Water-based crosslinking agents, water-based adhesives, functional processing agents, resin coatings, functional fiber structures, and methods for manufacturing functional fiber structures.

Abstract

The present invention provides a water-based crosslinking agent that exhibits excellent reactivity at relatively low temperatures and reduces environmental impact, as well as water-based adhesives, functional processing agents, resin coatings, functional fiber structures, and methods for manufacturing functional fiber structures using the same. [Solution] The aqueous crosslinking agent comprises a cyanate ester compound containing at least one compound selected from the group consisting of the compound represented by the following formula (1) and the compound represented by the following formula (2), a surfactant, and a dispersion medium containing water. [Formula 1] TIFF2026142037000027.tif25158 [C2] TIFF2026142037000028.tif22159

Description

Technical Field

[0001] The present disclosure relates to an aqueous crosslinking agent, an aqueous adhesive, a functional processing agent, a resin coating, a functional fiber structure, and a method for producing a functional fiber structure.

Background Art

[0002] When attaching functional materials such as flame retardants and antibacterial agents to fiber structures, thermoplastic resins are generally used as adhesives. By processing a fiber structure via a padding method or a coating method using a processing liquid containing a functional material having a desired function and a thermoplastic resin, the functional material can be attached to the fiber structure using the thermoplastic resin as an adhesive.

[0003] For such processing, from the viewpoints of reducing environmental load, improving working environment and safety, etc., it is preferable to use water as a solvent instead of Volatile Organic Compounds. However, aqueous thermoplastic resins that generally use water as a solvent have weaker adhesion to functional materials and fiber structures than solvent-based thermoplastic resins that use volatile organic compounds as solvents. For this reason, solvent-based thermoplastic resins tend to continue to be used for such processing in fields where durability is required.

[0004] A technique is known in which a crosslinking agent is added to a processing solution to improve the adhesion of water-based thermoplastic resins to functional materials and fibrous structures. This agent is crosslinked by heating during processing, and the crosslinked resin firmly adheres the functional material to the fibrous structure. Compounds having isocyanate groups, such as toluene diisocyanate and hexamethylene diisocyanate, are used as crosslinking agents. However, these compounds cannot be dispersed or emulsified in water as they are due to the high reactivity of the isocyanate group with water. For this reason, blocked isocyanates, in which the isocyanate group is blocked by a blocking agent such as an oxime compound, a caprolactam compound, or a pyrazole compound, are used for water-based isocyanate compounds. Patent Document 1 discloses a water-based crosslinking agent in which such a crosslinking agent is dispersed in water.

[0005] Such water-based crosslinking agents are used not only in processing fibrous structures to impart functional materials, but also in paints, adhesives, coatings, and foaming agents. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2011-208050 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] When processing fibrous structures by adding an aqueous crosslinking agent to a processing solution containing an aqueous thermoplastic resin, heating the processing solution to a predetermined temperature dissociates the blocking agent from the blocked isocyanate, causing a crosslinking reaction between the isocyanate group and the thermoplastic resin. However, the dissociated organic compound, the blocking agent, is released into the atmosphere. Therefore, despite being an aqueous crosslinking agent, it poses an environmental challenge.

[0008] Furthermore, heating the processing solution to a predetermined temperature is necessary to dissociate the blocking agent, and the energy consumption due to heating becomes a challenge. On the other hand, if the heating temperature is lowered, the crosslinking reaction with the thermoplastic resin becomes insufficient, resulting in a deterioration of the water resistance of the resulting resin coating, leading to problems such as reduced adhesive strength and devitrification of the coating. In applications where adhesive strength and the appearance of the resin coating are important, it is required that these properties change as little as possible.

[0009] To address these challenges, there is a need for a water-based crosslinking agent that exhibits good reactivity with thermoplastic resins even at low heat treatment temperatures. This disclosure aims to provide a water-based crosslinking agent that exhibits excellent reactivity at relatively low temperatures and reduces environmental impact, as well as a water-based adhesive, a functional processing agent, a resin coating, a functional fiber structure, and a method for manufacturing a functional fiber structure using the same. [Means for solving the problem]

[0010] An aqueous crosslinking agent according to one embodiment of the present disclosure comprises a cyanate ester compound comprising at least one compound selected from the group consisting of a compound represented by the following formula (1) and a compound represented by the following formula (2), a surfactant, and a dispersion medium containing water. [ka] [ka] [Effects of the Invention]

[0011] According to one embodiment of the present disclosure, a water-based crosslinking agent exhibiting excellent reactivity at relatively low temperatures and reducing environmental impact is provided, as well as a water-based adhesive, a functional processing agent, a resin coating, a functional fiber structure, and a method for manufacturing a functional fiber structure using the same. [Modes for carrying out the invention]

[0012] (First Embodiment) Embodiments of an aqueous crosslinking agent are described. The aqueous crosslinking agent of the present embodiment includes: a cyanate ester compound containing at least one selected from the group consisting of a compound represented by the following formula (1) and a compound represented by the following formula (2); a surfactant; and a dispersion medium containing water.

Chemical Formula

Chemical Formula

[0013] The compound represented by formula (1) is bisphenol A dicyanate, and the compound represented by formula (2) is bisphenol E dicyanate. The compound represented by formula (1) and the compound represented by formula (2) are commercially available. Hereinafter, the compound represented by formula (1) is referred to as compound 1, and the compound represented by formula (2) is referred to as compound 2.

[0014] Alternatively, compound 1 and compound 2 may be synthesized from appropriate starting materials. For example, compound 1 or compound 2 may be synthesized by a method in which bisphenol A or bisphenol E is prepared, reacted with cyanogen halide in the presence of a tertiary amine.

