JP7175422B1 - Fiber sizing agent composition and fiber sizing agent solution - Google Patents

Abstract

The present invention provides a fiber sizing agent that suppresses fluffing and exhibits excellent adhesion between fibers and a matrix resin. A fiber sizing agent composition containing an aromatic epoxy resin (A) and a nonionic surfactant (B), wherein the number of epoxy functional groups per molecule of the aromatic epoxy resin (A) is 1. .80 to 1.95, and the aromatic epoxy resin (A) contains a bisphenol type epoxy resin having a number average molecular weight of 330 to 1200 in an amount of 50% by weight or more based on the total weight of the aromatic epoxy resin (A). [Selection figure] None

Description

The present invention relates to a fiber sizing agent composition and a fiber sizing agent solution.

In recent years, composite materials of matrix resins such as unsaturated polyester resins, phenolic resins, epoxy resins and polypropylene resins and various fibers have been widely used in fields such as sports equipment, leisure goods and aircraft. Fibers such as glass fibers, carbon fibers, ceramic fibers, metal fibers, mineral fibers, rock fibers and slag fibers are used in these composite materials. These fibers are usually provided with a sizing agent in the process of forming the composite material (see, for example, Patent Document 1).

WO2013/146024

In order to improve the physical properties of the composite material, it is important that the adhesiveness between the fiber and the matrix resin is high from the viewpoint of effectively utilizing the properties of the fiber, and that there is little fluffing from the viewpoint of the handleability of the fiber bundle.
However, the conventional technology has not been able to sufficiently improve the above characteristics, and there is room for improvement.

An object of the present invention is to provide a fiber sizing agent that suppresses fluffing and has excellent adhesion between fibers and a matrix resin.

The present inventor has arrived at the present invention as a result of conducting studies to achieve the above object.
That is, the present invention provides a fiber sizing agent composition containing an aromatic epoxy resin (A) and a nonionic surfactant (B), wherein the number of epoxy functional groups per molecule of the aromatic epoxy resin (A) is is 1.80 to 1.95, and the aromatic epoxy resin (A) is a bisphenol type epoxy resin having a number average molecular weight of 330 to 1200, and 50% by weight or more based on the total weight of the aromatic epoxy resin (A). a fiber sizing agent composition comprising: a fiber sizing agent solution in which the fiber sizing agent composition is dissolved or dispersed in a solvent containing at least one selected from the group consisting of water and organic solvents.

According to the present invention, it is possible to provide a fiber sizing agent that suppresses fluffing and has excellent adhesion between the fibers and the matrix resin.

FIG. 1 is a side view schematically showing the arrangement of carbon fiber bundles in evaluation of fluffiness.

<Fiber sizing agent composition>
The fiber sizing agent composition of the present invention contains an aromatic epoxy resin (A) and a nonionic surfactant (B). In the present invention, the number of epoxy functional groups per molecule of the aromatic epoxy resin (A) contained in the fiber sizing agent composition is 1.80 to 1.95. When the number of epoxy functional groups per molecule of the aromatic epoxy resin (A) is from 1.80 to 1.95, it is possible to suppress fluffing and sufficiently improve the adhesiveness between the fiber and the matrix resin.

In the present invention, if the number of epoxy functional groups per molecule of the aromatic epoxy resin (A) is less than 1.80, the adhesiveness between the fiber and the matrix resin may be insufficient. If it exceeds 0.95, the anti-fluffing effect may be insufficient. The number of epoxy functional groups per molecule of the aromatic epoxy resin (A) is preferably 1.82 or more, more preferably 1.85 or more, from the viewpoint of adhesion between the fiber and the matrix resin. From the viewpoint, it is preferably 1.93 or less, more preferably 1.90 or less.

The number of epoxy functional groups per molecule of the aromatic epoxy resin (A) can be calculated based on the following formula.
Number of epoxy functional groups per molecule of (A) = [Number average molecular weight of (A)]/[Epoxy equivalent weight of (A)]

