JP2599388B2 - Aqueous dispersion - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a glass fiber cloth, and more particularly to an aqueous dispersion for fixing a tab end of a glass fiber cloth for providing a prepreg of a band-shaped glass fiber cloth.

[Prior art and its problems] A prepreg is a laminated molding material obtained by impregnating a thermosetting resin into a continuous reinforcing material such as woven fabric, paper, mat, etc., and then drying and semi-curing the thermosetting resin. is there. Generally, a thermosetting resin is dissolved and impregnated into a glass fiber cloth or the like as a varnish.

Conventionally, when providing an inorganic fiber fabric to the prepreg,
From the viewpoint of cost and quality of the fabric, fabrics woven with a shuttleless loom such as an air jet are often used.

[Problems to be solved by the invention]

The following problems occur when a glass fiber cloth band having a tufted ear woven by the shuttleless loom is used for prepreg.

The first problem is that the glass fiber cloth band contains excess resin in the portion of the stuffing ears, and the thickness of the ears is thicker than other parts. Therefore, if the stack is cut to the required length, the location of the ears becomes high, causing a load collapse.When obtaining a copper-clad laminate using a prepreg, uniform pressing of the entire prepreg width is possible. There are no drawbacks.

The second problem is that when looking at the shape of both ends of the width of the prepreg in the longitudinal direction, it is not linear but irregular due to the tufted ears. However, when the edges are difficult to align, and when the edges are further aligned, a part of the unevenness is scattered and cut into the prepreg, which causes a defective product.

A third problem is that the glass fibers in the portion of the tabs are cut off during the production of the prepreg, mixed into the varnish, and adhere to the surface of the prepreg, causing a defective product.

In order to solve the above problem, a method of cutting the ear portion after prepreg production is also conceivable. However, the third problem cannot be solved, and the yield of the glass fiber cloth and the varnish decreases, which is not preferable in terms of cost. .

Japanese Patent Application Laid-Open No. 52-34094 discloses that when a wide glass fiber cloth band is cut in the longitudinal direction to form a narrow glass fiber cloth band, an acrylic, polyvinyl acetate, rubber It has been proposed that an adhesive of a polyvinyl chloride type or the like, particularly preferably a polyvinyl acetate adhesive compatible with a polyester resin be applied as a fraying-preventing agent, but the adhesive used in this method has been proposed. Is the solvent of the thermoset resin varnish impregnation and the temperature of the varnish curing is questionable. Also, in Japanese Patent Application Laid-Open No. 48-18568, for knitted fabrics and woven fabrics in general, when cutting along stitches or weaves, it is possible to impregnate the cut portion with a heat-fusible synthetic resin to prevent the fraying phenomenon. Although proposed, this method does not provide a good prepreg having an uneven thickness of the impregnated portion. Japanese Patent Application Laid-Open No. 60-15111 discloses a method of removing the residual strain of glass fiber by heat-treating the inner part of the ear of a glass fiber cloth, and then insulating a thermosetting resin varnish insoluble and having a softening point of 150 ° C to 180 ° C. It proposes applying a solution and drying the solvent. In this method, the saturated polyester resin solution is applied to the ears of the glass fiber cloth, so that the obtained glass fiber cloth strip has the ears fixed uniformly, and the above-mentioned problems in prepreg production are almost solved. On the other hand, various problems remain in the steps of applying and drying the saturated polyester resin solution. That is, the solvent used in the saturated polyester resin solution proposed by this method is a solvent capable of lowering the drying temperature of a low boiling point, and such a solvent is a halogenated lower hydrocarbon-based solvent, for example, Methylene chloride, chloroform and the like. As is well known, these solvents are unfavorable in the working environment, and the main problem lies in environmental measures. Therefore, it is necessary to use a closed system throughout the entire process from the preparation of the polyester resin solution to the coating and drying processes, and there remains a problem to be solved in production such as a large capital investment and an extremely high production cost of the glass fiber cloth. doing.

The present invention solves the problems of the prior art as described above, and provides an aqueous dispersion for fixing the tassel ears which is useful for producing environmentally-hygienic and preferably high-quality prepreg. Aim.

