JPS5934663B2 - Glass composition with alkali resistance - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a glass composition that has alkali resistance and can be made into fibers.

Generally, glass fibers for reinforcing cement, mortar, etc. with a high alkali-9 content are required to have alkali resistance, and to date, alkali-resistant glass compositions for glass fibers with various compositions have been developed.

As a result of numerous studies on alkali-resistant glass compositions, the present inventors found that a sio2-2ro2-alkali metal oxide-alkaline earth metal oxide system with a low content of alkaline earth metal oxides We have discovered that extremely high alkali resistance can be obtained by introducing copper oxide into a glass composition.

That is, it has been discovered that one of the glass compositions with extremely excellent alkali resistance is contained within the following ratio range. Ingredients Weight % SiO251-70 Zr028-20 Alkali metal oxide 14-24 Alkaline earth metal oxide 1-8 Cu01-10 The glass composition of the present invention has a low content of alkaline earth metal oxide. By introducing CuO into a 2ro2-alkali metal oxide-alka9 earth metal oxide glass composition, it is characterized by extremely high alkali 9 resistance.

In the glass composition of the present invention, the content of SiO2 is 5
If the amount is less than 1% by weight, extremely high alkali resistance cannot be obtained and devitrification tends to occur.

Moreover, if the amount exceeds 70% by weight, it becomes poorly soluble, so Si
The content of O2 is preferably in the range of 51 to 70% by weight.
In the glass composition of the present invention, if the content of ZrO2 is less than 8% by weight, extremely high alkali resistance cannot be obtained. A range of 8 to 20% by weight is desirable.

In the glass composition of the present invention, if the content of the alkali metal oxide is less than 14% by weight, the glass composition becomes poorly soluble;
The liquidus temperature also increases.

Further, if the content exceeds 24% by weight, extremely high alkali resistance cannot be obtained, so the content of the alkali 9 metal oxide is preferably in the range of 14 to 24% by weight. Examples of alkali metal oxides include Na2OlK2O, Li, and O. If the amount of alkaline earth metal oxide added to the glass composition of the present invention is more than 8% by weight, it becomes easy to see through, so it is desirable that the amount of alkaline earth metal oxide added is 8% by weight or less.

Furthermore, alkaline earth metal oxides mainly including CaO are effective as viscosity reducing agents, and it is desirable to add 11% by weight or more. As the alkaline earth metal oxide, CaO
There are lMgOlBaO and the like. In the glass composition of the present invention, the effect of CuO has the effect of improving alkali resistance similar to the effect of ZrO, but among various aqueous alkaline solutions, the effect of preventing deterioration in cement extract is particularly remarkable.

If the CuO content is less than 1% by weight, very high alkali resistance cannot be obtained, and if it is more than 10% by weight, the effect on alkali resistance will decrease and the coloring property will be strong. The number of times has also increased significantly. That is, the glass is heated in a platinum container called a bushing, which has many holes at the bottom.
It is thought that as the amount of CuO added increases, the heat from the bushing is absorbed by the glass around the bushing, and the temperature difference between the bushing and the glass at the center of the bushing increases, making yarn breakage more likely. Therefore, the content of CuO is preferably in the range of 1 to 10% by weight. The present invention will be explained below with reference to Examples.

The glass sample shown in this example was prepared by placing a previously prepared glass raw material in a platinum crucible, melting it in an electric furnace at 1450° C. for 3 hours, and then cooling it in air at room temperature.

The alkali resistance test method shown in this example involves adding 3 kg of water to 1 kg of Portland cement, stirring well, allowing it to stand for 1 hour, filtering the supernatant liquid, and using the alkaline solution for testing (cement extract). , PH=13.
5).

Heat 100 cc of this test solution to 80°C, and add 4 grams of glass powder sample of 35 to 60 mesh into this solution at 10 cc.
After being immersed for days, the weight loss rate showed alkali resistance. The solubility test method shown in this example is 1001
Put 20 grams of glass raw material into a platinum crucible with a capacity of 1
The state of dissolution after holding at 500° C. for 1 hour was determined by visual observation.

O has a very good dissolved state, and 1Δ has a relatively good dissolved state. In addition, in order to further understand the melting state, 20 g of glass raw material was placed in a 1001 capacity alumina crucible and heated at a temperature increase rate of 200°C/hour, and taken out at 50°C intervals at a temperature of 1000°C or higher.
The temperature at which the peak indicating residual crystals disappeared was determined by X-ray diffraction.

The lower the temperature, the better the solubility. From the table, it can be seen that the glass sample of the example in which CuO was introduced has superior alkali resistance compared to the E glass of the comparative example and the sample of glass sample number.

Claims (1)

[Claims] 1% by weight of SiO_2 51-70%, ZrO_2
8 to 20% of CuO, 14 to 24% of alkali metal oxides, 1 to 8% of alkaline earth metal oxides, and 1 to 10% of CuO. 2 wt% SiO_2 58-64%, ZrO_2
12-16%, Na_2O 15-17%, CaO4
8% and 1 to 4% of CuO.