KR810000742B1 - Alkali resistant glass composition - Google Patents

Abstract

A glass for spinning alkali-resistant concrete-reinforcement fiber glass contains SiO2 54-60, ZrO2 13-16, Na2O 12-15, MnO 5.5-14, and CaO 0-7%. The amt. of MnO added to improve alk. resistance should be at least the amt. of CaO used; Mno+CaO is >=11%. Thus, a mixt. contg. SiO2 57.5, ZrO2 15.5, MnO 7.0, CaO 6.5, and Na2O 14.5 % is melted at 1350≰C in a Pt crucible and spun into 16μ diam. fibers. The glass has liquidus temp. 1195≰C and temp. at which viscosity is 1000p 1210≰C A low wt. loss was obtained when fibers were tested in alkali solns, including the filtrate from aq. portland cement.

Description

Glass composition

The present invention relates to glass compositions having good fiber-forming ability, in particular glass compositions suitable for producing good alkali resistant glass fibers for use as reinforcements for cement products.

The glass fibers used to reinforce cement products must have alkali resistance. It is known that addition of a certain amount of zirconium oxide to glass, especially alkali-containing glass, increases alkali resistance of the glass, and alkali resistant glass fibers can be produced. Representative glass compositions having such a zirconium oxide content are described in Japanese Patent Publication No. 40,126 / 74. The glass compositions described in this patent publication contain a large amount of zirconium oxide by 7 to 11 mole percent, but have a relatively low fiber-forming temperature of 1320 ° C. or lower, which is the case for conventional glass compositions containing zirconium oxide. It is considerably lower than the temperature above about 1450 ℃. However, a glass composition having a high zirconium oxide content has a high liquidus temperature and weak meltability, making it difficult to obtain a uniform molten glass and not easily forming fibers. For example, glass compositions having a high zirconium oxide content do not contain any alkali metal components and therefore are less soluble than E glass having a high fiber-forming temperature. In addition, its fiber-forming temperature is about 70-160 ° C. higher than that of E glass. Therefore, there are various drawbacks such as the fire retardant used in such a glass composition is extremely limited, the erosion of the fire retardant is remarkable, and the platinum bushing used for spinning the glass composition is shortened in life.

On the other hand, there are a number of methods for spinning glass fibers, for example, using a tempered flat nozzle plate and using a plurality of nozzles, a method using a nozzle plate having a plurality of tip nozzles, and between rows of tips. And a tip nozzle plate for arranging cooling wheels in parallel to cool the cone of molten glass formed at each tip. When glass compositions having a high zirconium oxide content are used for spinning, the device, in particular the cooling wheel, is damaged by the alkali component evaporating from the cone of alkali metal oxides in the glass composition, thus reducing stable spinning.

It is an object of the present invention to solve the above-mentioned shortcomings and to provide an alkali resistant glass composition containing zirconium oxide, which has good alkali resistance, good meltability, and is easily cooled.

It is another object of the present invention to provide a low fiber formation temperature, the same performance as E glass in fiber formation, and a spinning method capable of stably spinning the glass fibers without damaging the device, especially the cooling wheel, when using a tip nozzle plate. It is to provide a glass composition that can be used.

The glass composition of this invention has the following composition.

SiO ₂ 54-60 wt%

MnO 5.5-14 wt%

ZrO ₂ 13-16 wt%

CaO 7 wt% or less

Na ₂ O 12-15 wt%

Here, the total weight of MnO and CaO should be at least 11% by weight, and the weight of MnO should be equal to or greater than the weight of CaO.

In the glass composition of the present invention, the proportion of SiO ₂ is mainly limited to 54 to 60% by weight in order to properly maintain the viscosity of the molten glass upon melting. If this ratio is 54% by weight or less, the viscosity is too low compared with the liquefaction temperature, and as a result, the spinning becomes difficult. On the other hand, when this ratio exceeds 60 weight%, a viscosity will become too high to satisfy the objective of this invention.

The ratio of ZrO ₂ is limited to 13 to 16% by weight. If this ratio is 13% by weight or less, sufficient alkali resistance cannot be obtained. On the other hand, when this ratio is 16% by weight or more, the liquidus temperature rises rapidly, and spinning becomes difficult.

The ratio of Na ₂ O is limited to 12 to 15% by weight. If this ratio is 12% by weight or less, the meltability becomes insufficient, and the liquidity misleading increases, while when this ratio is 15% by weight or more, the viscosity decreases, so that the evaporation of the alkaline component from the cone increases.

