JP2926227B1 - Sizing agent for glass fiber - Google Patents

Abstract

Abstract: PROBLEM TO BE SOLVED: To provide a glass fiber sizing agent which is more excellent in fuzz suppression property than conventional ones. SOLUTION: An isocyanate group-terminated urethane prepolymer (A) derived from a polyester polyol having a number average molecular weight of 500 to 4000 and an excess of an aliphatic polyisocyanate is converted into a polyoxyalkylene ether (B1) of a polycyclic phenol. Or (B1) and a polyoxyethylene ether of polypropylene glycol (B
Dispersed in water in the presence of an emulsifier (B) consisting of 2),
It comprises an aqueous dispersion of a polyurethane polyurea resin obtained by chain extension with water or a polyamine.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a sizing agent for glass fibers. More specifically, the present invention relates to a sizing agent for glass fibers which is excellent in suppressing fluffing.

[0002]

2. Description of the Related Art Glass fibers are inherently brittle, and easily break when damaged by impact such as friction. For this reason, various types of glass fiber sizing agents have been used in the past to protect glass fibers from friction during winding, twisting, tube winding, and weaving in the glass fiber manufacturing process and to prevent fluffing and yarn breakage. Have been. Conventionally, as a sizing agent for glass fiber, starch, processed starch, dextrin, starch such as amylose, carboxymethyl cellulose, polyvinyl alcohol, acrylamide-vinyl acetate copolymer, and aqueous polyurethane resin (for example, Japanese Patent Publication No. Sho 52-6393) Although synthetic polymer compounds such as these have been used, it cannot be said that the generation of fluff of glass fibers is sufficiently suppressed because the formed dry film is hard and brittle.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a sizing agent for glass fibers which improves the above-mentioned drawbacks found in the conventional sizing agent for glass fibers and has an excellent property of suppressing fuzzing.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above problems, and as a result, by using a specific aqueous polyurethane polyurea resin as a sizing agent for glass fibers, the present invention has excellent fuzz suppression. The present inventors have found that a sizing agent for glass fibers can be obtained, and have reached the present invention. That is, the present invention provides an isocyanate group-terminated urethane derived from a polyester polyol (A1) having a number average molecular weight of 500 to 4,000 and, if necessary, a low molecular polyol (A2) and an excess of an aliphatic polyisocyanate (A3). Dispersing the prepolymer (A) in water in the presence of a polyoxyalkylene ether (B1) of a polycyclic phenol or an emulsifier (B) comprising the (B1) and a polyoxyethylene ether (B2) of polypropylene glycol; A sizing agent for glass fiber, comprising an aqueous dispersion of a polyurethane polyurea resin obtained by chain extension with water or a polyamine.

The polyester polyol (A1) constituting the isocyanate group-terminated urethane prepolymer (A) in the present invention includes, for example, a polycarboxylic acid or an ester-forming derivative thereof [eg, an aliphatic polycarboxylic acid (maleic acid, fumaric acid) , Succinic acid, adipic acid, azelaic acid, etc.), aromatic polycarboxylic acids (terephthalic acid, isophthalic acid, trimellitic acid, pyromellitic acid, etc.), anhydrides thereof, lower alkyl (1-4 carbon atoms) esters Etc.] and a low molecular polyol [alkylene glycol having usually 2 to 10, preferably 2 to 6 carbon atoms (eg, ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, 3-methyl- 1,5-pentanediol, neopentyl glycol Etc.), alicyclic diols (e.g. 1,4-dihydroxy cyclohexane, etc.); 3
Alcohols (e.g., glycerin, trimethylolpropane, etc.); alkylene oxides (e.g., ethylene oxide, propylene oxide, etc.) of low molar adducts (molecular weight less than 500); polyhydric phenols (bisphenols, such as bisphenol A, bisphenol F) Condensed polyester polyol (eg, polyethylene adipate diol, polybutylene adipate diol, polyhexamethylene adipate diol, polyneopentyl adipate diol, polyethylene) / Butylene adipate diol, polyneopentyl / hexyl adipate diol, poly-3-methylpentane adipate diol, polybutylene isophate Rate diol, etc.); one or more lactone monomers of the low molecular polyol (gamma
Valerolactone, 3-methyl-γ-valerolactone,
polylactone polyols obtained by ring-opening polyaddition of ε-caprolactone (eg, polycaprolactone diol or triol, poly-3-methylvalerolactone diol); one or more of the above low-molecular polyols and a carbonate (dimethyl carbonate) , Ethylene carbonate, etc.) and polycarbonate polyols (for example, polyhexamethylene carbonate diol, etc.); and mixtures of two or more thereof.
Among these, preferred are the condensed polyester polyols, more preferred are the polyester polyols derived from aliphatic dicarboxylic acids and low molecular weight glycols, and particularly preferred are adipic acid and alkylene glycols having 2 to 6 carbon atoms. And polyalkylene adipate diols derived from at least one of the following.

