Ceramic tile and glaze for use thereon

Details Ceramic tile and glaze for use thereon Ceramic tile and glaze for use thereon

1998-11-12

2001-01-16

Speer, Timothy M. (Department: 1775)

Stock material or miscellaneous articles

Composite

Of quartz or glass

C428S427000, C428S428000, C428S432000, C501S014000, C501S021000, C501S023000, C501S026000

Reexamination Certificate

active

06174608

ABSTRACT:

FIELD OF INVENTION
The present invention concerns a ceramic architectural tile and a glaze composition for use in forming such tile.
BACKGROUND
The prior art provides various methods for forming ceramic tiles for architectural applications, and it also provides various glaze compositions which are used to produce the top surface or wear surface of the tile.
Generally, the formation of a ceramic tile involves the steps of forming a raw tile or an unfired ceramic body. Such ceramic bodies are formed from batches of natural or synthetic raw materials such as clay, kaolin, feldspar, wollastonite, talc, calcium carbonate, dolomite, calcined kaolin, oxides such as alumina, silica, corundum and mixtures of the foregoing. Binders and other additives may also be employed to increase the raw mechanical strength of the body.
Once formed, the bodies are fired to form a biscuit that is hard, tough and brittle. In many instances, a glaze composition is applied to the biscuit and given a further firing (double firing) in order to vitrify or sinter the glaze, depending upon the degree of firing. Upon firing the glaze develops a vitreous, transparent or opaque surface that can be glossy or dull (matte), or somewhere in between glossy and dull. Glazes generally comprise one or more glass frits, fillers, pigments and other additives.
In addition to double firing, it is well-known in the prior art to produce tiles by a single fire approach. In the single fire approach, the glaze is applied to the raw ceramic body, and the body and the glaze are then subjected to a single firing operation in order to produce the finished tile.
SUMMARY OF THE INVENTION
The present invention provides a new and improved ceramic architectural tile and a new and improved glaze composition for use thereon. The glaze composition of the present invention provides a glaze finish that displays excellent abrasion resistance. More particularly, the glaze displays a degree of abrasion resistance that exceeds all the test criteria of ISO 10545-7 (1993). The glaze composition of the present invention is also capable of producing a smooth finish that is semi-transparent in appearance.
A ceramic tile made in accordance with the present invention comprises a fired ceramic body portion and a glaze coating on at least a portion of the surface of the ceramic body portion. The glaze coating is formed by firing a composition comprising a glass composition, an expansion modifier and a spodumene crystallization promotor, In a preferred embodiment the glass composition comprises from about 40% to about 82% by weight SiO
2
, from about 5% to about 32% by weight Al
2
O
3
, up to about 15% by weight CaO, up to about 20% by weight BaO, up to about 10% by weight MgO, up to about 15% by weight ZnO, up to about 4% by weight K
2
O, up to about 4% by weight Na
2
O, from about 5% to about 13% by weight Li
2
O, up to about 5% ZrO
2
, up to about 5% by weight TiO
2
, up to about 3% by weight P
2
O
5
and up to about 5% by weight B
2
O
3
. The glass composition may also include up to 10% by weight PbO. However, the use of lead oxide is not required.
The foregoing and other features of the invention are hereinafter more fully described and particularly pointed out in the claims, the following description setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principles of the present invention may be employed.
DETAILED DESCRIPTION
The green or unfired ceramic bodies that form the tiles of the present invention may be formed using conventional technologies and methods. Both single fire and multiple fire techniques may be employed.
In the case of the single fire approach, the raw tile is not previously fired, the application of the glaze composition being made on the green or unfired ceramic body. After application of the glaze composition, the coated tile is subjected to a kiln or similar heating device and the body and glaze are then simultaneously fired. In the case of the double fire approach, the glaze composition is applied to a previously fired body, and then the glaze and body are fired, the body thus being subjected to two firing operations.
The glaze composition of the present invention may be applied using any one of a variety of conventional application techniques and also in any one of various forms. For example, the glaze composition may be applied wet or dry. Such application techniques as disk and bell applications, spraying, screen printing, brushing and electrostatic application may be employed.
The glaze composition of the present invention includes a glass composition, an expansion modifier and a spodumene crystallization material or promoter.
The glass composition is formed from one or more glass frits using conventional glass melting techniques. Set forth below is the composition for the glass composition.
Component
Range (Wt %)
Preferred Range (Wt %)
SiO
2
40-82
57-82
Al
2
O
3
 5-32
 5-24
CaO
 0-15
 0-10
BaO
 0-20
 0-18
MgO
 0-10
0-5
ZnO
 0-15
 0-12
K
2
O
0-4
0-2
Na
2
O
0-4
0-1
Li
2
O
 5-13
 6-13
ZrO
2
0-5
0-4
TiO
2
0-5
0-4
P
2
O
5
0-3
0-2
B
2
O
3
0-5
0-4
PbO
 0-20
 0-10
The glass frits of the present invention can be melted in a conventional manner including through the use of a continuous melter, discontinuous melters such as rotary melters and refractory crucibles at temperatures of from about 1400°-1600° C. The glass melt may be handled by suitable conventional means though typically it is quenched by steel rolls into flake or frit, using techniques well-known to those skilled in the art.
Various expansion modifiers may be included in the glaze composition in order to help ensure a good expansion match as between the resultant glaze coating and the tile body. Examples of such modifiers include quartz, zirconia, spinels and mixtures thereof Additionally, it will be appreciated that depending upon the specific application, an intermediate or engobe layer may be employed between the tile body and the layer of glaze.
Upon firing, the glaze composition displays a beta spodumene crystal structure. Preferably, the glaze displays at least about 30% by volume beta spodumene. Preferably, the beta spodumene does not exceed about 70% by volume of the structure of the fired glaze. It will be appreciated that in addition to beta spodumene, other phases such as virgilite may form. In order to ensure such beta spodumene structure, the glaze composition includes a material that promotes the formation of beta spodumene during firing. Examples of spodumene crystallization promoters suitable for use in the present invention include materials such as, for example, spodumene, eucryptite, alumina, amblygonite, calcium phosphate, petalite, and mixtures of the foregoing.
The glass components, the expansion modifiers and the spodumene crystallization promoters define or form the solids portion of the glaze composition. In addition to the “solids portion,” it will be appreciated that the glaze composition may include other additives and fillers such as vehicles, flocculants, antifoaming agents, deflocculants, binders, wetting agents, antifoaming agents, dyes, pigments, tin oxide, zirconium oxide, silicates to opacify the glaze, zinc oxide, wollastonite, feldspar, dolomite and magnesium carbonate may be employed.
Generally, the solids portion of the glaze composition comprises from about 70% to about 99% by weight glass component, from about 0% to about 40% by weight expansion modifier, and from about 0.5% to about 50% by weight spodumene crystallization promoter.
The glaze composition is made according to the following technique. The glass frit(s), in flake or granular form, expansion modifier(s), spodumene promoter(s) and other additives are ball milled with water (finely milled to an average size of about 10-15 microns). The resulting slip, which comprises generally from about 30% to about 50% water, is then in condition for application upon a green ceramic body. Of course, it will be apprec

Affiliated with

Also associated with

Rating

Ceramic tile and glaze for use thereon does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Ceramic tile and glaze for use thereon, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ceramic tile and glaze for use thereon will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2479133