JPH01118532A - Glass fiber sheet for reinforcing phenol resin foam - Google Patents

Abstract

PURPOSE:To provide the title sheet giving a phenol resin foam having excellent wear resistance, strength etc., by binding glass fibers surface-treated with an inorg. binder with a binder soluble in a foamable phenol resin soln. CONSTITUTION:Glass fibers are surface-treated with an inorg. binder (e.g., silica sol). A web is made of the surface-treated glass fibers, which are bound with a binder soluble in a foamable phenol resin soln. (e.g., polyvinyl alcohol or carboxymethyl cellulose) to prepare a glass fiber sheet. By reinforcing a phenol resin foam with this glass fiber sheet, neither deterioration of glass fibers nor curing interference due to elution of alkali component occurs and, as the binder is successively dissolved, the glass fibers are homogeneously dispersed in the foam.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a glass fiber sheet used for glass fiber reinforced phenolic resin foams used in building materials, heat insulation materials, and the like.

[Prior art and problems] In general, phenolic resin foams are lightweight and
Although it has many properties such as heat insulation, chemical resistance, dimensional stability, and nonflammability, it has extremely low abrasion resistance and bending strength, so attempts have been made to reinforce it with glass fiber.

Conventionally, this reinforcement method includes a method in which glass fibers are mixed in a phenol resin solution in advance and foamed, and a method in which a glass fiber nonwoven fabric is impregnated with a phenol resin solution and foamed, as shown in Japanese Patent Application Laid-Open No. 49-54678. was taken. However, the former method has the disadvantage that it is not possible to obtain a foam in which the glass fibers are uniformly dispersed because the specific gravity of the glass fibers is large and the fibers tend to be locally unevenly distributed.
In the latter method, the bonds between the fibers of the glass fiber non-woven fabric are strong, so the glass fibers do not disperse into the foam, and the glass fibers only cover the thickness of the glass fiber non-woven fabric! It had the disadvantage that it could not be reinforced with 1[.

In order to overcome the drawbacks of these conventional methods, the applicant previously proposed in Japanese Patent Application No. 180,770/1983 that a phenol resin solution was developed using a glass fiber non-woven fabric bonded between glass fiber wears using a binder dissolved in a foamable phenol resin solution. A method for manufacturing resin foam was proposed. According to this method, when the glass fiber nonwoven fabric is impregnated with a foamable phenolic resin solution, the binder in the nonwoven fabric is sequentially dissolved,
and) It was thought that a phenolic resin foam with high bending strength and abrasion resistance could be obtained because the glass fibers were uniformly dispersed in the foam as the enol resin expanded. However, even in this method, the phenol resin may inhibit curing, making it impossible to obtain a uniform fiber-reinforced foam. The reason for this is not clear, but it is thought that the foamable phenolic resin solution is usually heated and cured by an acid catalyst, so the glass fibers are affected by this and elute the alkaline component, which hinders the action of the acid catalyst. . If this curing inhibition occurs, curing time will be prolonged and productivity will be reduced, foams with irregular expansion ratios will be created, and glass fibers will not be uniformly dispersed in the foam, resulting in This results in the disadvantage that the reinforcing effect is not sufficiently exerted.

For this reason, the present inventors further proposed a glass fiber sheet for foams using acid-resistant glass fibers in Japanese Patent Application No. 62-69536. Alkaline components do not elute from this glass fiber sheet, and curing is not inhibited.
A uniform foam could be obtained. However, for example, when using acid-resistant glass fibers treated with a treatment agent containing a coupling agent, the bending strength decreases even though the glass fibers are uniformly dispersed in the foam. A phenomenon was observed. This is thought to be because the acid-resistant treated glass fibers have high bonding properties with the phenolic resin matrix, which causes the glass fibers to lose their degree of freedom in the matrix, making them more likely to break.

[Purpose of the Invention] The present invention has been made in order to eliminate the drawbacks of the above-mentioned prior art. The glass fibers can be uniformly dispersed,
Moreover, it is an object of the present invention to provide a glass fiber sheet from which a phenolic resin foam having high bending strength can be produced.

