JPS6186451A - Manufacture of alkali resistant glass fiber - Google Patents

Abstract

PURPOSE:To manufacture the titled glass fiber which is capable of spray molding, high in Young's modulus and excellent in affinity for cement by coating an aq. (modified) PVA soln. on the surface of the glass fiber and thereafter heat-treating it. CONSTITUTION:An aq. soln. contg. 1-20wt% (modified) PVA (e.g. polyvinyl formal) which is added with a silane coupling agent, a lubricant, a softening agent and a plasticizer or the like if necessary and has >=90mol% degree of saponification plus 300-2,600 polymerization degree is coated on the surface of glass fiber and heat-treated at 150-500 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing alkali-resistant glass fiber for reinforcing products having a highly alkaline matrix such as cement and silicate.

Glass compositions have a lower tensile strength than other organic and inorganic fibers, and also have a much higher elastic modulus than other organic and inorganic fibers.

It is currently widely used as a reinforcing material suitable for fiber-reinforced composite materials such as

However, when glass fiber is used as a reinforcing material for cement, etc., the cement matrix becomes strongly alkaline with a pH of 12 to 13 due to the saturated dissolved state of CaQ (OII), which is a component of cement. In order to show that, the strength of the fiber itself has significantly deteriorated.
It was not possible to take full advantage of its properties as a reinforcing material.

Therefore, in order to increase the alkali resistance of the glass composition, a glass composition containing high zirconia (Zr01) is used as the base material, and the surface of the glass fiber is treated with a lubricant that imparts alkali resistance or a hydration reaction of cement. Although methods such as coating with a substance that retards alkali resistance have been adopted, it has not been possible to impart complete alkali resistance (=j) to glass fibers.

Furthermore, in addition to glass fiber, Kevlar, polypropylene, Hinilon, etc. (T-weaving ↑5) are considered as reinforcing materials for cement because they are not susceptible to alkaline earth metal corrosion. Vinylon has recently been used because it is common and inexpensive.However, vinylon has a lower Young's modulus and lower heat resistance than glass fibers, and is difficult to cut into short fibers, so it is difficult to cut into short fibers, so it is difficult to cut into short fibers. It has the disadvantage of not being able to

The purpose of the present invention is to provide an inexpensive cement reinforcing fiber that can be spray molded, has a high Young's modulus, is nonflammable, has good affinity with cement, and is not susceptible to corrosion by alkali in cement, that is, an alkali-resistant glass. The object of the present invention is to provide a method for producing fibers.

The present invention relates to a technique for coating the surface of glass fibers with a resin having good alkali resistance. Although there are a relatively large number of resins with good alkali resistance, polyvinyl alcohol is well known as a resin that has good alkali resistance and hydrophilicity, and thus has good affinity with cement.

However, when glass fiber coated with polyvinyl alcohol is used as a reinforcing material for highly alkaline hydraulic substances such as cement and silicic acid, even if the polyvinyl alcohol film has excellent alkali resistance, it has low water resistance. Because it dissolves into water and inhibits the hardening of cement, etc., and because it easily swells in water, the surface of glass fibers is eroded by the swollen alkaline water, which is a major problem. Although there have been some cases of using polyvinyl alcohol as a component of a sizing agent that imparts alkalinity, it has been attempted to overcome the above problems and fully utilize the excellent alkali resistance of polyvinyl alcohol as a coating for glass fibers. There are no inventions that attempt to utilize it.

On the other hand, it is well known that polyvinyl alcohol decomposes at temperatures around 200°C, and it is generally believed that excessive heat treatment should be avoided when using polyvinyl alcohol. For this reason, when polyvinyl alcohol is used as a sizing agent for glass fibers, 10
It is customary to dry by heating to a temperature of 0-130°C.

