JPH01115922A - Production of flame-retardant resin composition for laminated board - Google Patents

Abstract

PURPOSE:To obtain the above composition giving a laminated board having excellent flame-retardance, heat-resistance and flexibility, by reacting a brominated bisphenol A epoxy resin with triphenyl phosphite and reacting the reaction product with formaldehyde. CONSTITUTION:A objective composition having excellent storage stability is produced by reacting (A) a brominated bisphenol A epoxy resin with (B) triphenyl phosphite and reacting the reaction product with (C) formaldehyde.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides a flame-retardant resin composition for a laminate, which can provide a laminate with excellent flame retardancy, heat resistance, and flexibility, and has excellent storage stability. Concerning the manufacturing method.

BACKGROUND OF THE INVENTION In recent years, in view of the safety of household electrical appliances, there has been an increasing demand for flame retardant printed circuit boards (composed of laminated boards) used therein.

At the same time, among the wide variety of required characteristic items, demands for low-temperature punching workability or non-heating punching workability and heat resistance are becoming stricter year by year due to the requirement for dimensional accuracy.

In contrast, it has been difficult to completely satisfy these requirements with conventional flame retardant resins or flame retardants.

That is, as conventional flame retardants, there are known low molecular weight additive flame retardants that are not reactive and reactive flame retardants that are reactive.

When an additive flame retardant is used, the heat resistance of the resin blended with it is 1. The chemical resistance and electrical properties are reduced, and furthermore, due to the reduction in crosslinking density, the glabella adhesion of the obtained laminate is significantly reduced. In particular, regarding punching workability, peeling between the eyebrows,
Defects such as powder falling during punching and die clogging are more likely to occur.

When used in combination with reactive flame retardants, the above disadvantages are small, but due to the increase in the crosslinking density of the resin when made into a laminate, the softening temperature of the laminate moves to a higher temperature side, and it can be used at low temperatures or without heating. Also, due to its reactivity, the storage stability of the compounded resin and coated base material deteriorates.

A typical example of the former is brominated bisphenol A1
Brominated diphenyl ale i,) IJ phenyl phosphate and its alkyl derivatives, and representative examples of the latter include brominated epoxy resins.

In reality, due to a wide variety of property requirements, additive type flame retardants and reactive type flame retardants are used in combination, taking into account their respective advantages and disadvantages.

In addition, the combination of both, especially halogen (Br is often used in practice) and phosphorus, has advantages from other aspects as well.

In other words, the synergistic effect increases the flame retardant effect when multiple elements with flame retardant effects (halogen, phosphorus nitrogen, boron, etc.) are used in combination than when they are used alone, and as a result, the flame retardant effect increases. Total usage can be reduced. Further, since the additive flame retardant has an excellent plasticizing effect, the flexibility and punching workability of the laminate can be improved by using it in combination.

However, to give an example of the most frequently used composite system of Br and P, both the additive type and the reactive type are in practical use for the Br type, but only the additive type is in practical use for the P type. It has not become a reality.

Therefore, even if it were possible to find a blending ratio that exhibits the optimum flame retardant effect in a composite system of Br and P, the amount used could not be easily increased due to the drawbacks of the additive type flame retardant described above.

Problems to be Solved by the Invention From the above, flame retardant resins and flame retardants that conventionally use P-based compounds have been difficult to adjust the blending ratio to obtain the optimal flame retardant effect due to various constraints on the properties of laminates. The degree of freedom was very narrow, and it could not be said that the combination system with the highest flame retardant effect was necessarily selected.

In view of the above points, the present invention provides a flame-retardant resin for laminates that can be blended and used to obtain a laminate with excellent flame retardancy, heat resistance, and flexibility, and also has excellent storage safety. The purpose is to provide a composition.

Means for Solving the Problems The present invention has been made to achieve the above objects.
This is a method for producing a flame-retardant resin composition for a laminate, which comprises reacting a brominated bisphenol A type epoxy resin and triphenylphosphite (CChHso)sP), and then reacting with formaldehyde.

Action Triphenylphosphite causes an ester reaction with the hydroxyl group of the brominated bisphenol A epoxy resin, and chemically integrates into the molecule of the brominated bisphenol A epoxy resin while releasing phenol (formula (1)
).

-OH 10◇o-p (o◇)yoH → -o-p (o◇)8+0 ・・・・・・・・・(
1) Since triphenylphosphite is trifunctional, it can itself become the center of crosslink formation. This reaction results in
Triphenylphosphite is involved in the crosslinking of brominated bisphenol A epoxy resin and is incorporated into its skeleton, so it can be used without exposing the drawbacks of phosphate esters, which are conventional additive flame retardants. It is possible to have a higher phosphorus content than before, and the amount used can be increased to the point where the synergistic effect of Br and P on flame retardancy is most effective.

As shown in formula (1), when triphenylphosphite undergoes an ester reaction with 1 mole of hydroxyl group, 1 mole of phenol is produced. The generated phenol has the effect of slightly lowering the crosslink density by reacting with the epoxy group, thereby improving flexibility. However, if this continues, it is inevitable that unreacted phenol will remain.

Therefore, the present invention is characterized in that formaldehyde is further added to the reaction product of the brominated bisphenol A type epoxy resin and triphenyl phosphite in order to methylolize the produced phenol and make it reactive.

