JP6019942B2 - Resin composition, fiber sizing agent and molded product - Google Patents

Description

  The present invention relates to a resin composition that can be used, for example, as a fiber sizing agent. The present invention also relates to a molded product that can be used in various fields including parts of automobiles and aircraft, and parts of household electrical appliances.

As automobile members, aircraft members, and the like that are required to have high strength and excellent durability, fiber reinforced plastics including, for example, a matrix resin such as a vinyl ester resin and glass fibers or carbon fibers have been used.
As the carbon fiber or glass fiber used for the fiber reinforced plastic, usually, a fiber material that is generally bundled to about several thousand to several tens of thousands by a fiber sizing agent is often used from the viewpoint of imparting high strength.

  Examples of the fiber sizing agent include an epoxy resin and an epoxy resin containing a predetermined amount of a bisphenol-based polyether compound obtained by condensing an alkylene oxide adduct of a predetermined bisphenol compound and polyethylene glycol with a polyisocyanate compound. A fiber sizing agent comprising a resin water dispersion is known (for example, see Patent Document 1).

  However, a fiber sizing agent comprising an epoxy resin aqueous dispersion as described in Patent Document 1 is sufficient in terms of sizing properties such as fiber unwinding, fluffing, and yarn breakage during fiber winding and weaving processes. As a result, there is a problem that productivity of the bundled fibers is remarkably lowered.

  In addition, it is not sufficient for the fiber sizing agent to simply have excellent adhesion and wettability to the fiber, and even when stress is applied to the finally bundled carbon fiber bundle, it may cause thread breakage or the like. It is required that the stress can be relieved so that there is not. This is a crucial difference between the fiber sizing agent and the adhesive. Therefore, when a conventionally known adhesive is used instead of the fiber sizing agent, it may seem that the fiber sizing property is excellent at first glance, but the fiber bundle is stressed during the fiber winding or weaving process. When added, fiber breakage, fluffing, and yarn breakage may occur, resulting in a significant reduction in the productivity of the focused fibers.

  Further, even if the fiber sizing agent having excellent sizing property is used, if the compatibility with the matrix resin is not sufficient, the mechanical strength of the finally obtained fiber reinforced plastic, specifically, the bending strength is remarkable. Since it may cause a decrease, it may not be used for applications requiring high strength.

  Thus, there has not yet been found a fiber sizing agent that can achieve both improvement in sizing properties of carbon fibers and the like and improvement in mechanical strength of a molding material such as fiber reinforced plastic obtained.

JP 2000-178410 A

The problem to be solved by the present invention is a fiber sizing agent that is excellent in sizing properties of glass fibers and carbon fibers, and that can be used in the production of molded articles having excellent strength including tensile strength, and the fiber sizing agent. It is providing the resin composition which can be used for manufacture of this.
Moreover, this invention is providing the molded article excellent in intensity | strength including tensile strength.

  As a result of studies to solve the above problems, the present inventors have found that the above problems can be solved if the resin composition includes an acrylic resin (A) having a polyoxyalkylene structure and a glycidyl group.

  That is, the present invention relates to a resin composition containing an acrylic resin (A) having a polyoxyalkylene structure and a glycidyl group and an aqueous medium (B), and a fiber sizing agent containing the same. .

If it is the resin composition of this invention, since it is excellent in the bundling property of glass fiber or carbon fiber, it can be used exclusively for the fiber bundling agent of glass fiber or carbon fiber.
In addition, a molded article containing fibers and matrix resin focused using the fiber sizing agent is a machine that does not pull cracks or the like even when it is pulled, bent, or subjected to a strong impact. It is possible to manufacture molded products such as fiber reinforced plastics with sufficient strength. Such molded articles can be used in various applications including, for example, automobile and aircraft members, home appliance parts, and wind power generation members.