The number average molecular weight (Mn) of the aromatic epoxy resin (A) can be measured at 40°C by gel permeation chromatography (hereafter GPC).
GPC measurement conditions can be, for example, as follows.
(GPC measurement conditions)
Model: Alliance (liquid chromatograph manufactured by Nippon Waters Co., Ltd.)
Column: Guard column Super HL
+TSK gel Super H4000
+ TSK gel Super H3000
+ TSK gel Super H2000
(both manufactured by Tosoh Corporation)
Column temperature: 40°C
Detector: RI (Refractive Index)
Eluent: tetrahydrofuran Eluent flow rate: 0.6 ml/min Sample concentration: 0.25% by weight
Injection volume: 10 μl
Reference material:
Molecular weight = 228 (Idemitsu Kosan Co., Ltd.; bisphenol A)
Molecular weight = 340 (manufactured by Mitsui Chemicals Fine Co., Ltd.; Epomic R139S)
Molecular weight = 370 (manufactured by Mitsubishi Chemical Corporation; jER828)
Molecular weight = 470 (manufactured by Mitsubishi Chemical Corporation; jER834)
Molecular weight = 900 (manufactured by Mitsubishi Chemical Corporation; jER1001)
Molecular weight = 1200 (manufactured by Mitsubishi Chemical Corporation; jER1002)

The epoxy equivalent of the aromatic epoxy resin (A) can be calculated by the following method.
(1) Accurately weigh 0.6 to 0.7 g of a sample into an Erlenmeyer flask.
(2) Add 25 mL (milliliters) of a 0.2 mol/L hydrochloric acid dioxane solution, plug, and stir with a magnetic stirrer for 15 minutes at room temperature to react.
(3) After completion of the reaction, wash the inner wall and stopper of the flask with 20 mL of methyl alcohol. Next, about 10 drops of cresol red indicator are added and titrated with 0.1 mol/L potassium hydroxide standard solution (potency: f).
(4) Measure the titer of the blank as well.
(5) Calculate the epoxy equivalent based on the following formula.
Epoxy equivalent (g / eq) = [10000 × {weight of sample (g)}] / [{titration volume of blank (mL)} - {titration volume in (3) (mL)}] × f]

In the present invention, the aromatic epoxy resin (A) contains 50% by weight or more of a bisphenol type epoxy resin having Mn of 330-1200. The aromatic epoxy resin (A) contains a bisphenol-type epoxy resin (A1) having Mn of 330 to 1200 to provide a fiber sizing agent that suppresses fluffing of fiber bundles and has excellent adhesion between the fibers and the matrix resin. can do.
From the viewpoint of suppressing fluffing of the fiber bundle, the content of the bisphenol type epoxy resin (A1) having Mn 330 to 1200 in the aromatic epoxy resin (A) is 55% by weight based on the total weight of the aromatic epoxy resin (A). It is preferably 60% by weight or more, more preferably 60% by weight or more. The bisphenol epoxy resin (A1) having an Mn of 330 to 1,200 is preferably a bisphenol epoxy resin having an Mn of 350 to 1,200 from the viewpoint of suppressing fluffing of the fiber bundle.

In the present invention, the aromatic epoxy resin (A) is preferably a diglycidyl ether of dihydric phenol (e.g. bisphenol compounds such as bisphenol A, bisphenol F and bisphenol S and biphenol compounds) and epihalohydrin (e.g. epichlorohydrin). is a condensed epoxy resin, more preferably a bisphenol-type epoxy resin obtained by condensing a bisphenol compound and epichlorohydrin, and still more preferably a bisphenol A-type epoxy resin obtained by condensing bisphenol A and epichlorohydrin. be. One of the aromatic epoxy resins (A) may be used alone, or two or more of them may be used in combination.

In the present invention, the nonionic surfactant (B) includes, for example, an alkylene oxide (AO) adduct (Mn = 158 to 200,000) of an aliphatic monohydric alcohol (having 8 to 18 carbon atoms), polyhydric ( AO adducts (Mn 500 to 100,000) of dihydric to octahydric) alcohols (carbon atoms 2 to 6; ethylene glycol, propylene glycol, glycerin, pentaerythritol, sorbitan, etc.), AO of higher fatty acids (carbon atoms 12 to 24) Adducts (Mn = 158 to 200,000), AO adducts (Mn 500 to 5,000) of alkylphenols (having 10 to 20 carbon atoms), AO of arylalkylphenols (having 14 to 62 carbon atoms; styrenated phenol, etc.) Adducts (Mn 500-5,000), AO adducts (Mn 500-5,000) of styrenated cumylphenol or styrenated cresol (total number of carbon atoms: 15-61), polyalkylene glycols (Mn 150-6,000) ) and fatty acids having 12 to 24 carbon atoms, polyhydric (divalent to octavalent or higher) alcohols (2 to 32 carbon atoms, such as ethylene glycol, propylene glycol, glycerin, pentaerythritol, sorbitan etc.) and fatty acids having 12 to 24 carbon atoms (for example, lauric acid, stearic acid), AO adducts (Mn 350 to 10,000) of esters, AO adducts of fatty acid amides having 12 to 24 carbon atoms (Mn 200 to 30, 000), AO adducts (Mn 220 to 30,000) of polyhydric (divalent to octavalent or higher) alcohol alkyl (carbon number 8 to 60) ethers.
Alkylene oxide (AO) includes ethylene oxide (EO), propylene oxide (PO) and butylene oxide (BO). PO and BO may be linear or branched. AO may be used alone or in combination of two or more. AO adducts in which two or more types are combined include random adducts, block adducts, and mixed adducts thereof.

