JP2004217486A - Cut fiber for concrete reinforcement - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a concrete reinforcement cut fiber which exhibits excellent dispersibility in concrete and an enhanced effect of the improvement of the concrete performance such as mechanical strength. <P>SOLUTION: Th cut fiber for concrete reinforcement is composed of a polyamide-based fiber on which a treating agent is stuck. The treating agent has 115 to 140 mN sticking tension of water to the fiber in a 25°C atmosphere and 75 to 100% detachment rate in water. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【００７２】
表１の結果から明らかなように、実施例１〜３で用いた処理剤は、２５℃における水の付着張力が１１５〜１４０ｍＮの値を示し、２５℃の水中脱落率も７５〜１００％の値を示しているため、これらの処理剤を付与したナイロン６繊維は延伸性が良好であり、ナイロン６カットファイバーのコンクリート中での分散性も良好であった。
【００７３】
一方、処理剤中のポリオキシエチレン硬化ヒマシ油エーテル量が少ない比較例１の処理剤は、２５℃における水の付着張力が１１５ｍＮ未満であり、２５℃の水中脱落率も７５％未満である。その処理剤を付与したナイロン６繊維は、延伸性良好であるが、ナイロン６カットファイバーのコンクリート中での分散性については十分ではなかった。
【００７４】
また、処理剤中のポリオキシエチレン硬化ヒマシ油エーテルの酸化エチレン付加モル数が少ない比較例２の処理剤は、２５℃における水の付着張力は１１５ｍＮ以上であるが、２５℃の水中脱落率が７５％未満であるためナイロン６繊維は延伸性良好であるが、ナイロン６カットファイバーのコンクリート中での分散性については十分ではなかった。
【００７５】
処理剤中のポリオキシエチレン硬化ヒマシ油エーテル量が多い比較例３は、２５℃における水中脱落率は７５％以上であるが、２５℃における水の付着張力が１４０ｍＮを越えるためナイロン６カットファイバーのコンクリート中での分散性は良好であるものの、ナイロン６繊維は繊維−金属間の摩擦抵抗が高いため延伸性不良であった。
【００７６】
【発明の効果】
以上記述したように、本発明のコンクリート補強用カットファイバーは、製糸工程での糸揺れ、静電気、スカムなどのトラブルもなく良好な操業性で製糸されたポリアミド系合成繊維からなるものであり、コンクリート中での分散性に優れ、コンクリート強度などのコンクリート性能向上効果が効果的に改善されたものである。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a cut fiber for reinforcing concrete. More specifically, the present invention relates to a cut fiber for concrete reinforcement which has excellent dispersibility in concrete and has an improved effect of improving concrete performance such as concrete strength.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in order to reinforce concrete and prevent cracks and the like, a reinforcing fiber is mixed with concrete. Glass fiber, carbon fiber, synthetic polymer fiber, or the like is used as the reinforcing fiber, and the form is often used as a cut fiber.
[0003]
In order to sufficiently exert the reinforcing effect of the cut fiber, it is important to sufficiently disperse the cut fiber in the concrete. This dispersibility is not only the characteristic of the cut fiber itself, but also the treatment agent attached to the cut fiber. Also depends on.
[0004]
Various cut fibers have been proposed as concrete reinforcing fibers, and various treatment agents to be attached to them have been proposed.
[0005]
For example, as a treating agent to be attached to carbon fibers, a silane coupling agent and a polyethylene oxide compound (for example, see Patent Document 1), an aminosilane coupling agent (for example, see Patent Document 2), a polyester copolymer (for example, Patent Reference 3), silicon rubber fine particles (for example, see Patent Literature 4), humic acids (for example, see Patent Literature 5), polyethylene glycol (for example, see Patent Literature 6), and polypropylene fibers. As a treating agent to be adhered to, for example, an alkyl phosphate salt (for example, see Patent Document 7) has been proposed.
[0006]
Further, for polyvinyl alcohol-based fibers, since the fibers themselves have a strong hydrophilicity, no treatment agent considering dispersibility in concrete is used (for example, see Patent Documents 8, 9, and 10). .
