JPH10183473A - Bundled yarn - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a bundled yarn suitable for reinforcing a hydraulic material such as a cement or a concrete by bundling a plurality of fibers with a water-soluble polymeric resin. SOLUTION: This bundled yarn is obtained by doubling 5-10,000, preferably 10-3,000 polyvinyl alcoholic fibers having 0.1-10de, preferably 0.5-5 de single fiber size, dipping the resultant doubled fibers in an aqueous solution of a water- soluble polymeric resin such as an ammonium salt of an isobutylene-maleic anhydride copolymer, then squeezing the solution, subsequently drying the fibers under heating and then cutting the dried fibers to a prescribed length. The resultant bundled yarn has >=50% opening degree at pH12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bundled yarn suitable for reinforcing a matrix such as a hydraulic hardened material.

[0002]

2. Description of the Related Art Conventionally, for the purpose of improving performance such as bending strength and toughness and suppressing cracking, it has been known to blend a fibrous material into a matrix of a hydraulically hardened material such as concrete and cement mortar. Have been. However, it is extremely difficult to uniformly disperse the fibers in the matrix, and there is a problem that the fibers are entangled into a lump (fiber ball) during kneading, and the reinforcing effect is hardly exhibited.

[0003] From the above, it has been proposed to use a bundled yarn (chopped strand) in which a plurality of fibers are bound with a sizing agent as a reinforcing material. For example, a plurality of fibers are bundled with a water-soluble polymer resin. The bundled yarn is disclosed in JP-A-59-136.
No. 62, for example. When such a bundled yarn is used, it is first dispersed in a matrix in the form of a bundled yarn,
Next, since the bundled yarn is dissociated into single fibers and dispersed therein (because they are dispersed in two stages), a fiber ball having excellent dispersibility is formed as compared with a case where unbundled fibers are mixed. It has difficult features.

[0004]

However, in recent years,
Mixing of concrete or the like with reinforcing fibers is extremely short (for example, about 30 seconds to 1 minute), or water is necessary for dissolving the sizing agent in order to enhance the mechanical performance of the cured product. Application under various conditions, such as when using mortar with reduced mortar, has been studied, and a bundled yarn having more excellent dispersibility has been demanded. An object of the present invention is to provide a bundled yarn having a high reinforcing effect and further excellent dispersibility.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a bundled yarn in which a plurality of fibers are bundled with a water-soluble polymer resin,
12 is a bundled yarn having a degree of defibration of 50% or more.

[0006] The bundled yarn of the present invention can be used in various applications, but has a remarkable effect as a reinforcing fiber of a hydraulically cured product in which the matrix is subjected to an alkaline atmosphere. That is, when water reacts with concrete, mortar, or the like, the kneaded material becomes an alkaline atmosphere. Therefore, the bundled reinforcing yarn to be used must have excellent defibration properties even under alkaline conditions of pH 12.

[0007] If the degree of fibrillation at pH 12 is high, the mixture is easily fibrillated without the shear force generated when kneading the mixture, so that not only excellent matrix dispersibility can be obtained but also the kneading time can be shortened, and the shearing force can be further reduced. As a result, the fiber is hardly damaged, and the reinforcing effect is sufficiently exhibited. pH
The degree of defibration at 12 needs to be 50% or more,
Those having 0% or more, more preferably 70% or more, particularly 90% or more are more preferable. When used to reinforce hydraulically cured products,
The degree of defibration at pH 12 is an important parameter,
A higher degree of fibrillation at pH 12 has a more excellent effect. The fibrillation degree at pH 12 referred to in the present invention means that the bundled yarn cut to the length to be used is at 20 ° C.
When stirring is performed in alkaline water having a pH of 12, this refers to the percentage of single fibers that are defibrated within 5 minutes. In addition, the degree of defibration at pH 7 is preferably 40% or more, more preferably 50% or more, and particularly preferably 60% or more. Although the degree of defibration at pH 12 is an important parameter, those having a high degree of defibration at pH 7 are more preferable in terms of defibration properties and the like.

