JPH072554A - Bundled fiber for reinforcing cement - Google Patents

Abstract

PURPOSE:To produce bundled fiber for reinforcing cement, containing fiber bundled at the time of charging thereof into a cement-based raw material, holding the rigidity without entwining with an aggregate such as gravel and readily separating the bundled fibers into single fiber or several fibers in a bundled state by an external force due to stirring after charging thereof. CONSTITUTION:An alkali metallic salt of an 8-18C n-alkyl phosphate (an oiling agent) in an amount of 15-75wt.% based on the fiber weight is applied to fiber, obtained by melt spinning and drawing and having 0.5-15 denier single fiber size in a tow state and the resultant fiber in the bundled state is then short-cut. Thereby, this fiber for reinforcing cement in which about >=100 short-cut fibers are joined and bundled into a separable state with the oiling agent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bundled fiber for reinforcing a cement product as a whole, and more particularly to a bundled fiber for cement reinforcement effective as a reinforcing fiber for mortar. Is.

[0002]

2. Description of the Related Art Conventionally, it has been proposed to use various inorganic fibers and synthetic fibers as cement reinforcing fibers in place of asbestos. For example, JP-A-49-98424 and JP-A-4
9-104917, JP-A-49-104918, JP-A-61-86452, JP-A-62-1.
No. 71952 discloses the use of glass fibers, polyester fibers, vinylon fibers, polypropylene fibers, aromatic polyamide fibers and acrylic fibers. Further, as the focusing fiber, Japanese Patent Publication No. 53-37957,
JP-B-63-59980, JP-A-52-8912
No. 2, Japanese Patent Laid-Open No. 4-149057, Publication No. 4-
No. 502142 discloses glass fiber, vinylon fiber,
The use of polyolefin fibers is taught.

[0003]

As described above, many fibers for cement reinforcement have been heretofore known. However, when a thin monofilament is used as a reinforcing fiber for mortar, etc. Is too soft and clings to aggregates such as jari and cannot sufficiently exert its reinforcing effect. Therefore, attempts have been made to increase the rigidity by making the fibers thicker or in a bundled state to prevent clinging to aggregates such as jars. However, in the case of a single fiber having a large fineness, the ratio of the fiber occupying a part of the cement becomes large, and the part where the fiber exists conversely becomes a defect. Further, in the conventional bundled fiber, generally, in the state of a multifilament yarn, single fibers are bundled and joined with a sizing material or the like to make a short cut.Therefore, the binding force thereof is quite strong, and it is mixed into cement. Even because it is difficult to separate into single fibers, the proportion of fibers in a part of the cement is large as in the case of single fibers with the above-mentioned large fineness,
On the contrary, the part where fibers are present becomes a defect. In addition, the method of obtaining a short cut in the state of the joined multifilament yarn is poor in productivity and costly.

The object of the present invention is, in particular, in the mortar field, when the fibers are put into the cement-based raw material, the fibers are bundled and have rigidity, and at the time of putting the fibers, they do not cling to aggregates such as jari and Provided is a cement-reinforced bundled fiber in which the bundled fiber is easily separated into single fibers or several fibers in a bundled state by an external force due to subsequent stirring.

[0005]

The present invention has solved the above-mentioned problems by adhering an appropriate amount of a surfactant to the surface of a fiber to bond the fibers together with a weak force to form a bundled fiber. That is, the bundled fibers for cement reinforcement of the present invention,
About 100 or more of 0.5 to 15 denier short cut fibers having 15 to 75% by weight of normal alkyl phosphate alkali metal salt having 8 to 18 carbon atoms adhering to the fiber weight are bonded and bundled in a separable state. It is characterized by being present.

In another preferred cement-reinforced fiber bundle of the present invention, an alkali metal salt of normal alkyl phosphate having 8 to 18 carbon atoms is attached in an amount of 15 to 75% by weight based on the weight of the fiber. About 100 or more short cut fibers of 0.5 to 15 denier to which 3 to 35% by weight of polyvinyl alcohol are attached are bonded and bundled in a separable state.