Among the above nonionic surfactants (B), from the viewpoint of focusing properties, arylalkylphenols {styrenated phenol (14 to 62 carbon atoms), styrenated cumylphenol and styrenated cresol (15 to 61 carbons) are preferred. etc.}, more preferably an AO adduct of arylalkylphenol, more preferably an AO adduct of styrenated phenol, particularly preferably PO of styrenated phenol and EO adduct.
The nonionic surfactant (B) may be used alone or in combination of two or more.

The method for measuring Mn of the nonionic surfactant (B) is the same as the method for measuring Mn of the above aromatic epoxy resin (A), except that polyethylene glycol is used as the standard substance.

In the fiber sizing agent composition of the present invention, the ratio (W2/W1) to the weight W2 of the nonionic surfactant (B) to the weight W1 of the aromatic epoxy resin (A) is the effect of suppressing fluffing and improving adhesion. From the viewpoint of compatibility, it is preferably 5/95 to 50/50, more preferably 10/90 to 30/70, and even more preferably 20/80 to 35/65.

The content of the aromatic epoxy resin (A) in the sizing agent composition for fibers of the present invention is determined by the weight of the solid content contained in the sizing agent composition for fibers, from the viewpoint of achieving both the effect of suppressing fluffing and the effect of improving adhesiveness. 50 to 95% by weight is preferred, and 70 to 90% by weight is more preferred. Here, the solid content is the residue after heating and drying 1 g of the sample at 130° C. for 45 minutes in a circulating dryer.

The content of the nonionic surfactant (B) in the sizing agent composition for fibers of the present invention is set to Based on weight, 5-50% by weight is preferred, and 10-30% by weight is more preferred.

The fiber sizing agent composition of the present invention may contain components other than the aromatic epoxy resin (A) and the nonionic surfactant (B). Other components include surfactants (C) other than nonionic surfactants, smoothing agents, preservatives and antioxidants.

Surfactants (C) other than nonionic surfactants include known surfactants such as anionic surfactants, cationic surfactants and amphoteric surfactants (for example, JP-A-2006-124877, WO2003/37964 No. 2003-100000), etc. can be mentioned.
Smoothing agents include waxes (polyethylene, polypropylene, oxidized polyethylene, oxidized polypropylene, modified polyethylene, modified polypropylene, etc.), higher fatty acid alkyl (C 1-24) esters (methyl stearate, ethyl stearate, prople stearate). latex, butyl stearate, octyl stearate, stearyl stearate, etc.), higher fatty acids (myristic acid, palmitic acid, stearic acid, etc.), natural oils and fats (coconut oil, beef tallow, olive oil, rapeseed oil, etc.), and liquid paraffin. be done.
Examples of antiseptics include benzoic acids, salicylic acids, sorbic acids, quaternary ammonium salts, imidazoles, and the like.
Antioxidants include phenols (2,6-di-t-butyl-p-cresol, etc.), thiodipropionates (dilauryl 3,3'-thiodipropionate, etc.) and phosphites (triphenyl phosphite, etc.).

The content of other components in the sizing agent composition for fibers of the present invention is preferably 0 to 5% by weight based on the weight of solids contained in the sizing agent composition for fibers, from the viewpoint of excellent sizing properties. , 0 to 2% by weight is more preferred.

The method for producing the fiber sizing agent composition of the present invention is not particularly limited. Other components) are added and stirred at a temperature of preferably 20 to 150° C., more preferably 50 to 120° C. until uniform. The order in which the components [(A), (B) and other components] constituting the composition are added is not particularly limited.

