JPH02243543A - Glass fiber, production and use thereof - Google Patents

Abstract

PURPOSE:To improve the autoclave resistance of an alkali-resistant glass fiber chopped strand containing ZrO2 coating the strand with a thermoplastic resin by a suspension polymerization method. CONSTITUTION:100pts.wt. of a monomer such as styrene or vinyl chloride forming a thermoplastic resin such as PS or PVC is compounded with 5-800pts. wt. of glass fiber chopped strands prepared by cutting a strand comprising 10-800 filaments each having a diameter of <=24mum and containing >=10mol% of ZrO2, 100-3,000pts.wt. of an aqueous medium, 0.1-5pts.wt. of a suspension stabilizer of PVA and 0.005-3pts.wt. of a radical-generating polymerization initiator such as benzoyl peroxide, followed by suspension-polymerizing the mixture at approximately 80 deg.C. The reaction product is subsequently separated from water, washed with water and dried to provide an alkali-resistant glass fiber chopped strand. 100pts.wt. of an inorganic matrix such as cement mortar is blended with 0.5-15pts.wt. of the chopped strand and subsequently molded to provide a molding product having a high strength.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides alkali-resistant glass fibers with alkali-resistant,
Alkali-resistant glass fibers with excellent mechanical properties and autoclave resistance coated with a large amount of heat-resistant resin, methods for producing the same, and inorganic matrices reinforced with the alkali-resistant glass fibers (especially cement, cement, etc.) mortar, calcium silicate, etc.).

(The problem to be solved by the prior art/invention!!M) Since alkali-resistant glass fibers are difficult to be eroded by alkaline solutions, they cannot be easily eroded by inorganic matrices that contain or generate alkaline components [especially cement, cement mortar, calcium silicate, etc.]
It is used as a reinforcing material. The alkali resistance of alkali-resistant glass fibers is mostly determined by the content of the component ZrO in the glass composition, but it is also influenced by the type and amount of organic polymer (hereinafter also referred to as a sizing agent) applied to the fiber surface. Therefore, the type and amount of sizing agent applied are important factors in improving the alkali resistance of alkali-resistant glass fibers. When determining the sizing agent composition,
The polymer raw material used must not only have alkali resistance, but also satisfy spinnability, processing workability, and workability when producing a reinforcing body using the alkali-resistant glass fiber. The degree of cohesiveness required of alkali-resistant glass fibers differs depending on the forming method. For example, the papermaking method produces a soft type that is easy to defibrate in water, the brimix method produces a highly focused hard type that is difficult to defibrate during mixing, and the extrusion molding method, which is kneaded under stricter conditions than the brimix method, produces an ultra-highly focused type. Alkali-resistant glass fiber is required. Conventional hard-type chimachi whelk has insufficient cohesiveness, so if the mixing time is prolonged in the brimix method, it will defibrate into a ball shape, and if used in the extrusion molding method, it will cause problems with the extruder. The problem is that the screws are damaged by the shearing force of the screws and are broken into pieces, so that the reinforcing effect of the inorganic matrix is not achieved.

Generally, when producing secondary cement products, hardening of cement is accelerated in high-temperature steam in order to shorten demolding time and speed up mold rotation, or for early shipment. When producing calcium silicate products, autoclaving is also performed to generate tobermorite crystals or xonotrite crystals through a hydrothermal reaction. When manufacturing tobermorite-based calcium silicate plates, alkali-resistant glass fibers are added to the prepared raw materials and heated at 95°C for about 2 hours to perform a gelation reaction, followed by autoclaving at 180°C. Since it is carried out, the sizing agent must be insoluble in hot alkali.

However, the strength of conventional alkali-resistant glass fibers decreases due to heat treatment such as autoclave treatment.

Therefore, it has been considered to carry out the autoclave treatment at a low temperature, but if the autoclave temperature is lowered, there is a problem that the strength of the matrix decreases due to insufficient calcium silicate crystal growth.

On the other hand, as asbestos regulations have recently become stricter, alkali-resistant glass fibers are being reconsidered for applications where it was previously considered difficult to use them.
There is a growing demand for improved performance of alkali-resistant glass fibers.

