JP5275112B2 - Binder for glass chopped strand mat - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a binder which gives a glass chopped strand mat having a necessary and uniform strength and ductility (flexibility) by improving chopping efficiency in mechanical crushing of a binder resin and controlling the particle size distribution of the binder. <P>SOLUTION: A binder for glass chopped strand mat (C) comprises a polyester resin (A) having a solubility parameter (&alpha;) (hereinafter referred to as an "SP value") satisfying the relational expression (1): 0.2&le;¾(&alpha;)-(&beta;)¾&le;3.0, and a powder of a melted mixture of a thermoplastic resin (B) having SP value (&beta;). <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a powdery binder for glass chopped strand mats. More specifically, while improving the production efficiency when the binder resin is pulverized, the mat strength (mechanical strength such as tensile strength, the same applies hereinafter) can be maintained even if the amount of the binder is reduced compared to the conventional one, and this makes it flexible. The present invention relates to a powdery binder for glass chopped strand mats capable of producing a simple mat.

The glass chopped strand mat is usually obtained by the following method.
(1) A glass strand is obtained by bundling several 10 to several hundred glass single fibers (fiber diameter of about 10 μm) with a sizing agent.
(2) The glass strand is cut into a predetermined length to obtain a bundle of glass chopped strands.
(3) The glass chopped strands are randomly distributed in directions on the transfer net to form a laminate.
(4) The binder powder is sprayed on the laminate and heated in an oven chamber to bond the glass chopped strands with a binder to obtain a glass chopped strand mat.
As for this binder, conventionally, many unsaturated polyester resins pulverized by mechanical pulverization have been used (for example, Patent Document 1). In order to use them as they are, the distribution of particle size (sometimes referred to as the particle size in the following) is too wide and biased toward the coarse particles, so that it is most suitable for being applied to the glass chopped strand mat after pulverization. It is usually sieved to a volume average particle size of 150 to 250 μm.

JP 2003-48255 A

  However, the amount of binder obtained by sieving is not sufficient in yield, the production efficiency is poor, and the conventional binder has a wide particle size distribution range, so that all of the particles are suitable for adhesion to the laminate of glass chopped strands. Do not mean. In other words, particles having a particularly small particle diameter are less likely to adhere only to the surface layer of the laminate and reach the inner and back layers even when dispersed on the laminate, and as a result, the entire glass fiber. Insufficient binding and the resulting mat is hard and the quality of the mat is impaired; on the other hand, particularly large particles may fall through the gaps of the laminate without adhering to the laminate. As a result, there has been a drawback that the binder must be supplied in excess of the required amount in view of performance such as the strength of the original mat.

  The object of the present invention is to improve the grinding efficiency during mechanical grinding of the binder resin and control the particle size distribution of the binder by mixing thermoplastic resins having different solubility parameters in advance with a binder made of polyester resin. Therefore, it is providing the binder which gives the glass chopped strand mat which has required and uniform intensity | strength and flexibility (flexibility).

The inventors of the present invention have reached the present invention as a result of intensive studies to achieve the above object. That is, the present invention provides a melt of a polyester resin (A) having a solubility parameter (hereinafter referred to as SP value) (α) and a thermoplastic resin (B) having an SP value (β) satisfying the following relational expression (1). It is a binder (C) for glass chopped strand mats containing powder of the mixture.

0.2 ≦ | (α) − (β) | ≦ 3.0 (1)

The glass chopped strand mat binder of the present invention has the following effects.
(1) Coarse particles are less likely to be produced at the time of mechanical pulverization, and the productivity at the time of binder powder production is excellent.
(2) A uniform strength can be imparted to the glass chopped strand mat.
(3) Uniform strength can be imparted to the glass chopped strand mat with a smaller amount than in the past.
(4) A glass chopped strand mat having excellent workability such as excellent formability (flexibility) of the mat to the mold during FRP molding is provided.

[Binder for glass chopped strand mat (C)]
The binder for glass chopped strand mats (C) of the present invention comprises a polyester resin (A) and a thermoplastic resin (B), and has solubility parameters (hereinafter referred to as SP values) (α) and SP values (β). The following relational expression (1) is satisfied.

0.2 ≦ | (α) − (β) | ≦ 3.0 (1)

Furthermore, it is preferable to satisfy the following relational expression (1 ′) from the viewpoint of the stability of the resin and the grinding efficiency.

0.4 ≦ | (α) − (β) | ≦ 2.0 (1 ′)

Here, the SP value is calculated by the following formula (2) by the Fedors method described in “Polymer Engineering and Science, February, 1974, Vol. 14, No. 2, Robert F. Fedors” (pages 147 to 154). Value (denoted by δ in this document).

SP value (δ) = (ΔH / V) × 1/2 (2)

In the formula, ΔH represents the heat of molar evaporation (cal), and V represents the molar volume (cm ³ ). Further, as ΔH and V, the sum of molar evaporation heat (ΔH) and the sum of molar volumes (V) of atomic groups described in pages 151 to 153 of the above-mentioned document can be used.
Differences in SP values are indicators of compatibility between resins, such that those with close SP values are easy to mix with each other, and those with a distant numerical value are not compatible with each other because of low compatibility. .

  As described later, the binder (C) of the present invention is produced by melt-mixing a polyester resin (A) and a thermoplastic resin (B), pulverizing by mechanical pulverization after cooling, and further screening powder particles. In the production, if the value of | (α) − (β) | is less than 0.2, the polyester resin (A) and the thermoplastic resin (B) are compatibilized by melt mixing. When the binder powder is produced, the pulverization efficiency is deteriorated. As a result, the particle size distribution is biased toward the coarse particles, and the yield is lowered in sieving to obtain a volume average particle size of 100 to 250 μm as a binder. On the other hand, a value of | (α) − (β) | exceeding 3.0 is not preferable because phase separation occurs during melting and / or cooling.

In the present invention, when the polyester resin (A) is composed of two or more kinds of polyester resins, the arithmetic average of the SP values of the respective polyester resins is set to the SP value (α) of (A), and the thermoplastic resin ( Similarly, when B) is made of two or more types of thermoplastic resins, the arithmetic average of the SP values of the respective thermoplastic resins is defined as the SP value (β) of the thermoplastic resin (B).
Since the thermoplastic resin (B) includes a polyester resin as described later, the polyester resin (A) in the present invention is also included. That is, as long as the relational expression (1) is satisfied, there is no problem even if the thermoplastic resin (B) is the polyester resin (A) in the present invention in the combination of (A) and (B).

