JPH0299327A - Continuous preparation of laminated sheet - Google Patents

Abstract

PURPOSE:To obtain a laminated sheet containing no air bubble and high in the content of a base material by a method wherein a base material is partially impregnated with a resin solution so as to leave both side end parts thereof and the impregnated base material is heated under pressure while the penetration of the partially impregnated resin solution throughout the base material is achieved using a double belt press having substantially equal pressure over the whole region to be pressed. CONSTITUTION:A resin solution is partially infiltrated in each of a plurality of base materials at the central part thereof almost uniformly in the width direction thereof without fully filling the gaps of each base material 1 while both side parts each of which is 1-5% with respect to total area of the base material in the width direction thereof are left not to be impregnated. A plurality of the long base materials impregnated with the curable resin solutions are superposed mutually to be formed into a laminate. This laminate is heated under pressure by a double belt press 11 having substantially equal pressure over the entire region to be pressed and the impregnated resin heated under pressure fills the voids of the base materials as wide as possible to form a laminated sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for continuously producing a laminated board suitable for various electrical insulations, printed circuit boards, etc., in particular.

[Conventional technology]

A long base material such as kraft paper is sufficiently impregnated with thermosetting resin liquid without leaving any voids, and multiple sheets of this impregnated base material are stacked together and the resin liquid is cured by applying pressure or heating without applying pressure. It has been conventionally practiced to continuously manufacture laminates by using the same method.

However, among these methods, curing without pressure forms a thermosetting resin layer between the base materials, and the content of the base material in the resulting laminate is relatively low, resulting in poor strength and They tend to lack mechanical properties such as rigidity.

In order to solve this problem of insufficient base material content, there is a method in which multiple sheets of impregnated base materials that are sufficiently impregnated without leaving any voids are stacked together and cured under pressure using a double belt press, etc., as described above. , it is possible to increase the base material content and reduce the resin content, but most of the impregnated resin is discharged from the base material when pressurized, which tends to contaminate surrounding machinery, and the amount of discharge is huge, so it is difficult to discharge. Although it is necessary to recover the resin, there is the disadvantage that the task is extremely difficult.

[Problem to be solved by the invention]

Therefore, in the present invention, a long base material is impregnated with a thermosetting resin liquid, and a plurality of sheets of this impregnated base material are stacked and heated and pressed using a double belt press constituted by an endless belt. When obtaining a laminate with a large base material content,
The object of the present invention is to provide a method for manufacturing a laminate that does not discharge impregnated resin liquid to the pressurizing surface of equipment during pressurization, has substantially no residual air bubbles, and has a high base material content.

[Means to solve the problem]

In the present invention, a long base material is impregnated with a thermosetting resin liquid that essentially does not require a drying process and does not substantially generate reaction by-products such as gas or liquid during the curing reaction process. and a heating and pressing step of stacking a plurality of impregnated base materials and applying pressure to cure the resin liquid and integrate the resin liquid, in the impregnating step, a plurality of impregnated base materials For each base material, 1% to 5% of each side of the total area in the width direction of the base material is left unimpregnated. The partial impregnation is carried out almost uniformly with the resin liquid, and in the heating and pressurizing step, a double belt press constituted by an endless belt having substantially uniform pressure over the entire pressure zone is used to carry out the partial impregnation. The above problem was solved by applying heat and pressure while measuring the penetration of the resin liquid into the entire base material.

The present invention will be explained in detail below.

The elongated base material as used in the present invention is, for example, elongated glass fiber cloth, glass fiber-based material such as glass nonwoven fabric, kraft paper,
It refers to paper made mainly of cellulose fibers such as aluminum hydroxide mixed paper and linter paper, and sheets or strips made of inorganic fibers such as asbestos cloth. When using paper as a sheet-like base material, from the viewpoint of impregnability and quality, paper mainly composed of cellulose fibers with an air-dried density (bulk specific gravity) of 0.3 to 0.7 g/cc, such as kraft paper, is recommended. Paper is preferred.

Before impregnating these base materials with thermosetting resin liquid, they can be impregnated and dried using a treatment agent such as methylol melamine, methylol phenol, methylol guanamine, or N-methylol compound to improve their water resistance and absorb moisture. This is preferable because electrical properties can be improved by reducing the electrical properties. The amount of treatment agent attached here is the base material (10
0 parts by weight), it is usually 5 to 35 parts by weight.