[Means for solving the problem]

The present inventors have conducted intensive studies to solve the above problems, especially the application of the saturated polyester resin solution to the ears of the glass fiber cloth, and the problem of drying. As a result, the aqueous dispersion of the saturated polyester resin is effective. And completed the present invention.

That is, the object of the present invention is to provide (a) 60 to 95 mol% of terephthalic acid and (b) 5 to 20 mol
Mol%, dicarboxylic acids other than (c), (a) and (b) 0
35 mol% of dicarboxylic acid component and 2 carbon atoms
~ 10 alkylene glycols, melting point 160-220
The main component is a copolymerized polyester having a reduced viscosity of 0.2 to 0.7 dl / g and an average particle diameter of 1 μm.
This is achieved by an aqueous dispersion for fixing glass fiber cloth, which is characterized by the following.

The aqueous dispersion of the present invention has a polyester average particle diameter of 1 μm.
Due to the following fine particles, the glass fiber cloth structure is uniformly impregnated in the impregnation of the glass fiber cloth. Further, when the water is evaporated and dried, and the polyester is heated to a temperature higher than the melting point of the polyester at the same time, the polyester is melted. Further, since the adhesiveness to glass is good, the glass fibers are strongly fixed. Further, since it is an aqueous dispersion, the contamination of the working environment in the preparation of the aqueous dispersion, application to the glass fiber cloth, evaporation of water, and drying steps is completely eliminated. Furthermore, the obtained glass fiber cloth has no fraying of the ears and is uniform in thickness, and the polyester of the present invention has excellent resistance to the varnish used in the production of prepreg, and furthermore has excellent heat resistance temperature during varnish curing. Therefore, a good prepreg can be obtained.

In the polyester used in the present invention, the proportion of terephthalic acid in all dicarboxylic acid components is selected in the range of 60 to 95 mol%. When the terephthalic acid component is less than 60 mol%, the obtained polyester has poor resistance to the thermosetting resin varnish, and generally has a low melting point, which causes problems such as re-melting of the applied polyester during varnish curing. . If it exceeds 95 mol%, the dispersibility of the polyester resin in water becomes poor.

In the present invention, the sulfonic acid metal base-containing dicarboxylic acid is extremely important in that it determines the dispersibility of the obtained polyester in water and the fixation to glass fibers. Sulfonate metal base-containing dicarboxylic acids include sulfoterephthalic acid, 5-sulfoisophthalic acid, 4-sulfoterephthalic acid, 4-sulfonaphthalene-2,7-dicarboxylic acid,
Metal salts of 5 [4-sulfophenoxy] isophthalic acid can be mentioned. As metal salts, Li, Na, K, Mg, Ca, Cu, F
and salts such as e. Particularly preferred is 5-
Sodium sulfoisophthalic acid. The dicarboxylic acid containing the sulfonic acid metal base is 5 parts based on the total dicarboxylic acid component.
In the range of ~ 20 mol%. If the amount is less than 5 mol%, the dispersibility of the polyester resin in water becomes extremely poor, and a dispersion having an average particle diameter of 1 μm or less cannot be obtained. On the other hand, when the content exceeds 20 mol%, the dispersibility of the obtained polyester resin in water and the fixability to the glass fiber cloth are good, but the melting point of the obtained polyester resin is low, and the heat resistance of the thermosetting resin varnish is reduced. Resistance decreases.

In the present invention, dicarboxylic acids other than terephthalic acid and sulfonic acid metal base-containing dicarboxylic acids can be used in an amount of 0 to 35 mol% based on all dicarboxylic acids.
For example, isophthalic acid, orthophthalic acid, succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, dimer acid, tetrahydrophthalic acid, hexahydrophthalic acid, and the like can be used. If these dicarboxylic acids exceed 35 mol% based on the total dicarboxylic acids, the melting point of the obtained polyester resin decreases, resulting in poor heat resistance at the time of varnish impregnation.

