JPH0575701B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for producing crystallized glass having a color pattern. (Prior art) Conventional crystallized glass is generally produced by melting a glass raw material containing a nucleating agent, molding it using various molding machines, etc., and then subjecting it to crystallization heat treatment to precipitate crystals. It has a white color. Colored crystallized glass can be produced by adding a glass coloring agent to the above raw materials. Another method for obtaining crystallized glass is to obtain glass bodies by crushing molten glass by water cooling, etc.
A method of fusing and crystallizing each glass body by accumulating the core glass bodies in a mold and heat-treating them (hereinafter referred to as the accumulation method) was developed in ``Japanese Unexamined Patent Application Publication No. 1973-1989.
78217'', and the crystallized glass produced by this method is white with patterns due to non-uniform crystal growth. In addition, also in this accumulation method, it is also possible to obtain colored crystallized glass by using colored glass in which a glass colorant is added to the raw material glass. (Problems to be solved by the invention) Generally, glass is a material with a problem in terms of strength, and improvements in its strength are always sought after.Also, the diversification of decorative materials, construction materials, etc. has caused uniformity in colored glass as well. Glass that is not colored but has a change,
For example, the appearance of glass exhibiting a mottled pattern is expected, and from this point of view, the glass raw material containing the nucleating agent and glass coloring agent is melted and formed, and then crystallized by heat treatment for crystallization. The problem with the precipitation method is that the nucleating agent is expensive compared to the raw material, as well as uniform coloring, and the next accumulation method produces patterns due to non-uniform crystal growth as described above. transformation takes place,
When the glass bodies are heated, it is not suitable unless the glass bodies have a sufficiently low viscosity that they can be fused together at the temperature at which the crystals precipitate. As such, there are limitations to the raw material glass, and therefore colorants that also act as nucleating agents or nucleating agents, such as FeS+MnS, FeO+
Glass bodies containing Fe ₂ O ₃ etc. cannot be used. In other words, in a heated glass body, the growth rate of the crystal nuclei precipitated at the softening temperature is fast, and if the composition is such that the crystals grow before fusion, or if it contains a nucleating agent as described above, The viscosity increases due to the growth of crystals, and the individual glass bodies cannot be fused and integrated, and if an attempt is made to further increase the temperature to achieve integration, the crystals will instead break or transfer, resulting in crystallized glass. It doesn't become. However, with this accumulation method, there are problems in that the color does not come out clearly even when colored with a coloring agent that does not act as a nucleating agent, and there is also the problem that relatively large air bubbles (diameter) may occur inside the product.
It has the problem that it contains particles (more than 0.5 mm). (Means for Solving the Problems) The present invention solves the problems of the prior art as described above without requiring any special ingredients, and makes it possible to provide crystallized glass with a mottled color pattern. As a means for that purpose, SiO ₂ is added as an essential component in weight percentage, from 45 to 75.
%, _Al2O3 : 20% or less, CaO: 5-40 _% , _Na2O
+ _K2O : 2-20%, _SiO2 + _Al2O3 + _CaO +
A glassy raw material containing Na ₂ O + K ₂ O > 85% is crushed to produce 90 particles of 200 mesh or less.