[0007]
On the other hand, as for the polyamide-based fiber, since the hydrophilicity of the fiber itself is not so bad, a treating agent in consideration of dispersibility in concrete has not been used (for example, see Patent Document 11).
[0008]
In general, a polyamide synthetic fiber treating agent is applied to a polyamide synthetic fiber in the spinning process in order to smoothly perform each of the steps of spinning and high-order processing and obtaining a high-quality final product. The fiber treating agent used in this case has lubricating, bunching, and antistatic properties so that each step of yarn production and higher-order processing can be smoothly performed and a high-quality final product can be obtained. It is required to have a function of imparting properties such as properties. In particular, when used as a cut fiber for concrete reinforcement, in addition to the above properties, excellent dispersibility is required so that the cut fiber is uniformly dispersed in the concrete. No consideration has been given to a treating agent for polyamide-based synthetic fibers in consideration of the above.
[0009]
In addition, the treatment agent for improving the dispersibility in concrete is different depending on the fiber type of the cut fiber, and even if the above treatment agents are directly applied to the polyamide cut fiber, a good dispersibility improvement effect can be obtained. Not always.
[0010]
[Patent Document 1]
JP-A-3-150241
[Patent Document 2]
JP-A-3-150242
[Patent Document 3]
Japanese Patent Application Laid-Open No. 5-2955663
[Patent Document 4]
JP-A-7-26421
[Patent Document 5]
JP-A-11-60309
[Patent Document 6]
JP-A-11-116295
[Patent Document 7]
JP-A-6-248506
[Patent Document 8]
JP-A-3-82815
[Patent Document 9]
JP-A-4-126835
[Patent Document 10]
Japanese Patent Application Laid-Open No. 4-163331
[Patent Document 11]
JP 2002-137942 A
[Problems to be solved by the invention]
The present invention has been achieved as a result of studying solving the problems in the above-described conventional technology.
[0022]
Accordingly, an object of the present invention is to provide a cut fiber for concrete reinforcement which has excellent dispersibility in concrete and has an improved effect of improving concrete performance such as concrete strength.
[0023]
[Means for Solving the Problems]
The present inventors have intensively studied the interfacial physical properties of the fiber surface on the dispersibility of cut fibers in concrete in order to achieve the above object, and the higher the water adhesion tension on the fiber surface, the more the treating agent It has been found that the higher the falling-off rate in water, the better the dispersibility in concrete, and the present invention has been completed. That is, the concrete-reinforcing cut fiber of the present invention is a concrete-reinforcing cut fiber made of a polyamide-based fiber to which a treating agent has been attached, and has an adhesion tension of water of 115 to 140 mN with respect to the fiber in a 25 ° C atmosphere of the treating agent. And an underwater shedding rate of 75 to 100%.
[0024]
In addition, in the cut fiber for reinforcing concrete according to the present invention, the polyamide fiber has a single fiber fineness of 5 to 30 dtex, and the treating agent is a poly (propylene oxide) obtained by adding 20 to 30 mol of ethylene oxide to 1 mol of hardened castor oil. Both the fact that the oxyethylene hydrogenated castor oil ether is contained in an amount of 15 to 40% by weight as a pure component and that the treatment agent is attached in an amount of 0.8 to 1.6% by weight based on the weight of the fiber. These conditions are preferable, and by applying these conditions, a more excellent effect can be expected.
[0025]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the cut fiber for concrete reinforcement of the present invention will be described in detail.
[0026]
The fiber material used for the cut fiber of the present invention is polyamide. Known polyamides are used as the fiber material, and are not particularly limited. Examples include polyhexamethylene adipamide (nylon 66), polycapramide (nylon 6), polytetramethylene adipamide (nylon 46), and copolymers and blends of these polymers. Although a corresponding effect can be obtained, a cut fiber excellent in performance such as excellent dispersibility of fiber in concrete and strength can be obtained particularly when polycapramide (nylon 6) fiber is used.
