JPH07330398A - Fiber for reinforcement of cement and its production - Google Patents

Abstract

PURPOSE:To produce a fiber for reinforcement of cement, excellent in heat resistance, chemical resistance, steam resistance and lightweight properties and capable of curing at high temperatures by melt-spinning a composition containing 4-methyl-1-pentene-based polymer and a specified graft modified PP and subsequently stretching it. CONSTITUTION:A modified PP is synthesized by conducting a graft copolymerization reaction of 0.01 to 20wt.% one or more kinds of modification monomers selected from unsaturated carboxylic acids (derivatives) on PP having 0.89 to 0.91g/cm<3> density and 0.1 to 30g/10-min melt flow rate (ASDM-D-1238-65, 230 deg.C). With 2 to 30 pts.wt. the resultant modified PP, 100 pts.wt. 4-methyl-1- pentene-based polymer is blended to obtain a modified PP composition having 20 to 250g/10min melt flow rate and 0.89 to 0.91g/cm<3> specific gravity. This composition is melt spun at 250 to 350 deg.C and subsequently stretched by a factor of 2 to 10 times at 80 to 150 deg.C, thus the objective fiber for reinforcement of cement, having 0.5 to 50 denier fiber diameter and 1 to 100mm length is produced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cement-reinforcing fiber and a method for producing the same, and in particular, in the process for producing a slurry-paper-making process of a fiber-reinforced cement plate, the reinforcing fiber does not float in the supernatant liquid part, The present invention relates to a cement-reinforcing fiber that can be dispersed to stably produce a high-quality fiber-reinforced cement board, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, asbestos is used as a reinforcing fiber in a cement board used as a building board material.
However, in recent years, the use of asbestos has been restricted, and fiber-reinforced cement boards using reinforcing fibers made of polypropylene, poly-4-methyl-1-pentene, etc. have been manufactured instead of asbestos. There is. In particular, a fiber made of 4-methyl-1-pentene polymer is
It is suitable as a reinforcing fiber because it has the heat resistance, chemical resistance, steam resistance and light weight which are the characteristics of the 1-pentene polymer itself.

By the way, a fiber-reinforced cement board is produced by making a papermaking board by making a slurry prepared by dispersing a mixture containing reinforcing fibers and cement as main components in water, and curing the papermaking board. To be done.

[0004]

However, in the process of producing a fiber-reinforced cement board by using a fiber made of polypropylene or poly-4-methyl-1-pentene instead of asbestos as a reinforcing fiber, the reinforcing fiber and the cement are mixed with each other. In the slurry in which the composition as the main component is dispersed in water, the reinforcing fibers are not sufficiently dispersed in the slurry, and a part thereof is separated from the slurry, and the reinforcing fibers float in the supernatant liquid part of the slurry. is there. Therefore, these reinforcing fibers are accumulated and accumulated in equipment such as piping lines and pumps for collecting the supernatant liquid, causing clogging or failure, and the obtained fiber-reinforced cement plate has a required amount of reinforcing fibers. It becomes difficult to manufacture a fiber-reinforced cement plate that accurately contains, and the quality of the obtained fiber-reinforced cement plate is not stable, and there is a problem that the quality deteriorates.

Therefore, the first object of the present invention is to provide the 4-methyl-1-pentene polymer itself with the heat resistance, chemical resistance, steam resistance and light weight characteristics, and to cure at high temperature. It is possible, without the reinforcing fibers floating in the supernatant liquid part in the manufacturing process of slurry papermaking of the fiber reinforced cement plate,
It is an object of the present invention to provide a cement-reinforcing fiber that can be sufficiently dispersed in a slurry to stably produce a good-quality fiber-reinforced cement board.

A second object of the present invention is to provide a method capable of producing the cement reinforcing fiber.

[0007]

In order to solve the above-mentioned problems, the present invention provides a 4-methyl-1-pentene polymer,
A modified polypropylene, which is graft-modified with at least one modified monomer selected from unsaturated carboxylic acids and derivatives thereof and has a graft amount of 0.01 to 20% by weight, and a melt flow rate of 20 to 250 g. / 1
It is intended to provide a cement-reinforcing fiber comprising a modified polyolefin composition of 0 minutes.

The present invention also provides, as the method for producing the modified polyolefin fiber, grafting with a 4-methyl-1-pentene polymer and at least one modified monomer selected from unsaturated carboxylic acids and their derivatives. Modified polypropylene having a graft amount of 0.01 to 20% by weight and a melt flow rate of 20 to 25.
The modified polyolefin composition, which is 0 g / 10 minutes, is
The present invention also provides a method for producing a fiber for cement reinforcement, which comprises a step of melt-extruding at a temperature of 0 ° C to 350 ° C, spinning, and then stretching at a draw ratio of 2 times or more.