The number average molecular weight of the (A1) is usually 500
４4000, preferably 800-3000. When the number average molecular weight is less than 500, the resulting dried film of the aqueous polyurethane polyurea resin becomes hard,
If it exceeds 0, the adhesiveness to the glass fiber is reduced, and in any case, the fuzz suppression of the glass fiber tends to be poor.

The melting point of (A1) is 40 ° C. or less, especially 20 ° C.
C. or lower is preferred. When the melting point exceeds 40 ° C., the obtained dried film of the polyurethane polyurea resin becomes hard, and the fuzz suppression of the glass fiber may be insufficient.

The low molecular polyol (A2) optionally used together with the above (A1) includes, for example, the low molecular glycol exemplified as the raw material of the above (A1) or a low molar addition of an alkylene oxide thereof (such as ethylene oxide or propylene oxide). (Number average molecular weight less than 500); bisphenols (bisphenol A,
Low-molar alkylene oxide adducts of bisphenol F, bisphenol S, etc.) (number average molecular weight less than 500); trihydric or higher alcohols [eg glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, low-molar alkylene oxide adducts thereof (Number average molecular weight less than 500)];
Mixtures of more than one species. Preferred among these are low molecular glycols and low molar adducts of alkylene oxides. When (A1) and (A2) are used in combination, the amount of (A2) is usually at most 30% by weight, preferably at most 20% by weight, based on the total amount of (A1) and (A2).

Examples of the aliphatic polyisocyanate (A3) include, for example, carbon number (excluding carbon in NCO group) of 4
To 15 alicyclic diisocyanates [e.g., isophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate (hydrogenated MDI), 1,4-
Cyclohexylene diisocyanate, 2,4- or 2,6-methylcyclohexylene diisocyanate (hydrogenated TDI), bis (2-isocyanatoethyl) -4-cyclohexene-1,2-dicarboxylate, 2,5-
Or 2,6-norbornane diisocyanate]; an aliphatic diisocyanate having 2 to 18 carbon atoms (excluding carbon in the NCO group) [for example, ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), dodecamethylene diisocyanate, 6,11-undecane triisocyanate, 2,2,4- or 2,4,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, 2,6-diisocyanatomethyl caproate, bis (2-isocyanatoethyl) fumarate, Bis (2-isocyanatoethyl) carbonate, 2-isocyanatoethyl-2,6-diisocyanatohexanoate and the like];
Aromatic aliphatic polyisocyanate having 8 to 15 carbon atoms (excluding carbon in NCO group) (for example, xylylene diisocyanate, α, α, α ′, α′-tetramethylxylylene diisocyanate); modified products of these diisocyanates (Isocyanurate, buret, uretdione, trimethylolpropane adduct, etc.); and mixtures of two or more of these. Of these, preferred are isophorone diisocyanate, 4,4 ′
-Dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate and 2,2,4- or 2,4,4-trimethylhexamethylene diisocyanate, particularly preferred are isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate and Methylene diisocyanate.

The method for producing the isocyanate group-terminated urethane prepolymer (A) in the present invention is not particularly limited, and (A1) and, if necessary, (A1) can be obtained by a usual method for producing a polyurethane resin (one-shot method or multi-step method). It is obtained by subjecting A2) and an excess of (A3) to a urethanization reaction. The reaction temperature for urethanization is usually 30 to 200 ° C, preferably 50 to 180 ° C. The reaction time is generally 0.1 to 30 hours, preferably 0.1 to 8 hours.
Time. The urethanization reaction is usually performed in a solventless system, but may be performed in an organic solvent inert to isocyanate, if necessary. Examples of the organic solvent include acetone, tetrahydrofuran, dimethylformamide, dimethylsulfoxide, toluene, dioxane, ethyl acetate and the like.