[Structure of the invention] The present invention provides glass fibers surface-treated with an inorganic binder,
This is a glass fiber sheet for reinforcing a phenolic resin foam, characterized in that it is bonded with a binder that is dissolved by a foamable phenolic resin solution.

The inorganic binder used in the present invention is suitably one whose main components are silica, alumina, zirconia, phosphoric acid, etc., and whose alkali component content is less than 2%, or which does not contain any alkaline components.For example, silica sol, alumina sol, Acid aluminum and the like are used. These inorganic binders are mixed with starch, a thickener such as polyvinyl alcohol, a surfactant, or a clay mineral or an inorganic powder, if necessary, and are attached to the surface of the glass m-fiber. Glass fibers surface-treated with this inorganic binder have acid resistance, are not affected by the acid catalyst contained in the foamable phenolic resin solution, and do not inhibit curing when the foamable phenolic resin solution is heated and cured.

In addition, since this glass fiber does not use a coupling agent or the like to obtain rFl acidity, it does not form an unduly strong bond with the phenolic resin that is the matrix, and can be used in the foam. , since it leaves a certain degree of freedom, it also has excellent bending strength.

It is preferable that these p# and machine binders are treated and attached to the glass fibers when spinning the glass fibers m, but they can be treated by immersing the raw material mass after cutting the fibers in a treatment solution, or by treating them at the time of sheet formation or after sheet formation. It may be attached by spraying or impregnating with a liquid. The solid content of this inorganic binder is 0.05 to 5.0% per fiber.
If it is less than 0.05%, sufficient acid resistance effect cannot be obtained, and if it exceeds 5.0%, bonding force acts between the glass fibers, making it difficult to disperse them sufficiently during foaming. Therefore, it is preferable to attach the inorganic binder to the glass fibers so that the entire surface of the glass fibers is covered with a film of the inorganic binder as thin as possible.

In addition, the glass fiber has a fiber length of 2 to 50H and a fiber diameter of 3 to 2.
A material having a diameter of 0 μm is preferably used. This has a fiber length of 21
If it is less than 1 Im, there will be no sufficient reinforcing effect and a strong foam will not be obtained. If it exceeds 50 mm, the dispersibility of the fibers will drop significantly and it will not be possible to disperse them uniformly in the foam. be.

In addition, when the fiber diameter is less than 3 μm, the resulting glass fiber sheet tends to become dense and impregnated with the phenol resin solution, while when it exceeds 20 μm, the reinforcing effect decreases and gives a tingling sensation to the skin. Therefore, work efficiency is significantly reduced.

The glass fiber sheet of the present invention is obtained by forming glass fibers surface-treated with the above-mentioned inorganic binder using a dry or wet method, and bonding the glass fibers with a binder that is dissolved in a foamable phenolic resin solution. .

The weight of the fibers that make up this glass fiber sheet is 30 to 5
00g/n+2 is desirable; if it is less than 30g/m2, the strength of the resulting phenolic resin foam will be insufficient;
If it exceeds 500 g/n+2, it will tend to become dense, impregnating the phenol resin solution will deteriorate, and even if the amount of fiber is increased beyond this, the reinforcing effect will not improve.

Furthermore, it is desirable that the fibers constituting the glass fiber sheet be oriented randomly, since this increases the mechanical strength of the resulting foam. However, if required depending on the application, it may be oriented in one or more specific directions.

Note that synthetic fibers, asbestos fibers, ceramic lft, carbon fibers, mineral fibers, etc. may be mixed and used in the glass fiber sheet as required.

A binder is provided to the glass fiber sheet by internally adding it during wet papermaking, or by spraying or impregnating the wet or dry wear.

