JP2585668B2 - Low pressure extrusion method of hollow plate containing reinforcing fiber - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a low-pressure extrusion method of a cement-based hollow extruded plate that does not contain asbestos fibers and has high safety. The hollow extruded plate obtained by the method of the present invention is excellent in fire resistance, lightness, safety, and weather resistance, and thus is suitable for a board for building interior and exterior.

<Prior art> Conventionally, extrusion hollow molding of cement has been performed by extruding a mixture of cement, water, a water-soluble polymer or an aqueous dispersion of a polymer, and reinforcing fibers into a hollow shape at a high pressure of 15 to 30 kg / cm ² . After that, it was cured by a method such as natural curing, steam curing, or autoclave curing.

<Problems to be Solved by the Invention> The problem with the hollow extrusion molding of the cement-based inorganic compound of the prior art is that, first, the mixture of the raw materials is formed into a hard clay in order to prevent the shape of the hollow extrusion molding from being deformed. It is necessary to extrude at a high pressure of 15 to 30 kg / cm ² to be kneaded and supplied to an extruder, and secondly, the raw material composition is aqueous,
The point is that asbestos fibers having a high affinity for inorganic compounds such as water and cement have been used as main reinforcing fibers. That is, the conventional method by mixing a water-soluble polymer compound and reinforcing fibers such as cellulose to the cement, to blow molding a material obtained by a hard clay-like in high pressure 15~30kg / cm ^2, is significantly damaged reinforcing fibers A sufficient reinforcing effect was not obtained. In addition, when mixed with lightweight aggregates such as shirasu balloon, perlite, expanded styrene, etc., it is destroyed by high pressure,
The expected lightness was not obtained. In addition, the extruder itself needs to be designed to withstand high pressure, consumes a large amount of electricity,
Screw wear was also significant. In addition, since the raw material is water-based, it has poor affinity with reinforcing fibers other than asbestos, especially synthetic resin reinforcing fibers such as polypropylene, polyester, vinylon, nylon, acrylic, aramid, polyethylene, and vinyl chloride fibers. Was inferior. On the other hand, asbestos fibers have carcinogenic properties, and asbestos is scattered at the time of cutting during production or construction, and there is a great risk of impairing human health.

An object of the present invention is to provide a method for low-pressure extrusion of a hollow plate containing a reinforcing fiber in which these problems have been solved.

<Means for Solving the Problem> The present invention relates to a water-insoluble vinyl monomer containing a polymerization initiator and a demulsifier, cement and water having an aspect ratio of 100.
~ 2000, 3 kg of cement-containing W / O emulsion in which reinforcing fibers obtained from synthetic fibers having a length of 2 to 20 mm are dispersed
/ cm ² or less, preferably 0.1 to ² kg / cm ² Extrusion into a hollow at a low pressure, natural curing, steam curing or autoclave curing, polymerization reaction of vinyl monomer and hydration reaction of cement proceed. The present invention provides a method for obtaining a hollow extruded plate that is lightweight, excellent in fire resistance and excellent in safety after drying after curing.

That is, comparing the conventional method and the method of the present invention,
The composition to be extruded differs significantly in extrusion pressure. In the conventional method, water is used as a continuous phase, in which cement and reinforcing fibers are dispersed, but according to the method of the present invention, a vinyl monomer is used as a continuous phase, and water and cement are contained therein. Contains cement dispersed
The extrusion molding raw material in a state where the reinforcing fibers are dispersed in the W / O emulsion is extruded. The continuous phase of the inverse emulsion of this raw material composition, that is, since the matrix is an oily vinyl monomer, compared with the conventional raw material composition comprising a cement-water-soluble polymer compound, the synthetic resin-based reinforcing fibers and Has a remarkably high affinity, so that they exhibit excellent effects in dispersibility, fluidity and reinforcing effect. Further, the fact that the cement-containing W / O emulsion of the present invention has high thixotropy is advantageous for producing a hollow extruded product. The cement-containing W / O emulsion easily flows when a large force is applied thereto, but has a property that the shape does not easily collapse when left standing. That is, since the fluidity is high at the time of kneading and extrusion molding, extrusion molding can be performed at a low pressure of 3 kg / cm ² or less, but a hollow molded article has a characteristic that the shape is not easily deformed. This is presumed to be due to the emulsion structure of the cement-containing W / O emulsion. Due to the characteristics described above, the cement-containing W / O emulsion of the present invention can produce a hollow extruded plate at a low pressure of 3 kg / cm ² or less, even though reinforcing fibers are mixed therein. It was. Conventionally,
In terms of reinforcing effect, dispersibility, and moldability (flowability), the use of synthetic fibers, which were difficult to use in hollow molding, has become possible because of the formation of a cement-containing W / O emulsion matrix. Due to the high lubricity of the vinyl monomer and its affinity with synthetic fibers, the synthetic resin reinforcing fibers are easily and uniformly dispersed in the cement-containing W / O emulsion, and the reinforcing effect of the polymerized cured product is more than asbestos The effect of is shown.

