JPH11116354A - Production of molded product of resin-containing cement - Google Patents

Abstract

PROBLEM TO BE SOLVED: To readily contain a molded product that has uniform physical properties and stabilized mechanical strength in a shortened time by soaking its intermediate molded product comprising a thermoplastic resin and hydraulic cement in a mixture of an organic solvent with water. SOLUTION: In this invention, the thermoplastic resin is not particularly limited, any kinds of thermoplastic resins may be employed, for example, polyethylene or polypropylene. The cement is mainly a hydraulic cement as usual portland cement. The organic solvent is one or more kinds of organic solvents that can swell or dissolve thermoplastic resins, in the case that two or more kinds of organic solvent are used as a mixture, their mixing ratio is selected so that the mixture may be well compatible with water. Tetrahydrofuran and the like can be cited as an organic solvent that is compatible with water. Polyvinyl chloride and acetone can be cited as an example of' the combination of the resin with the solvent. The weight ratio of the resin to the cement is 100:(50-900).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a resin-containing cement molded product, and more particularly, to a material for construction and civil engineering which contains a thermoplastic resin and cement as main components and has physical properties intermediate between the two. The present invention relates to a method for forming a resin-containing cement molded article suitable for the use of the present invention.

[0002]

2. Description of the Related Art In recent years, as a building or civil engineering material of a cement-based molded body, for example, a plate, a block, or other forms, a thermoplastic resin is mixed with a cement as a main component and heated and molded. After that, a so-called resin-containing cement molded product obtained by curing and curing with water has been awarded. In addition to the original physical properties of the cement material, this molded product has improved bending strength and compressive strength, and has fewer defects such as deformation, shrinkage, and cracks. While it has advantages such as increased resistance, the cement curing process by hydration during the molding process is obtained by heating and molding a mixture of cement and thermoplastic resin at a temperature equal to or higher than the melting temperature of the thermoplastic resin. Since the method is based on the so-called post-hydration method, which comprises immersing the intermediate molded product in water, the degree of hydration varies between the parts of the molded product, for example, the surface layer and the inside, and uniform physical properties are obtained. There is a disadvantage that it cannot be done. As such a molding method, for example, JP-A-4-114978 can be mentioned.

[0003] Further, as a molding method in which the molding technique of a resin-containing cement molded article by the above-mentioned post-hydration method is improved, a hydrophilic substance is added to a thermoplastic resin and cement which are main components, or a water-absorbing fiber is added. There is known a method of obtaining a resin-containing cement molded article by adding a large amount of such a compound. In these methods, the step of curing the cement by hydration during the molding step involves immersing the intermediate molded product after heat molding the mixture in water, and the additive wets the thermoplastic resin with water. It is effective in giving hydration efficiently in the curing process, but depending on the desired shape, the hardening of the cement partially becomes excessive or insufficient,
Sufficient and uniform physical properties cannot always be obtained. As such a molding method, for example, JP-A-7-10626 is cited.

[0004] The inventors of the present invention have conducted intensive studies in view of the conventional problems as described above, and as a result, in the production of this type of resin-containing cement molded article, the curing of such an intermediate molded article by the post-hydration method has been considered. Is the thermoplastic resin in the intermediate molded product,
It is necessary not to hinder the contact with water, which is essential for cement curing, and if it is in a swelling or dissolving state, the hardening of the intermediate molded product can be accelerated, and the physical properties are homogeneous and satisfactory mechanical The inventors have found that a resin-containing cement molded article having high strength can be obtained, and have completed the present invention.

[0005]

That is, the present invention is based on the above-mentioned background and, in principle, utilizes a conventional method for producing a resin-containing cement molded body by a post-hydration method, A resin-containing cement that can cure an intermediate molded product consisting of a thermoplastic resin and cement in a short time, has intermediate physical properties between a thermoplastic resin and cement, and has uniform and stable mechanical strength. It is an object of the present invention to provide a method for producing a resin-containing cement molded article from which a molded article can be obtained.

[0006]

To achieve the above object, a first aspect of the present invention is to immerse an intermediate molded product comprising a thermoplastic resin and a hydraulic cement in a mixed solution of an organic solvent and water. Accordingly, the present invention provides a method for producing a resin-containing cement molded product, wherein the thermoplastic resin is cured while swelling.