<Fiber sizing agent solution>
The fiber sizing agent solution of the present invention is obtained by dissolving or dispersing the fiber sizing agent composition of the present invention in a solvent containing at least one selected from the group consisting of water and organic solvents. In this specification, water and organic solvents are also referred to as "solvents".
By dissolving or dispersing the fiber sizing agent composition of the present invention in a solvent, it becomes easy to make the amount of the fiber sizing agent composition adhered to the fiber bundles appropriate.

Examples of solvents include water and organic solvents.
Examples of organic solvents include monohydric alcohols having 1 to 4 carbon atoms (methanol, ethanol, isopropanol, etc.), ketones having 3 to 6 carbon atoms (acetone, ethyl methyl ketone, methyl isobutyl ketone, etc.), and 2 to 4 carbon atoms. 6 glycol (ethylene glycol, propylene glycol, diethylene glycol and triethylene glycol, etc.), its mono-lower alkyl (alkyl has 1 to 4 carbon atoms) ether, dimethylformamide, aromatic hydrocarbon (toluene, xylene, etc.), carbon number 3 to 5 acetic acid alkyl esters (methyl acetate, ethyl acetate, etc.) and the like.
One of the above solvents may be used alone, or two or more thereof may be used in combination. Among the above solvents, water and water-miscible organic solvents (at 25 ° C., when mixed with water at a volume ratio of 1:1, are uniformly mixed from the viewpoint of safety against fire, etc.) organic solvent) and water, more preferably water.

From the viewpoint of cost and the like, the fiber sizing agent solution of the present invention preferably has a high concentration during distribution and a low concentration during production of the fiber bundle. That is, by distributing the fiber at a high concentration, transportation costs, storage costs, etc. can be reduced, and by processing the fibers at a low concentration, it is possible to produce a fiber bundle that achieves both excellent bundling and opening properties.
The concentration (weight ratio of components other than the solvent) of the fiber sizing agent solution during circulation is preferably 30 to 80% by weight, more preferably 40 to 70% by weight, from the viewpoint of storage stability and the like.
The concentration of the fiber sizing agent solution during the production of the fiber bundle is preferably 0.5 to 15% by weight from the viewpoint that the adhesion amount of the fiber sizing agent can be made appropriate during the production of the fiber bundle. More preferably 1 to 10% by weight.

The method for producing the fiber sizing agent solution of the present invention is not particularly limited, but for example, a solvent is added to the fiber sizing agent composition of the present invention to dissolve or emulsify the fiber sizing agent composition in the solvent. There is a method to make
The temperature at which the fiber sizing agent composition is dissolved or emulsified and dispersed in the solvent is preferably 20 to 90°C, more preferably 40 to 90°C, from the viewpoint of ease of mixing. The time for dissolving or emulsifying and dispersing the fiber sizing agent composition in the solvent is preferably 1 to 20 hours, more preferably 1 to 10 hours.
When dissolving or emulsifying and dispersing the fiber sizing agent composition in a solvent, known mixing devices, dissolving devices and emulsifying and dispersing devices can be used. and three-stage paddle, etc.), Nauta Mixer [manufactured by Hosokawa Micron Corporation, etc.], ribbon mixer, conical blender, mortar mixer, universal mixer {universal mixer "5DM-L" [manufactured by Sanei Seisakusho Co., Ltd.], etc. }, a Henschel mixer [Nippon Coke Kogyo Co., Ltd.], an autoclave, and the like can be used.

Fibers to which the fiber sizing agent composition or fiber sizing agent solution of the present invention can be applied include inorganic fibers (carbon fibers, glass fibers, ceramic fibers, metal fibers, mineral fibers, slag fibers, etc.) and organic fibers (aramid fibers, etc.). etc.). Among these, carbon fiber is preferable from the viewpoint of the strength of the molded article of the composite material using the fiber sizing agent composition and the fiber.

Methods for treating fibers with the fiber sizing agent composition or the fiber sizing agent solution of the present invention include a spray method and a dipping method. The amount of the fiber sizing agent composition deposited on the fibers is preferably 0.05 to 5% by weight, more preferably 0.2 to 2.5% by weight, based on the weight of the fibers, from the viewpoint of sizing properties. % by weight.

The fiber bundle obtained by treating the fiber with the fiber sizing agent composition or the fiber sizing agent solution of the present invention may be processed into a fiber product. Textile products include woven fabrics, knitted fabrics, non-woven fabrics (such as felt, mats and papers), chopped and milled fibers, and the like.