In the present invention, in order to produce a cement-containing W / O emulsion, water is used in an amount of 40 to 500 parts by weight, preferably 50 to 200 parts by weight, based on 100 parts by weight of cement, and a water-insoluble vinyl monomer and a deemulsifier, 1 to 20% by weight, preferably 2 to 10% by weight, of a mixture of cement and water is added to a vinyl monomer solution comprising the agent and mixed with a commercially available mixer. The formation time depends on the type of mixer, but contains a soft clay-like cement that becomes sticky by stirring for 0.5 to 5 minutes.
A W / O emulsion is formed. This cement containing W / O
Type emulsions are oily and do not dissolve in water. As the reinforcing fiber, a synthetic fiber having an aspect ratio of 100 to 2000 and a length of 2 to 20 mm is used. The mixing ratio is 0.3 to 5% by weight, preferably 0.5 to 3% by weight of the cement-containing W / O emulsion.
% By weight. The mixing method may be added together with other raw materials before forming the cement-containing W / O emulsion, or may be mixed after forming the W / O emulsion. In any of the mixing methods, the reinforcing fibers are easily and uniformly dispersed.

As the cement used in the present invention, Portland cement, blast furnace cement, fly ash cement, silica cement, alumina cement, or silicate compound,
And mixtures of calcium compounds. These may be used alone or as a mixture.

Examples of the reinforcing fibers include synthetic fibers such as polypropylene, polyester, vinylon, nylon, acrylic, and aramid fibers having an aspect ratio of 100 to 2000 and a length of 2 to 20 mm. If the length is smaller than 2 mm and the aspect ratio is smaller than 100, the reinforcing effect is poor. If the length is larger than 20 mm and the aspect ratio is larger than 20, the formability and dispersibility will be poor. Therefore, these reinforcing fibers have an aspect ratio of 100 to 2000,
Preferably the length is between 2 and 20 mm.

Suitable vinyl monomers are liquid at room temperature and hardly soluble in water. For example, styrene, α-methylstyrene, acrylic ester, methacrylic ester, acrylonitrile, divinylbenzene, acrylic acid or methacrylic ester of alkylene glycol, acrylic acid or methacrylic ester of polyhydric alcohol and the like can be mentioned. These may be used alone or as a mixture of two or more. Among the above vinyl monomers, it is particularly preferable to use a vinyl monomer mixture containing styrene as a main component. In addition, for the purpose of increasing the strength and polymerization characteristics of the molded product, dimethacrylate of polyhydric alcohol, or trimethacrylate compound, for example, ethylene glycol dimethacrylate, trimethylol, it is generally used in combination with a divinyl compound such as propane trimethacrylate or a trivinyl compound. preferable.

A polymerization catalyst is mixed with the vinyl monomer in order to promote a curing reaction after molding, and a general radical forming agent or a redox catalyst is used as the polymerization catalyst according to a normal formulation.

The de-emulsifier used to form a cement-containing W / O emulsion is used by dissolving a nonionic surfactant having an HLB value of 3 to 6 in a proportion of 3 to 50% by weight with respect to a vinyl monomer. Even so, a cement-containing W / O emulsion is formed. In the present invention, the nonionic surfactant having an HLB value of 3 to 6 includes, for example, sorbitan sesquiolate, glycerol monostearate, sorbitan monooleate, diethylene glycol monostearate,
Sorbitan monostearate, diglycerol monooleate, maleic anhydride adduct of alkylene glycol and the like can be mentioned. These may be used alone or as a mixture of two or more. When used alone, sorbitan monooleate and diglycerol monooleate are preferred. In addition, if necessary, perlite, vermiculite, shirasu balloon, glass balloon, synthetic resin foam, or the like may be mixed as a lightweight aggregate. Sand, inorganic powder, and organic powder may be added as an extender.