The purpose of the present invention is to improve workability when molding inorganic matrices such as cement products and silica products reinforced with alkali-resistant glass fibers, and to have excellent mechanical properties, alkali-resistant properties, and autoclave-resistant properties. The purpose of this invention is to provide alkali-resistant glass fibers that are resistant to alkali.

Another object of the present invention is to provide a method for producing the alkali-resistant glass fiber.

Yet another object of the present invention is to provide an inorganic matrix reinforced with the alkali-resistant glass fibers.

In order to achieve the above object, the present inventors have conducted various studies and have found that when ultra-highly focused chopped strands are manufactured by applying a thermoplastic resin to alkali-resistant glass fibers using a suspension polymerization method, It has been found that the alkali resistance properties of the reinforcing body are improved, and when an inorganic matrix such as cement, cement mortar, calcium silicate, etc. is reinforced with the glass fiber thus obtained, the performance of the reinforced body is significantly improved.

More specifically, the present inventors have obtained the following new findings.

Conventionally, the amount of sizing agent applied to glass fiber during the spinning process is at most about 3% (by weight), which is about 0.2μ in terms of film thickness.
Met. However, due to the thin film thickness, the alkali-resistant glass fibers were damaged during molding of cement products, calcium silicate products, etc., or were eroded by alkali during high-temperature curing, making it impossible to exhibit sufficient reinforcement and hardening. As a method for applying a large amount of sizing agent to the fibers, there is a two-stage coating method in which the spun yarn is dried and then a highly concentrated sizing agent is applied again. However, in the two-stage coating method, the sizing agent was applied only around the strand and did not penetrate into the strand.

On the other hand, in chopped strands produced by suspension polymerization, a predetermined amount of organic polymer in the range of 5 to 40% by weight is uniformly and thickly applied to the filaments inside the strand. Therefore, the surface of the alkali-resistant glass fibers blended into the reinforcing body is less likely to be scratched, and the alkali-resistant glass fibers are less likely to be eroded by the alkali in the inorganic matrix even during high temperature curing.

The present inventors applied a thermoplastic resin to chopped strands of alkali-resistant glass fiber using a suspension polymerization method, and found that
It has been found that ultra-highly bundled alkali-resistant glass fiber titanium butotstrands can be produced with any number of bundled fibers from 0 to 800. According to the experiments conducted by the present inventor, as is clear from the experimental results shown in Figure 1, it was found that the bending strength of the reinforcing body increases when the number of bundled filaments in the strand is reduced. However, with conventional spinning technology, mass production is difficult. From the point, the limit was about 50 pieces.The present inventors made a bundle of 50 to 50 pieces using the suspension polymerization method.
When a reinforcing body was manufactured by mixing 800 chopped alkali-resistant glass fiber strands with cement mortar and a matrix of calcium silicate, it was found that mixing workability, alkali resistance properties, and autoclave resistance properties were significantly improved. That is, since the chopped strands have ultra-high focus, even when vigorously stirred and mixed together with the matrix, the strands did not unravel and the fibers did not break. Furthermore, since a large amount of heat-resistant and alkali-resistant resin was coated on the surface of the alkali-resistant glass fibers, even when the reinforcing body was cured at high temperatures, the decrease in strength was very small.

Means for Solving CRB] The present invention has been completed based on the above new findings, and has the following gist (1) to (3).

(1) Alkali-resistant glass fiber containing zirconium oxide An alkali-resistant glass fiber characterized in that it is made by coating titanium butotstrands with a thermoplastic resin using a suspension polymerization method.

(2) A method for producing alkali-resistant glass fibers, which comprises coating chopped strands of alkali-resistant glass fibers containing zirconium oxide with a thermoplastic resin by a suspension polymerization method.

(3) An inorganic matrix comprising chopped strands of alkali-resistant glass fibers containing zirconium oxide and reinforced with alkali-resistant glass fibers formed by coating them with a thermoplastic resin using a suspension polymerization method.

