JPH0223626B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for preventing fraying of glass fabric impregnated with resin varnish and used as a printed circuit board. In the past, glass fabrics were often woven using shuttle looms, but in recent years, fragment looms called innovative looms have been developed and are rapidly becoming popular due to their efficiency and good quality. Glass fabrics woven using fragmentary weaving machines are different from fabrics produced using shuttle looms, in which the weft yarns are folded back at the ends of the fabric to form adjacent weft yarns, but each weft yarn is inserted independently at a constant length, and then the fabric is wefted. The edges are cut slightly longer than the width of the fabric, creating a so-called "tassel selvage"
is formed. When a glass fabric having such tassels is used for impregnating resin varnish, the tassels impregnate a large amount of varnish. Furthermore, since this portion must be cut, it is not desirable from both a cost and process standpoint. Another drawback of the tassel selvedge is that, since the weft yarns are not folded back, the warp yarns easily fray during the varnish impregnation process, which can cause problems such as winding around the roll. It has been difficult to solve this problem at the same time because the shorter the length of the tufted ears is, the more likely this fraying will occur in order to reduce the resin loss at the tufted ears. On the other hand, not only textiles woven on fragmentary looms but also textiles woven on shuttle looms are often divided into two or three parts. When making severe cuts, the warp threads easily become frayed. In order to prevent the above-mentioned fraying, it has been considered to cut the tassel edges or the base of the fabric using a laser beam while melting and adhering the glass threads. However, the adhesive strength of laser melting is weak, and the adhesive part easily peels off when subjected to strong ironing, and the molten glass forms minute spherical objects that fall into the varnish bath during the resin varnish impregnation process. It has drawbacks and is not a perfect countermeasure. On the other hand, attempts have been made to prevent fraying by applying hot melt adhesive to the tuft selvage, the cut shortened tassel selvage, or the cut portion. However, resin varnishes include acetone, methyl ethyl ketone,
A wide variety of organic solvents are used, such as methyl cellosolve, methanol, ethanol, dimethylformamide, toluene, and hexane, and if adhesives are eluted from these solvents during the varnish bath or after varnish impregnation, the performance of the varnish may be affected. There is. In particular, for varnish-impregnated glass fabrics used in fields that require a high level of quality assurance, such as printed circuit boards, it is essential that the adhesive does not elute.
Vinyl acetate copolymers or copolymers whose main component is polyamide obtained by reacting polymerized fatty acids and aliphatic amines do not have sufficient solvent resistance and cannot be used. Furthermore, attempts have been made to use thermosetting resins such as epoxy resins and phenolic resins as adhesives. Although these thermosetting resins have relatively good chemical resistance, they require a considerable amount of time to harden after being applied to glass cloth, and are not necessarily satisfactory in terms of equipment and productivity. Furthermore, nylon 6, nylon 66, polyethylene terephthalate, polybutylene terephthalate,
Attempts have been made to melt and heat thermoplastic resins such as polyphenylene ether and extrude a small amount, or to form a film and adhere it, but these resins have relatively high melting points and high heats of fusion. However, it is difficult to apply and impregnate trace amounts of resin onto glass fabrics at a significant degree. According to the research conducted by the present inventors, this method is possible only when the melting point of the thermoplastic resin is 200℃ or lower and at 220℃ or lower.
It is necessary that the melt viscosity at °C is 500,000 centipoise or less. In this case, if the impregnation is insufficient, fuzz of the glass thread may occur from the cut part, and the thickness of the fabric in the coated area will be significantly thicker than in other areas, so the glass fabric may be wound into a roll. This causes problems such as so-called "ear height" when taking the head. If it reaches the height of the ears, it will not be possible to wind it to the desired length. If the glass fabric is rolled with strong tension, the glass fabric is likely to break at the edges, and if it is rolled too loosely, the weave will collapse and the product will not have good shape stability. After all, if a large amount of anti-fray agent is applied, the effect of preventing fraying is large, but as mentioned above, it is a big problem when winding into a roll form. On the other hand, if the amount of anti-raveling agent applied is small, there will be a contradiction in that although there will be no problem with rolling, a sufficient anti-fraying effect will not be obtained. Furthermore, conventionally used adhesives such as ethylene-vinyl acetate copolymer have a drawback of long open time when applied in the form of an organic solvent solution. In other words, ethylene-
