JPH10265592A - Production of prepreg for printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce the subject prepreg excellent in high-frequency characteristics and heat resistance and useful in the electrical and electronic fields by dissolving a resin having compatibility with a polystyrene-based resin in a solvent, impregnating a reinforcing woven cloth with the resultant solution, drying the impregnated cloth, then melting the polystyrene-based resin and subsequently impregnating the impregnated woven cloth with the molten polystyrene-based resin, etc. SOLUTION: This prepreg is produced by dissolving a resin, having compatibility with a polystyrene-based resin consisting essentially of a syndiotactic structure and soluble in a solvent such as a srtrene-butylene-styrene copolymer, a polyphenylene ether, an epoxy resin or a modified material thereof in the solvent, impregnating a reinforcing woven cloth comprising glass fibers, organic synthetic fibers, etc., with the resultant solution, drying the impregnated woven cloth, providing an impregnated woven cloth, then melting the polystyrene-based resin and impregnating the impregnated woven cloth with the molten polystyrene-based resin or laminating a sheetlike material of the molten polystyrene-based resin onto the impregnated woven cloth.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention is useful in the electric and electronic fields, has excellent high-frequency characteristics, excellent heat resistance and high production efficiency.
The present invention relates to a method for manufacturing a prepreg for a printed wiring board.

[0002]

2. Description of the Related Art A polystyrene resin mainly having a syndiotactic structure (hereinafter abbreviated as SPS resin).
Has advantages such as low dielectric constant and dielectric loss tangent, high heat resistance, and low cost compared to other high frequency substrate resin materials. It is expected to be used as an insulating base material for laminated boards for printed wiring boards requiring excellent high-frequency characteristics such as for equipment.

[0003] In general, a method of impregnating a reinforcing woven fabric with a resin to form a so-called prepreg and then laminating the same is used for manufacturing a laminate for a printed wiring board because of its excellent productivity. When using a reinforcing woven fabric such as glass-epoxy resin and thermosetting resin as the insulating base material,
A prepreg is formed by immersing a reinforcing woven fabric in a solution of an uncured resin and an organic solvent, removing the solvent under pressure and heating, and thereby removing the solvent and semi-curing the resin.

On the other hand, SPS resin is a thermoplastic resin, has no general-purpose solvent capable of obtaining a solution suitable for impregnation, and has a high melting point of 270 ° C. Is formed into a sheet, then superimposed on a reinforcing woven fabric, and impregnated by hot pressing.

[0005]

However, in this method, the SPS resin in the molten state has a viscosity of several thousand poises, which is too high to impregnate the reinforcing woven fabric. Relatively quickly in between,
It is very difficult to enter between the fibers of the twisted yarn, it takes about 5 minutes or more under pressure, and bubbles may not remain completely between the fibers of the twisted yarn. When a printed circuit is manufactured by soldering, the soldering causes a defect such as swelling.

Accordingly, an object of the present invention is to provide a prepreg for a printed wiring board which uses an SPS resin as an insulating base material of a laminated board for a printed wiring board requiring high frequency characteristics and has high production efficiency and is free from bubbles. It is to provide a manufacturing method of.

[0007]

In order to produce a prepreg for a printed wiring board with high production efficiency using an SPS resin having excellent dielectric properties as a material, the present inventor has proposed a twisted fiber of a reinforcing woven fabric to which resin does not easily enter. In the meantime, paying attention to the fact that it is necessary to impregnate a low-viscosity resin that has been solution-ized in advance,
As a result of various studies on the method, it was confirmed that a prepreg using an SPS resin could be efficiently obtained by the following method, thereby completing the present invention.