- The inventors have conducted intensive research on the effects of polyvinyl alcohol moths and heat treatment temperature on the alkali resistance and water resistance of glass fibers coated with polyvinyl alcohol. When the polyvinyl alcohol film is applied and then heat treated at a high temperature of 150 to 500"C, the polyvinyl alcohol film becomes substantially insoluble in water, does not inhibit the hardening of cement, etc., and the glass coated with the film becomes The surprising fact has been discovered that the strength deterioration in the cementitious matrix of fibers is extremely small.

Possible reasons for this are as follows. It is well known that polyvinyl alcohol crystallizes when heated, but when a solution of polyvinyl alcohol is applied to the surface of glass fiber and then heat-treated at a high temperature of 150 to 500°C, crystals f [ , progresses to the limit,
Depending on the heat treatment conditions, dehydration and decomposition of polyvinyl alcohol as shown in the following formula may occur, for example.

(J1'1 According to the research conducted by the present inventors, these dehydration and thermal decompositions begin to occur around 170°C and rapidly progress when the temperature exceeds 200°C. When these dehydration and thermal decompositions occur,
Polyvinyl alcohol coatings have a lower tensile strength, but when polyvinyl alcohol is coated on the surface of glass fibers, no particular strength problem occurs because the glass fibers are responsible for the tensile strength. Rather, as dehydration and thermal decomposition occur, the hydrophilicity of the film decreases, and its dissolution and swelling in water is significantly suppressed.
It is considered that the favorable effect that the strength deterioration in the cementitious matrix of the glass fiber coated with the film is extremely small has appeared.

In the present invention, it is necessary to heat-treat the surface of the glass fiber at a temperature of rL1so~500'C, preferably 170~450''C, after coating the surface of the glass fiber with a solution of polyvinyl alcohol.

Any polyvinyl alcohol can be used as long as it is water-soluble, but preferably it is polyvinyl alcohol with a density of 90 mol % or more and a degree of polymerization of 300 to 2,600.

- In the first invention, it is also possible to use modified polyvinyl alcohol instead of (1) vinyl alcohol. Modified polyvinyl alcohols include derivatives of polyvinyl alcohol such as polyvinyl formal and polyvinyl butyral, saponified products of copolymers whose main component is vinyl acetate such as ethylene polyvinyl alcohol, silyl-modified polyvinyl alcohol, and ethylene polyvinyl formal. Any derivative thereof can be used, but water-soluble ones are preferred.

The concentration of polyvinyl alcohol or modified polyvinyl alcohol in the solution is preferably 1 to 20%.

Since the polyvinyl alcohol film in the present invention is heat-treated at a higher temperature than when used as a normal sizing agent for glass fibers, the film tends to deteriorate. Therefore, in addition to polyvinyl alcohol, substances that maintain good thread quality, such as silane coupling agents, lubricants, softeners,
It is preferable to contain a solution or emulsion of a plasticizer and a substance capable of forming a film in order to obtain a glass fiber with good workability.

It can also contain acidic substances such as sulfuric acid, boric acid, ammonium chloride, etc., and has methylolmerase ability.

Possible methods for applying the polyvinyl alcohol solution to the glass fibers include, for example, applying the solution using an applicator during spinning of the glass fibers, or immersing the glass fibers in the polyvinyl alcohol solution after spinning.

The heat treatment in the present invention is carried out after winding the glass fiber coated with polyvinyl alcohol solution into a cake.
500℃ preferably 170 - +5o'c (7)
It can be applied by passing it through a furnace kept at a constant temperature, or by blowing hot air heated to a temperature of the same temperature. If the heat treatment temperature is lower than 150° C., the water resistance of the polyvinyl alcohol film is insufficient, and therefore a satisfactory glass fiber for reinforcing cement cannot be obtained. Furthermore, if the heat treatment temperature is higher than 500'C, the tensile strength of the glass fiber itself decreases, making it useless as a reinforcing material. In the present invention, it is also possible to irradiate with ultraviolet rays, infrared rays, radiation, etc. before or after heat treatment.

There are no particular limitations on the glass fibers used in the present invention, but preferably zirconia-containing glass fibers with excellent alkali resistance, more preferably 5% by weight of zirconia.
Glass fibers containing the above are suitable.