In the urethanization reaction, the equivalent ratio (NCO / OH) of the isocyanate group in (A3) to the total hydroxyl group in (A1) and (A2) is usually 1.1 to 3, preferably 1.2. To 2, particularly preferably 1.2 to 1.6. The isocyanate group-terminated urethane prepolymer (A) generally has an isocyanate group content of 0.5 to 0.5%.
It is 10% by weight, preferably 0.7-5% by weight.

In the present invention, the emulsifier (B) used for dispersing and chain-extending the isocyanate group-terminated urethane prepolymer (A) in water includes a polyoxyalkylene ether (B1) of a polycyclic phenol or A mixture of (B1) and polyoxyethylene ether (B2) of polypropylene glycol is used.

The polyoxyalkylene ethers (B1) of polycyclic phenols generally have 2 to 20 aromatic rings.
Preferred are compounds obtained by adding alkylene oxide to 2 to 12 polycyclic phenols. Examples of the polycyclic phenols include bicyclic phenols such as phenylphenol, cumylphenol, α- or β-naphthol; and those bicyclic phenols and monocyclic phenols [monohydric phenols such as phenol Phenols having 1 to 15 carbon atoms in the alkyl group (cresol, butylphenol, octylphenol, nonylphenol, dodecylphenol, etc.); dihydric phenols such as catechol, etc., and styrenes ( Styrene, α-methylstyrene, vinyltoluene, etc.) in an amount not exceeding 19 mol, preferably 1 to 10 mol.
Compounds added by mole are exemplified. Styrenes can be added to phenols by, for example, a known method known as the Friedel-Crafts reaction. For example, in the presence of an acidic catalyst such as anhydrous aluminum chloride, boron trifluoride, sulfuric acid, phosphoric acid, antimony pentachloride, activated clay, etc.
The reaction is carried out at a temperature of 〜140 ° C. Although the structure of the compound obtained by reacting the phenols with a large number of styrenes is not sufficiently clear, styrenes are first polymerized to form styrene oligomers other than those obtained by adding styrenes to the benzene nucleus of the phenols. Forming
It is conceivable that the oligomer is added to the benzene nucleus of phenols, or that the styrenes are sequentially added to the benzene nucleus of styrenes added to the phenol. These compounds can be used as an intermediate of (B1) as a mixture without particular isolation. Preferred as the polycyclic phenols are styrene (2 to 10 mol) phenol, styrene (2 to 10 mol) cumylphenol and α-methylstyrene (2 to 10 mol).
Phenol.

The alkylene oxide forming (B1) includes ethylene oxide (hereinafter abbreviated as EO), propylene oxide (hereinafter abbreviated as PO),
1,2-, 1,3- or 2,3-butylene oxide, tetrahydrofuran, α-olefin (having 4 to 4 carbon atoms)
30) Oxides, styrene oxides and the like alone and mixtures of two or more thereof. Of these, EO alone and a combination of EO and PO are preferred. In the case of combined use, the mode of bonding of the alkylene oxide may be either block or random. The addition mole number of the alkylene oxide is usually 3 to 100 mol, preferably 5 to 50 mol.

The polyoxyethylene ether (B2) of polypropylene glycol has a number average molecular weight of 50.
5 EO to 0-3,000 polypropylene glycol
What added 300 mol is mentioned. (B2)
Are preferably number average molecular weights of 1,000 to 2.5.
No. 00 polypropylene glycol with 7 to 200 moles of EO added.

As the emulsifier (B) used for dispersing and elongating the isocyanate group-terminated urethane prepolymer (A) in water, a combination of (B1) and (B2) is preferable.
The ratio is not particularly limited, but is usually 100: 0 to 2:
98, preferably 2:98 to 98: 2, particularly preferably 10:90 to 90:10.

