JPS5885593A - Paper substrate material metal foil-covered laminated board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention has excellent peel strength of metal foil at room temperature and high temperature,
The present invention also relates to a paper-based metal foil-clad laminate that has excellent solder heat resistance, electrical insulation, etc., and is less likely to warp or twist.

The metal foil laminate used for printed circuit boards is 260
It is required to have excellent heat resistance against soldering temperatures that reach up to °C, excellent electrical insulation properties, and peel strength of metal foil. In addition, in recent years, the density and speed of printed wiring board processing have rapidly increased, and high reliability is required in the soldering dip process, the component mounting process using a soldering iron, and the like. In this process, the metal foil is often exposed to stress in a high temperature range corresponding to the solder melting temperature, which tends to cause the metal foil to peel off. Therefore, peel strength is required to prevent the metal foil from peeling off in a high temperature range corresponding to the solder melting temperature. It is required that large warpage does not occur in the size printing process, heating process, or automatic parts cutting process, and that the warpage is extremely small.

For this reason, the present inventors previously proposed in Japanese Patent Application Laid-Open No. 56-8227 that an adhesive was used to improve the adhesion between a curable resin and metal foil that did not generate by-products such as gas or liquid during the curing reaction process. We proposed the use of amine-curing epoxy resin.

In this case, the amine-curing epoxy resin was shown to exhibit well-balanced performance as an adhesive for printed circuit boards, including peel strength for metal foil, soldering heat resistance, and electrical insulation properties.

However, in the metal foil-clad laminate using an amine-curing epoxy resin adhesive, the metal foil tends to peel off when stress is applied in a high temperature range corresponding to the solder melting temperature. When the peeling state of the metal foil at this high temperature was observed using a scanning electron microscope, it was found that it was cohesive failure within the adhesive layer.

The inventors of the present invention have conducted further studies to solve this problem, and have found that by adding a certain amount of inorganic filler to the amine-curing epoxy resin adhesive, the above-mentioned drawbacks can be eliminated and the warpage can be improved. It was discovered that a metal foil-clad laminate with less twisting can be obtained, leading to the present invention.

The present invention comprises a plurality of paper base layers impregnated with a curable resin that does not substantially generate reaction by-products such as gas or liquid during the curing reaction process, and a paper base layer laminated on at least one surface of the paper base layer with an adhesive layer interposed therebetween. In a metal foil-clad laminate for a printed circuit board having a metal foil, the adhesive layer is made of an amine-curing epoxy resin containing 10 to 200 parts by weight of an inorganic filler based on 100 parts by weight of the resin, and the adhesive layer The present invention relates to a paper-based metal foil-clad laminate, characterized in that the thickness of the layers is in the range of 5 to 150/'m.

Inorganic fillers used in the present invention include metal oxides, -5-〇〇 metal hydroxides, metal carbonates, clay minerals, and silicate minerals. Examples of metal oxides include silica, magnesium oxide, aluminum oxide, zinc oxide, titanium oxide, and iron oxide. Examples of metal hydroxides include aluminum hydroxide and magnesium hydroxide. Examples of metal carbonates include, for example. Examples of clay minerals include kaolin, montmorillonite, talc, mica, their fired products, and those surface-treated with organic silane, and examples of silicate minerals include carunium silicate. , magnesium silicate, aluminum silicate, potassium aluminum silicate, etc. A mixture of two or more types of inorganic fillers may also be used.

The average particle size (Cso) of these inorganic fillers is preferably 10 Lm or less, preferably 2/LrrL or less.

If it exceeds 10 .mu.m, there is a risk that the filler will separate and settle in the adhesive, and the wettability of the adhesive to fine irregularities on the surface of the metal foil cloak will be particularly impaired.

These inorganic fillers are blended in an amount of 5 to 200 parts by weight, preferably 10 to 100 parts by weight, more preferably 20 to 60 parts by weight, per 100 parts by weight of the epoxy resin. If it is less than 5 parts by weight, the effect is generally poor, and if it exceeds 200 parts by weight, the peel strength of the metal foil decreases and the thermal properties of the solder side during heat absorption are impaired.

Furthermore, it is preferable for the inorganic filler to have a hardness of 5 or less on the Mohs scale. If the Mohs hardness is higher than 5, there is a risk of wear and damage to the die during punching, so care must be taken. .

Among these inorganic fillers, clay minerals have a layered structure, which is thought to improve the cohesive failure strength when peeling off metal foil, and among metal oxides, magnesium oxide has an unsaturated hardening resin. In the case of polyester resin, it is thought that it also improves the adhesion between the impregnated base material laminate and the adhesive layer, and both are preferred.

