JP2018111632A - Fiber material for cement reinforcement - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fiber material for cement reinforcement which has high convergence properties and excellent reinforcement effect, and to particularly provide a fiber material for cement reinforcement which is excellent in a reinforcement effect relative to concrete or mortar having high viscosity.SOLUTION: A fiber material for cement reinforcement is a fiber bundle formed of an aromatic polyamide fiber, where the aromatic polyamide fiber is an epoxy pretreatment yarn, the fiber bundle is obtained by twisting, and the surface of the fiber bundle is covered with a resin containing an isocyanate compound as a main component. Preferably, the resin is a resin containing polyol or epoxy compound as a component, in addition to the isocyanate compound. A method for producing a fiber material for cement reinforcement includes twisting an aromatic polyamide fiber treated with an epoxy compound, and then subjecting the aromatic polyamide fiber to coating treatment with a resin containing an isocyanate compound as a main component. Concrete or mortar molded body contains the above material.SELECTED DRAWING: None

Description

  The present invention relates to a fiber material suitable for cement reinforcement, and more particularly to a fiber material for cement reinforcement optimal for the production of concrete, mortar and the like.

  Concrete or mortar moldings are used in large quantities in the construction and civil engineering fields because they are inexpensive in addition to excellent properties such as compressive strength, durability, and incombustibility. However, these molded products are brittle substances, and have the disadvantages that they are easily cracked or broken when stress such as tension, bending, or bending is applied.

  In order to compensate for this drawback, reinforcement using an organic polymer such as aramid fiber is effective. By reinforcing with these fibers, it becomes possible to improve the mechanical properties such as bending strength and bending toughness of cement molded bodies such as cement paste, mortar, or concrete. It is important that each fiber is uniformly dispersed in the concrete molding and is firmly bonded to the surrounding concrete.

However, even when these reinforcing fibers are used, there are problems such as dispersibility of the fibers in the concrete and generation of fiber lumps due to entanglement of the fibers during stirring.
For example, in Patent Document 1, as a method of using a bundle of fibers made of a large number of thin filaments (multifilaments) and using the cut fiber bundle as a reinforcing material, non-volatile oil is attached to the fibers bundled with the resin. Thus, a technique for improving the fiber bundle is disclosed. However, since the oil adheres to the fiber surface, the binding property is excellent, but the adhesion force between the cement mortar or concrete and the fiber is conversely reduced.

JP 2007-131464 A

  An object of the present invention is to provide a fiber material for cement reinforcement having a high convergence property and an excellent reinforcing effect, and particularly to provide a fiber material for cement reinforcing having an excellent reinforcing effect for highly viscous concrete or mortar. is there.

The fiber material for cement reinforcement of the present invention is a fiber bundle made of aromatic polyamide fiber, the aromatic polyamide fiber is an epoxy pretreated yarn, the fiber bundle is twisted, and the surface thereof is mainly composed of an isocyanate compound. It is covered with a resin as a component.
Furthermore, the resin is preferably a resin containing a polyol or an epoxy compound as a constituent component in addition to the isocyanate compound.
Another method for producing a fiber material for cement reinforcement according to the present invention is characterized in that an aromatic polyamide fiber previously treated with an epoxy compound is twisted and then coated with a resin mainly composed of an isocyanate compound. And
Moreover, this invention includes the concrete or mortar molded object containing the fiber material for cement reinforcement of said invention.

  ADVANTAGE OF THE INVENTION According to this invention, the fiber material for cement reinforcement which is excellent in the concentrating property with respect to the concrete material or mortar with high convergence property, especially the cement reinforcement or mortar with high viscosity is provided.

Hereinafter, the present invention will be described in detail.
The fiber material for cement reinforcement of the present invention is a fiber bundle made of aromatic polyamide fiber, the aromatic polyamide fiber is an epoxy pretreated yarn, the fiber bundle is twisted, and the surface thereof is mainly composed of an isocyanate compound. It is a fiber material coated with a resin as a component.

