JP3123814B2 - Composition for artificial stone - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composition for producing artificial stone having the texture of natural stone. This composition for artificial stone has the property that it can be a cured product having the texture of natural stone simply by kneading with water without using an organic solvent which is unfavorable in the working environment.

[0002]

2. Description of the Related Art With the diversification of requirements for building materials, not only various natural stone materials but also artificial stone materials have been widely used in recent years. Among them, artificial stones using an organic resin have been developed in various compositions due to the ease of diversification of their shapes. These artificial stone materials are mainly made by kneading stone powder obtained by pulverizing natural stone with an organic resin. In the production of such artificial stone materials, it is common to use some organic solvent in order to improve the handling and other properties at the time of molding. However, many of these organic solvents are unfavorable for the human body, and those which do not use organic solvents in the working environment have been desired. There is a water-soluble resin as a resin that can provide practically trouble-free handling characteristics without using an organic solvent, but this is simply mixed with stone powder obtained by pulverizing natural stone and molded and solidified. It could not be used practically as artificial stone.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to cure a mixture of stone powder and a resin using an organic solvent by kneading and curing with water using a water-soluble organic resin. Another object of the present invention is to provide a material for artificial stone capable of obtaining strength equivalent to that of natural stone and obtaining the texture of natural stone.

[0004]

The above-mentioned object is achieved by a composition for artificial stone characterized by comprising metakaolin, citric acid and at least one of a water-soluble melamine resin and a water-soluble phenol resin.

The metakaolin used in the present invention includes:
Natural kaolinite over 500 ℃, especially 600 ℃
Although what is obtained by heating at 800 ° C. to form a dehydrated acid group is preferable from the viewpoint of production cost, when improving the whiteness of the cured product, artificially synthesized kaolin is used. May be. In the composition for artificial stone of the present invention, it is essential to use metakaolin,
In the case where mere kaolinite which does not pass through the step of dehydration and acidification by heating is used, the curing time at ordinary temperature is longer than that in the case where metakaolin is used. Absent.

In the present invention, at least one selected from a water-soluble melamine resin and a water-soluble phenol resin is used as the water-soluble resin. The water-soluble melamine resin is a resin obtained by condensing melamine with formaldehyde or a lower aliphatic aldehyde, and the water-soluble phenol resin is a resin obtained by condensing fehl with formaldehyde or a lower aliphatic aldehyde.

The mixing ratio of metakaolin to the water-soluble resin is 1 to 40 parts by weight, preferably 10 to 20 parts by weight of the solid content of the water-soluble resin with respect to 100 parts by weight of the metakaolin. Water-soluble solid content ratio is 1
If the amount is less than parts by weight, the amount of kneading water for obtaining practical fluidity must be increased, and as a result, the curing time at room temperature becomes longer and the flexural strength of the cured body itself becomes lower, which is not preferable. If this amount exceeds 40 parts by weight,
The distance between the metakaolin particles becomes unnecessarily large, and the space therebetween is occupied by the resin. As a result, the compressive strength decreases, which is not preferable.

[0008] In the composition for artificial stone of the present invention, citric acid is used in combination with a water-soluble resin as a curing agent. By using the citric acid together, a cured product having high compressive strength can be obtained from the artificial stone material composition. By using citric acid, a cured product having higher strength can be obtained as compared with the case where many other curing agents known as curing agents for water-soluble melamine resin and water-soluble phenol resin are used. The mixing ratio of citric acid is 30 to 100 parts by weight, preferably 45 to 55 parts by weight, based on 100 parts by weight of the solid content of the water-soluble resin. If the amount of the citric acid is more than 100 parts by weight or less than 30 parts by weight, the compressive strength becomes weak, which is not preferable because of lack of practicality.

The artificial stone material composition of the present invention is kneaded by adding an appropriate amount of water, poured into an appropriate mold, and cured to give an artificial stone material having a natural stone texture. The amount of water kneaded with the artificial stone composition is preferably as small as possible within the allowable range of handling such as pouring into a mold in consideration of the strength of the cured product. 30-50 for 100 parts by weight of product
Parts by weight, preferably 40 parts by weight.

[0010] The composition for artificial stone of the present invention can be prepared by, for example, mixing each component as a powder and kneading by adding water, or
A part of the composition may be dissolved in water in advance, and the resulting composition may be kneaded with the rest before use. The kneaded material is poured into an appropriate mold and cured at room temperature or, if necessary, at about 50 to 60 ° C. to obtain the desired artificial stone.