The fiber bundle and/or fiber product obtained by treatment with the fiber sizing agent composition or the fiber sizing agent solution of the present invention may be combined with a matrix resin to form a composite material.
Matrix resins include thermoplastic resins (polypropylene, polyamide, polyethylene terephthalate, polycarbonate, polyphenylene sulfide, etc.), thermosetting resins [the same as epoxy resins, unsaturated polyester resins and vinyl ester resins, and phenolic resins (Patent No. 3723462, etc.) and the like].

In the composite material, the weight ratio of the matrix resin to the fiber bundle (matrix resin/fiber bundle) is preferably 10/90 to 90/10, more preferably 20, from the viewpoint of the strength of the molded article of the composite material. /80 to 70/30, particularly preferably 30/70 to 60/40. The composite material may contain a catalyst.

The composite material is a matrix resin that has been thermally melted (preferred melting temperature: 60 to 350 ° C.) or diluted with a solvent (acetone, methyl ethyl ketone, methyl isobutyl ketone, toluene, xylene, ethyl acetate, etc.), fiber bundles and / Alternatively, it can be produced by impregnating a textile product. If a solvent is used, it is preferred to dry the prepreg to remove the solvent.

When the matrix resin constituting the composite material is a thermoplastic resin, the prepreg can be heat-molded and solidified at room temperature to form a molded body.
When the matrix resin constituting the composite material is a thermosetting resin, the prepreg can be heat-molded and cured to form a molded body.
These resins do not need to be completely cured, but are preferably cured to such an extent that the molded article can maintain its shape. After molding, it may be further heated for complete curing.
The method of thermoforming is not particularly limited, and known methods include, for example, a filament winding molding method (a method of winding while applying tension to a rotating mandrel and thermoforming), a press molding method (a method of laminating prepreg sheets and thermoforming ), an autoclave method (a method in which a prepreg sheet is pressed against a mold and heat-molded), and a method in which chopped fibers or milled fibers are mixed with a matrix resin and injection-molded.

EXAMPLES The present invention will be further described below with reference to Examples and Comparative Examples, but the present invention is not limited to these. Hereinafter, parts are by weight unless otherwise specified.

In this example, the Mn, the epoxy equivalent, and the number of epoxy functional groups per epoxy resin molecule were measured by the following methods.

<Method for measuring Mn of epoxy resin>
The Mn of the epoxy resin was measured at 40° C. by GPC using the following standard substances.
The measurement conditions of GPC are as follows.
(GPC measurement conditions)
Model: Alliance (liquid chromatograph manufactured by Nippon Waters Co., Ltd.)
Column: Guard column Super HL
+TSK gel Super H4000
+ TSK gel Super H3000
+ TSK gel Super H2000
(both manufactured by Tosoh Corporation)
Column temperature: 40°C
Detector: RI (Refractive Index)
Eluent: Tetrahydrofuran Eluent flow rate: 0.6 ml/min Sample concentration: 0.25% by weight
Injection volume: 10 μl
Reference material:
Molecular weight = 228 (Idemitsu Kosan Co., Ltd.; bisphenol A)
Molecular weight = 340 (manufactured by Mitsui Chemicals Fine Co., Ltd.; Epomic R139S)
Molecular weight = 370 (manufactured by Mitsubishi Chemical Corporation; jER828)
Molecular weight = 470 (manufactured by Mitsubishi Chemical Corporation; jER834)
Molecular weight = 900 (manufactured by Mitsubishi Chemical Corporation; jER1001)
Molecular weight = 1200 (manufactured by Mitsubishi Chemical Corporation; jER1002)

<Method for calculating the epoxy equivalent of the epoxy resin>
The epoxy equivalent of the epoxy resin was calculated by the following method.
(1) 0.6 to 0.7 g of a sample was accurately weighed in an Erlenmeyer flask to the nearest 0.1 mg.
(2) Next, 25 mL of a 0.2 mol/L hydrochloride dioxane solution was added, and the mixture was stoppered and stirred at room temperature for 15 minutes using a magnetic stirrer for reaction.
(3) After completion of the reaction, the inner wall and stopper of the flask were washed with 20 ml of methyl alcohol. Next, about 10 drops of cresol red indicator were added and titrated with a 0.1 mol/L potassium hydroxide standard solution.
The end point of the titration is the point at which the color changes from pink to yellow once, and then changes to purple when about one drop of 0.1 mol/L potassium hydroxide standard solution is added dropwise.
(4) The operations (1) to (3) were performed for two samples, and blanks were also measured at the same time.
(5) The epoxy equivalent was calculated based on the following formula, and the average value of the two measured values was calculated.
Epoxy equivalent (g / eq) = [10000 × {weight of sample (g)}] / [{titration amount of blank (ml)} - {titration amount in (3) (ml)}] × f]
Note that f indicates the titer of a 0.1 mol/l potassium hydroxide standard solution.

