JPH039936B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a treatment agent for cellulose substrates for producing unsaturated polyester electrical laminates. The electrical laminate used in the present invention means, for example, a laminate used as a substrate for various electronic components or a metal foil-covered laminate used as a printed circuit board, and has a thickness of about 0.5 to 5 mm. A plate-like object like this. The above-mentioned laminate using unsaturated polyester as a raw material is manufactured by impregnating a cellulose base material with an unsaturated polyester resin, then laminating and curing the impregnated cellulose base material. By pre-impregnating the cellulose base material used in this case with a melamine resin or an epoxy resin, the hygroscopicity of the resulting laminate can be reduced. However, although such an impregnation treatment improves the electrical properties after moisture absorption, the laminate generally becomes brittle, and tends to be susceptible to cracking during punching, for example, and to a decrease in impact strength. The present invention solves the above-mentioned drawbacks by using a specific melamine resin composition for impregnating cellulose substrates. That is, the present invention
An unsaturated polyester electrical laminate cellulose base material comprising a melamine resin obtained by heating and mixing 2 to 5 moles of formaldehyde and 0.1 to 6 moles of alcohol having an ethylenic double bond to 1 mole of melamine. Regarding processing agents. The melamine resin has, for 1 mole of melamine,
It is obtained by heating and mixing 2 to 5 moles of formaldehyde and 0.1 to 6 moles of alcohol having an ethylenic double bond. As the formaldehyde, it is convenient to use formalin, which is commercially available in the form of an aqueous solution. The reaction is usually carried out at a temperature of 40 to 100°C and 15
This can take anywhere from a minute to four hours. It is preferable to maintain the initial pH of the reaction system between 4 and 7 from the viewpoint of ease of reaction control and the properties of the resulting melamine resin. It is preferable to etherify some or all of the methylol groups of the melamine resin with a lower alcohol having 5 or less carbon atoms, since this improves the storage stability of the melamine resin and increases the impact strength of the resulting electrical laminate. The degree of etherification with the lower alcohol is most preferably in the range of 10% to 60% of the methylol group in view of the balance of performance such as punching workability, impact resistance, electrical properties, and warpage properties. The lower alcohol used for etherification is 1 to 20 mol, preferably 8 to 15 mol, per 1 mol of melamine. To perform etherification, a lower alcohol is added simultaneously with melamine, formaldehyde, and an alcohol having an ethylenic double bond, and the initial pH of the reaction system is set to 4 to 7, and the reaction is carried out in a neutral to acidic region, or The lower alcohol can be added during or at the end of the methylolation reaction, or the lower alcohol can be added after reacting melamine, formaldehyde, and an alcohol containing an ethylenic double bond at an alkaline pH of 7 to 10. The etherification reaction may be carried out by making it acidic. Alcohols having ethylenic double bonds as used in the present invention include unsaturated alcohols such as allyl alcohol, as well as partial esters of polyhydric alcohols and α,β-ethylenically unsaturated carboxylic acids. Included are compounds containing at least one alcoholic hydroxyl group and at least one ethylenic double bond. Examples of such partial esters include 2-hydroxyethyl acrylate, 2
-Hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, polyethylene glycol monomethacrylate, polypropylene glycol monomethacrylate, glycerin monomethacrylate, glycerin dimethacrylate, pentaerythritol monoacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate, etc. There is. These compounds may be used alone or in combination of two or more. The use of compounds containing two or more ethylenic double bonds in the molecule, such as glycerin dimethacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate, etc., can improve the punching workability and impact resistance of the laminate. First, it is possible to improve the bending strength and bending rigidity at high temperatures, which were previously thought to be difficult to achieve at the same time, and this is most consistent with the object of the present invention. By adding an alcohol-soluble epoxy compound to the melamine resin, the brittleness of the melamine resin can be improved, and as a result, the punching workability and impact resistance of the laminate can be further improved. Examples of alcohol-soluble epoxy compounds include polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, glycerol diglycidyl ether, trimethylolpropane triglycidyl ether, and the like. A method of using the treatment agent of the present invention is to add a cellulose paper base material such as kraft paper or linter paper, a cellulose cloth such as cotton or rayon, or a nonwoven fabric to a solution or suspension of the melamine resin in a dipping bath or roll coater. Alternatively, it may be impregnated with a spray or the like and then dried. As a solvent, water, alcohol,
Ketones, esters and mixtures thereof may be used. The amount of resin attached to the cellulose base material is 100% of the base material.
