JP2003002684A - Glass chopped strand - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a glass chopped strand which is easily fibrillated in cement slurry in spite of an alkali-resisting glass and hardly frozen even when air temperature drops to 0 deg.C or below. SOLUTION: The glass chopped strand comprises a glass fiber containing 0.5 mass% or below of water and 14 mass% or above of ZrO2 , which is prepared by applying greige goods containing a polyvinylpyrrolidone having a molecular weight of 3000 or higher.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a glass chopped strand suitable as a reinforcing material for cement-based materials used in the fields of construction and civil engineering.

[0002]

2. Description of the Related Art In the manufacturing process of glass chopped strands, a sizing agent is applied to a glass filament (glass single fiber) obtained by spinning molten glass from a bushing having hundreds to thousands of nozzles using an applicator. After that, these are aligned, a spinning step of making a cake by winding on a paper tube, a cake is dried, a drying step of forming a film of a sizing agent on the surface of the glass fiber, a cake is cut while unraveling, It consists of processing steps to produce glass chopped strands.

[0003]

When chopped strands made of alkali-resistant glass fiber are used as a reinforcing material for cementitious materials, the alkali resistance is excellent.
Although a sufficient reinforcing effect can be obtained for a long period of time, since the alkali resistant glass fiber contains a large amount of alkali component, it is easy to elute the alkali component, and it is used as a film former of a general alkali resistant glass fiber sizing agent. The polyvinyl acetate resin or acrylic resin may react with the alkaline component to form a strong film on the glass fiber surface. When such a film is formed, the bond between the glass filaments becomes strong, and even when the cement slurry is stirred, the glass chopped strands are difficult to be defibrated, and the defibrated state is unfavorable especially when the stirring time is short. There is a problem that it becomes uniform and a sufficient reinforcing effect cannot be obtained.

Further, the wet chopped strands cut from the cake that does not pass through the drying step contain a large amount of water (specifically, about 7% by mass), and therefore have excellent defibration property in the cement slurry. However, when the temperature falls below 0 ° C., it freezes and cannot be added to the cement slurry, or it is difficult to disintegrate in the cement slurry.

The present invention has been made in view of the above-mentioned circumstances, and even alkali-resistant glass is easily defibrated in cement slurry, and it is difficult to freeze even when the temperature is below 0 ° C. The purpose is to provide chopped strands.

[0006]

The glass chopped strand of the present invention has a water content of 0.5% by mass or less, and Z
made of glass fiber containing 14% by mass or more of rO ₂ ,
It is characterized in that a sizing agent containing polyvinylpyrrolidone having a molecular weight of 3000 or more is applied.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The glass chopped strands of the present invention are composed of glass fibers having a water content of 0.5% by mass or less, and therefore, are hard to freeze even when the temperature is 0 ° C. or less, and the glass chopped strands can be used in a cement slurry. Can be easily disentangled. By the way,
The water content of the glass chopped strands is lowered by reducing the amount of cooling water sprayed at the time of glass fiber spinning and the amount of water applied from the sizing agent, and by aging the cake and increasing the drying time or increasing the drying temperature. can do. In particular, when the cake is dried at 130 ° C. or higher for 10 hours or longer, the water content of the glass chopped strands tends to be 0.5% or lower. The method for measuring the water content of the glass chopped strand is JIS R3.
Based on 420.

Since the glass chopped strand of the present invention is made of glass fiber containing 14% by mass or more of ZrO ₂ , it has excellent alkali resistance, and even when it is used as a reinforcing material for a cement-based material, it is a cement-based material. Since the glass fiber is less likely to be eroded by the alkaline substance therein and the tensile strength of the glass fiber is less likely to be deteriorated, the reinforcing effect can be maintained for a long period of time.

The specific composition of the alkali-resistant glass fiber suitable for the present invention is, in mass%, SiO ₂ 54 to 65%, Zr.
_{O 2 14~25%, Li 2 O} 0~5%, Na 2 O 1
0 to 17%, K ₂ O 0 to 8%, RO (where R is
(Representing Mg, Ca, Sr, Ba, Zn) 0-10%,
TiO ₂ 0 to 7%, Al ₂ O ₃ 0 to 2%, more preferably, by mass%, SiO ₂ 57 to 64%, Zr.
_{O 2 18~24%, Li 2 O} 0.5~3%, Na 2 O
11-15%, K ₂ O 1-5%, RO (however, R
Represents Mg, Ca, Sr, Ba, Zn) 0.2 to 8
%, TiO ₂ 0.5 to 5%, and Al ₂ O ₃ 0 to 1%.

Since the glass chopped strand of the present invention is coated with a sizing agent containing polyvinylpyrrolidone having a molecular weight of 3000 or more as a film former, even if it is an alkali resistant glass fiber, it is unwound in the cement slurry. Excellent in fineness. That is, the molecular weight is 300
This is because a polyvinylpyrrolidone of 0 or more does not easily react with the alkaline component eluted from the alkali-resistant glass fiber, so that the film formed on the surface of the glass fiber does not become too hard and the bonding between the glass filaments does not become too strong.

The content of polyvinylpyrrolidone having a molecular weight of 3,000 or more is preferably 1.
It is 0 to 10% by mass, more preferably 1.5 to 8% by mass. When it is more than 10% by mass, the cohesiveness of the glass chopped strands is deteriorated and the glass chopped strands are fluffed before being put into the cement slurry, resulting in poor defibration property and less than 1.0% by mass. And the above effects cannot be expected.