[0015] Compound 1 and compound 2 are each a cyanate ester compound having cyanate groups at both terminals. When compound 1 or compound 2 is heated, one or two of the C-N triple bonds at both terminals are cleaved, and addition polymerization can proceed. At this time, the presence of a thermoplastic resin described later causes reaction with the functional groups in the thermoplastic resin and addition polymerization with the thermoplastic resin. Thereby, the crosslinking reaction of the thermoplastic resin proceeds. A reaction in which compound 1 and / or compound 2 undergo addition polymerization with each other to form a polymer may occur simultaneously. Compound 1 and compound 2 initiate addition polymerization at about 100°C. This temperature is lower than the addition polymerization initiation temperature of known aqueous crosslinking agents containing blocked isocyanate compounds.

[0016] Compound 1 is solid at ordinary temperature, and Compound 2 is liquid at ordinary temperature. The cyanate ester compound is in the form of particles or droplets and is dispersed or emulsified in a dispersion medium. The average particle diameter of the cyanate ester compound is preferably 40 µm or less. Generally, the particle diameter of the crosslinking agent affects the water resistance of the formed thermoplastic resin coating, and the smaller the particle diameter is, the higher water resistance can be imparted to the thermoplastic resin coating.

[0017] The dispersion medium contains water. In addition to water, an organic solvent such as alcohol may further be contained. Examples of the organic solvent include ketones such as acetone and methyl ethyl ketone; alcohols such as methyl alcohol and ethyl alcohol; glycols such as ethylene glycol and propylene glycol; ethers such as dioxane; alkylene glycol alkyl ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether and ethylene glycol monoisobutyl ether; amides such as dimethylformamide; sulfoxides such as dimethyl sulfoxide; and halogenated hydrocarbons such as methylene chloride and chloroform. These organic solvents may be mixed with water alone, or two or more kinds thereof may be combined and mixed with water as needed.

[0018] The surfactant comprises at least one selected from the group consisting of nonionic surfactants and anionic surfactants. The surfactant may comprise two or more nonionic surfactants and / or anionic surfactants.

[0019] Examples of nonionic surfactants include polyoxyalkylene-type nonionic surfactants such as higher alcohol alkylene oxide adducts, alkylphenol alkylene oxide adducts, fatty acid alkylene oxide adducts, polyhydric alcohol aliphatic ester alkylene oxide adducts, higher alkylamine alkylene oxide adducts, fatty acid amide alkylene oxide adducts, polyoxyalkylene styrene phenyl ethers, and polyoxyalkylene benzylphenyl ethers, as well as polyhydric alcohol-type nonionic surfactants such as alkyl glycosides and sucrose fatty acid esters. Among these, polyoxyalkylene styrene phenyl ethers and polyoxyalkylene benzylphenyl ethers are more preferred.

[0020] Examples of anionic surfactants include sulfate salts such as higher alcohol sulfate salts, higher alkyl ether sulfate salts, sulfated fatty acid ester salts, sulfate salts of styrene-phenol alkylene oxide adducts, phosphate salts such as phosphate salts of styrene-phenol alkylene oxide adducts, alkylbenzene sulfonates, alkylnaphthalene sulfonates, sulfonates such as salts of bis(styrene-phenyl ether alkylene oxide adduct) succinate ester sulfonates, higher alcohol phosphate salts, phosphate salts of alkylene oxide adducts of higher alcohols, alkali metal salts of hydrolysates of diisobutylene-maleic anhydride copolymers, and ammonia. Examples include alkali metal salts and ammonium salts of diisobutylene-maleic anhydride half-esterified products (where the ester in the half-ester is an alkyl ester having 1 to 8 carbon atoms or an alkoxyethyl ester having 1 to 8 carbon atoms of an alkoxy group), alkali metal salts and ammonium salts of hydrolysates of styrene-maleic anhydride copolymers, alkali metal salts and ammonium salts of styrene-maleic anhydride half-esterified products (where the ester in the half-ester is an alkyl ester having 1 to 8 carbon atoms or an alkoxyethyl ester having 1 to 8 carbon atoms of an alkoxy group), and alkali metal salts and ammonium salts of diisobutylene-(meth)acrylic acid copolymers. Among these, sulfate ester salts of styrene-phenol alkylene oxide adducts and salts of bis(styrene-phenyl ether alkylene oxide adduct) succinate ester sulfonates are more preferred.

[0021] The amount of cyanate ester compound added is, for example, 20 parts by weight or more and 100 parts by weight or less per 100 parts by weight of the dispersion medium. The amount of surfactant added is, for example, 1 part by weight or more and 5 parts by weight or less per 100 parts by weight of the cyanate ester compound.

[0022] The aqueous crosslinking agent of this embodiment may contain other materials as needed. For example, to improve the storage stability of the aqueous crosslinking agent, it may contain protective colloidal agents such as polyvinyl alcohol, methylcellulose, carboxymethylcellulose, and starch paste, as well as preservatives. Furthermore, to improve lightfastness, the aqueous crosslinking agent may contain ultraviolet absorbers and antioxidants. The aqueous crosslinking agent may contain one or more of these materials.

[0023] The aqueous crosslinking agent of this embodiment is obtained by mixing a dispersion medium with the materials described above. Specifically, when the aqueous crosslinking agent contains compound 1, compound 1 and a surfactant are weighed, these materials are added to the dispersion medium, and then compound 1 is pulverized using a wet pulverizer to obtain an aqueous crosslinking agent in which compound 1 is dispersed in a solvent.

[0024] If the aqueous crosslinking agent contains compound 2, weigh compound 2 and the surfactant, mix them, and heat the mixture while stirring. Pour the weighed dispersion medium into a separate container and heat the dispersion medium. Gradually add the dispersion medium dropwise to the heated mixture to obtain an aqueous crosslinking agent in which compound 2 is emulsified. As an emulsifying device, a stirrer, homogenizer, homomixer, high-pressure emulsifier, etc., can be used.