The cement reinforcing fiber of the present invention (hereinafter referred to as the "fiber of the present invention") and the method for producing the same will be described in detail below.

The fiber of the present invention comprises a 4-methyl-1-pentene polymer and a modified polyolefin composition containing modified polypropylene as a main component.

The 4-methyl-1-pentene polymer which is the main component of the modified polyolefin composition is 4-methyl-1.
-A polymer containing pentene as a main component, for example, 4-
Examples thereof include a homopolymer of methyl-1-pentene, or a copolymer of 4-methyl-1-pentene and another compound copolymerizable with 4-methyl-1-pentene. 4-
As other compounds copolymerizable with methyl-1-pentene, for example, ethylene, propylene, 1-butene, 1-
Examples include α-olefins having 2 to 20 carbon atoms such as hexene, 1-octene, 1-decene, 1-tetradecene and 1-octadecene. One or more of these other compounds may be contained in the 4-methyl-1-pentene-based polymer. The content of 4-methyl-1-pentene in the 4-methyl-1-pentene-based polymer is usually 8
It is 5 mol% or more.

The modified polypropylene which is the main component of the modified polyolefin composition is obtained by graft-copolymerizing polypropylene with at least one modifying monomer selected from unsaturated carboxylic acids and their derivatives.
Polypropylene, which is the main component of modified polypropylene, has a density of 0.89 to 0.91 g / cm ³ and a melt flow rate (ASTM D1238-65, 230 ° C.) of 0.1.
It is a propylene homopolymer or a copolymer of propylene and α-olefin that is ˜30 g / 10 min. Examples of the α-olefin include ethylene, 1-butene, 1-pentene, 1-hexene, and 3-methyl-1-.
Examples thereof include pentene, and these may be used alone or in combination of two or more. When polypropylene is a copolymer containing α-olefin, the content of α-olefin is 10 mol% or less, preferably 7 mol% or less.

Examples of the unsaturated carboxylic acid which is a modified monomer graft-copolymerized with the modified polypropylene include (meth) acrylic acid, maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid, citraconic acid and crotonic acid. , Isocrotonic acid, nadic acid (8-endocis-bicyclo [2.2.1] hept-5-ene-2,3-
Dicarboxylic acid) and the like. Examples of these derivatives include acid halides, acid amides, acid imides, acid anhydrides and ester compounds of these unsaturated carboxylic acids, and specific examples thereof include maleenyl chloride, maleimide and maleic anhydride. Acid, citraconic anhydride, dimethyl maleate, glycidyl maleate and the like can be mentioned.
The graft copolymerized units in the modified polypropylene may contain one kind of these or a combination of two or more kinds thereof.

The content of these modified monomers in the modified polypropylene, that is, the graft amount, is excellent in dispersibility in the slurry, and a cement-reinforcing fiber having excellent compatibility with the non-modified polyolefin is obtained. It is usually 0.01 to 20% by weight in that the occurrence of yarn breakage is small.
The amount is about 0.01 to 15% by weight.

As a method of producing a modified polypropylene by graft-copolymerizing a modified monomer selected from the unsaturated carboxylic acid or its derivative with polypropylene, various conventionally known methods can be mentioned. For example, a method of melting polypropylene and then adding a modifying monomer for graft copolymerization, a method of dissolving polypropylene in a solvent and adding a modifying monomer for copolymerization, and the like can be mentioned. In any method, in order to efficiently graft-copolymerize the modified monomer, it is preferable to react in the presence of a radical polymerization initiator.

The reaction of this graft copolymerization is usually 60
It can be performed at a temperature of ˜350 ° C.

The radical polymerization initiator used is
Examples thereof include organic peroxides, organic peresters, and other azo compounds. Among these radical polymerization initiators, dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di (t
Dialkyl peroxides such as ert-butylperoxy) hexyne-3,2,5-dimethyl-2,5-di (tert-butylperoxy) hexane and 1,4-bis (tert-butylperoxyisopropyl) benzene are preferred. These may be used alone or in combination of two or more.

The amount of the polymerization initiator used is usually about 0.001 to 1 part by weight per 100 parts by weight of polypropylene.

Examples of the solvent used in the graft copolymerization reaction include hexane, heptane, octane,
Aliphatic hydrocarbons such as decane, dodecane, tetradecane;
Alicyclic hydrocarbons such as methylcyclopentane, cyclohexane, methylcyclohexane, cyclooctane, cyclododecane; benzene, toluene, xylene, ethylbenzene, cumene, ethyltoluene, trimethylbenzene,
Aromatic hydrocarbons such as cymene and diisopropylbenzene;
Examples thereof include halogenated hydrocarbons such as chlorobenzene, bromobenzene, o-dichlorobenzene, carbon tetrachloride, trichloroethane, trichloroethylene, tetrachloroethane and tetrachloroethylene, and kerosene which is a mixture of aliphatic hydrocarbons. These may be used alone or in combination of two or more. The ratio of the solvent used is usually 100 with respect to 100 parts by weight of polypropylene.
〜100,000 parts by weight, preferably 200-100
It is about 000 parts by weight.