The sizing agent used in the present invention is preferably a silane coupling agent such as aminosilane, epoxysilane, methacrylsilane, vinylsilane, ureidosilane, etc. in terms of solid content, preferably 0.05 to 1.0% by mass, more preferably 0.1 to 0.5 mass% is contained. That is, when the amount of the silane coupling agent is less than 0.05% by mass, the effect of preventing breakage of the glass fiber is low, and when it is more than 1.0% by mass, the defibration property of the glass chopped strands in the cement slurry is deteriorated. Is.

The sizing agent of the present invention contains a polyamine-based activator such as a polyalkyl polyamine alkyl amide derivative in an amount of preferably 0.01 to 0.5% by mass, more preferably 0.03 to 0, in terms of solid content. If the content is 0.3% by mass, the unwinding property of the glass fiber is improved. That is, when the content of the polyamine-based activator is more than 0.5% by mass, the glass fiber becomes sticky and gum up is apt to occur.
This is because if it is less than 01% by mass, it is difficult to improve the unwinding property of the glass fiber. By the way, gum up is that the sizing agent attached to the surface of the glass fiber is attached by friction to the contact parts of various jigs used in the processing step, and if this swells, it causes the cutting of the glass fiber. Becomes

Further, the sizing agent of the present invention preferably contains a polyvinyl acetate resin in an amount of 0.5 to 3.0% by mass in terms of solid content because the workability of chopped strands is improved.

The adhesion rate of the sizing agent of the present invention is 0.2-1.
5% by weight is suitable. That is, when the attachment rate of the sizing agent is less than 0.2% by mass, the surface of the glass fiber is prevented from being scratched, the binding property to the glass strand is imparted, the occurrence of fluff in the processing step is suppressed, the yarn is prevented from breaking, and the cement slurry is used. This is because the effect of improving dispersibility in the cement slurry due to the improvement of the defibration property becomes poor, and if it is more than 1.5% by mass, the product cost increases. Incidentally, the attachment rate of the sizing agent can be adjusted by changing the solid content of the sizing agent and the number of rotations of the applicator in the spinning step, and the measuring method is based on JIS R3420.

[0016]

EXAMPLES The glass chopped strands of the present invention will be described in detail below with reference to examples.

Table 1 shows examples (Sample Nos. 1 to 4) and comparative examples (Sample N) of the glass chopped strands of the present invention.
o. 5 to 7).

[0018]

[Table 1]

No. in the table Each sample of 1 to 7 was manufactured as follows.

First, in mass%, SiO ₂ 61%, Zr
O ₂ 19.5%, Li ₂ O 1.5%, Na ₂ O 1
2.3%, K ₂ O 2.6%, CaO 0.5%, Ti
After applying the sizing agent shown in Table 1 to an alkali resistant glass single fiber (diameter 18 μm) having a composition of O ₂ 2.6% by using an applicator so as to have a desired adhesion rate,
A cake was prepared by aligning 2000 of these and winding them up on a paper tube. Then, this cake 130
After drying at 10 ° C. for 10 hours, the cake was unwound and cut to obtain 13 mm glass chopped strands. Sample No. Since No. 7 was not dried, the water content was 7% by mass.

Polyvinylpyrrolidone having a molecular weight of 50,000 was produced by using PVP K-30 manufactured by ISPE Co., Ltd., and polyvinylpyrrolidone having a molecular weight of 1,000 or 5,000 was produced by changing the degree of polymerization.

The defibration property of glass chopped strands is
After mixing 3% by mass of glass chopped strands into a cement slurry consisting of 100 parts by mass of cement and 40 parts by mass of water, the mixture is put into a stirrer and stirred at a speed of 400 rpm, and the glass chopped strands are completely defibrated visually. Was measured and evaluated.

The freezeability of the glass chopped strands was visually evaluated after the glass chopped strands were kept at -10 ° C for 24 hours, and those not frozen were marked with "○", and those frozen were marked with "x". did.

As is apparent from the table, the N
o. Each of the samples 1 to 4 did not freeze, and the defibration time was as short as 30 seconds or less, and the defibration property was excellent.

On the other hand, No. Sample No. 5 used polyvinylpyrrolidone having a molecular weight of 1000, and thus had a long defibration time of 90 seconds. In addition, No. In the sample of No. 6, since polyvinylpyrrolidone was used as the sizing agent instead of the acrylic resin, the glass filaments were strongly bonded to each other, and the glass chopped strands could not be disentangled even after stirring for 10 minutes. Also, N
o. Sample No. 7 had a high water content of 7% by mass, and thus was frozen.

[0026]

As described above, the glass chopped strand of the present invention, even when using alkali resistant glass fiber,
The alkali component in the glass does not react with the sizing agent, the bonds between the glass filaments do not become too strong, and they easily defibrate in the cement slurry and do not freeze easily, so the glass chopped strands are defibrated especially in the cement slurry. It is suitable as a reinforcing material for cement-based materials produced by the above method.

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Claims (2)

[Claims] 1. A water content of 0.5% by mass or less, Z
made of glass fiber containing 14% by mass or more of rO ₂ ,
A glass chopped strand obtained by applying a sizing agent containing polyvinylpyrrolidone having a molecular weight of 3000 or more. 2. The sizing agent is polyvinylpyrrolidone having a molecular weight of 3,000 or more in a solid content display of 1.0 to 1
0.0 mass%, silane coupling agent 0.05 to 1.
The glass chopped strand according to claim 1, which contains 0% by mass and 0.01 to 0.5% by mass of a polyamine-based activator.