[0025] If the aqueous crosslinking agent contains compound 1 and compound 2, an aqueous crosslinking agent containing compound 1 and an aqueous crosslinking agent containing compound 2, prepared by the method described above, can be weighed and mixed so that the content of compound 1 and compound 2 is in a desired ratio, thereby obtaining an aqueous crosslinking agent containing compound 1 and compound 2.

[0026] The aqueous crosslinking agent of this embodiment is suitably used as a crosslinking agent for aqueous resins. Specifically, it is used in combination with aqueous resins in various applications such as paints, films, sheets, coatings for metals, paper, leather, etc., adhesives for various applications, binders for fibrous materials such as paper, fibers, nonwoven fabrics, and glass, and functional processing agents for fibers.

[0027] In any application, according to this embodiment, by heating to 100°C or higher, which is a lower temperature than conventional methods, an addition reaction occurs between the aqueous resin and the cyanate ester compound in the aqueous crosslinking agent, resulting in the crosslinking of the aqueous resin. Compared to conventionally used blocked isocyanates, it exhibits good reactivity with thermoplastic resins even at lower heat treatment temperatures, and offers excellent convenience with a wide range of temperature settings.

[0028] Furthermore, in compounds 1 and 2, organic compounds such as the blocking agent for blocked isocyanates do not dissociate and are not released into the atmosphere during the crosslinking reaction. Therefore, the environmental burden is reduced.

[0029] (Second Embodiment) An embodiment of a water-based adhesive will now be described. The water-based adhesive of this embodiment comprises a water-based crosslinking agent of the first embodiment and a thermoplastic resin. The thermoplastic resin preferably contains a functional group that exhibits a crosslinking reaction with a cyanate ester compound. Specifically, the thermoplastic resin contains at least one functional group selected from the group consisting of hydroxyl groups, amino groups, carboxyl groups, thiol groups, epoxy groups, and maleimide groups.

[0030] The thermoplastic resin preferably includes at least one selected from the group consisting of ether-based urethane resins, polyester resins, and nylon resins. Examples of ether-based urethane resins include "HYDLAN HW-312B," "HYDLAN WLS-201," "HYDLAN WLS-202," and "BONDIC 1310NE" from DIC Corporation; "Superflex 130," "Superflex 870," and "Superflex E-4800" from Daiichi Kogyo Seiyaku Co., Ltd.; "ADEKA BONTITER HUX-320," "ADEKA BONTITER HUX-550," "ADEKA BONTITER HUX-950," and "ADEKA BONTITER HUX-282" from ADEKA Corporation; "EDOLAN SN" and "EDOLAN SC" from Tanatex Chemicals Japan Co., Ltd.; "Permarin UA-190" from Sanyo Chemical Industries, Ltd.; and "Rezamin D-2040," "Rezamin D-1063," "Rezamin D-4080," and "Rezamin D-4200" from Dainichi Seika Kogyo Co., Ltd. Examples of polyester resins include "Pluscoat Z-730" and "Pluscoat Z-760" manufactured by Go-o Chemical Industry Co., Ltd. Examples of nylon resins include "Seporjon PA150" and "Seporjon PA200" manufactured by Sumitomo Seika Co., Ltd.

[0031] In the water-based adhesive of this embodiment, the ratio of the cyanate ester compound to the thermoplastic resin can be determined according to the type of cyanate ester compound and thermoplastic resin selected, the shape, material, constituent elements, application, required bonding strength, water resistance, etc. For example, the adhesive of this embodiment may contain the cyanate ester compound in a ratio of 1 part by weight to 1400 parts by weight per 100 parts by weight of the thermoplastic resin. Preferably, the adhesive contains the cyanate ester compound in a ratio of 10 parts by weight to 500 parts by weight per 100 parts by weight of the thermoplastic resin, and more preferably, it contains the cyanate ester compound in a ratio of 50 parts by weight to 400 parts by weight per 100 parts by weight of the thermoplastic resin.

[0032] If the proportion of the cyanate ester compound to the thermoplastic resin is less than 1 part by weight, a sufficient cross-linking structure will not be formed in the thermoplastic resin, and the water-based adhesive will not be able to exhibit high water resistance. Similarly, if the proportion of the cyanate ester compound exceeds 1400 parts by weight, the amount of thermoplastic resin that performs the adhesive function will be relatively small, and therefore the water-based adhesive will not be able to exhibit high water resistance.

[0033] Thermoplastic resins are either dissolved in water or emulsified in droplet form in the dispersion medium of water-based adhesives. The average particle size of the thermoplastic resin is, for example, between 0.05 μm and 10.0 μm. Similar to cyanate ester compounds in water-based crosslinking agents, generally, the smaller the particle size of the thermoplastic resin, the higher the bonding strength as an adhesive tends to be.

[0034] The water-based adhesive of this embodiment is obtained by weighing and mixing the water-based crosslinking agent described in the first embodiment and a thermoplastic resin, respectively.

[0035] Next, the method of using the water-based adhesive of this embodiment will be described. First, the water-based adhesive of this embodiment is applied to or added to an object, and then the dispersion medium is evaporated from the object containing the water-based adhesive by heating. The heating may be performed at a temperature of less than 100°C or 100°C or higher.

[0036] Furthermore, by holding the object at a temperature of 100°C or higher, some of the triple bonds of the cyanate ester compound are cleaved and react with the aforementioned functional groups in the thermoplastic resin. The temperature at which the object is held is preferably between 100°C and 200°C. As a result, at least some of the terminal cyanate groups bond to the thermoplastic resin by addition polymerization, forming a crosslinked structure of the cyanate ester compound in the thermoplastic resin, and creating a resin coating made of a thermosetting resin having a three-dimensional network structure.

