expanding the application fields of basalt fiber while improving its mechanical properties. Summary of the Invention

[0005] The present invention aims to solve the disadvantage of unstable existing sizing agents and provides a long-lasting and stable water-based sizing agent for preparing elastic basalt fiber. This blocked sizing agent does not require an external emulsifier, can be uniformly emulsified in an aqueous system, and the emulsion can be long-term stable at room temperature. The deblocking temperature is consistent with the residual heat of basalt fiber wire drawing. While realizing the deblocking of polyurethane, the deblocked monomers and other components achieve in-situ polymerization to form a dense coating film. The basalt fiber coated with this sizing agent has good elasticity and improves the mechanical properties of continuous basalt fiber.

[0006] The present invention is achieved through the following technical solutions:

[0007] A long-lasting and stable water-based sizing agent for preparing elastic basalt fiber, calculated by mass fraction, includes the following components: blocked polyurethane 2 - 4%, epoxy resin 2 - 4%, coupling agent 0.3 - 0.8%, lubricant 0.2 - 0.8%, and the balance is deionized water;

[0008] The raw materials of the blocked polyurethane are prepared from deionized water, blocking agent, accelerator and the following components by mass fraction: polyether polyol 30 - 50%, small molecule alcohol 4 - 8%, diisocyanate 30 - 40%, chain extender 2 - 6%, catalyst 2 - 6%;

[0009] Further, the polyether polyol includes one or more of polypropylene glycol, polyethylene glycol, and polytetrahydrofuran;

[0010] The small molecule alcohol includes one or more of ethylene glycol, 1,4-butanediol, 1,6-hexanediol, and pentaerythritol;

[0011] The diisocyanate includes one or more of isophorone diisocyanate and toluene diisocyanate;

[0012] The chain extender includes one or more of N-methyl diethanolamine, triethylamine, and N,N-diisopropylaniline;

[0013] The catalyst is dibutyltin dilaurate;

[0014] The capping agent is sodium bisulfite;

[0015] The accelerator is sodium sulfite;

[0016] The epoxy resin includes one or more of water-soluble epoxy resin and E44;

[0017] The coupling agent includes one or more of KH550, KH560, and KH570;

[0018] The lubricant includes one or more of mineral oil, polyethylene glycol 400 monooleate, and polyoxyethylene stearate;

[0019] Furthermore, the preparation method of the capped polyurethane is as follows:

[0020] ∑1 By mass fraction, 40-50% of polyether polyol and 4-8% of small molecule alcohol are mixed at 100-110 °C to obtain a mixture;

[0021] ∑2 By mass fraction, 30-40% of diisocyanate is mixed with the mixture obtained in ∑1 and synthesized at 70-90 °C for a reaction time of 2-3 η

[0022] ∑3 By mass fraction, 2-6% of chain extender and 2-6% of catalyst are dropped into the system of ∑2, the reaction temperature is 40-50 °C, and the reaction time is 0.5-1 η to obtain a polyurethane prepolymer;

[0023] ∑4 The capping agent and accelerator are mixed with the prepolymer in ∑3, the capping time is 0.5-1 η, and the capping temperature is 20 °C to obtain a capped polyurethane prepolymer;

[0024] ∑5 Deionized water is mixed with the prepolymer obtained in ∑4 at a ratio of 1:10 for emulsification, and the emulsification time is 1-3 η to obtain a capped polyurethane emulsion;

[0025] The present invention also provides a long-acting and stable water-based sizing agent for preparing elastic basalt fibers and an in-situ reaction method, including the following steps:

[0026] ∑1 By mass fraction, 2-4% of the blocked polyurethane in Claim 2, 0.3-0.8% of the coupling agent, and 0.2-0.8% of the lubricant are stirred for 2-3η, the reaction temperature is 65°C, and finally 2-4% of the epoxy resin is added to obtain a composite basalt fiber sizing agent of blocked polyurethane and epoxy resin;

[0027] ∑2 The sizing agent in ∑1 is used to in-situ impregnate the basalt fiber, and in-situ sizing is applied at a position of 110-150°X.

[0028] Furthermore, ∑2 uses the sizing agent in ∑1 to in-situ impregnate the basalt fiber. Below the basalt fiber spinning outlet, at a position where the temperature is 110-150°X, the sizing agent is applied, causing the blocked polyurethane to deblock, obtaining monomers, and in-situ polymerizing with other multi-components in the emulsion to form a dense coating film, realizing in-situ sizing of the basalt fiber.