% or more, each component in the composition range and a colorant in a weight percentage of 10% or less by pulverizing a raw material in a colored glass state,
When mixing the powder containing particles of 10 to 200 mesh or 10 to 200 mesh and smaller, mix the two at a desired ratio within the range in which particles of 200 mesh or smaller account for 50% or less in the mixture, Next, the mixture is compression-molded into a compact having a true density of 55% or more using a compression molding frame of a desired shape, and then heat-treated to soften and fuse the glass powders of the core compact to each other. The aim was to integrate and densify the material, while also crystallizing it, so that wollastonite crystals were mainly precipitated. (Function) The most characteristic technical means of the present invention is to form a glassy raw material into a fine powder, which is then heated in the form of a dense compression molded body, to soften and fuse each glass powder to integrate and densify it. On the other hand, with regard to crystallization, the pulverization of the glassy raw material and the creation of a densely compressed body work to facilitate softening and fusion between the glass powders at relatively low temperatures. It is. In other words, when coarse glass particles are heated, even when the softening point is reached, the particles are not immediately fused and integrated. First, the sharp corners of each particle begin to soften, and in order to soften almost the entire particle, it must be heated to a high temperature above the softening point, and it is only when heated to such a high temperature that fusion and integration occur. It is. However, in the case of a dense compacted body of fine powder, each particle is in close contact with each other over a large area relative to its mass, and it is extremely easy to fuse and integrate the particles, resulting in progress in densification. The fact that it has become possible to integrally densify glass particles at a relatively low temperature means that crystal growth can be achieved after integral densification, and this successfully solves the problems of conventional integration methods. Even if a nucleating agent or a coloring agent that acts as a nucleating agent is included, crystallization can be achieved after the green compact particles are densified, and furthermore, during the crystallization, the nucleating agent contained It works effectively. Figure 1 is a graph conceptually showing the relationship between temperature, nucleation rate, and crystal growth rate when heating a compressed glass fine powder, with the nucleation rate and crystal growth rate plotted on the vertical axis, and the horizontal axis. The temperature is maintained at the shaft. The broken line is the "nucleation rate-temperature" curve, and the solid line is the "crystal growth rate-temperature" curve. In addition, S.
P. is the softening point and MP is the melting point. As mentioned above, when heating a compacted glass powder, each glass particle is fused and integrated and densified at a relatively low temperature that does not exceed its softening point, and it is during this period that nuclei are generated. The graph shows that the number increases, and as the temperature increases thereafter, crystal growth becomes more active. Next, to mention another effect of forming a densely compressed body of fine powder, even if the composition of the glass is difficult to crystallize, that is, the glass has a composition where the crystal growth rate is slow, crystallization progresses relatively easily. It is to become like that. In other words, the crystallization rate is expressed as (crystallization rate) = (crystal nucleus number) x (crystal growth rate), and crystal nuclei are likely to occur at the fused interface between glass particles, and in a green compact of fine powder. The number of fused interfaces is large and wide, and therefore many nuclei are generated, and even if the crystal growth rate is not high, the crystallization rate is increased as a result. Another major feature of the present invention is that colorless glass powder and colored glass powder are mixed, and the colored glass powder particles are coarser than the colorless glass powder particles. In other words, the coarse grains act to form a mottled pattern. For example, similar fine particles of colorless and colored raw materials are used.
When mixed as fine particles of 200 mesh or less and manufactured as crystallized glass, the product exhibits a uniform color and does not have a mottled pattern. This makes the process of separately manufacturing colored and colorless raw materials and mixing the powders of each powder meaningless. (Example) First, the reason for limiting the essential components will be described. Note that the essential components are common to colorless and colored glassy raw materials. _SiO2 : 45 to 75% (weight percentages are the same) If it is less than 45%, it is difficult to maintain the shape of the compression molded product during heat treatment, and if it is more than 75%, the viscosity of the glass increases and the densification of the compression molded product becomes slow. Al ₂ O ₃ : 20% or less If it is 20% or more, the viscosity of the glass becomes high and the densification of the compression molded product becomes slow. CaO: 5-40% If it is less than 5%, crystals such as wollite night and anorsite will be difficult to precipitate. Moreover, if it exceeds 40%, physical properties such as water resistance and acid resistance will be affected. Ka ₂ O + K ₂ O: 2 to 20% If it is less than 2%, the viscosity of the glass increases and the densification of the compression molded product becomes slow. Moreover, if it exceeds 20%, it is difficult to maintain the shape of the compression molded product during heat treatment. The above-mentioned essential components are contained in a total amount of 85% or more in order to maintain appropriate physical properties as a glass. Next, coloring agents (CoO, FeO + Fe ₂ O ₃ , Cr ₂ O ₃ , NiO, CuO,