The aromatic polyamide fiber used for the reinforcing fiber material of the present invention is a fiber generally called an aramid fiber, and examples thereof include a para-aramid fiber and a meta-aramid fiber. Of these, fibers made of para-aramid such as polyparaphenylene terephthalamide and copolyparaphenylene 3,4'oxydiphenylene terephthalamide are preferable because they have a greater reinforcing effect than other fibers, particularly copolyparaphenylene-3. , 4 'oxydiphenylene terephthalamide fiber is less deteriorated in mechanical properties even if it is kept in a strong alkaline atmosphere under high temperature and high pressure for a long time. Steam curing under high temperature and high pressure, for example, 180 ° C, pressure of about It is preferable because it has a high strength retention even under conditions of saturated steam of 10 kg / cm ² .

  The single yarn fineness of the fiber is desirably 0.5 to 100 dtex. If the fineness of the single yarn is less than 0.5 dtex, it becomes difficult to align the single yarn, and if the alignment is insufficient, the mechanical performance of the fiber cannot be fully utilized. In addition, adhesion spots of the resin serving as a sizing agent tend to occur between single yarns, and a predetermined sizing property may not be obtained. In particular, this tendency becomes remarkable when the number of single yarns is increased. On the other hand, when the fineness of the single yarn exceeds 100 dtex, the bonding area between the single yarns decreases, and it becomes difficult to maintain the bundling by the bundling agent, and the object of the present invention is not achieved. More preferably, the single yarn fineness of the bundled fibers is preferably 0.6 to 80 dtex, more preferably 0.7 to 60 dtex.

  The fiber material used in the present invention is composed of a fiber bundle in which single yarns as described above are assembled, and further, the fiber bundle is twisted. The number of single yarns constituting the fiber bundle is preferably 50 to 5000 single fibers. Furthermore, it is preferable that the fiber bundle is composed of 100 to 2500 single fibers. Furthermore, it is preferable that a plurality of fiber bundles are combined with each other, and further, twisted after the combination.

  In addition, the aromatic polyamide fiber used in the present invention needs to be an epoxy pretreated yarn. This epoxy pretreated yarn is a fiber having an epoxy compound applied to the fiber surface by impregnating and drying the treatment liquid containing the epoxy compound at the spinning stage before twisting.

  The epoxy compound preferably used in the epoxy pretreated yarn of the present invention is preferably a compound having at least two epoxy groups in one molecule. More specifically, reaction products of polyhydric alcohols such as ethylene glycol, glycerol, sorbitol, pentaerythritol, polyethylene glycol and halogen-containing epoxides such as epichlorohydrin, resorcin, bis (4-hydroxyphenyl) dimethylmethane, Reaction products of polyhydric phenols such as phenol / formaldehyde resins and resorcin / formaldehyde resins with the halogen-containing epoxides, polyepoxide compounds obtained by oxidizing unsaturated compounds with peracetic acid or hydrogen peroxide, that is, 3,4-epoxycyclohexylene epoxide, 3,4-epoxycyclohexylmethyl, 3,4-epoxycyclohexenecarboxylate, bis (3,4-epoxy-6-methyl-cyclohexylmethyl) azi Mention may be made of the over door or the like. Among these, a reaction product of a polyhydric alcohol and epichlorohydrin, that is, a polyglycidyl ether compound of a polyhydric alcohol such as glycerol can be preferably exemplified because it can exhibit excellent performance.

  Such polyepoxide compounds are usually used as an aqueous solution or an emulsion. In order to obtain an emulsified liquid or solution, for example, a polyepoxide compound as it is or dissolved in a small amount of a solvent as necessary is used as a known emulsifier such as sodium alkylbenzene sulfonate, dioctyl sulfosuccinate sodium. It can be emulsified or dissolved using a salt, nonylphenol ethylene oxide adduct or the like.

