Fiber bundling agent and fiber

Abstract

To provide a fiber bundling agent that allows suppression of crystallization in an aqueous solution state and exhibits superior bundling performance.SOLUTION: A fiber bundling agent includes a vinyl ester resin (A) represented by a chemical formula (1) and a nonionic surfactant (B). In the chemical formula (1), a vinyl ester resin (A1) in which n is 1, a vinyl ester resin (A2) in which n is 2, a vinyl ester resin (A3) in which n is 3, and a vinyl ester resin (A4) in which n is 4 are included. R1 is independently a C1-C3 alkylene group. R2 and R3 are each independently a hydrogen atom or a C1-C4 alkyl group. n is an integer of 0 or more and 20 or less.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a fiber sizing agent and a fiber.

Background Art

[0002] A sizing agent is a chemical applied to fiber materials such as carbon fibers and is used for purposes such as suppressing damage to the fiber material and enhancing the bundling property of the fiber material.

[0003] Patent Document 1 discloses a fiber sizing agent composition containing a vinyl ester resin (A) represented by the following chemical formula (4) and a nonionic surfactant (B), wherein the vinyl ester resin (A) includes at least a vinyl ester resin (A1) in which n in the following chemical formula (4) is 0 or 1 and a vinyl ester resin (A2) in which n in the following chemical formula (4) is 2 or more, and n in the following chemical formula (4) per molecule of the vinyl ester resin (A) is 20 or less, and a fiber sizing agent composition is described in which the ratio (W1 / W2) of the total weight W1 of the vinyl ester resin (A1) in which n in the following chemical formula (4) is 0 or 1 to the total weight W2 of the vinyl ester resin (A2) in which n in the following chemical formula (4) is 2 or more is 15 / 85 to 90 / 10.

Chem.

[0004] In the formula, R 1 is each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, and R 2 is each independently a structural moiety represented by either a methylene group or an isopropylidene group, and R 3 is each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and n is an integer of 0 or more.

[0005] The sizing agent described in Patent Document 1 was excellent in bundling property and also excellent in the adhesiveness between the fiber and the matrix resin.

Prior Art Documents

Patent Document

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] In the sizing agent described in Patent Document 1, when it is in an aqueous solution state, a part of the components of the sizing agent may crystallize. If such crystallization occurs during the storage of the sizing agent, there has been an inconvenience such as it becoming difficult to use the sizing agent when in use.

[0008] Therefore, an object of the present invention is to provide a sizing agent for fibers that can suppress crystallization when in an aqueous solution state and has excellent sizing properties.

Means for Solving the Problems

[0009] The sizing agent for fibers according to the present invention for achieving the above object is a sizing agent for fibers containing a vinyl ester resin (A) represented by the following chemical formula (1) and a nonionic surfactant (B). In the following chemical formula (1), vinyl ester resin (A0) where n is 0, vinyl ester resin (A1) where n is 1, vinyl ester resin (A2) where n is 2, vinyl ester resin (A3) where n is 3, vinyl ester resin (A4) where n is 4, and n is 5 10 or less aboveIt contains a vinyl ester resin (A5), and the content ratio of the vinyl ester resin (A0) in the non-volatile content is 5% by mass or more and 40% by mass or less, the content ratio of the vinyl ester resin (A1) is 2% by mass or more and 23% by mass or less, the content ratio of the vinyl ester resin (A2) is 2% by mass or more and 26% by mass or less, the content ratio of the vinyl ester resin (A3) is 1% by mass or more and 20% by mass or less, the content ratio of the vinyl ester resin (A4) is 1% by mass or more and 10% by mass or less, and the content ratio of the vinyl ester resin (A5) is 1% by mass or more and 8% by mass or less. It is characterized by this point.

[0010]

Chemical formula

[0011] R 1 : Each independently an alkylene group having 1 to 3 carbon atoms R 2 ,R 3 : Each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms n: An integer from 0 to 20

[0012] According to this configuration, n is 0, 1, 2, 3, 4, and 5 or more and 10 or less respectively By containing all of the vinyl ester resins (A0) to (A5), the generation of crystals when the sizing agent is made into an aqueous solution can be effectively suppressed, and the sizing property of the fiber material can be realized at a high level.

[0013] A further characteristic configuration of the sizing agent for fibers according to the present invention is that when the total mass of the vinyl ester resin (A1) and the vinyl ester resin (A3) is W1, and the total mass of the vinyl ester resin (A2) and the vinyl ester resin (A4) is W2, the value of W1 / W2 is 0.15 or more and 5 or less.

[0014] According to this configuration, the generation of crystals when the sizing agent is made into an aqueous solution can be further suppressed.

[0015] A further characteristic configuration of the fiber bundling agent according to the present invention is that the value of W1 / W2 is 0.3 or more and less than 2.

[0016] According to this configuration, the generation of crystals when the bundling agent is made into an aqueous solution can be further suppressed.

[0017] A further characteristic configuration of the fiber bundling agent according to the present invention is that when the total content ratio of the vinyl ester resin (A) and the nonionic surfactant (B) is 100% by mass, the vinyl ester resin (A) is contained in a proportion of 10 to 90% by mass, and the nonionic surfactant (B) is contained in a proportion of 10 to 90% by mass.