Furthermore, the bundled fibers for cement reinforcement are polypropylene or poly (4-methylpentene-1) polyolefin having excellent alkali resistance, and 2 to 20 calcium carbonate fine powder having an average diameter of less than 1 μm.
2 to 2 of fine particles of calcium carbonate having an average diameter of less than 1 μm in a single fiber made of a resin containing by weight, polypropylene or polyolefin of poly-4-methylpentene-1.
It is a core-sheath type composite fiber having 0% by weight of a resin as a sheath component and polypropylene or polyolefin of poly-4-methylpentene-1 as a core component.

The polyolefin resin forming the fiber is a normal polypropylene resin, poly-4-methylpentene-1.
Although it may be a resin, especially as a polypropylene resin, Q
Value (Q: weight average molecular weight / number average molecular weight ratio) of less than 5, preferably 4 or less, boiling n-heptane insoluble matter (H
I: wt%) is 97% or more, preferably 98% or more, and the isotactic pentat fraction (IPF: mol%) is 94% or more, preferably 96% or more. A polypropylene resin having a Q value of less than 5 has good heat stretchability, and a polypropylene resin having an HI of 97% or more and an IPF of 94% or more has few low crystalline components and is excellent in stereoregularity. Is improved and fiber strength is increased, and a fiber having excellent rigidity can be obtained.

The normal alkyl phosphate alkali metal salt used in the present invention is normal alkyl phosphate potassium or normal alkyl phosphate sodium, for example, octyl phosphate potassium or sodium having 8 carbon atoms, decyl phosphate potassium or sodium having 10 carbon atoms, carbon C 12 lauryl phosphate potassium or sodium, C 13 tridecyl phosphate potassium or sodium, C 14 myristyl phosphate potassium or sodium, C 16 cetyl phosphate potassium or sodium, C 18 stearyl phosphate potassium or sodium For example, when the number of carbon atoms of the alkyl is 7 or less, the effect of the present invention is difficult to obtain, and when the number of carbon atoms is 19 or more, Deposition process stable aqueous solution as an active agent to be hardly fibers obtained hardly.

The normal alkyl phosphate alkali metal salt may be either a monoalkyl ester or a dialkyl ester. The preferable amount of the normal alkyl phosphate alkali metal salt attached to the fiber is 15 to 75% by weight with respect to the weight of the fiber. If it exceeds the above range, the fibers have sufficient sizing property, but the fibers are less likely to come apart in the process of mixing with the cement.

The normal alkyl phosphate alkali metal salt may be attached to the fiber by adding the surfactant at any stage of the fiber production process, but preferably after the drawing process. The application method may be any of a dipping method, a spray method, and a coating method.

If it is desired to make the fiber more rigid, polyvinyl alcohol may be adhered in an amount of 3 to 35% by weight to the fiber to which the normal alkyl phosphate alkali metal salt is adhered. If the adhered amount is less than 3% by weight based on the weight of the fiber, the obtained fiber cannot obtain the hardness, and if it exceeds 35% by weight, the fibers are too strongly adhered to each other and the short fibers are mixed in the cement slurry. Separability into As the applying method, the dipping method, the spraying method, and the coating method can be mentioned as in the above. At this point, if the unit of bundle of single fibers is large, for example, if it is a band in the state of tow, it is made into a narrow width of about 2 to 8 mm by a slitter,
It is advisable to cut it into 3 to 15 mm to make a large number of bundled fiber pieces. When the short cut bundled fibers are immersed in a PVA aqueous solution in order to enhance the focusing and bonding strength, a compressed air nozzle is sprayed before the PVA aqueous solution is completely dried to bundle the fibers with an appropriate size (width 2 to 8 mm). It is good to separate into fiber pieces. The number of fibers in one bundled fiber piece is random, but about 100 to 10,000 fibers are practically desirable.

The short cut bundled fibers of the present invention can be applied to the reinforcement of ordinary Portland cement, blast furnace cement, silica cement, alumina cement, etc.
It can also be used when using hemihydrate gypsum, dihydrate gypsum and slag, or when these are mixed with the above cement,
It can be applied to any method of manufacturing cement molded products such as natural curing, steam curing, autoclave curing, etc. by wet papermaking method, pouring method and extrusion molding method.