In addition, the thermosetting resin liquid referred to in the present invention that essentially does not require a drying process and does not substantially generate reaction by-products such as gas or liquid during the curing reaction process is a conventionally known unsaturated polyester resin liquid. In addition to resins, diallyl phthalate resins, vinyl ester resins, and epoxy acrylate resins, these resins include side chain double bond type resins described below, and these have unsaturated groups in their molecules. These are resins that are characterized by being crosslinked between them or via crosslinking vinyl monomers, and also include epoxy resins.

These thermosetting resins are suitable because they are in a liquid state with low viscosity when impregnated into a substrate, and have good bonding properties with the substrate when cured after being impregnated into the substrate. The side chain double bond type resin has particularly excellent impregnating properties when used in combination with a crosslinking vinyl monomer.

The above-mentioned side chain double bond type resin is a polymer composed of a main chain and a side chain, and the main chain has vinylmore 7 having a functional group.
- It refers to a resin that is a backbone polymer containing units, and the side chain has a radically reactive carbon-carbon double bond formed through the functional group of the main chain, and the side chain double bond type The vinyl monomer units that make up the main chain of the resin are vinyl monomer units that have functional groups as essential units, and vinyl monomer units that do not have functional groups that are included as necessary. The main chain is composed of Monomers constituting the above essential units include vinyl monomers having a carboxyl group as a functional group such as acrylic acid, methacrylic acid, maleic anhydride, and maleic acid monoester;
Vinyl monomers having glycidyl groups as functional groups such as glycidyl methacrylate and glycidyl acrylate, and other functional groups such as allyl alcohol, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and N-methylolacrylamide. Vinyl monomers having a hydroxyl group are typical, and acrylic acid and methacrylic acid are particularly preferred.

Furthermore, the vinyl monomer unit having a functional group as used herein refers to the case in which it exists as an active functional group when the main chain is formed by polymerization, as well as the case in which the side chain described below is reacted with the functional group of the monomer in advance. A vinyl monomer unit with a functional group that serves to form a side chain into the main chain regardless of whether it is polymerized to form the main chain.

Examples of vinyl monomers without functional groups include styrene,
α-methylstyrene, chlorostyrene, vinyltoluene, vinyl chloride, vinylidene chloride, vinyl bromide, acrylonitrile, ethylene, propylene, butadiene, acrylic ester, methacrylic ester, vinyl acetate, vinyl propionate, diester maleate, ethyl vinyl Examples include benzene. The weight average molecular weight of the main chain composed of the vinyl monomer at position 1 is from 5,000 to 400,000, preferably from 10.000 to 200,000. This value is appropriately selected depending on the type of side chain. This molecular weight affects the physical properties and impregnability of the laminate for printed circuit boards or the laminate for electrical insulation.5. If it is less than 000, the mechanical properties of the cured laminate will be insufficient, and if it exceeds 400,000, the resin impregnation into the base material will be poor, both of which are not preferred. In addition, the amount of monomer units having functional groups in the main chain is related to the density of the side chains and affects the curing reactivity between side chains, so an appropriate ratio is selected, but the density of side chains in 1000 g of the main chain is O,1
-2 mol is preferable, and 0.4-1.5 mol is more suitable. The side chain referred to in this side chain double bond type resin has a double bond at the end or in the middle where >C=C,
The first term refers to those in which a technique is formed through a functional group in the main chain, but it is applicable if a crosslink can be formed between the side chains by a radical reaction using a crosslinking vinyl monomer.

Various methods can be employed to introduce a side chain having a double bond at the end of the side chain into the polymer constituting the main chain in this side chain double bond type resin. Some examples are as follows.

(a) One epoxy group of a compound having a jepoxy group, such as the diglycidyl ether type epoxy group of bisphere, is reacted with the carboxyl group of the functional group of the main chain, and the remaining epoxy group is reacted with acrylic acid or React with methacrylic acid.

(a) The carboxyl group of the main chain functional group and glycidyl acrylate or glycidyl methacrylate are subjected to an ester reaction.

(1) The epoxy group of the main chain functional group is subjected to an ester reaction with methacrylic acid or acrylic acid.