[0018] According to this configuration, the generation of crystals when the bundling agent is made into an aqueous solution can be effectively suppressed, and the content ratios of the vinyl ester resin (A) and the nonionic surfactant (B) that can achieve a high level of bundling property of the fiber material can be defined.

[0019] A further characteristic configuration of the fiber bundling agent according to the present invention is that it further contains at least one resin (C) selected from vinyl ester resins other than the vinyl ester resin (A), epoxy resins, polyester resins, and urethane resins.

[0020] According to this configuration, by containing any of the above resins (C), it becomes easier to impart bundling property to the fiber material.

[0021] A further characteristic configuration of the fiber bundling agent according to the present invention is that when the total content ratio of the vinyl ester resin (A), the nonionic surfactant (B), and the resin (C) is 100% by mass, the vinyl ester resin (A) is contained in a proportion of 10 to 90% by mass, the nonionic surfactant (B) is contained in a proportion of 5 to 85% by mass, and the resin (C) is contained in a proportion of 5 to 85% by mass.

[0022] According to this configuration, it is possible to effectively suppress crystal generation when the sizing agent is made into an aqueous solution, and it is possible to define the content ratios of the epoxy resin (A), nonionic surfactant (B), and resin (C) that can achieve a higher level of fiber material bundling property.

[0023] The characteristic configuration of the fiber according to the present invention lies in that the fiber sizing agent described in any one of the above is adhered.

[0024] According to this configuration, it is easy to apply the present invention to the reinforcement of composite materials using resin, ceramic, metal, etc. as the base material.

[0025] A further characteristic configuration of the fiber according to the present invention lies in that it is a reinforcing fiber.

[0026] According to this configuration, it is even easier to apply the present invention to the reinforcement of composite materials using resin, ceramic, metal, etc. as the base material.

[0027] A further characteristic configuration of the fiber sizing agent according to the present invention lies in that the above-mentioned fiber sizing agent is adhered to carbon fiber or glass fiber.

[0028] According to this configuration, it is particularly easy to apply the present invention to the reinforcement of composite materials using resin, ceramic, metal, etc. as the base material.

Embodiments for Carrying Out the Invention

[0029] Hereinafter, embodiments of the present invention will be described. The fiber sizing agent of the present invention (hereinafter simply referred to as "sizing agent") is a fiber sizing agent containing a vinyl ester resin (A) represented by the following chemical formula (1) and a nonionic surfactant (B), and in the following chemical formula (1), it is characterized by containing a vinyl ester resin (A1) where n is 1, a vinyl ester resin (A2) where n is 2, a vinyl ester resin (A3) where n is 3, and a vinyl ester resin (A4) where n is 4.

Chem.

[0030] R 1 : Each independently represents an alkylene group having 1 to 3 carbon atoms R 2 ,R 3 : Each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms n: An integer from 0 to 20

[0031] In the present invention, a vinyl ester resin (A) in which n is any integer from 1 to 4 is contained. That is, the focusing agent of the present invention contains all of a vinyl ester resin (A1) in which n is 1, a vinyl ester resin (A2) in which n is 2, a vinyl ester resin (A3) in which n is 3, and a vinyl ester resin (A4) in which n is 4. If this requirement is satisfied, the focusing agent of the present invention may also contain other vinyl ester resins (A) with n, particularly n = 0.

[0032] R 1 is an alkylene group having 1 to 3 carbon atoms, and can be, for example, a methylene group or an isopropylidene group.

[0033] R 2 ,R 3 The alkyl group having 1 to 4 carbon atoms in can be, for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, or a tert-butyl group.

[0034] The vinyl ester resin (A) represented by the above chemical formula (1) can be a reaction product of an epoxy resin and methacrylic acid or acrylic acid. In addition, the quantitative ratio of the reaction substrates when producing the reaction product may be such that the epoxy value of the epoxy resin is equal to the acid value of methacrylic acid, or either one may be made larger.

[0035] The separation and purification of the epoxy resin can be produced, for example, as follows, but is not limited thereto.

[0036] That is, for example, a mixture of epoxy resins with different molecular weights is dissolved in a solvent (tetrahydrofuran) as a raw material, and the epoxy resins are fractionated by molecular weight using a GPC fractionation apparatus. The fractionated solution is charged into a reaction vessel (a four-necked glass flask reaction vessel) equipped with a heating and cooling device and a stirring device, and the solvent (tetrahydrofuran) is gradually removed by reducing the pressure to 20 mmHg at, for example, 80 to 100 °C, and the epoxy resin can be separated and purified.

[0037] The mixture of epoxy resins may be, for example, the jER (registered trademark) series (jER (registered trademark) 828, jER (registered trademark) 834, jER (registered trademark) 1001, jER (registered trademark) 1002, jER (registered trademark) 1004, etc.) manufactured by Mitsubishi Chemical Corporation, the NPES series (NPES301, NPES302, etc.) manufactured by NAN YA PLASTIC CORPORATION, and the Sumiepoxy (registered trademark) series (Sumiepoxy (registered trademark) ELM-434, Sumiepoxy (registered trademark) ELM-100, etc.) manufactured by Sumitomo Chemical Co., Ltd., but is not limited thereto.