The binder used here must be soluble in the foamable phenolic resin solution, and is therefore appropriately selected depending on the foamable phenolic resin solution used. for example,
Usually used foaming phenolic resin solutions mainly consist of resol-type phenolic resin emulsions and are water-based or alcohol-based, so the binders include polyvinyl alcohol, vinyl acetate/polyvinyl alcohol copolymers, etc. that are soluble in these solvents. Carboxymethylated cellulose, polyacrylamide, ethylene/vinyl acetate copolymer, polyvinyl acetate, and the like are preferably used. It is desirable that the dissolution of this binder occurs as the phenolic resin foams and hardens due to heating. For example, when using a water-based phenolic resin solution, it will not dissolve just by impregnating it, but when it becomes hot water by heating. Particular preference is given to using soluble, hot water-soluble binders. It is desirable that the amount of the binder adhered is 1 to 10% based on the weight of the glass fiber sheet; if it is less than 1%, the shape of the glass fiber sheet cannot be maintained, resulting in poor handling.
%, these components will be contained in a large amount in the foam, resulting in a decrease in the nonflammability of the foam and moisture absorption. The form of the binder is preferably fibrous or granular when it is added internally to glass fiber wear, and it is preferably in the form of a solution such as an emulsion when the wear is sprayed or impregnated.

When the glass fiber sheet of the present invention is impregnated with a foamable phenolic resin solution that is cured by an acid catalyst, heated, and foamed and cured, the binder that binds the glass fibers is sequentially dissolved, and the glass fibers are made of phenolic resin. As it foams, it is dispersed extremely uniformly and in layers throughout the foam. At this time, since glass fibers whose surface has been treated with an inorganic binder are used as fibers, the fibers do not undergo any deterioration due to acid catalysts, and alkaline components do not elute, so the phenolic resin hardens during foaming. It does not cause any obstruction. In addition, since the glass fibers are coated with an inorganic binder that does not have a high bonding property with the phenolic resin, they are not completely fixed to the phenolic resin matrix and have a certain degree of freedom within the 7 trix, such as bending. When such stress is applied, the strain can be alleviated by the slight movement of the glass fibers, so the resulting phenolic resin foam has excellent bending strength and abrasion resistance. Therefore, by using the glass fiber sheet of the present invention, a phenolic resin foam with uniformly dispersed glass fibers and excellent abrasion resistance and bending strength can be obtained without any manufacturing troubles.

(Example 1) 40 parts of colloidal silica, 40 parts of starch, 20 parts of surfactant
When spinning E-glass fibers with a fiber diameter of 13μn1, a thick edge treatment solution consisting of Created fiber. Next, 100 parts of glass fibers cut into 25 m lengths and 4 parts of polyvinyl alcohol fibers soluble in 60°C hot water were thoroughly mixed and dispersed in water, and wet-formed to produce a fabric with a basis weight of 300 g/m2 and a thickness of 1.5+n+y+. A glass fiber sheet was obtained.

The obtained glass fiber sheet was immersed in a 20% aqueous solution of para-toluenesulfonic acid at a temperature of 90° C. for 1 hour, and the weight loss rate was examined, and the results are shown in Table 1.

In addition, a resol type phenolic resin (C-570 C-570, Self-En, manufactured by Dainippon Ink & Chemicals) was added to the above glass fiber sheet.
1) Impregnated with 30003/m2 of a foamable phenolic resin solution consisting of 100 parts of balatoluenesulfonic acid, 10 parts of balatoluenesulfonic acid, and 5 parts of trichlorotrifluoroethane, and 20+?
Pour into a mold of II x 30 x 611 II+ and heat to 80
When the foam was foamed and cured by heating at .degree. C. for 30 minutes, a glass fiber-reinforced phenol resin foam with no uneven foaming or insufficient curing was obtained, and the glass fibers were uniformly dispersed in the foam. The bending strength of this phenolic resin foam was measured according to JIS-7221 and is shown in Table 1.

(Example 2) A glass fiber sheet was obtained in which 1% (solid content) of colloidal silica was attached to the glass fiber sheet of Example 1 by spraying based on the weight of the glass fibers.

The obtained glass fiber sheet was immersed in a 20% aqueous solution of para-toluenesulfonic acid at a temperature of 90° C. for 1 hour, and the weight loss rate was examined, and the results are shown in Table 1.

Further, a glass fiber reinforced phenolic resin foam was produced in the same manner as in Example 1, and its bending strength was measured and shown in Table 1.

(Example 3) A glass fiber sheet was obtained by spraying an inorganic binder consisting of 50 parts of colloidal silica and 50 parts of alumina sol onto the glass fiber sheet of Example 1 in an amount of 1% (solid content) based on the weight of the glass fibers. Ta.