In the present invention, the alkali-resistant chopped glass fiber strands are not particularly limited as long as the purpose of the present invention can be achieved. However, since the alkali-resistant glass fiber according to the present invention is used in combination with an inorganic matrix such as cement mortar that contains or generates an alkali component, the glass fiber as a material must have alkali resistance. In particular, Zr0z-containing alkali-resistant glass fiber having an alkaline solubility of 4% or less is a suitable material. Here, the alkali solubility means 2g of glass fiber with a fiber diameter of 13±0.2μ at 10% at 95°C.
This figure shows the degree of weight loss of glass fibers as a percentage when immersed in 100 g of sodium hydroxide aqueous solution for 1 hour.

As the alkali-resistant glass fiber that can be used in the present invention, at least ZrO! The glass fiber in the present invention generally contains 5 mol% or more of
r0z is 10 mol% or more, preferably 11 mol% or more,
Particularly preferably, the content is 11.5 mol% or more. Examples of glass fibers that satisfy the above conditions include, in terms of mol%, Sin: 50 to 76%, Zr0z: 8 to 1
6%, R,0:10~25%, R'o:o~10%,
CaFx: 0-2%, BzOs: 0-7%, PtOs:
It is a glass fiber consisting of 0 to 5%, Sn02: O to 7.5%, and other metal oxides: 0 to 10%.

In the above composition, R represents an alkali metal, R' represents an alkaline earth metal, Zn or Mn, and other metal oxides are A
ItOs, FexOx, TiOx, C
eOx, Lago2, NdxOs, Prh
O++, etc. (Hereinafter, each symbol and definition has the same meaning unless otherwise specified).

The alkali-resistant chopped glass fiber strand is usually a bundle of 50 to 800 pieces having a diameter of 24 μm or less, and its length is usually 3 to 25 Ilal.

The thermoplastic resin for coating the chopped alkali-resistant glass fiber strands in the present invention is not particularly limited as long as the chopped alkali-resistant glass fiber strands can be bundled by suspension polymerization. For this purpose, materials with good alkali resistance are used. Specific examples of such thermoplastic resins include polystyrene, polyacrylonitrile, polymethyl acrylate, polyvinyl chloride, polyvinyl acetate, and the like.

In the present invention, the inorganic matrix to be reinforced with alkali-resistant glass fibers is not particularly limited as long as it is a carbon-free compound or a carbon compound other than an organic compound, but in light of the purpose of the present invention, It is preferable that the alkali-resistant glass fiber of the present invention contains or generates an alkali component, and examples of such materials include cement, cement mortar, calcium silicate, etc. It can be obtained by carrying out suspension polymerization of the monomers by coexisting one or more of the monomers with the alkali-resistant glass fiber chopped strands in a suspension polymerization system. The alkali-resistant glass fiber chopped strands used at this time can be used as they are on the market, but if the Chimisaki Tsubu strands are wetted by soaking them in advance in the monomer used for polymerization, the resulting product can be obtained. is preferable because it is completely covered with each of the glass fiber filaments constituting the chopped strand.

During the polymerization, the alkali-resistant glass fiber chopped strands to be present in the polymerization system can be used at a ratio of 5 to 800 parts by weight per 100 parts by weight of the monomer, particularly when the ratio of the monomer to the glass fiber chopped strands is 100 parts by weight. :5
A range of 0 to 500 is particularly preferred. During suspension polymerization,
The ratio of the aqueous medium to the monomer is preferably 100 to 300 parts by weight per 100 parts by weight of the monomer. If less than 100 parts by weight of aqueous medium are used per 100 parts by weight of monomer, as the polymerization progresses, the overall product mixture will become very viscous, making it difficult to stir the product mixture and making it difficult to conduct heat or control the temperature. This tends to make it difficult to obtain a resin with uniform properties.

If the amount of the aqueous medium is 3000 parts by weight or more, the amount of monomer charged is inevitably limited and productivity is reduced, which is uneconomical.