(1) A diisocyanate compound is reacted with hydroquine ethyl (meth)acrylate to prepare a reaction product containing monoisocyanate as the main component and containing almost no diisocyanate compound, and the isoneanate contained in this reaction product is converted into a main chain polymer. React the hydroxyl groups at.

In the exemplified method, the main chain was copolymerized first, but it goes without saying that the reaction for forming the side chain was first carried out, and these monomers were finally monopolymerized or copolymerized to form an acryloyl group at the end of the side chain. Alternatively, a side chain double bond type resin containing a methacryloyl group may be produced.

*t: Vinyl monomers for frame m include styrene, vinyltoluene, chlorostyrene, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate,
Included are butyl methacrylate, lauryl methacrylate, benzyl methacrylate, dibutyl maleate, dioctyl maleate, vinyl acetate, vinyl propionate, divinylbenzene, and the like. These monomers may be used in combination of two or more.

In addition, if necessary, halogen-containing flame retardant imparting ingredients and flame retardant aids such as phosphate ester, antimony trioxide, and aluminum hydroxide may be added to the thermosetting resin liquid used for impregnating the base material. It may also be used as

In addition, when using any thermosetting resin liquid, its viscosity can be appropriately selected depending on the purpose of use of the laminate to be manufactured, the pressure during pressure molding, etc., but it is usually 0.0001 at 25°C. Approximately 0.05 to 500 voise is suitable;
If it exceeds 0 voise, impregnating properties of the base material will be poor and air bubbles will tend to remain in the resulting laminate. Further, if it is less than 0.05 poise, the impregnating property is good, but there is a problem that it is easily affected by the intrusion of external air.

Then, the elongated base material is partially impregnated with such a thermosetting resin.

That is, the partial impregnation is carried out from 1% to 5% on each side of the total area in the width direction of each of the plurality of substrates.
% are left unimpregnated, and the center part is partially impregnated with the resin liquid almost uniformly in the width direction without filling all the voids in each base material. When kraft paper is used as an example of a base material, the porosity of kraft paper is usually 60 to 70% by volume (when air-dried), but if the porosity is, for example, 30 to 4%,
It is about 5% by volume and is impregnated only in the central part of the base material in the width direction so that it can be applied at any position in the impregnated part of the base material. If the unimpregnated portion is less than 1% on one side of the total area in the width direction, the discharged resin liquid will not be completely absorbed by the unimpregnated portion of the base material and will be discharged to the outside of the base material, contaminating the equipment. On the other hand, a content of 5% or more is not only unnecessary for absorbing the discharged resin liquid, but is also undesirable as it increases the loss of the base material and increases the width of the endless belt, leading to an increase in equipment costs.

Impregnation of the curable resin liquid into these elongated substrates is carried out by appropriately selecting a known method such as a partial coating method or a partial dipping method. For example, as shown in FIGS. 1 and 2, a plurality of base materials l... are sent out, and a partial coating nozzle 2...
・ Apply the resin liquid only to the center part of the base material 1 as described above to partially impregnate the base material 1, and as shown in FIG. 1, a resin-impregnated portion 3 at the center and resin-non-impregnated portions 4, 4 at both sides are formed to form an impregnated base material 5.

In addition, the amount of impregnation of the curable resin liquid is related to the pressure applied during the next process with the double belt press, and it is important to ensure that the pressure does not cause excessive flow to be discharged outside the base material and that the resulting laminate is Adjusted so that air bubbles are substantially absent, and the amount of resin liquid discharged from the base laminate to the unimpregnated portions at both ends when pressurized with a double belt press is 3% or less of the amount of cured resin in the product laminate; It is desirable that the amount is preferably 1% or less.

If the amount of impregnation is less than the appropriate amount for the pressure during pressurization, air bubbles will remain in the resulting laminate, causing an overall whitening phenomenon.

A plurality of long base materials impregnated with the curable resin liquid in this way are stacked together to form a laminate, and then pressed using a double belt press that applies substantially uniform pressure over the entire pressure zone. The impregnated resin is heated and pressurized to fill the voids in the base material as widely as possible to form a laminate.