[0014]

The cement-reinforcing fiber of the present invention in which single fibers are bundled with a weak adhesive force by a surfactant or polyvinyl alcohol is easily separated into single fibers or a few bundled fibers when mixed with cement material and stirred. ,
Good dispersion due to the action of moderate rigidity and surfactant,
It greatly contributes to the improvement of impact and bending strength of cement products obtained by the dry method or the wet method. Furthermore, the bundled fiber obtained by uniformly adding an appropriate amount of calcium carbonate to the whole fiber or the sheath component of the core-sheath type composite fiber improves the affinity with cement and disperses better, and the impact strength of the cement molded body is improved. Bending strength can be improved without damage.

[0015]

【Example】

[Example 1] As a fiber-forming resin, the Q value of the resin was 3.
5, a polypropylene resin having an HI of 98%, an IPF of 97%, and an MFR (melt flow rate; g / 10 minutes, according to JIS-K-7210) of 15 was used. The fiber has a core-sheath type composite structure (core / sheath = 6/4) with a fineness of 2 denier, and the core-sheath is made of the same resin. The sheath component is pretreated with a metal soap having an average particle size of 0.5 μm. Calcium carbonate fine powder prepared by kneading and adding 8% by weight to 275 ° C
After melt-spinning at a temperature of 10%, stretching is performed, 30% by weight of an oil agent which is a potassium salt of lauryl phosphate is adhered, then bundled, dried and cut into a length of 6 mm to give about 2
A large number of bundled fiber pieces in a state where 100 to 20,000 short fibers were bundled were formed.

The form of the above-mentioned convergent fiber piece is a flat rectangular small piece having a converging width of about 2 to 8 mm where a large number of short cut fibers are joined in parallel and are easily separated when an external force is applied. It has the shape of.

Next, 400 g of ordinary Portland cement,
When 100 g of silica sand and 7.5 g of the above-mentioned focused fibers (focused fiber piece group) were sequentially added and mixed by stirring (dry mixing), the focused fibers were finely separated into about 1 to 10 fibers in Portland cement and silica sand. It was evenly dispersed.
After that, 50% by weight of tap water was added to the mixture of the cement-based raw materials and mixed by stirring (wet mixing). Even in the state after the wet mixing, the bundled fibers finely separated maintained the dispersed state during the dry mixing without floating or exhibiting the state of fiber balls.

Example 2 15 wt% of an oil agent (lauryl phosphate potassium salt) was adhered to the melt-spun fiber in Example 1 and then bundled, dried and cut into a length of 6 mm, and then bundled into a large number of bundles. Made into a fiber piece. Then, when the bundled fibers were mixed with Portland cement and silica sand in the same manner as in Example 1 and stirred, most of the bundled fibers were further finely divided (about 1 to 5 fibers) to be separated from the Portland cement and silica sand. Were almost evenly dispersed in the. The dispersed state was maintained even after wet mixing with the addition of water.

[Example 3] The adhered amount of the oil agent in Example 2 was set to 75% by weight to form a bundled fiber.
When this bundled fiber was dry mixed with Portland cement and silica sand in the same manner as above, the bundled fiber had a fiber number of 1-2.
It was separated into about 5 pieces and was almost evenly dispersed in Portland cement and silica sand. The dispersed state was maintained even after wet mixing with the addition of water.

[Comparative Example 1] The oil agent adhesion amount of Example 1 was 5
A bundled fiber was prepared in the same manner as in Example 1 except that the weight percentage was changed. However, the bundled bondability was poor, and thus it was difficult to separate it into small pieces before use, and the obtained bundled fiber had a rigidity in a single fiber state. However, when the fibers were dry mixed with Portland cement and silica sand, the bundled fibers were easily separated into single fibers, but the separated single fibers were entangled with each other, which was not suitable for mortar cement products. .

