JPS6239635A - Production of phenolic resin laminated board - Google Patents

Abstract

PURPOSE:To produce a laminated board having improved punchability, by impregnating a cellulosic base material with a priming resin modified with a specific compound, impregnating the resultant with a facing phenolic resin to give prepreg and laminating and curing a given number of prepreg. CONSTITUTION:A priming resin obtained by cocondensing one or more selected from aliphatic amines, aliphatic amides, preferably (meth)acrylamide and oligomers or polymers thereof with a phenol together with formaldehyde to form a cocondensate or adding a phenolic resin thereto is previously impregnated into a cellulosic base material and dried. A facing phenolic resin, preferably vegetable-modified resol type phenolic resin is then impregnated thereinto to form prepreg. Plural sheets of the prepreg are then placed on top of each other and copper foils are superposed thereon. Alternatively, the sheets of prepreg are laminated without the copper foils and cured to produce the aimed laminated board.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing cellulose-based phenolic resin laminates (including copper-clad laminates) that have particularly excellent punching workability.

[Conventional technology]

Phenol resin laminates are widely used mainly as circuit boards for consumer electronic devices, and holes are punched using a power press. Recently, as electronic components have become more dense and smaller, the substrates on which these electronic components are mounted are also required to have small holes and high-density punching.

As the diameter of the punched holes becomes smaller and the density increases, defects such as peeling within the substrate and cracks on the surface of the substrate become more likely to occur, creating problems in terms of electrical connection reliability of the substrate. In order to deal with these problems, methods of modifying the phenolic resin with vegetable oil or the like or plasticizing the resin with a plasticizer have been used so far. However, in phenolic resin laminates, the cellulose base material is pretreated with unmodified phenolic resin or melamine-modified phenolic resin in order to maintain electrical properties such as insulation resistance, and sometimes to maintain flame resistance. In order to carry out these preliminary treatments, methods such as modifying or plasticizing the top coating resin alone have not been able to achieve a satisfactory effect in improving the punching processability.

[Means for solving problems]

The present invention provides a phenolic resin laminate with a cellulose base material that has excellent punching workability by modifying the undercoating resin. The present invention provides an undercoat resin consisting of a co-condensate or a mixture of one or more selected from aliphatic amines, aliphatic amides, and oligomers or polymers thereof and a phenol resin, which is applied to a cellulose base material in advance. After being impregnated and dried, it is impregnated with a phenolic resin for top coating to form a prepreg, which is stacked in multiple layers, with or without copper foil, and heated and pressed to harden the resin. A laminate is obtained.

Aliphatic amines used in the present invention include propylamine, butylamine, octylamine, nonylamine,
There are linear alkylamines such as allylamine and alicyclic amines such as cyclohexylamine and cyclopentylamine. As the aliphatic amide, acid amides such as acetamide, valeramide, acrylamide, and methacrylamide are used. Further, as the amine and amide oligomers and polymers, furylamine, acrylamide and methacrylamide oligomers and polymers are used. However, for the present invention, acrylamide, methacrylamide, and their oligomers and polymers are advantageous in terms of performance and economy.

The undercoat resin of the present invention is prepared by cocondensing the aliphatic amine, aliphatic amide, or their oligomers, polymers, and phenols together with formaldehyde to form a cocondensate, or by adding and mixing a phenol resin. The reaction end point of the undercoating resin is set such that the gel time is 2 minutes 30 seconds to 3 minutes 30 seconds from the viewpoint of the curing time and storage stability of the varnish.

The amount of the aliphatic amine, amide, oligomer or polymer thereof to be used is preferably 5 to 50 parts by weight per 100 parts by weight of the phenol used. If the amount used is less than 5 parts by weight, the effect of improving punching workability will be small, and if it exceeds 50 parts by weight, there will be problems with the storage stability of the varnish and the compatibility with the resin. When an aliphatic amine or amide polymer is used, its molecular weight is desirably 500.000 or less in terms of number average molecular weight. If the molecular weight is larger than this, it becomes difficult to impregnate the cellulose base material with the aliphatic amine or amide, resulting in a decrease in electrical properties and moisture resistance.

Next, a cellulose base material is impregnated with the obtained undercoat resin. The cellulose base material is generally kraft paper, linter paper, etc., and is not particularly limited as long as the desired properties can be obtained. Also, the amount of undercoat resin used is 5 to 2
0% by weight is desirable.

If it is less than 5% by weight, the electrical properties and moisture resistance will be poor, and if it exceeds 20% by weight, the effectiveness of the top coat resin will be reduced.