[0027]
The fiber for cut fiber in the present invention is made of the above polyamide, and is desirably a fiber made of a high molecular weight polyamide polymer having a sulfuric acid relative viscosity of 3.0 or more, preferably 3.2 or more. Here, if the sulfuric acid relative viscosity of the polyamide is less than 3.0, it may be difficult to obtain the strength intended by the present invention.
[0028]
Further, the fiber for cut fiber in the present invention is preferably a polyamide fiber comprising a multifilament having a single yarn fineness of less than 30 dtex, particularly 5 to 30 dtex, and having 30 or more single yarns. Furthermore, it is more preferable that the single yarn fineness is less than 10 dtex and the number of single yarns is 100 or more.
[0029]
In the present invention, a treatment agent is attached to the cut fiber as described above. The treating agent is generally applied to the fiber yarn in the spinning step of the polyamide fiber, but may be applied in a post-processing step. The treating agent used for the cut fiber for concrete reinforcement of the present invention may be diluted with a solvent such as a water emulsion or a low-viscosity mineral oil or in the state of the treating agent itself, such as roller oiling or guide oiling. It is applied to the fiber yarn by a known method.
[0030]
The treatment agent used for the cut fiber for concrete reinforcement of the present invention, when adhered to the fiber, has a water adhesion tension of 115 to 140 mN on the fiber surface in a 25 ° C atmosphere measured by the method described later, and is described later. It is an essential condition that the falling-off rate in water at 25 ° C. measured by the method is 75 to 100%.
[0031]
If the adhesion tension of water in the atmosphere of the treatment agent at 25 ° C. is less than 115 mN, the dispersibility of the cut fiber in the concrete becomes poor, and if it exceeds 140 mN, the anchor effect for reinforcing the concrete is impaired. Therefore, the dispersibility of the fiber in the concrete and the concrete reinforcing performance of the present invention cannot be satisfied.
[0032]
On the other hand, if the rate of the treatment agent falling off from the fiber surface in water is less than 75%, the effect of improving the dispersibility of cut fibers in concrete, which is the object of the present invention, cannot be obtained.
[0033]
The treating agent used for the cut fiber for reinforcing concrete of the present invention preferably contains a lubricant. The lubricant used here, when used as a treating agent, imparts lubricity, bundling properties, antistatic properties, etc. to the polyamide fiber, smoothly progresses each process of yarn production and processing, and provides high quality textile products. And the properties that do not impair the dispersibility of the cut fibers in concrete, that is, the adhesion tension of water to the fiber surface at 25 ° C. does not fall outside the range of 115 to 140 mN, and the rate of falling off in water at 25 ° C. is 75 to 100 mN. %, It is possible to use a conventional lubricant that has been generally used as it is.
[0034]
Examples of such lubricants include mineral oils, animal and vegetable oils (eg, coconut oil, rapeseed oil, olive oil, etc.), silicone oils (eg, polydimethylsiloxane, methylphenylsiloxane, polyepoxysiloxane, amino-modified siloxane, etc.), and monovalent. Esters of alcohols with monocarboxylic acids (eg, methyl oleate, butyl stearate, isooctyl stearate, isooctyl oleate, lauryl oleate, isotridecyl stearate, hexadecyl stearate, isostearyl oleate, oleyl laurate, oleyl Oleates), esters of polyhydric alcohols and monovalent carboxylic acids (eg, diethylene glycoldiolate, hexamethylene glycoldiolate, neopentyl glycol dilaurate, trimethylolpropanate) Caprylate, glycerin triolate, pentaerythritol tetraolate, bisphenol A dilaurate, thiodipropanol dilaurate, etc., esters of polyhydric carboxylic acids and monohydric alcohols (eg dioleyl malate, diisotridecyl adipate, dioleyl adipate, Dioctyl sebacate, dioctyl azelate, dioctyl phthalate, trioctyl trimellitate, etc., an ester of an alcohol to which an alkylene oxide has been added and a carboxylic acid (for example, dovanol 23 having 2 moles of ethylene oxide added thereto (manufactured by Mitsubishi Chemical Corporation) Alcohol) and lauric acid, 2 moles of propylene oxide, isotridecyl alcohol and lauric acid, 2 moles of ethylene oxide A diester of dovanol 23 and adipic acid), an alkylene oxide copolymer and a derivative thereof (for example, a block or random copolymer of ethylene oxide and propylene oxide, and both or one of the terminals of the copolymer are alcohol or carboxylic acid). And a thiobisphenol derivative or a thioether of a long-chain hydrocarbon.