The double belt press according to the present invention, which is composed of an endless belt that exerts substantially uniform pressure over the entire pressure zone, means, for example, that stainless steel endless belts with thicknesses of about lx and v are installed above and below. However, the base material impregnated with resin liquid is sandwiched between the upper and lower belts so that the base material can be heated and pressurized, and the structure is such that the pressure of the pressure band is substantially equal. To give a concrete example,
(1) A plurality of rows of roll pairs are arranged to sandwich the upper and lower belts and apply pressure to the belts, and the roll diameter is 50R11 or less and the ratio of roll pitch to roll diameter is 1.2 or less. This system reduces the pressure drop between adjacent rolls, and the position of the rolls may be fixed, or it may be placed between pressure plates installed above and below the endless belt, and the pressure plate It may revolve around it. If the diameter of the rolls becomes large and the distance between the rolls is too large, large waves will occur in the pressure applied to the substrate, which is undesirable.

(2) A type in which the upper and lower endless belts are sandwiched, a pressure plate is placed to apply pressure to the belt, and a pressure medium is press-fitted and circulated between the pressure plate and the endless belt for the purpose of lubrication.

(3) A container for storing the pressure medium is created by sandwiching the upper and lower endless belts, and the opening of this container is in contact with the endless belt, and the pressure medium directly presses the endless belt. This formula is particularly suitable because the pressure difference across the entire pressure zone is small.

What is shown in FIG. 1 is an example of this pressure medium storage type double belt press. This double belt press 11 includes drums 12, 128 and an endless belt 1.
3.13, a pressurizing chamber 14, and a pressure medium 15 made of high-temperature fluid, and the pressure medium supply device 16 is
A pump 17 and a heater 18 are connected by a plumbing pipe 19. Drums 12.12 and 12a, 12
a consists of a pair of upper and lower drums that rotate in opposite directions to each other along the traveling direction of the impregnated base material 5.
Drums 1 rotating in the same direction are arranged in parallel one behind the other on one side of the
Endless belts 13, 13 are each hung under tension between 2.12a.

Behind this endless belt 13.13, the impregnated base material 5... is cured of the resin impregnated with the impregnated base material 5...
A pressurizing chamber 14 is provided, which is filled with a pressure medium 15 for adding the heat and pressure necessary for the integration of.... This pressurizing chamber 14 is a container of any shape, and its structural surface is constituted by the endless belt 13. In this pressurizing chamber 14, an impregnated base material 5 is inserted from the endless belt 13.・Pressure medium 15 for applying heat and pressure to
is press-fitted. Furthermore, the pressurizing chamber 14 has a pressure medium 15
The pressure medium supply device 16 is configured by a pump 17 for supplying the pressure medium I5 and a heater 18 such as an electric heater for heating the pressure medium I5, which is piped by a piping vibrator 19.
is installed. Note that the heater 18 may be incorporated into this pressurizing chamber 14.

The pressure medium 15 is connected to this pressure medium supply device 16 and the pressurizing chamber 14.
The pressure medium 15 is circulated between the pressurizing chamber 14 by a pump 17, and the pressure medium 15 can be replenished, pressurized, and heated from outside the pressurizing chamber 14. The inside of the pressurizing chamber 14 is heated by a heater 18.
This can be done indirectly by heating the pressure medium 15 at . Furthermore, the same amount of pressure medium I5 flows out of the pressurizing chamber 14 as the endless belt 13.13 runs.
is sequentially supplied into the pressurizing chamber 14 by the pump 17, so that the pressure within the pressurizing chamber 14 is kept constant. And endless belt 13.
The impregnated base material 5 sandwiched between the impregnated base materials 5... is heated and pressurized by the pressure medium 15 injected into the pressurizing chamber 14, and the impregnated resin liquid spreads uniformly, fills the voids, and hardens. and become integrated. The pressure medium 15 may be any fluid as long as it exhibits fluidity under the operating conditions of the double belt press 11, but examples of these include air or nitrogen as a gas, and liquids such as nitrogen. Examples of waxes and low melting point polymers include polyethylene wax and paraffin, and examples of low melting point metals include solder and wood metal.

Regardless of the type of double belt press, the existence of a large pressure distribution, especially the existence of large pulsating pressure in the direction of movement, makes it difficult to selectively discharge air bubbles in the resin liquid-impregnated base material. In addition, air re-entry within the pressure zone is likely to occur and should be avoided, for example, if the pressure distribution is less than ±50% and ±5 kg/cf
f” or less is preferable.

