JPS606231B2 - Plate base material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a plate-like base material suitable for use in, for example, laminates, particularly laminates for printed circuits, which has excellent strength and dimensional stability, and is also excellent in machinability such as room-temperature punching and cutting. Regarding.

Glass woven fabric is known as a base material for electrical insulation for electronic equipment, measuring equipment, and telecommunications equipment, or for steel-clad laminates for printed circuits, which generally require high quality.

The laminate made of this base material has excellent mechanical strength, normal and thermal dimensional stability, etc., but has the disadvantage that machinability such as cold punching and cutting is extremely poor and it is expensive. . Therefore, recently, glass fiber nonwoven fabrics, which have very good room-temperature punching properties and other machinability, and can be used to manufacture laminates at a much lower cost than glass woven fabrics, have been used as an alternative to glass woven fabrics. It has been used as a However, since glass fiber nonwoven fabric has longitudinal glass fibers bonded together in a dispersed state and has a lower apparent density than glass woven fabric, laminates using this as a base material have poor mechanical strength, normal In terms of thermal dimensional stability, it is considerably inferior to those based on glass woven fabric. General glass fiber non-woven fabric is produced by dispersing chopped glass fiber strands with a fiber diameter of 9 mm and a fiber length of 6 to 13 in water to loosen them into single fibers, which are then made into a homogeneous sheet using a paper machine. It is manufactured by applying adhesive to bond fibers together.

The glass fiber nonwoven fabric manufactured in this way has a weight of, for example, 50 ta', and the apparent density at the thickness of 0.25 is as low as 0.20 mm/mm, which is about the same as that of the glass woven fabric. It is 1/5. Furthermore, since this is made up of dispersed glass single fibers bonded together, it has the disadvantage that mechanical strength such as bending strength and tearing strength is low when processed into a laminate. In addition, as mentioned above, the apparent density is about 1/5 of that of glass woven fabric, and the fact that it is bulky means that when it is made into a laminate,
Inevitably, the resin ratio is high, which tends to cause uneven pressing and thickness fluctuations during press processing.Also, the glass fiber that is the aggregate is dispersed in a single fiber lengthwise fibrillated state, so it lacks rigidity and is weak. As a result, the resulting laminates tend to warp or twist, and have the drawback of lacking normal dimensional stability. Furthermore,
A high resin ratio means a high tensile shrinkage rate during heat exposure, and a lack of thermal dimensional stability. When used as a substrate for insulation or printed circuit boards, it has the drawback of poor reliability. The present invention has been made in view of the above points, and has mechanical strength such as bending strength and tear strength comparable to that of glass woven fabric, as well as normal and thermal dimensional stability. The object of the present invention is to provide a plate-like substrate which has excellent machinability such as room-temperature punching and cutting, and which can be manufactured into a laminate at a lower cost than glass woven fabric.

That is, in the present invention, a loosened single glass fiber sheet is mixed with a glass fiber sheet in which a plurality of glass fibers are held in a concentrated state, and each constituent fiber of this mixed sheet is bonded with an adhesive. By using a non-woven fibrous sheet consisting of a non-woven fibrous sheet to bring out the reinforcing effect of the rigidity of glass fibers, mechanical strength such as bending strength and tearing strength is significantly improved. By doing so, the apparent density is increased in exchange for the mixing of the glass fibers, so that the resin ratio does not increase when it is made into a laminate,
The present invention relates to a plate-shaped base material that improves defects in normal and thermal dimensional stability caused by a high resin content, and has good machinability and economical efficiency in cold punching, cutting, etc. .

Next, the plate-shaped substrate of the present invention will be explained in more detail.

First, a glass fiber bundle having a length of about 5 ribs and a bundle number of 100 to 1,600 fibers is mixed with glass fibers that have been woven into single fibers in a concentrated state to make paper.

In this case, in order for the rigidity of the glass fiber east to exhibit a reinforcing effect, the glass fiber east must be at least 3 skin t%, preferably 50 to
It is necessary to include 7% of enemies. If it is less than 3 t%, the physical properties of the glass fiber nonwoven fabric mentioned above will not be significantly improved, and if it is more than 7 t%, poor machinability similar to that seen in glass woven fabrics will occur.

As a sizing agent, for glass fibers that are loosened into single fibers, a sizing agent containing an aqueous solution of starch or polyvinyl alcohol, or a dispersion stabilizer is used to loosen the glass fibers easily and keep them in good condition. It is preferable to use a vinyl acetate-based material, for example, to keep the glass fiber east in a state where it is difficult to unravel. In addition, by applying a coupling agent to these single glass sheets and glass fibers, it is possible to improve the adhesion between the resin and the base material when impregnating them with resin. Next, an adhesive is applied to the mixed sheet of glass single fibers and glass fiber bundles produced as described above to form a glass fiber nonwoven fabric. In this case, various adhesives such as vinyl acetate, acrylic, epoxy, and polyvinyl alcohol are used depending on the purpose, but when used for laminates, epoxy adhesive is used. Agents are preferred. An inorganic filler is fixed to the glass fiber nonwoven fabric formed as described above.