In a second aspect of the present invention, an intermediate molded article comprising a thermoplastic resin and a hydraulic cement is immersed in an organic solvent to swell the thermoplastic resin, and then immersed in water. The present invention provides a method for producing a resin-containing cement molded body, which is characterized by being cured by the above method.

That is, in the present invention, an intermediate molded product obtained by heating and kneading a mixture of a thermoplastic resin and hydraulic cement is immersed in a mixed solution of an organic solvent and water to hydrate the hydraulic cement. (1st invention) or immersion in an organic solvent and then further immersion in water to hydrate the hydraulic cement (2nd invention). The thermoplastic resin is immersed in the intermediate molded product by the organic solvent. Swelling facilitates water penetration, promotes the hydration reaction of the hydraulic cement with water, and uniformly cures the entire intermediate molded product. In this case, there is no problem if the first and second inventions are compromised so that the hydraulic cement is hydrated by being immersed in a mixed solution of an organic solvent and water and then further immersed in water.

Next, the thermoplastic resin used in the present invention will be described. The thermoplastic resin is not particularly limited, and all kinds of thermoplastic resins can be applied. Further, the thermoplastic resin is not limited to the same kind, and may be used by mixing with a different kind. Furthermore, from the so-called synthetic resin waste material, which is a mixture of thermoplastic resin and thermosetting resin, thermosetting resin, metal, soil, sand, other dust and foreign matter are roughly separated and removed, and the remaining thermoplastic resin-based synthesis is performed. It can be applied to resin waste. Hereinafter, when the main thermoplastic resins are specifically listed, polyethylene, polypropylene, polyvinyl chloride, ethylene-vinyl acetate copolymer, acrylonitrile-butadiene-styrene copolymer, acrylonitrile-acrylic rubber-styrene copolymer, acrylonitrile -EPDM-styrene copolymer, acrylonitrile-chlorinated polyethylene-styrene copolymer, methyl methacrylate-butadiene-styrene copolymer, ethylene-vinyl chloride copolymer, polyvinylidene chloride, chlorinated polyolefin-butadiene copolymer, Polyacetal, polyamide, polyethylene terephthalate, polycarbonate, polystyrene, polymethyl methacrylate, urethane-based thermoplastic elastomer,
Polybutylene terephthalate, polyphenylene ether, polyarylate, liquid crystal polymer, polytetrafluoroethylene, polyether ketone, polyether ether ketone, polyether sulfone, styrene-based thermoplastic elastomer, olefin-based thermoplastic elastomer,
Examples include polyester-based elastomers, polyamide-based elastomers, polybutadiene-based elastomers, vinyl chloride-based elastomers, and asphalt.

Further, the cement used in the present invention is mainly hydraulic cement, for example, Portland cement hydraulic cement such as ordinary Portland cement, blast furnace cement, fly ash cement, white cement, etc. It is a hydraulic cement such as an early-strength cement, an alumina cement, an oxychloride cement, an acid-resistant cement, and a gypsum. It is also composed of two or more components and reacts with water to become hydraulic, for example, activated silica and water. Calcium oxide, activated alumina and calcium hydroxide are also applicable, and furthermore, two or more of the above cements can be mixed and applied.

Further, in the present invention, the organic solvent used for curing the intermediate molded product is one or two types capable of swelling or dissolving the thermoplastic resin selected from the above-mentioned thermoplastic resins. At least one of them is an organic solvent that is compatible with water, and at least one of them is an organic solvent that is compatible with water. I do. For example, organic solvents that swell the polyvinyl chloride resin include acetone, dioctyl phthalate (DOP), and dibutyl phthalate (DBP). Organic solvents that dissolve the polyvinyl chloride resin include tetrahydrofuran (THF), cyclohexanone, and the like. Examples include nitrobenzene, dioxane, dichloromethane, carbon tetrachloride and the like.
Examples of the organic solvent having compatibility with water include tetrahydrofuran (THF), acetone, and methyl ethyl ketone (MEK). In addition, here, the organic solvent which is compatible with water, in addition to the one which is itself compatible with water,
Includes those that are incompatible with water by themselves, but compatible with other organic solvents that are compatible with water. For example, it is a mixed solution composed of 70% by volume of acetone that is compatible with water, 10% by volume of cyclohexanone that is incompatible with water alone, and 20% by volume of water.