<Calculation of number of epoxy functional groups per molecule of epoxy resin (number of functional groups per molecule)>
The number of epoxy functional groups was calculated by the following formula.
[Number of functional groups per molecule]=[Mn of epoxy resin]/[epoxy equivalent of epoxy resin]

<Production Example 1: Production of aromatic epoxy resin (A-1)>
200 parts of bisphenol A and 460 parts of epichlorohydrin were placed in a reactor equipped with an oil-water separator equipped with a stirrer, a thermometer, a nitrogen inlet tube, a dropping device, and a cooling tube, and dissolved by heating to 60° C. under a nitrogen atmosphere. Next, 10 parts of 96% solid potassium hydroxide was added to this solution and reacted at 60° C. for 2 hours. Next, while maintaining the temperature in the reaction system at 60° C., the pressure is gradually reduced to azeotrope epichlorohydrin and water. It was brought back to reflux. While maintaining this state, 60 parts of 99% sodium hydroxide was added dropwise over 4 hours. During this time, the inside of the system was maintained at 60-62° C., 100-120 mmHg, and 0.3-0.8% moisture content. After completion of the dropwise addition, the mixture was maintained under reflux at 60° C. and 100 mmHg for 30 minutes. Thereafter, while removing the refluxed epichlorohydrin from the system, the temperature and the degree of pressure reduction in the system were gradually increased, and epichlorohydrin was evaporated and recovered until the final temperature reached 150° C. and 5 mmHg. Thereafter, the system was returned to normal pressure, and 300 parts of toluene was added to dissolve the crude resin. 500 parts of water was added to this solution to separate and remove by-product salt. After that, washing was performed several times with 300 parts of water, and this was repeated until the washing water became neutral. Toluene was removed from this solution by heating to 150° C. under a reduced pressure of 5 mmHg to obtain a liquid epoxy resin. The resulting epoxy resin was an aromatic epoxy resin (A-1) having an epoxy equivalent of 179 g/eq, an Mn of 344, and a functional group number of 1.92 per molecule.

<Production Example 2: Production of aromatic epoxy resin (A-2)>
200 parts of bisphenol A, 445 parts of epichlorohydrin and 300 parts of toluene were placed in the same apparatus as in Production Example 1, and dissolved by heating to 60° C. under a nitrogen atmosphere. 10 parts of 96% solid potassium hydroxide was added to this solution and reacted at 80° C. for 2 hours. Next, 60 parts of 99% sodium hydroxide was added dropwise over 3 hours at 85 to 86° C. under normal pressure. At this time, an azeotropic mixture of toluene and water was refluxed, the water in the lower layer was removed from the outside of the system in an oil-water separator, the toluene in the upper layer was returned to the system, and the system was maintained under reflux at 86°C for 30 minutes. After that, 400 parts of toluene and 500 parts of water were added to separate and remove by-product salt. This solution was washed several times with 300 parts of water until the wash water was neutral. From this solution, toluene was removed by heating to 150° C. under a reduced pressure of 5 mmHg to obtain an aromatic epoxy resin (A-2) having an epoxy equivalent of 192 g/eq, an Mn of 370, and a functional group per molecule of 1.93. .

<Production Example 3: Production of aromatic epoxy resin (A-3)>
In Production Example 2, the same operation as in Production Example 2 was performed except that 445 parts of epichlorohydrin was changed to 375 parts, and an aromatic epoxy resin (A- 3) was obtained.

<Production Example 4: Production of aromatic epoxy resin (A-4)>
In Production Example 2, the same operation as in Production Example 3 was performed except that 445 parts of epichlorohydrin was changed to 114 parts, and an aromatic epoxy resin (A- 4) was obtained.

<Production Example 5: Production of aromatic epoxy resin (A-5)>
In Production Example 1, the same operation as in Production Example 1 was performed except that 460 parts of epichlorohydrin was changed to 440 parts, and an aromatic epoxy resin (A -5) was obtained.