[0029] Compared with the prior art, the present invention has the following advantages:

[0030] 1. A long-acting and stable water-based sizing agent for preparing elastic basalt fibers obtained by the present invention uses blocked polyurethane. The product formed by the blocking agent sodium bisulfite and isocyanate is water-soluble. Therefore, the obtained sizing agent has excellent wettability and permeability to fiber materials, does not require an additional emulsifier, simplifies the process, and the sizing agent can be long-term stable during transportation and storage;

[0031] 2. A long-acting and stable water-based sizing agent for preparing elastic basalt fibers provided by the present invention utilizes the residual temperature of basalt fiber drawing to promote the deblocking of blocked polyurethane and cross-link with other components to form a stable network structure, improving the mechanical properties and alkali resistance of basalt fibers.

[0032] 3. A long-acting and stable water-based sizing agent for preparing elastic basalt fibers provided by the present invention releases -NXO groups after the deblocking of polyurethane. These groups can form in-situ polymerization with fiber active groups to generate a coating film with good elasticity on the surface of basalt fibers. This film not only improves the bundling property of fibers but also enhances the interfacial bonding force between fibers and the resin matrix. Description of the Drawings

[0033] Figure 1 This is the SEM image of the bare basalt fiber of the present invention, proving that the fiber surface is smooth;

[0034] Figure 2 This is the SEM image of the basalt fiber treated with the sizing agent of the present invention, proving that the sizing agent can in-situ polymerize on the fiber surface;

[0035] Figure 3It is a micrograph of the knotting of basalt fiber bare yarn and the fiber after applying the sizing agent of the present invention, which proves that the sizing agent can improve the elasticity of continuous basalt fiber. Detailed implementation mode

[0036] On the premise of the technical solution of the present invention, any modification or change that is easily achievable by those of ordinary skill in the art to the present invention will fall within the scope of the claims of the present invention.

[0037] Example 1:

[0038] Add 12 μL of polypropylene glycol and 2 μL of 1,4-butanediol into a three-necked flask, heat up to 100 - 110 °C, evacuate three times, and heat for 1 h; after the evacuation is completed, introduce nitrogen, cool down to 70 - 80 °C, and slowly add 12 μL of isophorone diisocyanate, which is added in three portions within 1 h, and keep heating at a constant temperature for 3 h; cool down to 40 °C, add an appropriate amount of anhydrous acetone to reduce the viscosity, then add 1 μL of N-methyl diethanolamine and 1 μL of dibutyltin dilaurate for catalysis, and react for 3 h; add glacial acetic acid to neutralize the reaction for 0.5 h to obtain a polyurethane prepolymer; add sodium bisulfite solution, sodium sulfite solution and acetone to the polyurethane prepolymer, and carry out a capping reaction at 20 °C for 1 h to obtain a capped polyurethane prepolymer; then stir the capped polyurethane prepolymer at high speed, add an appropriate amount of deionized water at the same time, emulsify for 3 h, and finally heat up to 50 - 60 °C, and distill off acetone under reduced pressure to obtain a capped polyurethane.

[0039] Stir 30 g of the above-mentioned capped polyurethane, 2.5 g of mineral oil, 8 g of KH570 coupling agent and 900 g of deionized water at 65 °C for 2 - 3 h, and finally add 30 g of water-soluble epoxy resin to obtain a sizing agent for composite basalt fiber of capped polyurethane and epoxy resin. Size the basalt fiber with the obtained sizing agent and carry out in-situ polymerization at a position of 110 - 150 °C to obtain elastic basalt fiber.

[0040] Example 2:

[0041] Add 12 μL of polypropylene glycol and 2 μL of 1,4-butanediol into a three-necked flask, heat up to 100 - 110 °C, evacuate the air three times, and heat for 1 h; after the evacuation ends, introduce nitrogen, cool down to 70 - 80 °C, slowly add 12 μL of isophorone diisocyanate, add it in three portions within 1 h, and keep heating at a constant temperature for 3 h; cool down to 40 °C, add an appropriate amount of anhydrous acetone to reduce the viscosity, then add 1 μL of N-methyl diethanolamine and 1 μL of dibutyltin dilaurate for catalysis, and react for 3 h; add glacial acetic acid and neutralize the reaction for 0.5 h to obtain a polyurethane prepolymer; add sodium bisulfite solution, sodium sulfite solution and acetone into the polyurethane prepolymer, carry out end-capping reaction at 20 °C for 1 h to obtain an end-capped polyurethane prepolymer; then stir the end-capped polyurethane prepolymer at high speed, add an appropriate amount of deionized water at the same time, emulsify for 3 h, and finally heat up to 50 - 60 °C, and distill off acetone under reduced pressure to obtain end-capped polyurethane.