  The SP value of the polyester resin (A) is preferably 9.5 to 13.5, and the SP value of the thermoplastic resin (B) is preferably 8 to 16.

The glass chopped strand mat binder (C) of the present invention comprises a polyester resin (A) and a thermoplastic resin (B). (C) preferably further has a volume-based particle size and volume-based particle size distribution in a certain region.
Specifically, the volume average particle diameter D _V of (C) is a uniform strength of the glass chopped strand mat obtained, flexibility, and the binder amount, preferably from the viewpoint of the mat strength 100 to 250 [mu] m, more preferably 110 It is -230 micrometers, Most preferably, it is 120-220 micrometers.

  The proportion of the particles having a volume reference particle diameter of 300 μm or more in (C) is preferably 20% by weight or less, more preferably 15% by weight from the viewpoint of the amount of binder used and the point of adhesion between the glass chopped strand laminate and the binder. In the following, particularly preferably 10% by weight or less; the proportion of particles having a volume-based particle size of 100 μm or less is preferably 20% by weight or less from the viewpoints of dust suppression and the uniform strength and flexibility of the glass chopped strand mat. More preferably, it is 15 weight% or less, Most preferably, it is 10 weight% or less.

The variation coefficient C _v of the particle size distribution on a volume basis of (C) is preferably 0.1 to 30 percent in view of the adhesion efficiency of the binder in the productivity and laminate, more preferably 1 to 28%, Especially preferably, it is 10 to 25%. The variation coefficient _Cv is obtained by the method described later.

Here, the volume average particle diameter D _v , the volume reference particle diameter, and the coefficient of variation C _v can all be obtained by a laser diffraction scattering method. As a measuring apparatus, for example, a particle size distribution measuring instrument [“Microtrack 9320 HRA particle size analysis” Total ”, manufactured by Nikkiso Co., Ltd.].

[Polyester resin (A)]
Examples of the polyester resin (A) as the main component in the present invention include polycondensates of polycarboxylic acid (a1) and low molecular polyol (a2), and compound (a3) having a carboxyl group and a hydroxyl group in the same molecule. Self-polycondensate, ring-opening polycondensate of lactone (a4) and the like can be mentioned.

The polycarboxylic acid (a1) includes not only the polycarboxylic acid itself but also an ester-forming derivative thereof.
Specific examples of the polycarboxylic acid (a1) include aliphatic polycarboxylic acids [functional group number 2-6, carbon number (hereinafter abbreviated as C) 3-30, such as succinic acid, glutaric acid, maleic acid, fumaric acid, adipine. Acid, azelaic acid, sebacic acid, hexahydrophthalic acid, etc.], aromatic polycarboxylic acid (functional number 2-6, C8-30, for example, phthalic acid, isophthalic acid, terephthalic acid, tetrabromophthalic acid, tetrachlorophthalic acid , Trimellitic acid, pyromellitic acid, etc.), alicyclic-containing polycarboxylic acid (functional number 2-6, C6-50, such as 1,3-cyclobutanedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 1,2- And 1,4-cyclohexanedicarboxylic acid, 1,3- and 1,4-dicarboxymethylcyclohexane, dicyclohexyl-4,4′-dicarbo Acid and dimer acids, etc.); ester-forming derivatives of these polycarboxylic acids [acid anhydrides (eg, maleic anhydride, phthalic anhydride, etc.), lower alkyl (C1-4) esters (dimethyl esters, diethyl esters, etc.) (For example, dimethyl terephthalate), acid halide (acid chloride, etc.)]; and a mixture of two or more thereof. Of these, aliphatic polycarboxylic acids are preferable from the viewpoint of preventing coloring of the polyester resin.

The low molecular polyol (a2) is a number average molecular weight per hydroxyl group [hereinafter abbreviated as Mn. The measurement is based on a gel permeation chromatography (GPC) method. ] Is less than 300 (preferably a molecular weight of 31 or more and Mn 250 or less), and a divalent to 10-valent or higher (preferably 2-3) polyol can be used.
Examples of (a2) include dihydric alcohol (a21), trivalent to 10-valent or higher polyhydric alcohol (a22), and alkylene oxides of these alcohols or polyvalent (divalent to trivalent or higher) phenols ( Hereinafter, abbreviated as AO, C2 to 10) low molar (1 to 10) adduct (a23); and mixtures of two or more of these.

  As AO, ethylene oxide (hereinafter abbreviated as EO), propylene oxide (hereinafter abbreviated as PO), 1,2-, 1,3- and 2,3-butylene oxide, tetrahydrofuran (hereinafter abbreviated as THF), styrene oxide, C5-10 or more α-olefin oxide, epichlorohydrin; and combinations of two or more thereof (block and / or random addition). Among these AOs, EO, PO, and combinations thereof are preferable from the viewpoint of mat strength and permeability of the styrene monomer or the like to the mat in application of the mat to glass fiber reinforced plastic (FRP).

  Specific examples of the dihydric alcohol (a21) include aliphatic alcohol [linear alcohol [ethylene glycol, diethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6- Hexanediol (hereinafter abbreviated as EG, DEG, 1,3-PG, 1,4-BD, 1,5-PD, 1,6-HD)], branched chain alcohol [1,2-propylene glycol, Neopentyl glycol (hereinafter abbreviated as 1,2-PG and NPG, respectively), 3-methyl 1,5-pentanediol, 2,2-diethyl-1,3-propanediol, 1,2-, 1,3- and 2,3-butanediol etc.]; and an alcohol having a ring [alicyclic ring-containing alcohol [1,4-bis (hydroxymethyl) cyclohexa Etc.], araliphatic alcohols (m-and p- xylylene glycol and the like) and the like] and the like.

  Specific examples of the trivalent to 10-valent or higher polyhydric alcohol (a22) include alkane polyols [C3 to 10 such as glycerin, trimethylolpropane, pentaerythritol, sorbitol (hereinafter referred to as GR, TMP, PE, SO, respectively). Abbreviation), etc.], intermolecular or intramolecular dehydrates of the alkane polyol [diPE, polyGR (polymerization degree 2-8), sorbitan, etc.], saccharides and derivatives thereof (glycosides) (sucrose, methylglucoside, etc.) Is mentioned. Of the above (a21) and (a22), aliphatic alcohols are preferable from the viewpoint of mat strength, and 1,4-BD and NPG are more preferable.

