JPH03114831A - Impregnation/superposition method and production of laminated sheet - Google Patents

Abstract

PURPOSE:To enhance resistance to solder of a laminated sheet by a method wherein, after fibrous base materials are compressed and deaerated, the same is impregnated with a resin liquid while being released from compression in the resin liquid, and thereafter, the fibrous base materials are laminated in the resin liquid. CONSTITUTION:After a plurality of sheets of fibrous base materials 1 are superimposed one on another by guide rolls 2, they are led into an impregnating bath 4 containing a resin liquid while being compressed and deaerated by compression rolls 3 and are released from compression to be separated by guide rolls 2' within the impregnating bath 4 containing the resin liquid to the individual fibrous base materials which are impregnated with the resin liquid. After the individual resin liquid-impregnated base materials are then superimposed one on another and the amount of the resin liquid with which the base materials are impregnated is adjusted by squeezable seal rolls 5 located under a resin liquid level at the side part of the impregnating bath 4 containing the resin liquid, the superimposed fibrous base material is led into ambient air to be laminated with metallic foils or cover films 7 by laminating rolls 6, and by hardening the same under heating, a desirable laminated sheet is obtained. By this method, resistance to solder and insulating properties of the laminated sheet can be enhanced.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a method for impregnating and laminating fibrous base materials suitable for obtaining a void-free laminate, and a method for producing a laminate using this method. It is related to.

[Conventional technology]

In the method of continuously manufacturing laminates using resin liquid,
Conventionally, a long fibrous base material is continuously impregnated with resin to obtain a resin-impregnated base material, and then a predetermined number of these base materials are stacked in the atmosphere, and if necessary, metal foil is attached to both the top and bottom surfaces. A manufacturing method using heat molding has been proposed.

[Problem to be solved by the invention]

However, in the above method of laminating resin-impregnated base materials in the atmosphere, air is likely to be drawn in when the base materials are laminated, resulting in voids in the resulting laminate, resulting in poor solder resistance of the laminate. It has the disadvantage of lowering the

[Means to solve the problem]

The inventors of the present invention conducted intensive research in view of the above situation, and found that after compressing and deaerating a fibrous base material, the resin was released into the fibrous base material while being released from compression in a resin liquid. Impregnated with liquid,
Next, when the fibrous base materials are laminated in the resin liquid, the impregnating property of the resin into the fibrous base materials is improved, and air entrainment can be prevented when the base materials are laminated. The inventors have discovered that the generation of voids in the board is suppressed and the solder resistance of the laminate is significantly improved, leading to the present invention.

That is, in the present invention, after compressing and deaerating a fibrous base material, the fibrous base material is impregnated with a resin liquid while being released from compression in a resin liquid, and then the fibers are soaked in a resin liquid. A method for impregnating and overlapping fibrous base materials, which is characterized by overlapping fibrous base materials, and compressing and deaerating the fibrous base materials, and then releasing the fibrous base materials from compression in a resin solution. The present invention provides a method for manufacturing a laminate, which comprises impregnating a base material with a resin liquid, then superimposing the fibrous base materials in the resin liquid, and then heating and curing the fibrous base materials.

Examples of the fibrous base material used in the present invention include kraft paper, linter paper, glass cloth, glass nonwoven fabric, etc., and these can be used alone or in combination.

The resin liquid used in the present invention may be one that is thermosetting and can be impregnated into a fibrous base material (such as a solid resin dissolved in a solvent or a solid component dispersed in a liquid). For example, solvents containing phenolic resins, melamine resins, epoxy resins, polyimide resins, unsaturated polyester resins, epoxy vinyl ester resins, diallyl phthalate resins, etc. as main components. Examples include liquid resin compositions containing or not containing it.

Among these, epoxy resins, unsaturated polyester resins, epoxy vinyl ester resins, etc. that do not produce by-products such as condensed water during curing are preferred, and compositions containing no solvents (with the exception of polymerizable vinyl monomers such as styrene) are preferred. It is particularly preferable that it is a material.

These resins may be used alone or in combination.

In addition, when a solvent is used as a diluent, it is necessary to remove the solvent in the base material before the metal foil or cover film is bonded to the outermost layer.