That is, the present invention relates to a method for producing a prepreg for a printed wiring board, which comprises a reinforcing woven fabric and an SPS resin as main materials, and comprises a solvent-soluble resin compatible with the SPS resin (hereinafter referred to as a second resin). Is dissolved in a solvent, and the solution is impregnated with a reinforcing woven fabric and dried to obtain an impregnated woven fabric.
It is characterized in that the PS resin is melted and impregnated into the impregnated woven fabric or laminated with the impregnated woven fabric. that time,
The second resin is at least one selected from a styrene-ethylene-butylene-styrene copolymer, a polyphenylene ether, an epoxy resin, or a modified product thereof, and the reinforcing woven fabric is a glass fiber or an organic synthetic fiber. Preferably, at least one selected from the group consisting of:

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The SPS resin used in the present invention has a stereochemical structure in which a phenyl group or a substituted phenyl group, which is a side chain, alternates with a main chain formed from carbon-carbon bonds. In the opposite direction. Tacticity measured by nuclear magnetic resonance ( ¹³ C-NMR method) using isotope carbon is the abundance of a plurality of continuous structural units, for example, dyad for two, triad for three, and triad for five.
In the case of the SPS resin of the present invention, it is usually 75 mol% or more, preferably 85 mol% or more, or racemic pentad 30 mol% or more, preferably 50 mol% in the SPS resin of the present invention. % Of polystyrene, poly (alkyl styrene), poly (halogenated styrene), poly (halogenated alkyl styrene), poly (alkoxy styrene), poly (vinyl benzoate), and hydrogen thereof And a mixture thereof or a copolymer containing these as a main component.

Here, the poly (alkylstyrene) includes poly (methylstyrene), poly (ethylstyrene), poly (isopropylstyrene), poly (tert-butylstyrene), poly (phenylstyrene), poly (vinylnaphthalene). ), Poly (vinylstyrene), etc., and poly (halogenated styrene) as poly (chlorostyrene), poly (bromostyrene), poly (fluorostyrene), etc., as poly (halogenated alkylstyrene).
Examples thereof include poly (chloromethylstyrene), and examples of poly (alkoxystyrene) include poly (methoxystyrene) and poly (ethoxystyrene).

The comonomer component constituting the above-mentioned copolymer includes, in addition to the styrene monomer constituting the above-mentioned styrene-based polymer, olefin-based monomers such as ethylene, propylene, butene, hexene and octene, butadiene, isoprene and the like. Diene-based monomers, cyclic olefin-based monomers, cyclic diene-based monomers, and polar vinyl monomers such as methyl methacrylate, maleic anhydride, and acrylonitrile.

Of these, particularly preferred polystyrene resins include polystyrene, poly (alkylstyrene), poly (halogenated styrene), hydrogenated polystyrene and copolymers containing these structural units.

Such an SPS resin is prepared, for example, by using a titanium compound and a condensation product of water and a trialkylaluminum as a catalyst in an inert hydrocarbon solvent or in the absence of a solvent, using a styrene-based monomer (the styrene-based monomer). It can be produced by polymerizing a monomer corresponding to a polymer (JP-A-62-187708). For poly (halogenated alkylstyrene), see JP-A-1-46912,
These hydrogenated polymers can also be obtained by the method described in JP-A-1-178505.

The molecular weight of the SPS resin is not particularly limited, but the weight average molecular weight is 2,000 or more, preferably 10,000
More than 00, especially more than 50,000 are optimal. Further, the molecular weight distribution is not limited in its width, and various types can be applied.

Various additives such as a softening agent and a processing aid can be added to these SPS resins, if necessary, but these do not exceed 15 parts by weight per 100 parts by weight of the SPS resin. Is preferable because the advantage that the SPS resin has excellent dielectric properties is not impaired. Further, a thermoplastic resin compatible with the SPS resin in order to improve mechanical properties, especially impact resistance, such as a styrene polymer having an atactic structure, a styrene polymer having an isotactic structure, polyphenylene ether, and styrene -Butadiene-styrene copolymer, styrene-ethylene-butylene-styrene copolymer and the like can also be added.

Examples of the fiber material constituting the reinforcing woven fabric include glass fibers and organic synthetic fibers (for example, aromatic polyamide fibers, aramid fibers, polyimide fibers, fluororesin fibers, etc.). And glass fibers are preferred. These fibers may be used singly or in combination of two or more kinds. A filament may be put together into a twisted yarn and woven by an appropriate method such as plain weave or twill weave to obtain a reinforcing woven fabric.

The reinforcing woven fabric is preferably treated with various coupling agents in order to improve the wettability with the melt of the SPS resin and the above-mentioned second resin. Coupling agents, titanate coupling agents, and the like are exemplified. Of these, aminosilane-based coupling agents are preferred.

