JPS6246948A - Nonwoven cloth for reinforcing hydraulic hardened body - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is brittle and! ,,, L cement etc. 7 @
The present invention relates to a nonwoven fabric for reinforcing a cured product.

[Prior art and its problems]

Hydraulic hardened materials, such as Portland cement, have high compressive strength, are nonflammable, durable, and are inexpensive, so they are consumed in large quantities as civil engineering and construction materials. It has the disadvantage of being extremely weak against stress. As a means of compensating for these drawbacks, composites with reinforcing steel are generally used, but problems with steel have surfaced, and problems such as the inability to continuously form secondary products, regardless of whether it is a structural member or not, have arisen. have.

Furthermore, roofing and wall materials are reinforced with asbestos, but as the health hazards of asbestos are becoming clearer, there is a growing demand for alternative materials.

In response to this situation, reinforcement of hydraulically brittle materials with artificial fibers has been studied in recent years, and although some of them have reached the stage of practical application, they have various problems and are sluggish. be. For example, reinforcement is provided by inorganic fibers such as steel fibers and alkali-resistant glass fibers, and short-cut fibers such as polyvinyl alcohol fibers. Although the reinforcing effect varies depending on the fiber material, it is basically difficult to disperse into hydraulic materials, and in addition to lowering the flow value and significantly impairing formability, three-dimensional random orientation Because of this, the reinforcing efficiency is poor, and furthermore, shortcuts cause pull-outs, etc., making it impossible to utilize the inherent strength of the fibers.
The reinforcing effect does not improve. Reinforcement using short-cut fibers has problems in that it deteriorates moldability and workability, does not provide a strong reinforcing effect, and increases costs.

In order to alleviate this problem, attempts have been made to reinforce it with a large number of continuous filaments. Although this method is possible in the laboratory and has a great reinforcing effect in the filament direction, it is difficult to adopt industrially because the molding speed is significantly reduced, continuous molding is difficult, and the cost is high.

Furthermore, many proposals have been made to reinforce the method by stacking multiple layers of net-like materials, but because the layers of net-like materials are piled up, the productivity drops significantly, similar to filament reinforcement, and this method cannot be adopted industrially. In order to increase productivity, a method of reinforcing only the tension side when a bending load is applied with a filament-like material or a net-like material has been proposed, but compared to cement, the Young's modulus of the fiber changes slightly in order. Since the elongation of zumata is υ larger than that of cement, cracks that occur on the tension side may penetrate to the compression side, or a buckling phenomenon may occur on the compression side, making the reinforcing effect less effective than expected.

A method of reinforcing with a nonwoven fabric made of continuous filaments is considered, but known nonwoven fabrics made of continuous filaments are not suitable for reinforcing a hydraulically cured body. This is because spunbond fabrics, ie, nonwoven fabrics made by stacking melt-spun multifilaments using a mechanical method such as traversing and treating with adhesive, are examples of such known typical nonwoven fabrics, but they cannot be used as multifilaments. It is not a nonwoven fabric made of monofilament, in which each single fiber is separated, and the fineness of the monofilament is about 15 dr at most.In addition, a relatively large amount of adhesive is attached to it. Therefore, it is a fine-mesh, high-density nonwoven fabric, and its density is in a much larger range than 0.1 g/am'. It also has low strength. Therefore, it is extremely difficult to uniformly impregnate such a nonwoven fabric with a water mixture of a hydraulic substance such as cement liquid, and molding is impossible. Nonwoven fabrics made from long fibers produced by other methods cannot be molded for the same reason.

On the other hand, known nonwoven fabrics made of short fibers are also unsuitable for reinforcing hydraulic cured bodies. That is, since it is made of short fibers, it may come off from the hardened cement body, resulting in poor reinforcing efficiency. In addition, in order to bring the density within the range of the present invention, crimp or the like must be applied, which significantly reduces the strength and apparent Young's modulus, and from this aspect as well, the reinforcing effect decreases.

The present inventors have arrived at the present invention as a result of intensive research into nonwoven fabrics to solve these problems, that is, to obtain a hydraulically cured material with good moldability, low cost, and excellent performance.

[Failure to solve the problem]

The present invention is a multifilament in which at least a part of single fibers with a tensile strength of 5 g/dr or more are bundled and fixed, and the fineness of the east fixed part is on average lOO~5000 dr, or a multifilament with a tensile strength of 5 g/dr or more. Fineness is 100-5
This is a non-woven fabric for reinforcing a hydraulically cured material having a density of 0.005 to 0.10 g/am'' and made of continuous monofilament fibers of 000 dr.

The first important requirement of the present invention is the fineness of the monofilament or multifilament, 100 to 5.000 dr.
Must. If it is less than 100 dr, the mesh of the nonwoven fabric will be too fine, and the density will further increase, making it impossible to uniformly impregnate the cement liquid, etc. If it exceeds 5000 dr, it will be too rough and the reinforcing effect will be poor. In the case of multifilaments, the fineness of the single fibers constituting the filaments is not particularly limited, but 5 to 50 dr is preferable because it is easy to obtain high strength.