In the present invention, when the isocyanate group-terminated urethane prepolymer (A) is dispersed and chain-extended in water, (B1) or (B1) is used as an emulsifier (B).
The mixture of (B1) and (B2) is essentially used,
Alternatively, if necessary, another emulsifier (B3) may be used together with (B1) and (B2). As (B3), a nonionic surfactant [for example, having 10 to 20 carbon atoms]
Ethylene oxide adducts of higher alcohols (lauryl alcohol, sarylyl alcohol, etc.), ethylene oxide adducts of alkyl phenols having 8 to 14 carbon atoms (nonylphenol, dodecylphenol, etc.), higher fatty acids (lauric acid, oleic acid) , Stearic acid, etc.), ethylene oxide adducts of fatty acid esters of polyhydric alcohols (such as sorbitan), ethylene oxide adducts of alkylamines having 8 to 20 carbon atoms (laurylamine, oleylamine, etc.), higher fatty acids Ethylene oxide adducts of amides (such as lauric amide), ethylene oxide adducts of fats and oils (such as castor oil), higher fatty acid esters of glycerol, higher fatty acid esters of pentaerythritol, sorbitol and sol Higher fatty acid esters of tan, higher fatty acid esters of sucrose, alkyl (C8-20) ethers of polyhydric alcohols, higher fatty acid amides of alkanolamines and the like]; cationic surfactants [eg higher alkylamines (laurylamine) Acetate, such as lauryl dimethylamine, alkyl (C10-20)
Trimethylammonium chloride, alkyl (10 to 20 carbon atoms) dimethylbenzylammonium chloride); amphoteric surfactant [alkyl (10 to 2 carbon atoms)
0) alkali metal salts of aminopropionic acid, alkyl (C10-20) dimethyl betaine, etc.); and mixtures of two or more of these. When used in combination, the amount of (B3) used is usually 40% by weight or less, preferably 20% by weight or less based on the total amount of the emulsifier.

The average HL of the emulsifier (B) used in the present invention
B is usually 4 to 13, preferably 6 to 12. By setting the average HLB within the above range, an aqueous dispersion having good stability can be obtained. Here, the HLB is a value obtained by the following equation described in "Oda-Teramura Co-authored," Synthesis and Application of Surfactants ", page 501, published by Maki Shoten (1957)". HLB = inorganic / organic xk (k is a constant about 10)

The amount of (B) used is usually 2 to 30 parts, preferably 5 to 25 parts, per 100 parts by weight of (A). If the amount is less than 2 parts by weight, the stability of the aqueous dispersion becomes poor,
If it exceeds 30 parts by weight, the amount of fuzz generated by the glass fibers tends to increase.

The method of dispersing (A) in water is not particularly limited. For example, (A) and (B) are preliminarily mixed, and water is gradually dropped into the mixture to cause phase inversion; A method in which water in which (B) is dissolved is gradually dropped and dispersed in A); a method in which a mixture of (A) and (B) is previously mixed is dropped and dispersed in water; A method in which (A) is dropped and dispersed in water; a method in which (A), (B) and water are mixed and dispersed at once. Among these, the methods (1) and (2) avoid the reaction between the OH group in (B) and the isocyanate group in (A) while dispersing (A) in water, and provide a good aqueous dispersion. Is preferred.

The apparatus for dispersing (A) in water is not particularly limited, but examples thereof include an anchor-type stirring method, a gear-type stirring method, a stator-rotor method, a high-pressure impact method, and an ultrasonic impact method. Can be

As the chain extender used for obtaining the aqueous polyurethane polyurea resin by extending the chain of (A) in water, water-soluble polyamines (ethylenediamine, hexamethylenediamine, isophoronediamine, diethylenetriamine, etc.), hydrazine derivatives (Hydrazine, carbodihydrazide, adipic dihydrazide, etc.), water and a combination of two or more of these. When a polyamine is used as a chain extender, the amount used is (A)
The amount is usually not more than 1 equivalent, preferably 0.2 to 0.8 equivalent, based on the isocyanate group. In the case where an organic solvent is used in the prepolymerization reaction,
After the chain extension, the solvent is removed from the aqueous dispersion by a distillation method or the like. The solid concentration of the aqueous polyurethane polyurea resin dispersion thus obtained is usually 10
-60% by weight, preferably 20-55% by weight.

The urea group (—NHCONH—) content in the polyurethane polyurea resin is usually 0.5 to
It is 8% by weight, preferably 0.7 to 6% by weight. By setting the urea group content within the above range, excellent fluffing suppression can be obtained.

If necessary, other known sizing agents may be used in combination with the sizing agent of the present invention comprising an aqueous dispersion of the polyurethane polyurea resin. Examples of the other sizing agent include starch, modified starch, dextrin, amylose, gelatin, carboxymethylcellulose, polyvinyl alcohol, polyvinylpyrrolidone, polyvinyl acetate, aqueous polyester, aqueous epoxy resin, and aqueous polyacrylate. When used in combination, the ratio of the sizing agent of the present invention to other sizing agents is not particularly limited, but is usually 10:90 to 100: 0, preferably 50:50 to 100: 0 in terms of resin weight ratio.

