JPH03197042A - Preparation of laminated sheet - Google Patents

Abstract

PURPOSE:To make surface smoothness excellent and to increase adhesive force with a metal foil by providing a solventless liq. thermosetting resin compsn. layer wherein the wt. ratio of the ingredients is smaller than the wt. ratio of the compsn. ingredients between a laminated body of base materials impregnated with a solventless liq. thermosetting resin compsn. and a metal foil and heat-curing the compsn. layer. CONSTITUTION:In a laminate prepd. by laminating metal foils on one or both faces of a laminated body of base materials impregnated with a solventless liq. thermosetting resin compsn. (I1) wherein an epoxy resin (A1), a curing agent (A2) for the epoxy resin, a resin (B1) with a polymerizable unsatd. group, a polymerizable vinyl monomer (B2) and a polymn. initiator (B3) are incorporated and non-polymerizable solvent is not incorporated and heat-curing, a layer consisting of a solventless liq. thermosetting resin compsn. (I2) wherein (A1), (A2), (B1), (B2) and (B3) are incorporated, but non-polymerizable solvent is not incorporated and the wt. ratio of these ingredients [(B1)+(B2)+(B3)]/(A1)+(A2)] is smaller than the wt. ratio of the corresponding ingredients of the solventless liq. thermosetting resin compsn. (I1), is provided between the laminated body and the metal foil and is heat-cured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a laminate that is used for printed circuit boards and the like and has excellent surface smoothness and metal foil peel strength.

[Conventional technology]

A thermosetting epoxy resin and a resin having a polymerizable unsaturated group such as an epoxy vinyl ester resin or an unsaturated polyester resin are combined to create a solvent-free thermosetting resin composition that does not contain a non-polymerizable solvent. For example, a method for manufacturing a laminate in which a plurality of impregnated bodies impregnated into a glass fiber base material is stacked to obtain an impregnated base material laminate, and a laminate is manufactured by continuously heating and curing this is well known (for example, Kaihei l-2
00951).

In addition, at that time, the proportion of the thermosetting epoxy resin component in the impregnating resin composition used for the outer impregnated base material of the impregnated base material laminate is made larger than the resin component having a polymerizable unsaturated group. It has also been proposed to improve surface smoothness.

[Problem to be solved by the invention]

However, in order to obtain an impregnated base material laminate with a constant resin content in this method, it is necessary to adjust the resin content by passing the individual impregnated base materials through rolls etc. in advance and stack them with a stacking roll, or Since it is necessary to stack a predetermined number of impregnated base materials with excessive resin content and squeeze out the excess resin all at once using a squeeze roll, etc., the resin on both the top and bottom outside of the impregnated base material laminate is transferred to the roll. There is a problem that the amount of resin in this area tends to be insufficient due to adhesion and removal, and the surface smoothness of the resulting laminate and adhesive strength with the metal foil are not sufficient.

[Means to solve problems]

As a result of intensive research in view of this point, the present inventors formed a layer made of a resin composition containing more epoxy resin than the impregnating resin composition on one or both sides of the impregnated base material laminate to produce metal foil. It was discovered that a laminate with high surface smoothness and metal foil peel strength could be obtained by adhering, and the present invention was completed. That is, the present invention consists of an epoxy resin (A1) and a curing agent for epoxy resin ( A2) and a resin having a polymerizable unsaturated group (Bθ
and polymerizable vinyl monomer (B2) and polymerization initiator (B5)
A plurality of impregnated base materials (I [I) obtained by impregnating a fibrous base material (IF) with a solvent-free liquid thermosetting resin composition (II) containing no non-polymerizable solvent and containing no non-polymerizable solvent are laminated. Laminate (
■) After placing metal foil (V) on one or both sides of
In the method for manufacturing a laminate plate that is heated and cured, the laminate (IV)
and the metal foil <■), the above (AI), (A2), (B
snow), (B2) and (B5), and does not contain a polymerizable solvent, and the weight ratio of these components [(B1) 1) + (82) + (B5)) / [(Aθ
+(A2) ) is smaller than the weight ratio of the corresponding component of the solvent-free liquid thermosetting resin composition (II) by providing a layer made of the solvent-free liquid thermosetting resin composition (I2). The present invention provides a method for manufacturing a laminate, which is characterized by heat curing. At this time, the laminate (IV) and the metal foil (V
), it is also preferable to provide a layer of the solvent-free liquid thermosetting resin composition (I2), precure it by heating under substantially no pressure, and then heat and pressure mold it.

Next, the present invention will be explained in detail.