The resin composition of the present invention is characterized by containing an acrylic resin (A) having a polyoxyalkylene structure and a glycidyl group, an aqueous medium (B), and other components as required.
As said acrylic resin (A), what has a combination of a polyoxyalkylene structure and a glycidyl group is used.
Here, when an acrylic resin having no polyoxyalkylene structure is used in place of the acrylic resin (A), the storage stability of the resin composition is lowered, and the convergence of glass fibers and carbon fibers is lowered. In addition, the strength of the molded product finally obtained may be reduced.
Moreover, when the acrylic resin which does not have a glycidyl group is used instead of the said acrylic resin (A), the fall of the intensity | strength of the molded article finally obtained, etc. may be caused.
The polyoxyalkylene structure has an oxyethylene structure in order to achieve both good water dispersion stability of the acrylic resin (A) and excellent convergence and high strength of the molded product. Is preferred.
Examples of the polyoxyalkylene structure include a polyoxyethylene structure, a polyoxyethylene-polyoxypropylene structure composed of a copolymer composed of polyoxyethylene and polyoxypropylene, and a polyoxyethylene and polyoxybutylene. A polyoxyethylene-polyoxybutylene structure composed of a copolymer, a polyoxyethylene-polyoxytetramethylene structure composed of a copolymer composed of polyoxyethylene and polyoxytetramethylene, Examples include a structure in which a hydroxyl group that may exist is sealed with an alkyl group or the like.
The polyoxyalkylene structure may be a random structure composed of an oxyethylene unit and another oxyalkylene unit. However, the water dispersion stability of the acrylic resin (A) and the excellent convergence are A block structure composed of polyoxyethylene and other polyoxyalkylenes is preferable for achieving both high strength of the molded product.
It is preferable that the said polyoxyalkylene structure exists in the range of 5 mass%-40 mass% with respect to the whole quantity of the said acrylic resin (A). In addition, the polyoxyalkylene structure is suitable for achieving both good water dispersion stability of the acrylic resin (A) and excellent convergence and high strength of a molded product. On the other hand, it is preferable to have a polyoxyethylene structure in the range of 75% by mass to 100% by mass.
In addition, the glycidyl group of the acrylic resin (A) is 200 g / equivalent to the entire acrylic resin (A) in order to achieve both excellent sizing properties such as carbon fibers and high strength of the molded product. It is preferably present in the range of ˜1500 g / equivalent.
As said acrylic resin (A), in order to obtain the molded article provided with the further outstanding intensity | strength, it is preferable to use what has the weight average molecular weight of the range of 5,000-150,000. In addition, the said weight average molecular weight points out the value measured using gel permeation chromatography (GPC).
The acrylic resin (A) is, for example, a monomer having a polymerizable unsaturated double bond containing a (meth) acryl monomer having a polyoxyalkylene structure and a (meth) acryl monomer having a glycidyl group. The mixture (a) can be produced by radical polymerization. In the present invention, the notation “(meth) acryl” represents one or both of “acryl” and “methacryl”.
Examples of the (meth) acrylic monomer having a polyoxyalkylene structure include those obtained by esterifying (meth) acrylic acid or (meth) acrylic acid ester with polyoxyalkylene glycol, ) Acrylic acid or (meth) acrylic acid ester and polyoxyalkylene monoalkyl ether obtained by esterification can be used.
Specifically, as the (meth) acrylic monomer having the polyoxyalkylene structure, methoxy polyoxyethylene glycol (meth) acrylate, methoxy (polyoxyethylene-polyoxypropylene) glycol (meth) acrylate, methoxy ( Polyoxyethylene-polyoxytetramethylene) glycol (meth) acrylate and the like can be used. Above all, the use of methoxypolyoxyethylene glycol (meth) acrylate can achieve both good water dispersion stability of acrylic resin (A) and excellent convergence and high strength of molded products. It is preferable when obtaining a resin composition.
The (meth) acrylic monomer having a polyoxyalkylene structure is used in a range of 10 to 40% by mass with respect to the total amount of the monomer mixture (a). Resin composition that introduces the structure into the acrylic resin (A) and, as a result, achieves both good water dispersion stability of the acrylic resin (A) and excellent convergence and high strength of the molded product It is preferable when obtaining a thing.
Moreover, as the (meth) acryl monomer having the glycidyl group, for example, glycidyl (meth) acrylate can be used.
The (meth) acrylic monomer having a glycidyl group is used in the range of 10 to 70% by mass with respect to the total amount of the monomer mixture (a). Introducing into (A), as a result, it is preferable to obtain a resin composition capable of imparting excellent convergence and high strength of the molded product.
The (meth) acrylic monomer having a polyoxyalkylene structure and the (meth) acrylic monomer having a glycidyl group are in a mass ratio [(meth) acrylic monomer having a polyoxyalkylene structure / When the (meth) acrylic monomer having a glycidyl group] is in a range of 0.1 to 4, the water dispersion stability of the acrylic resin (A) is excellent, and excellent focusing properties and molded products are used. This is preferable for achieving both high strength.
The monomer mixture (a) that can be used for the production of the acrylic resin (A) includes the (meth) acrylic monomer having the polyoxyalkylene structure and the (meth) acrylic monomer having a glycidyl group. In addition, other monomers having a polymerizable unsaturated double bond can be used as necessary.
As said other monomer which has a polymerizable unsaturated double bond, (meth) acrylic-acid alkylester can be used, for example.
Examples of the (meth) acrylic acid alkyl ester include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, cyclohexyl (meth) acrylate, ( It is possible to use 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, or the like. Especially, it is preferable to use the (meth) acrylic-acid alkylester which has a C1-C8 alkyl group from a viewpoint of obtaining the molded article provided with much more excellent convergence and intensity | strength.
The (meth) acrylic acid ester is preferably used in the range of 0% by mass to 80% by mass with respect to the total amount of the monomer mixture (a), and is used in the range of 2% by mass to 40% by mass. More preferably.
Moreover, as said other monomer, vinyl monomers, such as styrene, alpha-methyl styrene, paramethyl styrene, chloromethyl styrene, vinyl acetate, can be used, for example.
Examples of the other monomers include 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, isobornyl (meth) acrylate, (meth ) Benzyl acrylate, 2-hydroxybutyl (meth) acrylate, glycidyl (meth) acrylate, (meth) acrylic acid, diethylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylic acid, Di (meth) acrylic acid-1,6-hexanediol, trimethylolpropane tri (meth) acrylate, glycerin di (meth) acrylate, and the like can be used.