In order to obtain a bunched yarn having a high degree of fibrillation, it is necessary to use a water-soluble resin which has high solubility under alkaline conditions and dissolves in water to exhibit an anionic property. A water-soluble polymer resin having units is used. Examples of the sizing agent that can be used in the present invention include ammonium salts of isobutylene-maleic anhydride copolymer,
Salts (sodium salt, ammonium salt, etc.) of a copolymer of vinyl alcohol-based polymer with acrylic acid, methacrylic acid, maleic acid, phthalic acid, maleic anhydride, itaconic anhydride and the like can be mentioned. Among them, it is preferable to use a water-soluble resin composed of a polyvalent carboxylate. As the sizing agent, different kinds of resins may be used in combination. The sizing agent has a viscosity of 2 to 2 at 20 ° C and 4% by weight aqueous solution.
It is preferably 200 cps, especially 2 to 50 cps. Those having such a viscosity have a small effect on the hardening of the hydraulic material and the like, and also provide excellent effects in terms of solubility.

[0009] The concrete and the like react with water to form calcium hydroxide, potassium hydroxide, sodium hydroxide and the like, and the environment of the kneaded material becomes an alkaline atmosphere. Therefore, when a polyvinyl alcohol (PVA) -based water-soluble resin having a high degree of saponification is used, the degree of crystallinity is increased at the same time as the saponification and hydrophobicity of the PVA. , The solubility in water is reduced, and the defibration of the bundled yarn becomes insufficient. Also vinyl acetate
When an emulsion such as a copolymer of ethylene and a copolymer of vinyl acetate and acrylic acid is used, after the fibers are applied, the emulsion becomes a film and the solubility decreases. In this case, although the fiber is defibrated by the shearing force generated at the time of kneading with the matrix or the like, the excellent defibration property as in the present invention cannot be obtained.

The fibers constituting the bundle yarn are not particularly limited. For example, organic synthetic fibers such as PVA fiber, acrylic fiber, polyamide fiber, polyolefin fiber (polypropylene, polyethylene, etc.), and inorganic fibers such as glass fiber. Can be used. Among them, PVA-based fibers having high fiber strength and excellent adhesion to a hydraulic molded product are preferable.
From the viewpoint of dispersibility and reinforcement, the denier of the single fiber constituting the bundled yarn is preferably 0.1 to 10 d, particularly preferably 0.5 to 5 d, and the aspect ratio is 20 to 3000, particularly 40 to 9 d.
00, more preferably 150 to 400. According to the present invention, since the dispersibility in the matrix is remarkably improved, sufficient dispersibility and reinforcing properties can be obtained even when fibers having a large aspect ratio, which tends to decrease the dispersibility, are used. In addition, single fiber 5
It is preferred that 10,000, especially 10 to 3,000, yarns are drawn together to form a bundle. 100 to 1 for the bundled yarn as a whole
It is preferably about 00000d, especially about 200 to 5000d. In order to enhance the adhesiveness to the matrix, the fiber cross section may be flattened, the surface of the fiber may be uneven, or the fiber may be twisted as necessary.

The method of applying the water-soluble resin is not particularly limited, but a method in which long fibers are continuously sent from the beam creel and immersed in a tank containing a sizing agent, or -A method of attaching to a long fiber by a ratchet method, and then squeezing with a squeezing roll so as to maintain a constant amount of attachment.
At this time, it is preferable to attach the water-soluble resin as an aqueous solution dissolved in water, and it is preferable to use an aqueous solution of 30 to 300 g / liter, particularly about 50 to 200 g / liter. The amount of the sizing agent to be attached is 0.5 to 30% by weight of the fiber weight, and 1 to 1 in view of the sizing effect and the defibrating property.
It is preferably 0% by weight, especially 3-7% by weight.

After the aqueous solution is applied, it is preferable to carry out a drying treatment, preferably at about 80 to 200 ° C., particularly at 90 to 180 ° C.
It is preferable to dry to a degree. Further heat treatment can be performed to adjust the water solubility. The bundled tow may be cut to a predetermined length by a cutting machine or the like, but other methods may be adopted, and the bundled yarn is directly connected without temporarily winding the long fiber after spinning. It can also be manufactured.