What is important is that in the bundled state of the single fibers, at least a portion, preferably 50% or more, of the single fibers are bound and fixed to each other. If the adhesiveness is less than 50%, impregnation with cement liquid or the like may be difficult and it may not be possible to form a sheet.

The second requirement is the strength of the monofilament or multifilament. Strength as filament is 5g/d
It must be greater than or equal to r. If it is less than 5 g/dr, even if the other requirements of the present invention are met, the reinforcing effect of the hydraulic brittle cured body cannot be obtained.

The third requirement is the density of the nonwoven fabric such as filaments, from 0.005 g/am" to O-10 g/cf.
It has to be ns. If it exceeds 0.1g/cxn3, it will be difficult to impregnate with cement liquid, etc., O-005
If it is less than 1.g/am", it will be too coarse and the proportion (addition of reinforcing fibers) during hydraulic curing will be small and the reinforcing effect will not be enhanced. Preferably O-01g/c-
~0.05Vc-2.

One of the characteristics of the fibers constituting the nonwoven fabric of the present invention is that they are long fibers. Therefore, the contact area between the hardened cement body and one fiber is very large, and the fibers will not be pulled out, so the adhesion between the hardened cement body and the fibers will not be a problem. For this reason, any reinforcing fiber may be used in the present invention as long as it satisfies the requirements of the present invention. For example, polyvinyl alcohol fiber, polyacrylonitrile fiber,
Polyolefin fibers, polyamide fibers,
Examples include organic synthetic fibers such as mid-thread fibers, and inorganic man-made fibers such as alkali-resistant glass fibers, carbon fibers, and steel fibers, with polyvinyl alcohol fibers and polyacrylonitrile fibers being particularly preferred.

An example of the method for manufacturing the nonwoven fabric for reinforcing a hydraulic cured body of the present invention will be described.

In the case of monofilaments of 100 to 5.0 OOdr, they can be used to produce nonwoven fabrics without any special processing, but may be subjected to surface treatment to improve adhesion to cement and the like. In the case of a multifilament with a single fiber fineness of 0.5 to 50 dr, it is first necessary to perform a focusing process. There are few single fibers in the state of non-woven fabric.
□At least a portion, preferably 50% or more, is fixed.
□ However, since the bundling properties differ depending on the type of fiber and the fineness of the single fibers, the bundling agent must be appropriately selected from commercially available bundling agents. Aqueous emulsions such as vinyl acetate, ethylene-vinyl acetate copolymer, acrylic, and epoxy emulsions are preferably used from the viewpoint of focusing properties and workability. Water-soluble polymer sizing agents such as polyvinyl alcohol and modified products thereof can also be used.

A monofilament of 100 to 5000 dr or a multifilament hardened with a sizing agent may be fed onto a wire mesh net moving through a traversing shear soccer or the like to form a nonwoven fabric, then treated with an adhesive and dried. The adhesive may be sprayed on or immersed in an adhesive bath.

Density and thickness can be adjusted by selecting filament fineness, yarn feeding speed, net speed and pressing after adhesive treatment. In addition, especially when the density is desired to be low, a method such as feeding bulky fibers such as crimped fibers at the same time within a range of 30% or less relative to the filament can be taken. Nonwoven fabrics can be manufactured by direct connection to filament manufacturing equipment, or by feeding filaments that have been wound up.

An example of a method for producing a hydraulic cured body reinforced with such a nonwoven fabric will be described. It is also possible to manufacture by direct connection to nonwoven fabric manufacturing equipment, or a non-direct connection method may be used.

In the case of direct connection, a nonwoven fabric having a predetermined width, thickness, and density after adhesive treatment and drying is introduced onto a conveyor, a predetermined amount of a water mixture of a hydraulic substance is supplied through a metering pump, and press rollers are combined as appropriate to produce a predetermined amount. Create a green sheet with hydraulic properties such as thickness and density. In order to provide cover thickness, it is preferable to insert spacers at the top and bottom using wire mesh or the like. After that, it is cut into a suitable length, and if necessary, it is molded and pressed, and then cured in a conventional manner, and if necessary, it is subjected to post-processing such as painting to produce a product. Note that processing such as shaping may be performed before cutting.

In the case of non-direct connection, it is possible to supply the rolled-up nonwoven fabric to the above-mentioned hydraulic hardening body manufacturing equipment, or alternatively, a nonwoven fabric having a predetermined thickness and density can be cut into predetermined lengths and widths. □ After that, it is placed in a mold and a predetermined amount of cement liquid etc. is poured into it, and if necessary, it is shaken and molded, and when it reaches the appropriate hardness, it is removed from the mold and then cured using a conventional method. There is. In this case, the thickness of the hydraulic hardening material is preferably slightly thicker than the thickness of the nonwoven fabric in order to form a cement cover layer on the cement-impregnated nonwoven fabric.

The hydraulic substance of the present invention may basically be any hydraulic inorganic substance, but a typical example is Bo/9) Land Cement. Further, blast furnace cement, fly ash cement, alumina cement, colloid cement, oil well cement, etc. can also be used, as well as Ceracola, magnesia, etc. Of course, these may be used in combination.