  The said acrylic resin (A) can be manufactured by heating the said monomer mixture (a) at the temperature of about 60 to 140 degreeC in the organic solvent, for example, and carrying out radical polymerization.

  Examples of the organic solvent include aromatic solvents such as toluene and xylene, alicyclic solvents such as cyclohexanone, ester solvents such as normal butyl acetate and ethyl acetate, isobutanol, and normal butanol. Cellosolves such as isopropyl alcohol, sorbitol and propylene glycol monomethyl ether acetate, ketones such as methyl ethyl ketone and methyl isobutyl ketone, and the like can be used.

  Moreover, when radical-polymerizing the said monomer mixture (a), an organic peroxide can be used as needed.

  Examples of the organic peroxide include peroxides having a carbon atom in the skeleton, such as ketone peroxide, peroxyketal, hydroperoxide, dialkyl peroxide, diacyl peroxide, peroxyester, peroxydicarbonate, alkyl peroxide. An oxycarbonate, an azobis catalyst, a persulfuric acid compound, or the like can be used.

  The acrylic resin (A) obtained by the above method may contain no solvent, but contains the organic solvent as a solvent or contains an aqueous medium (B) as a solvent. Also good.

  Examples of the method for producing the resin composition of the present invention by mixing the acrylic resin (A) with the aqueous medium (B) include a method using a phase inversion emulsification method.

Examples of the aqueous medium (B) include water, organic solvents miscible with water, and mixtures thereof. Examples of the organic solvent miscible with water include alcohols such as methanol, ethanol, n- and isopropanol; ketones such as acetone and methyl ethyl ketone; polyalkylene glycols such as ethylene glycol, diethylene glycol and propylene glycol; Alkyl ethers; lactams such as N-methyl-2-pyrrolidone, and the like. In the present invention, only water may be used, a mixture of water and an organic solvent miscible with water may be used, or only an organic solvent miscible with water may be used. From the viewpoint of safety and load on the environment, water alone or a mixture of water and an organic solvent miscible with water is preferable, and only water is particularly preferable.
The resin composition of the present invention contains the acrylic resin (A) in the range of 2% by mass to 80% by mass with respect to the total amount of the resin composition from the viewpoint of imparting good coating workability and the like. Is preferably used, and more preferably in the range of 5 to 70% by mass.
Moreover, the said resin composition contains the said aqueous medium (B) in 15 mass%-95 mass% with respect to the whole quantity of the said resin composition from a viewpoint of providing favorable coating workability | operativity etc. Is preferably used, and more preferably in the range of 25% by mass to 90% by mass.