The proportion of MnO should be 5.5-14% by weight, while the total weight of MnO and CaO should be at least 11% by weight and the weight of MnO should be equal to or greater than the weight of CaO. If the proportion of MnO is 5.5% by weight or less, and other conditions are satisfied, the liquidus temperature rises, the meltability deteriorates, and the molten glass passing through the nozzle cannot be easily cooled, and the alkali resistance also decreases. On the other hand, when this ratio is 14 weight% or more, a viscosity falls and it cannot perform spinning suitably.

CaO이고, MnO 및 CaO의 전체 중량이 11중량％ 이상인 조건하에서 MnO 대신에 7중량％까지 함유할 수 있다. CaO의 비율이 7중량% 이상이거나 또는 CaO＞MnO인 경우, CaO는 MnO의 기능을 억제하는 경향이 있으며, 또한 액상 온도를 크게 상승시키는 경향이 있다. ZrO₂와 추가로 소량의 Al₂O₃를 함유하는 종래의 알칼리 내성 유리 조성물과 달리, Al₂O₃는 액상온도의 상승과 알칼리내성의 저하를 방지하기 위해 본 발명의 유리 조성물에 첨가해서는 안된다. 또한, B₂O₃와 P₂O₅가 알칼리 내성에 대한 저하 성분으로서 작용하기 때문에, 이 성분들을 본 발명의 유리 조성물에 첨가해서는 안되지만, 이 성분들을 불순물로서 1중량％까지 허용할 수 있다.CaO is MnO

It is CaO and can contain up to 7 weight% of MnO instead of MnO on condition that the total weight of MnO and CaO is 11 weight% or more. When CaO ratio is 7 weight% or more, or CaO> MnO, CaO tends to suppress the function of MnO, and also tends to raise a liquid phase temperature significantly. Unlike conventional alkali resistant glass compositions containing ZrO ₂ and additionally small amounts of Al ₂ O ₃ , Al ₂ O ₃ should not be added to the glass compositions of the present invention to prevent rise in liquidus temperature and deterioration of alkali resistance. . In addition, since B ₂ O ₃ and P ₂ O ₅ act as reducing components for alkali resistance, these components should not be added to the glass composition of the present invention, but these components can be allowed up to 1% by weight as impurities.

The glass composition of the present invention may contain components commonly used as a purifying agent, such as CaF ₂ , Na ₂ SO ₄ , Sb ₂ O ₃ , AS ₂ O ₃ , and the like as other fiber forming glass compositions. In addition, the glass composition of the present invention is obtained from refractory materials of melting apparatus or spinning apparatus as impurities and other compounds such as K ₂ O, Al ₂ O ₃ , Fe ₂ O ₃ , TiO _2, and the like contaminated with the raw materials of the individual glass components described above. The compound, such as leached Cr ₂ O ₃ and SnO ₂ , may be contained at about 1% by weight or less.

In the glass composition of the present invention, the above object can be achieved by using individual components in a limited amount, and most importantly, a large amount of manganese oxide under the condition that the total weight of manganese oxide and calcium oxide is 11% by weight. That is, it is made to contain up to 5.5 weight%.

By containing a large amount of manganese oxide, the glass composition of this invention is extremely excellent in meltability, and is melted more easily than glass, and produces uniform molten glass. In addition, since the liquidus temperature of the glass composition can be lowered by about 1050 DEG C to 1200 DEG C, and the emission temperature thereof can be lowered, it can be spun under almost the same conditions as glass. Since the molten glass obtained by addition can be cooled easily, since evaporation of alkali is suppressed and a cooling wheel can be used for a long time, glass fiber can be stably spun and our fiber can become more resistant to alkali. There is.

More specifically, with the glass composition of the present invention, even if a large amount of ZrO ₂ is contained, the glass composition provides extremely good meltability and uniform glass. For example, a glass composition may be prepared by melting and melting a glass raw material mixture in a crucible by measuring the time required to make the area of the non-melt and the area of the melt equal on top of the crucible by melting. The conventional ZrO containing requires about 75 minutes, and the glass composition of the present invention requires only about 45 minutes by using 100 g of a raw material mixture which passes through a 200 mesh body and melts at 1350 ° C. This can be explained by the results shown in Table 2 below, where the glass compositions of the invention have extremely low viscosities and conventional ZrO ₂ containing glass compositions at the same liquidus temperature corresponds to half the viscosity. The good meltability of the glass composition of the present invention is due in part to the function of the manganese raw material, which is a strong flux.