[0035]
The above lubricants can be used alone, but if necessary, two or more of them can be used in combination.
[0036]
The amount of the lubricant is not particularly limited, but is usually 20 to 95% by weight, more preferably 50 to 90% by weight, based on the total pure content in the treating agent.
[0037]
The treating agent used for the cut fiber for concrete reinforcement of the present invention is prepared by emulsifying the above-mentioned lubricant in water or blending a surfactant to assist the adhesion to the cut fiber. The use of a surfactant, in addition to its original function of imparting antistatic properties and bundling properties to the fiber yarn, is excellent in dispersibility in concrete, which is the object of the present invention, and improves the affinity with water. The effect is obtained.
[0038]
Examples of the surfactant used here include polyoxyethylene hydrogenated castor oil ether, nonionic surfactants (eg, polyoxyethylene lauryl ether, polyoxyethylene oleyl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene) Ethylene lauryl amino ether, polyethylene glycol monolaurate, polyethylene glycol dilaurate, polyethylene glycol monooleate, polyethylene glycol dioleate, glycerin monooleate, sorbitan monooleate, polyoxyethylene glycerin monolaurate, polyoxyethylene sorbitan triolate, polyoxy Ethylene castor oil ether, etc.), anionic surfactants (eg, dioctyl sulfosuccinate Na salt, lauryl sulfo) Sodium salt, sodium dodecylbenzenesulfonic acid salt, ethylene oxide-added lauryl sulfate K salt, etc.), and cationic surfactants (eg, oleyldimethylamine phosphate adduct, polyoxyethylene laurylamine lactate adduct, lauryltrimethylammonium bromide) , Stearyldimethylhydroxyethylammonium nitrate, etc.). Other examples include betaine-based activators, silicone-based activators, and fluorine-based activators.
[0039]
Out of these surfactants, when used as a treating agent, they have excellent hydrophilicity such that the adhesion tension of water to the fiber surface in a 25 ° C. atmosphere is 115 to 140 mN, and the falling-off rate in water is 75 to 100%. It is preferable to select and use a surfactant. For example, among the above-mentioned surfactants, polyoxyethylene hydrogenated castor oil ether is particularly excellent. When this surfactant is used, it is preferable that the processing agent contains 15 to 40% by weight of a pure component of a hydrogenated castor oil to which 20 to 30 mol of ethylene oxide is added. When the number of moles of ethylene oxide added to the polyoxyethylene-hardened castor oil ether is less than 20 mol, the adhesion tension of water to the fiber surface may be less than 115 mN, and when it exceeds 30 mol, it becomes a solid at room temperature and becomes It may cause trouble of scum generated in the processing step. When the content of the polyoxyethylene hydrogenated castor oil ether in the treating agent is less than 15%, the adhesion tension of water to the fiber may be less than 115 mN, and the content of the polyoxyethylene hydrogenated castor oil ether is 40%. %, The friction between the fiber and the metal increases, which may hinder the operability of the yarn making and processing steps.
[0040]
The above-mentioned surfactants can be used alone or, if necessary, in combination of two or more.
[0041]
The amount of the surfactant is not particularly limited, but is usually 0.5 to 80% by weight, more preferably 10 to 50% by weight as a pure content relative to the total pure content in the treating agent. is there.
[0042]
In the treating agent used in the present invention, in addition to the above-mentioned components, other components, for example, additives such as an antifoaming agent and a preservative can be added as long as the effects of the present invention are not impaired. . It is preferable to use an aqueous emulsion containing these lubricants, surfactants and, if necessary, other additives.
