JPH06134937A - Manufacture of flame retardant laminated plate - Google Patents

Abstract

PURPOSE:To obtain excellent electric characteristics, punching processability and silver migration resistance by using mixture of amino resin or phenol resin with aqueous soluble compound represented by a specific general formula as initial impregnating resin and then laminating to form a laminating material obtained by coating and impregnating it with thermosetting resin on a sheet base material. CONSTITUTION:Mixture of amino resin or phenol resin with aqueous soluble compound represented by a formula I (R1: -CH3 or -C2H5, R2: -C2H4OH or -C3H6OH) as initial impregnating resin is used on a sheet base material. The compound of the formula I contains high phosphorus content of flame retardant component, has excellent affinity with cellulose fibrous base material, excellent compatibility with the amino resin or phenol resin to used to treat the base material. When it is mixed with initial impregnating coating resin, its impregnation and flexibility are improved. Then, a laminating material is obtained by using thermosetting resin for coating and impregnating at a second stage. The obtained laminated material is laminated to obtain a thermosetting resin laminated plate.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a flame-retardant paper base thermosetting resin which has excellent electrical characteristics and processability and is less likely to cause a silver migration phenomenon (hereinafter referred to as "excellent silver migration resistance"). The present invention relates to a method for manufacturing a laminated board.

[0002]

2. Description of the Related Art Conventionally, a printed circuit wiring board paper base material phenol resin laminated board is obtained by impregnating and drying a phenol resin varnish on kraft paper or linter paper, laminating the impregnated paper, and adding copper foil to one or both sides. Is molded and manufactured.

However, the paper-based phenolic resin laminate thus obtained has a silver content after a lapse of a predetermined time when an electric field is applied between the silver electrodes formed on the surface of the laminate under temperature and humidity conditions. It is well known that the transition phenomenon occurs.

Many attempts have been made to electrochemically analyze the migration phenomenon of silver, and it has been pointed out that the difference in the migration phenomenon of silver depending on the insulating material is paper-based phenolic resin laminates. With the base epoxy resin laminate,
It is positioned as the one in which the migration phenomenon of silver is extremely likely to occur.

However, as the density of printed circuit wiring boards has increased in recent years, securing reliability is an important issue. However, this phenomenon of silver migration has a factor that can be a fatal defect for printed circuit wiring boards. In the production stage of circuit wiring boards, various treatments that can suppress the migration phenomenon of silver have been tried and are actually carried out, but the part that strongly depends on the essential characteristics of the laminated board is strong and the silver migration resistance is high. What is needed is a paper-based phenolic resin laminate having excellent properties. The present inventor has conducted a detailed study on migration of silver on the surface of a paper-based phenolic resin laminate, and has found that impregnating ability of a phenolic resin composition into a paper substrate has a large factor. There is.

Double coating is well known as a means for improving the impregnating property of paper.
In terms of the properties of the obtained copper-clad laminate, mechanical properties are deteriorated, which is not preferable.

On the other hand, there is an increasing demand for flame retardancy for laminated plates used for insulating materials due to the safety-oriented climate. Conventionally, there are cases where an additive type flame retardant in which a halogen or phosphorus compound is added to a resin is used for flame retardation of a laminated board, and a case where a reaction type flame retardant chemically bonded to a resin is used, Each has advantages and disadvantages. In the former case, the flame retardant remains unreacted in the product, resulting in deterioration of properties such as heat resistance and solvent resistance. Therefore, a reactive flame retardant is preferred in order not to cause deterioration of properties. On the other hand, as a reactive flame retardant, an epoxy compound having a halogen-substituted aryl group has hitherto been often used, but when used in a large amount, flexibility is lowered and punching workability at low temperature is lowered.

[0008]

SUMMARY OF THE INVENTION The present invention is intended to solve the above problems, and has the following characteristics:
The present invention relates to a method for producing a flame-retardant laminate excellent in silver migration resistance without deteriorating processability and other properties.

[0009]

The first aspect of the present invention is the production of a thermosetting resin laminate by laminating a laminated material obtained by coating and impregnating a paper base material with a phenol resin in a two-step process. The following general formula [I]

[0010]

[Chemical 2]

A flame-retardant laminate characterized by using a water-soluble compound represented by the formula (1) and an amino resin or a phenol resin mixed therein, and then using a laminate material obtained by coating and impregnating a thermosetting resin. Is a manufacturing method.

The paper base material in the present invention contains cellulose fibers as a main component, and kraft paper, linter paper, mixed paper or glass fiber mixed paper is used. The resin used for treating the paper base material of the present invention is an amino resin, a phenol resin or a mixture thereof. The amino resin referred to here is melamine resin, guanamine resin, or the like. These are initial condensation products of melamine, guanamine and aldehydes such as formaldehyde, and may be those in which some or all of their methylol groups are etherified with a lower alcohol such as methanol or butanol. The phenol resin is an initial condensate of phenol, cresol, xylenol, resorcin and the like with aldehydes such as formaldehyde, and may be an oil-modified phenol resin.