[0038] Using the above-separated and purified epoxy resin and methacrylic acid (or acrylic acid), a vinyl ester resin (A) can be produced as follows.

[0039] That is, an epoxy resin and methacrylic acid (or acrylic acid) are added to a container such as a flask and heated to, for example, 60 °C, and then hydroquinone and triethylamine are added, followed by raising the temperature to 100 °C and reacting until the acid value becomes 1 or less to obtain a vinyl ester resin.

[0040] The nonionic surfactant (B) can be any nonionic surfactant commonly used in the art. The nonionic surfactant (B) may be a single compound or a mixture of a plurality of compounds.

[0041] The nonionic surfactant (B) can be, for example, an alkylene oxide adduct of a compound having a hydroxy group. Examples of the compound having a hydroxy group include aromatic alcohols such as tristyrenated phenol, distyrenated phenol, and bisphenol A, and aliphatic alcohols such as dodecyl alcohol, isododecyl alcohol, tetradecyl alcohol, tridecyl alcohol, secondary dodecyl alcohol, secondary tridecyl alcohol, 2-ethylhexyl alcohol, oleyl alcohol, and isononyl alcohol. Among them, aromatic alcohols are preferred. Examples of the alkylene oxide include, but are not limited to, ethylene oxide and propylene oxide. Therefore, the nonionic surfactant (B) can preferably be an alkylene oxide adduct of an aromatic alcohol.

[0042] In the nonionic surfactant (B), a plurality of types of alkylene oxides may be used in combination. The number of moles of the added alkylene oxide can be, but is not limited to, 6 moles or more and 40 moles or less per mole of the nonionic surfactant (B).

[0043] The nonionic surfactant (B) may be a single compound or a mixture of a plurality of compounds.

[0044] It is considered that the aggregating agent crystallizes when the vinyl ester resin (A0) precipitates. By containing all of the vinyl ester resins (A1) to (A4) as in the aggregating agent of the present invention, the molecular weight distribution becomes continuous (smooth), and it is considered that the vinyl ester resin (A0) is less likely to precipitate. Therefore, by containing all of the vinyl ester resins (A1) to (A4) where n is 1 to 4 as in this configuration, the generation of crystals when the aggregating agent is made into an aqueous solution can be effectively suppressed, and the aggregating property of the fiber material can be realized at a high level.

[0045] When the total mass of vinyl ester resin (A1) and vinyl ester resin (A3) is W1, and the total mass of vinyl ester resin (A2) and vinyl ester resin (A4) is W2, the value of W1 / W2 is preferably 0.15 or more and 5 or less, and more preferably 0.3 or more and less than 2.

[0046] In this configuration, the mass ratio between the total mass W1 of vinyl ester resin (A1) and vinyl ester resin (A3) and the total mass W2 of vinyl ester resin (A2) and vinyl ester resin (A4) is defined.

[0047] In this configuration, the generation of crystals when the aggregating agent is made into an aqueous solution can be further suppressed.

[0048] When the total content ratio of vinyl ester resin (A) and nonionic surfactant (B) in the aggregating agent of the present invention is 100% by mass, it is preferable that the vinyl ester resin (A) is contained in a proportion of 10 to 90% by mass and the nonionic surfactant (B) is contained in a proportion of 10 to 90% by mass.

[0049] In this configuration, the generation of crystals when the aggregating agent is made into an aqueous solution can be effectively suppressed, and the content ratios of vinyl ester resin (A) and nonionic surfactant (B) that can achieve a high level of fiber material aggregability can be defined.

[0050] The aggregating agent of the present invention preferably further contains at least one resin (C) selected from vinyl ester resins other than vinyl ester resin (A), epoxy resins, polyester resins, and urethane resins.

[0051] The vinyl ester resin may be a vinyl ester resin other than vinyl ester resin (A), and for example, a single-terminal type vinyl ester resin can be used.

[0052] As the epoxy resin, any of the epoxy resins exemplified above can be used.

[0053] The polyester resin is a copolymer of a diol monomer and a dicarboxylic acid monomer. Therefore, the polyester resin has, in its molecule, a diol residue which is a partial structure derived from the diol monomer (a diol compound or its derivative), and a dicarboxylic acid residue which is a partial structure derived from the dicarboxylic acid monomer (a dicarboxylic acid or its derivative). The composition of the polyester resin is specified by the ratio (molar ratio) of the monomers constituting the molecule.

[0054] As the diol monomer constituting the polyester resin, one or more kinds of diol compounds may be included. Examples of the diol compound include, but are not limited to, ethylene glycol, diethylene glycol, bisphenol A, an ethylene oxide adduct of bisphenol A (Newpol (registered trademark) BPE series manufactured by Sanyo Chemical Industries, Ltd. (Newpol (registered trademark) BPE-20, Newpol (registered trademark) BPE-40, Newpol (registered trademark) BPE-100, etc.)), a propylene oxide adduct of bisphenol A (Newpol (registered trademark) BP series manufactured by Sanyo Chemical Industries, Ltd. (Newpol (registered trademark) BP-2P, Newpol (registered trademark) BP-3P, Newpol (registered trademark) BP-5P, etc.)).