The sizing agent of the present invention may contain, if necessary, known additives [silane coupling agents (γ-aminopropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, vinyltrichlorosilane, vinyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, a lubricant (eg, a fatty acid amide), an antistatic agent, a plasticizer, an antifoaming agent, etc.].
The addition amount of these additives is usually 20 parts by weight or less per 100 parts by weight of the sizing agent (resin content).

The method of adhering the sizing agent of the present invention to glass fibers may be a conventional method. For example, the sizing agent is diluted with water or the like to a solid content of 1 to 10% by weight, and then coated with a roller. For example, a method of applying to a glass fiber by a method such as spray coating or impregnating coating, followed by drying with hot air at 50 to 100 ° C. and adhering, if necessary, can be exemplified. The amount (solid content) of the sizing agent is usually 0.1 to 10% by weight based on the weight of the glass fiber.

The glass fiber provided with the sizing agent as a primary sizing agent and / or a secondary sizing agent is processed into a form such as roving, yarn, chopped strand mat, continuous strand mat, cloth, etc. It is molded into a composite material as a reinforcing material for a thermosetting resin such as a resin or an epoxy resin, or a thermoplastic resin such as a polyamide resin, a polyolefin resin, or an ABS resin, and is used for electric parts, housing members, automobile parts, and the like.

[0028]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.
In the following, “part” indicates “part by weight” and “%” indicates “% by weight”.

Production Example 1 100 parts of polyneopentyl adipate diol (number average molecular weight: 1,000, melting point: about 0 ° C.) and 34 parts of isophorone diisocyanate were reacted at 90 ° C. for 4 hours, and the isocyanate group (NCO) content was 3.3%. Was obtained. This was cooled to 30 ° C., and 17 parts of styrene (7 mol) cumylphenol added with 20 mol of EO (HLB7.9) as an emulsifier and polypropylene glycol (number average molecular weight 2,000)
0) to which 11.5 mol of EO was added (number average molecular weight 2,500, oxyethylene content 20%, HLB 6.
9) 10 parts (average HLB 7.9 of emulsifier) and 30 parts of water were simultaneously added, and the mixture was sufficiently mixed and dispersed with a homomixer. Then, the mixture was further diluted with 200 parts of water.
A water extension reaction was performed at 5 ° C. for 5 hours to obtain an aqueous polyurethane polyurea resin [1] having a solid content of 41% and a urea group content of 2.3% in the resin.

Production Example 2 100 parts of poly-3-methylpentane adipate diol (number average molecular weight: 2,000, melting point: about -40 ° C.)
20 parts of 4′-dicyclohexylmethane diisocyanate was reacted at 120 ° C. for 6 hours to obtain an isocyanate group-terminated prepolymer having an NCO content of 1.8%. 30 ℃
And added 25 mol EO to styrene (5 mol) cumylphenol as an emulsifier (HLB
10.0) 8 parts and polypropylene glycol (number average molecular weight 1,500) added with 15 mol of EO (number average molecular weight 2,160, oxyethylene content 30%, H
LB8.9) 12 parts (average HLB of emulsifier)
Using 8), this was dissolved in 154 parts of water, and gradually added with stirring with a homomixer to sufficiently disperse.
Further, a solution obtained by dissolving 0.55 g of ethylenediamine in 50 g of water was gradually dropped, and a chain extension reaction was carried out.
%, An aqueous polyurethane polyurea resin [2] having a urea group content of 0.9% in the resin was obtained.

Production Example 3 100 parts of poly-3-methylpentane adipate diol (number average molecular weight 3000, melting point about -40 ° C.) and 11.2 parts of hexamethylene diisocyanate were reacted at 100 ° C. for 3 hours to give an NCO content of 2.5. % Of an isocyanate group-terminated prepolymer was obtained. This was cooled to 30 ° C., and styrene (7 mol) cumylphenol was added as an emulsifier to E.
4 parts obtained by adding 25 moles of O (HLB 8.8), and 10 moles of EO added to polypropylene glycol (number average molecular weight: 1,700) (number average molecular weight: 2,14)
0, oxyethylene content 20%, HLB 8.2) 5 parts and nonylphenol ethylene oxide 30 mol adduct (HLB 16.1) 6 parts (average H of emulsifier)
LB10.7) and water (40 parts) were added simultaneously and thoroughly mixed and dispersed with a homomixer, followed by dilution with water (100 parts),
Further, a solution obtained by dissolving 0.83 part of ethylenediamine in 50 parts of water was gradually dropped, and a chain extension reaction was carried out.
%, An aqueous polyurethane polyurea resin [3] having a urea group content of 4.1% in the resin.