Regarding the spinning of glass fibers, it is generally known that the larger the difference between the liquidus temperature and the spinning temperature, the better the spinning can be done. If the difference between the liquidus temperature and the spinning temperature is small, it is because crystals readily grow in the molten glass to cut the glass fibers until the molten glass passes through or after the nozzle. However, the spinning stability of the glass fiber is not limited to the difference between the liquid phase temperature and the spinning temperature as described above, and the uniformity of the molten glass, the viscosity gradient, the crystal growth rate, the ease of cooling, the number of nozzles per spin furnace, the fiber It is influenced by other factors such as diameter, winding rate, the actual use of the cooling wheel, the presence or absence of cooling aids such as a graded article.

For example, the problem of crystal growth arises especially when non-uniform portions such as filigree and fine crystal structures exist in the molten glass. In the case of uniform molten glass, spinning cannot be performed without difficulty even when the difference between the liquidus temperature and the spinning temperature is small. In addition, even when there is a significant non-uniformity in the molten glass, the molten glass passes through the nozzle, and crystal growth hardly occurs so that it can be maintained at a fairly high temperature until the fibers are cut before passing through the nozzle, so that the nozzle plate temperature Even when the temperature is set to the liquidus temperature, the spinning can be carried out without difficulty if the viscosity is appropriate. Even when a non-uniform structure having a tendency to grow into crystals is present in the molten glass immediately before passing through the nozzle, when the stream of molten glass has excellent cooling property, by a rapid cooling effect that suppresses the growth of crystals Stable spinning can be obtained.

Although the glass composition of the present invention has a relatively small drawback between the liquidus temperature and the spinning temperature (which generally means a temperature which exhibits a viscosity of 1000 poise), it is extremely good in spinning stability because This is because it has excellent meltability, very few non-uniformities causing crystal growth and deposition, widening the spinning operation by addition, and can rapidly cool the molten glass that has passed through the nozzle.

Easily cooled glass compositions of the present invention turn purple or brown because the manganese oxide contained in the glass composition partially changes to trivalent manganese. Except when using a bottle, there is a tendency for not wanting coloring of glass, but in this invention, coloring of glass can be used in consideration of the effect to be easily cooled. Since colored glass fibers are used in reinforcement cement products, there is no problem in using such colored glass fibers.

The molten glass passing through the nozzle is rapidly cooled to form a concave surface. In this case, heat waste is mainly due to radiation. When the glass is colored, in particular the surface of the molten glass is markedly colored, which is desirable in terms of stability of spinning. Commonly used radiation manipulation temperatures are those at which the kendo shows about 1000 poises. In the case of the glass composition of the present invention, the spinning operation temperature can be widely used, for example, a temperature exhibiting a viscosity of 400 to 500 poise, because the glass composition is easily cooled so that the molten glass is immediately after spinning. Because it is cooled. In addition, the glass fibers thus obtained have the advantage that the strength is enhanced as compared with the usual glass fibers due to rapid cooling. Another advantage is that after passing through the nozzle the evaporation of the alkaline component can be reduced to effective cooling, especially on the surface, thereby extending the life of cooling devices such as cooling wheels. Conventional glass containing 10% by weight or more of alkali components significantly evaporates the alkali components from the molten glass after passing through the nozzle, shortening the life of cooling devices such as cooling wheels, making the cooling wheels unusable for practical operation. Have drawbacks. In contrast, cooling wheels can be used in the glass compositions of the present invention.

By using the glass composition of this invention, the glass fiber which has the same or more practicability as the conventional alkali resistant glass fiber can be manufactured. Excellent performance of the glass fibers prepared using the glass composition of the present invention is, for example, a test for weight loss in an alkaline solution, a test for changing the strength of short fibers in an alkaline solution after a lapse of time, and a strength of a strand in an alkaline solution after a lapse of time. The change test and the flexural strength change test of the cement product reinforced with strands after the passage of time as described later.

11중량％ 이상일 경우, 알칼리내성의 증대가 명백히 인식되며, 최종적으로 약 30％ 정도의 실행성의 개량을 얻을 수 있다.It is known that glass containing zirconium oxide is excellent in alkali resistance. Components other than zirconium oxide naturally affect alkali resistance, for example, B ₂ O ₃ , P ₂ O ₅ and Al ₂ O ₃ act as components to inhibit alkali resistance, which greatly affects the retention of strength. . It is known that the alkaline earth metal component acts to increase the alkali resistance of the glass fibers. As a result of studying by the present inventors, manganese oxide also increases alkali resistance, and the effect is larger than that of metals with alkali. That is, alkaline earth metals, such as calcium oxide, are replaced with manganese oxide, MnO content is 5.5 weight% or more, and MnO + CaO

In the case of 11% by weight or more, an increase in alkali resistance is clearly recognized, and finally, about 30% of improvement in performance can be obtained.

The invention is specifically illustrated by the following non-limiting examples, where percentages are by weight unless otherwise indicated.