[0042] Stir 30 g of the above-mentioned end-capped polyurethane, 2.5 g of polyethylene glycol monooleate, 8 g of KH570 coupling agent and 900 g of deionized water at 65 °C for 2 - 3 h, and finally add 10 g of epoxy resin E44 to obtain a composite sizing agent for basalt fibers composed of end-capped polyurethane and epoxy resin; finally, size the basalt fibers with the obtained sizing agent and carry out in-situ polymerization at a position of 110 - 150 °C to obtain elastic basalt fibers.

[0043] Example 3:

[0044] Add 12 μL of polypropylene glycol and 2 μL of 1,4-butanediol into a three-necked flask, heat up to 100 - 110 °C, evacuate the air three times, and heat for 1 h; after the evacuation ends, introduce nitrogen, cool down to 70 - 80 °C, slowly add 12 μL of isophorone diisocyanate, add it in three portions within 1 h, and keep heating at a constant temperature for 3 h; cool down to 40 °C, add an appropriate amount of anhydrous acetone to reduce the viscosity, then add 1 μL of N-methyl diethanolamine and 1 μL of dibutyltin dilaurate for catalysis, and react for 3 h; add glacial acetic acid and neutralize the reaction for 0.5 h to obtain a polyurethane prepolymer; add sodium bisulfite solution, sodium sulfite solution and acetone into the polyurethane prepolymer, carry out end-capping reaction at 20 °C for 1 h to obtain an end-capped polyurethane prepolymer; then stir the end-capped polyurethane prepolymer at high speed, add an appropriate amount of deionized water at the same time, emulsify for 3 h, and finally heat up to 50 - 60 °C, and distill off acetone under reduced pressure to obtain end-capped polyurethane.

[0045] Stir 30 g of the above-mentioned end-capped polyurethane, 2.5 g of polyethylene glycol monooleate, 8 g of KH570 coupling agent and 900 g of deionized water at 65 °C for 2 - 3 h, and finally add 8 g of epoxy resin E44 to obtain a composite sizing agent for basalt fibers composed of end-capped polyurethane and epoxy resin. Size the basalt fibers with the obtained sizing agent and carry out in-situ polymerization at a position of 110 - 150 °C to obtain elastic basalt fibers.

[0046] Example 4:

[0047] Add 12 μL of polypropylene glycol and 2 μL of 1,4-butanediol into a three-necked flask, heat up to 100 - 110 °C, evacuate three times, and heat for 1 h; after the evacuation ends, introduce nitrogen, cool down to 70 - 80 °C, slowly add 12 μL of isophorone diisocyanate, add it in three portions within 1 h, and heat at a constant temperature for 3 h; cool down to 40 °C, add an appropriate amount of anhydrous acetone to reduce the viscosity, then add 1 μL of N-methyldiethanolamine and 1 μL of dibutyltin dilaurate for catalysis, and react for 3 h; add glacial acetic acid and neutralize the reaction for 0.5 h to obtain a polyurethane prepolymer; add sodium bisulfite solution, sodium sulfite solution and acetone into the polyurethane prepolymer, and carry out end-capping reaction at 20 °C for 1 h to obtain an end-capped polyurethane prepolymer; then stir the end-capped polyurethane prepolymer at high speed, add an appropriate amount of deionized water at the same time, emulsify for 3 h, and finally heat up to 50 - 60 °C, and distill off acetone under reduced pressure to obtain end-capped polyurethane.

[0048] Stir 30 g of the above-mentioned end-capped polyurethane, 2.4 g of mineral oil, 8 g of KH550 coupling agent and 900 g of deionized water at 65 °C for 2 - 3 h, and finally add 30 g of water-soluble epoxy resin to obtain a composite sizing agent of end-capped polyurethane and epoxy resin. Size the basalt fiber with the obtained sizing agent and carry out in-situ polymerization at a position of 110 - 150 °C to obtain elastic basalt fiber.

[0049] Comparative Example 1:

[0050] Add 12 μL of polypropylene glycol and 2 μL of 1,4-butanediol into a three-necked flask, heat up to 100 - 110 °C, evacuate three times, and heat for 1 h; after the evacuation ends, introduce nitrogen, cool down to 70 - 80 °C, add 12 μL of isophorone diisocyanate, add it in three portions within 1 h, and heat at a constant temperature for 3 h; cool down to 40 °C, add an appropriate amount of anhydrous acetone to reduce the viscosity, then add 1 μL of N-methyldiethanolamine and 1 μL of dibutyltin dilaurate for catalysis, and react for 3 h; add glacial acetic acid and neutralize the reaction for 0.5 h, add an appropriate amount of deionized water for emulsification for 3 h, and finally heat up to 50 - 60 °C and distill off acetone under reduced pressure to obtain waterborne polyurethane.