Specific examples of the (a23) include the AO low molar adducts of the above (a21) and (a22), and the AO low molar adduct of polyvalent (divalent to trivalent or higher) phenol having a ring. It is done.
The polyhydric phenol includes C6-18 dihydric phenol, such as monocyclic dihydric phenol (hydroquinone, catechol, resorcinol, urushiol, etc.), bisphenol (bisphenol A, -F, -C, -B, -AD and -S, dihydroxybiphenyl, 4,4'-dihydroxydiphenyl-2,2-butane, etc.), and condensed polycyclic dihydric phenols [dihydroxynaphthalene (eg, 1,5-dihydroxynaphthalene), binaphthol, etc.]; Octavalent or higher polyhydric phenols such as monocyclic polyphenols (pyrogallol, phloroglucinol, and mono- or dihydric phenols (phenol, cresol, xylenol, resorcinol, etc.) aldehydes or ketones (formaldehyde, glutaraldehyde) , Guri Oxal, acetone) low condensates (eg phenol or cresol novolak resin, resole intermediate, polyphenol obtained by condensation reaction of phenol and glyoxal or glutaraldehyde, and polyphenol obtained by condensation reaction of resorcin and acetone) .

  Specific examples of the compound (a3) having a carboxyl group and a hydroxyl group in the same molecule include C2-10, such as lactic acid, glycolic acid, β-hydroxybutyric acid, hydroxypivalic acid, hydroxyvaleric acid, and two or more thereof. Of the mixture.

  Examples of the lactone (a4) include those having C4 to 15 (preferably C6 to 12), such as ε-caprolactone, γ-butyrolactone, and γ-valerolactone.

  Of the above polyester resins, preferred are polycondensates of polycarboxylic acid (a1) and low molecular polyol (a2), from the viewpoint of rapid polycondensation reaction and permeability of styrene and the like into the mat, Preferred is a polycondensation product of a polycarboxylic acid and an AO adduct of a polyvalent hydroxyl group-containing compound having a ring, and particularly preferred is an AO low mole of an aliphatic polycarboxylic acid and a polyhydric phenol or araliphatic alcohol having a ring. It is a polycondensate with an adduct.

The reaction temperature during the polycondensation is not particularly limited, but is usually 100 to 300 ° C, preferably 130 to 220 ° C. The polycondensation reaction is usually performed under normal pressure or reduced pressure (for example, 133 Pa or less). Moreover, it is desirable to perform this reaction in the atmosphere of inert gas, such as nitrogen gas, from a viewpoint of coloring prevention of a polyester resin.
The reaction equivalent ratio (carboxyl group / hydroxyl group equivalent ratio) of (a1) and (a2) during the polycondensation reaction is preferably from the viewpoint of rapid polycondensation reaction and stability of physical properties of the resulting polyester resin. It is 9 to 1.4, more preferably 0.9 to 1.2. The acid value of the polyester resin after the production is preferably 20 or less, more preferably 0 to 15 from the viewpoint of water resistance.

The condensation reaction may be either no catalyst or using an esterification catalyst.
Examples of esterification catalysts include protonic acids (phosphoric acid, etc.), metals (alkali metals, alkaline earth metals, transition metals, 2B, 4A, 4B and 5B metals), carboxylic acid (C2-4) salts, carbonic acid Examples include salts, sulfates, phosphates, oxides, chlorides, hydroxides, alkoxides, and the like.
Of these, preferred from the viewpoint of reactivity are the carboxylic acid (C2-4) salts, oxides, alkoxides and products of the 2B, 4A, 4B and 5B metals, and more preferred from the viewpoint of low coloration of the product. Antimony oxide, monobutyltin oxide, tetrabutyl titanate, tetrabutoxy titanate, tetrabutyl zirconate, zirconyl acetate, and zinc acetate.
The amount of the esterification catalyst used is not particularly limited as long as a desired molecular weight can be obtained, but the reactivity and low colorability of the esterification catalyst are based on the total weight of the polycarboxylic acid (a1) and the low molecular polyol (a2). From the viewpoint, it is preferably 0.005 to 3%, more preferably 0.01 to 1%.

  In order to accelerate the reaction, an organic solvent can be added and refluxed. After completion of the reaction, the organic solvent is removed. The organic solvent is not particularly limited as long as it does not have active hydrogen such as a hydroxyl group. For example, hydrocarbon (toluene, xylene, etc.), ketone (methyl ethyl ketone, methyl isobutyl ketone, etc.), ester (ethyl acetate, Butyl acetate).

  The self-polycondensation reaction of the compound (a3) having a carboxyl group and a hydroxyl group in the same molecule and the ring-opening polymerization reaction of the lactone (a4) are carried out by the polycarboxylic acid (a1) and the low molecular polyol (a2). It can carry out according to the conditions in the polycondensation reaction.

  The weight average molecular weight of the polyester resin (A) in the present invention [hereinafter abbreviated as Mw. The measurement is based on the GPC method. ] And Mn are preferably 5,000 to 50,000, more preferably 10,000 to 45,000, and Mn is preferably 400 to 4,500 from the viewpoint of the strength and flexibility of the glass chopped strand mat. More preferably, it is 800-4,000.

  The softening point of the polyester resin by the ring-and-ball method (JIS K2207, “Petroleum Asphalt” “6.4 Softening Point Test Method”, the same shall apply hereinafter) indicates that the glass chopped strand mat does not exhibit stickiness and is easy to work after processing. From the viewpoint of the above, and from the viewpoint of the bondability between the glass chopped strands by the binder, it is preferably 80 to 150 ° C, more preferably 90 to 140 ° C.

  Glass transition temperature of the polyester resin (A) by differential thermal analysis (hereinafter abbreviated as Tg; measurement conforms to JIS K7121, “Method of measuring plastic transition temperature”) is used to prevent blocking during storage of the binder and glass chopped strand mat. From the viewpoint of workability in post-processing, the temperature is preferably 40 to 60 ° C, more preferably 45 to 55 ° C.

The polyester resin (A) in the present invention can be usually produced as follows.
First, the above-mentioned alcohol component, acid component and catalyst (dibutyltin oxide, etc.) are charged into a reaction vessel equipped with a cooling tube, a stirring rod, a thermometer and a nitrogen introduction tube, and heated under a nitrogen atmosphere, usually 150 to After reacting at 170 ° C. for 4 to 6 hours while confirming the acid value, the acid value (unit: mgKOH / g) became 20 or less, the polyester resin (A) was removed by cooling to 180 ° C. or less and taking out. obtain.