As the epoxy resin (AI) used in the present invention, either an epoxy resin that is liquid at room temperature or an epoxy resin that is solid at room temperature that melts into the polymerizable vinyl monomer (B2) at room temperature can be used alone or as a mixture.

Usually, an epoxy resin having an average epoxy equivalent of 100 to 400, preferably 100 to 250, which is liquid at room temperature, is used as the product component. Typical examples of epoxy resins (A1) include epoxy resins obtained from epichlorohydrin and dihydric phenols such as bisphenol A1 bisphenol F or resorcinol, polyglycidyl ethers of polyhydric alcohols, and polyglycidyl esters of polycarboxylic acids. , cyclohexene-based epoxy compounds, cyclopentadiene-based epoxy compounds, limonene dioxide, glycidyl ether ester of hydroxybenzoic acid, etc. Among them, epichlorohydrin and bisphenol A have a good balance of performance and are inexpensive. Epoxy resins that are liquid at room temperature obtained from and cyclohexene-based epoxy compounds that are liquid at room temperature are preferred because they provide low viscosity.

Further, these may be halogenated.

Furthermore, in the present invention, the powdered epoxy resin can be dissolved or dispersed in one or both of the liquid epoxy resin and the polymerizable vinyl monomer (B2) at room temperature.

Examples of the curing agent (A2) for epoxy resins used in the present invention include aromatic polyamines, polybasic acid anhydrides, latent curing agents such as boron trifluoride-amine complex (lli form), dicyandiamide, and its derivatives. , dibasic acid hydrazide, diaminomaleonitrile and its derivatives, melamine and its derivatives, amines, imides, polyamine salts, etc. Among them, polybasic acid anhydrides which are liquid at room temperature are particularly preferred.

Typical polybasic acid anhydrides include phthalic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, nadic anhydride, methylnadic anhydride, Trimellitic anhydride, pyromellitic anhydride, maleic anhydride, succinic anhydride, itaconic anhydride, citraconic anhydride, dodecenyl succinic anhydride, chlorendeic anhydride, benzophenonetetracarboxylic anhydride,
Cyclopentatetracarboxylic anhydride, 5-(2,5dioxotetrahydrofuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylic acid, ethylene glycol bistrimelitate anhydride or glycerin trimellitate anhydride, etc. These can be used alone or in a mixture of two or more. Among them, liquid ones are preferred, such as methylhexahydrophthalic anhydride, nadic anhydride, methylnadic anhydride, and the like.

In the present invention, various amines, salts thereof, curing accelerators such as metal complexes, and other additives can be added to the epoxy resin (^1) and the curing agent for epoxy resin (Am), if necessary.

A resin having a polymerizable unsaturated group used in the present invention (Bθ refers to a resin that has a radically polymerizable carbon-durium double bond and is cured by a radical polymerization reaction of the double bond,
Representative examples include epoxy vinyl ester resin,
Unsaturated polyester resin, urethane acrylate resin,
Examples include polyester acrylate resin, -diallyl phthalate, resin, spiran resin, and addition polymerization type polyimide. Among these, epoxy vinyl ester resins and/or unsaturated polyester resins are preferred, and epoxy vinyl ester resins are particularly preferred since they are excellent in heat resistance and adhesiveness to metal foil.

The epoxy vinyl ester resin includes various epoxy resins as mentioned above, preferably bisphenol type or novolank type epoxy resin, each singly or in a mixture, and an unsaturated basic acid as shown below. Examples include resins obtained by reaction in the presence of an esterification catalyst.

Here, typical unsaturated basic acids include acrylic acid, methacrylic acid, cinnamic acid, crotonic acid, monomethyl maleate, monopropyl maleate, monobutyl maleate, sorbic acid, and mono(2-ethylhexyl). These include malate, and these may be used alone or in combination in the form of a mixture of two or more types.

Further, examples of the unsaturated polyester resin include those obtained by reacting dibasic acids containing unsaturated dibasic acids with polyhydric alcohols. Typical unsaturated dibasic acids include maleic acid, maleic anhydride, fumaric acid, and halogenated maleic anhydride, and other typical saturated dibasic acids of type #1, which can also be called saturated dibasic acids. These include phthalic acid, phthalic anhydride, halogenated phthalic anhydride, isophthalic acid, terephthalic acid, tetrahydrophthalic anhydride, succinic acid, adipic acid, and sebacic acid.On the other hand, typical polyhydric alcohols include is ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1
．． 3-butylene glycol, 1,4-butylene glycol, neopentyl glycol, hydrogenated bisphenol A,
Examples include 1,6-hexanediol, adducts of bisphenol A and ethylene oxide or propylene oxide, glycerin, and trimethylolpropane.