[0037] When using materials such as films, sheets, metals, paper, and leather as the target material, applying the resin coating to the surface of these materials results in a resin coating that is firmly bonded to the material, and the surface of the material is covered with the resin coating. In this case, the water-based adhesive is a coating agent. The form of the resin coating will be described in detail below. Furthermore, when the target material is a fibrous material such as paper, fiber, nonwoven fabric, or glass, and the water-based adhesive is added to the target material, a fibrous material with the resin coating as a binder is obtained. When a large amount of resin coating is added, it is also called a composite material. In addition, when the water-based adhesive further contains a functional material as the target material, the water-based adhesive is a functional processing agent. Examples of functional processing agents will be described in detail below.

[0038] As described in the first embodiment, the water-based adhesive of this embodiment exhibits good reactivity with thermoplastic resins even at low heat treatment temperatures compared to blocked isocyanates, and offers excellent convenience due to its wide temperature range. Furthermore, since no organic compounds such as blocking agents dissociate during the crosslinking reaction, the environmental burden is reduced.

[0039] (Third embodiment) Embodiments of resin coatings and resin-coated fiber structures will be described. The resin coating of this embodiment comprises a main chain derived from a thermoplastic resin and a crosslinked structure derived from a cyanate ester compound, which includes at least one compound selected from the group consisting of compound 1 and compound 2 described in the first and second embodiments. As described in the second embodiment, at least a portion of the cyanate groups at the ends of the cyanate ester compound are bonded to the functional groups of the thermoplastic resin by addition polymerization, forming a crosslinked structure. Due to the crosslinked structure, the resin coating constitutes a thermosetting resin having a three-dimensional network structure.

[0040] The resin-coated fiber structure of this embodiment includes a fiber structure and a resin coating fixed to the fiber structure. The resin coating provides the fiber structure with waterproofing, stain resistance, and other properties.

[0041] The ratio of the resin coating to the fiber structure can be arbitrarily selected depending on the type of fiber, mesh structure, and application of the fiber structure. For example, the ratio of the resin coating to the fiber structure is 10 wt% to 30 wt% (owf). If the ratio of the resin coating is less than 10 wt%, it may not be possible to adequately impart the above-mentioned functions such as waterproofing to the fiber structure. If the ratio of the resin coating exceeds 30 wt%, the texture of the fiber structure may be significantly deteriorated. However, when implementing a resin-coated fiber structure as a composite material of a resin coating and a fiber structure, the resin coating may be fixed at a ratio exceeding the above-mentioned upper limit.

[0042] Examples of fiber structures that can be used in this embodiment include chemical fibers such as synthetic fibers, semi-synthetic fibers, regenerated fibers, and inorganic fibers, as well as natural fibers such as plant fibers and animal fibers. More specifically, examples of synthetic fibers include polyester fibers, nylon fibers, vinylon fibers, acrylic fibers, polyethylene fibers, polypropylene fibers, polyurethane fibers, and polylactic acid fibers; examples of semi-synthetic fibers include acetate fibers; examples of regenerated fibers include rayon fibers, viscose rayon fibers, cupro fibers, and lyocell fibers; and examples of inorganic fibers include glass fibers and carbon fibers.

[0043] Examples of resin-coated fiber structures include, for example, seat cushions, seat covers, curtains, wallpaper, ceiling coverings, carpets, stage curtains, construction protective sheets, tents, and canvas.

[0044] The resin coating and resin-coated fiber structure of this embodiment are obtained by processing the fiber structure with the water-based adhesive described in the second embodiment, drying, and then heating. There are no particular restrictions on the processing method; for example, the water-based adhesive can be applied to the fiber structure by padding, spraying, coating, printing, screen printing, etc. It is preferable to apply the water-based adhesive to the fiber structure in the range of the above-mentioned proportions, calculated based on the total weight of the thermoplastic resin and the cyanate ester compound.

[0045] By drying, that is, after evaporating the dispersion medium, the thermoplastic resin is heat-treated at a temperature between 100°C and 200°C to soften it and fix it to the fibers of the fibrous structure, thereby inducing a crosslinking reaction between the cyanate ester compound and the thermoplastic resin. This allows a resin coating consisting of a thermosetting resin having a three-dimensional network structure formed by a main chain derived from the thermoplastic resin and a crosslinked structure derived from the cyanate ester compound to be fixed to the fibrous structure.

[0046] When processing a water-based adhesive using the padding method, the fibrous structure is immersed in the water-based adhesive of the second embodiment, and the fibrous structure containing the water-based adhesive is squeezed with a mangle or the like to achieve the above-mentioned adhesion amount. Then, by heating it for several seconds to several minutes at a temperature in the range of 100°C to 200°C, for example, the dispersion medium is evaporated and the cyanate ester compound is fixed to the fibrous structure using a thermoplastic resin as a binder.

[0047] When processing a water-based adhesive using a coating method, the water-based adhesive of the second embodiment is applied to one or both sides of a fiber structure using a coating device such as a rotary screen, knife roll coater, gravure roll coater, kiss roll coater, or calender coater. Then, the dispersion medium is evaporated and the cyanate ester compound is fixed to the fiber structure using a thermoplastic resin as a binder by heating at a temperature in the range of 100°C to 200°C for several seconds to several minutes.

[0048] According to this embodiment, by heat treatment at a temperature of approximately 100°C or higher, which is lower than conventional methods, a resin coating capable of imparting functions such as waterproofing and stain resistance to the target object can be formed. Therefore, the heat treatment temperature applied to the target object can be kept lower than conventional methods. When the target object is a fibrous structure, the effects of heat treatment on the fibrous structure can be suppressed, and functions such as waterproofing and stain resistance can be imparted while maintaining the various physical properties of the fibrous structure. In addition, since organic compounds such as blocking agents do not dissociate during the crosslinking reaction, the environmental burden is reduced.