The method for adding the bundled yarn of the present invention to a matrix is not particularly limited. Hereinafter, the case where the matrix is a hydraulic material such as cement mortar or concrete will be described as an example. A preferred method of adding the bunched yarn of the present invention is to put it in a matrix such as cement mortar or concrete to which water is not added, knead it sufficiently, then add water and defibrate by adding water. Is preferred from the viewpoint of fiber dispersibility. As the reaction between cement and water progresses, the slurry becomes alkaline and pH
However, excellent fibrillation and dispersibility can be obtained.

[0014] The addition rate of the bundled yarn in the light matrix is 0.1 to 10% by volume, particularly 0.2 to 8% by volume, and further preferably 0.5 to 5% by volume in terms of fiber dispersibility and reinforcing property. Is preferred. The sizing agent of the present invention has excellent performance as a reinforcing material for a substance (a hydraulic material) that cures in the presence of an appropriate amount of water. Representative cements such as Portland cement, blast furnace cement, silica cement, fly ash cement, alumina cement,
Gypsum, calcium silicate, magnesium carbonate, calcium carbonate, etc., may be used alone or in combination.
In addition, various aggregates can be used depending on the purpose, such as lightweight aggregates such as shirasu burn and perlite, pozzolan for improving dimensional stability, stone powder for imparting surface smoothness, silica powder and calcium carbonate powder. It can be mixed and used, and furthermore, a plasticizer such as methylcellulose, an AE agent, a fluidizing agent, a water reducing agent, a thickening agent, and a water retaining agent for imparting appropriate viscosity to improve moldability and shape retention. Agents and water repellents can be mixed and used.

The kneading machine used for the matrix in which the bundled yarn of the present invention is blended does not need to be a special one, and generally used tilting mixers, truck mixers, two-axis mixers, omni mixers, Kneading is possible with a pan mixer or the like. The molding method is not particularly limited, and it can be used in a pressure molding method, a vibration molding method, a combined vibration and pressure molding method, a stretch molding method, a papermaking molding method, a winding molding method, a vacuum molding method, and an extrusion molding method. It can also be used for spraying and plastering materials. Further, the bundled yarn of the present invention can be used in various fields as a reinforcing material for hydraulically cured products, and is particularly suitably used in the field of civil engineering and construction. Specific examples include cement tile, thick slates, corrugated slates, cement boards and their secondary products (concrete, mortar blocks, floor panels, wall panels, partitions, etc.). It can be widely used for building materials such as wood, interior materials, field boards, and exterior materials, as well as in the construction field such as steel frame foundations and wooden foundations, as well as noises such as partitioning materials for general roads, expressways and railways, and wall materials on both sides, and safety wall covering materials. .

[0016]

The present invention will be further described below with reference to examples. [Fibrillation degree at pH 7] 500 g of bundled yarn 1 g
The beaker was mixed with 500 cc of distilled water (20 ° C.), stirred at 150 rpm for 5 minutes using a stirring propeller, and the solution was filtered through a 40-mesh wire net to collect a fibrous material. Next, what was defibrated into single fibers and what had been bunched were visually separated with a tweezers to separate the defibrated and bunched ones, each was dried and the weight was measured, and the percentage of defibrated I sought. [Fibrillation degree at pH 12] 1 g of bundled yarn is 500 c
500 g of an aqueous solution containing 0.4 g / l of calcium hydroxide, 3.5 g / l of potassium hydroxide, and 0.9 g / l of sodium hydroxide in a beaker of c.
(20 ° C.) and 150 rpm using a stirring propeller.
The mixture was stirred at m for 5 minutes, and the solution was filtered through a 40-mesh wire net to collect fibrous materials. Next, what was defibrated into single fibers and what had been bunched were visually separated with a tweezers to separate the defibrated and bunched ones, each was dried and the weight was measured, and the percentage of defibrated I sought.

[Fibrillation degree after matrix kneading%] 2% by volume of bundled yarn, sand / portland cement ratio: 1/1, mixed in a dry state, water / cement ratio: 0.4 Water was added to mix the mixture for 30 seconds. After mixing on a 40-mesh wire net, 20 g of the paste is sampled and applied so as to have a uniform thickness, and the cement content is immediately applied to JIS A1103 (coarse aggregate test method).
The fibers were washed out based on the above, and the fibers were collected to prepare standard samples (A to E) of the degree of defibration.