  The resin composition may be added with a curing agent, a curing catalyst, a lubricant, a filler, a thixotropic agent, a tackifier, a wax, a thermal stabilizer, a light-resistant stabilizer, a fluorescent whitening agent, a foaming agent, and the like as necessary. Agent, pH adjuster, leveling agent, anti-gelling agent, dispersion stabilizer, antioxidant, radical scavenger, heat resistance imparting agent, inorganic filler, organic filler, plasticizer, reinforcing agent, catalyst, antibacterial agent, Anti-mold agent, anti-rust agent, thermoplastic resin, thermosetting resin, pigment, dye, conductivity imparting agent, anti-static agent, moisture permeability improver, water repellent, oil repellent, hollow foam, crystal water-containing compound , Flame retardants, water absorbents, moisture absorbents, deodorants, foam stabilizers, antifoaming agents, antifungal agents, antiseptics, algaeproofing agents, pigment dispersants, antiblocking agents, hydrolysis inhibitors, pigments be able to.

  In addition, the resin composition is an emulsion such as vinyl acetate, ethylene vinyl acetate, acrylic, epoxy, urethane, polyester, polyamide, etc., as necessary, within a range not impairing the effects of the present invention. They can be used in combination with latexes such as styrene / butadiene, acrylonitrile / butadiene, and acryl / butadiene, and water-soluble resins such as poval and cellulose.

  The resin composition of the present invention obtained by the above method can be used exclusively as a fiber sizing agent for carbon fibers or glass fibers.

  As the carbon fiber that can be treated with the fiber sizing agent, polyacrylonitrile-based or pitch-based carbon fibers can be generally used. Especially, as said carbon fiber, it is preferable to use a polyacrylonitrile-type carbon fiber from a viewpoint which provides the outstanding intensity | strength.

  Moreover, as said carbon fiber, it is preferable to use what has a single yarn diameter of about 0.5 micrometer-20 micrometers from a viewpoint which provides the further outstanding intensity | strength etc., and it is preferable to use a thing of 2 micrometers-10 micrometers. More preferred.

As the carbon fiber, for example, twisted yarn, spun yarn, spun yarn, non-woven fabric can be used. Further, as the carbon fiber, filaments, yarns, rovings, strands, chopped strands, felts, needle punches, cloths, roving cloths, milled fibers, and the like can be used.
Moreover, as said glass fiber, the glass fiber formed using alkali-containing glass, low alkali glass, an alkali free glass etc. can be used.

  Examples of a method for bundling the carbon fiber or glass fiber using the fiber sizing agent and forming a film made of the acrylic resin (A) contained in the fiber sizing agent on the surface of the fiber bundle include, for example, Examples of the method include forming the fiber sizing agent by applying the fiber sizing agent uniformly on the surface of the fiber using a kiss coater method, a roller method, a dipping method, a spraying method, a brush, and the like, and then drying at room temperature or heating. . The aqueous medium (B) contained in the fiber sizing agent is preferably heated and dried using a heating roller, hot air, a hot plate or the like after the application.

  The amount of the coating formed on the surface of the fiber material is preferably approximately 0.1% by mass to 3% by mass with respect to the total mass of the bundle of fibers that have been focused and subjected to surface treatment. It is more preferable that it is 1 mass%-1.5 mass%.

  The focused and surface-treated carbon fiber or glass fiber obtained by the above method is used as a molding material for producing a high-strength molded product by using it in combination with a matrix resin (C) described later. Can be used.

  In particular, when the carbon fiber surface-treated with the carbon fiber sizing agent of the present invention is used in combination with the matrix resin (C) to form a molded article, the interface between the carbon fiber and the matrix resin (C). Therefore, the strength of the molded product can be improved.

  As said matrix resin (C), a thermosetting resin (C1) or a thermoplastic resin (C2) can be used, for example. As the thermosetting resin (C1), phenol resin, polyimide resin, bismaleimide resin, unsaturated polyester resin, epoxy resin or the like can be used. Examples of the thermoplastic resin (C2) include saturated polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polypropylene, polystyrene, polycarbonate, polyphenylene sulfide, polyphenylene oxide, 6-nylon, 6,6-nylon, and acrylonitrile-styrene. Polymers, acrylonitrile-butadiene-styrene copolymers, polyacetals, etc. can be used, among which selected from the group consisting of phenol resins, unsaturated polyester resins, epoxy resins, polyester resins, olefin resins, and polyamide resins. It is preferable to use one or more. Specifically, the polyamide is preferably used for polyamide resins such as 6-nylon and 6,6-nylon.

