JPH0672038B2 - Fiber for cement reinforcement - Google Patents

Description

TECHNICAL FIELD The present invention relates to a fiber for cement reinforcement having excellent bending strength in a fiber-reinforced cement composite material.

[Prior art]

In recent years, fire resistance, fire resistance,
The demands for earthquake resistance and the like are becoming more severe, and along with that, the performance of the reinforcing fiber is being improved.
In the conventional reinforcing method using fibers, sufficient improvement in performance has not been realized yet.

The conventional reinforcement methods are roughly classified into the following two. One of them is a method in which a chipped strand obtained by cutting a fiber into a required length is dispersed in cement matrix to reinforce it. The other is a method of reinforcing continuous fibers by arranging them in cement.

[Problems to be solved by the invention]

However, any of the conventional methods has a problem that the adhesion between the cement and the reinforcing fiber is poor and sufficient performance cannot be obtained.

[Means for solving problems]

Therefore, as a result of intensive studies to solve the conventional problems, the present inventors have found that the adhesion between the cement and the reinforcing fiber is improved by providing the reinforcing fiber with a coating layer having a specific composition. Found and arrived at the present invention.

That is, an object of the present invention is to provide a cement-reinforcing fiber having improved adhesion between cement and reinforcing fiber and having excellent bending strength.

And, the object is achieved by a fiber for cement reinforcement characterized by being obtained by impregnating an organic or inorganic fiber with a thermosetting resin, coating it with a rubber solution or a rubber latex, and curing it. To be done.

Hereinafter, to describe the present invention, the organic or inorganic fiber used in the present invention is not particularly limited, for example, as the organic fiber, nylon, polyester, rayon,
Further, aromatic fibers such as aramid are used, and as the inorganic fibers, steel, glass fiber, carbon fiber, graphite fiber and the like are used. Among these, those having a tensile strength of 150 kg / mm ² or more and a Young's modulus of 10 ton / mm ² or more are preferable. The fibers may be pretreated with a surface treatment and a finishing agent.

The surface treatment includes gas phase oxidation, liquid phase oxidation, or a method using an oxidizing agent, and the treatment with a finishing agent includes a sizing agent, a lubricant,
Epoxy type, acrylate type, used as a softening agent,
Known compounds such as polyethylene, polybutene, polyester, polyurethane and silicone may be used alone or in combination.

Next, as the thermosetting resin used in the first treatment in the present invention, a known one is used regardless of whether it is water-soluble or water-insoluble.
For example, there are epoxy compounds, unsaturated polyester, polyimides, etc., ethylene glycol, glycerol,
Reaction products of polyhydric alcohols such as sorbidol and propylene glycol with halogen-containing epoxides such as epichlorohydrin, and reaction products of polyhydric phenols such as resorcinol, hydroquinone, bisphenol A, and catechol with the halogen-containing epoxides. The thing etc. can be mentioned. Such thermosetting resin is soluble in water,
Alternatively, it is used as an emulsion-dispersed aqueous solution or a solution using an organic solvent.

Next, the type of rubber used in the second treatment of the present invention includes, for example, natural rubber, styrene butadiene rubber, acrylonitrile rubber, acrylic ester copolymer, chloroprene rubber, EPDM, butyl rubber, chlorosulphonated polyethylene, and fluorine. Known materials such as rubber and polyurethane rubber are used, and they are used in a suspension system in which the above-mentioned rubber solid is dissolved, or a water emulsion emulsion polymerization method, or a polymer obtained by another polymerization method as an emulsifier. A latex prepared by re-emulsifying into a water emulsion system is used, but it is preferable to use the latex because the desired rubber solid content concentration can be selected. Further, the rubber solution or the rubber latex is mixed with a reinforcing material such as a filler, or a vulcanizing agent, and a vulcanization accelerator, if necessary.
It may be dispersed.

As a method of subjecting the fiber to the first treatment and the second treatment,
After continuously pulling out the fiber bundle or filament and immersing it in the first bath of thermosetting resin liquid via a roller or the like,
Usually, it is cured through a heat treatment tank, and then, through a roller or the like, it is immersed in a rubber solution or a second bath of rubber latices, cured through a heat treatment tank and wound up, or a continuous impregnation treatment, or cut into a predetermined length. Any of the batch-type impregnation treatment methods in which the fiber bundle or filament is treated in the same procedure as the step of the continuous impregnation treatment method may be used.

Incidentally, in the present invention, the first treatment with a thermosetting resin may be carried out, and the second treatment may be carried out continuously in the uncured state of the resin, but it is preferable that at least the resin is in a semi-cured state by the second treatment. It is convenient to apply the above.

At that time, the thermosetting resin liquid and the rubber solution or the rubber latex usually coats the entire fiber, but may be a partial coat that does not impair the effects of the present invention. The amount of the thermosetting resin attached to the fibers is preferably 50 to 200% by weight.

If the resin adhesion amount is too large, cohesive failure due to uneven adhesion tends to occur, while if the resin adhesion amount is too small, the original tensile strength of the fiber cannot be utilized. The amount of the rubber solid content attached to the fibers is 10 to 200% by weight, preferably 50 to 100% by weight. If the amount of rubber adhered is too large, cohesive failure of the rubber layer tends to occur, while if the amount of rubber adhered is too small, adherence to cement is reduced.

Next, the heat treatment temperature for heat treating and curing the coated thermosetting resin and rubber is usually 70 ° C. or higher after the first treatment,
Do it for about 30 minutes at 120 ℃ or less. When it is desired to further increase the fiber strength, the heating may be performed at 150 ° C or higher and 200 ° C or lower for about 1 hour.

