JP2023088243A - Composition for bundling fibers, and resin-impregnated fiber, thermoplastic resin composition, and molded article using the same - Google Patents

Abstract

To provide a resin-impregnated fiber which is excellent in a balance between handleability and dispersibility.SOLUTION: A composition for bundling fibers contains a thermoplastic resin emulsion, and has surface tension measured by a ring method at 30°C when solid content concentration is set at 30% of 25-45 mN/m.SELECTED DRAWING: None

Description

The present invention relates to a composition for bundling fibers mainly used in the production of fiber-reinforced thermoplastic resin composites, resin-impregnated fibers bundled with the composition for bundling, and thermoplastic resin compositions and molded articles using the same. It is about.

Fiber materials, typified by carbon fiber, have excellent characteristics such as high strength, high elasticity, and electrical conductivity. It is widely used in various industrial fields such as machinery and sporting goods.

In the production of these fiber-reinforced thermoplastic resin composite materials, the fibers are subjected to a bundling treatment to form a fiber strand, and then (1) a method of making short fibers and melt-kneading with a thermoplastic resin, (2) forming a sheet. It is carried out by laminating it with a thermoplastic resin sheet.

The bundling process integrates several hundred to tens of thousands of independent fibers with a bundling agent to form a strand, and is an essential process for the subsequent step of combining with a thermoplastic resin.

This sizing agent not only imparts abrasion resistance to the fiber strands and affects workability in the composite process, but also wettability and adhesiveness between the essentially incompatible fibers and the thermoplastic resin. etc., and is important because it greatly affects the performance and quality of the final fiber-reinforced thermoplastic resin composite material.

Conventionally, various sizing agents have been studied for the purpose of increasing the affinity between fibers and thermoplastic resins. For example, in Patent Document 1, by bundling fibers with an aqueous emulsion containing a copolymerized nylon resin as a main component, the adhesiveness between the fibers and the thermoplastic resin is improved, and the strength of the fiber-reinforced thermoplastic resin composite material is increased. A method of improvement is disclosed. Alternatively, Patent Literature 2 discloses a method of performing a focusing treatment with a styrene emulsion having a specific carboxyl group content.

Further, in Patent Document 3, a continuous reinforcing fiber sheet made of carbon fiber or the like and a resin sheet made of a thermoplastic resin are alternately laminated, and a heat press treatment (heating and pressurizing treatment) is performed to continuously strengthen the sheet. A fiber-reinforced thermoplastic resin composite material is disclosed in which interstices between fibers are impregnated with a thermoplastic resin.

Furthermore, Patent Document 4 proposes a fiber-reinforced thermoplastic resin composite material formed by laminating sheet-like prepregs impregnated with a thermoplastic resin in the gaps between continuous reinforcing fibers made of carbon fibers or the like. The reinforcing fibers of the pre-preg are pre-cut into a predetermined shape (length) and oriented in a predetermined direction, and then adhered (melt-bonded) by a hot press and laminated to achieve excellent productivity and high performance. It is disclosed that it is possible to obtain a fiber reinforced thermoplastic resin composite material having

JP-A-61-254629 JP 2004-176227 A JP 2013-189634 A International publication WO2016/067711

However, in these methods, although the interfacial adhesive strength between the fiber and the thermoplastic resin is improved, the fiber itself becomes fuzzy due to friction during handling, and the handleability is significantly impaired. On the contrary, problems such as difficulty in uniformly dispersing the fibers in the thermoplastic resin due to excessive fiber bundles occur, and the balance between handling and dispersibility is still satisfactory. The current situation is that it is not.

In view of the above-mentioned circumstances, the present inventors have made intensive studies to solve the problems of the present state of affairs. The inventors have found that resin-impregnated fibers with excellent balance can be obtained, and have completed the present invention.

The present invention consists of the following [1].
[1] A fiber bundling composition containing a thermoplastic resin emulsion and having a solids concentration of 30% and a surface tension of 25 to 45 mN/m as measured by the ring method at 30°C.