[Thermoplastic resin (B)]
On the other hand, the type of the synthetic resin constituting the thermoplastic resin (B), which is another essential component, is not particularly limited.
Examples thereof include polyphenylene ether resin (B1), vinyl resin (B2), polyester resin (B3), polyamide resin (B4), polycarbonate resin (B5), polyacetal resin (B6), and a mixture of two or more of these. .

Specific examples of the polyphenylene ether resin (B1) include poly (2,6-dimethyl-1,4-phenylene) ether, poly (2,6-diethyl-1,4-phenylene) ether, and poly (2-methyl- 6-ethyl-1,4-phenylene) ether, poly (2-methyl-6-propyl-1,4-phenylene) ether, poly (2,6-dipropyl-1,4-phenylene) ether, poly (2- Ethyl-6-propyl-1,4-phenylene) ether, poly (2,6-dimethoxy-1,4-phenylene) ether, poly (2,6-dichloromethyl-1,4-phenylene) ether, poly (2 , 6-dibromo-1,4-phenylene) ether, poly (2,6-diphenyl-1,4-phenylene) ether, poly (2,6-dichloro-1,4-phenylene) ) Ether, poly (2,6-dibenzyl-1,4-phenylene) ether, poly (2,5-dimethyl-1,4-phenylene) ether.
Further, (B1) includes those obtained by grafting monomers of styrene and / or derivatives thereof (modified polyphenylene ether) to (B1).

  Examples of the vinyl resin (B2) include polyolefin resin (B21), polyacrylic resin (B22), and polystyrene resin (B23).

Examples of the polyolefin resin (B21) include polypropylene, polyethylene (hereinafter abbreviated as PP and PE, respectively), propylene-ethylene copolymer [copolymerization ratio (weight ratio) = 0.1 / 99.9 to 99.9 / 0. .1], copolymers of propylene and / or ethylene and one or more other α-olefins (C4-12) (random and / or block addition) [copolymerization ratio (weight ratio) = 99/1 5/95], ethylene / vinyl acetate copolymer (EVA) [copolymerization ratio (weight ratio) = 95 / 5-60 / 40], ethylene / ethyl acrylate copolymer (EEA) [copolymerization ratio (weight ratio) ) = 95 / 5-60 / 40].
Among these, PP, PE, propylene-ethylene copolymer, propylene and / or a copolymer of ethylene and one or more of C4-12 α-olefin [copolymerization ratio (weight ratio) = 90 / 10 to 10/90, random and / or block addition].

  As the polyacrylic resin (B22), for example, one or more (co) polymers of the above acrylic monomer [alkyl (C1-20) (meth) acrylate, (meth) acrylonitrile, etc.] [methyl poly (meth) acrylate, Poly (meth) butyl acrylate, etc.] and copolymers with one or more of the above-mentioned vinyl monomers copolymerizable with one or more of these monomers [acrylic monomer / vinyl monomer copolymerization ratio (weight ratio) is a resin physical property In view of the above, preferably 5/95 to 95/5, more preferably 50/50 to 90/10] [however, those included in (B21) are excluded] are included.

  As the polystyrene resin (B23), vinyl group-containing aromatic hydrocarbons alone or vinyl group-containing aromatic hydrocarbons and at least one selected from the group consisting of (meth) acrylic acid esters, (meth) acrylonitrile and butadiene Examples thereof include a copolymer as a structural unit.

Examples of vinyl group-containing aromatic hydrocarbons include C8-30 styrene and its derivatives,
For example, o-, m-, and p-alkyl (C1-10) styrene (vinyl toluene, etc.), α-alkyl (C1-10) styrene (α-methylstyrene, etc.) and halogenated styrene (chlorostyrene, etc.) can be mentioned. .
Specific examples of (B23) include polystyrene, polyvinyltoluene, styrene / acrylonitrile copolymer (AS resin) [copolymerization ratio (weight ratio) = 70/30 to 80/20], styrene / methyl methacrylate copolymer. (MS resin) [copolymerization ratio (weight ratio) = 60/40 to 90/10], styrene / butadiene copolymer [copolymerization ratio (weight ratio) = 60/40 to 95/5], acrylonitrile / butadiene / Styrene copolymer (ABS resin) [copolymerization ratio (weight ratio) = (20-30) / (5-40) / (40-70)], methyl methacrylate / butadiene / styrene copolymer (MBS resin) [Copolymerization ratio (weight ratio) = (20-30) / (5-40) / (40-70)].

  Examples of the polyester resin (B3) include aromatic ring-containing polyesters (polyethylene terephthalate, polybutylene terephthalate, polycyclohexanedimethylene terephthalate, etc.) and aliphatic polyesters (polybutylene adipate, polyethylene adipate, poly-ε-caprolactone, etc.).

As the polyamide resin (B4), a lactam ring-opening polymer (B41), a dehydration polycondensation product (B42) of a diamine and a dicarboxylic acid, a self-polycondensation product (B43) of an aminocarboxylic acid, and a poly (condensation) combination thereof are used. Examples thereof include copolymer nylon having two or more types of monomer units.
Examples of the lactam (b411) in (B41) include C6-12, such as caprolactam, enantolactam, laurolactam, and undecanolactam, and (B41) includes nylon 4, nylon 5, nylon 6, nylon 8, and nylon. 12 etc. are mentioned.
Examples of the diamine (b421) in (B42) include C6-12, such as hexamethylenediamine, heptamethylenediamine, octamethylenediamine, decamethylenediamine, and the like.
Of the dicarboxylic acids (b422), as aliphatic dicarboxylic acids (C4-20), for example, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid. , Maleic acid, fumaric acid, itaconic acid.
Aromatic (aliphatic) dicarboxylic acids include C8-20, such as ortho-, iso- and terephthalic acid, naphthalene-2,6- and -2,7-dicarboxylic acid, diphenyl-4,4'dicarboxylic acid, diphenoxy Examples include alkali metal (lithium, sodium, potassium, etc.) salts of ethanedicarboxylic acid and 3-sulfoisophthalic acid.
Examples of the alicyclic dicarboxylic acid include C7-14, such as cyclopropanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, cyclohexenedicarboxylic acid, and dicyclohexyl-4,4-dicarboxylic acid.
Among the amide-forming derivatives, examples of the acid anhydride include anhydrides of the above dicarboxylic acids, such as maleic anhydride, itaconic anhydride, and phthalic anhydride. Lower (C1-4) alkyl esters include those of the above dicarboxylic acids. Alkyl esters such as dimethyl adipate, ortho-, iso- and dimethyl terephthalate are mentioned.
Examples of (B42) include nylon 66 by condensation polymerization of hexanemethylenediamine and adipic acid, nylon 610 by polycondensation of hexamethylenediamine and sebacic acid, and the like.

