Stock material or miscellaneous articles – Composite – Of quartz or glass
Reexamination Certificate
2002-10-04
2004-05-18
Jones, Deborah (Department: 1775)
Stock material or miscellaneous articles
Composite
Of quartz or glass
C428S426000, C428S428000, C501S032000, C501S104000
Reexamination Certificate
active
06737166
ABSTRACT:
TECHNICAL FIELD
The present invention relates to sanitary ware such as washhand basins, wash bowls, urinals, stools, toilet tanks, toilet strainers, and the like.
BACKGROUND ART
Such sanitary ware as washhand basins, wash bowls, urinals, stools, toilet tanks, toilet strainers, and the like are daily necessities, and are required to have such a sufficient mechanical strength that even a very heavy person can use, while resting the person's weight, some of these articles without anxiety. In addition, a good quality of design is also required.
Furthermore, the above mentioned commodities are used in the portions of a house where water is used, and hence these commodities are required to have chemical stability.
Accordingly, from old times, glazed ceramic wares have been used as sanitary ware, and particularly, glazed ironstone bodies and glazed vitrifiable bodies have been generally used for sanitary ware which bodies can be fired at such temperatures 1100 to 1300° C. that easily allow to acquire in a single firing the degree of freedom in design based on the coloring and patterns brought forth by the glaze layer, and which bodies can also display sufficient mechanical strengths.
As for the ironstone bodies and vitrifiable bodies, however, when these bodies are fired to shrink to such an extent that a satisfactory mechanical strength is displayed, the shrinkage when fired becomes large and the deformation when fired also becomes great.
Accordingly, it is difficult to design accurately the dimension and shape of a product after being subjected to firing, and hence there are restrictions on the degree of freedom in giving design qualities and functionalities relying on shape.
In addition, depending on the shape of a product, the shrinkage and deformation cause generation of cracks, unevenness in shape, and degradation in dimensional accuracy, and hence sometimes become a source for lowering the process yield.
Furthermore, molded bodies being large in volume, thereby the setting efficiency gets worse, and the productivity cannot be said to be sufficiently satisfactory.
Accordingly, the object of the present invention is to provide the sanitary ware for which it is possible to accurately design the shape and dimension of a product after being subjected to firing while maintaining the mechanical strength required to sanitary ware, degradation of the process yield caused by shrinkage and deformation scarcely occurs, and the setting efficiency and productivity are improved as compared to the prior art.
DISCLOSURE OF THE INVENTION
The present invention provides, for the purpose of solving the above described problems, the sanitary ware, which is formed of a ceramic body with a glaze layer formed on the desired portions of the body, characterized in that the body is the one containing a crystal phase mainly composed of mullite and quartz, a glass phase mainly composed of SiO
2
and Al
2
O
3
, and a crystal phase comprising those minerals selected according to need from cristobalite, andalusite, sillimanite, kyanite, and corundum; the main components of the body are 50 to 65 wt % SiO
2
, 30 to 45 wt % Al
2
O
3
, 0.1 to 2 wt % alkali oxides, and 0.1 to 10 wt % divalent metal oxides, the divalent metal oxide component containing at least the CaO component; and the CaO component segregation portions where the CaO component is segregated are dispersed in the body.
Since the CaO component segregation portions where the CaO component is segregated are dispersed, it becomes possible to provide the sanitary ware for which the firing shrinkage is sufficiently small while maintaining the mechanical strength required to sanitary ware, so that it is possible to accurately design the shape and dimension of a product after being subjected to firing; and the degradation of the process yield caused by shrinkage and deformation scarcely occurs, and the setting efficiency and productivity are satisfactory.
The reason for the above description can be interpreted as follows. Since the CaO component segregation portions where the CaO component is segregated are dispersed, the shrinkage caused by sintering of the liquid phase is suppressed in the segregation portions, and hence the firing shrinkage is suppressed. Furthermore, owing to the presence of the CaO component segregation portions which portions are different in such mechanical properties as Young's modulus and the like, the crack deflection effect takes place, and consequently the mechanical strength can take a sufficient value.
In the preferred embodiments of the present invention, the above described crystal phase is dispersed in the above described glass phase, and the composition ratio of the glass phase to the body is smaller than 60 wt %.
By suppressing the glass phase ratio to be smaller than 60 wt %, the large shrinkage following the liquid phase sintering is suppressed, and accordingly the firing shrinkage can be suppressed to be 6% or below.
In the preferred embodiments of the present invention, the relationships between the abundance ratios of Ca to Na, K, and Mg (in weight ratios) in the CaO component segregation portion are made to satisfy all the relations, Ca>Na, Ca>K, and Ca>Mg.
Accordingly, the components in the CaO component segregation portion are largely different from the components in the glass phase, so that the effect due to the dispersion of the CaO component segregation portions is accentuated.
In the preferred embodiments of the present invention, the content of the CaO component in the body is made to be 1 wt % or above.
By making the content of the CaO component to be 1 wt % or above, an excellent ratio of the bulk specific gravity to the strength can be obtained. This is interpreted to be ascribable to the observation that when the CaO component is abundant, the shrinkage in the glass phase following the liquid phase sintering is suppressed to be small.
In the preferred embodiments of the present invention, the relationships between the CaO component and the other divalent metal oxide components in the above described body are made to satisfy the condition that in relation to 100 parts by weight of CaO, the other divalent metal oxides are 50 parts by weight or below.
Consequently, an excellent ratio of the bulk specific gravity to the strength can be obtained. This is interpreted to be ascribable to the observation that when the CaO component is abundant, the shrinkage in the glass phase following the liquid phase sintering is suppressed to be small.
In the preferred embodiments of the present invention, the content of quartz in the body is made to be 20 wt % or below.
Consequently, it becomes possible to suppress the excessive increase in the thermal expansion coefficient of the body, and hence the cracks are scarcely caused to occur in such products large in size and complex in structure as sanitary ware during the temperature decrease process in firing.
In the preferred embodiments of the present invention, when corundum is contained in the body, the content of corundum is made to be 20 wt % or below.
Since corundum has a high Young's modulus, by uniformly dispersing corundum, a large effect of improving the strength can be obtained.
When corundum is contained in the body, it is preferable to make the corundum content be 20 wt % or below. The specific gravity of corundum is larger than the other minerals and glass phase, and hence when the body contains more than 20 wt % of corundum, the specific gravity of the body becomes heavy, resulting in an increase in cost when processing the bodies.
The present invention provides the sanitary ware which can be produced by the method comprising the process for molding the body raw material, the process for applying glaze, according to need, onto the desired portions, and the process for firing at the temperatures 1100 to 1300° C., and which are characterized in that the body raw material contains a clay mineral, quartz, a raw material containing alkali metals, and a raw material containing divalent metals; the clay mineral is a mineral which contains at l
Ishikawa Hidemi
Kato Ryosuke
Koga Naoki
Yoshida Atsushi
Blackwell-Rudasill G.
Jones Deborah
Toto Ltd.
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