Here, the mixing ratio of the organic solvent to water is such that the ratio of the organic solvent to water is within a range in which the thermoplastic resin swells. That is, the mixing ratio is such that the mixed solution of the organic solvent and water is sufficient to swell the thermoplastic resin and does not dissolve the thermoplastic resin. In this case, the upper limit of the proportion of the organic solvent is not necessarily strict, and it is assumed that the proportion is such that a slight portion of the thermoplastic resin is dissolved.

Next, as a specific example of the combination of the thermoplastic resin and the organic solvent, tetrahydrofuran (THF) or acetone is desirable for polyvinyl chloride resin, and cyclohexanone, nitrobenzene,
It is preferable to use one added with at least one selected from methyl ethyl ketone (MEK), dioxane and the like, or a so-called plasticizer such as dioctyl phthalate and dibutyl phthalate.

In the present invention, the mixing ratio of the thermoplastic resin and the cement differs depending on the type of the thermoplastic resin, but the range is from 50 to 900 parts by weight of the hydraulic cement to 100 parts by weight of the thermoplastic resin. And

As a mixture for obtaining an intermediate molded product according to the present invention, in addition to the thermoplastic resin and the cement,
Glass fibers or metal fibers for improving the brittleness of the cement may be added, and foaming agents, pigments, light stabilizers, heat stabilizers, etc. may be added depending on the application. Then, in addition to heating and kneading the mixture to form a plate-shaped intermediate molded product,
Further, an intermediate molded product obtained by laminating and integrating this with a glass net or a metal net by a heating laminating means may be used.

Next, the means for mixing and forming an intermediate molded product in the present invention will be described. First, as a means for mixing the thermoplastic resin and the hydraulic cement, a commonly used mortar mixer or blender is used. Applied. In this case, in order to improve the degree of mixing between the thermoplastic resin and the additive other than the hydraulic cement, the thermoplastic resin may be heated to a temperature lower than the melting temperature, preferably lower than the heat deformation temperature. Then, as a means for heat molding the mixture to obtain an intermediate molded product, the thermal properties at the time of heat molding of the mixture, which are expressed by the type of the thermoplastic resin used, the mixing ratio, the type and amount of the additive, etc. Any known means can be selected as a means for heat-molding a thermoplastic resin as long as the method conforms to the above, and molding methods such as injection molding, extrusion molding, press molding, and compression molding can be applied. For example, in press molding, first, the mixture is heated and kneaded at a temperature equal to or higher than the melting temperature of the thermoplastic resin by a mixing roll used for kneading a normal thermoplastic resin as a device for heating and kneading, and this is formed into a sheet. After rolling, the sheet is further subjected to compression molding while heating using a press in a single layer or in a laminated state to obtain a plate-shaped resin-containing cement molded body. It is essential that the heating temperature in the thermoforming be a temperature equal to or higher than the melting temperature of the thermoplastic resin to be used. Further, the set temperature is changed according to the type of each component of the mixture, the mixing ratio, the thermoforming means and the like. be able to. For example, when the thermoplastic resin is a vinyl chloride resin, the heat molding temperature by a press is set to a temperature in the range of 120 to 180 ° C.

The intermediate molded product obtained above is immersed in a mixed solution of an organic solvent and water to cure the thermoplastic resin while swelling, or is immersed in an organic solvent and then immersed in water. By doing so, the hydraulic cement is hydrated and the intermediate molded product is hardened as a whole, but at this time, the thermoplastic resin in the molded product swells due to the organic solvent penetrating from the surface of the intermediate molded product to the inside. As a result, water easily or shortly penetrates into the interior of the intermediate molded product together with or after the organic solvent, and comes into contact with the hydraulic cement in the molded product, and the water is rapidly removed. It will sum up.

In the step of hydrating the intermediate molded product, the organic solvent or a mixed solution of the organic solvent and water is heated to a relatively low temperature (for example, 20 to 60 ° C.) at which the organic solvent does not evaporate. Further, by pressurizing to a relatively low pressure of about 5 to 6 kg / cm ² , the hydration of the hydraulic cement can be made more effective. Further, if the organic solvent remains in the resin-containing cement hydrated by the method of the present invention, it causes a decrease in mechanical properties. Therefore, it is desirable to remove these surplus organic solvents. This removing method can be performed by placing the molded body in a heated state or a reduced pressure state.