[0049] (Fourth Embodiment) Embodiments of functional processing agents and functional fiber structures will be described. The functional processing agent of this embodiment comprises a functional material and a water-based adhesive described in the second embodiment. The functional material is dispersed in the dispersion medium of the water-based adhesive.

[0050] The functional material includes at least one selected from the group consisting of flame retardants, water repellents, antistatic agents, antibacterial agents, and antifungal agents. These functional materials are dispersed or emulsified in the dispersion medium of the water-based adhesive in the form of particles or droplets, or dissolved in the dispersion medium. The average particle size of the functional material is, for example, 0.1 μm to 10.0 μm. Similar to cyanate ester compounds in water-based crosslinking agents, generally, the smaller the particle size of the functional material, the greater the effect it provides.

[0051] For example, flame retardants include phosphorus-based flame retardants, halogen-based flame retardants, nitrogen-based flame retardants, inorganic flame retardants, sulfur-based flame retardants, and the like.

[0052] The functional processing agent of this embodiment is obtained by weighing and mixing a functional material and the water-based adhesive described in the second embodiment.

[0053] The functional fiber structure of this embodiment comprises a functional material, a resin coating as described in the third embodiment, and a fiber structure. The functional material is fixed to the fiber structure by the resin coating. As the fiber structure, the fiber structure described in the third embodiment can be used.

[0054] The functional fiber structure of this embodiment can be manufactured by the following procedure.

[0055] First, a functional material, a thermoplastic resin, and a cyanate ester compound containing at least one selected from the group consisting of compound 1 and compound 2 are supported on the fiber structure. This can be done by applying the above-mentioned functional processing agent to the fiber structure using the processing method described in the third embodiment.

[0056] Next, the processed fiber structure is heat-treated. Specifically, the processed fiber structure is held at a heat treatment temperature of 100°C to 200°C, the dispersion medium is evaporated as needed, and then the thermoplastic resin and the cyanate ester compound are reacted by a crosslinking reaction, thereby bonding the functional material to the fiber structure with the resin film, which is the reaction product.

[0057] According to this embodiment, it is possible to firmly fix functional materials to fiber structures at temperatures of approximately 100°C or higher, which is lower than conventional methods. Therefore, the heat treatment temperature subjected to the fiber structure and functional materials can be kept lower than conventional methods, thereby expanding the range of usable fiber structures and functional materials. In addition, since organic compounds such as blocking agents do not dissociate during the crosslinking reaction, the environmental burden is reduced.

[0058] The method for manufacturing the functional fiber structure in this embodiment may be performed before or after processing using other functional processing agents. [Example 1] To confirm the effects of the first to fourth embodiments, resin-coated fiber structures were prepared from sample 1 to sample 48, and their properties were evaluated.

[0059] 1. Sample preparation (1) Preparation of aqueous crosslinking agents We prepared the cyanate ester compounds shown in Tables A and B (manufactured by Mitsubishi Gas Chemical Company, Inc.). We also prepared the carbodiimide compound shown in Table C (formula (3) below) (manufactured by Lanxess Corporation), and the blocked isocyanate compounds shown in Tables D and E (formulas (4) and (5) below) (manufactured by Meisei Chemical Industry Co., Ltd.). [Table 1] [ka] [ka] [ka]

[0060] Preparation of aqueous crosslinking agent A 40 parts by weight of crystalline bisphenol A dicyanate powder, 1.5 parts by weight of polyoxyethylene tribenzylphenyl ether, and 0.005 parts by weight of a silicone-based defoamer were added to 30 parts by weight of water. The mixture was then homogenized using a homogenizer at a rotation speed of 3,000 rpm for 1 hour to obtain a dispersion with an average particle size of 92.659 μm. This dispersion was passed through a bead mill filled with 0.8 mm glass beads to perform a micronization treatment, obtaining a dispersion containing fine particles with an average particle size of 0.596 μm. Water was added to the obtained dispersion to achieve a non-volatile content concentration of 40.0% to obtain an aqueous crosslinking agent A.

[0061] Similarly, aqueous crosslinking agents A with different average particle sizes were prepared so that their non-volatile content concentration was 40.0%. The prepared aqueous crosslinking agents were used in samples 11 to 14, respectively, and the effect of particle size on the washing durability of the resin coating was investigated.

[0062] Preparation of aqueous crosslinking agent B 20 parts by weight of a pale yellow liquid bisphenol E dicyanate and 0.15 parts by weight of the ammonium salt of the sulfate ester of tristyrenated phenol ethylene oxide adduct were mixed and heated to 80°C under propeller stirring. 74 parts by weight of 80°C hot water were gradually added dropwise to obtain an aqueous crosslinking agent B in which bisphenol E dicyanate was emulsified. The average particle size was 0.777 μm and the non-volatile content concentration was 20.0%.