The present invention also includes aspects such as the following [2] to [7].
[2] The thermoplastic resin emulsion contains 0.1 to 20% by weight of an ethylenically unsaturated carboxylic acid monomer and 80 to 80% of another monomer copolymerizable with the ethylenically unsaturated carboxylic acid monomer. The composition for fiber bundling according to [1], characterized by containing a copolymer with 99.9% by weight.
[3] The fiber bundling composition according to any one of [1] to [2], which contains at least one of a nonionic surfactant and an anionic surfactant.
[4] Resin-impregnated fibers bundled with the fiber bundling composition according to any one of [1] to [3].
[5] A fiber-reinforced thermoplastic resin composition comprising the resin-impregnated fibers according to [4] and a thermoplastic resin.
[6] A molded article obtained by molding the fiber-reinforced thermoplastic resin composition according to [5].
[7] A molded article obtained by molding a laminate comprising a layer made of the resin-impregnated fiber according to [4] and a thermoplastic resin layer.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a fiber bundling composition excellent in handleability and dispersibility, and a resin-impregnated fiber, a thermoplastic resin composition, and a molded product using the composition.

Hereinafter, the present invention will be described in detail.

The fiber bundling composition of the present invention contains a thermoplastic resin emulsion.

The thermoplastic resin emulsion contained in the fiber bundling composition of the present invention is not particularly limited as long as it is an aqueous dispersion of a thermoplastic resin. Examples include vinylidene resin emulsions, polyamide resin emulsions, aromatic vinyl resin emulsions, acrylic resin emulsions, and olefin resin emulsions.

Among them, the thermoplastic resin emulsion is preferably a copolymer obtained by polymerizing a plurality of monomers containing an ethylenically unsaturated carboxylic acid monomer, from the viewpoint of ease of handling of bundled fibers and performance of the final product. Contains coalescence.

Ethylenically unsaturated carboxylic acid monomers include monocarboxylic acid monomers such as acrylic acid, methacrylic acid and crotonic acid, dicarboxylic acid monomers such as maleic acid, fumaric acid and itaconic acid, and their anhydrides. mentioned. These monomers can be used individually by 1 type or in combination of 2 or more types. The use of acrylic acid, methacrylic acid and itaconic acid is particularly preferred.

Other monomers copolymerizable with ethylenically unsaturated carboxylic acid monomers include aromatic vinyl monomers, vinyl cyanide monomers, alkyl ester monomers, and hydroxyalkyl group-containing monomers. unsaturated monomers, unsaturated carboxylic acid amide-based monomers, vinylpyridine-based monomers, oxazoline-based monomers, and conjugated diene-based monomers. It is possible to use a mixture of more than one species.

Examples of the aromatic vinyl-based monomer include styrene, α-methylstyrene, vinyltoluene, divinylbenzene, and the like, and one or more of these can be used.

Vinyl cyanide monomers include acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, α-ethylacrylonitrile and the like, and one or more of these can be used.

Alkyl ester monomers include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, glycidyl methacrylate, dimethyl fumarate, diethyl fumarate, dimethyl maleate, diethyl malate, dimethyl itaconate, and monomethyl fumarate. , monoethyl fumarate, 2-ethylhexyl acrylate and the like, and one or more of these can be used.

Unsaturated monomers containing hydroxyalkyl groups include β-hydroxyethyl acrylate, β-hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, hydroxybutyl methacrylate, 3-chloro-2-hydroxypropyl methacrylate, di-(ethylene glycol) maleate, di-(ethylene glycol) itaconate, 2-hydroxyethyl maleate, bis(2-hydroxyethyl) maleate, 2-hydroxyethyl methyl fumarate and the like, one of which Or 2 or more types can be used.

Examples of unsaturated carboxylic acid amide-based monomers include acrylamide, methacrylamide, N-methylol acrylamide, N-methylol methacrylamide, N,N-dimethylacrylamide and the like, and one or more of these may be used. can be done.

Vinylpyridine-based monomers include 2-vinylpyridine, 3-vinylpyridine, 4-vinylpyridine, 2-methyl-5-vinylpyridine and the like, and one or more of these may be used. .

Examples of oxazoline-based monomers include 2-vinyl-2-oxazoline and 4,4-dimethyl-2-vinyl-2-oxazoline-5-one, and one or more of these may be used. can be done.

Conjugated diene monomers include 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2-chloro-1,3-butadiene and the like. , these can be used alone or in combination of two or more.

