JPS589775B2 - Glass fiber surface treatment method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for surface treatment of glass fibers for imparting alkali resistance and the like to the glass fibers.

Recently, silicon oxide (Si) has been added to mortar, concrete, etc.
O2), calcium oxide (CaO), magnesium oxide (MgO), boron oxide (B2O3), sodium oxide (
It is becoming popular to increase the bending strength and other strength of cement molded products by mixing long glass fibers and short fibers whose main components are Na2O), potassium oxide (K2O), aluminum oxide (Al2O3), and lithium oxide (Li20). It is being done.

The thinner the thickness of the glass fibers, the higher the tensile strength and other strengths, and correspondingly, the stronger the bending strength, etc., of the cement molded product can be obtained, so it is recommended to use thin glass fibers. Recommended.

By the way, glass fibers having the above composition have a pH of
Although it has acid resistance in a wide range of pH 2 to 6, it does not have alkali resistance in the alkaline range of pH 9 to 12. Alkaline earth metal oxides such as Ca(OH)2, Mg(OH)2, etc. and alkali metal oxides such as Na2O, K2O, Li2O, etc.
, NaOH, KOH, and LiOH, resulting in a disadvantage that the strength of the glass fiber, especially the tensile strength, deteriorates.

In particular, in the case of thin glass fibers with a large surface area, the surface area that comes into contact with the alkaline components of cement increases, resulting in significant deterioration.

For this reason, methods for imparting alkali resistance to glass fibers have recently been proposed, such as organic surface coating methods using various resins and compositional substitution coating formation methods using various inorganic acids, but none of them have sufficient alkali resistance. cannot be applied to glass fibers, and there is still room for improvement, and a new method has been desired.

Therefore, the present inventors surfaced glass fibers with no alkali resistance or glass fibers with low alkali resistance containing 25% by weight or less of zirconium oxide with an aqueous solution of zinc lead or tin chloride, sulfate or nitrate, or a mixture thereof. A method for surface treatment of glass fibers has been proposed, which is characterized by forming an alkali-resistant protective coating on the surface of glass fibers (Japanese Patent Application No. 77166/1983 and Japanese Patent Application No. 106559/1983).

As a result of further intensive research to improve the inventions of the above-mentioned Japanese Patent Application Nos. 53-77166 and 1987-106559, the present invention has been made by combining zinc chloride and zinc silicofluoride among the above-mentioned inorganic compounds. It has been discovered that the alkali resistance can be further improved by using them together, and the present invention has been achieved.

That is, in the present invention, glass fibers with no alkali resistance or glass fibers with low alkali resistance containing 25% by weight or less of zirconium oxide are mixed with zinc chloride and zinc silicofluoride in a weight ratio of 1:1 to 9:1. This invention relates to a method for surface treatment of glass fibers, characterized in that the surface treatment is performed with an acidic aqueous solution containing a proportion of .

The present invention will be explained in detail below.

First, zinc chloride and zinc silicofluoride are mixed in a weight ratio of 1:1 to 9:
Add 1 part to water to prepare an acidic aqueous solution.

The acidic range is preferably pH 2 to 5, and the zinc chloride concentration in the acidic aqueous solution is preferably 5 to 25 wt%.

When the above acidic aqueous solution contains zinc chloride and zinc silifluoride in the above weight ratio range, a synergistic effect can be obtained and sufficient alkali resistance can be imparted to the glass fibers, but when the weight ratio is outside the above range, a synergistic effect can be obtained. No effect is obtained, and glass fibers with good alkali resistance cannot be obtained.

The aqueous solution prepared as described above was mixed with SiO2, A1
203, B203, MgO, Cab, Bad, K2O,
So-called E-glass, C-glass, A-glass, S-glass made of appropriate combinations of Li20, Fe203, Ti02, etc.
-Glass, M-Glass or other non-alkali resistant glass long fibers or short fibers or the above glass fibers with 25% Zr02
It is applied to glass long fibers or short fibers (hereinafter referred to as glass fibers) with low alkali resistance such as G-glass fibers containing less than % by weight by an appropriate method such as dipping, spraying, or coating. The fibers are surface-treated to form an alkali-resistant protective coating on the surface of the glass fibers.

When the above-mentioned surface treatment is performed, for example, by a dipping method, a short dipping time of about 1 to 3 seconds is sufficient.

The formation of an alkali-resistant protective film is thought to be due to the following reaction mechanism.

When surface-treating silicate glass fibers with an aqueous solution of ZnCl2 and ZnSiF6, cations such as Na+, Li+, Ca2+, Mg2+, Ba2+, etc. bind with weak bonding force in the Si-00 network structure. However, when an aqueous solution of ZnCl2 and ZnSiF6 acts on this glass surface, cations such as Na 10 easily and quickly combine with highly reactive Cl anions, forming NaCl, LiCl, and C.
ac12,? Salts such as gC12 and BaC1 are eluted from the glass surface, and Zn2+ and the like are replaced with cations such as Na1, and a colloidal zinc protective film is instantly formed.