Further, the applied pressure varies depending on the curable resin liquid used and the type of base material, but is appropriately selected in order to control the base material content in the resulting laminate. Usually 1 kfi
/ cz' G to l 00 ky/ cy" G, preferably 10 kg/ cttr' G to 50
9/cm"G.The pressure is l kg/cm"
When lower than G, not only is it difficult to increase the base material content, but also
The air evacuation effect is small, and the laminate is likely to have air bubbles mixed in.

On the other hand, a pressure higher than 100 kit/ax"G is not only unnecessary for removing air bubbles, but also causes the base material content in the resulting laminate to become too large, resulting in delamination, etc.
Tends to cause a decrease in strength.

Further, the temperature used for hot-press molding varies depending on the type of thermosetting resin liquid used, the type of curing catalyst, etc., but is generally in the range of 50°C to 200°C. At temperatures below 50°C, the time required for curing is too long and uneconomical;
When the temperature exceeds 00°C, problems such as internal distortion and foaming occur due to the rapid progress of curing.

When pressurizing with such a double belt press,
The resin liquid in the laminate of multiple base materials partially impregnated with the thermosetting resin liquid penetrates into the unimpregnated parts of the base materials under pressure, and is uniformly impregnated in the thickness direction of the laminate. The state will be as follows. This is because a large pressure gradient occurs in the laminate at the inlet of the double belt press in the opposite direction to the direction in which the laminate travels, and this pressure gradient promotes the penetration and impregnation of the resin liquid into the unimpregnated parts of the base material. This is presumed to be because the replacement between the bubbles remaining in the base material and the resin liquid is promoted. A portion of the displaced air bubbles are then continuously driven through the base material laminate in a direction opposite to the traveling direction, and continue to be removed from the laminate under pressure. In addition, some of the air bubbles are driven to both side edges of the laminate by the pressure gradient that also occurs in the width direction of the laminate, and the air bubbles are removed as a small amount of resin liquid is discharged from the non-resin-impregnated area. A laminate substantially free of air bubbles is obtained. Since the base material is partially impregnated with the thermosetting resin liquid, discharge of the resin liquid from the base material laminate can be completely eliminated even by applying pressure using a double belt press. In other words, since the base material can be partially impregnated with only the nail resin liquid corresponding to the resin in the resulting laminate, no excess resin liquid should be present in the laminate before pressurization. This is because if the resin liquid does not come out, there is no need to collect it in the double belt press.
Further, the double belt press is not contaminated, and the structure of the double belt press can be simplified. Therefore, as shown in FIG. 2, in the laminate after passing through the pressurizing chamber 14, resin hardened portions 6 are formed that are wider in both directions than the width of the resin-impregnated portion 3, and are wider than the non-resin-impregnated portions 4. Also, narrow non-resin-impregnated and non-cured portions 7, 7 are formed on both sides of the resin-cured portion 6.

The content of the base material in the laminate thus obtained varies depending on the base material used, the type of thermosetting resin liquid, pressurizing conditions, etc., but is usually in the range of 30% to 80% by weight. For example, when kraft paper is used as the base material and the above-mentioned m chain double bond type resin is used as the thermosetting resin liquid, the amount is preferably 35 to 65% by weight, and if it is less than 35%, the mechanical strength of the laminate will deteriorate. It is undesirable due to lack of strength and bending rigidity.
If it exceeds 65% by weight, it is disadvantageous that not only delamination is likely to occur, but also punchability and moisture resistance are reduced.

On the other hand, in order to manufacture metal foil-clad laminates, metal foil is overlaid on one or both sides of the laminate of impregnated base materials at the same time or a little later than the overlapping of the base materials, and this is fed to a double belt press. It will be done. The metal foil used here is electrolytic copper foil intended for use in printed circuit boards, and it is preferable to use this from the viewpoints of corrosion resistance, etching properties, and adhesion, but other metal foils include electrolytic iron foil and aluminum foil. is also used.

Metal foil having a thickness of 10 to 100 μm is usually used.

Moreover, it is more preferable that the adhesive surface of the metal foil is roughened for the purpose of improving adhesiveness.

In order to effectively achieve adhesion between the metal foil and the resin-impregnated substrate, it is preferable to use an adhesive. Semi-fluid, i.e. viscosity preferably 5
Adhesives having a pressure of 000 poise or less are suitable. From this point of view, for example, Evoquine-acrylate adhesive, epoxy resin adhesive, polyisocyanate adhesive, or various modified adhesives thereof are suitable.