As proposed by the present inventors in Japanese Patent Application No. 55-133249, in order to obtain a metal foil-clad laminate with improved warpage and twisting, the average residual stress of the adhesive layer of the metal foil-clad laminate is improved. Among these inorganic fillers, plate-shaped fillers such as talc and kaolin are particularly effective in reducing the average residual stress of the adhesive layer.
Therefore, the effect of improving warpage and twisting is significant.

Furthermore, by incorporating an inorganic filler, it is expected that the solvent resistance of the adhesive layer will be improved.

The epoxy resin used as an adhesive in the present invention is
Compounds having bifunctional or more epoxy groups, such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolak type epoxy resin, alicyclic type epoxy resin, etc., are used singly or in a mixture of two or more types. be able to.

Amine-based hardeners are used as hardeners for epoxy resin adhesives. Examples include aliphatic holamines such as ethylenediamine, diethylenetriamine, triethylenetetramine, hexamethylenediamine, polyoxypropylenediamine (N-aminoetherpiperazine, menthendiamine, inphoronediamine, bis(4-amino-3- Alicyclic polyamines such as methyl (7 chlorohexyl) methane; aromatic polyamines such as metaphenylene dianine and diaminodiphenylsulfone; and polyamide amines synthesized from dimer acid and aliphatic polyamines such as ethylenediamine. Mixtures may also be used.

The use of an acid anhydride for curing the epoxy resin of the adhesive layer is disadvantageous because it requires the use of a solvent, a high reaction temperature, or a long reaction time.

! , compounds having trifunctional or more functional epoxy groups, such as tetraglycidyl-1,3-bisaminomethylcyclohexane, triglycidylisonanurate, etc., are used in combination with difunctional epoxy compounds, resulting in poor performance of metal foils at high temperatures. Peel strength is improved. However, since warping and twisting of the metal foil-clad laminate tends to increase, the blending of the inorganic filler is particularly important in this case.

The adhesive can be applied to the metal foil using an appropriate device such as a normal roll coater, blade coater, or wire bar coater. The thickness is 5 to 150/
zyn, preferably adjusted to a range of 30 to 80 μm. If this thickness is less than 5 mm LrrL, the soldering heat resistance may deteriorate, and if it exceeds 1501 Lm, an adverse effect may appear on the warp of the metal foil-clad laminate, or cracks may occur in the adhesive during punching. , the metal foil tends to sink into the hole more often.

In the present invention, the resin used for impregnating the paper base material is a curable resin that does not substantially generate reaction by-products such as gas or liquid during the curing reaction process, such as unsaturated polyester resin, diallyl phthalate resin, etc. Includes radical polymerization types such as bamboo vinyl ester resins, and addition reaction types such as epoxy resins.

Resins that produce reaction by-products such as gas or liquid require high molding pressure during curing because the by-products can damage the bond between the adhesive layer and the resin layer, and metal foiling is not possible in a continuous method. It is unsuitable as a resin for manufacturing laminates. On the other hand, with the above resin, the required number of long base materials are impregnated with resin liquid while being continuously supplied, and then they are stacked on top of each other, metal foil coated with adhesive is laminated, and then hardened under no pressure. It is suitable for manufacturing metal foil-clad laminates by the so-called pressureless continuous method.

Among these, unsaturated polyester resins include those whose unsaturated polyester chains have the structural formula shown below, and flame-retardant resins in which halogen is introduced into the polyester chains. Therefore, the raw polyols of unsaturated polyester include ethylene glycol, propylene glycol, diethylene glycol, ], ]4
-Butanediol 1,5-bentanediol, bisphenol A propylene oxide adduct, 2,2-dibromoneopetyl glycol, etc. Saturated polybasic acids include phthalic anhydride, isophthalic acid, terephthalic acid, adipic acid, azelaic acid, chloro Unsaturated polybasic acids such as endo acid, tetrabromo phthalic anhydride, and tetrachlorophthalic anhydride, as well as maleic anhydride and fumaric acid, are generally used as a mixture of these and a crosslinking monomer.

Also, so-called vinyl ester resins, which are mixtures of epoxy acrylates having two or more acryloyl or methacryloyl groups at the ends and crosslinking monomers, and mixtures of diallyl phthalate resins and crosslinking monomers, which have the structural formula of, for example, can also be used.