When a solution of a commonly used adhesive such as vinyl acetate copolymer is applied, the solution does not solidify easily and when wound into a roll form, the adhesive retains its tack for a long time, causing the adjoining glass fiber fabric to bind. There is a problem with the layers adhering to each other. As a result of intensive research into a method for preventing fraying of glass fabrics that completely overcomes the above-mentioned drawbacks, the present inventors have found that it is extremely effective to apply a certain type of copolymerized polyester resin in the form of an organic solvent solution as a method for preventing fraying. They have found that this is effective and have completed the present invention. That is, in the method for preventing fraying of glass fabric according to the present invention, 40 to 90 mol% of the carboxylic acid component is terephthalic acid, and 10 to 60 mol% is isophthalic acid and a saturated aliphatic dicarboxylic acid having 4 to 20 carbon atoms. A copolymerized polyester resin composed of at least one dicarboxylic acid component selected from among and at least one glycol component selected from alkylene glycols having 2 to 10 carbon atoms, A chlorinated hydrocarbon solution of resin at a temperature of 100°C or higher is applied to the tassel selvage of a glass fabric woven on a piece loom in such a proportion that the fabric thickness after application of the resin is substantially the same as the fabric thickness before application of the resin. It is characterized by impregnating a portion or cut portion of a cut glass fabric and then volatilizing the solvent, or impregnating the glass fabric and volatilizing the solvent before cutting. Glass fabrics whose fraying has been prevented by the method of the present invention are particularly useful for impregnation with varnish. In the copolyester resin used in the present invention, dicarboxylic acid components constituting the resin include terephthalic acid, isophthalic acid, and carbon atoms of 4 to 4.
20 aliphatic dicarboxylic acids, such as succinic acid, glutaric acid and sebacic acid, can be used, and as the glycol component, alkylene glycols having 2 to 10 carbon atoms, such as ethylene glycol, 1,2-propanediol, 1 , 3-propanediol, 1,4-butanediol, 1,6-
Although hexanediol and the like can be used, the present invention is not limited to these examples. These glycol components may be used alone or in combination of two or more. In addition, the proportion of terephthalic acid in the total carboxylic acid component is important from the viewpoint of solvent resistance, and if the terephthalic acid content is less than 40 mol%, it will dissolve easily in acetone, methyl ethyl ketone, dimethyl formamide, etc., so varnish impregnation. Elution during the process becomes a problem. If the proportion of terephthalic acid in all carboxylic acids exceeds 90 mol%, the solubility in low-boiling organic solvents such as methylene chloride will be poor. In order to impregnate the glass fabric with the copolymerized polyester resin, for example, a method can be adopted in which the copolyester resin is dissolved in an organic solvent such as methylene chloride and the resulting solution is applied. The resin has excellent solvent resistance and is characterized by not eluting during the resin varnish impregnation process.
It is slightly soluble in chlorinated hydrocarbons such as methylene chloride and trichlene. However, in the process of impregnating glass fabric with resin varnish, almost no elution is observed, and in the field where glass fabric is used as a base material for resin varnish impregnation, epoxy resin, unsaturated polyester resin, polyimide resin, silicon Although resins are well known, chlorinated hydrocarbon solvents such as methylene chloride and trichlene are rarely used for these.
These solvents fully meet the purpose of the present invention because they have a low boiling point, are easily volatilized, and are not flammable. After applying and impregnating the solution,
The solvent should be stripped off by a suitable method such as exposure to hot air. After volatilizing the solvent, it is effective to expose the resin to hot air or pressurize it using a heated roll or the like in order to further sufficiently impregnate the resin and improve the fraying effect. In this case, care must be taken to avoid deteriorating the silane coupling agent, etc., which is usually applied to the surface of the glass cloth due to heating, and for this reason, a low boiling point solvent is preferable. It is desirable that the organic solvent for the copolymerized polyester resin be applied along the warp direction to the selvage portion or ground portion of the glass fabric woven using the fragmented fabric. Also,
The amount to be applied is determined so as not to cause problems such as so-called "edge height" when winding the glass fabric into a roll.
The fabric thickness after resin application is made to be substantially the same as the fabric thickness before application. Thus, by applying the fray prevention method of the present invention, it is possible to extremely advantageously obtain a glass fabric impregnated with varnish, which is used as a printed circuit board, which particularly requires a high level of quality. Hereinafter, the present invention will be described in detail with reference to the following examples, but the present invention is not limited to the following examples unless it departs from the gist thereof. Example 1 A dicarboxylic acid component consisting of 65% mol% terephthalic acid, 10 mol% isophthalic acid, and 25% adipic acid, and a glycol component consisting of 1,4-butanediol, with a softening point of 173°C and at 200°C. A copolymerized polyester resin having a melt viscosity of 400 poise measured using an elevated flow tester was obtained by performing transesterification, esterification, and polycondensation using a tetraisopropyl titanate catalyst. Table 1 shows the solvent resistance of this resin.