After the second treatment, it is preferably performed at 100 ° C. or higher and 200 ° C. or lower for about 10 to 50 minutes. In both the first treatment and the second treatment, if the heat treatment temperature is too low, the resin and the rubber are
It does not cure sufficiently and the original strength of the fiber cannot be obtained. On the other hand, if the heat treatment temperature is too high, the resin and rubber are deteriorated and deteriorated, and the adhesion to the cement is reduced.

When the fiber subjected to the above treatment is used for cement reinforcement, there is no restriction on the fiber form and construction method as in the prior art, depending on the manufacturing method of the reinforced cement material, a short fiber shape, a long fiber (strand) shape, It can be used in various forms such as a sheet form, a non-woven fabric form and a woven form, and can be applied by various methods such as a direct spray method, a premix method, an impregnation method (or a handlay up method) and a papermaking method.

Further, it can be mixed with various hydraulic cements such as Portland cement, blast furnace cement, alumina cement and calcium silicate to produce fiber-reinforced cement materials of various shapes such as plate, tube and column. The amount of fiber to use is determined to obtain the desired strength properties.

Usually, 0.5 to 5 parts by weight is desirable for 100 parts by weight of dry weight of cement. Next, cement matrix is obtained by mixing cement and water by hydration reaction, the water required for hydration is usually 20 to 70 parts by weight, relative to 100 parts by weight of dry weight of cement, In order to increase the strength of the cement structure as much as possible, it is preferable to mix 30 to 45 parts by weight of water. Furthermore, as aggregate, sand, silica sand, etc. are cemented.
You may use "mortar" which mix | blends 50-200 weight part with respect to 0 weight part.

〔The invention's effect〕

It was confirmed that the fiber-reinforced cement material thus obtained has excellent bending strength, which is not found in conventional reinforced cement materials.

In addition, the treatment of the present invention has an anticorrosion effect against water and alkalinity of cement, and therefore has an advantage that steel and glass fibers can be used.

By inferring the reason why excellent bending strength is exhibited by the present invention, by coating the rubber layer on the outside of the fiber impregnated with the thermosetting resin, the rubber layer disperses the bending stress and prevents the destruction of the resin layer. Therefore, it is considered that the strength of the fiber is maintained and the bending strength of the cement composite is increased.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to the following Examples unless it exceeds the gist.

Example 1 Pitch-based carbon fibers having a tensile strength of 200 kg / cm ² and a Young's modulus of 40 ton / mm ² (length: 30 cm) were impregnated with a methyl ethyl ketone solution containing a 50% concentration of epoxy resin, and then 80
Further, the resin was cured by being dried at 150 ° C. for 20 minutes and further heat-treated at 150 ° C. for 20 minutes. Subsequently, in advance, a vulcanizing agent and a vulcanization accelerator were mixed and coated with 40% solid content styrene butadiene latex (manufactured by Nippon Zeon Co., Ltd.), followed by drying at 80 ° C. for 20 minutes, Further, the rubber was cured by heat treatment at 150 ° C. for 20 minutes. The amounts of resin and rubber attached to the carbon fibers were 135% by weight and 41% by weight, respectively. The obtained carbon fiber bundle was cemented with a cement 10
Ten carbon fiber bundles were arranged in a cement matrix composed of 55 parts by weight of water and 160 parts by weight of sand with respect to 0 parts by weight at regular intervals. Next, air curing (temperature 20
C., relative humidity 65%), and a carbon fiber reinforced cement material was obtained after 7 days. The obtained carbon fiber reinforced cement material was subjected to a bending test under the following conditions.

Specimen size: length 32 cm, width 4 cm, thickness 2 cm span span: 26 cm cover thickness: 0.3 cm 3-point bending test method: average value of 3 specimens The bending properties are shown in Table 1.

(Example 2) Using the same carbon fiber as in Example 1, pretreatment was performed with a 2% aqueous epoxy resin solution (polyethylene glycol diglycidyl ether). The amount of the epoxy resin deposited was about 1% by weight based on the carbon fiber.

The physical properties of the carbon fiber reinforced cement material obtained in the same manner as in Example 1 are shown in Table 1 below.

The amount of styrene-butadiene rubber attached was 88% by weight based on the carbon fiber.

(Example 3) Using the same carbon fiber as in Example 1, a 2% epoxy resin emulsion (a treatment liquid obtained by adding a surfactant to the reaction product of epichlorohydrin and bisphenol A to emulsify and disperse it) Was pre-treated with. The amount of the epoxy resin attached was 1.5% by weight based on the carbon fiber. Hereinafter, the physical properties of the carbon fiber-reinforced cement material obtained in the same manner as in Example 1 will be first described.
Shown in the table.

The amount of styrene-butadiene rubber attached was 95% by weight based on the carbon fiber.

Comparative Example 1 The physical properties of the carbon fiber reinforced cement material obtained in the same manner as in Example 1 except that the same carbon fiber as in Example 1 was not treated with a rubber solution or a rubber latex are shown in Table 1. It was shown to.

The amount of the epoxy resin attached was 105% by weight based on the carbon fiber.

(Comparative Example 2) The same carbon fiber as in Example 1 was used, and was obtained in the same manner as in Example 1 except that the vulcanizing agent and the vulcanization accelerator were not mixed and dispersed in the rubber solution or the rubber latex. The physical properties of the carbon fiber reinforced cement material are shown in Table 1.

The amounts of the epoxy resin and styrene-butadiene rubber attached were 89% by weight and 76% by weight, respectively, with respect to the carbon fiber.

Claims (1)

[Claims] 1. A cement-reinforcing fiber, which is obtained by impregnating an organic or inorganic fiber with a thermosetting resin, coating it with a rubber solution or a rubber latex, and curing it.