Among others, other monomers copolymerizable with ethylenically unsaturated carboxylic acid monomers include styrene, α-methylstyrene, acrylonitrile, methyl methacrylate, butyl acrylate, β-hydroxyethyl acrylate, acrylamide or methacrylamide, 2 -Vinylpyridine, 1,3-butadiene is preferred.

The content of the ethylenically unsaturated carboxylic acid monomer in all monomers is preferably 0.1 to 20% by weight, more preferably 0.5 to 18% by weight, and 1 to 16% by weight. More preferred. Adjustment within this range tends to provide an excellent balance between bundling properties and fiber dispersibility in the final product.

The preferable composition ratio of each monomer in the thermoplastic resin emulsion is 60 to 95% by weight of aromatic vinyl monomer, 4 to 39% by weight of vinyl cyanide monomer, and ethylenically unsaturated carboxylic acid monomer. 1 to 15% by weight of aromatic vinyl monomers, 5 to 15% by weight of vinyl cyanide monomers, and ethylenically unsaturated carboxylic acid monomers. from 1 to 5% by weight.

When the thermoplastic resin emulsion contained in the composition for fiber bundling of the present invention is obtained by emulsion polymerization, known emulsion polymerization methods such as batch addition method, divided addition method, continuous addition method, multistage polymerization method, seed Any of a polymerization method, a power feed polymerization method, and the like may be employed. Among them, the continuous addition method is preferable because of the stability during polymerization and the ease of adjusting the molecular weight.

Examples of emulsifiers used in emulsion polymerization of the thermoplastic resin emulsion contained in the fiber bundling composition of the present invention include higher alcohol sulfate salts, alkylbenzenesulfonates, alkyldiphenylether disulfonates, and aliphatic sulfones. acid salts, aliphatic carboxylates, dehydroabietic acid salts, formalin condensates of naphthalenesulfonic acid, anionic surfactants such as sulfate ester salts of nonionic surfactants, polyethylene glycol alkyl ester types, alkylphenyl ethers and alkyl ether type nonionic surfactants. These can be used individually by 1 type or in combination of 2 or more types. The amount of the emulsifier to be blended can be appropriately adjusted in consideration of the combination with other additives. Among them, alkylbenzenesulfonates, alkyldiphenylether disulfonates, aliphatic sulfonates, and nonionic surfactants are preferred from the viewpoint of emulsion stability.

The emulsifier used in the emulsion polymerization is preferably used in an amount of 0.05 to 10 parts by weight per 100 parts by weight of all the monomers. If it is less than 0.05 part by weight, the stability of the emulsion is poor and the yield at the time of impregnation treatment is lowered. Product strength tends to decrease. The range is preferably 0.06 to 8 parts by weight, more preferably 0.08 to 5 parts by weight.

Examples of polymerization initiators used in emulsion polymerization of the thermoplastic resin emulsion contained in the fiber bundling composition of the present invention include water-soluble polymerization initiators such as lithium persulfate, potassium persulfate, sodium persulfate and ammonium persulfate. Oil-soluble polymerization initiation initiators such as cumene hydroperoxide, benzoyl peroxide, t-butyl hydroperoxide, acetyl peroxide, diisopropylbenzene hydroperoxide, and 1,1,3,3-tetramethylbutyl hydroperoxide agents. These can be used individually by 1 type or in combination of 2 or more types. Among these, it is preferable to use potassium persulfate, sodium persulfate, cumene hydroperoxide, or t-butyl hydroperoxide. The amount of the polymerization initiator to be blended is appropriately adjusted in consideration of the monomer composition, the pH of the polymerization reaction system, the combination of other additives, and the like.

Examples of chain transfer agents used in emulsion polymerization of the thermoplastic resin emulsion contained in the fiber bundling composition of the present invention include n-hexylmercaptan, n-octylmercaptan, t-octylmercaptan, and n-dodecylmercaptan. , t-dodecyl mercaptan, n-stearyl mercaptan and other alkyl mercaptans; dimethyl xanthogen disulfide, diisopropyl xanthogen disulfide and other xanthogen compounds; tetramethyl thiuram disulfide, tetraethyl thiuram disulfide, tetramethyl thiuram monosulfide and other thiuram compounds; ,6-di-t-butyl-4-methylphenol, phenolic compounds such as styrenated phenol; allyl compounds such as allyl alcohol; halogenated hydrocarbon compounds such as dichloromethane, dibromomethane, carbon tetrabromide; α-benzyl Vinyl ethers such as oxystyrene, α-benzyloxyacrylonitrile, α-benzyloxyacrylamide; triphenylethane, pentaphenylethane, acrolein, methacrolein, thioglycolic acid, thiomalic acid, 2-ethylhexylthioglycolate, terpinolene, α-methyl Chain transfer agents such as styrene dimer are included. These can be used individually by 1 type or in combination of 2 or more types. The blending amount of the chain transfer agent can be appropriately adjusted in consideration of the combination with other additives.