<Comparative Production Example 1: Production of Comparative Aromatic Epoxy Resin (Comparison A-1)>
In Production Example 1, after dropping 60 parts of 99% sodium hydroxide, 60 ° C., 100 mm
An aromatic epoxy resin having an epoxy equivalent of 177 g/eq, an Mn of 348, and a functional group per molecule of 1.97 was prepared in the same manner as in Production Example 1, except that the Hg reflux was maintained for 3 hours instead of 30 minutes. (Ratio A-1) was obtained.

<Comparative Production Example 2: Production of Comparative Aromatic Epoxy Resin (Comparison A-2)>
In Production Example 1, the procedure was carried out in the same manner as in Production Example 1, except that 20 parts of 99% sodium hydroxide was dropped over 1 hour instead of dropping 60 parts of 99% sodium hydroxide over 4 hours. An aromatic epoxy resin (ratio A-2) having an eq, Mn of 333 and a number of functional groups per molecule of 1.76 was obtained.

<Examples 1 to 7, Comparative Examples 1 to 2>
Aromatic epoxy resin and nonionic surfactant (B-1) [propylene oxide ethylene oxide adduct of styrenated phenol [trade name “Soprophor 796/P”, Solvay Nicca Co., Ltd.] is uniformly dissolved in a universal mixer [universal mixing stirrer, manufactured by Sanei Seisakusho Co., Ltd.] for 30 minutes while controlling the temperature at 60 ° C., and then water is added for 6 hours. Fiber sizing agent solutions (Y-1) to (Y-7) of Examples having a solid content concentration of 40% by weight and fiber sizing agent solutions (Y'-1) to (Y'-) of Comparative Examples were added dropwise. 2) was obtained in an amount of 250 parts each.

Materials used in Examples and Comparative Examples are as follows.
<Aromatic epoxy resin (A)>
(A-1): Aromatic epoxy resin produced in Production Example 1 (A-2): Aromatic epoxy resin produced in Production Example 2 (A-3): Aromatic epoxy resin produced in Production Example 3 (A -4): Aromatic epoxy resin produced in Production Example 4 (A-5): Aromatic epoxy resin produced in Production Example 5 <Comparative aromatic epoxy resin>
(Ratio A-1): Aromatic epoxy resin produced in Comparative Production Example 1 (Ratio A-2): Aromatic epoxy resin produced in Comparative Production Example 2 <Nonionic surfactant (B)>
(B-1): Propylene oxide ethylene oxide adduct of styrenated phenol [manufactured by Solvay Nikka Co., Ltd., trade name: "Soprophor 796/P", HLB = 13.7]

<Evaluation test>
Using the fiber sizing agent solutions (Y-1) to (Y-7) and (Y'-1) to (Y'-2) obtained in Examples 1 to 7 and Comparative Examples 1 and 2, the following method A carbon fiber bundle was prepared by and evaluated for interfacial shear strength and fluffing. Table 1 shows the results.

<Production of carbon fiber bundle for evaluation test>
Water was added to the fiber sizing agent solution of each example so that the solid content concentration was 1.5% by weight to form a dispersion, and untreated carbon fibers (24,000 filaments) were immersed in the fiber sizing agent solution. impregnated with a dispersion of the agent composition. After that, the carbon fibers were taken out from the dispersion of the fiber sizing agent composition and dried with hot air at 180° C. for 3 minutes to obtain a carbon fiber bundle. The carbon fiber bundles were produced such that the amount of solids contained in the dispersion of the fiber sizing agent composition adhering to the fibers (percentage based on the weight of the carbon fibers before immersion) was 1.5% by weight. . The carbon fiber bundle was subjected to interfacial shear strength and fluffing evaluation tests.

<Evaluation test of interfacial shear strength>
Interfacial shear strength was evaluated by microdroplet test.
A single yarn was taken out from the carbon fiber bundle and set on a sample holder. Epoxy resin [jER828 (product name) manufactured by Mitsubishi Chemical Corporation] is used as the matrix resin, and 100 parts by mass of the resin and 45 masses of a curing agent [amine-based curing agent Jeffamine T-403 (product name) manufactured by Huntsman]. were mixed, coated on a carbon fiber single yarn to form a drop, and cured at 80° C. for 180 minutes to obtain a sample for measurement. For the measurement, a composite material interface property evaluation device HM410 [manufactured by Toei Sangyo Co., Ltd.] was used, and the maximum pull-out load F was measured when the drop was pulled out from the single yarn while running at a speed of 0.12 mm/min. The interfacial shear strength τ was calculated from the following formula, and the interfacial shear strength between the single yarn and the matrix resin was evaluated. The larger the numerical value of the interfacial shear strength, the better the adhesiveness between the fiber and the matrix resin. The interfacial shear strength is preferably 55 MPa or more.
Interfacial shear strength τ (unit: MPa) = F/πdl
(F: Maximum pull-out load d: Single yarn diameter l: Particle diameter in the pull-out direction of the drop)