Regarding the reason why MnO ₂ etc.) was set to 10% or less,
From the viewpoint of coloring, a content of 10% or more is not only unnecessary, but also a content of 10% or more increases the difference in physical properties from a colorless glassy raw material. Next, regarding non-essential components, up to 2% of each of MgO, ZnO, BaO, PbO, B ₂ O ₃ , etc. can be added to both colorless and colored glass raw materials without any problem, and Sb ₂ O ₃ can be used as a fining agent. 1% or less may be added at the time of melting. It is also possible to contain a nucleating agent. Next, the manufacturing method will be explained in detail. Colorless and colored glassy raw materials are produced by mixing and melting the raw materials for each of the above components to a predetermined composition, and then quenching and crushing this by a method such as water pulverization to obtain glassy bodies. Use as raw material. Of course, a material having a limited range of component compositions and already in the form of glass may be used as the raw material, and this may be crushed into small bodies by an appropriate means. The glass bodies thus obtained are further crushed using, for example, a ball mill, and at this time, the colorless glassy raw material (hereinafter referred to as colorless raw material) is made to contain 90% or more of fine particles of 200 mesh or less. , colored glassy raw materials (hereinafter referred to as colored raw materials) are powders of 10 to 200 mesh, or
The powder must contain powder of 10 to 200 mesh and further contain fine powder of 200 mesh or less. The thus obtained colorless and colored raw material powders are mixed, and both are mixed in a desired ratio so that fine powder of 200 mesh or less accounts for 50% or more of the mixed powder. The reason why we limited 200mesh or less to 50 or more is because if it is 50% or less, that is, if there are many coarse particles mixed in, it will affect dense compaction and raise the temperature for fusing and integrating the particles. At the same time, if the particle size and amount of the coarse colored raw material powder becomes large, air bubbles will be included inside the product. This is because, as mentioned above, the product tends to contain air bubbles, which may reduce its strength. However, in cases where strength and the presence of bubbles are not a problem, some amount of the coarse particles may be allowed. Next, the mixed powder is compression-molded into a dense green compact with a true density of 55% or more using a compression molding frame of the desired shape. This is to ensure that densification is performed at low temperatures, and in order to compression mold glass powder with the above particle size to a density of 55% or more of the true density.
A pressure of 20 Kgf/cm ² or more is suitable. Note that when compression molding the powder, it is effective to add a small amount of a binder such as polyvinyl alcohol (PVA) to the powder in advance to facilitate molding. The green compact obtained in this way is heated to a temperature above the softening point (actually, preferably above the softening point + 100°C) and below the temperature at which the crystal growth rate increases in order to fuse and integrate the glass particles and make it densified. Heat treatment is performed.
Through this treatment, each glass powder is fused and integrated and densified, and at the same time, nucleation is progressing at the fused interface between the particles. Once the compact has been densified, the temperature is further increased to encourage crystal growth and crystallization, but as mentioned above, the mixed colored raw material powder has a different composition compared to the colorless raw material powder. Since the composition contains only 10% or less of a coloring agent, there is no significant difference in the softening point or other properties of the two raw material powders, and the integral densification and crystallization of the powder proceed without any problems during the heat treatment described above. FIG. 2 shows the heat treatment curve of the above-mentioned green compact, in which the interval aa is the integral densification section of the glass particles, the interval bb is the crystallization section, SP is the softening point, and MP is the melting point. The crystallized glass obtained through the above steps is
The rest is white due to crystal precipitation, and the colored parts are distributed in a patchy manner. Depending on the degree of mixing of the powder, the colored part can be a fine speckled pattern with a uniform distribution, or a lump-like pattern with an uneven distribution. It is possible to make it exhibit a mottled pattern, and it is also possible to adjust the density of the mottled pattern by changing the mixing ratio of colored and colorless raw material powders. It is also possible to create a multicolored mottled pattern by using multiple types of colored raw materials with different colors. Next, specific examples of the present invention will be shown. The colorless and colored raw materials used in the examples have the compositions shown in the table below.The raw materials containing each component were dissolved at 1500℃, and then poured into water to form colorless and colored raw materials, respectively. Glassy bodies were obtained.