  The bundle of fibers bundled using the fiber sizing agent of the present invention is combined with a matrix resin of epoxy resin, unsaturated polyester resin, 6-nylon, 6,6-nylon, polyphenylene oxide, polybutylene terephthalate, polyolefin resin. It is more preferable to use a high strength molded product.

  Examples of the molding material containing the surface-treated fiber bundle, the matrix resin (C), and a polymerizable monomer, if necessary, include chopped strand melt kneading, prepreg and sheet molding compound. (SMC) etc. are mentioned.

  The prepreg is, for example, a method in which the matrix resin (C) is applied onto a release paper, a surface-treated fiber is placed on the application surface, and press impregnated using a roller or the like as necessary. It is done.

  When producing the prepreg, it is preferable to use an epoxy resin such as a bisphenol A type epoxy resin, a glycidylamine type epoxy resin such as tetraglycidylaminodiphenylmethane, or a novolac type epoxy resin as the matrix resin (C). .

  In addition, the sheet molding compound is, for example, sufficiently impregnated into the surface-treated fiber with a mixture of the matrix resin (C) and a polymerizable unsaturated monomer such as styrene, and then processed into a sheet shape. Can be manufactured. When manufacturing the said sheet molding compound, it is preferable to use unsaturated polyester resin as said matrix resin (C).

  Curing of the molding material proceeds by radical polymerization by heating or light irradiation, for example, under pressure or normal pressure. In such a case, a known thermosetting agent, photocuring agent, or the like can be used in combination.

  Examples of the molding material include those obtained by kneading the thermoplastic resin (C2) and the surface-treated fiber bundle under heating. Such a molding material can be used for secondary processing by, for example, injection molding.

  Since a molded product obtained using the molding material has high strength, it can be used as a carbon fiber reinforced plastic or the like, for example, in an automobile member, an aircraft member, an industrial member, or the like.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples.

[Example 1]
A 4-necked flask equipped with a stirrer, reflux condenser, thermometer and nitrogen blowing tube is charged with 45 parts by mass of methyl ethyl ketone and 30 parts by mass of NK ester M-230G (manufactured by Shin-Nakamura Chemical Co., Ltd., methoxypolyethylene glycol methacrylate) 80 The temperature was raised to ° C.
Subsequently, 50 parts by mass of glycidyl methacrylate, 10 parts by mass of styrene, 10 parts by mass of n-butyl methacrylate, 15 parts by mass of methyl ethyl ketone, V-59 (a catalyst manufactured by Wako Pure Chemical Industries, Ltd., 2,2′-azobis (2 -Methylbutyronitrile) A dissolved mixture of 1.6 parts by mass was dropped over 2 hours, and the reaction was carried out in the range of 80 ° C to 85 ° C.

  Then, after hold | maintaining for 120 minutes at 80 degreeC, the temperature of the reaction container was lowered | hung to 70 degreeC, 200 mass parts of ion-exchange water was added, and water dispersion was performed.

  Then, after removing the solvent under reduced pressure at 60 ° C. (0.080 to 0.095 MPa) over about 60 minutes, cooling, and adjusting the nonvolatile content using ion-exchanged water, vinyl having a weight average molecular weight of 40,000 is obtained. A carbon fiber sizing agent (I) [nonvolatile content: 23 wt%] comprising a resin composition containing a polymer was obtained.

[Example 2]
The amount of glycidyl methacrylate used was changed from 50 parts by weight to 8 parts by weight, the amount of styrene used was changed from 10 parts by weight to 20 parts by weight, and acrylic acid 2 instead of 10 parts by weight of n-butyl methacrylate. -Carbon fiber sizing agent (II) comprising a resin composition containing a vinyl polymer having a weight average molecular weight of 45,000 in the same manner as in Example 1 except that 42 parts by mass of ethylhexyl was used. % By weight).