Examples of metal foil include long copper foil, aluminum foil,
Brass foil, stainless steel foil, nickel foil, etc.

is used, and an adhesive may be applied to the back surface if necessary.

Further, as the cover film, for example, polyethylene film, polypropylene film, polyester film, polyfluoroethylene film, polyimide film, etc. are used.

Next, examples of the impregnation/superposition method of the present invention are shown in Figures 1 to 3.
This will be explained in detail using .

After stacking a plurality of fibrous base materials 1 with guide rolls 2, they are compressed with compression rolls 3 and guided into the resin liquid impregnating tank 4 while being deaerated, and then released from the compression and guided into the resin liquid impregnating tank 4. The resin liquid is impregnated into each of the fibrous base materials while separating them individually using guide rolls 2. At this time, it is also possible to use a plurality of compression rolls 3 to compress the long base material one by one, but this would prevent the resin liquid from leaking from the compression rolls 3 and reduce the capacity of the resin liquid impregnation tank 4 as much as possible. From this point of view, it is preferable to use a method in which a plurality of fibrous base materials are simultaneously compressed using as few compression rolls 3 as possible.

Next, the impregnated base material impregnated with the resin liquid is transferred to the resin liquid impregnation tank 4.
After overlapping with a seal roll 5 that can be squeezed below the liquid level on the side and adjusting the amount of resin liquid impregnated, the resin is brought out into the atmosphere, and a metal foil or cover film 7 is pasted with a lamination roll 6. Combine and heat cure (not shown)
, to obtain the desired laminate. At this time, the impregnated base materials may be overlapped in the resin liquid using a roll (not shown) other than the seal roll 5, and then introduced to the seal roll 5.

In addition, it is not necessary to adjust the amount of resin liquid impregnation of the superimposed impregnated base materials with the seal roll 5, and after superimposing them, a squeeze roll (not shown) outside the resin liquid impregnation tank 4 is used.
The amount of resin liquid impregnated may be adjusted by Moreover, after passing through the above-mentioned squeezeable seal roll 5, it is preferable to readjust by passing it through another squeeze roll (not shown). Heat curing is performed without pressure or under pressure, but pressureless heat curing is Pressure and heat curing may be combined.

Furthermore, in the method of the present invention, as shown in Figure 2, the resin liquid impregnation tank 4 is of a closed type, and the inside of the tank is reduced in pressure by the pressure reducing device 8, thereby reducing resin leakage from the compression roll 3 and seal roll 5. , and is preferable from the point of view of removing air brought into the resin liquid.In this case, if the degree of pressure reduction is too high, air may flow in from the compression roll 3 or the stacking roll 5, and low boiling point components in the resin may be removed. In order for the vapor to evaporate,
Usually, it is carried out at a reduced pressure of 10 to 700w + dg,
Among these, 50 to 550 mmHg is preferred. Alternatively, as shown in Figure 3, the fibrous base material may be degassed under reduced pressure in advance and then compressed.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples shown in FIGS. 1 and 4. In addition, parts are parts by weight,
% indicates weight %.

Example 1 Epoxy resin 16 having an epoxy equivalent of 190 obtained by the reaction of bisphenol A and epichlorohydrin.
9 parts, 26.5 parts of an epoxy resin with an epoxy equivalent of 370 obtained by the reaction of tetrabromobisphenol A and epichlorohydrin, 26.6 parts of methyltetrahydrophthalic anhydride, 0.7 parts of benzyldimethylamine, tetrabromobisphenol A Methacrylate (60%) of an epoxy resin with an epoxy equivalent of 370 obtained by reaction with epichlorohydrin and styrene monomer (
40%) and 30.6 parts of a polymerization initiator manufactured by "Perhexa 3M" [NOF a1) were mixed to prepare a room temperature solvent-free liquid thermosetting resin. The viscosity of this was 650 cps and the bromine content was 20%.