The cement-containing W / O emulsion containing the reinforcing fibers formed by the method described above is extruded by an extruder equipped with a die for forming a hollow plate. The hollow plate referred to in the present invention is a plate-like material having a large number of columnar hollow holes parallel to the extrusion direction. Extrusion pressure at this time varies depending on the composition, significantly lower compared to 15~30kg / cm ² conventional hollow extrusion method at about 0.1~2kg / cm ^2. Therefore, the reinforcing fibers are not damaged and the lightweight aggregate is not damaged, and the load on the motor is low and the power consumption is small. Also, there is almost no wear on the screw even during long-time operation. The extruded hollow molded plate undergoes polymerization of a vinyl monomer and hydration of cement by natural curing, steam curing, and autoclave curing, and after being cured, is dried to remove moisture. The obtained hollow molded plate is lightweight, does not collapse, and maintains the shape at the time of molding. Depending on the composition, it is also possible to produce a very lightweight hollow molded plate having a specific gravity of 0.5 or less. This is because the polymerization reaction of the vinyl monomer and the hydration reaction of the cement proceed while maintaining the inverse emulsion structure, which is the characteristic of the cement-containing W / O emulsion. And has a fine cell structure composed of a composite of the above and further reinforced by reinforcing fibers. That is, it is a great feature that the fiber structure is a fiber-reinforced porous structure in which the crystal structure formed by the hydration reaction of cement and the cell structure are combined.

<Example> Hereinafter, the present invention will be described in more detail with reference to examples.

Example 1 In a continuous kneader, Portland cement was 307.8 k / h.
g, water 275.4kg / h, vinyl monomer solution 16.0k / h
g, an acrylic fiber having an aspect ratio of 333 and a length of 6 mm were continuously supplied at 5 kg / h to obtain a cement-containing W / O emulsion in which reinforcing fibers were well dispersed. However, the vinyl monomer solution was a mixture of 69 parts by weight of styrene monomer, 25 parts by weight of sorbitan monooleate, 5 parts by weight of trimethylolpropane trimethacrylate, and 1 part by weight of benzoyl peroxide. The obtained cement-containing W / O emulsion was soft clay-like and did not dissolve in water. This cement-containing W / O emulsion composition was continuously fed to an extruder equipped with a die for blow molding, and 0.3 k
A hollow plate having a thickness of 18 mm, a width of 455 mm, and a hollow ratio of 25% was continuously extruded at an extrusion pressure of g / cm ² . The obtained extruded plate was steam cured at 50 ° C. for 17 hours, 90 ° C. for 24 hours, and then dried,
A hollow molded plate having a specific gravity of 0.75 was obtained. This hollow molded plate maintained the same shape as that at the time of the extrusion molding, and no deformation or shape collapse was observed. The bending fracture load of the obtained hollow plate based on JIS A1408 reached 150 kg with a thickness of 18 mm.

Example 2 453.6 kg / h of blast furnace cement, 226.8 kg / h of water, 16.0 kg / h of a vinyl monomer solution, 7.0 kg / h of vinylon fiber having an aspect ratio of 1000 and an aspect ratio of 12 mm were continuously supplied to a continuous kneader. Well-dispersed cement-containing W /
An O-type emulsion was obtained. However, the vinyl monomer solution was a mixture of 74 parts by weight of styrene monomer, 5 parts by weight of ethylene glycol dimethacrylate, 20 parts by weight of diglycerol monooleate, and 1 part by weight of t-butyl peroxybenzoate. The obtained cement-containing W / O emulsion was soft clay and did not dissolve in water. The cement-containing W / O emulsion composition is continuously supplied to an extruder equipped with a die for hollow molding, and a hollow plate having a thickness of 18 mm, a width of 455 mm, and a hollow ratio of 30% is applied at an extrusion pressure of 0.5 kg / cm ^2. Was continuously extruded. The obtained extruded plate is heated at 50 ° C for 17 hours, 90 ° C
For 24 hours, cured and dried to obtain a hollow molded plate having a specific gravity of 1.1. This hollow molded plate maintained the same shape as that at the time of the extrusion molding, and no deformation or shape collapse was observed. The resulting hollow molded plate had a flexural breaking load of 180 kg based on JISA1408.

