JPS5815450B2 - Method for enhancing cement alkalinity resistance of glass fiber with low zirconia content - Google Patents

Description

[Detailed Description of the Invention] Attempts to improve strength and durability by mixing glass fibers into mortar or plaster containing Portland cement, lime milk Ca(OH)2, water glass, etc. have been made for quite some time. Since then, people skilled in the art both domestically and internationally have tried this method, but most of them have not been very effective.

The main reason for this is that free Ca (OH) 2 , Mg (OH) 2 and KO are released during the hydration solidification reaction of these cements.
H, NaOH, etc. soak the surface of the glass fiber and reduce the tensile strength of the glass fiber, and even after solidification of Portland cement, etc., Ca(OH) remains for a long time.
This is because 2 and the like are contained in the form of an aqueous solution.

Therefore, in general, the cement alkalinity resistance of many glasses is
Since its acid resistance and water resistance are extremely low, it is unsuitable as a reinforcing fiber material for Portland cements and calcareous cements that contain a large amount of alkaline components.

The addition of zirconia (ZrO2) has long been known as an effective ingredient for increasing the cement alkalinity resistance of glass, and therefore, what is called cement alkali resistance glass almost always contains ZrO2. ing.

Many of these contain Z of about 4 to 10% (by weight).
The r02 content appears to have achieved its purpose.

However, for products with a large surface area ratio such as glass fibers, sufficient cement alkali resistance cannot be achieved unless the ZrO2 content is increased to 10% to 20%.

By the way, containing 10% or more of ZrO2 in glass fibers not only makes it extremely difficult to melt the raw material mixture, but also increases the liquidus temperature of the molten glass, so in the case of glass fibers, etc. Increases the frequency of threading and significantly reduces spinning efficiency.

Here, the present invention uses a mixed aqueous solution containing a strong inorganic salt of zirconium, such as zirconium chloride, zirconium sulfate, or zirconium nitrate, and a strong inorganic salt of hafnium, that is, hafnium chloride, hafnium sulfate, or hafnium nitrate, to achieve a low ZrO2 content of 4. ~10%, preferably 6-8% glass fibers are immersed to cause ion exchange on the surface of the glass fibers, and the glass fibers with low ZrO2 content form a dense surface of zirconium and hafnium. This method improves the alkali resistance of cement. According to this method, a high content of ZrO2, that is, 10% or more2
It was found that it is much easier to maintain a tensile strength of the same level or higher than that of 0%.

Furthermore, it was found that cement alkali resistance was similarly improved.

Examples will be described below.

EXAMPLE Zirconium chloride and hafnivum chloride were used in this example.

The concentrations are shown in the table below. The procedure is to first prepare an aqueous solution with a concentration of 1.0% zirconium chloride and 1.0% hafnium chloride in a beaker, then put this in a boiling water bath and raise the temperature to 90℃ or higher. A glass fiber with a low Z r02 content of 7%, its fiber diameter is 2.
50 pieces of 20 pieces of 0-16μ and 100cIfL length.
Cut at cIn and make two sets as follows: A"
Divide A into 20 pieces of 50 cIrLX and 20 pieces of 51 CIIL , Tensile load measurements were performed on the fibers of the untreated portion and the treated portion, and the strength was compared.

The average value of the 20 pieces of Q is as shown in "A" on the left side of the following table, indicating that the tensile strength of the treated part is much improved.

Next, the other B" group was taken out and a 10 m portion of one end thereof was immersed in the same manner as described above. After washing with water and drying as described above, it was immediately immersed as follows.

That is, prepare a stainless steel beaker with a capacity of 200 m1,
Take 100 ru of Boltland sescint supernatant liquid, and add 10 C/rL of one end of the above fiber (already containing ZrCl4
1.0% and HfCl4 (the part that has been treated with the aqueous solution of 1.0%) is immersed in this solution.

That is, a beaker is placed in a boiling water bath and kept at 90°C or higher for 2.5 hours, after which the fibers are taken out from the beaker and thoroughly washed with water.

Confirm the completion of washing by dropping phenolphthalene.

The fibers are then dried in a desiccator for 24 hours.

After drying, the fibers were pulled out one by one from the bundle, and tensile strength tests were conducted on the treated and untreated portions of 20 fibers from both ends.The average values are shown in Table B below, and the results are as follows: It was found that even when immersed in a liquid (pH 12 to 14) at high temperature, the tensile strength did not decrease, but rather increased.

In the same manner as above, the diameter of the fiber used twice was 21 to 17μ, the diameter of the fiber used three times was 22 to 18μ, and the diameter of the fiber used four times and five times was 20 to 16μ.The results are shown in the following table. In both cases, the tensile strength is shown to be improved, and even when immersed in the Portland cement supernatant liquid, the tensile strength is increased.

This experiment shows that the mixing ratio of zirconium chloride (ZrC14) and hafnium chloride (HfC14) is 2% of the entire mixed solution, and the allocation can be made appropriately.

As described above, the present invention makes it possible to form a dense corrosion-resistant layer on the surface of glass fibers using two types of ions with different ionic radii, and has improved cement alkali resistance and tensile strength, and is highly durable. Good results were obtained.

Claims (1)

[Claims] 1 Glass fiber containing 4 to 10% by weight of zirconia component and 0.5 to 1.5% by weight of zirconium inorganic strong acid salt
and 1.5 to 0.5% by weight of a strong inorganic salt of hafnium, and the total concentration of these salts is 2.0% by weight. A method for enhancing cement alkalinity resistance of glass fibers with a low zirconia component, which comprises performing ion exchange to form a dense surface of zirconium and hafnium.