The present invention will be explained below using examples, but the present invention is not limited thereto.

Example 1 Samples 1 to 6 of glass were prepared with a filament diameter of 1a5/I.
, so that one strand consists of 200 filaments. Prepared soap ([J[a5
Mol% polyvinyl alcohol (NL-05, Nippon Gosei Kagaku) 15% by weight and silane coupling agent (A-1100, Union Carbide) 0.5% by weight
An aqueous solution containing is heated to 70°C, applied with an applicator during spinning, and wound into a paper tube. The undried cake strands were taken out of the incubator, air-dried, and then heat-treated at 200° C. for 5 minutes. The heat-treated strand was cut into a length of 5 cJn, and ordinary portland cement paste was applied to the periphery of the strand within an area of about lα, and the tensile strength was measured after keeping it in steam at 80°C (relative humidity 100%). and measured how it changed over time. The results are shown in Table 1. Note that the processing heat refers to strands that were simply treated with a normal vinyl acetate-based sizing agent and dried. Further, in the glass composition in the table, RO indicates an alkaline earth metal quantified product, and RtO indicates an alkali metal oxide.

The results shown in Table 1 show that the samples treated according to the present invention have much better alkali resistance than the untreated samples.

Example 2 Ft% 5i0260%, R,020%, Zr012
Glass consisting of 0% filament diameter 1 & 57.1
The book strand is spun to consist of 200 filaments. During spinning, water is used instead of the usual sizing agent to confine the yarn and wind it into a paper tube. A strand of 1 m is taken out from the rolled cake, dipped in the solution shown in Table 2, air-dried, rolled into a ring shape with a diameter of about 10σ, and preset at each temperature from 130°C to 600°C. The fibers were placed in an electric furnace and heat-treated for a period of 3 seconds to 10 hours, and the strength of the fibers was evaluated in the same manner as in Example 1, and water resistance was also investigated. The results are shown in Table 3.

As shown in Table 2 and Table 3, the samples (A8-17) heat-treated at a temperature of 150-500°C have better alkali resistance than the sample (7f17) heat-treated at a temperature lower than 150'C. In addition, the sample (A18) heat-treated at a temperature higher than 500°C has clear alkali resistance, but it can be seen that the strength of the glass fiber itself has decreased. Also from this table, it is clear that temperatures above 150°C, especially 1
? It can be seen that water resistance is significantly improved by heat treatment at O'C or higher. Furthermore, for all these samples,
Using a Fourier transform infrared spectrophotometer (FT-KR),
When we investigated the difference spectrum from the air-dried product without heat treatment, we found that
In the samples heat-treated at 170"C or higher (%9 to 18), it was observed that carbonyl groups and methyl groups were generated. This indicates that the thermal decomposition reaction of equation (2) described above is occurring. This is considered to indicate that.

Example 3 A strand of 1 m was taken out from the glass fiber cake of the water damage bundle used in Example 2, and polyvinyl fibers with different degrees of saponification or polymerization as shown in Table 4 were prepared. After immersing Recole Oyobi cation X in an aqueous solution containing hollyhinyl alcohol and cation X in a stratified ratio of 20:1, air drying,
Example 1 for those heat-treated at 200'C for 5 minutes
The strength of the fibers was measured using the same method. The results are shown in Table 4.

Table 4 All of the samples in Table 4 fall within the scope of the present invention (1) and all exhibit excellent alkali resistance.

μ Example A strand of 1 m was taken out from the water-focused glass TA fiber cake used in Example 2, immersed in a solution of modified polyvinyl alcohol shown in Table 5, heated at 130°C and
The strength of the fibers heat-treated at 00C for 30 minutes was measured in the same manner as in Example 1.

The results are shown in Table 5.