Comparative Production Example 1 Polybutylene adipate diol (number average molecular weight 1,0
(00, melting point: about 50 ° C.) and 34 parts of isophorone diisocyanate were reacted at 90 ° C. for 4 hours to obtain an isocyanate group-terminated prepolymer having an NCO content of 3.3%.
This was cooled to 30 ° C., and polyoxyethylene (number average molecular weight 400) monostearate (H
LB 11.6) 4 parts of EO to 10 parts and nonylphenol
25 parts by mol (HLB9.7) (emulsifier,
HLB 10.2) and 40 parts of water were added simultaneously and thoroughly mixed and dispersed with a homomixer.
Diluted with 5 parts, and further subjected to a water extension reaction at 60 ° C. for 5 hours.
An aqueous polyurethane polyurea resin resin [A] for comparison having a solid content of 40% and a urea group content of 2.3% in the resin was obtained.

Comparative Production Example 2 100 parts of poly-3-methylpentane adipate diol (number average molecular weight: 2,000, melting point: about -40 ° C.) and 11 parts of tolylene diisocyanate were reacted at 70 ° C. for 4 hours.
An isocyanate terminated prepolymer having an NCO content of 2.6% was obtained. This is cooled to 30 ° C, and as an emulsifier,
Nonylphenol with 4 moles of EO added (HLB
9.7) Using 12 parts of polyoxyethylene (number average molecular weight 400) monostearate (HLB 11.6) 18 parts (average HLB 10.8 of emulsifier), and dissolving them in 217 parts of water, Add and mix with stirring with a mixer, and then gradually add 212 parts of water with stirring to sufficiently disperse the mixture and allow it to undergo a water extension reaction at 40 ° C. for 4 hours. The solid content is 40%, and the urea group content in the resin. 0.
An aqueous polyurethane polyurea resin [B] for comparison was obtained.

Examples 1 to 5 and Comparative Examples 1 and 2 According to the formulations shown in Table 1, a sizing agent for glass fibers of the present invention and a sizing agent for glass fibers for comparison were prepared.

[0035]

[Table 1] (Note) Polyvinyl alcohol [“GL-05”; manufactured by Nippon Synthetic Chemical Co., Ltd.]

Performance Test Examples Each of the glass fiber sizing agents of Examples 1 to 5 and Comparative Examples 1 and 2 was applied to 400 glass fiber filaments (fiber diameter 13 μm) using a roller, bundled, and tied. The amount of fluff generated per 6,000 m when wound as a roving was measured, and the fluff suppression power was evaluated. The smaller the amount of generated fluff, the better the fuzz suppression power.

[0037]

[Table 2]

[0038]

The sizing agent for glass fibers of the present invention is much more excellent in fuzz suppression power than the conventional one. The glass fiber processed product (roving, yarn, chopped strand mat, continuous strand mat, cloth, etc.) obtained by using the sizing agent of the present invention because of the above-mentioned effects is particularly suitable for various thermosetting resins or thermoplastic resins. It is extremely useful as a reinforcing material or the like.

Claims (4)

(57) [Claims] 1. An isocyanate-terminated urethane derived from a polyester polyol (A1) having a number average molecular weight of 500 to 4,000 and, if necessary, a low molecular polyol (A2) and an excess of an aliphatic polyisocyanate (A3). Dispersing the prepolymer (A) in water in the presence of a polyoxyalkylene ether (B1) of a polycyclic phenol or an emulsifier (B) comprising the (B1) and a polyoxyethylene ether (B2) of polypropylene glycol; A sizing agent for glass fibers, comprising an aqueous dispersion of a polyurethane polyurea resin obtained by chain extension with water or a polyamine. 2. The glass fiber bundle according to claim 1, wherein the polycyclic phenol constituting (B1) is at least one selected from styrenated phenol, styrenated cumylphenol and α-methylstyrenated phenol. Agent. 3. The sizing agent for glass fibers according to claim 1, wherein the average HLB of (B) is 4 to 13. 4. The sizing agent for glass fibers according to claim 1, wherein the urea group (—NHCONH—) content in the polyurethane polyurea resin is 0.5 to 8% by weight.