The amount per part by weight is preferably 5 to 35 parts by weight, preferably 8 to 27 parts by weight. If the adhesion amount is less than 5 parts by weight, the electrical properties of the resulting laminate after moisture absorption will be greatly reduced, and if it exceeds 35 parts by weight, the punching workability of the laminate will deteriorate. Known methods can be used to produce electrical laminates using cellulose substrates treated with the treatment agent of the present invention. The present inventors have developed a method for continuously manufacturing electrical laminates by molding a base material impregnated with unsaturated polyester resin, which is liquid at room temperature, under no pressure or at a pressure that does not cause excessive flow. 55-4838, Showa 55-126418, Showa 56-98136,
The treatment agent of the present invention can be used to treat cellulose substrates used in these methods. However, it can also be used to treat substrates in other ways, for example in the preparation of prepregs from unsaturated polyester resins and cellulose substrates and the production of laminates by heating and pressing. The present invention will be explained in more detail with reference to Examples below. Example 1 200 g of formalin (formaldehyde 37%, PH
4.3) Add 93.3 g of melamine and 50 g of 2-hydroxyethyl acrylate and stir at 60°C for about 40 minutes to dissolve the melamine. Add 300 g of methanol, stir at 60°C for about 80 minutes, and then cool. 112 g of this solution was dissolved in 65 g of methanol and 35 g of pure water, 285 μm thick kraft paper was immersed in the solution, taken out, squeezed with a roller, and dried at 100° C. for 15 minutes. At this time, the weight increase of paper was 16.8%. On the other hand, an unsaturated polyester synthesized by a conventional method using diethylene glycol, isophthalic acid, and maleic anhydride as raw materials, with a molar ratio of each raw material component of 3:2:1, and an average molecular weight of about 8900.
62 parts of styrene and 38 parts of styrene were mixed with 1 part of cumene hydroperoxide as a curing catalyst and 0.2 part of cobalt naphthenate as an accelerator.
This resin liquid is impregnated into the above treated paper, five sheets are laminated, and the epoxy adhesive is applied at the same time.
Laminated with 35μm electrolytic copper foil and heated to 100℃ as is.
After curing for 45 minutes, a copper-clad laminate with a thickness of 1.6 mm was obtained. The performance is shown in Table 1. Example 2 200 g of formalin (formaldehyde 37%, PH
4.3) Add 93.3g of melamine and 50g of pentaerythritol triacrylate and stir at 70℃ for about 15 minutes to dissolve the melamine. 300g methanol
was added, stirred at 60°C for about 60 minutes, and then cooled. 112 g of this solution was dissolved in 65 g of methanol and 35 g of pure water, 285 μm thick kraft paper was immersed in the solution, taken out, squeezed with a roller, and dried at 100° C. for 15 minutes. At this time, the weight increase of paper was 17.6%. A copper-clad laminate having a thickness of 1.6 mm was made from this treated paper in the same manner as in Example 1. The performance is shown in Table 1. Example 3 200 g of formalin (formaldehyde 37%, PH
4.3), add 93.3g of melamine, 50g of pentaerythritol triacrylate, and 300g of methanol,
Stir at 70℃ for about 150 minutes, then cool. Add 112g of this solution and 1,6-hexanediol diglycidyl ether 8 to 65g of methanol and pure water.
A piece of kraft paper with a thickness of 285 μm was immersed in 35 g of the solution, then taken out, squeezed with a roller, and dried at 100°C for 15 minutes. At this time, the weight increase of paper was 19.2%. Using this treated paper, the thickness was measured in the same manner as in Example 1.
I made a 1.6mm copper clad laminate. The performance is shown in Table 1. Comparative Example 1 32g of methylolmelamine (Nicaresin S-305, Nippon Carbide), 130g of methanol, and 70g of pure water
A piece of kraft paper with a thickness of 285 μm was soaked in the solution, taken out, squeezed with a roller, and dried at 100°C for 15 minutes. At this time, the weight increase of paper was 15.7%. A copper-clad laminate with a thickness of 1.6 mm was made from this treated paper in the same manner as in Example 1. The performance is shown in Table 1. Comparative Example 2 40g of methylated methylolmelamine (Nikaratsuku MX-031, Sanwa Chemical) was added to methanol.
Dissolve 130g in 70g of pure water, soak 285μm thick kraft paper, take out and squeeze with a roller, 100g.
Dry for 15 minutes at °C. At this time, the weight increase of paper is 16.2
It was %. A copper-clad laminate with a thickness of 1.6 mm was made from this treated paper in the same manner as in Example 1. The performance is shown in Table 1.

[Table] According to the law.
Falling ball impact strength is the half-breakage height when a 55-ton iron ball is dropped onto the adhesive surface of a laminate with dimensions 60 mm long and 25 mm wide from which the copper foil has been removed. Bending strength and bending modulus are based on the method of JIS C6481.

Claims (1)

[Claims] 1. An unsaturated product characterized by containing a melamine resin obtained by heating and mixing 2 to 5 moles of formaldehyde and 0.1 to 6 moles of alcohol having an ethylenic double bond to 1 mole of melamine. Polyester electrical laminate cellulose base material treatment agent. 2 An alcohol having an ethylenic double bond is
The processing agent according to claim 1, which is a partial ester of a polyhydric alcohol and an α,β-ethylenically unsaturated carboxylic acid. 3. The treatment agent according to claim 1 or 2, wherein the melamine resin is a melamine resin in which part or all of the methylol groups are etherified with a lower alcohol. 4. The processing agent according to any one of claims 1 to 3, further comprising an alcohol-soluble epoxy compound.