In order to produce the above-mentioned epoxy vinyl ester resin or unsaturated polyester resin, it is sufficient to use the above-mentioned respective raw materials and follow conventionally known methods. It is also recommended to use a polymerization inhibitor for the purpose of adjusting the storage stability or curability of the product. Typical examples of such polymerization inhibitors include hydroquinone, pt-butylcatechol, and mono-dobutyl. Hydroquinones such as hydroquinone; hydroquinone 7-methyl ether,
Examples include phenols such as cresol; quinones such as p-benzoquinone, naphthoquinone, and p-torquinone; and copper salts such as copper naphthenate.

Examples of the polymerizable vinyl monomer (8 g) used in the present invention include styrene and its derivatives such as styrene, vinyltoluene, t-butylstyrene, chlorostyrene, or divinylbenzene; methyl (meth)acrylate;
Ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, 2-hydroxyethyl ( meth)acrylate, or low-boiling ester monomers of (meth)acrylic acid such as 2-hydroxypropyl(meth)acrylate, nitrimethylolpropane tri(meth)acrylate, diethylene glycol(meth)acrylate, 1,4-butanediol di(meth)acrylate; ) acrylate or (meth)acrylates of polyhydric alcohols such as 1,6-hexanediol (meth)acrylate, among others, styrene,
Vinyltoluene and low-boiling ester monomers of (meth)acrylic acid are preferred, and styrene is particularly preferred.

These polymerizable vinyl monomers can be used alone or in combination of two or more, but usually 60 to 80% by weight of the epoxy vinyl ester resin is used.
~20% by weight (total 100% by weight),
6 for 40-80% by weight of unsaturated polyester resin
It is used in a proportion of 0 to 20% by weight (total 100% by weight).

The polymerization initiator (B5) used in the present invention is preferably one that decomposes at a temperature lower than the heating and pressing temperature, such as cyclohexanone peroxide, 3.3.5-
) Limethylcyclohexanone peroxide, methylonexanone peroxide, 1.1-bis(t-butylperoxy) 3.3.5-) Limethylcyclohexane, cumene hydroperoxide, dicumyl peroxide, lauroyl peroxide , 3.5.5-
Trimethylhexanoyl peroxide, benzoyl peroxide, di-myristyl peroxydicarbonate, t-butylperoxy (2-ethylhexanoate), [-butylperoxy-3,5,5-trimethylhexanoate , t-butylperoxybenzoate, cumylperoxyoctonide, and other organic peroxides.

The solvent-free liquid thermosetting composition (I2) used in the present invention is used to form a resin layer on one or both sides of the impregnated base material laminate (IV) described below. (II) is used for impregnating the fibrous base material (■) described below, but all of the above (AI), (A2), and (B+
), (B2) and (R5) components as essential components,
Furthermore, additives such as a curing accelerator, internal mold release agent, pigment, filler, etc. may be added as necessary, and the composition does not substantially contain a non-polymerizable solvent, and has a fibrous base. Material (
Note that the solvent-type liquid thermosetting composition (I2) does not need to be able to be impregnated into the fiber base (II).

Here, the weight ratio (R2) of the essential components (AI), (A2), (Yamayama et al. and (B3)) of the solvent-free liquid thermosetting composition (I) [(B1)1)+ (82)+(85))/((AI
) 47 (A2) ) must be smaller than the weight ratio (R1) of the corresponding component of the solvent-free liquid thermosetting composition (I1).

Specifically, R2 is set to 1/99 to 40/60, especially 2
198 to 30/70 is preferable because shrinkage during curing is small and adhesiveness to metals, especially copper foil is excellent, and R1 is 5/95 to 70/30, especially 7793 to 60/70.
A value of 40 is preferable because it suppresses outflow of resin during molding and provides excellent adhesion between fibrous base materials.

In this way, when R1>92, the solvent-free liquid thermosetting composition (I1) contains a large amount of resin having a polymerizable unsaturated group, has excellent moldability, and has a solvent-free liquid thermosetting composition. Composition (I2) contains a large amount of epoxy resin component (has excellent adhesion to metal foil).

Typical examples of the fibrous base material (II) used in the present invention include glass fibers, carbon fibers, and aromatic polyamide fibers, with glass fibers being particularly preferred.
Among these, glass fibers include E-glass, C-glass, A-glass, S-glass, and D-glass in terms of their raw materials. can also be used.

