JPS61201631A - Production of crystallized glass article - Google Patents

Abstract

PURPOSE:To obtain the titled article from the deposited and grown crystal which has the beautiful appearance like a natural stone, has not air foams and is dense and suitable for the building construction and the decoration by molding the specified molten crystalline glass, giving a craze with the thermal shock or the like and thereafter heat-treating it. CONSTITUTION:The molten glass consisting of by weight 39.5% SiO2, 20.0% Al2O3, 33.5% CaO, 0.5% K2O, 6.0% ZnO and 0.5% As2O3 which is obtained by melting silica powder, Al2O3, CaCO3, KNO3, ZnO and arsenious acid or the like at 1,400 deg.C for about 5hr is flowed into a molding box made of metal to mold it to a platy shape and thereafter it is held at 650-680 deg.C for about 30min in an annealing furnace and is descended in temp. up to about 300 deg.C in about 1 deg.C/min velocity and transferred into a refractory molding box 1 coated with a mold release agent powder 2 on the inside surface and water is sprayed on the whole parts of the molded article to give the thermal shock and thereby the crazes 4 are formed. After drying it and rising it in temp. up to about 1,050 deg.C in about 200 deg.C/hr velocity in a heat-treating furnace, it is held for about 3hr to heat-treat it and the titled crazed article 3 is obtained by depositing and growing the crystal toward the inside part from the surface of the molded article and the boundary surface of the crazes.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for manufacturing a crystallized glass article suitable for natural stone-like artificial stone materials for architectural and decorative purposes.

[Conventional technology]

The methods for manufacturing natural stone-like crystallized glass articles known so far can be broadly divided into two types. One of them is Special Publication No. 47-1639, Special Publication No. 47-14-839, Special Publication No. 49-36376, Special Publication No. 51-23966,
Special Publication No. 53-41693, Special Publication No. 57-20254,
It is a method of directly crystallizing glass formed by the roll-act method, press method, pouring method, etc., which is substituted by JP-A-59-92942 and JP-A-59-97551. The other one is Special Publick No. 55-2901.
As proposed in Publication No. 8, after a plurality of pulverized glass particles are accumulated, the glass particles are softened, fused, and integrated with each other by heat treatment, and crystals are precipitated from the surface of the glass particles and from the fused area. This is a method called a sintering method in which a crystallized glass article is obtained by growth.

[Problems to be Solved by the Invention] In normal manufacturing methods, such as the roll-out method, press method, pouring method, etc., in which glass is formed by method 1 and then heat-treated to crystallize it, crystals spread throughout the molded product. Since the crystallized glass precipitates and grows almost uniformly, the appearance of the obtained crystallized glass article tends to be uniform and monotonous, which has the drawback that it is difficult to obtain an appearance similar to natural stone. On the other hand, the sintering method enhances the beautiful natural stone-like appearance due to the coexistence of crystals and glass matrix phases and the orientation of the crystals that grow from the surface of each glass grain or the fused interface toward the inside. Although this sintering method is much more preferable than the conventional molding method, this sintering method also has the following drawbacks.

(a) The glass grains must have a sufficiently low viscosity, and the glass grains must be completely softened, fused, and integrated with each other before crystal precipitation and growth from the surface becomes dominant, and the composition range must naturally be is limited. Furthermore, this also limits the type and crystallization of precipitated crystals and the physical properties of the glass article within narrow ranges.

(b) Even with the same composition and the same heat treatment conditions, the progress of softening and crystal precipitation due to heat treatment is different between when powder or fine glass particles are used and when relatively thick glass particles are used. On the other hand, since reproducibility cannot be obtained in the surface condition and appearance of crystallized glass articles, a process of smoothing using a sieve is required to make the particle size of the glass grains used almost constant.

e→ Even if the glass grains are sufficiently softened and fused by the heat treatment, some of the air gaps that exist between the glass grains during accumulation are inevitably taken into the interior of the crystallized glass article as pores. This is because when processing such as cutting or polishing is performed, the pores are exposed on the surface, and a crystallized glass article with a smooth surface cannot be obtained, and the mechanical strength is reduced.