Styrene is commonly used as a crosslinking monomer, but other examples include α-methylstyrene, vinyltoluene, chlorostyrene, divinylbenzene, alkyl acrylate or methacrylate having 1 to 10 carbon atoms, diallyl phthalate, triallyl cyanurate, etc. Monomers can also be used.

Organic peroxides are commonly used as curing catalysts for radically polymerizable curable resins, and in particular, peroxyketals, peroxyketals, and peroxides are used as catalysts for curing radical polymerization type curable resins. One or several types of peroxides selected from esters and dialkyl peroxides are preferred from the viewpoint of solder heat resistance, electrical connection properties, and peel strength of metal foil.

Therefore, preferred catalysts include peroxyketals such as 1,1-bis(t-butylperoxy)-3,
3,5-)limethylcyclohexane, 1,1-bis(t
-butylperoxy)cyclohexane, n-butyl-4
, 4-bis(t-butylperoxy)valerate, peroxy esters such as t-butylperoxyacetate, t-butylperoxy-2-ethylhexanoate, t-butylperoxylaurate, t-butylperoxyester. Examples of oxybenzoate and dialkyl peroxide include di-t-butyl peroxide and 2,5-dimethyl 2+ 5 y (t-butylperoxy)hexyne-3. Curing by heating is common, but
Curing by light, electron beam, or radiation can also be used.

The epoxy resin used for impregnating the base material is preferably a bisphenol A type, and the curing agent is not limited to the amine curing agent for the epoxy resin used as the adhesive described above, but liquid acid anhydrides can also be used. can.

The resin composition used for impregnating the base material may also contain various fillers, colorants, flame retardants (reactive type and additive type),
Flame retardant aids may be included.

Examples of the paper base material used in the present invention include kraft paper, linter paper, and mixed paper thereof.

As the metal foil, electrolytic copper foil, rolled copper foil, aluminum foil, electrolytic iron foil, etc. are used.
As proposed in No. 8136, applying a surface treatment agent, especially a silane coupling agent, to the surface of the metal foil before applying adhesive to the metal foil will result in a product with even better peel strength. Obtainable. As the silane cupping agent, any of those generally used for joining surfaces of inorganic and organic materials can be used, but alkoxysilanes having an epoxy group, an amino group, or a norcapto group are preferred.

The metal foil-clad laminate of the present invention can be manufactured by either batch method-1 or bamboo continuous method.
As mentioned above, it is particularly advantageous to produce in a pressureless continuous manner. It is also possible to manufacture the metal foil-clad laminate of the present invention by manufacturing the resin laminate portion in advance in a continuous manner and then laminating the metal foil in a batch manner.

The metal foil-clad laminate obtained by the method described above is applicable not only to single-sided metal foil-clad laminates but also to double-sided metal foil-clad laminates. It has excellent heat resistance, electrical insulation, etc., has little warping and twisting, and fully satisfies the automation and labor-saving demands of printed wiring board processing manufacturers and set manufacturers.

Next, the present invention will be explained by examples.

Example 1 Melamine resin (Nikaresin 305 manufactured by Nippon Carbide Industries)
) and a commercially available kraft paper (MKP-150 manufactured by Tomoe Paper Industries) pretreated with a suspension of a mixture of oleyl alcohol.
1,1-bis(t-butylbaoxy'/)-313,5-) was added as a curing catalyst to 100 parts by weight of a commercially available unsaturated polyester resin (Polymer 6305 manufactured by Takeda Pharmaceutical Co., Ltd.) while continuously conveying five sheets of A commercially available electrolytic copper foil was impregnated with a resin solution containing 1 part by weight of methylcyclohexane (Perhexa 73M, manufactured by Nihon Yushi Co., Ltd.), overlapped using two pairs of rolls, and continuously unwound. A 1% ethanol solution of γ-glycidoxypropyltrimethylsilane (Union Carbide A) 87) as a 7-run coupling agent was applied thinly to T-7) manufactured by Fukuda Metal Foil Industry Co., Ltd., and then continuously dried. In addition, as an adhesive, bisphenol-type epochino resin (Epicoat 828 manufactured by Shell Chemical Co., Ltd.) having an epoxy equivalent of 190, isophorone diamine having an active hydrogen equivalent weight 41, and calcined kaolin (Tenton Bane manufactured by Hayashi Kasei Co., Ltd.)) were added in a weight ratio of 100:24:40. Thoroughly mix the mixture in the ratio of
The adhesive was then passed through a tunnel furnace for adhesive heat treatment at 130'C for 3 minutes until it was slightly sticky to the touch, and then laminated on one side at the same time.
Furthermore, a polyester film with a thickness of 501L-rrL was laminated on the opposite side, passed through a tunnel-shaped hot air oven at a temperature of 110℃ for 15 minutes, and after cutting, a further heat treatment was performed at 150℃ for 10 minutes to increase the thickness. A single-sided copper foil-clad laminate having a length of about 16 mm was obtained and its performance is shown in Table 1.