As the epoxy adhesive, a mixture of a bisphenol A type epoxy 7 resin and a curing agent such as a polyamide resin or amines is suitable. By introducing such an adhesive, it is possible to produce a metal foil-clad laminate that has excellent adhesion strength of metal foil, as well as excellent solder heat resistance and electrical insulation properties.

When the adhesive is used in a state where it is applied to metal foil, it may be precured to a semi-cured state by heat treatment at 60 to 150°C for 2 to 7 minutes after application. The adhesive can also be applied to the laminate at the same time. The thickness of the adhesive film is 10
The thickness may be approximately -100 μm, and a thickness of 20 to 50 μm is particularly suitable.

The thickness of the laminate obtained by the present invention varies depending on the type of substrate, the composition of the thermosetting resin liquid, the use of the laminate, etc., but is usually 0.
5-3. OH is preferred.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples unless it departs from the gist of the present invention.

Throughout this specification, all temperatures are 0C, and parts and percentages are by weight unless otherwise specified.

(Preparation of side chain double bond type resin) A separable flask (300031) equipped with a stirrer, a thermometer with a gas introduction tube, a reflux condenser, and a dropping funnel.
12), methacrylic acid (35 g, 0.41 mol), methyl ethyl ketone (400 g), styrene monomer (80
0 g, 7.7 mol), azobisisobutyronitrile (5
, 0g) dodecyl mergabutane (12g) was charged, and polymerization was carried out at 75 to 80°C for 10 hours under a nitrogen atmosphere.

Hydroquinone (0.5 g) was added to inhibit polymerization. The polymerization rate of styrene monomer was 76%, and the polymerization rate of methacrylic acid was 93%, and a polymer-containing liquid containing a styrene-methacrylic acid copolymer having a weight average molecular weight of about 50,000 was obtained.

In addition, in another reactor having the same configuration as above, [Epicote 82
7J (trade name of epoxy resin, Yuka Ciel Epo Gyoshisha 1
) (360 g, 1 mol), methacrylic acid (138 g, 1 mol)
．． 6 mol), benzyldimethylamine (1.2 g), and parabenzoquinone (0.12 g) were charged, and the mixture was reacted at 120°C under a nitrogen atmosphere for 3 hours. After the reaction, the acid value became almost zero, and a vinylation reagent containing an epoxy resin containing an unsaturated group was obtained. Add the entire amount of the previously prepared polymer-containing liquid to the vinylation reagent, and add triphenylphosphine (5 g),
Rosebenzoquinone (0.10 g) was added and heated, the methyl ethyl ketone solvent was distilled off at a boiling point of 110°C, and the mixture was reacted at the same temperature for 5 hours.

After the reaction, the unsaturated group-containing epoxy resin is about 1
It became 5%. Heat evaporation was continued at 30-50ml!11g with intermittent addition of styrene monomer (1000g). The operation was terminated when the amount of methyl ethyl ketone detected in the distillate became 0.1% or less. The thus obtained resin liquid containing the curable prepolymer has a non-volatile content of 52
Viscosity consisting of 6% by weight. It was a yellow-brown liquid with I2 boils (25°C).

(Examples and Comparative Examples) Commercially available long kraft paper (basis weight 135 g/m' density 0.
Using 8 treated substrates impregnated with 20 parts by weight of N-methylolmelamine (Nikaresin S-305 manufactured by Nippon Carbide Co., Ltd.) in 100 parts by weight (49 g/c shoulder') and dried, After continuously impregnating the side chain double bond type resin liquid, unsaturated polyester resin liquid, and epoxy resin liquid in a predetermined manner and amount with a curing catalyst added, the outermost layer is coated with an epoxy resin adhesive if necessary. Electrolytic copper foils with a thickness of 35 μm were laminated, and they were continuously pressed and heated at 100°C for 5 minutes using a pressure medium-accommodating tuple belt press as shown in Figure 1, and further heated at +20°C for 1 hour. Table 1 shows the results of curing after a period of time to obtain a laminate and a single-sided copper-clad laminate. In addition, "partial impregnation (A)" of "impregnation method J" in Table 1 means that each of the eight base materials is impregnated with the thermosetting resin to the same extent as a whole, but the base material is Rather than impregnating the entire width with resin liquid, both ends are left unimpregnated using a coating device (slit nozzle).