<Fluff evaluation test>
(1) Description of Apparatus for Evaluation As shown in FIG. The carbon fiber bundles 4 were arranged parallel to each other with a horizontal interval of 50 mm, and the carbon fiber bundles 4 passed through the stainless steel rods 1A, 1B, 1C, 1D and 1E in a zigzag manner while being in contact with them. The horizontal direction is the direction indicated by the arrows indicated by XX' in the drawing, and is the direction parallel to the horizontal plane HL.
A straight line connecting the centers of the stainless steel rods 1A, 1C and 1E through which the carbon fiber bundles 4 pass the first, third and fifth, and the stainless steel rod 1B and the stainless steel rod 1B through which the carbon fiber bundles 4 pass the second and fourth. A straight line connecting the centers of 1D was arranged so as to be parallel to the horizontal plane. Before and after the passage of the second to fourth stainless steel rods 1B and 1D, the straight line in the traveling direction of the carbon fiber bundles before passing and the straight line in the traveling direction of the carbon fiber bundles after passing are 120 degrees. (for example, a straight line parallel to the traveling direction of the carbon fiber bundle passing between the first stainless steel rod 1A and the second stainless steel rod 1B, and the second stainless steel rods 1B and 3 The angle formed by the traveling direction of the carbon fiber bundle passing between the second stainless steel rod 1C and a straight line parallel thereto forms an angle of 120 degrees).
The unwinding roll 2 and the winding roll 3 were set to rotate in the direction of the arrow drawn near each roll.
(2) Measurement of fluff weight The carbon fiber bundle 4 is zigzag between the stainless steel rods 1A, 1B, 1C, 1D, and 1E, and after passing through the stainless steel rod 1E, the area immediately before being wound on the winding roll 3 (winding In the region 5A) 10 cm upstream from the winding start point 3A of the take-up roll 3, the carbon fiber bundle 4 is made of two square urethane foam sheets of 10 cm × 10 cm under a load of 1 kg, and the thickness of the fiber bundle is It was sandwiched from the direction (vertical direction in the figure). In this example, since the carbon fiber bundle is conveyed from the unwinding roll 2 to the winding roll 3, the "upstream side" means the upstream in the conveying direction, that is, the unwinding roll 2 side.
The unit fiber bundle 4 is wound while being sandwiched between urethane foams. The unwinding tension is set to 9.8 N (1 kgf), and the carbon fiber bundle 4 is spun at a speed of 1 m/min for 5 minutes. It was wound up from the unwinding roll 2 to the winding roll 3. During this time, the weight of fluff adhering to the two urethane foam sheets was measured. A smaller numerical value indicates that fluffing can be suppressed. The weight of fluff is preferably 10 mg or less.

As shown in Table 1, it was found that the use of the fiber sizing agent solutions of Examples can suppress fluffing and improve the interfacial shear strength. From this, it can be seen that the present invention can provide a fiber sizing agent that suppresses fluffing and has excellent adhesiveness between the fibers and the matrix resin.

1A, 1B, 1C, 1D, 1E... Stainless steel rod 2... Unwinding roll 3... Winding roll 3A... Winding start point 4... Carbon fiber bundle 5A... Area 10 cm upstream from 3A HL... Horizontal plane

Claims (3)

A fiber sizing agent composition containing an aromatic epoxy resin (A) and a nonionic surfactant (B),
The number of epoxy functional groups per molecule of the aromatic epoxy resin (A) is 1.80 to 1.95, and the aromatic epoxy resin (A) is a bisphenol type epoxy resin having a number average molecular weight of 330 to 1200. A sizing agent composition for fibers containing 50% by weight or more based on the total weight of the group epoxy resin (A). The fiber sizing agent according to claim 1, wherein the ratio (W2/W1) of the weight W2 of the nonionic surfactant (B) to the weight W1 of the aromatic epoxy resin (A) is 5/95 to 50/50. Composition. A fiber sizing agent solution obtained by dissolving or dispersing the fiber sizing agent composition according to claim 1 or 2 in a solvent containing at least one selected from the group consisting of water and organic solvents.

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