The degree of compatibility of the second resin is as follows:
The SPS resin and the second resin were mixed at a ratio of 1: 1 and the mixture was extruded from a co-rotating twin screw extruder having an L / D of 20 or more through a T-die having a lip of 0.5 mm, When picked up as a sheet having a thickness of mm, there is no defect caused by incompatibility of the resin, and as a solvent for dissolving the resin, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate , Butyl acetate, n-hexane, cyclohexane, cyclohexanone, naphtha and the like.

Examples of the second resin having such properties include styrene-ethylene-butylene-styrene copolymer, polyphenylene ether, epoxy resin, and modified products thereof. Although two or more kinds may be used in combination, it is particularly preferable to use polyphenylene ether as a main component because of its excellent dielectric properties and heat resistance. If necessary, various additives such as a crosslinking agent, an antioxidant, an ultraviolet absorber, and a reinforcing agent may be added to the second resin.

After the second resin is dissolved in the above solvent to form a solution, the solution is impregnated with a reinforcing woven fabric and dried to obtain an impregnated woven fabric, which is achieved by using a known impregnating apparatus. can do. In this impregnation step, the amount of impregnation of the second resin is such that it is impregnated between the fibers of the twisted yarns of the reinforcing woven fabric, for example, 10 to 10 per 1 m ² of the reinforcing woven fabric having a thickness of 0.18 mm.
It may be 0 cm ³ , and the solid content concentration in the solution can be selected from a wide range of 5 to 60%. Since the viscosity of the solution at this time has a large effect on the impregnation property, it is preferable to adjust the viscosity to 500 poise or less, particularly preferably 100 poise or less.

Next, the SPS resin is melted and impregnated into the impregnated woven fabric, or laminated with the impregnated woven fabric to form a prepreg for printed wiring. After the sheet is formed into a sheet by a method such as die extrusion, the sheet and the impregnated woven fabric are overlaid, pressurized and impregnated while heating to a temperature equal to or higher than the melting point of the SPS resin by a hot press, and then cooled, An example is a method in which a resin is extruded from a T-die and laminated with a pressure roll or the like in a molten state together with the impregnated woven fabric.

In this case, the capacity ratio between the SPS resin and the impregnated woven fabric may be determined from the relationship between the bulk density of the reinforcing woven fabric and the impregnation amount of the second resin, for example, a thickness of 0.18 mm and a basis weight. Quantity 2
Using glass fiber reinforcement woven fabric of 10 g / m ² and density 2.5,
When producing a prepreg having a thickness of 0.2 mm, the capacity ratio between the reinforcing woven fabric and the second resin + SPS resin is ideally 42:58, taking into account the allowable thickness accuracy. 45:55
It is desirable to set the range to 30:70.

In the method using a hot press, the temperature of the press is preferably heated to a temperature equal to or higher than the melting point of the SPS resin, that is, 270 ° C. or higher. And 290 ° C
It is desirable that heating be performed as described above. However, if the temperature is too high, the SPS resin is easily decomposed,
It is good to be below ° C.

The pressurizing time after the temperature reaches the melting point or more may be shorter than the conventional one, since the second resin is previously impregnated between the fibers of the twisted yarn of the impregnated woven fabric, and may be one minute. Within the final impregnation is completed. For the same reason, it is possible to apply a method of laminating with a pressure roll or the like in combination with the impregnated woven fabric in the above-mentioned molten state, and according to this method, it is possible to manufacture continuously, thereby further improving productivity.

According to the present invention, an SPS having excellent dielectric properties is provided.
By using a resin as a material, heat resistance, a prepreg for a printed wiring board having excellent dielectric properties can be obtained, and after impregnating a low-viscosity resin that has been previously solutionized between the fibers of the twisted yarn of the reinforcing woven fabric, Since the SPS resin is impregnated or laminated with the impregnated woven fabric, the production efficiency is high, and it is possible to prevent bubbles from remaining and causing swelling during soldering.