【table】

[Table] The above copolymerized polyester resin was dissolved in methylene chloride in an amount of 4% by weight. The solution viscosity was 100 centipoise. This was applied linearly to the center of a 0.2 mm glass fabric woven using a shuttle loom at a rate of 1.5 cc per meter, and then dried for 1 minute in an atmosphere at 200° C. using a hot air dryer. The spread of the coated area was 7 mm. The center of this coated area was tested for fraying at the cut portion with scissors, but no fraying occurred at all. In addition, the thickness of the fabric in the coated area was 0.2 mm, which was exactly the same as before coating, and even when the glass fabric that had been prevented from fraying in this example was wound into a roll, no difference was observed between the coated area and the non-coated area. . Comparative Example 1 A dicarboxylic acid component consisting of 30 mol% of terephthalic acid, 50 mol% of isophthalic acid, and 20 mol% of adipic acid, and a glycol component consisting of 1,4-butanediol, with a softening point of 78°C and 200°C. Example 1 A copolymerized polyester resin having a melt viscosity of 450 poise measured using an elevated flow tester was
obtained in the same way. This copolyester resin completely dissolved in methyl ethyl ketone and dimethyl formaldehyde in a 72 hour immersion test at 20°C. Example 2 Types of dicarboxylic acid component and glycol component,
Polyesters were produced basically in the same manner as in Example 1 with various compositions. (Note that manganese dioxide was used as the transesterification catalyst only when ethylene glycol was used as the glycol component, but the same trimethyl phosphate as in Example 1 was used in other cases.) The composition and properties of these polyesters are shown in Table 2. show. Furthermore, these polyesters were applied to glass cloth in the same manner as in Example 1 to obtain a glass cloth having ears with strong sealing power. Comparative Example 2 A dicarboxylic acid component consisting of 38 mol% of terephthalic acid, 32 mol% of isophthalic acid, and 30 mol% of adipic acid, and a glycol component consisting of 100 mol% of 1,4-butanediol, with a softening point of 95°C.
Melt viscosity by elevated flow tester at 200℃
Example 1 Polyester resin with 440 poise
obtained in the same way. This resin was also completely dissolved in toluene, dimethylformamide, etc. Table 3 shows its properties. Comparative Example 3 A polybutylene terephthalate homopolymer consisting of a dicarboxylic acid component consisting of 100 moles of terephthalic acid and a glycol component consisting of 100 moles % of 1,4-butanediol was obtained in the same manner as in Example 1. The softening point of this resin was 230°C. This resin was poorly soluble in methylene chloride and other organic solvents by the method of Example 1.

【table】

【table】

【table】

【table】

Claims (1)

[Claims] 1 Dicarboxylic acid component in which 40 to 90 mol% is terephthalic acid and 10 to 60 mol% is at least one selected from isophthalic acid and saturated aliphatic dicarboxylic acids having 4 to 20 carbon atoms. A copolyester resin composed of an acid component and at least one glycol component selected from alkylene glycols having 2 to 10 carbon atoms, with a softening point of 100°C.
A chlorinated hydrocarbon solution of the above resin was applied to the tufted edges or cuttings of a glass fabric woven on a fragmentary loom in such a proportion that the fabric thickness after the resin was applied was substantially the same as the fabric thickness before the resin was applied. impregnate the cut part of the glass fabric and then evaporate the solvent, or
Alternatively, a method for preventing fraying of a glass fabric for a printed circuit board, which comprises impregnating the glass fabric, evaporating a solvent, and then cutting the fabric.