[0051] Stir 30 g of the above-mentioned waterborne polyurethane, 2.5 g of mineral oil, 8 g of KH550 coupling agent and 900 g of deionized water at 65 °C for 2 - 3 h to obtain a polyurethane sizing agent.

[0052] Comparative Example 2:

[0053] Add 12μΛ polypropylene glycol and 2μΛ 1,4-butanediol to a three-necked flask, heat to 100-110°C, evacuate three times, and heat for 1η; after evacuating, introduce nitrogen, cool to 70-80°C, add 12μλ isophorone diisocyanate, add three times within 1η, and heat at a constant temperature for 3η; cool to 40°C, add an appropriate amount of anhydrous acetone to reduce the viscosity, then add 1μΛ N-methyldiethanolamine and 1μΛ dibutyltin dilaurate as catalyst, and react for 3η; add glacial acetic acid, neutralize for 0.5η, add an appropriate amount of deionized water for emulsification for 3η, and finally heat to 50-60°C to distill acetone under reduced pressure to obtain waterborne polyurethane.

[0054] The above-mentioned aqueous polyurethane 30γ, mineral oil 25γ, KH550 coupling agent 8γ, and deionized water 900γ were stirred at 65° C. for 2 to 3η to obtain a wetting agent.

[0055] The performance test was conducted on the sizing-treated basalt fibers prepared in the examples and comparative examples, that is, elastic basalt fibers were obtained by in-situ polymerization at a temperature of 110-150°C.

[0056] The method for testing the breaking strength performance of basalt fiber treated with sizing agent is in accordance with FB / T7690-2013 "Test Method for Reinforcement Material Yarn". The test results and data are compared in Table 1. Figure 1 , Figure 2 and Figure 3 shown.

[0057] The test method of fiber elasticity adopts the single fiber natural minimum circle diameter measurement method. Take a single fiber with a length of about 40μμ, clamp the two ends of the fiber with tweezers, bend it into a circle, measure the minimum circle diameter when the fiber breaks, and when the fiber breaks, take a picture of the diameter of the knotted fiber to evaluate the fiber elasticity parameters. The smaller the diameter of the knotted fiber, the better the elasticity of the basalt fiber.

[0058] Table 1 Performance measurement values ​​of sizing agent and basalt fiber in various embodiments

[0059]

Claims

1. A long-lasting and stable aqueous sizing agent for preparing elastic basalt fiber, characterized in that: The invention is prepared by stirring the following: 2-4% of blocked polyurethane, 2-4% of epoxy resin, 0.3-0.8% of coupling agent, 0.2-0.8% of lubricant and the balance of deionized water; wherein the blocked polyurethane is prepared from deionized water, blocking agent, accelerator and the following components in mass fraction: 40-50% of polyether polyol, 4-8% of small molecule alcohol, 30-40% of diisocyanate, 2-6% of chain extender and 2-6% of catalyst.

2. The long-lasting and stable aqueous sizing agent for preparing elastic basalt fiber according to claim 1, characterized in that: The preparation method of the blocked polyurethane is: ∑1, by mass fraction, 40-50% of polyether polyol and 4-8% of small molecule alcohol are mixed at 100-110° C. to obtain a mixture; ∑2, by mass fraction, 30-40% of diisocyanate is mixed with the product obtained in ∑1, and the reaction time is 2-3η at 70-90°C; ∑3, by mass fraction, 2-6% of a chain extender and 2-6% of a catalyst are added dropwise to the system obtained in ∑2, the reaction temperature is 40-50°C, the reaction time is 0.5-1η, and a polyurethane prepolymer is obtained; ∑4 reacting the end-capping agent and the accelerator with the prepolymer in ∑3, the end-capping time is 0.5 to 1η, the end-capping temperature is 20° C., and a end-capped polyurethane prepolymer is obtained; ∑5: Mix deionized water and the prepolymer obtained in ∑4 at a ratio of 1:10, emulsify, and stir for 1 to 3η to obtain a blocked polyurethane.

3. The long-lasting stable aqueous sizing agent for preparing elastic basalt fiber according to claim 2, characterized in that: The following steps are involved: ∑1 In terms of mass fraction, 2-4% of blocked polyurethane, 0.3-0.8% of coupling agent and 0.2-0.8% of lubricant are stirred for 2-3η, the reaction temperature is 65°C, and finally 2-4% of epoxy resin is added to obtain a blocked polyurethane and epoxy resin composite basalt fiber impregnating agent; ∑2 The basalt fiber is in-situ impregnated with the impregnating agent in ∑1, and the temperature at the fiber outlet position is 110-150°X, and the impregnating agent is applied to achieve basalt continuous fiber coating.

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