[Purpose of the invention]

The present invention has a beautiful natural stone-like appearance due to the coexistence of crystals and matrix glass phases and the orientation of crystals precipitated and grown in the glass. It is an object of the present invention to provide a method for manufacturing a crystallized glass article for artificial stone, which solves all of the various drawbacks.

[Means for solving problems]

The gist of the present invention, which has been made to achieve the above object, is a process of forming crystalline glass into a desired shape, which has the property that crystals precipitate and grow from the surface toward the inside when heat treated. , a step of creating small cracks in part or the whole of the glass molded product by thermal shock or mechanical shock while maintaining the shape of the glass molded product, and then heat treatment to crack the glass molded product machine part and the crack boundary surface. It has a beautiful natural stone-like appearance due to the coexistence of crystals and matrix glass phases, and the orientation of the crystals, and is characterized by the process of precipitating and growing crystals toward the inside. There is no manufacturing method for fine crystallized glass products. “The crystalline glass used in the present invention may have a known composition as described in the above-mentioned publication, or may be of other types, and the present invention method is limited by the glass composition. The method of the present invention will be explained in detail below. First, crystalline glass having a property of precipitating and growing needle-shaped, dendritic, etc. crystals from the surface to the inside by heat treatment is melted, and then the roll-out method is performed. It is formed into a plate shape or a professional shape using conventional molding techniques such as the 'res method and the pouring method.Next,
While maintaining the shape of the thus obtained plate-like or professional glass molded product, a sudden thermal shock or mechanical shock is applied to create fine cracks in the whole or a part of the glass molded product. As a specific example, the following method can be considered.

(a) After cooling the formed glass article in a slow cooling furnace to a temperature of 300 to 500 °C at a rate that does not break,
A method in which the glass molded product is directly immersed in water to create cracks. If the glass molded product is large and thick, it is likely to lose its shape under its own weight, so rather than immersing it in water, it is better to transfer it to a fire-resistant formwork for crystallization heat treatment, whose inner surface has been coated with mold release agent powder, and then immerse it in water. It is preferable to apply a coating to create cracks. Moisture is removed by drying before heat treatment. The appearance and fineness of cracks can be controlled by the immersion method, water application method, and quenching temperature difference.

(b) The molded glass article can be used, for example, in Glass Handbook, edited by Masao Sakuhana, Teruo Sakaino, and Katsuaki Takahashi (
After air-cooling and strengthening the glass molded article as described in September 30, 1983), Shokusho Shoten, P. 485-490, the glass molded article is then strengthened with a large machine by hitting with a hammer or applying press pressure. A method of creating small cracks by applying a targeted impact. When applying impact, etc., in order to prevent small glass pieces from scattering or the shape of the molded product to be distorted, coat the front and back surfaces of the tempered glass molded product with glass shatter prevention spray in advance, and then apply a metal mold. It is preferable to fix it within a frame. If the glass molded product is large and thick, it will easily lose its shape under its own weight, so after making the cracks, a binder such as a polyvinyl alcohol aqueous solution is applied to the surface of the cracked glass molded product and dried and solidified. While maintaining its shape, transfer it into a fireproof mold coated with mold release agent powder. Further, in addition to a binder such as a polyvinyl alcohol aqueous solution, an adhesive tape or the like may be used.

Of course, methods (a) and (b) above apply to tempered glass products.

This can be applied to both unreinforced f-glass products.

