JPH0360784B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for producing pyroxene-based crystallized glass. [Prior Art] Wollastonite-based crystallized glass and forsterite-based crystallized glass with marble patterns have been proposed as building materials such as wall materials. Wollastonite-based crystallized glass is produced by forming molten glass into a plate shape or pouring it into a predetermined mold and crystallizing it, so that wollastonite crystals grow perpendicular to the surface of the glass and its shape is needle-like, so
Even if the surface is polished, marble patterns are unlikely to occur. Therefore, such crystallized glass is produced by crushing molten glass by water cooling or other means to obtain glass particles.
It is manufactured by the so-called stacking method, in which it is placed in a predetermined mold, subjected to crystallization treatment, and then polished to form a pattern. However, the accumulation method requires a glass grain manufacturing process, which has the disadvantage of complicating the process. On the other hand, the latter forsterite-based crystallized glass has a high devitrification temperature of 1350° C. or higher, so it has the disadvantage that it is more difficult to produce a molded body of a predetermined shape than molten glass. [Problems to be Solved by the Invention] The object of the present invention is to provide a method for producing pyroxene-based crystallized glass with a natural stone pattern, which does not require a glass crushing step and has a devitrification temperature of 1300° C. or less. [Means for solving the problem] The present invention provides SiO ₂ 55 to 68% by weight,
Al ₂ O ₃ 3 ~ 15, SiO ₂ + Al ₂ O ₃ 62 ~ 78, CaO 3 ~ 8,
MgO8~13, CaO+MgO11~19, _Na2O4 ~15,
Li ₂ O0～3, K ₂ O0～5, Na ₂ O＋Li ₂ O＋K ₂ O4～
15, _TiO2 0.2~3, ZnO0~8, _{B2O3 0} ~5,
Forming glass into a predetermined shape, consisting of P ₂ O ₅ 0 to 5 and having a weight ratio of MgO/CaO of more than 2/3,
A method for producing crystallized glass is provided, in which the molded body is heated to generate pyroxene crystals. The crystallized glass produced in the present invention contains diopside (CaMgSi ₂ O ₆ ),
Aluminum-containing diopside and enstatite (MgSiO ₃ ) are produced by replacing a portion of MgSi in diopside with Al. The content of such crystals is about 20 to 50% by weight. The reasons for limiting the glass composition of the molded body used in the present invention are as follows. SiO ₂ becomes a component of pyroxene crystals and a component of the glass phase. When SiO ₂ <55% and SiO ₂ >68%, it is difficult to obtain the crystallized glass product, and the viscosity makes it difficult to form a plate by a roll-out method or the like, and both are unfavorable. Al ₂ O ₃ has the effect of improving weather resistance, the effect of promoting crystal nucleation, and is one of the constituent components of pyroxene crystals. When Al ₂ O ₃ <3%, these effects are insufficient. When Al ₂ O ₃ >15%, other crystals such as forsterite and cordierite are formed, and the meltability deteriorates, which is not preferable. When SiO ₂ +Al ₂ O ₃ >78%, the meltability of the glass deteriorates, and when SiO ₂ +Al ₂ O ₃ <62%, the weather resistance of the glass decreases, both of which are unfavorable. CaO is a component of pyroxene crystals. CaO>8% is not preferable because the generation of crystal nuclei is suppressed and crystal growth from inside is not achieved. CaO<3% is not preferable because the above crystals are difficult to precipitate. MgO is a component of pyroxene crystals. MgO<8%
Well then. The crystals are difficult to form, crystals other than the crystals (wollastonite, anorthite) are formed, the generation of crystal nuclei is suppressed, and crystal growth from the inside is not achieved, resulting in a decrease in strength. MgO＞12
%, enstatite is likely to be generated when molten glass is molded into a plate shape, making the molding difficult. When CaO+MgO>19%, wollastonite crystals are formed and cracks are likely to occur;
If MgO>11%, the amount of formed crystals is small and the strength is low, which is not preferable. Among the above ranges, CaO+MgO is more preferably in the range of 11 to 19. NaO ₂ improves the solubility and formability of raw materials into plate shapes, and accelerates crystal growth. When Na ₂ O is less than 4%, the solubility is poor, the viscosity is high, and the moldability is reduced.
When Na ₂ O>15% or more, the viscosity is too low, and the moldability and weather resistance are reduced.
The content of Na ₂ O is particularly preferably 6 to 12% within the above range. Like Na ₂ O, K ₂ O improves solubility and formability into plate shapes, and has a composite alkali effect (Na ₂ O + K ₂ O)
Improves weather resistance. K ₂ O > 5% is not preferable because crystals occur during molding and the price is high. _K2O
is particularly preferably 0 to 3% within the above range. Like Na ₂ O, Li ₂ O improves meltability and formability into plate shapes, and has a composite alkali effect (Na ₂ O + Li ₂ O).
Improves weather resistance. Li ₂ O > 3% is undesirable because it is expensive. Li ₂ O is 0 to 0 in the above range
2% is particularly preferred. In addition, 4 to 15% of Na ₂ O + K ₂ O + Li ₂ O is good;
Furthermore, 6 to 12% is particularly preferred. TiO ₂ is a crystal nucleating agent and generates crystals from within the glass, thereby improving the strength of the crystallized glass. Furthermore, this component acts to grow crystals to a size that provides an excellent appearance as a natural stone pattern. When HiO ₂ <0.2%, this effect is hardly obtained, and when TiO ₂ >5%, the crystals are colored grayish-purple, which is not preferable. TiO ₂ is within the above range
Particularly preferred is 0.2-3%. ZnO improves chemical resistance and improves the strength of the crystallized glass. ZnO>8% is undesirable because the meltability deteriorates and other crystals (zinc spinel) are formed and colored dark blue. _B2O3 promotes solubility _and reduces viscosity.