As aminocarboxylic acid (b431) in (B43), C2-12, for example, glycine, alanine, valine, leucine, isoleucine, phenylalanine, ω-aminocaproic acid, ω-aminoenanthic acid, ω-aminocaprylic acid, ω-aminopergon Acid, ω-aminocapric acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid. Examples of (B43) include nylon 7 by polycondensation of aminoenanthate, nylon 11 by polycondensation of ω-aminoundecanoic acid. And nylon 12 by polycondensation of 12-aminododecanoic acid.

  In the production of (B4), a molecular weight modifier may be used, and examples of the molecular weight modifier include the dicarboxylic acids and / or diamines exemplified in (b421) and (b422). Of the dicarboxylic acids as molecular weight modifiers, preferred are aliphatic dicarboxylic acids, aromatic dicarboxylic acids and alkali metal salts of 3-sulfoisophthalic acid, and more preferred are adipic acid, sebacic acid, terephthalic acid, isophthalic acid and It is sodium 3-sulfoisophthalate. Of the diamines as molecular weight regulators, hexamethylene diamine and decamethylene diamine are preferable.

  Examples of the polycarbonate resin (B5) include bisphenols (C12-20, such as bisphenol A, -F and -S, 4,4'-dihydroxydiphenyl-2,2-butane) and dihydroxybiphenyl polycarbonates (for example, the above bisphenol and phosgene). Or a condensate with a carbonic acid diester) and alloy resins (polycarbonate / ABS alloy resin, etc.).

  Examples of the polyacetal resin (B6) include formaldehyde or trioxane homopolymers (polyoxymethylene homopolymer, etc.), and copolymers of formaldehyde or trioxane and cyclic ethers [AO (EO, PO, dioxolane, etc.)] Oxymethylene / polyoxyethylene (weight copolymer = 90/10 to 99/1 block copolymer)] and the like.

  Among these (B), from the viewpoint that the binder (C) fuses between the glass chopped strands, the vinyl resin (B2) is preferable, and the polyolefin resin (B21) and the polystyrene resin (B23) are more preferable. .

  The softening point of the thermoplastic resin (B) by the ring-and-ball method is based on the prevention of adhesiveness of the glass chopped strand mat and the viewpoint of workability in post-processing, and the fusion bonding property between the glass chopped strands by the binder (C), the mat From a viewpoint of intensity | strength, Preferably it is 80-150 degreeC, More preferably, it is 90-140 degreeC.

  Mn of (B) is preferably 400 to 4,500, more preferably 800 to 4,000 from the viewpoint of strength and flexibility of the glass chopped strand mat, and Mw is preferably 5,000 to 50, from the same viewpoint. 000, more preferably 10,000 to 45,000.

  The weight ratio of the polyester resin (A) to the thermoplastic resin (B) in the binder (C) is preferably 50/50 from the viewpoint of grinding efficiency, adhesion to the glass chopped strands, and fusion bonding between the glass chopped strands. To 99.9 / 0.1, more preferably 70/30 to 99.9 / 0.1, and particularly preferably 80/20 to 99.5 / 0.5.

[Additive (D)]
Further, the binder (C) of the present invention may be used in combination with an additive (D) such as an antiblocking agent, a lubricant, and a hydrophilicity imparting agent, if necessary. These additives (D) may be added after melting and before pulverization or after pulverization.
The total amount of (D) used is usually 8% or less, preferably 0.01 to 5%, more preferably 0.1 to 3%, based on the total weight of (A) and (B).

Examples of the anti-blocking agent (D1) include fine fatty acids or salts thereof, silicon or metal oxides, silicon or metal carbides, calcium carbonate, talc, organic resins, and mixtures thereof.
As higher fatty acids, C8-24, such as lauric acid, stearic acid;
Examples of salts of higher fatty acids include salts of alkali metals (Na, K, Li, etc.), alkaline earth metals (Ca, Ba, Mg, etc.), Zn, Cu, Ni, Co and Al of the above higher fatty acids;
Examples of silicon or metal oxides include silicon dioxide, silicon oxide, aluminum oxide, iron oxide, titanium oxide, magnesium oxide, and zirconium oxide. Examples of the carbide include silicon carbide and aluminum carbide;
Examples of the organic resin include polyolefin resin, polyamide resin, poly (meth) acrylic resin, silicon resin, polyurethane resin, phenol resin, polytetrafluoroethylene resin, and cellulose powder.
Of these, metal salts of higher fatty acids and silicon or metal oxides are preferable from the viewpoint of powder flowability.

  The amount of (D1) used is usually 5% or less based on the total weight of (A) and (B), preferably from 0.01 to 2.0 from the viewpoint of preventing blocking of the binder and binding properties of the glass fiber. Preferably it is 0.1 to 1.0%.

Examples of the lubricant (D2) include wax, low molecular weight polyethylene, higher alcohol, higher fatty acid (metal salt), higher fatty acid ester, and higher fatty acid amide.
As the wax, carnauba wax and the like; As the low molecular weight polyethylene, polyethylene of Mn 1,000 to 10,000, etc .; As the higher alcohol, C10-24, for example, stearic acid; As the higher fatty acid ester, C10-36, for example, Butyl stearate, polyhydric (2-4) alcohol AO (C2-3) adduct ester of higher fatty acid (C10-24) (monostearate of EG EO 5 mol adduct, etc.); ˜40, such as stearamide.
Among these, preferred from the viewpoint of glass fiber binding properties are higher fatty acid (C10-24) polyvalent (2-4) alcohol AO (C2-3) adduct esters and higher fatty acid amides.

  The amount of (D2) used is usually 5% or less based on the total weight of (A) and (B), preferably 0.01 to 2.0% from the viewpoint of powder flowability and glass fiber bonding, More preferably, it is 0.1 to 1.0%.

As the hydrophilicity imparting agent (D3), polyvinyl alcohol (Mn 1,000 to 100,000), carboxymethyl cellulose, sodium alginate, polyethylene glycol (hereinafter abbreviated as PEG) (Mn 200 to 20,000), PEG (Mn 100 to 2, 000) -containing organopolysiloxane (Mn 200 to 50,000), starch, sodium polyacrylate (Mn 500 to 20,000), quaternary ammonium base-containing (meth) acryloyl group-containing polymer, and the like.
Of these, PEG and PEG chain-containing organopolysiloxane are preferred from the viewpoint of glass fiber bonding.