The obtained glass fiber sheet was immersed in a 20% aqueous solution of para-toluenesulfonic acid at a temperature of 90° C. for 1 hour, and the weight loss rate was examined, and the results are shown in Table 1.

Further, a glass fiber reinforced phenolic resin foam was produced in the same manner as in Example 1, and its bending strength was measured and shown in Table 1.

(Example 4) A thick edge treatment liquid consisting of 80 parts of starch and 20 parts of surfactant was
When spinning E-glass fibers with a fiber diameter of 13 μm, a glass fiber was created with a solid content of 0.12 parts based on the weight of the glass fiber attached to the surface of the glass fiber.
After thoroughly mixing and dispersing 100 parts of glass fibers cut into 5-pieces and 4 parts of polyvinyl alcohol fibers soluble in 60°C hot water in water and performing wet papermaking, this sheet was sprayed with colloidal silica to reduce the weight of the glass fibers. 1% (
Solid content) attached, basis weight 300g/w2, thickness! -5
A glass fiber sheet of nm size was obtained.

The obtained glass fiber sheet was immersed in a 20% aqueous solution of para-toluenesulfonic acid at a temperature of 90° C. for 1 hour, and the weight loss rate was examined, and the results are shown in Table 1.

Further, a glass fiber reinforced phenolic resin foam was produced in the same manner as in Example 1, and its bending strength was measured and shown in Table 1.

(Comparative Example 1) A raw-grade treatment liquid consisting of 80 parts of starch and 20 parts of surfactant was
When spinning E-glass fibers having a fiber diameter of 13 μm, a glass fiber was prepared in which 0.12 parts of solid content was attached to the surface of the glass fiber based on the weight of the glass fiber. Then this fiber is
100 parts of glass fiber cut into 5 m lengths and 4 parts of polyvinyl alcohol fiber soluble in 60°C hot water were thoroughly mixed and dispersed in water, and wet-processed to form a paper with a basis weight of 300 g/n+2 and a thickness of 1.5% w. A glass fiber sheet was obtained.

The obtained glass fiber sheet was immersed in a 20% aqueous solution of para-toluenesulfonic acid at a temperature of 90° C. for 1 hour, and the weight loss rate was examined, and the results are shown in Table 1.

Further, a glass fiber reinforced phenolic resin foam was produced in the same manner as in Example 1, and its bending strength was measured and shown in Table 1.

(Comparative Example 2) A mixed solution containing 95 parts of phenolic resin and 5 parts of N-phenyl-3-aminopropyltrimethoxysilane (silane coupling agent) was sprayed onto the glass fiber sheet of Comparative Example 2. 1% by weight (solid content)
A glass fiber sheet was prepared.

The obtained glass fiber sheet was immersed in a 20% aqueous solution of balatoluenesulfone vi at a temperature of 90° C. for 1 hour, and the weight loss rate was examined, and the results are shown in Table 1.

Further, a glass fiber reinforced phenolic resin foam was produced in the same manner as in Example 1, and its bending strength was measured and shown in Table 1.

As is clear from Table 1, all of the examples had low weight loss rates, good acid resistance, and excellent bending strength.

[Effects of the Invention] The glass fiber sheet of the present invention is made by bonding glass fibers whose surface has been treated with an inorganic binder using a binder that is dissolved by a foamable phenolic resin solution. , glass m1t
The bonding agent of the glass fiber sheet is gradually dissolved, and the glass fibers are uniformly distributed in the foam as the phenol resin foams. distributed to Therefore, the phenolic resin foam using the glass fiber sheet of the present invention has an extremely homogeneous reinforced structure. Also, glass m1
Since tt is coated with an inorganic binder, it is not fixed to the phenolic resin and has a certain degree of freedom in the matrix, so it exhibits good abrasion resistance and bending strength, and is suitable for building materials and insulation. It can be suitably used for materials such as materials. As described above, the glass m of the present invention
1tt sheet is very useful as a reinforcing material for phenolic resin foams.

Patent applicant Nippon Vilene Co., Ltd.

Claims (1)

[Claims] (1) A glass fiber sheet for reinforcing phenolic resin foam, characterized in that glass fibers surface-treated with an inorganic binder are bonded with a binder that is dissolved by a foamable phenolic resin solution.