JPS5817494B2 - Phenol - Google Patents

Description

[Detailed Description of the Invention] Phenolic resin laminates are relatively inexpensive and have well-balanced performance, so they have been widely used in electronic and electrical parts in recent years. Increasingly, severe requirements are being placed on materials such as punching processability and flame resistance.

One method of improving electrical performance and punching workability is to mix epoxy resin with phenol resin.
In addition, a method of blending halogenated epoxy resin with phenol resin has been proposed in order to impart flame resistance.
When a phenolic resin and an epoxy resin are blended and thermally cured, the reaction between the methylol group or phenolic hydroxyl group of the phenolic resin and the epoxy group is considerably slower than the condensation of methylol groups with each other or the condensation of methylol groups with the phenol nucleus. Therefore, when curing the mixture, it is necessary to take longer pressing time than when using phenol resin alone, which is inefficient in terms of manufacturing.

Moreover, even if the length is longer, the reactions between the methylol groups and between the methylol groups and the phenol nucleus proceed first, making it difficult for the epoxy resin to completely enter into a crosslinked structure, resulting in insufficient properties.

Furthermore, if the epoxy resin is manufactured using the same pressing time as the phenol resin, the reaction of the epoxy resin will be incomplete, resulting in a decrease in electrical performance and a loss of the effect of incorporating the epoxy resin.

The present inventor has investigated various methods of accelerating the curing of a mixture of phenolic resin and epoxy resin and producing a laminate with good electrical performance and other properties even when molded in the same pressing time as phenolic resin. It has been found that the problem can be solved by reacting the epoxy resin with an excess amount of aliphatic amine containing two or more amine groups and then blending it with the phenolic resin.

When an epoxy resin is reacted with an excess aliphatic amine containing two or more amine groups, 1 mole of amine is added to the terminal epoxy group, producing a so-called amine adduct of the epoxy resin.

The primary amine group remaining in this amine adduct is much more reactive with the methylol group of the phenol resin than the epoxy group, and since the amine is adducted to all the epoxy groups in the epoxy resin, the reaction The process proceeds uniformly, and no epoxy resin is left unreacted.

In other words, it has been found that the curing of the phenol resin alone progresses sufficiently in the pressing time, and a laminate with good electrical performance and other properties can be obtained.

The phenolic resin used in the present invention is a phenol resin modified with an alkylphenol obtained by reacting phenol or cresol with formaldehyde in an alkaline state, a phenol resin modified with a drying oil, a phenol resin modified with a xylene resin, or a toluene resin. etc., all of which contain methylol groups in their resins.

An amine adduct obtained by reacting an epoxy resin with an excess of aliphatic amine is obtained by blending and reacting 1 mole or more of amine with respect to 1 epoxy equivalent of the epoxy resin.

If the amount of amine is less than 1 mole, gelation will occur during the reaction.

The aliphatic amines used here include ethylenediamine, diethylenetriamine, triethylenetetramine, etc., which are usually used as curing agents for epoxy resins. Among these, ethylenediamine is used when reacting with epoxy resins to produce amine adducts. is particularly useful because excess diamine can be easily removed by vacuum distillation.

The appropriate blending ratio of amine adduct to 100 parts (weight, same below) of phenolic resin is 10 to 100 parts; if it is less than 10 parts, the effect of adding it will not appear, and if it is more than 100 parts, the methylol in the phenol resin will be mixed. The amine groups in the adduct become excessive with respect to the groups, and the adduct remains unreacted, which actually deteriorates the properties of the laminate.

In addition, a non-reactive plasticizer and a flame retardant can be appropriately used in combination with the blend of the phenol resin and amine adduct of the present invention.

The substrate for the laminate is paper, cloth, glass cloth, etc. which are commonly used for laminates.

This will be explained in detail below using examples.

Example 1 94 parts of phenol, 45 parts of P-tertbutylphenol
parts, 37% formalin 130 parts, 25% ammonia water 4 parts
After refluxing the mixture at 100°C for 2 hours, it was dehydrated under reduced pressure and mixed with methyl alcohol nitriol (1:1).
A phenol varnish with a solid content of 50% was obtained by diluting it with a mixed solvent.

Epoxy resin (bisphenol A type, epoxy equivalent: 45
0 to 500) and 30 parts of ethylenediamine were mixed, and after reacting at room temperature for 5 hours, excess amine was removed by 150 parts.
The mixture was distilled off under reduced pressure at °C, and the resulting adduct was diluted with methyl ethyl ketone to give a solution with a solid content of 50%.

A 10 mils thick cotton linter paper was impregnated with a mixture of 100 parts of the cresol varnish and 40 parts of the amine adduct solution and dried to obtain a laminated material having a resin adhesion resistance of 55%.

8 sheets of the laminated material were stacked and heated at 160°C for 150 minutes.
A laminate with a thickness of 1.6% was obtained by pressing under the conditions of 0.00ml and 0.00ml.

The performance of this laminate is shown in the table.

Example 2 108 parts of cresol and 122 parts of 37% formalin, 25
% ammonia water were mixed, refluxed at 100°C for 2 hours, dehydrated under reduced pressure, and diluted with a mixed solvent of methyl alcohol:dolol (1:1) to obtain a varnish with a solid content of 50%. .

100 parts of epoxy resin (brominated bisphenol A type, epoxy equivalent 380 to 420) and 3 parts of ethylene diamine
After reacting at room temperature for 5 hours, excess amine was distilled off under reduced pressure at 150° C., and the resulting adduct was diluted with methyl ethyl ketone to give a solution with a solid content of 50%.

A 10 mils thick cotton linter paper was impregnated with a mixture of 100 parts of the cresol varnish and 50 parts of the amine adduct solution and dried to obtain a laminated material with a resin coverage of 55%.

The 8 sheets of the laminated material were stacked and heated at 160°C for 50 minutes for 10 minutes.
A laminate with a thickness of 1.6 was obtained by pressing under conditions of 0"7.

The performance of this laminate is shown in the table.

Comparative Example 1 A laminate was obtained under the same conditions as in Example 1 using a varnish prepared by mixing 17 parts of an epoxy resin (bisphenol A type, epoxy equivalent: 450 to 500) to 100 parts of the cresol varnish obtained in Example 1. .

Its performance is shown in the table.

Comparative Example 2 A laminate was prepared under the same conditions as in Example 2 using a varnish prepared by mixing 22 parts of an epoxy resin (brominated bisphenol A type, epoxy equivalent: 380 to 420) to 100 parts of the phenol varnish obtained in Example 2. Obtained.

Its performance is shown in the table. As is clear from the table, the method of the present invention has better electrical performance than the comparative example at the same pressing time.
Excellent handling properties such as punching workability and flame resistance.

This means that curing is significantly accelerated by the method of the present invention,
This shows that a laminate with excellent properties can be obtained in a short pressing time and is very useful industrially.

Claims (1)

[Claims] 1 A phenol resin characterized by impregnating and drying a mixture of phenol resin and adding an amine adduct obtained by reacting excess aliphatic amine and epoxy resin into a base material for laminate products, and then laminating the resin. Method of manufacturing laminates.