Porous building plate and method of jointing same

Abstract: A method of applying porous building plates by applying plate-like porous building plates having pores on the surface and then jointing them by means of a coated joint method, which comprises packing the pores on the surface of the porous building plates with an acid soluble substance, applying them and then jointing them by means of a coated joint method and, subsequently, washing the surface of the porous building plates with an acid.

Description: The present invention concerns a method of jointing porous building plates and, more specifically, it relates to a method of applying porous building plates, for example, to walls, floors or plates and then jointing them by a coated joint method. Document EP-A-0 066 002 discloses a method of protecting a porous ceramic tile surface whereby a coating is applied to the surface and subsequent to laying said tile the coating is chemically removed by means of a solvent. The coating and solvent are disclosed as comprising lacquer, wax or paraffin and an organic solvent, respectively. As a method of facing tiles, there is known a method of facing tiles, for example, to plates, walls or floors and then jointing them by means of a coated joint method. The coated joint method comprises coating a joint material in a slurry onto the entire surface of tiles including joint spaces and then washing out to remove the joint material deposited on the surface of the tiles. In the case of jointing tiles having pores on the surface by the coated joint method, the joint material is filled not only into the joint spaces but also into the pores on the surface of the tiles. The joint material filled into the pores on the surface of the tiles is difficult to remove even by subsequent water washing. Since tiles having pores on the surface filled with the joint material have different tone and feeling from those of usual tiles, they provide contaminated appearance for the surface of the applied tiles. A tile having pores on the surface is advantageous in that it is less slippy even when wetted with water since the surface is roughened by the pores. However, a tile having pores filled with joint material is flattened at the surface and so loses this advantage. It is an object of the present invention to provide a porous building plate which is suitable for use in a coated joint method. Another object of the present invention is to form a fine and less slippy surface for tiles applied. In one aspect, the present invention provides a method of applying porous building plates by facing plate-like porous plates having pores on the surface thereof and then jointing said plates by means of a coated joint method, which method comprises filling the pores on the surface of said porous building plates with an acid soluble substance formed of calcium carbonate, facing said plates, jointing the faced plates by applying a coated joint material in the form of a slurry onto the entire area of the thus-filled porous building plates and the joint spaces between the porous building plates so that said joint material fills the joint spaces and coats the surfaces of said building plates, washing the surface of the building plates with water so as to remove said joint material coated on the surface of said building plates, washing the surface of the building plates with an acid so as to dissolve said acid soluble substance thereby to remove said substance from said pores, and washing the surface of said building plates with water. In a second aspect, the present invention provides a method of applying porous building plates by facing plate-like porous plates having pores on the surface thereof and then jointing said plates by means of a coated joint method, which method comprises facing said porous building plates, filling the pores on the surface of said porous building plates with an acid soluble substance formed of calcium carbonate, jointing said plates by applying a coated joint material in the form of a slurry onto the entire area of the thus-filled porous building plates and the joint spaces between the porous building plates so that said joint material fills the joint spaces and coats the surfaces of said building plates, washing the surface of the building plates with water so as to remove said joint material coated on the surface of said building plates, washing the surface of the building plates with an acid so as to dissolve said acid soluble substance thereby to remove said substance from said pores, and washing the surface of said building plates with water. The invention also provides a plate-like porous building plate having pores on the surface, wherein said pores on said surface are packed with an acid soluble substance formed from calcium carbonate. A preferred method of applying porous building plates according to the present invention includes the following two methods (A) and (B). (A): (1) Filling pores on the surface of porous building plates with an acid soluble substance. (2) Facing the porous building plates subjected to the packing treatment in the step (1) above to a building body. (3) Jointing by a coated joint method. (4) Washing the surface of the porous building plates with water and washing out the joint material deposited on the surface of the porous building plates in the step (3) above. (5) Washing the surface of the porous building plate with an acid thereby dissolving to remove the acid soluble substance packed in the pores on the surface of the porous building plates. (6) Washing the surface of the porous building Plates with water again. (B): i) Applying the porous building plate to a building body. ii) Filling the pores on the surface of the applied porous building plates with an acid soluble substance. iii) Jointing them by a coated joint method. iv) Washing the surface of the porous building plates with water thereby washing out the joint material deposited on the surface of the porous building plates in the step (iii) above. v) Washing the surface of the porous building plates with an acid thereby dissolving to remove the acid soluble substance packed in the pores on the surface of the porous building plates. vi) Washing the surface of the porous building plates with water again. In particular, by method (A) described above, since porous building plates in which the pores on the surface are previously packed with the acid soluble substance are used, there is no need for longer treatment of the faced tiles. In the present invention, as the acid soluble substance to be packed in the pores on the surface of the porous building plate, those which are less soluble or insoluble to water and easily soluble to an acid are preferred. For instance, suitable are salts of a weak acid and a strong base such as calcium carbonate or calcium acetate. Among these, calcium carbonate is preferred since it is less expensive. To pack the acid soluble substance in the pores, an aqueous slurry containing about 10 to 50% by weight of the acid soluble substance such as calcium carbonate is prepared and the slurry is coated and dried on the surface of the porous building plate. The acid soluble substance such as calcium carbonate in the slurry is packed in the pores on the surface of the porous building plate. Thus, slurry joint material cannot enter into the packed pores. In the present invention, after facing the porous building plates, the conventional coated join method is applied. That is, a slurry joint material is at first coated to the joint space on the surface of the building plates. As the joint material, any commercially available material can be used. Cement type joint materials which have often been used, can be also employed in the present invention. After coating the joint material onto the surface of the building plates and the joint spaces, the surface of the porous building plates is washed with water to wash out the joint material deposited on the surface of the porous building plates. Subsequently, the acid soluble substance in the pores on the surface of the porous building plates is removed by dissolution with an acid. As the acid, a diluted solution of about 1 to 10% by weight of hydrochloric acid is preferably used in view of its handlability and easy availability. After washing with the acid, they are washed again with water to remove excess acid, dissolved joint material and a solution containing fine particles. To wash with water and acid, the surface of the porous building plates is wiped with a sponge impregnated with water or dilute hydrochloric acid, or water or dilute hydrochloric acid is sprayed onto the surface of the porous building plates for example, by spraying. The building plates after removal of the packed material by washing with acid and water have substantially the same surface as those of "usual" building plates before they are packed with the material. In the present invention, the porous building plate conveniently comprises a plate-like building plate such as a porous plate in which continuous pores or closed pores are exposed to the surface. The plate material may be porous throughout the entire portion or only at the surface layer. The invention will now be illustrated with reference to the following examples. EXAMPLES Example 1 Commercially available calcium carbonate (industrial powder) in the form of an aqueous 20 wt% slurry dispersion was coated on the surface of porous tiles (300 mm square) in which closed pores are opened at the surface, to pack calcium carbonate in the pores on the surface. The tiles were faced to a building block and jointed with a cement type joint material by means of a coated joint method. Subsequently, the joint material on the surface of the tiles was washed out by washing with water and then calcium carbonate in the pores on the surface of the tiles was washed with an aqueous 3 wt% of hydrochloric acid and removed by dissolution and then they were washed with water again. For the resultant tiles applied, lightness L* and hues a*, b* were measured and a color difference ΔE* ab was determined from the difference for each of the values of the tiles before application in accordance with the following equation. ΔE* ab = [(ΔL*)² + (Δa*)² + (Δb*)²] 1/2 = [(61.175-61.083)²+(-2.375-(-2.388))²+((2.268)-2.088)²] 1/2 = 0.20. Further, for the tiles at the applied surface, slipping resistance coefficient (CSR·B) was measured upon wetting with water and wetting with liquid soap, which was compared with the tiles before application. On the other hand, for the comparison, jointing was applied in the same manner except that the packing treatment and acid washing were not conducted, and measurement was conducted in the same manner as for the tiles on the applied surface. Then, the color difference ΔE* ab was determined as follows and the slipping resistance coefficient was measured in the same manner. ΔE* ab = [(ΔL*)² + (Δa*)² + (Δb*)²] 1/2 = [(62.268-54.618)²+(-3.61+2.978)²+(6.92-4.298)²] 1/2 = 8.11. The results are collectively shown in Table 1. From the foregoing results, the followings are apparent. For the tiles at the applied surface by the conventional method, since the pores were filled with the joint material, the tone was significantly changed as color difference of ΔE* ab = 8.11 from the tone of the tiles before application. On the other hand, the tone of the tile before the application according to the present invention shows no substantial change as: color difference ΔE* ab = 0.20 from the tone of the tiles before application. Also, with reference to the slipping resistance coefficient, since the pores on the surface of the tile were filled with the joint material, the roughened surface due to the presence of the pores was lost and it became remarkably slippy in the conventional method. Conversely the slipping resistance coefficient showed no substantial change from that before application and the roughened surface due to the presence of the pores was maintained in the present invention.