Polymerization is carried out by the suspension polymerization method, and the suspension stabilizers that can be used at this time are those used when monomers are polymerized by the suspension polymerization method, such as various types of saponification of polyvinyl acetate! yJ (polyvinyl alcohol) styrene-
Examples include water-soluble polymer compounds such as maleic acid copolymer, HoIJ sodium methacrylate, and copolymer of ethylhexyl acrylate and acrylic acid, and these may be used alone or in combination of two or more types. You can also do it. Also,
These suspending agents and certain surfactants can also be used in combination. Furthermore, inorganic compounds such as calcium carbonate can also be used.

For the suspension polymerization reaction, a vertical reactor commonly used for suspension polymerization can be used.

In addition, it is preferable to use a polymerization initiator when polymerizing the monomers, and as such a polymerization initiator, a commonly used radical-generating polymerization initiator is preferable, and the amount used is determined according to the amount required to initiate the polymerization. Although it varies depending on the properties of the agent and the polymerization temperature, it is 0.005 to 3.0 per 100 parts by weight of monomer.
It can be used in parts by weight.

Reinforcement of the inorganic matrix with the alkali-resistant glass fibers of the present invention may be carried out by means known per se.

[Example/Experiment example]

The present invention will be explained in more detail below with reference to Examples and Experimental Examples, but the present invention is not limited thereto.

Examples 1 to 8 Alkali-resistant glass fiber chopped strands were blended with the following polymerization reactant composition, charged into a 3E autoclave, heated to 80°C in a constant temperature water bath with stirring, and polymerized for about 5 hours. The reaction was carried out. After the reaction was completed, the contents in the autoclave were taken out onto a wire mesh, water and the reactant were separated, washed with water, and then dried in an electric furnace. By this, Tables 1 to 3 respectively
The alkali-resistant glass fibers described in Examples 1 to 8 were manufactured.

Polymerization reaction product composition Alkali-resistant glass fiber: 150gr Styre 7 70gr Acrylate acrylate: 30gr Benzoyl peroxide: Igr Water: 1300gr Suspending agent
・ 0.7 g rExample 9・Test Example 1 (
Brimix molding method) Sand: Ordinary Portland cement (
S:C)-1: 1, Water: Ordinary Portland cement (
W:C) ==o, 4:1, water reducing agent: ordinary portland cement=0.01:1, mortar composition of the above composition, alkali-resistant glass fibers of Examples 1 to 4 in Table 1 and conventional product (NEC AC306H-3502 (manufactured by Glass Co., Ltd.) was added in an amount of 2.0% (by weight), mixed for 30 seconds using an omni mixer, and then poured into a wooden form (510 x 320 x 10 mm) to form a flat plate. After curing this in a constant temperature room at 20°C for 3 days, it was demolded to make a specimen of 250×50×IOm+a, and its bending strength was examined. In addition, convergence and autoclave resistance were also measured. The results are shown in Table 1.

The bending strength was determined by measuring the strength in water at 20°C for 28 days. In addition, as for convergence, the degree of defibration of the strands after stirring in mortar for 60 seconds was examined. Autoclave resistance was determined by examining the state of the strands after being treated in a Ca(OH)* saturated solution at 180''C for 10 hours.

As shown in Table 1, it can be seen that the alkali-resistant glass fibers of Examples 1 to 4 all have a higher adhesion rate of thermoplastic resin, better cohesiveness, and better autoclave resistance than conventional products. Although the product of Example 3 has low bending strength,
This is because the number of glass fibers in the strand was much larger than in the other examples, and the bonding area between the matrix and the glass fibers was small. It is thought that the reason why the product of Example 3 has particularly excellent autoclave resistance is that the adhesion rate of the thermoplastic resin is high.

Example 10/Test Example 2 (Extrusion molding method) S/C-1 W/C-0,8 Bulb/(SiC) =0.042 Alkali-resistant glass fiber/(SiC) =0.03 Conducted with the above formulation Mortar was made using the alkali-resistant glass fibers of Examples 1 to 4 and the conventional product (AC306H-350Z manufactured by Nippon Electric Glass Co., Ltd.), and an extruder (Mikami Kogyo (■) HT-
250) to form a flat plate of 1800 x 210 x 16 mm. After the molded product was naturally cured for 2 days, it was autoclaved at 160°C for 6 hours. 50X210X from molded product
A specimen for bending strength measurement with a size of 16 mm was prepared, and the bending strength was measured. In addition, fluidity during extrusion, dispersibility of alkali-resistant glass fibers, fibrillation properties, and fiber length were also measured. The results are shown in Table 2.