[Table] The glass bodies were crushed using a ball mill,
The following powder was prepared. Colorless raw materials are powders of 200mesh or less Colored raw materials are (40-200mesh powders): (200mesh
The following powders) = Powders containing at a ratio of 1:2 Mix both of the above powders at a ratio of 1:1, add 5w.t% of a 3% solution of PVA as a binder, and use a compression molding frame. A compression molded body of 100×100×25 (mm) was obtained. Although the press pressure during molding was 30 Kgf/cm ² , no difference was observed in the physical properties of the heat-treated products. The above compression molded body was heat-treated by increasing the temperature to 690℃ at a rate of 150℃/hr and maintaining the same temperature for 30 minutes to fuse and integrate the glass powder, and then
When the temperature was raised to 800℃ and the same temperature was maintained for 30 minutes to achieve crystallization, the product turned into wollastonite (CaO.
It was observed that crystals of SiO ₂ ) were precipitated. Figure 3 shows the heat treatment curve of the above heat treatment, and the physical properties of the crystallized glass obtained by the same treatment are density 2.5Kg/cm ² , water absorption 0.02%, and bending strength 710Kgf/cm 2 .
It was warm in ^cm2 . Note that FIGS. 4 and 5 are diagrams of the pattern structure of the crystallized glass obtained in the above example, and
The figure shows the case where the raw glass powder is mixed uniformly, and the colored part exhibits a fine speckled pattern with fine and uniform distribution, and Figure 5 shows the case where the raw glass powder is mixed unevenly, and the colored part has a lumpy mottled pattern. . (Effects of the Invention) As described above, the method of the present invention heat-treats a fine powder of a glassy raw material as a compression molded body, thereby eliminating the problem of increased viscosity due to crystal growth unlike in the accumulation method. Glasses with a wide range of compositions (the composition range specified in the present invention is wide, and many conventional glasses fall within this range) can be easily crystallized, and coloring can be achieved by mixing colored glass powder and colorless glass powder. Because it is heat treated as a green compact, it is possible to create a mottled pattern, and the pattern changes depending on the color, particle size, amount, degree of mixing, etc. of the colored glass particles.
Furthermore, it can be varied in various ways depending on the degree of crystallization. In addition, since it is molded as a powder compact, it can be easily formed into a desired shape, and it is also easy to form irregularities on the surface. Furthermore, it is a great advantage as a material that it can be manufactured without including many air bubbles inside the product, making the strength of crystallized glass even more reliable. The process value of the present invention, which has various advantages as described above and makes it possible to provide colored patterned crystallized glass as an excellent decorative material and building material, is enormous.

[Brief explanation of the drawing]

Figure 1 is a graph conceptually showing the relationship between temperature, nucleation rate, and crystal growth rate when a compacted glass powder is heated; the broken line graph is the ``nucleation rate-temperature'' curve, and the solid line graph is “Crystal growth rate-
temperature” curve. FIG. 2 shows a heat treatment curve showing the heat treatment mode in the present invention, and FIG. 3 shows a heat treatment curve of an example of the present invention. 4 and 5 are diagrams showing the pattern structure of crystallized glass according to an example of the present invention. FIG. 4 shows the crystallized glass obtained when the raw material glass powders are uniformly mixed, and FIG. This is a crystallized glass obtained when uniformly mixed.

Claims (1)

[Claims] 1 As an essential component, SiO ₂ : 45 to 45% by weight
75%, _Al2O3 : 20% or less _, CaO: 5-40%,
Na ₂ O + K ₂ O: 2 to 20%, SiO ₂ + Al ₂ O ₃ + CaO
A glassy raw material containing +Na ₂ O + K ₂ O > 85% is crushed to produce particles of 200 mesh or less.
A colored glass-like raw material comprising a powder that accounts for 90% or more, each component in the above composition range, and a coloring agent of 10% or less by weight is pulverized to produce 10 to 200 mesh or 10 to 200 mesh. When mixing powder containing 200mesh and smaller particles,
In the mixture of both, there are 50 particles of 200 mesh or less.
% or less in a desired proportion,
Next, the mixture is compression-molded into a compact having a true density of 55% or more using a compression molding frame of a desired shape, and then heat-treated to soften and fuse the glass powders of the core compact to each other. 1. A method for producing crystallized glass with a colored pattern, characterized in that crystallization is achieved while integrating and densifying the glass, so that wollastonite crystals are mainly precipitated.