[0063] Preparation of aqueous crosslinking agent C Thirty parts by weight of bis(diisopropylphenyl)carbodiimide crystalline powder, 1.5 parts by weight of polyoxyethylene distyrenated phenyl ether, and 1.5 parts by weight of the ammonium salt of the sulfate ester of tristyrenated phenol ethylene oxide adduct were mixed, heated to 75°C, and homogenized while dropping 70 parts by weight of 80°C water to obtain an emulsified aqueous crosslinking agent C. The average particle size was 0.073 μm, and the non-volatile content was 24.0%. The average particle size of the aqueous crosslinking agent was measured using a laser diffraction particle size distribution analyzer (SALD-2200, Shimadzu Corporation). (2) Preparation of water-based adhesives, adhesives, or functional processing agents for samples 1 to 48 We prepared the aqueous thermoplastic resins shown in No. 1, 2, 5, and 6 of Table 2, and the cyanate ester compounds shown in A and B of Table 1. [Table 2]

[0064] Thermoplastic resins No. 1 to No. 6 and water-based crosslinking agents A to E were weighed in the proportions shown in Tables 3 to 5 to prepare adhesives for samples 1 to 44. Specifically, thermoplastic resins No. 1, 5, and 6 and water-based crosslinking agents A to E were used, and the various raw materials were mixed so that the solid content ratio of the thermoplastic resin to the water-based crosslinking agent was as shown in Tables 3 to 5. The mixtures were then thickened using "SN Thickener 623N" manufactured by Sunopco Co., Ltd. as a thickening agent to obtain water-based adhesives for samples 5 to 32, samples 34 to 38, and samples 40 to 44.

[0065] As a highly water-resistant water-based urethane resin, "Superflex 470" manufactured by Daiichi Kogyo Seiyaku Co., Ltd. (shown as No. 2 in Table 2) was used, and as a highly water-resistant solvent-based urethane resin, "Crisbon 5816EL" and "Crisbon NY-331" manufactured by DIC Corporation (shown as Nos. 3 and 4) were used. Adhesives for samples 2 to 4 were obtained without the addition of a water-based crosslinking agent.

[0066] Water-based adhesives were obtained for samples 1, 33, and 39, without adding a water-based crosslinking agent to the thermoplastic resins shown in Nos. 1, 5, and 6.

[0067] To verify the effectiveness of the functional processing agent, 100 parts by weight of a dispersion of ethylene bispentabromobenzene (solid content concentration 78%) as a brominated flame retardant was mixed with 83.5 parts by weight of HYDLAN HW-312B, listed as No. 1 in Table 1, as a thermoplastic resin. Two samples were prepared: one without the addition of a water-based crosslinking agent, and another with the addition of water-based crosslinking agents A, C, and E, with a solid content ratio of thermoplastic resin to crosslinking agent of 1:0.2. These samples were designated as samples 45, 46, 47, and 48. (3) Preparation of resin-coated fiber structures or functional fiber structures of Samples 1 to 48 Polyester petromat (weight 160g / m²) 2 A resin-coated fiber structure (polyester fiber fabric) was obtained by preparing the following materials, applying the coating adhesive using a knife coat method, and drying for 5 minutes at each of the temperatures shown in Tables 3 to 5.

[0068] 2. Evaluation The washing durability of the resin coating was evaluated using the resin-coated fiber structures or functional fiber structures prepared from Sample 1 to Sample 48. Specifically, in accordance with JIS K 3371, a weakly alkaline Class 1 detergent was used at a ratio of 1 g / L, and the samples were washed for 15 minutes at a bath ratio of 1:40 and a liquid temperature of 60.0 ± 2.0°C. This was followed by three 5-minute rinses at 40.0 ± 2.0°C, centrifugal dehydration for 2 minutes, and drying at a temperature of 60.0 ± 5.0°C. This constituted one cycle, and a total of five cycles were performed. The weight loss rate was measured from the weight change of the prepared polyester fabric before and after washing. A weight loss rate of less than 50% was considered a pass, and a weight loss rate of 50% or more was considered a fail. In Tables 3 to 5, samples judged to be pass are indicated by P, and samples judged to be failing are indicated by F. [Table 3] [Table 4] [Table 5]

[0069] 3. Results and Discussion Sample 1 uses a water-based polyether-based urethane resin as the thermoplastic resin. Because the water-based adhesive does not contain cyanate ester compounds, the resin coating is almost completely removed by washing, resulting in a large weight loss.

[0070] Sample 2 uses a water-based polycarbonate urethane resin as the thermoplastic resin. Although it does not contain cyanate ester compounds, it exhibits excellent wash durability. However, polycarbonate urethane resins are generally more expensive than polyester urethane resins or polyether urethane resins.

[0071] Samples 3 and 4 use solvent-based urethane resin as the thermoplastic resin. Solvent-based urethane resin has the advantage of superior water resistance compared to water-based urethane resin and exhibits excellent wash durability. However, because the adhesive contains organic solvents as a solvent, VOCs are generated during the drying process, which can lead to a significant environmental burden.

[0072] As shown in Samples 5 to 20, it was found that using cyanate ester compounds, the main components of water-based crosslinking agents A and B, improves the wash durability of ether-based urethane resin (thermoplastic resin No. 1). Generally, the higher the drying temperature, the greater the reactivity between the thermoplastic resin and the crosslinking agent, making it easier to form a network structure. However, even at a drying temperature of 100°C, cyanate ester compounds react with the thermoplastic resin, promoting the formation of a network structure and thus exhibiting high wash durability.

[0073] From the weight loss rates of samples 9, 10, 15, and 16, it can be seen that when the cyanate ester compound is 0.5 parts by weight or less, or exceeds 1400 parts by weight, relative to 100 parts by weight of thermoplastic resin, sufficient adhesive strength cannot be obtained and washing durability decreases. This is thought to be because a thermosetting resin with an appropriate network structure could not be formed when the amount of cyanate ester compound was too little or too much relative to the thermoplastic resin.

[0074] Samples 21 to 24, which used carbodiimide-based crosslinking agents, could not be given sufficient wash durability at drying temperatures below 160°C. Samples 25 to 32, which used blocked isocyanate-based crosslinking agents, required drying temperatures of 140°C or higher, and were found to have poor wash durability at drying temperatures below this level.