Example 3
The amount of glycidyl methacrylate used is changed from 50 parts by weight to 75 parts by weight, the amount of styrene used is changed from 10 parts by weight to 0 parts by weight, and the amount of n-butyl methacrylate used is changed from 10 parts by weight to 5 parts by weight. Example 1 except that the amount of NK ester M-230G (manufactured by Shin-Nakamura Chemical Co., Ltd., methoxypolyethylene glycol methacrylate) was changed from 30 parts by weight to 20 parts by weight By this method, a carbon fiber sizing agent (III) [nonvolatile content: 23% by weight] comprising a resin composition containing a vinyl polymer having a weight average molecular weight of 25,000 was obtained.

Example 4
The amount of glycidyl methacrylate used was changed from 50 parts by weight to 40 parts by weight, the amount of styrene used was changed from 10 parts by weight to 5 parts by weight, and NK ester M-230G (manufactured by Shin-Nakamura Chemical Co., Ltd., It consists of a resin composition containing a vinyl polymer having a weight average molecular weight of 35,000 in the same manner as in Example 1 except that the amount of methoxypolyethylene glycol methacrylate) was changed from 30 parts by mass to 45 parts by mass. Carbon fiber sizing agent (IV) [non-volatile content: 23% by weight] was obtained.

Example 5
The amount of styrene used was changed from 10 parts by weight to 12 parts by weight, the amount of n-butyl methacrylate used was changed from 10 parts by weight to 30 parts by weight, and NK ester M-230G (Shin Nakamura Chemical Co., Ltd.) The resin composition containing a vinyl polymer having a weight average molecular weight of 66,000 in the same manner as in Example 1 except that the amount of methoxypolyethylene glycol methacrylate) was changed from 30 parts by mass to 8 parts by mass. A carbon fiber sizing agent (V) [non-volatile content: 23% by weight] was obtained.

Example 6
The amount of glycidyl methacrylate used was changed from 50 parts by weight to 60 parts by weight, the amount of styrene used was changed from 10 parts by weight to 5 parts by weight, and the amount of n-butyl methacrylate used was changed from 10 parts by weight to 0 parts by weight. The amount of NK ester M-230G (manufactured by Shin-Nakamura Chemical Co., Ltd., methoxypolyethylene glycol methacrylate) was changed from 30 parts by mass to 20 parts by mass, and 15 parts by mass of n-butyl methacrylate was used. And other than changing the amount of V-59 (a catalyst manufactured by Wako Pure Chemical Industries, Ltd., 2,2′-azobis (2-methylbutyronitrile) from 1.6 parts by mass to 3.2 parts by mass Obtained the carbon fiber sizing agent (VI) [non-volatile content 23 weight%] which consists of a resin composition containing the vinyl polymer of the weight average molecular weight 20,000 by the method similar to Example 1. FIG.

[Comparative Example 1]
The amount of glycidyl methacrylate used is changed from 50 parts by weight to 0 parts by weight, the amount of styrene used is changed from 10 parts by weight to 20 parts by weight, and the amount of n-butyl methacrylate used is changed from 10 parts by weight to 50 parts by weight. A carbon fiber sizing agent (I ′) [non-volatile content: 23% by weight] made of a resin composition containing a vinyl polymer having a weight average molecular weight of 60,000 was obtained in the same manner as in Example 1 except that the amount was changed to parts by mass. Obtained.

[Comparative Example 2]
A 4-necked flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen blowing tube was charged with 45 parts by mass of methyl ethyl ketone and heated to 80 ° C.
Next, 40 parts by mass of glycidyl methacrylate, 20 parts by mass of styrene, 40 parts by mass of n-butyl methacrylate, 15 parts by mass of methyl ethyl ketone, V-59 (a catalyst manufactured by Wako Pure Chemical Industries, Ltd., 2,2′-azobis (2 -Methylbutyronitrile) A dissolved mixture of 1.6 parts by mass was dropped over 2 hours, and the reaction was carried out in the range of 80 ° C to 85 ° C.

  Next, after holding at 80 ° C. for 120 minutes, the temperature of the reaction vessel is lowered to 50 ° C., and 10 parts by mass of Pluronic F-88 (manufactured by ADEKA, polyoxyethylene polyoxypropylene glycol) and 90 parts by mass of ion-exchanged water. Was added, and water dispersion was performed using a homogenizer, and then 100 parts by mass of ion-exchanged water was added.