[0043]
In the present invention, the amount of the treatment agent attached to the cut fiber is 0.8 to 1.6% by weight, preferably 0.9 to 1.3% by weight, based on the weight of the fiber.
[0044]
If the amount of the treating agent is less than 0.8% by weight, the absolute amount of the treating agent that dissolves in water is small even if the falling-off rate in water is 75% or more, and good dispersibility may not be obtained. . If the amount of the treatment agent is more than 1.6% by weight, good dispersion can be obtained, but the scattering amount at the time of lubrication of the treatment agent in the yarn-making process and the viscosity of the fiber surface increase, so that the godet roll can be removed. Winding may occur, which may cause a decrease in operability.
[0045]
Next, a specific example of the method for producing the cut fiber for concrete reinforcement of the present invention will be described.
[0046]
First, a polyamide composition is prepared by adding a copper compound as an antioxidant and an alkali metal halide to a polyamide polymer having a sulfuric acid relative viscosity of 3.0 or more, if necessary.
[0047]
Next, the polyamide composition is dried so that the moisture content becomes 0.2% by weight or less, and then melted at a spinning temperature of 280 to 310 ° C using an extruder-type spinning machine.
[0048]
Subsequently, the molten polymer is filtered in a spin pack through a metal nonwoven fabric filter having pores of about 5 to 50 μm, and then spun through the mouth of the spinneret.
[0049]
A heating cylinder having a length of 10 to 100 cm, preferably 15 to 50 cm is installed directly below the base, and the atmosphere temperature in the heating cylinder is set to 250 ° C. or higher, preferably 280 to 310 ° C.
[0050]
The yarn gradually cooled by passing through the heating cylinder atmosphere is then blown with cold air to be rapidly cooled and solidified.
[0051]
Next, a treatment agent is applied to the yarn. As described above, the treating agent used here is preferably an aqueous emulsion treating agent comprising a lubricant, a surfactant, and if necessary, an additive. The lubricant has the effect of reducing the frictional resistance between the yarn and the metal in the spinning process, and the surfactant has the effect of performing an emulsifying action to make the lubricant a stable emulsion. Higher workability, for example, has the effect of improving the dispersibility of filament fibers in the concrete intended for the present invention. The additives include an antistatic agent, an extreme pressure agent, a heat resistant agent, and the like, and impart effects such as antistatic, extreme pressure, and heat resistance, respectively.
[0052]
In the method for producing the fiber for cut fiber of the present invention, in order to obtain the cut fiber having the desired properties, the lubricant and the surfactant component in the component of the aqueous emulsion treating agent imparted to the fiber play an important role. Fulfill. That is, a lubricant and a surfactant component, and a lubricant and a surfactant component thereof, so that the adhesion tension of water to the fiber surface in a 25 ° C. atmosphere is 115 to 140 mN and the rate of the treatment agent falling off in water in a 25 ° C. atmosphere is 75 to 100%. Must be appropriately selected. Specifically, 20 to 95% by weight of a lubricant such as a mineral oil and 0.5 to 80% by weight of a surfactant such as a polyoxyethylene hydrogenated castor oil ether are appropriately mixed, and if necessary, What is necessary is just to give the processing agent which added the additive so that it might be 0.8-1.6 weight% with respect to fiber weight.
[0053]
The polyamide yarn to which the aqueous emulsion oil agent has been applied is taken up by a take-up roll at a speed of 300 to 1000 m / min, preferably 450 to 800 m / min, and the taken-up yarn is continuously wound without being wound once. It is sent to a stretching step and is subjected to stretching.
[0054]
The total stretching ratio is 3.5 to 6.5 times, and the stretching temperature is such that the final stretching temperature is 210 ° C. or higher, preferably 215 to 250 ° C.
[0055]
In addition, a heat relaxation treatment is performed subsequent to the stretching, and this heat treatment is usually performed under the condition of 5 to 15% relaxation between the final stretching roll and the relaxing roll arranged thereafter.