Otori Ding Marin 45 liters of clothing: 1 fruit, polyvinyl alcohol σ) KIS
zlj body, copolymerization mainly composed of MuF1-LZ hinyl <4' saponified product or its σ),,,・(7 bodies qv)
9 polyvinyl alcohol I river) 11, but not 9
If you use 5 blunt tools of force 7, treatment j and d, you will get 1 (with alkaline L)
1. It's a big deal (I can't change my blindness to 4).

Real response □j 5 Real 111Il force 2 Ha, water ULa uf. Glass size, 1.1≦4M (1) Strand t1m from cake
Take out the head and show Table 6 for each. i= tD water i+
) ffit &'- b2 71, L :'j, L
it', '+5 L,, for 5 minutes at 200°C, 1.7:
:+1. , strong winds were measured. It should be noted that all the degrees of risk in the table are IJ award-h (MQ%).

J'A. Although all of the samples in Table 6 are within the scope of the present invention, the amount of the substance added to the polyvinyl alcohol solution to maintain good thread quality is preferably determined from the viewpoint of thread quality or alkali resistance. , 0.0 per part by weight of polyvinyl alcohol
It is preferable to use it in a range of 0.01 to 1 part by weight.

Example 6 A strand of 1 m was taken out from the water-focused glass fiber cake used in Example 2, immersed in various aqueous solutions shown in Table 7, air-dried, and heat-treated at 200'C for 5 minutes. The strength of the fibers was measured using the same method as in Example 1.

All of the samples listed in Table 7 of Kite Eihaku have improved alkali resistance, especially strength retention, by containing water resistance-imparting substances within the scope of the present invention, such as polyvinylalfuric acid, methylol compounds, and organometallic compounds. It can be seen that the rate increases.

Example? Sixteen water-focused glass fiber cakes used in Example 2 were lined up and immersed in the solutions listed in Table 2 of Example 2 while releasing the cakes at a speed of 10 m/min, then heated to 270'C. The cut portion was passed through an electric furnace with a length of 15 m, and then wound up with a roving winder to make roving. GRC using this roving by spraying method.
was molded and a strength test was conducted. The force I length of the glass fiber was 25#JI, and the glass fiber content was 5% by weight.

Mortar is Portland cement (weight ratio) 1.00,
No. 5 silica sand α60, expanded cement (Denka OSA #2
0, electrochemical) 0.06, water reducing agent (Ma・fti 150
, Kao Soap) 0.00? , water α38.

When glass fibers and mortar were simultaneously sprayed onto the mold surface so that the GRC thickness was 1Q mm, the cuttability of the glass fibers, moldability, and conformability to the mold were all good. In particular, with regard to mold conformability, the behavior was significantly worse than that of glass fibers coated with conventional vinyl acetate-based sizing agents.

After molding, the sheet is cured, and the next day it is demolded and heated to 20°C.
The material was cured in water until it was 28 days old, and its bending strength was measured to be 295 kgf/cm. After immersing the sample cured for 28 days in hot water at 80℃ for 12 days, GR
When the bending strength of O was measured, it was 254 kgf/cj
It was hot.

Patent applicant: Jun Nagasaki, representative of Nippon Electric Glass Co., Ltd. - Procedural correct reading (method) % formula % 2 Title of invention Method for manufacturing alkali-resistant glass fiber 3 Relationship to the case of the person making the amendment Patent applicant address Shiga Prefecture 2-7-1-4 Seiran, Otsu City Date of amendment order 6 Table 5 on page 17 of the detailed statement of amendment shall be as per the attached sheet.

Procedural amendment May 28, 1985

Claims (2)

[Claims] (1) After applying a solution of polyvinyl alcohol or modified polyvinyl alcohol to the surface of glass fiber,
A method for producing alkali-resistant glass fiber, characterized by heat treatment at a temperature of 0 to 500°C. (2) The method for producing alkali-resistant glass fibers according to claim 1, wherein the modified polyvinyl alcohol is a derivative of polyvinyl alcohol, a saponified product of a copolymer containing vinyl acetate as a main component, or a derivative thereof.