  Next, after removing the solvent under reduced pressure at 60 ° C. (0.080 to 0.095 MPa) over about 60 minutes, cooling, and adjusting the nonvolatile content using ion-exchanged water, vinyl having a weight average molecular weight of 70,000 is obtained. A carbon fiber sizing agent (II ′) [nonvolatile content: 23% by weight] comprising a resin composition containing a polymer was obtained.

[Measurement of weight average molecular weight]
The weight average molecular weight of the vinyl polymer was measured by the gel permeation chromatography (GPC) method under the following conditions.

Measuring device: High-speed GPC device (“HLC-8220GPC” manufactured by Tosoh Corporation)
Column: The following columns manufactured by Tosoh Corporation were connected in series.

"TSKgel G5000" (7.8 mm ID x 30 cm) x 1 "TSKgel G4000" (7.8 mm ID x 30 cm) x 1 "TSKgel G3000" (7.8 mm ID x 30 cm) x 1 “TSKgel G2000” (7.8 mm ID × 30 cm) × 1 detector: RI (differential refractometer)
Column temperature: 40 ° C
Eluent: Tetrahydrofuran (THF)
Flow rate: 1.0 mL / min Injection amount: 100 μL (tetrahydrofuran solution with a sample concentration of 0.4 mass%)
Standard sample: A calibration curve was prepared using the following monodisperse polystyrene.

(Monodispersed polystyrene)
"TSKgel standard polystyrene A-500" manufactured by Tosoh Corporation
"TSKgel standard polystyrene A-1000" manufactured by Tosoh Corporation
"TSKgel standard polystyrene A-2500" manufactured by Tosoh Corporation
"TSKgel standard polystyrene A-5000" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-1" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-2" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-4" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-10" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-20" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-40" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-80" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-128" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-288" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-550" manufactured by Tosoh Corporation

[Method for evaluating storage stability of carbon fiber sizing agent comprising the resin composition]
The storage stability of the carbon fiber sizing agent comprising the resin composition was evaluated based on the presence or absence of precipitation or the like.
100 ml of the carbon fiber sizing agent was placed in a glass bottle with a capacity of 140 ml and left in an environment of 23 ° C. for 3 months in a sealed state.
After the standing, the carbon fiber sizing agent in the container was visually observed, `` X '' in which precipitation and aggregates were confirmed, `` △ '' in which precipitation was confirmed but could be easily dispersed by stirring. A sample in which no precipitate or aggregate was confirmed was evaluated as “◯”.

[Method for evaluating carbon fiber sizing agent comprising the resin composition]
Bundles of polyacrylonitrile-based carbon fiber (diameter 7μm / 6000) no-size yarn, impregnates the carbon fiber sizing agent obtained above with a dipping method, and squeezes with a roller to adjust the amount of active ingredient attached to 1% by mass Then, heat treatment was performed at 150 ° C. for 30 minutes to obtain a carbon fiber bundle (carbon fiber strand) that was surface-treated (bundled) with the carbon fiber sizing agent.

[Method 1 for evaluating the convergence of carbon fiber 1]
Using a TM-type friction conjugation force tester TM-200 (manufactured by Daiei Kagaku Seiki Co., Ltd.), carbon fiber strands are rubbed 1000 times with a tension of 50 g through three mirror-plated chrome-plated stainless needles arranged in a zigzag (reciprocating motion). The speed of the fluff of the carbon fiber strand was visually determined according to the following criteria.

A: No fluffing was observed as in the case before rubbing.
○: Although some fluff was seen, it was at a level where there was no practical problem.
(Triangle | delta): Fluff was confirmed and some thread breakage was also seen.
X: A lot of fuzz and single yarn breakage were confirmed.

[Method 2 for evaluating the convergence of carbon fiber 2]
A carbon fiber chopped strand was produced by cutting the carbon fiber strand into a length of about 5 mm.

  Fifty carbon fiber chopped strands were extracted and visually observed. Specifically, all 50 carbon fiber chopped strands that did not show loosening or fluffing of carbon fibers were marked with “◎”, and 1 to 5 carbon fiber chopped strands. “○” indicates fuzzing, 6-30 carbon fiber chopped strands, “△” indicates carbon fiber loosening, fuzzing, etc., 31-50 carbon fiber chopped The strands in which the carbon fibers were loosened or fuzzed were evaluated as “x”.