EXAMPLE

Meltability was tested using the individual glass compositions shown in Table 1. The liquidus temperature and the viscosity of each glass composition are shown in Table 2.

The test method is as follows. The glass raw material mixtures of each system were put in a platinum crucible in an electric furnace and melted. In the initial stage, the melt sinks to the bottom and the non-molten portion stays on top. The non-melt layer is thinner so that the molten glass is visible in the upper center of the ceramic. The time required for the non-melt area and the area of the viewable part of the molten glass to be equal was measured after using the raw material mixture in the crucible to measure the meltability.

100 g of the raw material mixture passing through the 200 mesh body was melted at 1350 ° C. each, and the following results were measured at the above-mentioned time.

Glass No. 7 approximately 45 minutes

Glass p * about 75 minutes

Glass Nos. 1 to 6 as glass compositions of the present invention exhibited almost the same meltability as Glass No. 7.

TABLE 1

Note) Glass Nos. 1 to 7 are glass compositions of the present invention.

P * is the glass composition of Unexamined-Japanese-Patent No. 40126 74.

TABLE 2

The individual glass compositions shown in Table 1 were spun using a tip nozzle plate attached to the furnace with a 400 orifice and a conventional silver cooling wheel to produce a glass fiber having an average diameter of 16 μ without causing deposition. . The lifetime of the silver wheel, which is the time required from the attachment of the cooling wheel to the change in the nozzle, was measured using each glass composition to obtain the following results.

Glass 1st to 77th 70-100 hours

P * glass 15-20 hours

E glass 150-200 hours

C glass 15-20 hours

As is apparent from the above results, in the case of P * glass and Cglass, the life of the cooling wheel is about 15 to 20 hours, and the cooling wheel cannot be used for actual glass fiber production. On the other hand, even if the glass composition of this invention contains P * glass and C glass like a large amount of alkali sources, a cooling wheel can be used for a long time.

The glass fiber manufactured in this way is used for various alkali resistance tests, as mentioned later.

(1) weight loss test

Each glass fiber having a length of 1 cm was treated with various alkali solutions under the following conditions and the weight loss thereof was measured. Treatment conditions are as follows.

(I) glass fibers were treated with 50% cement extract, which was filtered through a slurry of a mixture of Portland Cement: Water = 1: 10 overnight, and the resulting extract was diluted twice at 18C for 18 hours. Get

(II) Glass fibers were treated with synthetic cement solution (NaOH 0.88 g / l, KOH 3.45 g / l and Ca (OH ₂ ) 0.48 g / l) at 90 ° C. for 18 hours.

(III) The glass fibers were treated with Ca (OH) ₂ solution having a density of 0.48 g / l at 90 ° C. for 240 hours.

(IV) Glass fibers were treated with Ca (OH ₂ ) solution having a density of 0.48 g / l at 90 ° C. for 240 hours.

(V) Glass fibers were treated with the same 50% cement extract as used in (I) above at 64 ° C. for 96 hours.

(VI) Glass fibers were treated with a mixed solution of 0.088 g / l NaOH and 0.345 g / l KOH for 96 hours at 64 ° C.

(VII) The glass fibers were treated at 20 ° C. for 2 months with a cement extract obtained by overnight filtration of a slurry of a mixture of Portland Cement: Water = 1: 10.

This result is shown in Table 3.

TABLE 3

(2) the change in the strength of the strand after elapse of time

The glass fiber strands thus prepared were treated with the same cement extract as used in section (VI) described in Table 3 at 64 ° C. for the scheduled dates shown in Table 4, and the strength thereof was measured by JISR 3413. The results are shown in Table 4.

TABLE 4

(3) the change of strength of cement products reinforced with glass fiber after the passage of time

Cement products containing about 5% by weight of glass fibers are dried by air for one week after molding, and then treated with hot water for a predetermined date at 60 ° C (as shown in Table 5) or 80 ° C (as shown in Table 6). Flexural strength of the treated product was tested by JIS A 1408. The results are shown in Tables 5 and 6.

TABLE 5

TABLE 6

As is apparent from the above results, the glass composition of the present invention is excellent in meltability, can be easily cooled, and can be spun under almost the same conditions as glass. In addition, the glass fibers thus prepared are excellent in alkali resistance, have high strength, and can be used to reinforce cement products without deteriorating their strength after time.

Claims (1)

54 to 60% by weight of SiO ₄ , 13 to 16% by weight of ZrO ₂ , 12 to 15% by weight of Na ₂ O, 5.5 to 14% by weight of MnO and 7% by weight of CaO, and the total weight of MnO and CaO is 11 A glass composition having at least% by weight and a weight of MnO equal to or more than a weight of CaO.