[0056]
The nylon 6 fiber produced by spinning and drawing in this way is cut into a fiber length of 0.5 to 3.0 cm with a cutter or the like to obtain a nylon 6 cut fiber, thereby providing a cut fiber for concrete reinforcement according to the present invention. Is manufactured.
[0057]
The thus obtained cut fiber for reinforcing the concrete of the present invention may be mixed at any stage as a raw material when preparing concrete, but usually the main raw material is cement, sand, gravel and water. Mixing and kneading with the base concrete, and the kneaded cut fiber-containing concrete may be applied to a predetermined position using a concrete pump or the like. The amount of the base concrete cement, sand, gravel and water is 100 to 200 parts by weight of sand, 200 to 400 parts by weight of gravel, and 30 to 100 parts by weight of water based on 100 parts by weight of commonly used cement. . The cut fiber is added in an amount of 0.5 to 3 parts by weight based on 100 parts by weight of the base concrete.
[0058]
In addition, the cut fiber for concrete reinforcement of the present invention can be suitably used not only for the above-described concrete but also for mortar and cement mortar.
[0059]
【Example】
Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited to these Examples. In Examples, the amounts of each component are expressed in weight% unless otherwise specified.
[0060]
Various properties in the above and the following examples were measured by the methods described below.
[Water adhesion tension]
Using a sample prepared under the following conditions, a dynamic wettability tester “WET-6000” manufactured by Resca Co., Ltd. was used under the following conditions (unit: mN: millinewton).
[0061]
(Method of preparing sample for measurement)
The nylon 6 fiber described in the example was used as a taffeta, cut into a size of 30 cm in length and 20 cm in width, and subjected to target treatment using a mangle (using VARIOUS TEXTILE FINISHING MACHINES model VPM-1 manufactured by TSUJII DYEING MACHINE MFG.CO. LTD). After dip nip so that the amount of the applied agent becomes 1.0%, a drying treatment at 105 ° C. × 2 minutes is performed using a pin tenter type baking tester (model DK-5E) manufactured by Daiei Kagaku Seiki Seisaku-sho, Ltd. went. The obtained sample was cut into a strip having a size of 2.5 cm in length and 1.5 cm in width, and was used as a sample for measuring the adhesion tension. The dip solution used for the dip nip was prepared by diluting a treatment agent with water.
[0062]
(Setting conditions during measurement)
Immersion depth of sample: 1mm
Immersion speed of sample: 0.5 mm / sec Measurement time: 20 seconds The water used for the main measurement has a surface tension of 65 mN / measured by KYOWA CBVP SURFACE TENTION METER (25 ° C., platinum plate) manufactured by Kyowa Chemical Industry Co., Ltd. cm of distilled water.
[Slipping rate of treatment agent in water]
First, the treatment agent adhesion amount of the cut fiber is measured by the method described in JIS-L-1017. Next, 1000 ml of distilled water is put into a 1000 ml beaker, and the water temperature is adjusted to 25 ° C. While stirring the water with a magnetic stirrer having a length of 4 cm at a rotation speed of 250 rpm, 3.0 g of the cut fiber is introduced.
[0063]
After stirring for 2 minutes, the fiber was taken out, the remaining amount of the treating agent was measured by the method described in JIS-L-1017, and the falling-off rate of the treating agent in water was determined by the following equation.
[0064]
Treatment agent drop-off rate = (treatment agent adhesion amount−treatment agent residual amount) / treatment agent adhesion amount × 100
[Dispersibility in concrete]
4.5 kg of ordinary Portland cement (manufactured by Taiheiyo Cement), 4.5 kg of sand (size 6 silica sand), 2.5 kg of water, 90 g of 1.5 cm long cut fiber are put into a concrete mixer, mixed for 5 minutes, and dispersed. The properties were visually observed and determined as follows. The cut fiber mass described below refers to a bean-sized mass formed by intertwining multifilaments.
[0065]
：: Almost no lump of cut fiber.
[0066]
Δ: A small amount of cut fiber mass is present.
[0067]
×: Many cut fiber lumps are present.