[0055] As the dicarboxylic acid monomer constituting the polyester resin, one or more kinds of dicarboxylic acid compounds may be included. Examples of the dicarboxylic acid compound include, but are not limited to, isophthalic acid, terephthalic acid, fumaric acid, maleic acid, an alkali metal salt of 5-sulfoisophthalic acid (sodium salt, potassium salt, lithium salt, etc.).

[0056] Non-limiting examples of polyester resins include copolymers of diethylene glycol, isophthalic acid, and sodium 5-sulfoisophthalate; copolymers of ethylene glycol, diethylene glycol, isophthalic acid, terephthalic acid, and sodium 5-sulfoisophthalate; copolymers of an ethylene oxide adduct of bisphenol A and fumaric acid (in other words, a copolymer of bisphenol A, ethylene glycol, and fumaric acid); copolymers of an ethylene oxide adduct of bisphenol A and maleic acid (in other words, a copolymer of bisphenol A, ethylene glycol, and maleic acid). Note that the polyester resin may be a single compound or a mixture of multiple compounds.

[0057] The urethane resin can be, but is not limited to, DISPERCOLL U 54 (manufactured by Covestro), Superflex 500M (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), Superflex 650 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), Superflex 860 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), Superflex E-2000 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), etc.

[0058] By containing any of the above resins (C), it becomes easier to impart cohesiveness to the fiber material.

[0059] When the total content ratio of the vinyl ester resin (A), nonionic surfactant (B), and resin (C) in the sizing agent of the present invention is 100% by mass, it is preferable to contain the vinyl ester resin (A) in a proportion of 10 to 90% by mass, the nonionic surfactant (B) in a proportion of 5 to 85% by mass, and the resin (C) in a proportion of 5 to 85% by mass.

[0060] According to this configuration, it is possible to effectively suppress crystal generation when the sizing agent is made into an aqueous solution, and it is possible to define the content ratios of the vinyl ester resin (A), nonionic surfactant (B), and resin (C) that can achieve a higher level of cohesiveness of the fiber material.

[0061] (Other components) The sizing agent according to this embodiment may contain a vinyl ester resin (A), a nonionic surfactant (B), and other components such as a resin (C). Examples of such other components include, but are not limited to, preservatives, antistatic agents, antioxidants, ultraviolet absorbers, defoaming agents (such as modified silicone), and resins other than the resin (C).

[0062] Also, as a typical mode when the sizing agent is used for sizing treatment of fiber materials, a mode in which the non-volatile content such as the vinyl ester resin (A) is diluted with a diluent (generally also referred to as a sizing solution) is exemplified. Such a diluent is also an example of other components. Examples of the diluent include, but are not limited to, water (such as tap water, industrial water, ion-exchanged water, distilled water), acetone, methyl ethyl ketone, N-methyl-2-pyrrolidone, etc. The concentration of the non-volatile content in the sizing agent in the form of being diluted with a diluent is not particularly limited, but can be, for example, 10% by mass or more and 60% by mass or less. The non-volatile content of the sizing agent refers to the component that remains without volatilization after heating the sizing agent in a hot air dryer at 105 °C for 2 hours, and the concentration refers to the ratio of the mass of the non-volatile content in the sizing agent to the mass of the sizing agent.

[0063] 〔Manufacturing method of sizing agent〕 The sizing agent according to this embodiment can be obtained by mixing the vinyl ester resin (A), the nonionic surfactant (B), and optionally added components by a known method. For example, it can be manufactured by adding water over 5 hours while stirring the vinyl ester resin (A), the nonionic surfactant (B), and optionally added components at a temperature between 20 °C and 90 °C.

[0064] 〔Usage method of sizing agent〕 The sizing agent according to this embodiment is used for sizing treatment of fiber materials. The sizing treatment is a process of attaching a sizing agent to the fiber material, and as a method thereof, a method usually used in the art for attaching this type of sizing agent to the fiber material can be applied. That is, an immersion oiling method, a spray oiling method, a roller oiling method, a guide oiling method, etc. can be adopted. In addition, when applying each method, the sizing agent can be appropriately diluted with a diluent such as water.

[0065] The amount of the sizing agent attached to the fiber material is not particularly limited. For example, it is preferable that the sizing agent is attached in an amount of 0.1% by mass or more and 3% by mass or less based on the entire fiber material to which the sizing agent is attached.

[0066] In addition, when the sizing agent according to this embodiment is applied during the production of reinforcing fibers, reinforcing fibers with the sizing agent attached to the fiber material can be obtained. These reinforcing fibers are an example of the fibers according to the present invention. The fiber material is preferably an inorganic fiber, and in this case, the reinforcing fiber is an inorganic fiber with the sizing agent attached. Further, it is more preferable that the inorganic fiber is a carbon fiber or a glass fiber.

[0067] These reinforcing fibers can be used in composite materials having a base material such as resin, ceramic, or metal. A composite material characterized by including the above reinforcing fibers and a matrix resin which is a thermosetting resin is an embodiment of the present invention.