If B ₂ O ₃ >5%, phase separation of the glass tends to occur, which is undesirable because it delays the ceraming treatment time after molding. B ₂ O ₃ is particularly preferably 0 to 3% within the above range. P ₂ O ₅ promotes solubility and promotes crystal nucleation. On the other hand, when P ₂ O ₅ >5%, crystal growth slows down,
This is not preferred because it delays the ceramicing treatment time after molding. P ₂ O ₅ is particularly preferably 0 to 3 in the above range. Furthermore, if the weight ratio of MgO/CaO is less than 2/3, wollastonite crystals are formed and cracks are likely to occur, which is not preferable. In the present invention, the total amount of the above components is preferably 96% or more, and the remaining amount is less than 4%.
Coloring agents such as MnO ₂ , CaO, Fe ₂ O ₃ , NiO, Se, etc. can be added to create the desired color tone. In producing a glass molded body having such a composition, each raw material is mixed and batched so as to have a target composition, and the mixture is heated to 1400 to 1500°C in a melting furnace to melt and clarify. Next, the molten glass is cooled to about 1300°C and formed into a predetermined shape. When forming plate glass, there are no particular limitations, but in terms of productivity, it is best to continuously form a ribbon of a predetermined thickness using a roll-out method, then slowly cool it and cut it into a predetermined size. desirable. In order to generate crystals in such a molded body, it is desirable to employ the following heat treatment. The temperature is raised to a temperature at which crystals grow at a rate that does not damage the molded body, and the temperature is maintained in a normal atmosphere for 3 to 5 hours. As a result, diopsite, aluminum-containing diopsite, and enstatite are formed as main crystals in the glass. The temperature at which crystals grow is 950~
The temperature is 1050℃. 120-240 at 650-780℃ during heating process
Fine crystals can be generated by holding the temperature for a minute or by lowering the heating rate in the temperature range. The generation of fine crystals can also be achieved by adding a small amount of carbon to a glass raw material and melting it, and then crystallizing a molded body made from this molten glass. The size of the crystals produced by this method is about 0.1 to 4 mm,
In addition, the amount of crystals ultimately produced is 30 to 40% by weight.
It is. [Example] According to a conventional method, silica sand was used as the SiO ₂ source, alumina powder was used as the Al ₂ O ₃ source, and
Limestone as CaO source, magnesium hydroxide as MgO source, soda ash as Na ₂ O source, potassium carbonate as K ₂ O source, lithium carbonate as Li ₂ O source, titanium dioxide powder as TiO ₂ source, zinc white as ZnO source, A batch was prepared according to the desired glass composition using borax as a B ₂ O ₃ source and calcium phosphate as an R ₂ O ₃ source, and further using Glauber's salt and carbon as a fining agent. 5 kg of this batch was placed in a platinum crucible and melted at 1450°C for 5 hours, press-molded into a plate shape and cooled. The formed plate glass was placed on a base made of refractory material sprinkled with alumina powder, placed in a heat treatment furnace, heated at a rate of 50°C/hr, and crystallized at 1000°C for 4 hours. Next, the surface of this plate glass is roughly polished with silica sand,
Alumina fine powder gives it a shine. The devitrification temperature, bending strength, and crystal type measured for these glasses are also listed in the same table. Crystal type A in the table represents tapesite, B represents aluminum-containing dipsite, and C represents enstatite. As is clear from the table, the devitrification temperature of the glass used in the present invention is 1300
Since the temperature is as low as ℃ or less, it is easy to form glass products. Furthermore, when the surface of a crystallized glass molded article was observed, no cracks were observed at all. In addition, the glass had a natural stone pattern and could be used as a wall material. [Effects of the Invention] Since the crystallized glass according to the present invention develops crystals in various directions regardless of the glass surface, it is possible to form molten glass into a plate shape by a roll-out method or the like.
It can be manufactured by crystallizing and polishing as is. Therefore, the process of granulating the glass and placing it into a mold is simplified. Furthermore, since the devitrification temperature is as low as approximately 1250°C, it can be molded using the normal roll-out method, so there are fewer restrictions on manufacturing conditions. In addition, the crystallization treatment is also below 1000℃, from 950℃ to 1000℃.
℃, it also has the advantage of being able to use inexpensive materials for the base and the like.

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Claims (1)

[Claims] 1 Substantially SiO ₂ 55 to 68 , Al ₂ O ₃ in weight %
~ 15 , SiO ₂ + Al ₂ O ₃ 62 ~ 78 , CaO 3 ~ 8 , MgO
8-13 , CaO+ MgO 11-19 , _Na2O4-15 ,
Li ₂ O0～3, K ₂ O0～5, Na ₂ O＋Li ₂ O＋K ₂ O4～
15, _TiO2 0.2~ 3 , ZnO0~ 8 , _{B2O3 0} ~5,
Forming glass into a predetermined shape, consisting of P ₂ O ₅ 0 to 5 and having a weight ratio of MgO/CaO of more than 2/3,
A method for producing crystallized glass, which comprises heating the molded body to generate pyroxene crystals.