Examples of the reducing agent used in emulsion polymerization of the thermoplastic resin emulsion contained in the fiber bundling composition of the present invention include sulfite, hydrogen sulfite, pyrosulfite, nitionite, nitionate, thiosulfate, formaldehyde sulfonate, benzaldehyde sulfonate; carboxylic acids such as L-ascorbic acid, erythorbic acid, tartaric acid and citric acid and salts thereof; reducing sugars such as dextrose and saccharose; Amines are mentioned. These can be used individually by 1 type or in combination of 2 or more types. Among these, L-ascorbic acid and erythorbic acid are preferred. The blending amount of the reducing agent can be appropriately adjusted in consideration of the combination with other additives.

For the purpose of controlling the molecular weight and crosslinked structure of the copolymer, the reaction system according to the present embodiment contains saturated hydrocarbons such as pentane, hexane, heptane, octane, cyclohexane, and cycloheptane; pentene, hexene, heptene, Hydrocarbon compounds such as unsaturated hydrocarbons such as cyclopentene, cyclohexene, cycloheptene, 4-methylcyclohexene and 1-methylcyclohexene; aromatic hydrocarbons such as benzene, toluene and xylene can be blended. These can be used individually by 1 type or in combination of 2 or more types. Among these, it is preferable to use cyclohexene and toluene.

The polymerization temperature during emulsion polymerization is preferably in the range of 30 to 85° C., and the polymerization time is preferably in the range of 3 to 20 hours.

In addition to the thermoplastic resin emulsion, the fiber bundling composition of the present invention also contains emulsifiers, dispersants, lubricants, antifoaming agents, preservatives, antioxidants, ultraviolet absorbers, light stabilizers, colorants, Antistatic agents, plasticizers, and the like can be blended and used within a range that does not impair the effects of the present invention.

The content of the thermoplastic resin emulsion (in terms of solid content) in the fiber bundling composition of the present invention is preferably 80% by weight or more, more preferably 90% by weight or more.

The weight-average molecular weight of the thermoplastic resin emulsion in the fiber bundling composition of the present invention is preferably in the range of 1.0×10 ⁴ to 8×10 ⁴ . If the weight-average molecular weight is lower than 1.0×10 ⁴ , the strength of the final product, which is the object of the present invention, will be poor, and if it exceeds 8×10 ⁴ , the impregnation between fibers, which is the feature of the present invention, will be reduced. . More preferably 2×10 ⁴ to 7.5×10 ⁴ , still more preferably 2.5×10 ⁴ to 7×10 ⁴ , particularly preferably 3.5×10 ⁴ to 6.8×10 ⁴ , most preferably It is in the range of 4×10 ⁴ to 6.5×10 ⁴ .

The weight-average molecular weight of the thermoplastic resin emulsion was measured using a commercially available gel permeation chromatogram (GPC) measuring device equipped with a UV detector and a column (MIXD-B manufactured by Agilent) at a column temperature of 50°C and a solvent It is a polystyrene-equivalent molecular weight measured under the conditions of tetrahydrofuran (THF), a flow rate of 1 ml/min, and a detection wavelength of 254 nm.

Although the glass transition temperature of the solid content of the thermoplastic resin emulsion in the fiber bundling composition of the present invention is not particularly limited, it is preferably in the range of 30 to 200° C. from the standpoint of the strength of the final product. The range is more preferably 35 to 190°C, still more preferably 60 to 140°C, and particularly preferably 80 to 120°C. This glass transition temperature can be measured according to JIS K7121-2012. The method for extracting the solid content in the thermoplastic resin emulsion is not particularly limited, but it can be obtained, for example, by drying the thermoplastic resin emulsion in a dryer adjusted to 90° C. for 10 hours.