A: Fibrillation degree 0 to 20% A state in which the bundled yarn is completely unfibrillated or a state in which a single fiber is slightly fibrillated from a part thereof B: Fibrillation degree 20 to 40% The number of single fibers is compared The number of monofilaments is relatively large, and the total denier number of bundled yarns is relatively reduced. C: Fibrillation degree 40-60% The number of single fibers is increased, and about half of the single fibers constituting the bundled yarns are fibrillated. D: degree of fibrillation 60-80% state in which more than half of bundled yarn is defibrated into single fibers E: degree of defibration 80-100% state in which most of bundled yarn is defibrated into single fibers A similar test was performed using the bundled yarn (sample), and the defibration state was evaluated by comparing with the sample. Note that ordinary Portland cement manufactured by Chichibu Onoda Cement Co., Ltd. was used as Portland cement.

[Bending strength kg / cm ² ] Using an Instron TT-CM, a centrally concentrated load of 10 cm in span was applied to create a stress-deflection curve, and the maximum bending stress in this curve was defined as the bending strength. [Viscosity cps] Aqueous solution of water-soluble resin (20 ° C, concentration 4
% By weight) and the B-type viscosity (Brookfield viscosity) was measured.

Example 1 Single fiber denier 1.8 denier
1 PVA-based fiber (5501 manufactured by Kuraray Co., Ltd.)
000 pieces were immersed in a 150 g / l aqueous solution of an ammonium salt of isobutylene-maleic anhydride copolymer (Isovan-110 manufactured by Kuraray Co., Ltd.) shown in Chemical formula 1, and then squeezed, and then squeezed at 100 ° C. After drying for 1 minute, it was cut to obtain a bundled yarn of 1800 denier and 6 mm in length (the resin adhesion amount was 5.5% by weight).

[0021]

Embedded image

Next, the obtained bundled yarn was 2% by volume, sand /
Inject so that the Portland cement ratio is 1/1,
After mixing in a dry state, water was added so that the water / cement ratio became 0.4 and mixing was performed for 30 seconds. This paste was poured into a mold having a thickness of 4 cm, a width of 4 cm, and a length of 16 cm, shaken, compacted, left at room temperature for 24 hours, removed from the mold and air-dried for 4 weeks (20 ° C. × 65% RH). Was done. Table 1 shows the results. The bundled yarn of the present invention has a high degree of defibration (that is, a high degree of defibration at pH 12 and pH 7) even under conditions where substantially no shearing force is applied to the fiber, and has a high defibration property, fiber dispersibility, and reinforcing property. It turns out that it is excellent.

Example 2 The same procedure as in Example 1 was carried out except that a sodium salt of an itaconic acid-modified polyvinyl alcohol-based polymer (KL-506 manufactured by Kuraray Co., Ltd.) was used as a sizing agent. Table 1 shows the results. [Comparative Example 1] As a sizing agent, a polymerization degree of 500 and a saponification degree of 8
The procedure was performed in the same manner as in Example 1 except that 8.5% of a polyvinyl alcohol-based polymer (PVA-205 manufactured by Kuraray Co., Ltd.) was used. Table 1 shows the results.

Comparative Example 2 The same procedure as in Example 1 was carried out except that an ethylene-vinyl acetate-vinyl chloride copolymer emulsion (Vinizol manufactured by Daido Kasei Kogyo Co., Ltd.) was used as a sizing agent. Table 1 shows the results. Comparative Example 3 A mortar cured product was produced in the same manner as in Example 1 except that no reinforcing fiber was used. Table 1 shows the results.

[0025]

[Table 1]

[0026]

According to the present invention, a bundled yarn having a high reinforcing effect and being more excellent in dispersibility, particularly a bundled yarn suitable for reinforcing a hydraulic cured product can be obtained.

[Brief description of the drawings]

FIG. 1 is a view showing a bending stress-deflection curve of molded products obtained by the present example and a comparative example.

Claims (1)

[Claims] 1. A bundled yarn in which a plurality of fibers are bundled with a water-soluble polymer resin, and the fibrillation degree at pH 12 is 50%.
A bundled yarn characterized by the above.