[0075] The average particle sizes of samples 11, 12, 13, and 14 were 92.659 μm, 56.945 μm, 32.468 μm, and 17.461 μm, respectively. From the weight loss rates of these samples, it can be seen that it is preferable for the average particle size of the cyanate ester compound to be 40 μm or less. This is thought to be because if the average particle size of the cyanate ester compound is large, an uneven distribution of the cyanate ester compound occurs on the fiber structure during processing, resulting in areas where a sufficient cross-linked structure is not formed in the thermoplastic resin.

[0076] As shown in samples 34, 35, 40, and 41, it was found that even if the thermoplastic resin is nylon resin or polyester resin, a resin coating with high wash durability can be formed by using a cyanate ester compound.

[0077] On the other hand, as shown in samples 37, 38, 43, and 44, it was found that when the thermoplastic resin was nylon or polyester, high wash durability could not be obtained when using isocyanate-based crosslinking agents. Furthermore, as shown in sample 42, it was found that high wash durability could not be obtained for nylon resin when using carbodiimide-based crosslinking agents. These results indicate that cyanate ester compounds can form water-based adhesives that can crosslink a wider range of thermoplastic resins with good crosslinking reactions than compounds used in conventional water-based crosslinking agents.

[0078] As shown in Sample 45, when a functional material is mixed with an ether-based urethane resin (thermoplastic resin No. 1), the wash durability of the resin coating is poor, resulting in a large weight loss rate. As shown in Sample 46, it was found that the wash durability of the resin coating is improved by using a cyanate ester compound. In contrast, as shown in Samples 47 and 48, when blocked isocyanate compounds or carbodiimide compounds are used, the crosslinking reaction is insufficient, and the wash durability is worse compared to when cyanate ester compounds are used.

[0079] Thus, the results from samples 1 to 48 show that the water-based adhesive of this embodiment can form a resin coating with excellent washing durability by heat treatment at a reaction temperature of 100°C or higher. Furthermore, compared to conventionally used blocked isocyanates, it exhibits good reactivity with thermoplastic resins even at lower heat treatment temperatures, and offers superior convenience due to its wide temperature range.

[0080] [Example 2] The results of evaluating the appearance of the resin coatings in the first to fourth embodiments are shown. 1. Preparation of resin coating As the thermoplastic resin, the thermoplastic resin shown as No. 1 in Table 1 (HYDLAN HW-312B) was used, and water-based crosslinking agents A to E were used as crosslinking agents. A water-based adhesive was obtained by mixing the resin and crosslinking agents so that the solid content concentration ratio was 1:0.2. The obtained adhesive was poured into a 3cm x 6cm silicone container and pre-dried at 40°C for 24 hours to obtain a resin film. The obtained resin film was dried at 100°C for 30 minutes to cure. Furthermore, the cured resin film was immersed in room temperature water for 24 hours, and the degree of whitening of the resin film was evaluated. 2. Evaluation The appearance of each resin coating was evaluated after pre-drying, curing, and immersion in room-temperature water. The evaluation was performed visually and by spectrophotometer.

[0081] Visual inspection determined whether the resin coating was transparent or had turned white. The evaluation results are shown in Table 6.

[0082] Using a spectrophotometer CM-600d (manufactured by Konica Minolta, Inc.), the L of the resin coating was measured. * The value of L was measured. * The value is called the lightness index; a larger value indicates brighter light, and a smaller value indicates darker light. The L value of the resin coating after each process. * The L value was measured and used as a reference for a coating made only from thermoplastic resin. * The difference, ΔL, was calculated. Table 7 shows the measured values. A positive ΔL value indicates that the resin coating tends to whiten with the use of a crosslinking agent, and the larger the value, the more severe the whitening. A negative ΔL value indicates that the whitening of the resin coating is reduced with the use of a crosslinking agent. Samples with a ΔL of 15 or higher were judged as unacceptable, and those with a ΔL of less than 15 were judged as acceptable. In Table 7, samples judged as acceptable are indicated by P, and samples judged as unacceptable are indicated by F. [Table 6] [Table 7]

[0083] 3. Results and Discussion As shown in Table 6, visual evaluation revealed that when aqueous crosslinking agent B, a cyanate ester compound, was used, no whitening was observed after curing and after immersion in room temperature water, maintaining good transparency. Furthermore, when aqueous crosslinking agent A was used, the material was transparent after curing. Slight whitening was observed after immersion in room temperature water, but this whitening was reduced compared to the case using thermoplastic resin alone, or when blocked isocyanate crosslinking agents or carbodiimide crosslinking agents were used in combination. On the other hand, when crosslinking agent C, a carbodiimide-based crosslinking agent, was used, whitening was observed at all stages. When crosslinking agents D and E, which are blocked isocyanate-based crosslinking agents, were used, the material was transparent after curing, but whitening was observed after immersion in room temperature water.

[0084] As shown in Table 7, similar results were obtained with evaluation using a spectrophotometer, and the resin coatings using water-based crosslinking agents A and B passed at every stage.

[0085] On the other hand, when crosslinking agent C was used, the sample failed at every stage. When crosslinking agents D and E were used, the sample passed after curing, but failed after immersion in room temperature water.

[0086] These results indicate that the resin coating obtained with the water-based adhesive of this embodiment has excellent transparency in appearance and can maintain excellent transparency even after immersion in water. The resin coating obtained with the water-based adhesive of this embodiment can be suitably used in various applications where adhesion and the appearance of the resin coating are important.

[0087] The aqueous crosslinking agent disclosed herein, and aqueous adhesives, functional processing agents, resin coatings, functional fiber structures, and methods for manufacturing functional fiber structures using the same can also be described as follows.

[0088] The first aqueous crosslinking agent comprises a cyanate ester compound containing at least one compound selected from the group consisting of the compound represented by the following formula (1) and the compound represented by the following formula (2), a surfactant, and a dispersion medium containing water. [ka] [ka]

[0089] In the second configuration, the aqueous crosslinking agent may contain the cyanate ester compound dispersed or emulsified in the dispersion medium.