[0068] 〔Other Embodiments〕 The present invention may be a sizing agent for fibers containing a vinyl ester resin (A) represented by the following chemical formula (1) and a nonionic surfactant (B), and in the following chemical formula (1), a vinyl ester resin (A1) in which n is 1, a vinyl ester resin (A2) in which n is 2, a vinyl ester resin (A3) in which n is 3, and a vinyl ester resin (A4) in which n is 4 are contained. In chemical formula (1), R 1 is each independently an alkylene group having 1 to 3 carbon atoms, R 2 and R 3is independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and n is an integer of 0 or more and 20 or less. According to this configuration, by containing all of the vinyl ester resins (A1) to (A4) in which n is 1 to 4, the generation of crystals when the sizing agent is made into an aqueous solution can be effectively suppressed, and the sizing property of the fiber material can be realized at a high level.

Chemical formula

[0069] Regarding other configurations as well, it should be understood that all the embodiments disclosed in this specification are illustrative in all respects, and the scope of the present invention is not limited thereby. Those skilled in the art will easily understand that appropriate modifications can be made without departing from the spirit of the present invention. Therefore, other embodiments modified without departing from the spirit of the present invention are naturally included in the scope of the present invention.

Examples

[0070] 〔Example 1〕 The vinyl ester resin (A) represented by the above chemical formula (1) was produced by the following method.

[0071] First, the raw material epoxy resin was separated and purified. 400 g of jER (registered trademark) 1001 (manufactured by Mitsubishi Chemical Corporation) as an epoxy resin was dissolved in tetrahydrofuran so that the solid content concentration became 2%, and the epoxy resin was fractionated by molecular weight using a GPC fractionation apparatus (Recycling fractionation HPLC: LC-9130NEXT (manufactured by Japan Analytical Industry Co., Ltd.)). Then, each fractionated solution was charged into a reaction vessel (glass four-necked flask reaction vessel) equipped with a heating and cooling device and a stirring device, and the pressure was gradually reduced to 20 mmHg at 90 °C to remove tetrahydrofuran, and the following compounds (a-0) to (a-5) (epoxy resins) were obtained.

[0072] · Bisphenol type epoxy resin (a-0) (molecular weight 340) in which p in chemical formula (2) is 0 · Bisphenol type epoxy resin (a-1) (molecular weight 624) in which p in chemical formula (2) is 1 · Bisphenol-type epoxy resin (a-2) with p = 2 in Chemical Formula (2) (molecular weight 908) · Bisphenol-type epoxy resin (a-3) with p = 3 in Chemical Formula (2) (molecular weight 1192) · Bisphenol-type epoxy resin (a-4) with p = 4 in Chemical Formula (2) (molecular weight 1476) · Bisphenol-type epoxy resin (a-5) with p ranging from 5 to 10 in Chemical Formula (2) (Mn 1760 or more)

[0073]

Chemical formula

[0074] Epoxy resins (a-0) to (a-5) are each a compound in which R in Chemical Formula (2) 4 is an isopropylidene group.

[0075] Using any one of the epoxy resins (a-0) to (a-5) manufactured as described above, and methacrylic acid or acrylic acid, vinyl ester resin (A) was manufactured as follows.

[0076] 344 parts by mass of epoxy resin (a-0) and 172 parts by mass of methacrylic acid were added to a four-necked flask made of glass, heated to 60 °C while stirring, then 0.5 part by mass of hydroquinone and 0.5 part by mass of triethylamine were added, and then the temperature was raised to 100 °C and reacted until the acid value became 1 or less to produce vinyl ester resin (A0-1) with n = 0.

[0077] Also, 344 parts by mass of epoxy resin (a-0) and 144 parts by mass of acrylic acid were added to a four-necked flask made of glass, heated to 60 °C while stirring, then 0.5 part by mass of hydroquinone and 0.5 part by mass of triethylamine were added, and then the temperature was raised to 100 °C and reacted until the acid value became 1 or less to produce vinyl ester resin (A0-2) with n = 0.

[0078] Also, 344 parts by mass of epoxy resin (a-0), 86 parts by mass of methacrylic acid, and 72 parts by mass of acrylic acid were added to a four-necked flask made of glass, and the mixture was heated to 60 °C with stirring. After adding 0.5 part by mass of hydroquinone and 0.5 part by mass of triethylamine, the temperature was raised to 100 °C and reacted until the acid value became 1 or less to produce a vinyl ester resin (A0-3) with n = 0.

[0079] In the above method, vinyl ester resins (A1-1) to (A1-3) with n = 1 were produced by replacing epoxy resin (a-0) with epoxy resin (a-1), vinyl ester resins (A2-1) to (A2-3) with n = 2 were produced by replacing epoxy resin (a-0) with epoxy resin (a-2), vinyl ester resins (A3-1) to (A3-3) with n = 3 were produced by replacing epoxy resin (a-0) with epoxy resin (a-3), vinyl ester resins (A4-1) to (A4-3) with n = 4 were produced by replacing epoxy resin (a-0) with epoxy resin (a-4), and vinyl ester resins (A5-1) to (A5-3) with n = 5 10 or less above were produced by replacing epoxy resin (a-0) with epoxy resin (a-5).

[0080] The outline of the produced vinyl ester resin (A) is shown in Table 1.

[0081]

Table 1

[0082] In addition, in A0-3, for convenience in Table 1, [R 2 : methyl group, R 3 : hydrogen atom] is described, but A0-3 is a mixture of compounds having the following functional groups. The same applies to A1-3 to A5-3. [R 2 : methyl group, R 3 : methyl group] [R 2 : hydrogen atom, R3 : Hydrogen atom [R 2 : Hydrogen atom, R 3 : Methyl group

[0083] [Example 2] The flocculant of the present invention was produced by the above-described method for producing a flocculant (Examples 1 to 26 of the present invention). That is, it was produced by adding water over 5 hours while stirring a vinyl ester resin (A), a nonionic surfactant (B), and optionally added components at a temperature between 20°C and 90°C.