  The pretreated yarn used in the present invention is obtained by treating fibers with a treatment liquid having the above composition, but the solid concentration of the treatment liquid is preferably 1 to 30% by weight. And it is preferable that the adhesion amount to the fiber of a processing agent is the range of 0.1-10 weight%.

  In addition, the fiber material for cement reinforcement of the present invention is a fiber material in which the fiber material is twisted on a fiber bundle composed of the epoxy pretreated yarn, and the twist coefficient thereof is in the range of 0 to 3. It is preferably twisted. Furthermore, the twist coefficient is preferably in the range of 0-2. When the twisting coefficient is too large, a force perpendicular to the fiber axis direction due to the single yarns is more applied when pulled, and the strength tends to be lowered for fibers that are weak against bending. Moreover, the uniform impregnation property of resin used as a sizing agent is impaired, the elongation increases due to twisting and shrinkage, and the reinforcing property of cement mortar or concrete tends to be impaired. By being twisted within the range of the appropriate twisting factor, integration as a reinforcing material is enhanced when it is bundled with a resin, and even when kneaded in cement mortar or concrete, the bundling is maintained, and the fluidity of the material The workability can be ensured.

  Here, the twisting coefficient in the present invention is indicated by the product of the number of twists per unit length and the square root of the fiber fineness, and the following formula described in ASTM D885; twisting coefficient = {twisting number ( Times / m) × √fiber fineness (tex)} / 1055.

  Moreover, it is preferable that the diameter of the fiber material for cement reinforcement of the present invention comprising a fiber bundle in which a plurality of single yarns are gathered is in the range of 0.05 to 5.0 mm. Moreover, it is preferable that it is a short fiber, and it is preferable that the length is the range of 1-50 mm. In particular, such a range is preferable from the viewpoint of reinforcing effects due to fiber mixing, that is, cracking suppression, and imparting high bending strength and high bending toughness. If the diameter of the bundled fiber reinforcement material is too small or the fiber length is too long, the fiber material is likely to be subjected to shearing force when kneaded in cement mortar or concrete, and the resin bundling cannot be maintained. , Unbundling tends to break up into single fibers and tend to impair the fluidity of the material. On the other hand, if the fiber length of the focused fiber is too short, the contact area between the fiber and cement mortar or concrete is small, or if the diameter is too large, the total contact surface area between the fiber and cement mortar or concrete per unit volume is small. Therefore, there is a tendency that a sufficient reinforcing effect cannot be obtained. As a more preferable shape, the diameter of the bundled fiber reinforcing material is preferably 0.1 to 3 mm. The fiber length is preferably 5 to 40 mm.

Moreover, it is preferable that the fiber used for this invention is high intensity | strength, More specifically, it is preferable that the tensile strength of a fiber is 7 cN / dtex or more. Furthermore, it is preferable that it is the range of 10-40 cN / dtex. Here, when the tensile strength of the fiber is too low, when a load is applied to the cement mortar or concrete, the bending strength of the molded product is small, or the fiber tends to break and cannot absorb the impact sufficiently. .
In the cement reinforcing fiber material of the present invention, the surface of the fiber bundle made of the twisted epoxy pretreated yarn is coated with a resin mainly composed of an isocyanate compound.

  Examples of the resin mainly composed of an isocyanate compound that covers the fiber material include an isocyanate resin, a polyurethane resin, and a crosslinked product of isocyanate and epoxy. Furthermore, the resin is preferably a resin containing a polyol or an epoxy compound as a constituent component in addition to the isocyanate compound.

  The blocked isocyanate compound preferably used here is an addition compound of a polyisocyanate compound and a blocking agent, and it is preferable that the block component is liberated by heating to produce an active polyisocyanate compound. Examples of the polyisocyanate compound include polyisocyanates such as tolylene diisocyanate, metaphenylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, polymethylene polyphenyl isocyanate, triphenylmethane triisocyanate, and polyol adduct polyisocyanate containing a terminal isocyanate group. Can be mentioned. As a blocking agent for the blocked isocyanate compound, for example, dimethylpyrazole or the like is preferably used.