[0019]

EXAMPLES Examples of the present invention will be described below along with comparative examples. In addition, the evaluation of the resin-containing cement molded body obtained by each of the examples and the comparative examples was such that when the cement was hydrated, a whitening phenomenon occurred. Calcium (C
Based on the fact that the presence of a (OH) ₂ ) was observed, the surface and inside of the molded article were observed, and appropriate hydration was performed when the whitening state was almost the same in any part. The evaluation was based on the length of time required for the state.

Example 1 Vinyl chloride resin (degree of polymerization: 700, particle size: 100 μm) 10
0 parts by weight, 200 parts by weight of ordinary Portland cement,
3 parts by weight of the tin-based stabilizer was charged into a mixer, and the mixer jacket was heated to 40 ° C. and mixed with stirring. This mixture was heated and kneaded at 170 ° C. for 10 minutes using a mixing roll, rolled to form a sheet having a thickness of 1 mm, and five sheets were laminated and heated and pressurized at a temperature of 170 ° C. by a press to integrally form a laminate. To obtain an intermediate molded product having a thickness of 5 mm. The obtained plate-shaped intermediate molded product was immersed in an aqueous solution containing 30% of tetrahydrofuran (THF) at a temperature of 45 ° C. for 24 hours. Then, at a temperature of 75 ° C. for 12 hours to remove excess tetrahydrofuran (THF).
Dried for hours. The molded article thus obtained was a resin-containing cement molded article in which hydration had progressed uniformly from the surface to the center. The flexural modulus of this molded body is 6000
[N / mm ² ].

Example 2 An intermediate molded product having a thickness of 5 mm was obtained in the same manner as in Example 1, and this was immersed in an acetone solution at room temperature for 12 hours, and then further immersed in warm water at 45 ° C. for 12 hours. . The obtained molded article was a resin-containing cement molded article in which hydration progressed uniformly from the surface to the center. The flexural modulus of this molded product was 6,500 [N / mm ² ].

Example 3 An intermediate molded product having a thickness of 5 mm was obtained in the same manner as in Example 1 and immersed in an aqueous solution containing 30% of tetrahydrofuran (THF) at a temperature of 45 ° C. for 6 hours.
For 12 hours. The obtained molded article was a resin-containing cement molded article in which hydration progressed uniformly from the surface to the center. The flexural modulus of this molded product is 650.
0 [N / mm ² ].

Comparative Example 1 An intermediate molded product having a thickness of 5 mm was obtained in the same manner as in Example 1, and this was immersed in warm water at 80 ° C. for 72 hours. The obtained molded body was hydrated from the surface layer to about 0.5 mm, and the inside was less than completely hydrated. The flexural modulus of this molded product was 3000 [N / mm ² ].

As is evident from the above results, the resin-containing cement molded article according to the present invention was one in which both the surface layer and the inside were uniformly hydrated and the flexural modulus was sufficiently maintained.

[0025]

As described above, according to the present invention, an intermediate molded product obtained by heating and kneading a mixture of a thermoplastic resin and a hydraulic cement is immersed in a mixed solution of an organic solvent and water to obtain a hydraulically By hydrating the cement or immersing it in an organic solvent and then further immersing it in water to hydrate the hydraulic cement and swelling the thermoplastic resin with the organic solvent penetrating into the intermediate molded product, Since the hydration reaction of hydraulic cement with water is promoted by facilitating permeation, it is possible to easily and quickly produce a resin-containing cement molded body having uniform physical properties and stable mechanical strength. There is an effect that can be.

Claims (2)

[Claims] 1. A resin characterized in that an intermediate molded product comprising a thermoplastic resin and a hydraulic cement is immersed in a mixed solution of an organic solvent and water, whereby the thermoplastic resin is cured while being swollen. A method for producing a cement-containing body. 2. An intermediate molded article comprising a thermoplastic resin and a hydraulic cement is immersed in an organic solvent to swell the thermoplastic resin, and then cured by immersion in water. A method for producing a resin-containing cement molding.