"Partial impregnation (B)" means that by curving the base material into a U-shaped cross section during impregnation, the voids in the center of the base material are completely impregnated, and the resin liquid is completely impregnated on both sides of the base material. Laminated with non-impregnated materials.

"Complete impregnation" means that all eight substrates were completely impregnated by the dipping method.In addition, in all partial impregnations, the resin liquid was applied and impregnated to a shoulder width of 1030 J! with respect to a paper width of 1070 ffff.

As is clear from the results in Table 1, although partial impregnation of the thermosetting resin into the base material makes it possible to suppress the amount of resin liquid discharged during pressurization to an extremely small amount, the base material content It can be seen that a laminate with a high temperature can be obtained. In addition, Comparative Example 1 is the one in which the unimpregnated part cannot absorb the discharged resin, and Comparative Example 2 is the one in which the unimpregnated part cannot absorb the discharged resin.
Although partial impregnation is performed, the amount of resin impregnated in the entire base material is insufficient, Comparative Example 3 has insufficient impregnation due to insufficient pressure, and Comparative Example 4 has insufficient resin due to excessive pressure. This causes peeling and makes it impossible to obtain a good product.

〔Effect of the invention〕

As explained above, the method for continuously manufacturing a laminate of the present invention essentially does not require a drying process and substantially eliminates reaction by-products such as gas and liquid during the curing reaction process. an impregnation step of impregnating with a thermosetting resin liquid that does not generate
In a method for continuous production of a laminate including a heating and pressing step of stacking a plurality of impregnated base materials and heating and pressing them to cure the resin liquid and integrate them, in the impregnation step,
The resin liquid is partially impregnated into the base material leaving both side ends, and in the heating and pressing step, the part is impregnated using a double belt press having a substantially uniform pressure over the entire pressure zone. Since the method involves heating and pressurizing the impregnated resin liquid while measuring its penetration into the entire base material, there is a problem of contamination because all of the impregnated resin liquid discharged during pressurization with a double belt press is absorbed into both ends. It is possible to continuously produce a laminate with a high base material content that does not generate air bubbles and is substantially free of air bubbles.

[Brief explanation of drawings]

FIGS. 1 and 2 are schematic configuration diagrams showing an example of a manufacturing apparatus used in the present invention. ■...Base material, 2...Nozzle for partial application, 3...Resin-impregnated part, 4...Resin-non-impregnated part, 5... ... Impregnated base material, 11... Double belt press.

Claims (1)

[Claims] (1) A long base material essentially does not require a drying process;
In addition, there is an impregnation step in which a thermosetting resin liquid that does not substantially generate reaction by-products such as gas or liquid during the curing reaction process is applied, and a plurality of impregnated substrates are stacked and heated and pressurized to form a resin liquid. In the continuous manufacturing method of a laminate, which includes a heating and pressing step of curing and integrating the materials, in the impregnation step, 1% of each side of the total area in the width direction of each of the plurality of base materials is added. 5% of both sides are left unimpregnated, and the central part is partially impregnated with the resin liquid almost uniformly in the width direction without filling all the voids of each base material, and in the heating and pressing process, the entire area of the pressure band is impregnated. Using a double belt press consisting of endless belts that exerts substantially uniform pressure across the substrate, the base material of the resin liquid is heated and pressurized while measuring the penetration of the partially impregnated resin liquid into the entire base material. A method for continuously manufacturing a laminate, characterized by eliminating discharge to the outside of the material. (2) The continuous production method of a laminate according to claim 1, wherein the laminate is a metal foil-clad laminate formed by laminating a plurality of base materials impregnated with metal foil simultaneously or in a separate process. (3) A double belt press consisting of an endless belt that has a substantially uniform pressure over the entire pressure zone, has a pressurizing chamber with the endless belt as one constituent surface, and uses a fluid as a pressure medium. The method for continuously manufacturing a laminate according to claim 1, which is a double belt press. (4) The method for continuously manufacturing a laminate according to claim 1, wherein the pressure in the heating and pressing step is in the range of 1 to 100 kg/cm^2. (5) The method for continuously manufacturing a laminate according to claim 1, wherein the base material is paper.