More specific isocyanate compounds may be selected from aromatic diphenylmethane diisocyanate, toluene diisocyanate, aliphatic hexamethylene diisocyanate, and the like. It is preferable to use an aliphatic isocyanate having excellent permeability into the fiber bundle. Furthermore, an agent composed of a blocked isocyanate and an epoxy compound is preferable. Moreover, it is preferable to process by an isocyanate process with an epoxy compound, especially the process liquid containing a block isocyanate compound.
Moreover, although resin, such as said isocyanate compound, contributes to fiber bundling, you may further coat | cover with the other resin in order to improve the adhesion performance with concrete or cement mortar on the surface.

  It is preferable that the adhesion amount of such resin is 3 to 15% by weight based on the total fiber weight. When the amount of adhesion is too small, the convergence is broken and the single fibers are scattered to tend to impair the fluidity of the material. This is because the fiber bundling by the bundling agent cannot be maintained when a shearing force is applied to the fiber during kneading with concrete or mortar. On the other hand, when there is too much adhesion amount, there exists a tendency for the intensity | strength of a fiber not to fully be utilized. When the adhesion amount is increased too much, the focusing property itself is not improved so much. Moreover, it is because the tensile strength of the bundling fiber per weight will fall by the increase in the apparent fineness of a fiber bundling body when the adhesion amount of resin increases.

  In addition to the resin as described above, the cement reinforcing fiber material of the present invention preferably further includes a resin having an epoxy resin as a constituent component on the surface of the fiber. Furthermore, from the viewpoint of cohesive strength and interfacial adhesive strength, acrylic-modified epoxy resin and bisphenol A type epoxy resin are preferable, and high performance is exhibited. In particular, a resin made of an acrylic-modified bisphenol A type epoxy resin is preferable. The adhesion amount of the epoxy resin is desirably 0.1 to 10% by weight based on the total fiber weight.

  Such a fiber material for cement reinforcement of the present invention can be obtained by the following production method. That is, it is a method in which an aromatic polyamide fiber previously treated with an epoxy compound is twisted and then coated with a resin containing an isocyanate compound as a main component.

  Here, as the aromatic polyamide fiber previously treated with the epoxy compound, the pretreated aromatic polyamide fiber described above can be used. As a method of attaching a resin mainly composed of an isocyanate compound used as a sizing agent in the present invention, such a fiber material is continuously fed from a bobbin or a beam creel, and the sizing agent is used. Examples thereof include a method of impregnating in a soot filled, a method of attaching by a roller touch method, and a method of spraying and attaching the sizing agent by a spray method. In particular, in order to uniformly adhere to the fiber, a method of impregnation in a cocoon containing a resin is preferable, and it is easy to adjust the amount of adhesion with a squeeze roll. In order to further impregnate and infiltrate the fiber bundle with the resin as the sizing agent, it is also preferable that the sizing agent is dispersed or dissolved in an aqueous system or an organic solvent and diluted. Moreover, it is preferable to use a water-based agent from the viewpoint of safety and work environment load. In order to ensure the penetration into the fiber bundle, it is preferable to use a relatively low molecular weight compound with improved water solubility.

  It is preferable that after the resin as a sizing agent is applied in this manner, a heat treatment is subsequently performed, and the dispersion medium of the sizing agent is dried and sometimes crosslinked by a heat treatment. The treatment apparatus is not particularly limited, and a contact type hot roller or the like can be used. Furthermore, when a non-contact type hot air drying furnace is used, the sizing agent can be operated without being attached to the apparatus or contaminated. Cheap.