When the glass molded product that has been cracked due to the above treatment is transferred to a heat treatment furnace along with the refractory formwork and heated, the cracks inside the glass molded product begin to fuse as the glass softens and become acicular, dendritic, etc. Crystals begin to precipitate and grow inside the glass molded product through cracks (interfaces) extending over the surface and the entire glass molded product, and when the heat treatment is continued, the entire product becomes a coarse aggregate of crystals. When a crack is placed in a part of a glass molded article, the crystals tend to be unevenly distributed, producing a unique design effect.

[Embodiments of the invention]

Examples of the present invention will be described below. FIG. 1 shows a state in which a cracked glass molded product 3 is filled into a fire-resistant mold 1 via a coating layer 2 of mold release agent powder for crystallization heat treatment in the method of the present invention. . 4 is a crack.

On the other hand, FIG. 2 shows a case in which glass particles 5 are filled by a sintering method. 6 is a void between glass particles.

Example 1゜ Silica powder, aluminum hydroxide, calcium carbonate.

A glass patch is prepared using potassium nitrate, zinc white, and arsenous acid as raw materials so as to satisfy the following glass composition, and the glass patch is placed in a crucible and melted at a temperature of 1400° C. for about 5 hours in an electric furnace. 5iOz 39.5 wt%, At20.20.0w
t%.

CaO33,5wt'J, K2O0,5wt%+
Zn06. Owt%-A! The molten glass obtained at 12030.5 wt% was poured into a metal mold and 300×30
Form into a plate shape of about 0x20mm.

This sheet glass was heated to 650 to 680°C for 30°C in a slow cooling furnace.
After holding for a minute, the temperature was lowered to aoo'c at a rate of 1°C/-, and the sheet glass was immediately transferred into a fire-resistant mold whose inner surface was coated with mold release agent powder (see Figure 1). ), the entire sheet glass molded product is subjected to thermal shock by pouring water on it to form cracks.

After that, the refractory formwork and the cracked molded product were dried and transferred to a heat treatment furnace at 200°C/200°C until the temperature reached 1050°C.
Heat treatment was performed by increasing the temperature at a rate of 1 hour and holding it at 1050°C for 3 hours.

As the temperature rises, cracks inside the glass molded product begin to fuse as the glass softens, but as the temperature rises above 900°C, cracks on the surface of the glass plate and cracks inside the molded product start to fuse together. Dendritic crystals began to grow from the interface toward the inside of each, and when the heat treatment was continued, a dense, bubble-free aggregate of coarse dendrites □ was formed. Of course, the crystallization rate can be changed within a certain range by changing the heat treatment conditions.

As a result of X-ray diffraction measurement, it was found that the main crystal of the precipitated crystal phase was gehlenite.

This natural stone-like pattern is caused by the mixture of crystals and matrix glass phases and the orientation of the crystals, as is the case with the accumulation method, but when the upper surface of the Crystallized Plus product is polished, a beautiful natural stone-like pattern is created. There were no pores exposed on the surface. For comparison, using a glass with the same J-lase composition as in Example 1, glass grains of about 2 to 6 wm were added to the second layer.
A crystallized glass article was manufactured by the sintering method shown in the figure.

Conditions such as heat treatment were the same as in Example 1.

The results of comparative tests between the above Example 1, Comparative Examples, and natural stones are shown in Table 1 below.

In Table 1, internal pores are determined by observing the cut or polished surface, acid resistance test is determined by observing the external appearance after immersion in 5% HCL (room temperature) for 24 hours, and bending strength is determined by 110X10X50. This shows the results of measuring the sample using a three-point loading strength tester.

As is clear from Table 1, the crystallized glass article has sufficient physical properties to be used as architectural and decorative materials, but according to the manufacturing method of the present invention, the upper surface of the crystallized glass article Since the glass is always smooth, it has the effect of shortening the time required for the polishing process.Also, even if the glass composition has a fast crystallization rate and is difficult to soften and fuse, a dense internal structure can be obtained. Since there are no pores, there is no need to worry about the pores being exposed on the surface during polishing or cutting, and the bending strength is also higher than that of the sintering method, making it possible to obtain various effects that compensate for the drawbacks of the sintering method. .