The mineral filler is preferably dispersed in water in the presence of a protective colloid and fixed to the glass fiber nonwoven fabric. As the protective colloid agent, casein, polyvinyl alcohol, acrylic acid ester, styrene, maleic acid ester, etc. are preferable. As the inorganic filler, silica, calcium carbonate, aluminum hydroxide, mica powder, talc, asbestos, glass powder, diatom, etc. are used. The inorganic filler is fixed to the glass fiber nonwoven fabric within a range of 30 to 30 t%. If it is less than 3 skin t%, it will not be possible to obtain satisfactory mechanical strength and dimensional stability when made into a laminate;
When the amount exceeds t%, the resin varnish impregnation rate becomes too low when preparing prepregs, which not only impairs electrical properties but also causes defects such as poor lamination and brittleness.

Preferably, it is fixed within a range of 30 to 12%. When a protective colloid agent is used, it is preferably used in an amount of 5 parts by weight or less based on the weight of the inorganic filler 10. If it is used in an amount of 5 parts by weight or more, the impregnating property of the eboxy resin varnish when preparing a prepreg is significantly reduced. As described above, the plate-like base material of the present invention contains glass fibers and an inorganic filler, thereby achieving amazing strength and dimensions that could not be achieved with conventional glass fiber nonwoven fabrics. A laminate with stability can be obtained.

Furthermore, applications other than laminates, such as FRP, FRTP, etc.
It can also be used as a composite material such as GRC, etc. as a reinforcing material for concrete by changing the glass fiber from E glass to C glass or alkali-resistant glass. EXAMPLES The present invention will be explained in more detail by giving Examples and Comparative Examples below.

Example Fiber diameter: 9〃, fiber length: 13 E-glass chopped strands of willow, easy to defibrate, 4 t%, fiber diameter: 10 strands, fiber length: 5 strands, easy to maintain the condition of 400 strands when boiled E
Paper was made by dispersing a mixture of chopped glass strands with 6% in white water at a concentration of 2%, and spraying the following solution with a saddle adhesive to obtain a glass fiber nonwoven fabric of 75%/conventional type.

Wind Adhesive compound composition Water-soluble epoxy resin
10 anchors - 1 part of glycidoxypropyltrimethoxysilane Next, the following 50
% concentration of dispersion 'B} to the nonwoven fabric.
A plate-like base material with a thickness of 150 mm was obtained by attaching 0 skin t%.

'B} Composition of dispersion calcium carbonate
10 Foundation acrylic acid ester
2 parts Next, this plate-shaped base material was impregnated with the following epixy resin varnish [q] and dried to obtain a prepreg with a resin ratio of 5 side t%, and 6 sheets of this prepreg were stacked and 35 pieces of copper foil was stacked on one side. Press molding was performed at 170 qo.

A single-sided steel-clad laminate with a thickness of 1.6 and a resin ratio of 55% was obtained. Composition of 'C' Epoxy Resin Varnish Epoxy resin (Epoxy equivalent weight 450-500) 10 parts Dicyandiamide 4 parts Penzyldimethylamine 0.2 parts Methylcetate.

Solp 3 Anchors Methyl ethyl ketone 3 Foundation comparative examples 1 Fiber diameter 9 French,
10 chopped strands of E glass on the fiber length 13 side
The mixture was dispersed in white water with a concentration of 0% and 2%, and after paper making, the mixture solution (2) was sprayed to apply an adhesive to obtain a glass fiber nonwoven fabric of 75 ta.

This glass fiber non-woven fabric was used as a base material and impregnated with the varnish of above 'C' and then dried to obtain a prepreg with a resin ratio of 75 wt%. 8 sheets of this prepreg were stacked and 35 pieces of copper foil were stacked on one side to form a 17 piece C. Press molding was performed to obtain a single-sided steel-clad laminate with a thickness of 1.6 and a resin ratio of 55 wt%. Comparative Example 2 The dispersion of [B'] was sprayed on the 75-thick glass fiber nonwoven fabric of Comparative Example 1, and 10 t% of the dispersion was deposited on the skin, and the spray was applied for 150 minutes/day.
That base material was obtained, and this base material was soaked with the above varnish and dried to obtain a Bripreg with a resin ratio of 65 wt%. 6 sheets of this prepreg were stacked and 35 piles of copper foil were layered on one side.
Press molding was performed at 0oo to obtain a single-sided copper-clad laminate having a thickness of 1.6 ribs and a resin ratio of 61 wt%.

The characteristics of the above Examples and Comparative Examples 1 and 2 are shown in the attached table.
The laminates obtained in the above examples have much better bending strength and normal and thermal dimensional stability than those of Comparative Examples 1 and 2, which are equivalent to or higher than those using glass woven fabric. The reliability of through-hole plating was also significantly improved.

In addition, in the attached table, the thermal expansion and contraction rate is 3000 to 150℃
These are the elongation rate in the thickness direction when heated to 150 °C and the shrinkage rate when cooled from 150°C to 30 qo.

Claims (1)

[Claims] 1. A nonwoven fibrous sheet is formed by bonding each constituent fiber of a mixed sheet with an adhesive, consisting of a defibrated single glass fiber and a glass fiber bundle formed by holding a plurality of glass fibers in a bundled state. 1. A plate-like base material comprising an inorganic filler fixed within a range of 30 to 300 wt%.