It is also possible to replace a part of the hydraulic inorganic substance with another substance depending on the purpose. For example, workability and functionality improvers such as fine aggregate, lightweight materials, expansive materials, wollastonite, mica, sepiolite, and attapulgite can be used.

Although one example of a method for manufacturing a nonwoven fabric made of long fibers with excellent reinforcing properties and a hydraulically cured body reinforced with the nonwoven fabric has been described above, the present invention is not limited to these. However, any method may be used to produce a nonwoven fabric and a hydraulically cured body using the nonwoven fabric within the scope of the claims of the present invention.

〔Effect of the invention〕

As described above, since the nonwoven fabric of the present invention has a suitable density, it has excellent impregnability with cement liquid, etc., and the moldability of a hydraulically cured body using the nonwoven fabric is very good.

In addition, since it is made of high-strength long fibers, all the strength of the fibers is utilized without pulling out in the hydraulically cured body, and the orientation is good, and the thickness of the nonwoven fabric is appropriately selected. The reinforcement effect is very large due to the fact that the fibers exist uniformly in the direction.

Therefore, the nonwoven fabric of the present invention provides a hydraulically cured material that has significantly improved the weak point of extremely low bending and tensile strength without significantly impairing the low cost of conventional hydraulically cured products. I think this is a groundbreaking invention.

Examples 1-2. Comparative Examples 1-2. Reference example 1 degree of polymerization 2000
A 50% aqueous solution of polyvinyl acetate was dry-spun using a conventional method and heat-treated by stretching to obtain a fineness of 50.
A monofilament with a 0 dr strength of 8 g/dr was obtained. One monofilament was fed in layers from an air sucker onto a net with a width of 1.2 m and a speed of 5 m/min, and after spraying ethylene-vinyl acetate emulsion as an adhesive, it was pressed to a thickness of 1.3 cm. A nonwoven fabric made of long fibers was created when dried.

Density 0.03 g/ by changing yarn feeding speed. m' (Example 1) 0,06 g/, - (Example 2) o, 003 g/c
m3 (Comparative Example 1) and 0.12 g/a (Comparative Example 2).

The nonwoven fabric was cut into pieces of 29.5 cm in width and length to be used for reinforcing cement. Next, the width and length are both 39cm, and the thickness is 1.5cm.
After pouring cement mortar (water/cement = 0.35) into a 0.1 cm thick plate-shaped formwork using Portland cement, a non-woven fabric was placed and cement mortar was added to a thickness of 1.5 cm. A vibrator was used to vibrate the mixture to ensure uniform pouring.

After being left at room temperature for 1 day, the mold was demolded and air-dried for 4 weeks, and the physical properties were measured. The results are summarized in Table 1.

It is obvious that in Examples 1 and 2, since the cement liquid is uniformly impregnated into the nonwoven fabric, the moldability is good and the bending strength is significantly improved. In Comparative Example 1, since the density of the nonwoven fabric is too low, the amount of fibers is small and the reinforcing effect is poor. In Comparative Example 2, the density was so high that the cement mortar did not sufficiently penetrate into the nonwoven fabric layer, and a satisfactory molded product could not be obtained.

Note that Reference Example 1 shows a case in which no nonwoven fabric was used at all.

Table-1 Example 10゜03 1.5 0 180
2 0.06 3.0 0. , 240 Comparative Example 1 0.003 0.15 0
802 0.12 6. OX Unmeasurable Examples 3-4. Comparative Examples 3-4 Monofilament fineness was 200 dr (Example 3) 20
00 dr (Example 4), 5Qdr (Comparative Example 3)
Example 1~ except that t was 7000 dr (Comparative Example 4)
A long fiber nonwoven reinforced cement board was prepared in the same manner as in 2, and its physical properties were measured and summarized in Table 2.

Examples 3 and 4 have good cement liquid impregnability and a large reinforcing effect (bending strength holes), but in Comparative Example 3, the fineness of the cement was too high, so the cement 7-tall did not penetrate uniformly into the non-woven layer. ,
A satisfactory sample could not be obtained.

Comparative Example 4 has a poor reinforcing effect because high strength fibers cannot be obtained due to the large fineness, and it is difficult to obtain a uniform nonwoven fabric.

Table-2

Claims (2)

[Claims] (1) A multifilament in which at least a portion of single fibers with a tensile strength of 5 g/dr or more are concentratedly fixed and the fineness of the focused and fixed part is 100 to 5000 dr on average, or a multifilament with a tensile strength of 5 g/dr or more and a fineness of 100 dr. ~5000
Consisting of monofilament continuous fibers with a density of 0.0
05 to 0.10 g/cm^3 nonwoven fabric for reinforcing hydraulic cured bodies. (2) Claims in which the multifilament or monofilament is at least one type of fiber selected from the group consisting of polyvinyl alcohol fiber, acrylic fiber, aramid fiber, polyarylate fiber, polyolefin fiber, and carbon fiber. The nonwoven fabric according to item 1.