[0084] In Examples 1 to 6 of the present invention, the vinyl ester resin (A) contains vinyl ester resins (A0-1) to (A5-1), the nonionic surfactant (B) contains at least one of (B-1) to (B-3) shown below, and the resin (C) contains at least one of (EP-1), (PE-1), (PE-2), (PU-1), (VE-1), and (VE-2) shown below.

[0085] Also, in Examples 7 to 12 of the present invention, the vinyl ester resin (A) contains vinyl ester resins (A0-2) to (A5-2), the nonionic surfactant (B) contains at least one of (B-1) to (B-3) shown below, and the resin (C) contains at least one of (EP-1), (PE-1), (PE-2), (PU-1), (VE-1), and (VE-2) shown below.

[0086] Also, in Examples 13 to 17 of the present invention, the vinyl ester resin (A) contains vinyl ester resins (A0-3) to (A5-3), the nonionic surfactant (B) contains at least one of (B-1) to (B-3) shown below, and the resin (C) contains at least one of (EP-1), (PE-1), (PE-2), (PU-1), and (VE-1) shown below.

[0087] Also, in Invention Example 18, the vinyl ester resin (A) contains vinyl ester resins (A0-1), (A2-2), (A1-3), (A3-3), (A4-3), (A5-3), the nonionic surfactant (B) contains (B-1) and (B-3) shown below, and the resin (C) contains (VE-1).

[0088] Also, in Invention Examples 19 to 26, the vinyl ester resin (A) contains vinyl ester resins (A0-1) to (A5-1), and the nonionic surfactant (B) contains at least one of (B-1) and (B-2) shown below.

[0089] The mass percentages (total 100 mass%) of the vinyl ester resin (A), nonionic surfactant (B), and resin (C) in Invention Examples 1 to 18 are shown in Tables 2-1 and 2-2, and the mass percentages (total 100 mass%) of the vinyl ester resin (A) and nonionic surfactant (B) in Invention Examples 19 to 26 are shown in Tables 2-2 and 2-3.

[0090] [Table 2-1]

[0091] [Table 2-2]

[0092] [Table 2-3]

[0093] (B-1): A compound obtained by adding 30 moles of ethylene oxide and 6 moles of propylene oxide to 1 mole of tristyrenated phenol (B-2): A compound obtained by adding 27 moles of ethylene oxide to 1 mole of tristyrenated phenol (B-3): A compound obtained by adding 18 moles of ethylene oxide to 1 mole of bisphenol A

[0094] (EP-1): Sumiepoxy (registered trademark) ELM-434 (manufactured by Sumitomo Chemical Co., Ltd.) (epoxy resin) (PE-1): Polyester resin with a molar ratio of 5-sodium sulfoisophthalic acid: isophthalic acid: diethylene glycol of 4:46:50 and a number average molecular weight of 15,000 (PE-2): Fumaric acid and Newpol BPE-20 (manufactured by Sanyo Chemical Industries, Ltd.) reacted in a molar ratio of 3:4 to produce a polyester resin (PU-1): Urethane resin which is the non-volatile resin part of DISPERCOLL U 54 (manufactured by Covestro) (VE-1): VE-1 (mono-terminal vinyl ester epoxy resin) synthesized by the method described below (VE-2): VE-2 (mono-terminal vinyl ester epoxy resin) synthesized by the method described below

[0095] VE-1 was manufactured as follows. 344 parts by mass of epoxy resin (a-0) and 86 parts by mass of methacrylic acid were added to a four-necked flask made of glass, heated to 60 °C with stirring, then 0.5 parts by mass of hydroquinone and 0.5 parts by mass of triethylamine were added, and the temperature was raised to 100 °C and reacted until the acid value became 1 or less to obtain a reaction product. 400 g of this reaction product was dissolved in tetrahydrofuran so that the solid content concentration became 2%, and the reaction product was fractionated by molecular weight using the above GPC fractionation apparatus. Then, each fractionated solution was charged into the above reaction vessel equipped with a heating and cooling device and a stirring device, and the pressure was gradually reduced to 20 mmHg at 90 °C to remove tetrahydrofuran, and R in Chemical Formula (3) 5 is an isopropylidene group, q is 0, R 6 is a methyl group to obtain compound VE-1 (molecular weight 430).

[0096]

Chemical formula

[0097] VE-2 was manufactured as follows. 624 parts by mass of epoxy resin (a-0) and 86 parts by mass of methacrylic acid were added to a four-necked flask made of glass, and the mixture was heated to 60 °C with stirring. Then, 0.8 parts by mass of hydroquinone and 0.8 parts by mass of triethylamine were added, and the temperature was raised to 100 °C and reacted until the acid value became 1 or less to obtain a reaction product. 400 g of this reaction product was dissolved in tetrahydrofuran so that the solid content concentration became 2%, and the reaction product was fractionated by molecular weight using the above GPC fractionation apparatus. Then, each fractionated solution was charged into the above reaction vessel equipped with a heating and cooling device and a stirring device, and the pressure was gradually reduced to 20 mmHg at 90 °C to remove tetrahydrofuran, and R in Chemical Formula (3) 5 is an isopropylidene group, q is 1, and R 6 is a methyl group to obtain Compound VE-2 (molecular weight 710).

