JPH0379635A - Method for impregnating fibers with liquid phenolic resin - Google Patents

Abstract

PURPOSE:To homogeneously and sufficiently impregnate the interior of a fiber bundle with a resin and enhance strength of the subject fiber by dipping stranded reinforcing fiber in diluted liquid phenolic resin stock solution, drying the dipped fiber, evaporating and removing the diluting solvent. CONSTITUTION:For example, ethyl alcohol as a solvent is added to a liquid phenolic resin having 10P viscosity to provide a diluted stock solution having 5P viscosity. Stranded glass fiber is then dipped in the aforementioned diluted stock solution to permeate the solution. The above-mentioned fiber is subsequently dried to evaporate the diluting solvent and afford the objective fiber.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a method for impregnating fibers with liquid phenolic resin.

[Conventional technology]

Conventionally, phenolic resins have relatively flame retardant properties, and therefore, this property has been widely used to manufacture building materials and the like.

By the way, molded products made of phenolic resin have brittle properties as they are, and this property is particularly noticeable in foamed products, so it is generally reinforced with reinforcing fibers such as glass fibers.

[Problems with conventional technology]

However, since the raw material liquid phenol resin generally has a high viscosity higher than IOP, it is difficult to uniformly impregnate stranded glass fibers, and even if the immersion time is long, the resin impregnation state will not be dense. There was a problem in that it was difficult to obtain uniform product strength because it was easy to create problems.

[Invention tries to solve! ! 1! [Problem] In view of the above-mentioned problems, the present invention has been developed by impregnating even stranded reinforcing fibers with resin uniformly and sufficiently in the east direction of the fibers,
The purpose of this invention is to provide a method for impregnating fibers with liquid phenolic resin so that molded products with excellent strength can be obtained.

[Technology that led to solving the problem]

That is, the method for impregnating fibers with liquid phenolic resin of the present invention involves diluting a liquid phenol resin stock solution with a solvent, dipping stranded reinforcing fibers in the diluted stock solution to permeate it, and then drying the reinforcing fibers impregnated with the diluted solution. It is characterized by volatilizing and removing the solvent.

[Effect]

In order to uniformly impregnate stranded reinforcing fibers with resin, the resin to be impregnated must have low viscosity and high fluidity.

Therefore, the resin is diluted with a solvent that only increases fluidity without affecting the properties of the resin, and strands of reinforcing fibers are immersed in this. After the fibers are impregnated, only the solvent is volatilized. Once removed, the resin remains between the constituent fibers of the strand, allowing for uniform impregnation.

〔Example〕

Next, the present invention will be explained in detail.

Ethyl alcohol was added as a solvent to a liquid phenol resin having a viscosity of 10P to give a viscosity of 5P.

A glass fiber roving was dipped into this to impregnate it with the diluted resin solution.

Next, this glass fiber roving was dried, the solvent was removed by volatilization, and this was used as a reinforcing fiber to form a molded article using a pultrusion molding machine together with a thermosetting phenol resin in a conventional manner.

When the bending strength of a molded article with a radius of 5 mm and a length of im was measured, the results shown in Table 1 were obtained.

The comparative examples in Table 1 were molded using fibers impregnated with liquid phenol resin without dilution.

Table 1 [Effects] As explained above, this invention allows even high viscosity liquid resins to be diluted with a solvent that does not affect the composition of the resin, so the viscosity can be lowered without affecting the properties of the resin. Impregnation can be carried out uniformly, and if the solvent is removed by volatilization, the influence of this solvent is eliminated, so the matrix strength of the molded product is not affected, resulting in a molded product with uniform strength and excellent strength. It has the advantage of being able to mold FRP.

Claims (1)

[Claims] (1) A liquid phenolic resin stock solution is diluted with a solvent, stranded reinforcing fibers are immersed in the diluted stock solution, and the reinforcing fibers are soaked in the diluted stock solution.Then, the reinforcing fibers impregnated with the diluted solution are dried to volatilize and remove the solvent. Method for impregnating fibers with liquid phenolic resin.