  The amount of (D3) used is usually 5% or less based on the total weight of (A) and (B). Affinity with water sprayed on the glass chopped strand laminate described below and the viewpoint of glass fiber binding To preferably 0.01 to 2.0%, more preferably 0.1 to 1.0%.

The binder (C) of the present invention can be usually produced by the following procedure.
(1) Melt mixing The polyester resin (A) and the thermoplastic resin (B) are melted and mixed at 130 to 200 (preferably 140 to 180) ° C., and the resulting molten mixture (M) is 15 to 40 (preferably 20-30) Cool to ° C.
(2) Mechanical pulverization The cooled mixture (M) is mechanically pulverized into powder. The additive (D) is added at any stage before and / or after mechanical grinding.
(3) Screening of powder particles Powder particles are screened using a JIS standard screen (mesh 355 μm), and the powder particles that have passed through the screen are defined as a binder (C).

As a melt mixing apparatus, a plast mill [model number “Lab plast mill R type”, manufactured by Toyo Seiki Seisakusho, the same shall apply hereinafter. ], A table type kneader [model number “PBV-0.1 type”, manufactured by Irie Shokai Co., Ltd.], a small kneader [model number “LDS-50”, manufactured by Tanaka Tech Co., Ltd.], and the like.
Sample mills [model number “SK-M10”, manufactured by Kyoritsu Riko Co., Ltd.], wing mills [manufactured by Sanjo Industry Co., Ltd.], new power mills [model number “PM-2005”, Osaka Chemical Co., Ltd.] Etc.].

[Glass chopped strand mat]
The glass chopped strand mat of the present invention is composed of a glass chopped strand laminate and a binder (C) and can be produced, for example, by the following steps.
(1) A glass chopped strand laminate is obtained by spraying glass chopped strands in a directionally disordered and uniform thickness in a release-treated flat plate mold.
(2) Spray approximately the same amount of tap water as the sprayed glass chopped strands with a spray bottle so that the surface of the glass chopped strands is sufficiently wet.
(3) A predetermined amount of binder (C) is uniformly deposited.
(4) The operations of (1) to (3) are repeated 1 to 3 times or more to obtain a laminate.
(5) A glass chopped strand mat bonded with a binder is obtained by pressing with a press heated to 150 to 170 ° C.

  The binding amount of the binder based on the weight of the glass chopped strand laminate is that of the mechanical strength and handling properties of the mat (flexibility, fit to a mold when forming a glass fiber reinforced plastic molded product described later, etc.). From the viewpoint, it is preferably 1 to 30%, more preferably 3 to 25%.

The weight (g / m ² ) of the glass chopped strand mat obtained in the above (5) is preferably 50 to 600, more preferably 100 to 500 from the viewpoint of the mechanical strength and handling properties of the mat.

The difference between the maximum value and the minimum value of the tensile strength of the glass chopped strand mat is preferably less than 40N, more preferably 35N or less, and particularly preferably 30N or less, from the viewpoint of handling properties of the mat.
Here, the tensile strength is measured according to JIS R3420, which will be described later, and the difference between the maximum value and the minimum value of the tensile strength is the difference between the maximum value and the minimum value obtained for 10 test pieces. It is evaluated with.

Moreover, the glass fiber reinforced plastic molded article of the present invention is not particularly limited with respect to the molding method, and examples thereof include a hand lay-up method, a spray-up method, a preform method, a matched die method, and an SMC method. Among these, for example, the hand lay-up method is usually performed in the following procedure.
(1) A release agent is applied to the surface of the mold.
(2) Apply a matrix resin (unsaturated polyester resin or the like) at room temperature (15 to 25 ° C.) using a roller or the like so as to obtain a uniform thickness.
(3) The resin is gelled in a warm air oven adjusted to about 40 ° C.
(4) A glass chopped strand mat is fitted to the mold surface, a solution obtained by diluting the matrix resin with a styrene monomer or the like is laminated on the glass chopped strand mat with a roller or the like, and air is removed with a roller.
(5) The laminate is cured in a warm air oven.
(6) Take out from the mold to obtain a molded product.

As the matrix resin used in the molding method including the hand lay-up method, a thermosetting resin (unsaturated polyester resin, vinyl ester resin, epoxy resin, phenol resin, polyurethane resin, silicone resin, modified acrylic resin, furan resin, etc.) ) And thermoplastic resins (ABS resin, polycarbonate resin, polyethylene terephthalate resin, polyamide resin, polyetherimide resin, polyimide resin, etc.).
Among these, for example, in the case of the hand lay-up method, a thermosetting resin is used, and unsaturated polyester resins and vinyl ester resins are preferable from the viewpoint of workability during molding.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further, this invention is not limited to these. In the following, parts and% represent parts by weight and% by weight, respectively.

Production Example 1 <Production of Polyester Resin (A-1)>
Into a reaction vessel equipped with a cooling tube, a stir bar, a thermometer and a nitrogen introduction tube was charged 3,365 parts of EO 2.2 mol adduct of bisphenol A, 1,123 parts of fumaric acid, and 6 parts of dibutyltin oxide, and nitrogen was added. The reaction was carried out in an atmosphere at 180 ° C. for 4 hours. Thereafter, the temperature was raised to 200 ° C. and reacted for 5.5 hours under a reduced pressure of 3 to 4 kPa, then further raised to 210 ° C. and cooled to 180 ° C. when the acid value of the reaction product reached 16.0. To obtain a polyester resin (A-1). SP value ((alpha)) of (A-1) was 10.9, Mw30,000, Mn2,800, Tg53 degreeC, and the softening point 116 degreeC.

Production Example 2 <Production of Melt Mixture (M-1)>
(A-1) 40 parts and polystyrene resin (B-1) ["Himmer ST-120", trade name, manufactured by Sanyo Chemical Industries, SP value (β) is 10.6, Tg is 61 ° C, softening The point is 120 ° C., and so on. ] 10 parts plast mill [model number "Lab plast mill R type", manufactured by Toyo Seiki Seisakusho, the same below. ] Was melt-kneaded at 130 ° C. for 10 minutes to obtain a molten mixture (M-1).

Production Example 3 <Production of Melt Mixture (M-2)>
(A-1) 40 parts and polyethylene resin (B-2) [“J-REX LD J40”, trade name, manufactured by Nippon Polyolefin Co., Ltd., SP value (β) is 8.1, Tg is −120 ° C., The softening point was 107 ° C.] 10 parts were melt kneaded at 150 ° C. for 10 minutes with a plast mill to obtain a molten mixture (M-2).