[0098] Also, when the total mass of vinyl ester resin (A1-1) and vinyl ester resin (A3-1) is W1, and the total mass of vinyl ester resin (A2-1) and vinyl ester resin (A4-1) is W2, the values of W1 / W2 are shown in Tables 2-1 to 2-3.

[0099] The aggregating agents of the comparative examples were produced by the above method for producing an aggregating agent (Comparative Examples 1 and 2). In Comparative Example 1, the vinyl ester resin (A) contains vinyl ester resins (A0-1), (A2-1) to (A5-1), and the nonionic surfactant (B) contains (B-1). In Comparative Example 2, the vinyl ester resin (A) contains vinyl ester resins (A0-1) to (A2-1), and the nonionic surfactant (B) contains (B-1). The mass percentages of the vinyl ester resin (A) and the nonionic surfactant (B) in Comparative Examples 1 and 2 are shown in Table 2-3 (total 100 mass%).

[0100] <Evaluation Method> Regarding the above Examples 1 to 26 of the present invention and Comparative Examples 1 and 2, the crystal growth inhibitory property and the aggregating property of the aggregating agent were evaluated.

[0101] The crystallization inhibition property was evaluated by preparing 100 mL of a 30% by mass aqueous solution of the sizing agent in each example of the present invention and each comparative example, sealing it in a transparent glass bottle with a capacity of 140 mL, allowing it to stand at 0 °C for 10 days, and then evaluating the crystalline deposits accumulated at the bottom according to the following criteria.

[0102] S: No crystalline deposits were observed, and the crystallization inhibition property was very good. A: Crystalline deposits were deposited on the bottom of the glass bottle, but the area was less than 10% of the bottom area, and the crystallization inhibition property was good. B: Crystalline deposits were deposited on the bottom of the glass bottle, but the area was 10% or more and less than 20% of the bottom area, and the crystallization inhibition property was at an acceptable level. C: A large amount of crystalline deposits were deposited on the bottom of the glass bottle, occupying 20% or more of the bottom area, and the crystallization inhibition property was poor.

[0103] The sizing property was evaluated by filling a sizing bath with a sizing liquid (non-volatile content concentration: 4%) containing the sizing agent in each example of the present invention and each comparative example, and applying the sizing agent to a fiber material (carbon fiber or glass fiber) by passing the fiber material through the sizing bath. After applying the sizing agent, the roll of the fiber material was set on a creel and unwound at a speed of 5 m per minute, and the state of the fiber material when passing through a roller immediately after unwinding was observed. According to the observation results, the sizing property of the fiber material brought about by the sizing agent in each example of the present invention and each comparative example was evaluated in the following three grades.

[0104] A: Almost no fiber material was wound around the roller, and the aggregation of the passed fiber material was good. B: A small amount of fiber material was wound around the roller, but the aggregation of the passed fiber material was good. C: A large amount of fiber material was wound around the roller, and the passed fiber material was scattered.

[0105] <Evaluation Results> The evaluation results of the crystallization inhibition property and sizing property of each example of the present invention and each comparative example are shown in Tables 2-1 to 2-3.

[0106] In terms of crystal inhibition, for Invention Examples 1 to 21 of the present invention, an S evaluation (very good), for Invention Examples 22 to 24, an A evaluation (good), and for Invention Examples 25 and 26, a B evaluation (acceptable level) were respectively obtained. That is, it was recognized that for Invention Examples 1 to 26 of the present invention, crystals can be effectively inhibited.

[0107] At this time, the value of W1 / W2 was 0.333 to 1.875 in Invention Examples 1 to 21 (S evaluation), 0.208 to 4.667 in Invention Examples 22 to 24 (A evaluation), and 0.111 to 5.429 in Invention Examples 25 and 26 (B evaluation).

[0108] On the other hand, for Comparative Examples 1 and 2, a C evaluation (poor) was respectively obtained.

[0109] The focusing agent of the present invention (Invention Examples 1 to 26) contains all of the vinyl ester resins (A1-1) to (A4-1). In contrast, Comparative Example 1 does not contain the vinyl ester resin (A1-1), and Comparative Example 2 does not contain the vinyl ester resins (A3-1) and (A4-1). It is considered that the focusing agent crystallizes by the precipitation of the vinyl ester resin (A0-1). From the above results, by containing all of the vinyl ester resins (A1-1) to (A4-1) like the focusing agent of the present invention, the molecular weight distribution becomes more continuous (smooth) than each comparative example, and it is considered that the precipitation of the vinyl ester resin (A0-1) becomes difficult.

[0110] The values of W1 / W2 were 0.125 and 2.000 in Comparative Examples 1 and 2 respectively.

[0111] From the above, it was recognized that the lower limit of W1 / W2 is greater than 0.125, for example, 0.15, and preferably 0.3. Also, it was recognized that the upper limit of W1 / W2 is 5.429 or less, for example, 5.000 or less, and preferably less than 2.000.