The compound represented by the formula [I] is a water-soluble compound having a high content of phosphorus, which is a flame retardant component, and flexibility, and can be used in a linter paper, a kraft paper or the like used as a base material for a laminated board. Good affinity with cellulose fiber base material.
Further, it is also excellent in compatibility with amino resins or phenol resins used for treating paper base materials, and when blended with the resin for the first impregnation coating, it is possible to improve the impregnation property and flexibility to a high degree.

The compounding amount of the compound [I] is not particularly limited to the following range, but is preferably 5 to 50 parts by weight based on 100 parts by weight of the solid content of the amino resin or the phenol resin. . If the amount is less than 5 parts by weight, the effect of improving punching property and flame retardancy, which are the features of the present invention, will not be exhibited. descend.

The amount of the resin compounded with the compound [I] attached to the paper base material is 5 to 3 with respect to 100 parts by weight of the paper base material.
0 parts by weight is preferred. If it is less than 5 parts by weight, the moisture resistance is lowered, and if it exceeds 30 parts by weight, the laminated plate becomes hard and brittle.

Examples of the thermosetting resin used for the second impregnation include phenol resin, epoxy resin, unsaturated polyester resin, thermosetting acrylic resin, etc., but from the viewpoint of flame retardancy, punchability, etc. A tung oil-modified phenolic resin containing a modified epoxy resin or the like is preferable.

[0017]

EXAMPLES The present invention will be described below with reference to examples.

[Synthesis Example 1] Phenol 1000 g, 37
% Formaldehyde aqueous solution 1300 g and triethylamine 25 g were reacted at 60 ° C. for 8 hours, and then water was removed under reduced pressure. Resin varnish [A] with a resin content of 10%, diluted with a solvent of water / methanol = 1/1.
Was manufactured.

[Synthesis Example 2] Tung oil 800 g, metacresol 800 g, paratertiary butylphenol 3
00 g and paratoluenesulfonic acid 2 g were reacted at 95 ° C. for 1 hour, and then 25% ammonia water 8 g and paraform 150 g were added and reacted at 85 ° C. for 2 hours. To this, 250 g of commercial flame retardant tetrabromobisphenol A diglycidyl ether, triphenyl phosphate 1
After adding 50 g, a solvent of methanol / toluene = 1/1 was added to obtain a thermosetting resin varnish [B] having a resin content of 50%.

[Example] Kraft paper of 135 g / m ² was mixed with a compound [II] having the following structural formula.

[0021]

[Chemical 3]

Was treated with varnish [C] added to resin varnish [A] to obtain various treated papers shown in Table 1.

Eight prepregs impregnated with the thermosetting resin varnish [B] were stacked on the treated paper and heat-molded to form 1.5.
A mm-thick laminate was obtained. A test pattern as shown in FIG. 1 was screen-printed on this laminated plate using a conductive silver paint.

In FIG. 1, 1 and 2 are circuits formed of conductive silver paint, and the distance between the circuits is 0.7.
mm. Using this sample, silver migration resistance was measured.

The method is as follows. Temperature 60 ℃,
Put it in a thermo-hygrostat with a humidity of 90% and put a direct current of 30 between the opposing circuits.
The voltage of V is continuously applied and left for 1000 hours. The insulation resistance between the circuits of this sample is measured, and the appearance of the silver migration phenomenon from the appearance is observed.

The results are shown in Table 1. Table 2 shows various characteristics of the obtained laminated plate.

The test method is water absorption, insulation resistance is JIS
Performed according to C6481 and the punchability is ASTM D-
617.

[0028]

[Table 1]

[0029]

[Table 2]

[0030]

As is clear from the above examples, the flame-retardant laminate obtained by the method of the present invention has excellent electrical characteristics, punching workability and silver migration resistance.

[Brief description of drawings]

FIG. 1 is a circuit pattern for a silver migration test.

[Explanation of symbols]

 1, 2 silver paint circuit

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[Procedure amendment]

[Submission date] December 10, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Delete

Claims (1)

[Claims] 1. In the production of a thermosetting resin laminate in which a paper base material is coated and impregnated with a phenol resin in a two-step system and dried to laminate-form a laminate material, the following resin is used as the first impregnation resin. General formula [I] A method for producing a flame-retardant laminate, which comprises using a mixture of a water-soluble compound with an amino resin or a phenol resin, and then using a laminate material obtained by coating and impregnating a thermosetting resin. .