Claims: A method of applying porous building plates by facing plate-like porous plates having pores on the surface thereof and then jointing said plates by means of a coated joint method, which method comprises filling the pores on the surface of said porous building plates with an acid soluble substance formed of calcium carbonate, facing said plates, jointing the faced plates by applying a coated joint material in the form of a slurry onto the entire area of the thus-filled porous building plates and the joint spaces between the porous building plates so that said joint material fills the joint spaces and coats the surfaces of said building plates, washing the surface of the building plates with water so as to remove said joint material coated on the surface of said building plates, washing the surface of the building plates with an acid so as to dissolve said acid soluble substance thereby to remove said substance from said pores, and washing the surface of said building plates with water. A method as claimed in claim 1, wherein said acid is hydrochloric acid. A method as claimed in claim 1 or claim 2, wherein said calcium carbonate is coated in the form of a slurry on the surface of said building plates. A method of applying porous building plates by facing plate-like porous plates having pores on the surface thereof and then jointing said plates by means of a coated joint method, which method comprises facing said porous building plates, filling the pores on the surface of said porous building plates with an acid soluble substance formed of calcium carbonate, jointing said plates by applying a coated joint material in the form of a slurry onto the entire area of the thus-filled porous building plates and the joint spaces between the porous building plates so that said joint material fills the joint spaces and coats the surfaces of said building plates, washing the surface of the building plates with water so as to remove said joint material coated on the surface of said building plates, washing the surface of the building plates with an acid so as to dissolve said acid soluble substance thereby to remove said substance from said pores, and washing the surface of said building plates with water. A method as claimed in claim 4, wherein said acid is hydrochloric acid. A method as claimed in claim 4 or claim 5, wherein said calcium carbonate is coated in the form of a slurry on the surface of said building plate. A plate-like porous building plate having pores on the surface, wherein said pores on said surface are packed with an acid soluble substance formed from calcium carbonate.

Inventors: HONDA TOMONORI, KITAHARA SHOJI, KOYAMA AKIHISA, HONDA, TOMONORI, KITAHARA, SHOJI, KOYAMA, AKIHISA
Applicants: INAX CORP, INAX CORPORATION
Application year: 1992
Main classification: E04F15
IPC codes: E04F15, E04F13