[0112] That is, if the value of W1 / W2 is 0.15 or more and 5 or less, crystal generation can be further suppressed, which is preferable. Further, if the value of W1 / W2 is 0.3 or more and less than 2, it has been found that crystal generation can be further suppressed, which is more preferable.

[0113] In terms of the focusing property, for Invention Examples 1 to 18 of the present invention, Evaluation A (almost no winding was observed), and for Invention Examples 19 to 26 of the present invention, Evaluation B (slight winding was observed) were respectively obtained. That is, for Invention Examples 1 to 26 of the present invention, it was above the allowable level.

[0114] At this time, Invention Examples 1 to 18 contain vinyl ester resin (A), nonionic surfactant (B), and resin (C), and Invention Examples 19 to 26 contain epoxy resin (A) and nonionic surfactant (B).

[0115] That is, it was recognized that by containing any of the above resins (C) as in Invention Examples 1 to 18 (Evaluation A), it is easier to impart a focusing property to the fiber material than in the case of not containing resin (C) (Invention Examples 19 to 26).

[0116] In Invention Examples 19 to 26, the total content ratio of vinyl ester resin (A) and nonionic surfactant (B) was 100% by mass. That is, in Invention Examples 19 to 26, the content ratio of vinyl ester resin (A) was 67 to 76% by mass, and the content ratio of nonionic surfactant (B) was 24 to 33% by mass.

[0117] It was recognized that when the abundance ratio of each constituent component satisfies the above requirements, crystal generation when the aggregating agent is made into an aqueous liquid can be effectively suppressed, and the focusing property of the fiber material can be realized at a high level.

[0118] When the total content ratio of vinyl ester resin (A) and nonionic surfactant (B) is 100% by mass (Invention Examples 19 to 26), if vinyl ester resin (A) is contained in a ratio of 10 to 90% by mass and nonionic surfactant (B) is contained in a ratio of 10 to 90% by mass, the same effects as above are considered to be obtained.

[0119] In Invention Examples 1 to 18, the total content ratio of vinyl ester resin (A), nonionic surfactant (B), and resin (C) was 100% by mass. That is, in Invention Examples 1 to 18, the content ratio of vinyl ester resin (A) was 18 to 58% by mass, the content ratio of nonionic surfactant (B) was 15 to 30% by mass, and the content ratio of resin (C) was 20 to 52% by mass.

[0120] It was recognized that when the proportion of each component satisfied the above requirements, the generation of crystals when the sizing agent was made into an aqueous solution could be effectively suppressed, and the sizing property of the fiber material could be realized at a higher level.

[0121] When the total content ratio of epoxy resin (A), nonionic surfactant (B), and resin (C) was 100% by mass, if epoxy resin (A) was contained at a ratio of 10 to 90% by mass, nonionic surfactant (B) was contained at a ratio of 5 to 85% by mass, and resin (C) was contained at a ratio of 5 to 85% by mass, it was considered that the same effect as above could be obtained.

Industrial Applicability

[0122] The present invention can be used, for example, for sizing treatment of fiber materials.

Claims

1. A fiber sizing agent containing a vinyl ester resin (A) represented by the following chemical formula (1) and a nonionic surfactant (B), A fiber sizing agent characterized by containing a vinyl ester resin (A1) in which n is 1, a vinyl ester resin (A2) in which n is 2, a vinyl ester resin (A3) in which n is 3, and a vinyl ester resin (A4) in which n is 4 in the following chemical formula (1). 【Chemical 1】 R １ : each independently an alkylene group having 1 to 3 carbon atoms R ２ , R ３ : each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms n: An integer of 0 or more and 20 or less

2. The fiber sizing agent according to claim 1, wherein when the total mass of the vinyl ester resin (A1) and the vinyl ester resin (A3) is W1 and the total mass of the vinyl ester resin (A2) and the vinyl ester resin (A4) is W2, the value of W1 / W2 is 0.15 or more and 5 or less.

3. The fiber sizing agent according to claim 2, wherein the value of W1 / W2 is 0.3 or more and less than 2.

4. The fiber sizing agent according to claim 1, wherein when the total content ratio of the vinyl ester resin (A) and the nonionic surfactant (B) is 100% by mass, the vinyl ester resin (A) is contained in a proportion of 10 to 90% by mass, and the nonionic surfactant (B) is contained in a proportion of 10 to 90% by mass.

5. The fiber sizing agent according to claim 1, further containing at least one resin (C) selected from vinyl ester resins other than the vinyl ester resin (A), epoxy resins, polyester resins, and urethane resins.

6. The fiber sizing agent according to claim 5, wherein when the total content ratio of the vinyl ester resin (A), the nonionic surfactant (B), and the resin (C) is 100% by mass, the vinyl ester resin (A) is contained in a proportion of 10 to 90% by mass, the nonionic surfactant (B) is contained in a proportion of 5 to 85% by mass, and the resin (C) is contained in a proportion of 5 to 85% by mass.

7. A fiber characterized by having the fiber sizing agent according to any one of claims 1 to 6 attached thereto.

8. The fiber according to claim 7, which is a reinforcing fiber.

9. The fiber according to claim 7, wherein the fiber sizing agent is attached to carbon fiber or glass fiber.

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