[Evaluation method of mechanical strength (bending strength) of carbon fiber reinforced plastic]
The carbon fiber strand obtained above was compounded with 6-nylon resin pellets (general-purpose injection molding grade) in a biaxial extrusion kneader so that the carbon fiber mass content was 30% by mass, and 3 mmΦ × 3 mm Processed into long compound pellets.

  Compound pellets were injection molded to produce a carbon fiber reinforced plastic consisting of 150 mm flat plates each having a thickness of 3.1 mm. Five bending test plates 10 mm wide x 90 mm long x 3.1 mm thick are cut out from the flat plate, and a three-point bending test (span / thickness ratio = 20, test speed 5 mm / min) is performed according to JIS K7171. The bending strength was measured. The bending strength is preferably approximately 80 MPa or more, and particularly preferably 95 MPa.

[Evaluation method of interlaminar shear strength of carbon fiber reinforced plastic]
Bisphenol A type liquid epoxy resin [Epiclon 850S, manufactured by DIC Corporation] 100 parts by mass, dicyandiamide 4 parts by mass and N- (3,4-dichlorophenyl) -N ', N'-dimethylurea 4 parts by mass were prepared and separated. Apply on pattern paper. The carbon fiber strands obtained above were aligned in one direction at equal intervals on the applied resin film, and then heated to impregnate the epoxy resin to prepare a prepreg having a carbon fiber content of 60% by mass. After the produced prepreg was filled into a mold while being laminated, carbon fiber reinforced plastic was produced by treating under pressure at 150 ° C. for 1 hour and then at 140 ° C. for 4 hours.

  Interlaminar shear strength of the carbon fiber reinforced plastic test plate having a thickness of 2.5 mm and a width of 6.0 mm was measured by a method based on ASTM D-2344. The interlayer shear strength is preferably approximately 90 MPa or more, and particularly preferably 95 MPa or more.

“GMA” in Tables 1 and 2 represents glycidyl methacrylate. “ST” represents styrene. “BA” represents n-butyl acrylate. “BMA” represents n-butyl methacrylate. “EHA” represents 2-ethylhexyl acrylate. “M230G” represents NK ester M-230G (manufactured by Shin-Nakamura Chemical Co., Ltd., methoxypolyethylene glycol methacrylate). “V-59” represents V-59 (a catalyst manufactured by Wako Pure Chemical Industries, Ltd., 2,2′-azobis (2-methylbutyronitrile). “F-88” represents Pluronic F-88 (( Co., Ltd., manufactured by ADEKA, polyoxyethylene polyoxypropylene glycol).
“Weight average molecular weight” represents the weight average molecular weight of the acrylic resin.

Claims (5)

A fiber sizing agent comprising an acrylic resin (A) having a polyoxyalkylene structure and a glycidyl group and an aqueous medium (B) , wherein the acrylic resin (A) has a polyoxyalkylene structure. It is obtained by polymerizing a monomer mixture (a) having a polymerizable unsaturated double bond containing a (meth) acrylic monomer and a (meth) acrylic monomer having a glycidyl group, The (meth) acrylic monomer having the polyoxyalkylene structure is included in the range of 10% by mass to 40% by mass with respect to the total amount of the monomer mixture (a) having the polymerizable unsaturated double bond. A fiber sizing agent characterized by being a thing . Monomer mixture having a polymerizable unsaturated double bond, wherein the acrylic resin (A) contains a (meth) acrylic monomer having a polyoxyalkylene structure and a (meth) acrylic monomer having a glycidyl group. It is obtained by polymerizing (a), and the (meth) acrylic monomer having the glycidyl group is based on the total amount of the monomer mixture (a) having the polymerizable unsaturated double bond. The fiber sizing agent according to claim 1, which is contained in a range of 10% by mass to 70% by mass. The polyoxyalkylene structure is a group consisting of a polyoxyethylene structure, a polyoxyethylene-polyoxypropylene structure, a polyoxyethylene-polyoxybutylene structure, and a structure in which a hydroxyl group at a terminal thereof is sealed with an alkyl group. The fiber sizing agent according to claim 1, which is one or more selected. Carbon fiber or glass fiber bundled by the fiber sizing agent according to any one of claims 1 to 3 . A molded product comprising the carbon fiber or glass fiber according to claim 4 and a matrix resin (C).