  After the agent is attached, the fiber is dried by heat treatment, and it is preferably heat treated at 70 to 180 ° C. for 0.5 to 3.0 minutes for drying. Moreover, it is preferable that a crosslinking agent is included in a process liquid, and it is preferable to heat-process at 180 to 250 degreeC for bridge | crosslinking. If the drying temperature is too low or the drying time is too short, the drying is insufficient and the crosslinking process is performed at a higher temperature with water remaining inside the fiber. Is not preferable because it deteriorates. When the drying temperature is higher than 180 ° C., rapid evaporation of water and crosslinking occur simultaneously in the drying stage, which is not preferable because the film forming property deteriorates.

  Particularly, it is particularly preferable to use an aqueous dispersion of a blocked isocyanate having an aliphatic hexamethylene diisocyanate (HDI) structure excellent in penetrating into the fiber bundle and an epoxy compound having a highly water-soluble sorbitol polyglycidyl ether structure. preferable. More specifically, dimethylpyrazole block hexamethylene diisocyanate or caprolactam block diphenylmethane diisocyanate is preferably used as the blocked isocyanate, and a sorbitol polyglycidyl ether epoxy compound is used in combination as the epoxy compound.

  The amount of the resin adhering to the fiber bundle is preferably 5 to 15 wt% with respect to the fiber weight. The resin component used as the sizing agent is preferably a resin having high toughness that easily penetrates into the fiber bundle and easily bonds the single yarn to the single yarn in the fiber bundle. As a resin that satisfies these conditions, an isocyanate resin, a polyurethane resin, and a crosslinked product of isocyanate and epoxy are conceivable. The method of focusing with an isocyanate resin is not particularly limited, but a method in which fibers are immersed in a solution in which an isocyanate compound is dissolved in an organic solvent such as toluene and then obtained by self-crosslinking of the isocyanate compound by heat treatment, or an aqueous block Examples include a method obtained by immersing a fiber in an aqueous dispersion of deisocyanate and then obtaining it by self-crosslinking of an isocyanate compound from which a blocking agent has been dissociated by heat treatment. The reason why the blocked isocyanate is used in the case of an aqueous system is to suppress the deactivation of the functional group due to the reaction between water and isocyanate when the water is volatilized. The isocyanate compound may be selected from aromatic diphenylmethane diisocyanate, toluene diisocyanate, aliphatic hexamethylene diisocyanate, and the like. It is preferable to use an aliphatic isocyanate having excellent permeability into the fiber bundle. Moreover, although said isocyanate compound contributes to the bundling of a fiber, you may further coat | cover with the other resin in order to improve the adhesion performance with concrete or cement mortar on the surface.

  Further, the mixing rate of the fibers constituting the reinforcing fiber material of the present invention into cement mortar or concrete can be selected according to the purpose, but is usually used in the range of 0.01 to 10.0% by volume. It is preferable.

  The reinforcing fiber material of the present invention is particularly effective for cement which is a binder for concrete and mortar, and is preferably used for concrete reinforcement and mortar reinforcement. The cement as the binder for concrete or mortar is selected in consideration of on-site construction conditions and the like, but the fiber material for cement reinforcement of the present invention can be combined with various cements. More specifically, for example, various portland cements such as normal, early strength, ultra-early strength, low heat, and moderate heat, and various mixed cements such as blast furnace cement in which fly ash and blast furnace slag are mixed with these various portland cements. Fast-hardening cement or the like can be used alone or in admixture of two or more.

The cement reinforcing fiber material of the present invention is preferably used as a concrete or mortar material together with the cement (binding material) as described above, and becomes a concrete or mortar molded body containing the cement reinforcing fiber material.
At this time, together with the reinforcing fiber material of the present invention, the reinforced furnace cement includes blast furnace slag powder, fly ash, silica fume, limestone powder, quartz powder, dihydrate gypsum, hemihydrate gypsum, anhydrous gypsum, and quicklime-based expansion. It is preferable to add known admixtures (binding materials) such as wood and calcium sulfoaluminate-based expansion materials. The blending ratio is not particularly limited, and various designs can be performed.