The glycol component used in the polyester resin of the present invention is mainly composed of an alkylene glycol having 2 to 10 carbon atoms, such as ethylene glycol, 1,3-propanediol, 1,4-butanediol, and 1,5-pentadiol. ,
Examples thereof include 1,6-hexanediol, neopentyl glycol, diethylene glycol, and triethylene glycol. These alkylene glycols may be used alone or as a mixture of two or more. Particularly preferred alkylene glycols are ethylene glycol and a combination of the glycol and diethylene glycol.

The melting point of the polyester resin of the present invention is 160 to 210.
It is preferable that the reduced viscosity is in the range of 0.2 to 0.7 dl / g. When the melting point is less than 160 ° C., the polyester resin fixed to the glass fiber cloth is softened or re-melted during the thermosetting of the thermosetting resin varnish during the production of the prepreg, so that the prepreg is contaminated. On the other hand, if the melting point of the polyester resin is too high, the temperature for melting the polyester resin in the aqueous dispersion liquid impregnated in the glass fiber cloth and fixing it to the glass fiber becomes high, which is disadvantageous in energy cost. Generally 22
0 ° C. or lower is preferred. In addition, when the reduced viscosity of the polyester resin is less than 0.2 dl / g, the condensation power of the polyester resin itself is weak, and the glass fiber cloth band is damaged by bending, and is not reduced to 0.
If it exceeds 7 dl / g, the molecular weight of the polyester resin becomes too high, and the dispersibility in water becomes poor.

The polymerization method of the polyester of the present invention is not particularly limited, and it can be carried out according to a usual method.
For example, there is a method in which a predetermined amount of a sodium salt of terephthalic acid or 5-sulfoisophthalic acid or an ester-forming derivative thereof is directly esterified or transesterified with the above-mentioned glycol, followed by polycondensation. that time,
Any of various commonly used catalysts, stabilizers, modifiers and additives may be used.

The aqueous dispersion of the polyester resin obtained in the present invention can be prepared by a usual method. For example, the above-mentioned polyester resin is put into warm water of 80 to 100 ° C., and can be made water-soluble by slowly stirring, and then the aqueous solution is gradually cooled to room temperature to obtain a uniform acid solution. This dispersion is not strictly strict in physicochemical terms, but also includes those that are partially dissolved in water and partially finely dispersed.

The concentration of the polyester resin in the aqueous dispersion of the present invention is 5 to 5.
30% by weight is preferred. If the amount is less than 5% by weight, the amount of the polyester resin impregnated in the structure of the glass fiber cloth is insufficient, and the fixing of the glass fiber becomes insufficient. If the amount exceeds 30% by weight, the fixing portion becomes thicker than other portions.

Further, the dispersion liquid that can be used in the present invention must have an average particle size of the polyester resin of 1 μm or less. If the average particle size exceeds 1 μm, the impregnation of the glass fiber cloth into the tissue becomes uneven, and a glass fiber cloth having a uniform thickness cannot be obtained.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.

In addition, the obtained polyester resin and aqueous dispersion liquid were tested by the following evaluation methods.

◎ Melting point: Differential calorimeter (PerkinElmer Model 75)
0) was measured.

還 元 Reduced viscosity: 1 g of the polymer was dissolved in 1 dl of O-chlorophenol and measured at 35 ° C.

◎ Water dispersibility: 10 g of a polyester resin was charged into 100 cc of hot water at 95 ° C., and was stirred and dissolved for 60 minutes in a water-solubilizing tank provided with a stirring device and a reflux device. Subsequently, the temperature is gradually cooled to room temperature, and the light scattering method (a scattered light single-type photometer model 6000 manufactured by CN Ut, USA)
The average particle size was measured.

◎ Varnish resistance: Glass fiber cloth fixed with polyester resin is coated with epoxy resin varnish (AER- manufactured by Asahi Kasei Corporation).
711 EK80 125 parts, dimethylformamide 20 parts, methyl cellosolve 20 parts, methyl ethyl ketone 10 parts, acetone 5
Parts, dicyandiamide 3.0 parts, benzyldimethylamine
The varnish was treated with a varnish consisting of 0.2 parts (hereinafter abbreviated as varnish A) to test the varnish resistance.