Example 3 Portland cement in continuous kneader at 162.0k / h
g, 324.0 kg of water, 16.0 kg of vinyl monomer solution per hour, aspect ratio of 500, aramid fiber with length of 6 mm, 10.0 per hour
kg of cement-containing W / O-type emulsion in which reinforcing fibers were well dispersed was obtained. However, the vinyl monomer solution was a mixture of 64 parts by weight of styrene monomer, 30 parts by weight of sorbitan monooleate, 5 parts by weight of trimethylolpropane trimethacrylate, and 1 part by weight of t-butylperoxyisopropyl carbonate. The obtained cement-containing W / O emulsion was soft clay-like and did not dissolve in water. The cement-containing W / O emulsion composition was continuously fed to an extruder provided with a die for hollow plate molding, an extrusion pressure of 0.2 kg / cm ^2, thickness 18 mm, width 455 mm,
A hollow plate having a hollow ratio of 20% was continuously extruded. The obtained extruded plate was steam-cured at 60 ° C. for 8 hours and then at 135 ° C. for 18 hours.
It was cured by steam curing in an autoclave and then dried to obtain a hollow molded plate having a specific gravity of 0.52. This hollow molded plate maintained the same shape as that at the time of the extrusion molding, and no deformation or shape collapse was observed. The bending fracture load of the obtained hollow plate based on JISA1408 was 18 mm thick and 100 kg.

Example 4 54 parts by weight of styrene monomer, 10 parts by weight of acrylonitrile, 30 parts by weight of maleic anhydride adduct of polyalkylene glycol having an average molecular weight of 2,000, 5 parts by weight of erylenglycol dimethacrylate, 1 part by weight of benzoyl peroxide, Portland cement 400 Parts by weight, 800 parts by weight of water, 20 parts by weight of Shirasu balloon, and 13 parts by weight of polypropylene fiber were mixed and stirred by a double-arm kneader to obtain a cement-containing W / O emulsion in which reinforcing fibers were well dispersed. This cement-containing W / O emulsion did not dissolve in water. This cement-containing W / O emulsion composition is extruded at an extrusion pressure of 0.7 kg / cm ² with an extruder equipped with a die for hollow molding, and is a hollow plate having a thickness of 18 mm, a width of 455 mm, and a hollow ratio of 20%. Was continuously extruded. The obtained extruded plate was left standing at room temperature for 28 days, cured, and then dried to obtain a hollow plate having a specific gravity of 0.45. This hollow molded plate maintained the same shape as that at the time of extrusion molding, and no deformation or deformation was observed, and the shirasu balloon was not broken. The bending fracture load based on JISA1408 of the obtained hollow plate was 18 kg and 86 kg.

<Comparative Example 1> 60 parts by weight of Portland cement, 12 parts by weight of silica sand, 12 parts by weight of asbestos, 9 parts by weight of Shirasu balloon, and 1 part by weight of methylcellulose were mixed with powder, and asbestos was dispersed well.
60 parts by weight of water was added to make a clay, and extruded with an extruder equipped with a die for forming a hollow plate at an extrusion pressure of 3 kg / cm ² to obtain a hollow having a thickness of 18 mm, a width of 455 mm, and a hollow ratio of 25%. The plate was continuously extruded as in Example 1. When the obtained hollow molded plate was cured and dried in the same manner as in Example 1, the shape retention was poor.
It gradually deformed and the hollow part collapsed significantly. It could not be put to practical use due to the entire deformation.

<Effects of the Invention> As described above, according to the method of the present invention, the length of the aspect ratio 100 to 2000 is 2 to 20 mm, as is clear from the examples and comparative examples.
The hollow fiber can be hollow-extruded at a low pressure of 3 kg / cm ² or less from a cement-containing W / O emulsion in which the synthetic fibers are uniformly dispersed. Further, the hollow molded plate obtained by curing and drying this has a low specific gravity and does not collapse. In addition, even if the mixing ratio of the reinforcing fiber is low, it shows high strength. This is because the cement-containing W / O emulsion of the present invention has a high affinity for synthetic fibers, and is not damaged at all during extrusion. That is, a safe, high-strength, lightweight cement-based hollow extruded plate free of asbestos can be easily produced by the method of the present invention.

Claims (1)

(57) [Claims] 1. A water-insoluble vinyl monomer containing a polymerization initiator and an inverse emulsifier, cement and water having an aspect ratio of 100
~ 2000, a cement-containing W / O emulsion in which reinforcing fibers obtained from synthetic fibers having a length of 2 to 20 mm are dispersed,
A method for extruding a hollow plate, comprising extruding a hollow plate at a low pressure.