The surface tension of the fiber bundling composition of the present invention is required to be 25 to 45 mN/m, particularly preferably 26 to 42 mN/m, particularly preferably 27 to 40 mN/m. If the surface tension exceeds 45 mN/m, the uniform adhesion of the thermoplastic resin emulsion to the reinforcing fibers is lowered, and the adhesiveness between the thermoplastic matrix resin and the reinforcing fibers is deteriorated. On the other hand, when the surface tension is less than 25 mN/m, it becomes difficult to control the amount of the sizing agent attached to the reinforcing fibers.

Surface tension can be measured, for example, by the method described in Examples.

This surface tension can be adjusted by the content of the ethylenically unsaturated carboxylic acid monomer and the type and amount of the emulsifier added to the thermoplastic resin emulsion. The type of emulsifier added to the thermoplastic resin emulsion is preferably at least one of nonionic surfactants and anionic surfactants, such as acetylene glycol type nonionic surfactants, dodecylbenzene sulfone At least one of sodium sulfate and dialkylsulfosuccinate-based anionic surfactants is more preferred. The amount of emulsifier to be added is preferably 0.5 to 2.5 parts by weight with respect to 100 parts by weight (solid content) of the thermoplastic resin emulsion.

The method for bundling fibers with the composition for fiber bundling of the present invention is not particularly limited, and it is possible to select one or a combination of two or more of known methods such as a spray method, a coating method, and an impregnation method. .

Fibers to be bundled by the fiber bundling composition of the present invention include carbon fibers, glass fibers, boron fibers, silicon carbide fibers, metal fibers such as aluminum fibers, stainless steel fibers, copper fibers, nickel fibers, polyamide fibers, and polyester fibers. , polyarylate fibers, polyimide fibers, and (nano)cellulose fibers. Furthermore, these fibers can be used singly or in combination of two or more. Among them, carbon fiber and glass fiber are preferred. In addition to ordinary carbon fibers, carbon fibers include carbon fibers coated with metal such as nickel, and there are no particular restrictions on the form thereof, and may be continuous fibers, chopped fibers, milled shapes, non-woven fabrics, etc. Any form can be selected according to the requirements.

Although there is no particular restriction on the impregnation ratio of the fiber bundling composition and the fibers in the present invention, from the standpoint of the strength of the final product, 1 to 20 parts by weight of the fiber bundling composition and 99 to 80 parts by weight of the fiber are used in terms of solid content. Impregnation in the range is preferred.

In the resin-impregnated fiber of the present invention, the method for evaporating the moisture in the fiber bundled with the fiber bundling composition is not particularly limited, and the method is a method using a dryer, a method of irradiating infrared rays, and a method of continuously passing through a dryer. It is possible to adopt according to the purpose, such as a method of The drying temperature is preferably adjusted to the glass transition temperature of the thermoplastic resin emulsion plus 60 to 80° C. for handling the fibers after the bundling treatment.

The resin-impregnated fiber of the present invention can be melt-kneaded with a thermoplastic resin and used as a fiber-reinforced thermoplastic resin composition. Furthermore, it can also be used as a laminate laminated with a thermoplastic resin sheet or film.

Thermoplastic resins to be combined with the resin-impregnated fiber of the present invention include, for example, polystyrene (PS), high-impact polystyrene (HIPS), acrylonitrile-butadiene rubber-styrene copolymer (ABS), acrylonitrile-acrylic rubber-styrene copolymer. Styrene resins such as coalescence (ASA), acrylonitrile-ethylene propylene rubber-styrene copolymer (AES), acrylonitrile-styrene copolymer (AS), polyolefin resins such as polyethylene (PE) and polypropylene (PP), polycarbonate ( PC), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyester resins such as polylactic acid resin (PLA), polymethyl methacrylate resin (PMMA), polyamide resin (PA), thermoplastic polyurethane resin (TPU), poly Examples include alloys of ether sulfone (PES), polyphenylene sulfide (PPS) or styrene resins and one or more resins selected from polyester resins and polyamide resins. It is possible to use more than one species in combination. Among them, styrene resins, polyester resins, polyamide resins, and alloys of styrene resins and polyester resins or polyamides are preferred from the viewpoint of the balance between moldability and strength of the final product.