This will be explained below with reference to Figure 1. Four long fibrous substrates 1 made of glass cloth with a thickness of 0.18 mm and a width of 1020 ann were stacked on each other with a guide roll 2 and then compressed with a compression roll 3. The compressed fibrous base material 1 is guided into the resin liquid impregnation tank 4 containing the above room temperature solvent-free liquid thermosetting resin, and the fibrous base material is individually separated by guide rolls 2' while being released from compression. The resin liquid content is 42% while being impregnated with the resin liquid and overlapped with the seal roll 5 that can be squeezed.
I squeezed it to make it.

Next, copper foil 7 with a thickness of 35 μm was laminated to the upper and lower surfaces of the laminated impregnated substrates using a laminating roll 6, and after precuring for 3 minutes in a hot air heating oven at a temperature of 120°C, the copper foil 7 was heated at 170°C.
It was heated and pressed using a continuous double belt for 10 minutes at a pressure of 20 kg/cm'' and then cut.

Then, it was post-cured at 170°C for 60 minutes without pressure.
A laminate of 000 x 1000 x O, 8 m was obtained.

The resulting laminates were evaluated for the presence or absence of voids and for their solder resistance after a pressure puller test (hereinafter abbreviated as PCT) using the following methods. The results are shown in Table-1.

0 Presence or absence of void generation: The copper foil was removed by etching with a cupric chloride aqueous solution, and the presence or absence of void generation was determined using a microscope.

Solder resistance after OPCT: After removing the copper foil from one side by etching, the sample was allowed to absorb water in a pressure cooker at 120°C, 2 atm, and for 4 hours, then the moisture on the surface was wiped off, and the sample was placed in a soldering bath at 260°C. Float for 2 minutes,
The presence or absence of delamination and measling was visually measured.

Comparative Example 1 As shown in Figure 4, a long fibrous base material 1 was introduced into a resin liquid impregnation tank 4, impregnated with the same thermosetting resin as in Example 1, and then transported through the atmosphere. After degassing the air remaining in the base material, the resin liquid content was adjusted to 42% while being overlapped with a squeeze roll 5', and thereafter a laminated N plate was obtained in the same manner as in Example 1. In the same manner, the presence or absence of void generation and the solder resistance after PCT were determined. The results are shown in Table-1.

Table 1 [Effects of the Invention] The laminate obtained by the impregnating and laminating method of the present invention is similar to the laminate obtained by impregnating with a conventional dip method or other impregnating method and laminating the impregnated base materials in the atmosphere. In comparison, it has good impregnating properties and there is no air entrainment during stacking, so it has particularly excellent solder resistance and insulation properties, and is useful as a method for continuous production of laminates.

[Brief explanation of drawings]

FIGS. 1 to 3 are schematic diagrams showing the impregnation/superposition method of the present invention, and FIG. 4 is a schematic diagram showing the conventional impregnation/superposition method. 1: Long fibrous base material, 2.2' Ni guide roll,
3: Compression roll, 4: Resin liquid impregnating tank, 5: Seal roll capable of being squeezed, 5' squeeze roll, 6: Lamination roll, 7: Metal foil or cover film, 8: Decompression device.

Claims (1)

[Claims] 1. After compressing and deaerating the fibrous base material, impregnating the fibrous base material with the resin solution while releasing the compression in the resin solution, and then impregnating the fibrous base material with the resin solution in the resin solution. A method for impregnating and overlapping fibrous base materials, which comprises overlapping the fibrous base materials. 2. The impregnation/superposition method according to claim 1, wherein the impregnation with the resin liquid is carried out in the resin liquid under reduced pressure. 3. Claim 1 or 2, in which a plurality of fibrous base materials are piled up, compressed and deaerated, and then separated into individual pieces while being released from compression in a resin liquid, and then piled up again in a resin liquid. The impregnation/superposition method described. 4. After compressing and deaerating the fibrous base material, impregnate the fibrous base material with the resin liquid while releasing the compression in the resin liquid, and then impregnate the fibrous base material in the resin liquid. A method for producing a laminate, which is characterized by heating and curing after stacking. 5. The method for manufacturing a laminate according to claim 4, wherein the impregnation with the resin liquid is carried out in the resin liquid under reduced pressure. 6. Claim 4 or 5, in which a plurality of fibrous base materials are piled up, compressed and deaerated, and then individually separated while being released from compression in a resin liquid, and then piled up again in a resin liquid. Manufacturing method of the described laminate.