The temperature of the graft copolymerization reaction is usually 10
It is about 0 to 250 ° C, preferably about 110 to 200 ° C, and the reaction time is usually about 15 to 600 minutes, preferably about 30 to 360 ° C.

The content ratio of the 4-methyl-1-pentene polymer and the modified polypropylene in the modified polyolefin composition is 2 to 30 parts by weight of the modified polypropylene with respect to 100 parts by weight of the 4-methyl-1-pentene polymer. Is preferable, and further mixed in a cement board to obtain a high-strength cement board, and in order to improve productivity, high temperature curing at a curing temperature of 160 to 190 ° C. is possible, The proportion is preferably 2 to 20 parts by weight.

Further, the modified polyolefin composition may contain other compounding agents, if necessary, in addition to the 4-methyl-1-pentene polymer and the modified polypropylene. As other compounding agents, for example, heat resistance stabilizer,
Lubricants, pigments, flame retardants, flame retardant aids and the like can be mentioned.

The modified polyolefin composition has a melt flow rate of 20 because it has excellent spinnability with a 4-methyl-1-pentene polymer and excellent drawability during fiber production.
~ 250 g / 10 min, preferably 20-2
It is 30 g / 10 minutes. In the present invention, the melt flow rate (MFR) is ASTM D1238.
The value is measured at a temperature of 260 ° C. and a load of 5 kg in accordance with the above.

The modified polyolefin composition also comprises
Generally, the specific gravity is about 0.89 to 0.91, and preferably about 0.89 to 0.90.

The modified polyolefin composition is produced by
It can be performed according to a known method and is not particularly limited. For example, a method in which the 4-methyl-1-pentene polymer and modified polypropylene, and various compounding agents that are compounded as necessary are supplied to an extruder and melt-kneaded, a ribbon blender, a Henschel mixer, and a tumbler blender. After blending using a blender, a blender is used to feed the mixture into an extruder for granulation, a high-concentration modified polypropylene and a 4-methyl-1-pentene polymer, and various blending agents blended as necessary. It can be performed according to the method of mixing in.

The fiber diameter of the fiber of the present invention is usually from 0.5 to
It is about 50 denier, and preferably about 2 to 40 denier in terms of the balance between the drawability and the draw strength during fiber production.

The fiber of the present invention has a length of about 1 to 100 mm, and preferably has a length of about 5 to 30 mm from the viewpoint of the balance between the dispersibility in the slurry and the fiber reinforcing effect.

The production of the fiber of the present invention can be carried out according to a conventional method and is not particularly limited. For example, the modified polyolefin composition can be melt-extruded, spun to form fibers, and then stretched.

Melt extrusion and spinning can be carried out by supplying the modified polyolefin composition to an extruder equipped with a die having an orifice having a required hole diameter, melt-kneading, and extruding the melt-kneaded product from the die. At this time, the temperature of the melt-kneading of the modified polyolefin composition is such that fibers having a smooth surface can be obtained by spinning, less yarn breakage occurs during stretching, and thermal decomposition of modified polypropylene or 4-methyl-1-pentene-based polymer. Is 250 to 350 ° C., and preferably 255 to 340 ° C.

The stretching can be carried out according to a known method and is not particularly limited. For example, the stretching of the modified polyolefin composition is performed by heating in a heating medium such as hot water, steam, or heating oil, or by contact with a heating body to obtain a temperature of 80 to
It can be stretched 2 to 10 times at 150 ° C.

The draw ratio is 2 times or more in that it can be blended with a cement board to obtain a fiber-reinforced cement board having excellent strength, and that the fiber of the present invention of good quality can be obtained without microcracks. And is preferably 3 to 8 times.

The fibers of the present invention can be used in the production of fiber reinforced cement boards using any cement,
There is no particular limitation. For example, it can be applied to a fiber-reinforced cement board using any cement such as Portland cement, blast furnace cement, and silica cement.

[0033]

EXAMPLES Next, the present invention will be specifically described with reference to examples and comparative examples, but the present invention is not limited to these examples as long as the gist thereof is not exceeded.