The thermoplastic resin to be combined with the resin-impregnated fiber of the present invention includes, for example, light stabilizers, antioxidants, heat stabilizers, ultraviolet absorbers, lubricants, flame retardants, flame retardant aids, plasticizers, pigments, dyes, and the like. can also contain various additives.

The fiber-reinforced thermoplastic resin composition obtained by melt-kneading the resin-impregnated fiber and thermoplastic resin of the present invention can be, for example, injection molding, multilayer extrusion molding, film molding, sheet molding, inflation molding, press molding, SMC. A molded product can be obtained by adopting a processing method according to the purpose, such as a molding method or an LFT-D method. In some cases, it is also possible to interpose a step of pre-shaping.

In addition to the above processing methods, it is possible to obtain a molded product by press molding, SMC molding, etc., using a laminate obtained by laminating a layer made of the resin-impregnated fiber of the present invention with a thermoplastic resin sheet or film. is. In some cases, it is also possible to interpose a step of pre-shaping.

There is no particular limitation on the processing temperature of the molded product, and it is possible to select any temperature according to the properties of the thermoplastic resin used, but it is preferable to mold in the range of 180 to 300 ° C. from the viewpoint of the molding cycle. , and more preferably in the range of 200 to 280°C.

EXAMPLES Hereinafter, the present embodiment will be described in more detail using Examples and Comparative Examples, but the present embodiment is not limited by the following Examples. Various physical properties in each example and comparative example are measured by the following methods.

The obtained thermoplastic resin emulsion was dried at room temperature for a whole day and night, and then dried in an oven at 70° C. for 1 hour to obtain a measurement sample. After that, a solution prepared by dissolving 0.02 g of the measurement sample in 10 ml of tetrahydrofuran (THF) was measured using a gel permeation chromatogram (GPC) measurement device under the following conditions.
Detector: UV
Column: MIXD-B manufactured by Agilent
Column temperature: 50°C
Solvent: Tetrahydrofuran (THF)
Flow rate: 1 ml/min,
Detection wavelength: 254 nm
Standard sample: Polystyrene
Glass-transition temperature
The resulting thermoplastic resin emulsion was dried in an oven at 90° C. for 10 hours to prepare a measurement sample. After that, it was measured according to JIS K7121-2012 using a differential scanning calorimeter.

Pure water was added to the surface tension fiber bundling composition to adjust the solid content to 30%, and then the surface tension was measured at 30°C using an automatic surface tension meter K11 (manufactured by KRUSS).

Evaluation of bundling property During the production of the fiber-reinforced thermoplastic resin compositions obtained in each example and comparative example, the state of the chopped strands inside the shooter installed in F2 for charging the chopped strands was visually observed, and the following was performed. evaluated to
×: Significant fluffing △: Partial fluffing 〇: No fluffing confirmed In addition, the continuous resin-impregnated fibers obtained in each example and comparative example were cut into a length of 20 cm and cut into a pipe with a diameter of 30 mm. The state of the fiber when it was bent in the form of being attached was visually observed and evaluated as follows.
×: Significant fraying of fibers occurred △: Partial fraying of fibers occurred ○: Abnormality was not confirmed The better the evaluation of bundling property, the better the handleability.

Evaluation of Openability The test pieces used for evaluation of openability obtained in each of the Examples and Comparative Examples were observed for the dispersion state of the carbon fibers inside using an X-ray CT apparatus (SkyScan 1272 manufactured by Bruker).
In addition, the better the evaluation of the openability, the better the dispersibility.
×: Carbon fibers are remarkably unevenly distributed △: Some carbon fibers are not dispersed ○: Carbon fibers are uniformly dispersed <Method for producing thermoplastic resin emulsion (1)>
After adding 45 parts by weight of pure water to the polymerization reactor, the reactor was purged with nitrogen. Thereafter, the temperature was started to rise, and when the temperature reached 75°C, 0.2 parts by weight of potassium persulfate was added. Furthermore, when the reactor reached 80° C., a solution of 2.1 parts by weight of sodium dodecylbenzenesulfonate (in terms of solid content) dissolved in 30 parts by weight of pure water, 88 parts by weight of styrene, 10 parts by weight of acrylonitrile, and acrylic acid were added. A continuous addition of a monomer mixture consisting of 2 parts by weight and 0.8 parts by weight of t-dodecyl mercaptan was initiated over a period of 7.5 hours. The temperature of the reactor was maintained at 80° C. during that time, and after the continuous addition was completed, the temperature was maintained at 80° C. for 5 hours in order to complete the polymerization. After that, pure water was used to adjust the solid content to 45% to obtain a thermoplastic resin emulsion (1).