These fibrous base materials (II) include rovings, chopped strand cloaks, continuous mats, cloths, nonwoven fabrics, roving cloths, surfacing mats, and chopped strands. The shape is selected depending on the intended use and performance of the molded product, and if necessary, a mixture of types or shapes on two sides may be used.

Among them, cloth and nonwoven fabric are preferred.

The fibrous base material (II) is impregnated with the solvent-free liquid thermosetting composition (I1) to produce an impregnated base material (I),
These impregnated base materials <m> are laminated to obtain an impregnated base material laminate (IV) by the method described below. It is appropriate to determine the ratio.

In order to obtain the above-mentioned impregnated base material laminate (IV), for example, the above-mentioned solvent-free liquid thermosetting composition (I1) is applied to the fibrous base material (II).
) is continuously impregnated, the amount of resin impregnated is adjusted using a squeeze roll, etc., and then a predetermined number of sheets are sandwiched between stacking rolls etc. and stacked, or the above solvent-free liquid thermosetting composition (if Iθ is Examples include a method in which a predetermined number of impregnated substrates (m) are prepared, and a predetermined number of sheets are overlapped, and at the same time, the excess amount of impregnation is squeezed out using a squeeze roll or the like to adjust the amount of impregnation.

When the impregnated base material laminate (IV) is produced in this way,
Since both outer surfaces of the impregnated base material laminate come into contact with wheel alignment rolls and squeeze rolls, a solvent-free liquid thermosetting resin composition adheres to these rolls, and this resin composition is applied from the outside of the impregnated base material laminate. Since a part of the material is removed, the resin composition tends to be insufficient on this outer side. In this state, the solvent-free liquid thermosetting composition (I2) is applied to one or both sides of the impregnated base material laminate (I), and the metal foil (V) described below is laminated thereon, or When a metal foil (V) coated with the solvent-free liquid thermosetting composition (I2) is laminated on one or both sides of the impregnated base material laminate ([1), the metal foil and impregnated base material laminate is formed. A layer of the resin composition having a constant thickness is formed between the bodies, and the shortage of the resin composition is replenished.

The thickness of this resin composition layer is not particularly limited, but is usually 2
A range of 0 to 150 μ- is preferred.

As the metal foil (V), for example, copper foil (electrolytic, rolled)
, aluminum foil, etc. When metal foil is used on only one side, a plastic film such as PET film, polyimide film, etc. that can withstand subsequent heat curing treatment is used as a cover film on the other side.

The impregnated base material laminate (IV) coated with the metal foil or cover film thus obtained is heated and cured to form a laminate, but at this time, the resin composition is kept under substantially no pressure so as not to flow out. It is preferable to pre-cure in a state of The pre-curing conditions include temperature conditions under which the resin (B1) having a polymerizable unsaturated group in the solvent-free liquid thermosetting composition (Iθ or (I2) mainly reacts). Although it depends on the polymerization initiator (B3) used, it is usually 80 to
The temperature is 140°C for 1 to 15 minutes. In the heating and pressing process, it is preferable to continuously heat and press the molding process between two pairs of endless belts, usually 130-190 t, preferably 14 t.
The temperature is 0 to 180°C. At this time, if necessary, post-curing may be further performed after the heat-pressing molding.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

Note that parts and percentages in the examples are based on weight.

Example 1 A solvent-free liquid epoxy resin with an epoxy equivalent of 190 obtained by the reaction of bisphenol A and epichlorohydrin (A, means belonging to A%).

42.8 parts of methyltetrahydrophthalic anhydride (A2), 0.26 parts of benzyldimethylamine (hardening accelerator), methacrylate of a phenol novolac type epoxy resin with an epoxy equivalent of 184 (
81) (70%) and styrene monomer (82) (30%)
%) was mixed with 0.42 parts of benzoyl peroxide (B5) to prepare a solvent-free liquid thermosetting resin composition (I,-1).

On the other hand, the above □epoxy resin with an epoxy equivalent of 190 (
A+) 48.2 parts, methyltetrahydrophthalic anhydride (
A2) Epoxy vinyl consisting of 41.8 parts, benzyldimethylamine 0.29 parts, phenol novolak type epoxy resin methacrylate (B+) with an epoxy equivalent of 184, (70%) and styrene monomer (82) (30%) A solvent-free liquid thermosetting resin composition (I2-1) was prepared by mixing 0.21 parts of benzoyl peroxide (B5) with 10 parts of the ester resin solution.