Production Example 4 <Production of Melt Mixture (M-3)>
45 parts of (A-1) and 5 parts of (B-1) were melt kneaded at 130 ° C. for 10 minutes with a plast mill to obtain a molten mixture (M-3).

Production Example 5 <Production of Molten Mixture (M-4)>
30 parts of (A-1) and 20 parts of (B-2) were melt kneaded at 150 ° C. for 10 minutes using a plast mill to obtain a molten mixture (M-4).

Comparative Production Example 1 <Production of Molten Mixture (Ratio M-1)>
(A-1) 40 parts and ethylene / vinyl acetate copolymer (B-3) [“J-REX EVA BM05-80”, trade name, manufactured by Nippon Polyolefin Co., Ltd., SP value (β) is 10.8 , Tg is −80 ° C., softening point is 103 ° C.] 10 parts are melt-kneaded at 150 ° C. for 10 minutes using a plast mill to obtain a molten mixture (ratio M-1).

Example 1
The molten mixture (M-1) was mechanically pulverized at 12,500 rpm for 3 minutes using a sample mill [model number “SK-M10”, manufactured by Kyoritsu Riko Co., Ltd.], and the resulting resin powder was sieved with an opening of 355 μm. The powder which passed through the sieve and the binder (C-1) were obtained. The yield at this time was 82%.

Example 2
A binder (C-2) was obtained in the same manner as in Example 1 except that the molten mixture (M-1) was replaced with the molten mixture (M-2). The yield at this time was 75%.

Example 3
A binder (C-3) was obtained in the same manner as in Example 1 except that the molten mixture (M-1) was replaced with the molten mixture (M-3). The yield at this time was 100%.

Example 4
A binder (C-4) was obtained in the same manner as in Example 1 except that the molten mixture (M-1) was replaced with the molten mixture (M-4). The yield at this time was 74%.

Comparative Example 1
A binder (C′-1) was obtained in the same manner as in Example 1 except that the molten mixture (M-1) was replaced with a molten mixture (ratio M-1). The yield at this time was 58%.

Comparative Example 2
A binder (C′-2) was obtained in the same manner as in Example 1 except that the molten mixture (M-1) was replaced with the polyester resin (A-1). The yield at this time was 65%.

Example 5
Glass strands for glass chopped strands (average strand count 30 tex, glass fiber density 2.5 g / cm ³ ) were cut using a glass chopper [manufactured by Togiken Co., Ltd.] to obtain a 2-inch long glass chopped strand. .
The glass chopped strand 22g is uniformly dispersed and laminated so that the direction becomes disordered in a 25 cm × 40 cm × 3 cm flat plate mold subjected to the mold release treatment, and then the surface of the laminated body of the glass chopped strand is wetted. Tap water was sprayed with a spray bottle.
Next, 0.825 g of binder (C-1) corresponding to 3.75% of the weight of the glass chopped strand laminate was uniformly sprayed on the laminate. This operation was repeated once to form a laminate having a two-layer structure in which 1.65 g of a binder equivalent to 3.75% of the total weight of glass chopped strands was uniformly sprayed.
The laminate was placed in a circulating dryer at 200 ° C. for 3 minutes together with the mold, and then pressed for 1 minute with a roll press heated to 170 ° C., resulting in a thickness of 1.2 mm and loss on ignition (described later) 3 A 60% by weight glass chopped strand mat (GM-1) was obtained.

Example 6
A glass chopped strand mat (GM-2) having a thickness of 1.2 mm and an ignition loss of 3.50% by weight, except that the binder (C-1) was replaced with (C-2). )

Example 7
A glass chopped strand mat (GM-3) having a thickness of 1.2 mm and an ignition loss of 3.50% by weight, except that the binder (C-1) was replaced with (C-3). )

Example 8
A glass chopped strand mat (GM-4) having a thickness of 1.2 mm and a loss on ignition of 3.45% by weight was obtained in the same manner as in Example 5 except that the binder (C-1) was replaced with (C-4). )

Comparative Example 3
A glass chopped strand mat (GM ′) having a thickness of 1.2 mm and an ignition loss of 3.25% by weight, except that the binder (C-1) was replaced with (C′-1). -1) was obtained.

Comparative Example 4
A glass chopped strand mat (GM ′) having a thickness of 1.2 mm and a loss on ignition of 3.35 wt% was obtained in the same manner as in Example 5 except that the binder (C-1) was replaced with (C′-2). -2) was obtained.

  The evaluation of the obtained binder and glass chopped strand mat was performed according to the following method. The results are shown in Tables 1 and 2.

<Evaluation items>
(1) Softening point (° C)
Measured with an automatic softening point tester [equipment name “ASP-5”, manufactured by Tanaka Scientific Instruments Manufacturing Co., Ltd.] in accordance with “6.4 Softening Point Test Method (Ring and Ball Method)” of JIS K2207 “Petroleum Asphalt” did.

(2) Glass transition temperature (Tg) (° C)
In accordance with JIS K7121 “Plastic Transition Temperature Measurement Method”, the measurement was performed according to [device name “RDC-220”, manufactured by Seiko Denshi Kogyo Co., Ltd.].

(3) Volume average particle diameter (D _V ) (μm) of the binder powder, ratio of each particle having a volume reference particle diameter of 300 μm or more and 75 μm or less in all particles of the powder (% by weight)
It was measured by a laser diffraction / scattering method using a “Microtrack 9320 HRA particle size analyzer” [device name, manufactured by Nikkiso Co., Ltd.].
(4) Coefficient of variation of volume-based particle size distribution (C _V ) (%)
The coefficient of variation (C _V ) is a value calculated from the following formula, and the standard deviation and volume average particle diameter (D _V ) are measured by a laser diffraction scattering method using a “Microtrack 9320 HRA particle size analyzer”. did.

Coefficient of variation (C _V ) = [standard deviation / volume average particle diameter (D _V )] × 100

(5) Machine grinding yield (%)
This is the yield when the machine-pulverized binder is sieved with a sieve having an opening of 355 μm, and is determined by the following formula.