The solid content in the thermoplastic resin emulsion (1) had a weight average molecular weight of 5.4×10 ⁴ and a glass transition temperature of 102°C.

<Method for producing thermoplastic resin emulsion (2)>
Heating was carried out in the same manner as the thermoplastic resin emulsion (1), except that the monomer mixture was changed to 86 parts by weight of styrene, 9 parts by weight of acrylonitrile, 0.8 parts by weight of t-dodecylmercaptan, and 5 parts by weight of methacrylic acid. A plastic resin emulsion (2) was obtained.

The solid content in the thermoplastic resin emulsion (2) had a weight average molecular weight of 5.2×10 ⁴ and a glass transition temperature of 103°C.

<Method for producing thermoplastic resin emulsion (3)>
Thermoplastic resin emulsion (3) was prepared in the same manner as thermoplastic resin emulsion (1) except that the monomer mixture was changed to 90 parts by weight of styrene, 10 parts by weight of acrylonitrile, and 0.8 parts by weight of t-dodecylmercaptan. Obtained.

The solid content in the thermoplastic resin emulsion (3) had a weight average molecular weight of 5.0×10 ⁴ and a glass transition temperature of 100°C.

<Method for producing fiber bundling composition (1)>
The thermoplastic resin emulsion (1) was used as the fiber bundling composition (1). The surface tension measured by the method described above was 40 mN/m.

<Method for producing fiber bundling composition (2)>
After adding 1 part by weight of acetylene glycol-type nonionic surfactant (Surfinol (registered trademark) 104E manufactured by Nissin Chemical Industry Co., Ltd.) to 100 parts by weight (solid content) of thermoplastic resin emulsion (1) The mixture was sufficiently stirred to obtain a fiber bundling composition (2). The surface tension measured by the method described above was 27 mN/m.

<Method for producing fiber bundling composition (3)>
After adding 2 parts by weight of sodium dodecylbenzenesulfonate to 100 parts by weight (solid content) of thermoplastic resin emulsion (1), the mixture was sufficiently stirred to obtain a fiber bundling composition (3). The surface tension measured by the method described above was 29 mN/m.

<Method for producing fiber bundling composition (4)>
To 100 parts by weight (solid content) of thermoplastic resin emulsion (1), 1 part by weight of a dialkylsulfosuccinate-based anionic surfactant (Sanmorin (registered trademark) OT-70 manufactured by Sanyo Chemical Industries, Ltd.) was added. After that, the mixture was sufficiently stirred to obtain a fiber bundling composition (4). The surface tension measured by the method described above was 27 mN/m.

<Method for producing fiber bundling composition (5)>
The thermoplastic resin emulsion (2) was used as a fiber bundling composition (5). The surface tension measured by the method described above was 36 mN/m.

<Method for producing fiber bundling composition (6)>
The thermoplastic resin emulsion (3) was used as a fiber bundling composition (6). The surface tension measured by the method described above was 55 mN/m.

<Method for producing fiber bundling composition (7)>
To 100 parts by weight of the thermoplastic resin emulsion (1), 4 parts by weight of a dialkylsulfosuccinate-based anionic surfactant (Sanmorin (registered trademark) OT-70 manufactured by Sanyo Chemical Industries, Ltd.) was added and thoroughly stirred. A fiber bundling composition (7) was obtained. The surface tension measured by the method described above was 24 mN/m.

<Method for producing chopped strand (1)>
After bundling the fiber bundling composition (1) (in terms of solid content) so that the adhesion amount is 3 parts by weight with respect to 100 parts by weight of continuous carbon fibers, cutting is performed using a pelletizer, and the temperature is adjusted to 100 ° C. Drying was carried out using a rack type dryer until the moisture content became 0.1% or less to obtain Chopped Strand (1).

<Method for producing chopped strands (2) to (7)>
Chopped strands (2) to (7) were obtained in the same manner as the chopped strand (1) except that the fiber bundling composition (1) was changed to the fiber bundling composition (2) to (7).