In particular, the fiber material for cement reinforcement of the present invention has high fiber convergence even in a process such as cement kneading, and breakage occurs even in kneading that produces a high shearing force such as concrete or mortar with a low water / binder ratio. It was difficult to occur and did not hinder the fluidity and workability of the material. Further, the concrete or mortar molded product reinforced with the fiber material for cement reinforcement of the present invention does not cause abrupt fiber breakage even when the applied stress increases, and therefore greatly improves the bending fracture energy of the molded product. there were.
The use of the concrete or mortar molded body containing the cement reinforcing fiber material of the present invention is not particularly limited, and can be widely applied to general civil engineering and architectural uses.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. Various evaluations in the examples were measured as follows.

(1) Fiber length and fineness Measured according to JIS-L-1015.
(2) Fiber tensile strength It measured based on ASTM D885.
(3) Fiber bundle diameter and fiber bundle length of bundled fiber bundles After treating with resin, the treated fiber bundle (treated yarn) cut with the digital caliper (manufactured by A & D Co., Ltd.) The fiber bundle length was measured.

(4) Convergence after Cement Kneading In the following Examples and Comparative Examples, after kneading the cement, the unwinding of the reinforcing material in the cement mortar or concrete was visually confirmed and evaluated as follows. In particular, it was defined as untwisting that twisting is easy at the center of a short fiber, but bulging occurs from the end to the center of the short fiber by untwisting at the center.
○: 2 or less of the fiber bundles that were unwound in 10 pieces.
(Triangle | delta): The fiber bundle which thawed out of 10 is 3 or more and 8 or less.
X: Of 10 fibers, 9 or more fiber bundles were dissolved.

(5) Fluidity of raw cement In the following examples and comparative examples, a slump cone (height 15 cm, lower surface inner diameter 10 cm, upper surface inner diameter) on a horizontally disposed 50 cm square aluminum plate following the kneading step (4) above. The raw cement was poured into a 5 cm conical column with a hollow inside, and the slump cone was slowly pulled up vertically. At this time, raw cement spreads circularly on the aluminum plate. The diameter of the expanded circle at this time, or when the circle is distorted, an arithmetic average of the shortest diameter and the longest diameter was measured as a flow value. This flow value reflects the fluidity of raw cement.

(6) Compressive strength and bending fracture energy of mortar moldings Using the cement obtained in the following examples and comparative examples, a raw cement was placed in a mold having a width of 40 mm, a height of 40 mm, and a length of 160 mm, A specimen was produced by curing at 20 ° C. and 90% RH until the material age was 28 days. The above specimen was subjected to three-point bending measurement according to “JIS-R-5201”. More specifically, using a tensile compression tester for 10 tons (manufactured by TOYO BALDWIN, UNIVERSAL TESTING INSTRUMENT MODEL UTM 10t), the center of the fulcrum distance of 10 cm is compressed at a speed of 2 mm / min. The secondary yield point stress when the specimen was destroyed was calculated.

[Example 1]
A 6 mass% N-methylpyrrolidone (NMP) solution of copolyparaphenylene, 3,4'-oxydiphenylene, terephthalamide (fully aromatic polyamide having a copolymerization molar ratio of 1: 1) is prepared as a spinning solution. did. The spinning solution is discharged from the spinneret, spun into a coagulation bath filled with a 50 ° C. aqueous solution having an NMP concentration of 30% by mass through an air gap to obtain a coagulated yarn, and then washed in a water bath. And drying. Finally, after stretching 11 times at a temperature of 520 ° C., Neocor SW-30 (Dioctylsulfosuccinate) as a surfactant was added to 17.5 g of Denacol EX-313 (glycerol polyglycidyl ether, manufactured by Nagase ChemteX Corporation). Sodium salt, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 14.5 g, piperazine 4 g, water content 65% A copolyparaphenylene-3,4′-oxydiphenylene terephthalamide fiber having an epoxy compound treated on the surface of the single yarn was obtained. The physical properties of the obtained pretreated aramid fiber were 1670 dtex, 1000 filaments, tensile strength 24.5 cN / dtex, elongation at break 4.5%, and tensile modulus 530 cN / dtex.