Next, four long glass cloths each having a thickness of 0.18 mm were individually impregnated with the solvent-free liquid thermosetting resin composition (I,-1) to obtain an impregnated base material (llll-1). At the same time as they are overlapped with a squeeze roll, the weight ratio of solvent-free liquid thermosetting resin composition (I, -1)/glass cloth is 4.
Excess solvent-free liquid thermosetting resin composition (I, -1) was squeezed out so that the amount of the impregnated base material laminate (IV
IV-1) was obtained.
) with a solvent-free liquid thermosetting resin composition (, I
2-1) were applied in the same amount.

At this time, the impregnated resin composition (I,-1) and (I,
The total amount of 1)/weight ratio of glass cloth was 43,157.

Further, 35 μ-electrolytic copper foil was pasted on both the upper and lower coated layers, kept in a hot air heating furnace set at 130°C for 5 minutes, then transferred to an endless belt press set at 170°C, and heated at 20 kgf/ci. The material was heated under pressure for 5 minutes, cut into predetermined dimensions, and then post-cured at 170° C. for 60 minutes to obtain a laminate with a resin content of 41% and a thickness of 0.8 fi.

The surface smoothness and copper foil peel strength of the obtained laminate were measured by the methods below. The results are shown in Table 1.

Surface smoothness: 5urfcos (5urfa) manufactured by Tokyo Seimitsu ■
ceTexture Measuring Instr.
The copper foil surface roughness (μm) of the laminate was measured using a laminate.

Copper foil peel strength: Measured according to JIS C-6481.

Examples 2 to 4 Solvent-free liquid thermosetting resin compositions (I,-2 to Wataru-4) and (I2-2 to 1r-4) having the compositions listed in the respective columns of Table 1. ) was used in the same manner as in Example 1 to obtain a laminate having a resin content of 41% and a thickness of 0.8 mm. This laminate was measured in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Examples 1 to 3 Same as Example 1 using solvent-free liquid thermosetting resin compositions (I, -1 to -1, -3) having the compositions listed in the respective columns of Table 1. Impregnated base materials (I'-1 to Iff'-3) were obtained by impregnating glass cloth, and the four sheets were stacked on top of each other with a squeeze roll, the amount of each composition was adjusted, and the amount of the composition was adjusted to the adjusted value. The weight ratio of /glass cloth was 43157, and the laminate (IV'-1~
■"-3) Lamination with a resin content of 41% and a thickness of 0.81fi in the same manner as in Example 1 except that the application of the solvent-free liquid thermosetting resin composition (I2) to the upper and lower surfaces was omitted. get a board,
Next, the results were measured in the same manner as in Example 1 and are shown in Table 1.

Table 1 Table 1 (Continued) [Effects of the Invention] According to the present invention, it is possible to obtain a laminate with excellent surface smoothness and strong adhesive strength with metal foil.

Heisei 1 December 26th

Claims (3)

[Claims] 1. Epoxy resin (A_1) and curing agent for epoxy resin (
A_2), a resin having a polymerizable unsaturated group (B_1), a polymerizable vinyl monomer (B_2), and a polymerization initiator (B_3)
A laminate consisting of a plurality of impregnated base materials (III) obtained by impregnating a fibrous base material (II) with a solvent-free liquid thermosetting resin composition (I_1) containing no non-polymerizable solvent and containing no non-polymerizable solvent. body(
After overlapping metal foil (V) on one or both sides of IV),
In the method for manufacturing a laminate plate by heating and curing, the above (A_1), (A_2), (
B_1), (B_2) and (B_3) and does not contain a non-polymerizable solvent, and the weight ratio of these components [(B_1) + (B_2) + (B_3)] / [(A_1
)+(A_2)] is smaller than the weight ratio of the corresponding component of the solvent-free liquid thermosetting resin composition (I_1). A method for manufacturing a laminate, which comprises the steps of: heating and curing the laminate as described above; 2. The laminate (IV) is a laminate obtained by laminating a plurality of sheets after adjusting the impregnation amount of the solvent-free liquid thermosetting resin composition (I_1) in the impregnated substrate (III) or a plurality of impregnated substrates (III). After laminating the sheets, a solvent-free liquid thermosetting resin composition (
The method for manufacturing a laminate according to claim 1, wherein the laminate is a laminate in which the amount of impregnation of I_1) is adjusted. 3. After providing a layer made of a solvent-free liquid thermosetting resin composition (I_2) between the laminate (IV) and the metal foil (V),
3. The method for producing a laminate according to claim 1, wherein the laminate is precured by heating under substantially no pressure, and then heated and press-molded.