This colloidal zinc protective coating is stable against alkalinity and weak acidity at room temperature.

Next, the surface-treated glass fibers as described above are washed with water and then dried to form a surface-treated glass fiber product.

As mentioned above, according to the surface treatment method of the present invention, a colloid protective film of zinc and zinc silicofluoride is formed on the surface of the glass fiber, so the glass fiber surface-treated by the method of the present invention has high resistance. It not only has alkalinity, but also has properties such as weathering resistance, water resistance, acid resistance, and flexibility.

Therefore, when glass fibers surface-treated by the method of the present invention are mixed with mortar, concrete, or plastic, cement molded articles or plastic molded articles with high strength such as bending strength are formed.

Furthermore, since the glass fibers surface-treated by the method of the present invention have flexibility, a cement molded product is formed that does not cause problems such as cracks.

EXAMPLES Hereinafter, the present invention will be specifically explained by showing Examples and Comparative Examples.

Examples and Comparative Examples ZnCl2 and Zn were used at the respective weight ratios shown in Table 1 below.
SiF6 is added to water and mixed to form the p shown in Table 1.
An acidic aqueous solution of H was prepared.

In addition, in Examples 1 to 3 and Comparative Examples 1 and 2 shown in Table 1, the ZnCl2 concentration in the acidic aqueous solution was all 10 wt%.
It was prepared as follows.

Each of the above various acidic aqueous solutions has a diameter of 13μ and a length of 25
2 g of strands of 400 mm E-glass fibers (tensile strength 4.539 kg/400H) were immersed for 1.5 seconds at room temperature.

Next, the surface-treated glass fibers were immediately washed with water and then dried at 80±5°C.

In order to examine the alkali resistance of each surface-treated glass fiber, the surface-treated glass fiber was heated at 80±3°C in a thermostatic chamber.
After 240 hours of immersion in a Portland cement extract with a pH of 12 maintained at ℃, it was taken out, washed with water, dried,
Next, the alkali reduction rate and the degree of decrease in tensile strength were measured.

The obtained alkali reduction rate and tensile strength were determined as Examples 1 to 3 for the above acidic aqueous solutions in which the mixing ratio [of subsalt chloride and zinc silicofluoride] was within the range of the present invention, and the range The other examples are shown in Tables 2 and 3 as Comparative Examples 1 and 2.

Furthermore, for comparison, the following various comparative experiments were also conducted.

(A) Glass fiber without surface treatment (Comparative Example 3), (
B) Surface treatment with a 10 wt % acidic aqueous solution of ZnCl2 alone at pH 3.5 (Patent application No. 77166/1983 by the present applicant)
Comparative Example 4), (C) ZnSiF at pH 2.5
6. Surface treatment with 10 wt% acidic aqueous solution (Comparative Example 5)
).

The results obtained in Comparative Examples 3 to 5 above are also listed in Tables 2 and 3.

As is clear from Tables 1 to 3 above, glass fibers surface-treated with an aqueous solution containing ZnC12 and ZnSiF6 in the quantitative ratio within the range of the present invention have almost no tensile strength even when immersed in cement extract. It does not deteriorate, has little alkali weight loss, and has sufficient alkali resistance.

In particular, ZnCl2 and ZnSiF6 were mixed at 80% by weight: 20
Glass fibers having the best alkali resistance can be obtained when the surface is treated with an aqueous solution containing the glass fibers in a weight ratio of 4:1.

On the other hand, when glass fibers without surface treatment are immersed in cement extract, their tensile strength deteriorates to the point where they become unmeasurable, and the alkali loss is extremely high at approximately 40%, meaning that they have no alkali resistance at all. It turned out that it didn't.

It was also found that the combined treatment of Examples 1 to 3 of the present invention could impart better alkali resistance to glass fibers than the single treatment of Comparative Examples 4 to 5.

Furthermore, Examples 1-
It was also found that in the case of No. 3, a better effect was obtained than in Comparative Examples 1 and 2, in which the combined treatment was carried out at an amount ratio outside the range.

It should be noted that, unexpectedly, the tensile strength (4.502 k
g/cm2) was found to be almost the same as the tensile strength of the raw glass fiber strand before surface treatment (4.539 kg/cm2).

Claims (1)

[Claims] 1 Glass fibers with no alkali resistance or glass fibers with low alkali resistance containing 25% by weight or less of zirconium oxide are mixed with zinc chloride and zinc silicofluoride in a weight ratio of 1:1.
A method for surface treatment of glass fibers, characterized in that the surface is treated with an acidic aqueous solution containing a ratio of ~9:1 to form an alkali-resistant protective coating on the surface of the glass fibers.