As described above, the flame-retardant resin according to the present invention has a higher phosphorus content than before without deteriorating properties by incorporating phosphorus atoms into the crosslinked structure of the brominated bisphenol A epoxy resin. In addition to increasing the flame retardant effect per unit amount used, a part of the generated phenol reacts with epoxy groups, thereby improving flexibility. Furthermore, by converting free phenol into methylol, all components in the system can be involved in the reaction with the phenolic resin blended as a flame retardant.

EXAMPLE In carrying out the present invention, brominated bisphenol A
Regarding the usage ratio of type epoxy resin and triphenylphosphite, in order to avoid unreacted triphenylphosphite remaining, [hydroxyl group equivalent of brominated bisphenol A type epoxy resin] ≧ [molecule XI of triphenylphosphite] /3). The catalysts used at this time are benzyldimethylamine, 2-(dimethylaminomethyl), in order to prevent the brominated bisphenol A type epoxy resin from becoming polymeric and three-dimensional, and from the viewpoint of heat resistance. phenol,
Aromatic tertiary amines such as 2.4.6-tris(dimethylaminomethyl)phenol are preferred. The amount added is
0.5 to 1,100 per solid total weight of brominated bisphenol A epoxy resin and triphenylphosphite
5 parts by weight is desirable.

Further, the amount of formaldehyde used is preferably in the range of [number of moles of triphenylphosphite×3]≧[number of moles of formaldehyde]≧[number of moles of triphenylphosphite]. If used in excess, formaldehyde will remain; if used in small quantities, phenol will remain. When the flame retardant resin of the present invention is blended and used, it can be used alone or in combination with an additive type flame retardant such as triphenyl phosphate or brominated diphenyl ether with a relatively low Mk. However, in either case, the total amount of flame retardant resin and flame retardant used can be reduced.

Next, one embodiment of the present invention will be described.

Example 1 Bromine content 48%, epoxy equivalent 400, hydroxyl equivalent 1
3700 g of a 60% toluene solution of 12200 brominated bisphenol type A epoxy resin, 103 g of triphenylphosphite, and 23 g of benzyldimethylamine.
g was put into a Mitsuro flask and reacted for 4 hours at ao''c.Furthermore, 23g of 86% rose formaldehyde was added and the reaction was continued at 80°C for 2 hours (Reactant 1).

Separately, a tung oil-modified phenol resin was obtained as follows.

720 g of tung oil and 580 m-cresol in a Mitsuro flask
g, 0.74 g of para-toluenesulfonic acid was added, and after reacting at 80°C for 1 hour, 500 g of phenol18
Add 450 g of 6% paraformaldehyde and 35 g of 25% aqueous ammonia, proceed with the reaction at 80°C, and when the reaction product hardens on a 160°C hot plate for 6 minutes, dehydrate and concentrate. Methanol was then added to adjust the resin content to 50%.

The solid content ratio of this tung oil-modified phenolic resin and the reactant 1 is [tung oil-modified phenolic resin]/[reactant 1].
The mixture was mixed and dissolved in a ratio of -80/20, coated on an 11 mils kraft paper substrate and dried to give a resin adhesion of 1tso%.

A 35μ thick copper foil coated with an adhesive and 8 sheets of the above-mentioned coating method paper base material were combined and laminated, and heated and pressed to obtain a single-sided copper-clad laminate with a thickness of 1.6 mm.

Example 2 3700 g of a 60% toluene solution of a brominated bisphenol A epoxy resin with a bromine content of 48%, an epoxy equivalent of 400, and a hydroxyl equivalent of 2200, 90 g of triphenylphosphite, and 30 g of 2-(dimethylaminomethyl)phenol. Pour into the Mitsuro flask and heat at 80°.
The reaction was carried out at C for 4 hours. Further, 25 g of 86% paraformaldate was added, and the reaction was continued at 80°C for 2 hours (Reactant 2).

Using Reactant 2 and using the same blending amount and method as in Example 1, a single-sided copper-clad phenolic resin laminate having a thickness of 1.6 cm was obtained.

Comparative Example 1 The tung oil-modified phenolic resin used in Example 1 and a 60% toluene solution of brominated bisphenol A diglycidyl ether with a bromine content of 48% and 11,400 epoxy weight were mixed in terms of solid content ratio [tung oil-modified phenolic resin]/[ Brominated bisphenol A diglycidyl ether) -80/
A single-sided copper-clad laminate having a thickness of 1.6111 ffl was obtained using the same method as in Example 1.

Comparative Example 2) Tung oil modified phenolic resin used in Example 1 and Comparative Example 1
The solid content ratio of brominated bisphenol A diglycidyl ether and triphenyl phosphate used in [tung oil modified phenolic resin]/[brominated bisphenol A
diglycidyl ether)/()riphenyl phosphate] - mixed and dissolved in a ratio of 60/30/10, and this was dissolved in 11
The mixture was coated on Mils kraft paper and dried, followed by the same method as in Example 1 to obtain a single-sided steel-clad laminate having a thickness of 1.6 am.

Table 1 shows the test results of the laminates obtained in Examples and Comparative Examples.

As is clear from the test results that exceed the effects of the invention, the present invention has improved N
In addition to the above-mentioned effects, the laminate has improved combustion efficiency, flexibility, and heat resistance, and because the method of the present invention contains almost no unreacted plasticizer-like components in the system. Chemical resistance can also be significantly improved.

Claims (1)

[Claims] A method for producing a flame-retardant resin composition for a laminate, comprising further reacting formaldehyde with a reaction product obtained by reacting a plum-formed bisphenol A-type epoxy resin and triphenylphosphite.