That is, as a room temperature test, a glass fiber cloth is used at room temperature (25 ° C).
Then, the resin was immersed in varnish A for 10 minutes, and the resistance of the polyester resin to the varnish was determined from the appearance. As a thermosetting test, a glass fiber cloth was impregnated with varnish A and then heated to 200 ° C.
The varnish was thermally cured in an oven for 2 minutes, and the appearance change of the polyester resin after the thermal curing was determined.

Example 1 262.2 parts by weight (1.35 mol) of dimethyl terephthalate, 5
-Sodium sulfoisophthalic acid dimethyl ester 44.4
Parts by weight (0.15 mol), 209.6 parts by weight of ethylene glycol, (3.38 mol) and 0.15
The transesterification reaction was carried out under a nitrogen stream at 140 to 220 ° C. while distilling off methanol. Next, 0.09 parts by weight of trimethyl phosphate and 0.13 parts by weight of antimony trioxide were added, and the temperature was raised from 220 ° C. to 260 ° C. over 1 hour. In parallel with this, polycondensation was performed for 2 hours under the condition of 1 mmHg while gradually reducing the pressure. Then, a polyester (A) was obtained. This polymer had a melting point of 212 ° C. and a reduced viscosity of 0.4 dl / g.
As a result of testing the dispersibility of the polyester (A) in water,
10 g of the polyester (A) was completely dissolved in 100 cc of hot water at 95 ° C., and the average particle size of the polymer at room temperature was 0.1 μm. Next, the above-mentioned aqueous dispersion was applied in a width of 10 mm to the inner portions of the ears on both sides of a band-shaped glass fiber cloth (manufactured by Asahi Schwebel, Inc., 9628) woven by an air jet loom. The mixture was heated for 1 minute to evaporate water and melt the polyester A, followed by cooling at room temperature. The ears of the obtained glass fiber cloth were uniformly fixed with polyester A, and the thickness of the ears was not different from the part not treated with polyester A.

The ear treated with the aqueous dispersion of polyester A was cut and sampled, and the varnish A resistance was tested. As a result, it was found that there was no change in the appearance and the varnish had very good resistance.

Example 2 and Comparative Example Several kinds of polyesters were polymerized in the same manner as in Example 1 except that the dicarboxylic acid component and the glycol component were changed. Table 1 shows the composition and physical properties of these polyesters.

The symbols used in Table 1 indicate the following.

TPA; terephthalic acid SIPM; 5-sodium sulfoisophthalic acid dimethyl ester IPA; isophthalic acid ADA; adipic acid EG; ethylene glycol 1,4-BD; 1,4-butanediol DEG; diethylene glycol Since the dispersion is constituted as described above, as is clear from the examples, the aqueous dispersion of the present invention is excellent in fixing to the ear of a glass fiber cloth band, and is also a thermosetting resin for prepreg. Because of its excellent varnish properties, the glass fiber cloth treated with the aqueous dispersion can be effectively used for prepreg applications.

Furthermore, since the dispersion of the present invention is aqueous, there is no contamination of the working environment during the entire process from preparation of the dispersion, application to the glass fiber cloth, and drying, and is effective for fixing the ear of the glass fiber cloth band. Available to

Continuation of the front page (72) Inventor Norio Tsujioka 515 Kojimacho, Moriyama-shi Asahi Schwebel Co., Ltd. (56) References JP-A-60-194182 (JP, A) JP-A-56-88454 (JP, A) Kaisho 61-85437 (JP, A)

Claims (1)

(57) [Claims] (1) (a) 60 to 95 mol% of terephthalic acid, (b)
5-20 mol% of a dicarboxylic acid containing a sulfonic acid metal base,
(C), 0-35 mol% of dicarboxylic acids other than (b) and (b)
A dicarboxylic acid component comprising an alkylene glycol having 2 to 10 carbon atoms, having a melting point of 160 to 220 ° C. and a reduced viscosity of 0.2 to 0.7 dl / g as a main component, and an average particle diameter of the polyester. Is 1 μm or less, the aqueous dispersion for fixing glass fiber cloth.