<Method for producing continuous resin-impregnated fiber (1)>
Using a cloth binding device, the fiber bundling composition (1) (converted to solid content) was bundled so that the adhesion amount was 10 parts by weight (converted to solid content) with respect to 100 parts by weight of carbon fiber, and then obtained The continuous resin-impregnated fiber was moved in a drying oven adjusted to 180° C. at a speed of 1 m/min for 3 minutes to completely remove moisture, thereby obtaining the final continuous resin-impregnated fiber (1).

<Method for producing continuous resin-impregnated fibers (2) to (7)>
Continuous resin-impregnated fibers (2) to (7) are produced in the same manner as the continuous resin-impregnated fiber (1) except that the fiber bundling composition (1) is changed to the fiber bundling composition (2) to (7). got

Carbon fibers used for the chopped strands and continuous resin-impregnated fibers described above are Tenax (registered trademark)-J STS40 F13 24K 1600tex manufactured by Teijin Limited.

Thermoplastic resin (1)
Nippon A&L Co., Ltd. Clarastick (registered trademark) GA-501
(ABS resin)
Thermoplastic resin (2)
Techniace (registered trademark) TA-1500 manufactured by Nippon A&L Co., Ltd.
(Alloy of polyamide resin and ABS resin)
Thermoplastic resin (3)
Techniace (registered trademark) PAX-1439 manufactured by Nippon A&L Co., Ltd.
(alloy of polycarbonate resin and ABS resin)
<Method for producing fiber-reinforced thermoplastic resin composition>
After mixing the thermoplastic resin and chopped strands at the blending ratio shown in Table 1, the thermoplastic resin was chopped from F1 and the chopped strands from F2 using OMega30H manufactured by STEER, which has two feeders set at 260 ° C. A strand was added and melt-kneaded to obtain pellets of a fiber-reinforced thermoplastic resin composition. Using the pellets, a test piece for Charpy impact strength was molded with an injection molding machine, and a 5 mm × 5 mm × 4 mm test piece was cut from the center of the obtained molded product and used for evaluation of openability.

<Method for producing a laminated product composed of continuous resin-impregnated fibers and thermoplastic resin>
After arranging a plurality of continuous resin-impregnated fibers in parallel to form a 20 cm square sheet, a polyamide resin film (Rayfan (registered trademark) NO 1401, thickness 40 μm, manufactured by Toray Advanced Film Co., Ltd.) and a carbon fiber content of 30% by weight. After preheating for 5 minutes with a pressure of 5 MPa using a compression molding machine NF37 with a set temperature of 250 ° C., hot press treatment is performed for 5 minutes with a pressure of 15 MPa. to produce a laminate having a thickness of 2 mm. A test piece having a width of 5 mm and a length of 5 mm was cut out from the obtained laminated product and used for the evaluation of openability.

Since Examples 1 to 15 are fiber bundling compositions that satisfy the surface tension specified in the present invention, they were excellent in the balance between the bundling property and the fiber opening property.

Comparative Examples 1 to 4 were fiber bundling compositions that did not satisfy the surface tension specified in the present invention, and were inferior in bundling and opening properties.

As described above, the product of the present invention can produce resin-impregnated fibers that are superior in balance between handling and dispersibility compared to impregnated fibers using conventional sizing agents. Suitable for parts and electrical appliances.

Claims (7)

A fiber bundling composition containing a thermoplastic resin emulsion and having a surface tension of 25 to 45 mN/m as measured by the ring method at 30° C. when the solid content concentration is 30%. The thermoplastic resin emulsion contains 0.1 to 20% by weight of an ethylenically unsaturated carboxylic acid monomer and 80 to 99.9% of another monomer copolymerizable with the ethylenically unsaturated carboxylic acid monomer. A composition for fiber bundling according to claim 1, characterized in that it contains a copolymer of . 2. The fiber bundling composition according to claim 1, comprising at least one of a nonionic surfactant and an anionic surfactant. A resin-impregnated fiber bundled with the fiber bundling composition according to any one of claims 1 to 3. A fiber-reinforced thermoplastic resin composition comprising the resin-impregnated fiber according to claim 4 and a thermoplastic resin. A molded article obtained by molding the fiber-reinforced thermoplastic resin composition according to claim 5 . A molded article obtained by molding a laminate comprising a layer comprising the resin-impregnated fiber according to claim 4 and a thermoplastic resin layer.