[Example 4] The short cut fibers to which the potassium lauryl phosphate salt of Example 1 was adhered were dipped in an aqueous solution of polyvinyl alcohol to further add 5% by weight to the fiber surface.
Polyvinyl alcohol was adhered, and after semi-drying, compressed air was blown to separate into the form of a bundle of fiber bundles, which was dried to obtain a bundle of fibers for cement reinforcement.

Next, 20 g of the above-mentioned bundled fibers, 1200 g of ordinary Portland cement, 800 g of silica sand, and 20 g of methylcellulose were sequentially added and dry-mixed to obtain a cement-based raw material. After that, tap water (20% by weight of water relative to the cement-based raw material) was added to the cement-based raw material, wet-mixed, and extrusion-molded by an extruder. About 10 pieces were separated and uniformly dispersed, and the dispersion state was maintained even by wet mixing, and a high quality cement molded product was obtained.

[Comparative Example 2] In the above-mentioned Example 4, the adhered amount of polyvinyl alcohol was set to 50% by weight to form a bundled fiber. However, since the binding strength of the bundled fibers is too strong, the separability of the bundled fibers is poor at both dry mixing and wet mixing, and many bundles of 100 or more fibers are bundled. .

[0024]

As described above in detail, the bundled cement reinforcing fiber of the present invention has 15 to 75% by weight of the normal alkyl phosphate alkali metal salt having 8 to 18 carbon atoms based on the weight of the fiber. Since about 100 or more short cut fibers of 0.5 to 15 denier are bonded and bundled in a separable state, they are easy to handle and easy to put into the cement raw material, and then put into the hopper of the extruder. Even if it is automatically supplied, it can be smoothly sent out by a predetermined amount. Moreover, since it is easily separated into single fibers or a small number of fiber bundles when dry-mixed, it is uniformly dispersed in the cement,
Further, since this dispersed state is maintained even during wet mixing, both impact strength and bending strength of cement products such as mortar and cement board can be improved as compared with the conventional case.

Furthermore, by forming a bundle of fibers by adding calcium carbonate to a highly crystalline polypropylene resin, a bundle of fibers for cement reinforcement having excellent alkali resistance and good affinity with cement can be obtained. The bending strength of the cement product can be further improved.

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location D06M 13/292

Claims (4)

[Claims] 1. The normal alkyl phosphate alkali metal salt having 8 to 18 carbon atoms is 15 to 75 with respect to the weight of the fiber.
A bundled cement-reinforcing fiber, characterized in that about 100 or more short cut fibers of 0.5 to 15 denier adhering in weight% are joined and bundled in a separable state. 2. The normal alkyl phosphate alkali metal salt having 8 to 18 carbon atoms is 15 to 75 with respect to the weight of the fiber.
% By weight, and polyvinyl alcohol of 3 to 35
A bundled cement-reinforcing fiber characterized in that about 100 or more short cut fibers of 0.5 to 15 denier adhering to each other in a weight percentage are bonded and bundled in a separable state. 3. The bundled fibers are made of polypropylene or polyolefin of poly 4-methylpentene-1 and 2 to 2 of calcium carbonate fine powder having an average diameter of less than 1 μm.
A single fiber made of a resin containing 20% by weight, polypropylene or a polyolefin such as poly-4-methylpentene-1 and 2 pieces of calcium carbonate fine powder having an average diameter of less than 1 μm.
[Claim 1] or [Claim 2], which is a core-sheath type composite fiber having a resin containing 20% by weight to 20% by weight as a sheath component and polypropylene or a polyolefin such as poly-4-methylpentene-1 as a core component. Bound cement reinforcing fibers as described in. 4. The bundled fibers have a Q value (Q: weight average molecular weight / number average molecular weight ratio) of less than 5, a boiling n-heptane insoluble matter (HI: weight%) of 97 <HI <100,
[Claim 1] or [Claim 2], which is a highly crystalline polypropylene having an isotactic pentad fraction (IPF: mol%) of 94 <IPF <100.
Alternatively, the bundled cement reinforcing fiber according to claim 3.