Example 2 As an adhesive, bisphenol A type epoxy resin (Epicote 828) and isophorone diamine and silane-treated talc (Crystallite CR56002 manufactured by Tatsumori) were used in a weight ratio of 100:24240,
A single-sided copper foil-clad laminate having a thickness of about 166 mm was obtained in the same manner as in Example 1. Its performance is shown in Table 1.

Example 3 As an adhesive, bisphenol A-type epoxy resin (Epicoat 828), inphorondiamine and magnesium oxide (Kyowa Chemical Co., Ltd. Kyomag 30) were used in a weight ratio of 10
Using a ratio of 0:24:40, a laminate having a thickness of about 16 single-sided copper foils was obtained in the same manner as in Example 1.

Its performance is shown in Table 1.

Comparative Example 1 As an adhesive, bisphenol A type epoxy resin (Epicote 828) and inphoronthia 18-mine were used in a weight ratio of 100:24,
A single-sided copper foil-clad laminate having a thickness of about 1.6 mm was obtained in the same manner as in Example 1. Its performance is shown in Table 1.

Comparative Example 2 As adhesives, bisphenol A type epoxy resin (Epicor 1-828) and tetraglygel 1,3-bisaminomethylcyclohexane (ELM43 manufactured by Sumitomo Chemical) were used as adhesives.
4) and inphorondiamine in a weight ratio of 80:20.
:27, and in the same manner as in Example 1, a single-sided steel foil-clad laminate with a thickness of about 1.6 wm was obtained. Its performance is shown in Table 1.

(Left below) 19- 1st 400- (0.15 to 9/cm! 0.05kg/c+n
! 0.14ka/c+s l-2〇- *Testing method was based on JIS C6481.

※※ The sample size is 2 (lOX350), the copper foil residual rate after etching is 34%, and the heat treatment is 150%.
℃×3Qmin was applied and the warpage was measured.

The sample was placed on a surface plate and the average amount of warp measured at the four corners is shown in the table. - When the adhesive layer is turned inside and warped.

When it comes to the outside, it is expressed with shi.

Patent applicant Kanebuchi Chemical Industry Co., Ltd. Representative Patent Attorney Aka Oka 21- 1￥Open 11H5B-85Fi93(7)401-

Claims (9)

[Claims] (1) Multiple paper base layers impregnated with a curable resin that does not substantially generate reaction by-products such as gas or liquid during the curing reaction process, and laminated with an adhesive layer on at least one surface of the paper base layers. In a metal foil-clad laminate for a printed circuit board having a metal foil, the adhesive layer is made of an amine-curing epoxy resin containing 10 to 200 parts by weight of an inorganic filler based on 100 parts by weight of the resin; A paper-based metal foil-clad laminate having a thickness in the range of 5 to 150 ILrrL. (2) The paper base metal foil-clad laminate according to claim 1, wherein the curable resin is a radical polymerization type such as an unsaturated polyester resin, diallyl phthalate resin, or vinyl ester resin. (3) The paper-based metal foil-clad laminate according to claim 1, wherein the curable resin is an addition reaction type such as an epoxy resin. (4) The paper base metal foil-clad laminate according to claim 1, wherein the inorganic filler is a metal oxide such as magnesium oxide or aluminum oxide. (5) The inorganic filler is kaolin, montmorillonite,
The paper base metal foil-clad laminate according to claim 1, which is a clay mineral such as talc or a fired product thereof. (6) The paper base metal foil-clad laminate according to claim 1, wherein the inorganic filler is a silicate mineral such as magnesium silicate or calcium silicate. (7) Claim 1, wherein the inorganic filler is a metal hydroxide such as aluminum hydroxide or magnesium hydroxide.
A paper-based metal foil-clad laminate as described in 2. (8) The paper base metal foil-clad laminate according to claim 1, wherein the inorganic filler is a metal carbonate. (9) The paper-based metal foil-clad laminate according to any one of claims 1 and 4 to 8, wherein the inorganic filler has a Mohs hardness of 5 or less.