Yield (%) = [weight of binder passed through a 355 μm sieve (g) /
Total weight of binder on sieve (g)] × 100

(6) Loss on ignition of mat (wt%)
This is a value measured in accordance with “7.3.2 Loss on ignition” of JIS R3420 “General test method for glass fiber” and represents the ratio (% by weight) of the binder adhering to the mat based on the weight of the mat. . The specific measurement procedure is as follows.
[1] About 5 g of a test piece is placed in a magnetic crucible, dried at 105 ° C. for 30 minutes, then allowed to cool to room temperature in a desiccator, and the weight (m1) is measured to the nearest 0.1 mg. The dried magnetic crucible containing a test piece was placed in an electric furnace adjusted to a temperature of 625 ° C., burned for 5 minutes with the door open, then closed, and burned for another 10 minutes. Thereafter, the magnetic crucible containing the test piece is taken out and allowed to cool to room temperature in a desiccator, and the weight (m2) is measured to the nearest 0.1 mg.
[2] The empty magnetic crucible without a test piece is dried at 105 ° C. for 30 minutes, then allowed to cool to room temperature in a desiccator, and the weight (m0) is measured to the 0.1 mg unit.
[3] The ignition loss is calculated from the following formula.

Loss on ignition (% by weight) = 100 × [(m1) − (m2)] / [(m1) − (m0)]

(7) Mat tensile strength (N)
Ten pieces of test pieces each having a width of 50 mm and a length of 150 mm were cut out from the prepared glass chopped strand mat, and these were measured in accordance with “7.4 Tensile Strength” of JIS R3420 “Glass Fiber General Test Method” The average value of 10 test pieces was taken as the tensile strength of the glass chopped strand mat. In addition, the adhesion amount of the binder was calculated | required by the ignition loss of said (6). Specifically, the tensile strength was measured by the following procedure.
(I) The test piece is allowed to stand for 1 hour under conditions of 25 ° C. and humidity 65% (standard atmosphere defined by JIS K7100).
(Ii) Grab both ends in the length direction of the test piece with the upper and lower clamps, and adjust the distance between the clamps to 100 mm.
(Ii) Using “Autograph AGS-500D” [device name, manufactured by Shimadzu Corporation], a tensile test is performed at a tensile speed of 100 mm / min, and the force required until the test piece breaks is defined as the tensile strength. .

(8) Glass chopped strand mat flexural modulus (flexibility evaluation) (MPa)
Ten test pieces each having a width of 20 mm and a length of 100 mm were cut out from the glass chopped strand mat thus prepared, measured in accordance with ASTM D256, and the average value of the ten test pieces was determined as the bending elastic modulus of the glass chopped strand mat. It was.

<Evaluation criteria>
[1] Average value of tensile strength The average value of the tensile strength of 10 test pieces was determined and evaluated according to the following criteria.
○ Over 130N △ 70N or more and less than 130N × less than 70N

[2] Difference between maximum value and minimum value of tensile strength The difference between the maximum value and the minimum value of the tensile strength of 10 test pieces was determined and evaluated according to the following criteria.
○ Less than 40N △ 40N or more and less than 80N × 80N or more

[3] Tensile strength per ignition loss (% by weight) The average tensile strength of 10 test pieces was divided by the ignition loss (% by weight) and evaluated according to the following criteria.
○ Over 50N △ 30N or more and less than 50N × less than 30N

[4] Average flexural modulus (evaluation of flexibility)
○ Less than 1.5 × 10 ⁻³ MPa Δ 1.5 × 10 ⁻³ MPa or more and less than 2.0 × 10 ⁻³ MPa × 2.0 × 10 ⁻³ MPa or more

As is clear from Table 1, the binders of the present invention (Examples 1 and 2) have higher yields during mechanical grinding and narrow particle size distribution than the comparative binders (Comparative Examples 1 and 2). .
Further, as apparent from Table 2, it can be seen that the obtained glass chopped strand mat is excellent in tensile strength and its variation is small. Further, in comparison mats inferior in mat strength, it is necessary to increase the binder supply amount, but in the mat of the present invention, the tensile strength per ignition loss is more excellent, so the binder of the present invention is less than the conventional one. It can also be seen that the mat can be provided with the required strength uniformly by the amount used, and that the mat is excellent in flexibility.

  The binder for glass chopped strand mats of the present invention provides a glass chopped strand mat having a uniform strength and flexibility and excellent workability afterwards. The obtained mat can be used as a reinforcing material for a glass fiber reinforced plastic (FRP) molded product, and the molded product is an automobile member (molded ceiling material, etc.), a small vessel (canoe, boat, yacht, motor boat, etc.) ) Hulls, housing components (bathtubs, septic tanks, etc.), and so on.

Claims (9)

Polycondensation product of polycarboxylic acid (a1) and low molecular weight polyol (a2), self-polycondensation product of compound (a3) having a carboxyl group and a hydroxyl group in the same molecule, and ring-opening polycondensation of lactone (a4) A polyester resin (A) having a solubility parameter (hereinafter referred to as SP value) (α) selected from the group consisting of a product , polyphenylene ether resin (B1), and vinyl resin (B2). ), A polyester resin (B3), a polyamide resin (B4), a polycarbonate resin (B5), and a polyacetal resin (B6), at least one thermoplastic resin (B) having an SP value (β) Ri Na containing a powder of the molten mixture, the (alpha) is 9.5 to 13.5, a glass chopped strand map the (beta) is 8 to 16 Use binder (C).

0.2 ≦ | (α) − (β) | ≦ 3.0 (1)
2. The binder according to claim 1, wherein the volume average particle diameter Dv of (C) is 100 to 250 μm and the proportion of particles having a volume reference particle diameter of 300 μm or more is 20% by weight or less. The binder according to claim 1 or 2, wherein the weight ratio of (A) / (B) is 50/50 to 99.9 / 0.1. The binder according to any one of claims 1 to 3, wherein the proportion of particles having a volume-based particle diameter of 75 µm or less of (C) is 20 wt% or less. A glass chopped strand mat obtained by bonding a glass chopped strand laminate with the binder according to claim 1. The mat according to claim 5, wherein the difference between the maximum value and the minimum value of the tensile strength of the mat is less than 40N. A glass fiber reinforced plastic molded product obtained by molding the mat according to claim 5 or 6 as a reinforcing material. The molded article according to claim 7, wherein the glass fiber reinforced plastic molded article is for automobile molded ceiling materials, small ship hulls, bathtubs or septic tanks. The binder according to any one of claims 1 to 4, wherein a glass chopped strand mat is produced by hot press molding a glass chopped strand laminate formed through the steps of glass chopped strand dispersion, water dispersion and binder dispersion. A method for producing a glass chopped strand mat, characterized in that