[Examples 1 to 3, Comparative Examples 1 to 3]
To a nylon 6 fiber yarn obtained by melt-spinning a nylon 6 resin having a sulfuric acid relative viscosity of 3.7 by a usual method, a treating agent having the composition shown in Table 1 was applied by 1.0% by weight using a roller oiling method. The fiber yarn was subjected to multi-stage hot drawing (final hot roller temperature: 200 ° C.) at a draw ratio of 4.5 times without winding once to obtain 1400 dtex / 210fil (decitex / filament) nylon 6 fiber. The obtained nylon 6 fiber was cut into a fiber length of 1.5 cm with a cutter to obtain a nylon 6 cut fiber.
[0068]
Table 1 also shows the results of evaluating the adhesion tension of water, the falling-off rate, and the dispersibility in concrete of the treatment agent in the cut fiber thus obtained.
[0069]
Table 1 also shows the results obtained by converting the number of yarn breaks in the yarn making process per ton of yarn as drawability.
[0070]
In both the examples and the comparative examples, the yarn could be smoothly produced without troubles such as yarn sway, static electricity and scum in the yarn production process.
[0071]
[Table 1]

[0072]
As is clear from the results in Table 1, the treatment agents used in Examples 1 to 3 exhibited a water adhesion tension at 25 ° C of 115 to 140 mN, and a 25% drop-off rate of water at 75 ° C of 75 to 100%. Since these values are shown, the nylon 6 fibers to which these treatment agents were applied had good stretchability, and the dispersibility of the nylon 6 cut fibers in concrete was also good.
[0073]
On the other hand, the treating agent of Comparative Example 1 having a small amount of polyoxyethylene hydrogenated castor oil ether in the treating agent has an adhesion tension of water at 25 ° C. of less than 115 mN, and a falling-off rate at 25 ° C. in water of less than 75%. The nylon 6 fiber to which the treating agent was applied had good stretchability, but the dispersibility of the nylon 6 cut fiber in concrete was not sufficient.
[0074]
The treating agent of Comparative Example 2 in which the number of moles of ethylene oxide added to the polyoxyethylene-hardened castor oil ether in the treating agent was small had an adhesion tension of water of 115 mN or more at 25 ° C., but had a falling rate in water at 25 ° C. Since it is less than 75%, the stretchability of the nylon 6 fiber is good, but the dispersibility of the nylon 6 cut fiber in concrete is not sufficient.
[0075]
In Comparative Example 3 in which the amount of polyoxyethylene-hardened castor oil ether in the treating agent was large, the falling-off rate in water at 25 ° C was 75% or more, but the adhesion tension of water at 25 ° C exceeded 140 mN. Although dispersibility in concrete was good, nylon 6 fiber had poor stretchability due to high frictional resistance between fiber and metal.
[0076]
【The invention's effect】
As described above, the cut fiber for concrete reinforcement of the present invention is made of a polyamide-based synthetic fiber that has been produced with good operability without troubles such as yarn sway, static electricity, and scum in the yarn production process. It has excellent dispersibility in the inside, and the effect of improving concrete performance such as concrete strength is effectively improved.

Claims (4)

A concrete reinforcing cut fiber made of a polyamide-based fiber to which a treating agent is attached, wherein the adhesion tension of water on the fiber surface in a 25 ° C atmosphere is 115 to 140 mN, and the rate of dropping of the treating agent in water at a 25 ° C atmosphere is reduced. A cut fiber for concrete reinforcement characterized by being 75-100%. The cut fiber for concrete reinforcement according to claim 1, wherein the single fiber fineness of the polyamide fiber is 5 to 30 dtex. The said treating agent contains 15-40 weight% as a pure component polyoxyethylene hardened castor oil ether which added 20-30 moles of ethylene oxides to 1 mole of hardened castor oil. 2. The cut fiber for reinforcing concrete described in 2. The cut fiber for reinforcing concrete according to any one of claims 1 to 3, wherein the treatment agent is attached in an amount of 0.8 to 1.6% by weight based on the fiber weight.