At that time, fluidity was measured by reading the die pressure of the extruder, dispersibility was measured by breaking the uncured molded product immediately after extrusion, and observing the dispersion state of fibers in the cross section, and fibrillation. The fiber length is measured by observing the bundled state of the fibers after mixing in a mixer and kneader, and the fiber length is determined by cutting out an approximately 11-square sample from the molded product, dissolving the matrix in hydrochloric acid (36%), and measuring the remaining fiber length. The length was measured using a microscope.

As shown in Table 2, the products of Examples 1 to 4 have excellent fluidity and dispersibility, and therefore are excellent in workability. In addition, the fibers are difficult to break during molding, so the bending strength is high. However, Example 3
The bending strength is small, similar to the data for the Brimix method. This is considered to be because the strands were not defibrated in the extruder due to large adhesion, and the adhesion area with the matrix was smaller than in other examples.

Example 11/Test Example 3 (calcium silicate plate) Cement 2
60 parts, SiO□; 40 parts, bentonite: 10 parts,
The alkali-resistant glass fibers of Examples 5 to 8 and the conventional product (Nippon Electric Glass Co., Ltd. AC
306H-3502) was added, heated at 95°C for 2 hours to perform a gelation reaction, and the resulting slurry was cast into a mold and left at room temperature for 2 days, then autoclaved at 180°C for 12 hours. A calcium silicate plate was prepared by the above treatment. The bending strength and convergence rate (measured by the method described below) of the calcium silicate plate thus prepared were examined, and the results are shown in Table 3.

As is clear from Table 3, all of Examples 5 to 8 maintained focus in the hot alkaline solution.

1) Focusing rate: 1χNaOH500cc in 11 beakers
After heating to 95°C, 50 strands of alkali-resistant glass fiber were placed in the same solution, heated for 30 minutes, and stirred for 1 minute using a lab mixer to keep the strands completely swollen and soft. ratio.

Test Example 5 Using a conventional spinning method (Nippon Electric Glass Co., Ltd., E fiber, catalog), fiber length 6a+m, fiber diameter 13μ,
Focusing number: 25, 50, 100, 150, 200
2.0% (weight) of each was added to mortar with the same composition as in Test Example 1, and a sample was prepared under the same conditions as Test Example I.
The 8-day bending strength was measured to examine the relationship between the number of bundles and the bending strength. The results are shown in FIG.

It can be seen from FIG. 1 that as the number of bundled wires decreases, the bending strength increases.

〔Effect of the invention〕

Alkali-resistant glass fiber was developed as an asbestos alternative material.
Although it has been used as a building material and industrial material for about 15 years, it has not been used in some applications because of its lack of long-term durability or its strength due to autoclave-resistant treatment.

Since the present invention has significantly improved the autoclave resistance and alkali resistance of the alkali-resistant glass fibers and the workability during production of the inorganic matrix reinforced with the alkali-resistant glass fibers, it is expected that the invention will be used in a wider range of applications.

[Brief explanation of drawings]

FIG. 1 is a graph showing the results of investigating the relationship between the number of bundled strands and bending strength. Figure 1 Convergence number procedure Nefu official document (spontaneous)

Claims (3)

[Claims] (1) An alkali-resistant glass fiber characterized by being made by coating chopped strands of alkali-resistant glass fiber containing zirconium oxide with a thermoplastic resin using a suspension polymerization method. (2) A method for producing alkali-resistant glass fibers, which comprises coating chopped strands of alkali-resistant glass fibers containing zirconium oxide with a thermoplastic resin by a suspension polymerization method. (3) An inorganic matrix reinforced with the alkali-resistant glass fiber according to claim 1.