  Next, this pre-treated aramid fiber bundle (1670 dtex, 1000 fill) is used as a reinforcing material fiber, the fiber is twisted using a twisting machine so that the twist coefficient is 1, and sorbitol polyglycidyl is used as a sizing agent resin component. Ether-type epoxy compound (manufactured by Nagase ChemteX Corporation, “EX614B”), dimethylpyrazole block hexamethylene diisocyanate (manufactured by Baxenden, “Trixene aqua201”, dimethylpyrazole block-HDI trimer) in a solid content of 50% by weight, After immersing in a blending solution having a total solid content of 10% by weight mixed at a ratio of 50% by weight, the mixture was dried at a temperature of 200 ° C. to give 10% by weight of a sizing agent. Then, after dipping in a 10% solids weight aqueous dispersion containing a carboxyl group-containing acrylic-modified bisphenol A type epoxy resin (DIC Corporation, “Dick Fine EN”) as a coating agent, it is dried at a temperature of 200 ° C. Then, the coating agent was treated so that the amount of the coating agent attached to the fiber after drying was 3% by weight, and finally this fiber material was cut into 30 mm to obtain a reinforcing material. The diameter of the obtained treated fiber bundle was 0.5 mm.

  13.9 g of the obtained fiber material for cement reinforcement, 951 g of low heat Portland cement (manufactured by Taiheiyo Cement Co., Ltd.), 220 g of silica fume (manufactured by Elchem AS), fine aggregate (manufactured by Sanei Silica Co., Ltd., “No. 6 silica sand”) 541 g, fine aggregate (manufactured by Sanei Silica Co., Ltd., “Silica Sand SP80”), 193 g of water, and a mortar mixer (manufactured by Marui, MIC-362, capacity: 5 L) at a stirring speed of 140 rpm for about 3 minutes The mixture was kneaded to obtain raw cement (mortar). Table 1 shows the results of evaluating the mortar molded body obtained by curing the raw cement.

[Comparative Example 1]
Instead of using the pretreated aramid fiber bundle of Example 1, twisting is performed using a fiber bundle that is not subjected to surface treatment, and thereafter, in the same manner as in Example 1, treated with a treatment liquid containing an epoxy compound and an isocyanate compound. Went. The location of the epoxy compound was the outer periphery of the fiber bundle. The results are also shown in Table 1.

[Comparative Example 2]
Instead of using the pre-treated aramid fiber bundle of Example 1, twisting is performed using a fiber bundle that is not subjected to surface treatment, and after that, unlike Example 1, only the epoxy compound is contained and the treatment liquid containing no isocyanate compound is used. Was processed. The location of the epoxy compound was the outer periphery of the fiber bundle. The results are also shown in Table 1.

[Comparative Example 3]
In place of using the pretreated aramid fiber bundle of Example 1, fiber bundles that are twisted using a fiber bundle that is not subjected to surface treatment, and that are not subjected to treatment with a treatment liquid containing an isocyanate compound even after Example 1 are used. Got. The results are also shown in Table 1.

Claims (4)

  A fiber bundle made of an aromatic polyamide fiber, the aromatic polyamide fiber is an epoxy pretreated yarn, the fiber bundle is twisted, and the surface thereof is coated with a resin mainly composed of an isocyanate compound. Cement reinforcing fiber material characterized by   The fiber material for cement reinforcement according to claim 1, wherein the resin is a resin containing a polyol or an epoxy compound in addition to the isocyanate compound.   A method for producing a fiber material for cement reinforcement, characterized in that an aromatic polyamide fiber previously treated with an epoxy compound is twisted and then coated with a resin mainly composed of an isocyanate compound.   A concrete or mortar molded body containing the cement reinforcing fiber material according to claim 1 or 2.