After drying, it is impregnated with a phenolic resin for top coating.

The phenolic resin for the top coating is not particularly limited, but in order to obtain excellent punching workability, a vegetable oil-modified phenolic resin or a phenolic resin plasticized with a plasticizer is desirable. The adhesion resin content is preferably 50 to 60% by weight, including the amount of undercoat, from the viewpoints of workability, economy, and performance.

This is dried to form a prepreg.

A laminate is obtained by stacking a predetermined number of prepregs, stacking them with or without copper foil, and molding them under heat and pressure. The molding conditions are not particularly limited.

The laminate manufactured by the above method has excellent punching workability and can be used as a circuit board for consumer electronic equipment.

〔Example〕

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

Example 1 Synthesis of undercoating varnish A 300 g of Fe/-/l/, 500 g of a 37% formalin aqueous solution, and 25 g of a 30% trimethylamine aqueous solution were mixed and reacted at 70°C for 5 hours. The gel time after completion of the reaction was 2 minutes and 50 seconds on a 160°C hot plate. 45 g of dicyclohexylamine was added to this reaction solution, and a mixed solvent of water and methanol (1:1) was further added to adjust the resin content of the system to 12% by weight, thereby obtaining varnish A for undercoating.

Synthesis of top coating varnish 1500 g of metacresol, 1000 g of tung oil, 1 g of paratoluenesulfone M' were mixed and reacted at 100° C. for 1 hour. Next, 360g of phenol was added to this reaction solution.
and 730 g, l of 80% rose formaldehyde.
- After adding 57 g of 30% aqueous solution of remethylamine, 8
The reaction was continued for 6 hours at 0°C. The gel time after completion of the reaction was 2 minutes and 30 seconds on a 160°C hot plate. A mixed solvent of toluene-methanol (1:1) was added to this reaction solution so that the resin content of the system was 50% by weight to prepare a top coat varnish.

Example 2 Synthetic phenol 300g for undercoating varnish B, 37% formalin water? Yong? night
500g, trimethylamic acid 30% water? 25 g of the solution and 30 g of polyacrylamide having a number average molecular weight of 5000 were mixed and reacted at 70°C for 5 hours. The gel time after completion of the reaction was 2 minutes and 40 seconds on a 160°C hot plate. A mixed solvent of water and methanol (1, 1) was added to this reaction solution, and the resin content of the system was adjusted to 12% by weight to obtain varnish B for undercoating.

Comparative Example Phenol 300g, 37% formalin water solution 50%
0g and 25g of a 30% trimethylamine aqueous solution were mixed and reacted at 70°C for 5 hours.The gel time after the reaction was 2 minutes and 40 seconds on a 160°C hot plate. A mixed solvent of water and methanol (1:1) was added to this reaction solution, and the resin content of the system was adjusted to 12% by weight to obtain a comparative undercoat varnish.

Resin content adjusted in Example 1.2 and Comparative Example above: 12% by weight
Cotton linter paper was impregnated with each of the undercoat varnishes and dried, and then the topcoat varnish synthesized in Example 1 was impregnated into the pretreated Cotton linter paper and dried to prepare prepregs. . A predetermined number of sheets of the prepreg were stacked and heated under a pressure of 100 kg/crA.
Heat molding was performed at 70° C. for 100 minutes to obtain a laminate. The properties of the laminate were measured according to JIS-C-6481, and the evaluation of punching workability was measured according to ASTM-D617.

The results are shown in Table 1.

Table 1 [Effects of the Invention] As is clear from Table 1, the laminate obtained by the present invention has a low-temperature punching processability of 1/1, which is a great effect. Furthermore, no deterioration in other laminate properties was observed due to the use of aliphatic amines, amides, and their oligomers and polymers, and its industrial value is extremely large.

Claims (1)

[Claims] 1. An undercoat resin comprising a cellulose base material, a co-condensate or a mixture of one or more selected from aliphatic amines, aliphatic amides, oligomers or polymers thereof, and a phenolic resin. A method for manufacturing a phenolic resin laminate, which comprises pre-impregnating the laminate with a phenol resin for topcoating, forming a prepreg, laminating a predetermined number of sheets, and curing the phenol resin laminate. 2. The method for producing a phenolic resin laminate according to claim 1, wherein the aliphatic amide is acrylamide or methacrylamide. 3. The method for producing a phenolic resin laminate according to claim 1 or 2, wherein the phenolic resin for top coating is a vegetable modified resol type phenolic resin.