JPH044945B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for manufacturing a substrate for a flexible printed wiring board. (Prior Art) In recent years, with the diversification of electronic devices, flexible printed wiring boards that are lightweight and can be mounted in a vertically functional manner have come into widespread use. As adhesives for this purpose, compositions made of acrylonitrile butadiene rubber and alkylphenol resins, or compositions made by appropriately blending epoxy resins, etc.
36861, Special Publication Showa 57-1158, etc.). (Problems to be Solved by the Invention) However, in order to apply it to electronic devices that have become increasingly sophisticated in recent years, it has become necessary to further improve heat resistance. For example, when polyimide is used as an insulating substrate, it has excellent heat resistance, but because it absorbs moisture, it has the disadvantage that the soldering heat resistance when moisture is absorbed is significantly reduced. Therefore, the adhesive requires strong adhesive strength with the base film and high heat resistance of the adhesive itself. This lack of heat resistance is due to insufficient crosslinking between the acrylonitrile butadiene rubber and the phenol resin, and it is thought that it is necessary to ensure crosslinking of the rubber. The present invention has been made to solve the above-mentioned conventional problems, and provides a method for manufacturing a substrate for a flexible printed wiring board that has particularly excellent solder heat resistance and solder heat resistance when moisture is absorbed. be. (Means for Solving the Problems) The present invention involves the addition reaction of aldehyde to alkylphenols, and the resulting addition reaction resin.
Use of an adhesive containing as essential components a modified resin obtained by adding and co-condensing phenols and/or amines that are more reactive with aldehydes than the alkyl phenols, and acrylonitrile butadiene rubber. Features. As the alkylphenols, P-substituted alkylphenols, P-phenylphenols and/or P-kyumylphenols are used. Examples of the P-substituted alkylphenols include amylphenol, butylphenol, Sec-butylphenol, and octylphenol. P
- phenylphenol or P-kyumylphenol is 0.2 to P-substituted alkylphenol
~0.8 mol is used, and 1.3 mol or more of aldehyde (formaldehyde, acetaldehyde, etc.) is added to 1 mol of the total amount of phenol in the presence of a basic catalyst. In the addition reaction product thus obtained, preferably phenols or amines having higher reactivity with aldehydes than the alkyl phenol are mixed into the product.
Add 10% by weight and condense. Phenols that are highly reactive with aldehydes include resorcinol,
Catechol, metacresol, phenol, etc. can be used, and as amines, melamine, benzoguanamine, acetoguanamine, tetramethylenehexamine, urea, etc. can be used. The reason why the amount added is preferably limited to 0.1 to 10% by weight is that 0.1% by weight
This is because if it is less than 10% by weight, the adhesive will not be able to fully exhibit the heat resistance that is the objective of the present invention, and if it exceeds 10% by weight, the compatibility with the acrylonitrile butadiene rubber used as the adhesive will decrease. Acrylonitrile butadiene rubber is a copolymer of acrylonitrile and butadiene, or one or more copolymerizable monomers such as acrylic acid. Although the acrylonitrile content is not limited, commercially available products preferably have an acrylonitrile content of 19% or more. As for the adhesive, the composition ratio of the above-mentioned modified resin and acrylonitrile butadiene rubber is 50/50/solid weight ratio.
Can be used in the range of 50 to 7/93. If the composition ratio of the modified resin and acrylonitrile butadiene rubber is more than 50%, the adhesive strength will be insufficient, and if it is less than 7%, the crosslinking of the rubber will be insufficient, and other thermosetting This is because even if a synthetic resin is blended, the soldering heat resistance will decrease. Although the above is the basic composition, flame retardant epoxy resin, filler, etc. are effective for flame retardancy, chemical resistance, and adjustment of adhesive flow, and can be used as appropriate. The above components are kneaded and mixed in an organic solvent, and one or more organic solvents such as methyl ethyl ketone, acetone, toluene, methyl isobutyl ketone, xylene, and ethyl acetate can be used. The method of manufacturing a substrate for a flexible printed wiring board using this adhesive is to apply it to a base film or metal foil so that the thickness after drying is generally 30 ± 15 μm, and then apply it to a substrate film or metal foil for 5 to 30 minutes at 120 ± 30 °C. Dry for a minute,
Bring the adhesive to a semi-cured state. Next, the metal foil is laminated on one or both sides of the base film and bonded at 120 to 220° C. using a press or a heat-pressing device such as a laminator. After bonding, it can be further heated and cured if necessary. Example 1 P-tertiary butylphenol 75g (0.5
mol), P-phenylphenol 85g (0.5 mol)
After a heating reaction of 162 g (2 mol) of formaldehyde and 1 g (0.025 mol) of sodium hydroxide at 98 to 100°C for 3 hours, 1.5 g (0.1 g) of hydrochloric acid was added and neutralized and washed with water. To this was added 8 g of resorcinol ( A modified phenolic resin with a softening point of 120°C was obtained by co-condensation of 5% by weight of the phenolic resin.The adhesive was prepared by dissolving 100 parts of the above modified resin and 200 parts of acrylonitrile butadiene rubber (acrylonitrile 33%) in methyl ethyl ketone. A solution with a concentration of approximately 20% was prepared.This was applied to a polyimide film with a thickness of approximately 25 μm.