[0090] The aqueous crosslinking agent relating to the third configuration may include at least one surfactant selected from the group consisting of nonionic surfactants and anionic surfactants in the first configuration.

[0091] In the fourth component, the aqueous crosslinking agent may have an average particle size of 40 μm or less of the cyanate ester compound in the first component.

[0092] The fifth water-based adhesive comprises a water-based crosslinking agent of any one of the first to fourth components and a thermoplastic resin.

[0093] The water-based adhesive relating to the sixth configuration may, in the fifth configuration, include at least one thermoplastic resin selected from the group consisting of ether-based urethane resin, polyester resin, and nylon resin.

[0094] The water-based adhesive relating to the seventh composition may contain, in the sixth composition, the cyanate ester compound in a ratio of 1 part by weight to 1400 parts by weight per 100 parts by weight of the thermoplastic resin.

[0095] The functional processing agent relating to the eighth component includes a functional material and a water-based adhesive relating to the fifth component.

[0096] In the ninth configuration, the functional processing agent may, in the eighth configuration, include at least one selected from the group consisting of flame retardants, water repellents, antistatic agents, antibacterial agents, and antifungal agents.

[0097] The resin coating relating to the tenth configuration comprises a main chain derived from a thermoplastic resin and a crosslinked structure derived from a cyanate ester compound containing at least one compound selected from the group consisting of the compound represented by the following formula (1) and the compound represented by the following formula (2), wherein at least a portion of the terminal cyanate groups are bonded to the main chain by addition polymerization. [ka] [ka]

[0098] The functional fiber structure according to the 11th configuration includes a functional material containing at least one selected from the group consisting of a flame retardant, a water repellent, an antistatic agent, an antifungal agent, and an antifungal agent, a resin coating according to the 10th configuration, and a fiber structure, wherein the functional material is bonded to the fiber structure by the resin coating.

[0099] A method for manufacturing a functional fiber structure relating to the 12th configuration involves supporting a fiber structure with a functional material containing at least one selected from the group consisting of a flame retardant, a water repellent, an antistatic agent, an antifungal agent, and an antifungal agent, a thermoplastic resin, and a cyanate ester compound containing at least one selected from the group consisting of a compound represented by the following formula (1) and a compound represented by the following formula (2), [ka] [ka]

[0100] The fibrous structure is heat-treated to react the thermoplastic resin with the cyanate ester compound, and the functional material is fixed to the fibrous structure by the reaction product.

[0101] In the manufacturing method of the functional fiber structure relating to the 13th configuration, the heat treatment may be performed at a temperature of 100°C or higher in the 12th configuration. [Industrial applicability]

[0102] The aqueous crosslinking agent, aqueous adhesive, functional processing agent, resin coating, functional fiber structure, and method for producing the functional fiber structure disclosed herein are suitably used in various applications using aqueous resins.

Claims

1. An aqueous crosslinking agent comprising a cyanate ester compound containing at least one compound selected from the group consisting of the compound represented by the following formula (1) and the compound represented by the following formula (2), a surfactant, and a dispersion medium containing water. 【Chemistry 1】 【Chemistry 2】

2. The aqueous crosslinking agent according to claim 1, wherein the cyanate ester compound is dispersed or emulsified in the dispersion medium.

3. The aqueous crosslinking agent according to claim 1, wherein the surfactant comprises at least one selected from the group consisting of nonionic surfactants and anionic surfactants.

4. The aqueous crosslinking agent according to claim 1, wherein the average particle size of the cyanate ester compound is 40 μm or less.

5. A water-based adhesive comprising a water-based crosslinking agent according to any one of claims 1 to 4 and a thermoplastic resin.

6. The aqueous adhesive according to claim 5, wherein the thermoplastic resin comprises at least one selected from the group consisting of ether-based urethane resin, polyester resin, and nylon resin.

7. The aqueous adhesive according to claim 5, comprising 1 part by weight or more and 1,400 parts by weight or less of the cyanate ester compound per 100 parts by weight of the thermoplastic resin.

8. A functional processing agent comprising a functional material and the water-based adhesive described in claim 5.

9. The functional processing agent according to claim 8, wherein the functional material comprises at least one selected from the group consisting of flame retardants, water repellents, antistatic agents, antibacterial agents, and antifungal agents.

10. A resin coating comprising a main chain derived from a thermoplastic resin and a crosslinked structure derived from a cyanate ester compound comprising at least one compound selected from the group consisting of the compound represented by the following formula (1) and the compound represented by the following formula (2), wherein at least a portion of the terminal cyanate groups are bonded to the main chain by addition polymerization. 【Chemistry 1】 【Chemistry 2】

11. A functional fiber structure comprising a functional material containing at least one selected from the group consisting of a flame retardant, a water repellent, an antistatic agent, an antimicrobial agent, and an antifungal agent, a resin coating as defined in claim 10, and a fiber structure, wherein the functional material is bonded to the fiber structure by the resin coating.

12. A functional material containing at least one selected from the group consisting of flame retardants, water repellents, antistatic agents, antibacterial agents, and antifungal agents, a thermoplastic resin, and a cyanate ester compound containing at least one selected from the group consisting of compounds represented by the following formula (1) and compounds represented by the following formula (2) are supported on a fibrous structure, 【Chemistry 1】 【Chemistry 2】 A method for producing a functional fiber structure, comprising heat-treating the fiber structure, reacting the thermoplastic resin with the cyanate ester compound, and fixing the functional material to the fiber structure with the reaction product.

13. The method for producing a functional fiber structure according to claim 12, wherein the heat treatment is performed at a temperature of 100°C or higher.

Images