In the artificial stone composition of the present invention, if desired, a natural stone such as granite can be mixed as an aggregate. However, since the artificial stone obtained from the composition of the present invention is opaque, the aesthetics of the aggregate are not sufficiently activated in a product that has been manufactured by being poured into a mold. Further, calcined feldspar powder can be mixed with the artificial stone material composition of the present invention, and by changing the amount thereof added, the composition can be colored in a cream color without lowering the strength. Then, a marble-like artificial stone material can be obtained by alternately stacking materials having different concentrations.

[0012]

In the artificial stone material composition of the present invention, the hydroxyl group of the water-soluble melamine resin or the water-soluble phenol resin and the carboxyl group of citric acid undergo an esterification reaction, and citric acid has an enhanced surface activity. Due to the chelation reaction with Al ^{3+ in} metakaolin, the stone obtained from the composition of the present invention exhibits greater strength as compared with a mixture obtained by simple van der Waals bonding.

[0013]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist of the present invention. Example 1 An artificial stone sample was prepared as follows. That is, natural kaolinite for ceramics was calcined in an electric furnace at 800 ° C. for 3 hours to obtain metakaolin for preparation. To 100 parts by weight of this metakaolin, a commercially available water-soluble melamine resin ("Madrit 909" manufactured by Hoechst Japan K.K.), citric anhydride and water were blended at the ratio shown in Table 1, and 20 parts by weight were mixed.
Kneaded at ℃. The mixing amount of the kneading water was 40% by weight based on the solid composition. Place the kneaded material in a mold, 60 ° C
Cultivated in a drying oven set for 1 day, 6 mm in diameter,
A cylindrical specimen having a height of 12 mm was obtained. The compressive strength of this specimen was measured. Head speed of compression tester is 2
Inches / minute. Table 1 shows the measurement results.

[0014]

[Table 1]

Comparative Example 1 For comparison, a specimen was prepared in exactly the same manner as in Example 1 except that natural kaolinite was used instead of metakaolin, and the compressive strength was measured. Table 2 shows the results.

[0016]

[Table 2]

Comparative Example 2 An organic curing agent containing a sulfonic acid group, which is widely used and commercially used as a curing agent for methylolmelamine, was used in the same manner as in Example 1 except that citric acid was used instead. Specimens were prepared and the compressive strength was measured. Table 3 shows the results.

[0018]

[Table 3]

As is clear from the above examples, the composition for artificial stones according to the present invention can be put to practical use as artificial stones by simply kneading with water without using an organic solvent which is not preferable in working environment. Strength is obtained. In this case, it is necessary to use metakaolin obtained by dehydrating kaolin and, as shown in Comparative Example 1, when mere dried kaolin is used, a cured product having high strength cannot be expected.

This is presumed to be due to the fact that the crystal structure of kaolin is destroyed during the process of dehydration of kaolin, and as a result, some kind of reaction which leads to an increase in the strength of the cured product occurs. In addition, it is considered that citric acid greatly contributes to the occurrence of this reaction. In our experiments, we used many other water-soluble melamine resins and water-soluble phenolic resin curing agents (including the sulfonic acid group-containing curing agent described in Comparative Example 2). Did not give a cured product having such a high strength as can be obtained when citric acid was used.

The texture of the cured product of Example 1 was glossy without polishing, due to the interaction between metakaolin and melamine resin, and was similar to that of natural stone polished. Although similar results were obtained in experiments using a water-soluble phenol resin, the cured product had a yellow tint characteristic of the phenol resin, and from the viewpoint of the degree of freedom of coloring,
A water-soluble melamine resin is more preferable than a water-soluble phenol resin.

[0022]

According to the composition for artificial stone of the present invention, it is possible to use a conventional organic solvent and a curable resin simply by kneading with water without using an organic solvent which is unfavorable in the working environment. It is possible to easily obtain an artificial stone having a strength comparable to that of the obtained artificial stone and a texture of natural stone.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI C04B 14:10) (C08L 61/06 C08K 3:34 5:09) C04B 111: 54 (56) References JP-A-59-59 86655 (JP, A) JP-A-53-85884 (JP, A) JP-A-59-189162 (JP, A) JP-A-5-125219 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C04B 26/12 C08L 61/06 C08L 61/28 C04B 24/06 C04B 14/10 C04B 24:06 C04B 14:10 C08L 61/06 C08K 3/34 C08K 5/09 C08K 3:34 C08K 5:09

Claims (2)

(57) [Claims] 1. A composition for artificial stone, comprising metakaolin, citric acid and at least one of a water-soluble melamine resin and a water-soluble phenol resin. 2. The artificial stone material composition according to claim 1, wherein the metakaolin is formed by dehydrating a natural or artificial kaolinite by heating.