[0026]

Next, the present invention will be described in more detail with reference to examples and comparative examples. Example 1 Glass cloth # 7628 (trade name, manufactured by Asahi Schwebel Co., thickness 0.18 mm, basis weight 210 g / m ² ) treated with aminosilane-based coupling agent KBM602 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.)
Is a styrene-ethylene-butylene-styrene copolymer Tuftec M1913 (trade name, density 0.92, manufactured by Asahi Kasei Corporation)
g / cm ³ ) of xylene: methyl isobutyl ketone = 9: 1
After being immersed in a 20% solution of the mixed solvent, the mixture was drained through a pinch roll and dried through a hot air drying oven at 180 ° C. to obtain an impregnated woven fabric having a resin amount of 30 g / m ² . On the other hand, SPS resin composition
XAREC S-100 (trade name, manufactured by Idemitsu Petrochemical Co., Ltd.) was formed into a sheet having a thickness of 0.07 mm and a basis weight of 70 g / m ² by T-die extrusion molding. The two sheets sandwiched one of the impregnated woven fabrics. 300 ℃, 5
After pressing for 1 minute under the conditions of ^{0kgf / cm 2, 150 ℃,} 50kgf
Crystallization at 1 / cm ² for 1 minute, thickness 0.2mm, basis weight 3
A prepreg for printed wiring boards of 24 g / m ² was obtained. The measured porosity was 0%.

Comparative Example 1 The SPS resin composition XAREC S-100 (described above) was previously formed into a 0.09 mm-thick sheet by T-die extrusion.
300 pieces of glass cloth # 7628 (shown above) treated with aminosilane coupling agent KBM602 (shown above)
After pressing for 1 minute at 50 ° C / 50kgf / cm ² ,
Crystallization was performed at 0 kgf / cm ² for 1 minute to obtain a prepreg for a printed wiring board. When this porosity was measured, 23
%Met. In a test in which the press time was extended, it took 12 minutes to reduce the porosity of the prepreg for a printed wiring board to 0%.

Example 2 Aminosilane coupling agent KBM60 as a reinforcing woven fabric
2 Use glass cloth # 7628 (described above) treated in (described above) and use it as a polyphenylene ether resin Zylon 500Z.
After dipping in a 20% solution of xylene: methylisobutylketone = 9: 1 mixed solvent (trade name, manufactured by Asahi Kasei Kogyo Co., Ltd., density: 1.08 g / cm ³ ), the solution was removed through a pinch roll, and then 180 ° C.
, And the process was repeated once again to obtain an impregnated woven fabric having a resin amount of 50 g / m ² . On the other hand, two extruders equipped with a T die are installed facing each other,
While extruding the PS resin composition XAREC S-100 (described above) at a thickness of 0.037 mm, the impregnated woven fabric is passed between the extruded molten sheets while heating, and is laminated using a pinch roll. A prepreg for a printed wiring board of the present invention having a thickness of 0.2 mm and a basis weight of 330 g / m ² was obtained. The measured porosity was 0%.

[0029]

According to the present invention, since a printed wiring board is manufactured by using SPS resin as a resin material, heat resistance and dielectric properties are excellent, and high-speed arithmetic processing which requires excellent high-frequency properties is required. , Satellite broadcasting reception, small communication equipment, etc., advantages such as little heat generation and little noise are obtained. In addition, since a prepreg for a printed wiring board having a small gap can be efficiently obtained, the manufacturing cost can be reduced, and a printed wiring board which does not swell due to heating such as plating solution soaking or soldering caused by the gap can be obtained.

Claims (3)

[Claims] 1. A method for producing a prepreg for a printed wiring board, comprising a reinforcing woven fabric and a polystyrene-based resin mainly having a syndiotactic structure as a main material, wherein the solvent-soluble prepreg is compatible with the polystyrene-based resin. After dissolving the resin in a solvent, impregnating the solution with a reinforcing woven fabric and drying to obtain an impregnated woven fabric, the polystyrene resin is melted and impregnated into the impregnated woven fabric, or laminated with the impregnated woven fabric. A method for producing a prepreg for a printed wiring board. 2. The solvent-soluble resin compatible with the polystyrene resin is at least one selected from styrene-ethylene-butylene-styrene copolymer, polyphenylene ether, epoxy resin, and modified products thereof. A method for producing a prepreg for a printed wiring board according to claim 1. 3. The method for producing a prepreg for a printed wiring board according to claim 1, wherein the reinforcing woven fabric is made of at least one selected from glass fibers and organic synthetic fibers.