After coating 25μm and drying at 120℃ for 10 minutes, the thickness
A flexible copper-clad board was created by laminating it with a 35 μm rolled copper foil and heat-pressing it at 170° C. at 50 kg/cm ² for 60 minutes. The main performance of this product is shown in Table 1. Comparative Example 1 150 g of P-tert-butylphenol, 162 g (2 mol) of formaldehyde, and 1 g (0.025 mol) of sodium hydroxide were reacted by heating at 98 to 100°C for 3 hours, and then 10.5 g (0.1 mol) of hydrochloric acid was added to the mixture. Washed with Japanese water. Remove water while heating to 130
The reaction was carried out at ℃ to obtain a phenolic resin with a softening point of 110℃. A flexible copper-clad board was prepared in the same manner as in Example 1, except that 100 parts of the above phenolic resin was used as the adhesive. The main performances of this product are shown in Table 1. Example 2 P-tertiary amylphenol 82g (0.5
mol), P-phenylphenol 85g (0.5 mol)
75 g (2 mol) of paraformaldehyde, 4 g (0.1 mol) of sodium hydroxide, and 100 g of toluene were added, and the mixture was reacted at 90°C for about 2 hours.
It was neutralized by adding 15% acetic acid and washed with water. Thereafter, the reaction was carried out at 120°C while removing the solvent, and 1.6 g of resorcin (1% based on the weight of phenol) was co-condensed to obtain a modified phenolic resin having a softening point of 105°C. As an adhesive, 130 parts of the above modified resin, acrylonitrile butadiene rubber (acrylonitrile 33 parts)
%), 520 parts, epoxy resin and its curing agent, bisphenol type epoxy resin
A methyl ethyl ketone solution with a concentration of 20% was prepared from a composition consisting of 50 parts of Epicoat 1001 (trade name, manufactured by Co., Ltd.) and 10 parts of monoethylamine boron trifluoride complex. Next, using a reverse roll coater, coat the polyimide film with a thickness of 25 μm.
Apply to a thickness of 20 μm and continue to heat at 120℃.
After drying for 5 minutes in a drying oven, it was laminated with a rolled copper foil having a thickness of 35 μm, passed between heated rolls at 180° C., laminated, and wound up. this thing
Post-heating was carried out for an additional 4 hours at 140°C. The main performances of this product are shown in Table 1. Comparative Example 2 Example 2 except that only P-tertiary aminophenol was used as the phenol component in Example 2, and resorcin co-condensation was not performed.
In the same manner as above, adhesive was prepared and a flexible copper-clad board was made. The main performances of this product are shown in Table 1. Example 3 P-tert-butylphenol 120g (0.8
mol), P-kyumylphenol 42.4g (0.2 mol), paraformaldehyde 68.5g (1.8 mol),
12.5 g (0.04 mol) of barium hydroxide and 70 g of benzene were mixed and reacted at 75 to 80°C for 5 hours. After that, 21g of hydrochloric acid was added to neutralize, washed with water, and 48.6g of resorcin was added to the reaction solution to dehydrate and remove the solvent.
The reaction was carried out at 120-130°C to obtain a modified phenolic resin with a softening point of 113°C. As adhesive, 70 parts of the above modified resin, acrylonitrile butadiene rubber (acrylonitrile 33%)
580 parts, epoxy resin and novolac type epoxy as a curing agent (trade name BREN-S, manufactured by Nippon Kayaku Co., Ltd.)
190 parts, poly P-vinylphenol (Maruzen Oil Co., Ltd.)
A composition was prepared consisting of 160 parts of Resin MB (trade name) and 60 parts of antimony trioxide as a filler. Next, a flexible copper-clad board was prepared in the same manner as in Example 1. The main performances of this product are shown in Table 1. Example 4 75 g (0.5 mol) of P-tertiarybutylphenol and 85 g (0.5 mol) of P-phenylphenol were mixed with 162 g (2 mol) of formaldehyde and 1 g (0.025 mol) of sodium hydroxide at 98 to 100°C.
After a heating reaction for a period of time, 10.5 g (0.1 mol) of hydrochloric acid was added to neutralize and wash with water. This product was co-condensed with 8 g of melamine (5% by weight based on the phenol resin) to obtain a modified resin. Next, a flexible copper-clad board was created in the same manner as in Example 1. The main properties of this product are shown in Table 1.

[Table] (Effects of the invention) The flexible printed wiring board of the present invention has heat resistance,
It has particularly excellent soldering heat resistance and moisture absorption soldering heat resistance.

Claims (1)

[Scope of Claims] 1A Addition reaction of aldehyde to alkylphenols and to the resulting addition reaction resin,
Through an adhesive containing as essential components a modified resin obtained by adding and co-condensing phenols and/or amines that are more reactive with aldehydes than the alkyl phenols, and B acrylonitrile butadiene rubber. , a method for manufacturing a substrate for a flexible printed wiring board, which comprises superimposing a film-like substrate and a metal foil and bonding them under heat and pressure. 2. The method for producing a substrate for a flexible printed wiring board according to claim 1, wherein the composition ratio (weight) of the modified resin and acrylonitrile butadiene rubber is in the range of 50/50 to 7/93. 3. The method for producing a substrate for a flexible printed wiring board according to claim 1 or 2, wherein the alkylphenols are P-substituted alkylphenol, P-phenylphenol, and/or P-quinylphenol.