Furthermore, when applying water to crack glass molded products, if you use an aqueous solution containing colored ions, such as a nickel chloride aqueous solution, instead of just water, you will not only get the cracks, but it will also penetrate into the cracks. It is also possible to obtain a natural stone-like crystallized glass article having a beautiful colored pattern caused by colored ions, and known methods for coloring (for example, adding metal oxide, spraying an aqueous solution containing the same, etc.) can be applied. .

Example-2゜A sheet glass molded in the same manner as in Example-1 was prepared in "Glass no Ndopuku" edited by Masao Sakuhana, Teruo Sakaino, and Katsuaki Takahashi.
As described in (September 30, 1980), Breakfast Shoten P, 488, after holding the metal handle vertically, rapid uniform heating and rapid air cooling are performed to strengthen the air cooling. After coating both sides of this tempered glass plate with a commercially available glass shatter prevention spray (Topiteran Nippon Yushi Co., Ltd.), firmly fix it in the metal frame. Obtain beautiful radial fine cracks. Next, 15 seconds of polyvinyl alcohol aqueous solution was poured onto the surface of the cracked 9-glass plate, dried and solidified using an infrared ray, and then taken out from the metal formwork while maintaining the shape of the 75-glass plate, and heat treated. Transfer to a fireproof formwork. When this was heat-treated in the same manner as in Example-1, a very beautiful natural stone-like crystallized glass plate having a radial pattern was obtained. This crystallized glass article exhibited the excellent physical property values shown in Example-1 in Table 1.

In addition, as described in Example 1, after mechanical impact is applied to the air-cooled strengthened product to create cracks, a radial colored pattern can be created by applying an aqueous solution containing colored ions such as a nickel chloride aqueous solution. A natural stone-like crystallized glass article having the following properties is obtained.

〔Effect of the invention〕

According to the method of the present invention, even if the glass composition does not have a sufficiently low viscosity, the glass regions separated by cracks are in complete contact with each other and are easily fused or sintered. Easily integrated into original shape
Can be restored. Therefore, the sintering method, which does not require the glass composition to have a sufficiently low viscosity and can accommodate a wide range of glass compositions, requires a process to make the particle size of the glass grains used almost constant, and especially during the process. Handling of the resulting powder or fine glass particles is troublesome, but according to the manufacturing method of the present invention, although a step is required to crack the glass molded product, it is possible to handle the cracked glass molded product as is. This eliminates the need to handle powdered glass or fine glass, and as mentioned above, the type and size of cracks can be easily controlled by changing the degree of air-cooling strengthening during quenching temperature differences. Since the glass regions separated by the cracks are completely in close contact with each other, it can be said that there are almost no voids between the glass regions compared to the case of the sintering method. Therefore, the crystallized glass article obtained by heat treatment has a dense structure without pores. This eliminates the problem of exposing pores on the surface of the crystallized glass article during processing such as cutting or polishing, and also leads to an increase in mechanical strength. It has various excellent effects such as, and its usefulness is extremely large.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the state of a glass molded article before crystallization heat treatment according to the method of the present invention, and FIG. 2 is an explanatory diagram of a case using a conventional glass grain sintering method. ) - - Possible (Koji Niibe

Claims (1)

[Claims] A process of forming crystalline glass, which has the property of crystals precipitating and growing from the surface to the inside when heat treated, into a desired shape, and a process of forming the glass by thermal shock or mechanical shock while maintaining the shape of the glass molded product. A method of forming crystals, which is characterized by comprising a step of creating fine cracks in part or the whole of a molded product, and a subsequent step of precipitating and growing crystals from the surface of the glass molded product and the crack interface toward the inside through heat treatment. A method for producing a dense crystallized glass article having a beautiful natural stone-like appearance due to the presence of a matrix glass phase and crystal orientation, and having no air bubbles.