Example 1 <Production of Modified Polyolefin Composition> 4-Methyl-1-
Pentene polymer (manufactured by Mitsui Petrochemical Co., Ltd., trade name: DX350, MFR (260 ° C., under 5 kg load):
110 g / 10 minutes) 96 parts by weight, and maleic anhydride graft-modified polypropylene (maleic anhydride graft amount:
2.0 g / 100 g) and 4 parts by weight are supplied to a twin-screw extruder (PCM 45 mmφ manufactured by Ikegai Co., Ltd.) for 300 times.
Kneaded at ℃, modified polyolefin composition (maleic anhydride graft amount: 0.08g / 100g, MFR (260
C., under a load of 5 kg): 180 g / 10 minutes) was prepared.

<Production of Fiber for Cement Reinforcement> The modified polyolefin composition is fed to a single screw extruder (screw diameter: 30 mm) set at 290 to 310 ° C. and melt-kneaded, and hole diameter φ1.0 mm, number of holes. Extruded from 80 dies,
Melt spun for 30 minutes. At this time, the spinnability was evaluated according to the following criteria. ◯: No yarn breakage during melt spinning for 30 minutes. X: Thread breakage during melt spinning for 30 minutes. Then, stretched 6 times at a winding speed of 12 m / min in a stretching oil tank set at 140 ° C. A fiber for cement reinforcement having a fiber diameter of 20 denier was obtained. At this time, the stretchability was evaluated according to the following criteria. ◯: The number of yarn breakages during drawing was 0 × × The number of yarn breakages during drawing was 2 or more Next, the obtained cement reinforcing fiber was cut into a length of 20 mm and dispersed according to the following method. The sex was evaluated. The results are shown in Table 1.

<Dispersion Test of Cement Reinforcing Fiber> The following formulation: Portland cement: 92% by weight Inorganic papermaking aid: 6% by weight Cement reinforcing fiber: 2% by weight, solid content of 10% by weight, 90% by weight of water To prepare a slurry. This slurry was applied to a papermaking machine (Hascheck Mini Machine) for kneading and then left for 3 hours to take out a supernatant liquid formed on the upper portion of the slurry. The obtained supernatant is filtered through a filter, and the weight of the filter after filtration (measured weight) is measured as it is, and the ratio of floating fibers of the cement reinforcing fibers in the supernatant (fiber floating rate) is measured according to the following formula. Was evaluated and evaluated according to the following criteria. Fiber floating rate = [(measured weight-filter weight) / filter weight] x 100 (%)

<Evaluation Criteria for Dispersibility> A: Fiber floating rate of 10% or less Δ: Fiber floating rate of more than 10% and less than 30% ×: Fiber floating rate of 30% or more

(Examples 2 to 5) In each example, a modified polyolefin composition having the formulation shown in Table 1 was prepared, and using this, a fiber for cement reinforcement was produced in the same manner as in Example 1, and the spinnability and The stretchability was evaluated, and the dispersibility of the obtained cement reinforcing fiber was evaluated. The results are shown in Table 1.

(Comparative Examples 1 to 6) In each example, a composition having the formulation shown in Table 1 was prepared, and using this composition, fibers were produced in the same manner as in Example 1, and the spinnability and drawability were evaluated. At the same time, the dispersibility of the obtained fiber was evaluated. The results are shown in Table 1.
Shown in.

[0040]

[Table 1]

(Note) TPX: 4-methyl-1-pentene polymer (manufactured by Mitsui Petrochemical Co., Ltd., trade name: DX
350) Calcium charcoal: Calcium carbonate ○: Equal to or better than control product ×: Inferior to control product or no effect (* 1): Ritopon (reduced sintered product of BaSO ₄ + ZnS) (* 2): () The inside shows the obtained fiber floating rate (%). (* 3): Modified product: Maleic anhydride graft modified polypropylene Maleic anhydride graft amount: 2%

[0042]

The cement-reinforcing fiber of the present invention has a heat resistance characteristic of the 4-methyl-1-pentene polymer.
It has chemical resistance, steam resistance and light weight, and
It can be suitably used as a reinforcing fiber that can be well dispersed in a compounded slurry containing cement as a main component and containing water in the step of producing a fiber-reinforced cement plate.

Claims (2)

[Claims] 1. A 4-methyl-1-pentene-based polymer is graft-modified with at least one modifying monomer selected from unsaturated carboxylic acids and their derivatives, and the graft amount is 0.01 to 20% by weight. And a modified polypropylene having a melt flow rate of 20 to 250 g / 10.
A fiber for cement reinforcement, which is composed of a modified polyolefin composition. 2. A 4-methyl-1-pentene polymer and a graft modification with at least one modifying monomer selected from unsaturated carboxylic acids and their derivatives, and the graft amount is 0.01 to 20% by weight. And a modified polypropylene having a melt flow rate of 20 to 250 g / 10.
The modified polyolefin composition is
A method for producing a fiber for cement reinforcement, comprising a step of melt-extruding at a temperature of 0 ° C., spinning, and then stretching at a draw ratio of 2 times or more.