DE2435502A1 - METHOD OF MANUFACTURING TILES - Google Patents

Description

Method of making tiles

Tiles, for example for floors and walls, mainly exist made of clay, talc, chamotte and silica minerals, which are used for tile mixtures in various combinations and Mixtures can be used. Unglazed tiles are fine-pored and normally have a water absorption of more than 4% by weight, generally from 6 to 10% by weight, although certain types of so-called glass-like tiles have less water absorption than 4 wt.% May have. Most wall and floor tiles have a waterproof glaze on the front glazed, which adheres firmly to the tile material, while the reverse side is in contact with the floor or wall is usually unglazed.

The invention has set itself the task of providing a tile with great uniformity with regard to the external dimensions and a much improved wear resistance in comparison

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with previously available. To propose tiles, for these excellent properties presumably those in the manufacture materials used are responsible.

The invention accordingly relates to a method of production a tile particularly suitable for floors, characterized by the following process steps:

a) Injection of a mixture of finely divided solids and water containing 4–6% by weight vermiculite, 25 to 40% by weight clay, 0.01 to 8% by weight flux and 10 to 20% by weight water contains, to a tile with a density of 1.12 to 1.36 g / cm,

b) applying a glaze and

c) Firing the glazed and pressed mixture at a temperature of 1095 to 12O5 ° C.

The product made by the process of the invention has high compressive strength, wear resistance and linear shrinkage. The density of the fired product is significantly lower than that of comparable commercially available fired products. Typical, through the application of the invention Properties of the tile that can be achieved by the process are: A density of the fired product between 1.44 and 1.92 g / cm, a linear shrinkage on burning of less

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than 10% down to 4% and a wear index after Taber of over 20,000.

The solids of the mixture to be pressed are in finely divided form Form before, that is usually as a powder. A suitable powder and a method for its preparation is described in U.S. Patent 3,778,281. This press powder contains vermiculite, clay and a sodium metaphosphate borax flux. A floor tile can be made from a pressed powder with specifically these components according to the method according to the invention getting produced.

The vermiculite to be used is preferably an expanded vermiculite having a density of 0.080 to 0.176 g / cm. the Vermiculites are numbered 1-5; according to the invention are preferably vermiculite No. 4 or 5 with a small Grain size used, although other vermiculites are also useful.

Bentonite is preferably used as the clay; other tones can also be used. Leafy clays are preferred to the product to give high strength. Typical useful clays are Precambrian Shale, Alluvial Clay, South Carolina Kaolin, binding clay, especially Tennessee binding clay, carbon clay, especially Alabama carbon clay and attupulgite.

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The presence of small amounts of other components in the starting mixture, for example up to 8% wollastonite fibers, is possible.

The flux is a substance that will melt the vermiculite and clay at a temperature below the temperature at which they would melt without the addition of flux. A preferred flux consists primarily of borax and sodium metaphosphate. The borax (Na ^ B ₄ O ₇ .1OH "O) and the Natrxununetaphosphat /" (NaPO-) J cause the vermiculite and clay to melt together at a temperature as low as 700 ° C and form a product with a vermiculite matrix, which is held together by a continuous phase This flux is used in an amount of 0.01 to 8% by weight, preferably 0.01 to 4% by weight, based on the end product.

The starting powder is preferably produced by dry mixing the ingredients. This mixture is then 10 to 20% by weight of water are mixed and the resulting mixture is poured into a suitable tile-shaped mold. The concentration the press mix before pressing is about 0.16 to 0.24 g / cm. The tile is made by pressing the molding powder to a density of 1.12 to 1.36 g / cm.

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The pressed ingredients are then coated with a glaze using conventional glazing techniques. A preferred one Glaze contains boron oxide, silicon oxide, aluminum oxide and calcium oxide as main components. As minor ingredients the oxides of sodium, potassium, zinc, iron, magnesium and titanium are used. An example of a preferred glaze is a glaze with the following components:

Components wt.%

Boron oxide 20 to 35

Silica 35 to 55

Alumina, 5 to 20

Calcium oxide 5 to 15

Sodium Oxide 1 to 3

Potassium oxide 0.5 to 2

Zinc oxide 1 to 8

Iron oxide 0.01 to 0.4

Lithium oxide 0.01 to 0.3

Magnesium oxide 0.01 to 0.3

Titanium dioxide 0.01 to 0.2

When the pressed vermiculite tile body is coated with this glaze and then fired, the ingredients melt the glaze together and form the glaze coating. The preferred one Firing temperature is 1150 ° C and the preferred firing time is 0.5 to 4 hours, better still 2 to 4 hours.

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A special, particularly preferred method according to the invention is characterized by:

1) Prepare a mixture that consists of approximately 50% by weight vermimiculite No. 4, about 34% by weight bentonite, about 2% by weight of a borax sodium phosphate flux, and about 14% by weight Water exists.

2) Compressing the resulting powder to a density of about 1.12 to 1.36 g / cm ³ .

3) Applying a glaze, mainly made of boron oxide, Consists of silica, alumina and calcium oxide.

4) Burning for about 0.5 to 4 hours at a temperature of about 1150 C.

5) cooling and removing the tile product from the kiln.

The invention is illustrated by the following examples ".

Example 1 (comparison)

A pressed powder was produced by adding 50.5% by weight of vermiculite No. 4, 33.8% by weight of bentonite, 1% by weight of borax and 0.7% by weight of sodium metaphosphate were mixed with 14% by weight of water. the Mixture was placed in a suitable tile mold and pressed to a density of 0.96 g / cm. It became a glaze of the following composition applied:

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- π -

Components Parts by weight approximate

Boric acid 100

Wollastenite (a) 50

Feldspar (b). 50

Jackson binding clay 75

CMC - 7 MS (c) 2.5

Zinc oxide 5.0

Water '300

(a) A mineral _{composed mainly of CaO.SiO 0.}

(b) A mineral _{composed mainly of K 2} O-Al ₃ O ₃ -O SiO _2.

(c) A carboxymethyl cellulose / gum product.

Three samples were fired at 1065, 1120 and 1175 ° C, respectively. That Product was designated as tile A.

Example 2

A second tile was made from the same components and using the same mixing technique as in Example 1. This time, however, the press powder was pressed to a density of 1.12 g / cm. A glaze according to Example 1 was obtained applied. Two samples were fired at 1120 and 1175 C respectively. This tile was designated as tile B.

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Example 3

A molding powder having the same composition as in Example 1 was prepared and this in the same manner pressed to a density of 1.36 g / cm. It became a glaze applied according to Example 1. Two samples were taken at 1120 or 1175 ° C fired. This tile was referred to as tile C.

Example 4

The tiles produced according to Examples 1 to 3 were compared with a commercially available tile that had been fired at 1150 ° C. The results are shown in the following table,

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tile

Tabel

Dense density

Burning bending pressure wear and tear before after the linear 'water temperature strength strength index after burning burning shrinkage ^{absorption (0} C) (kg / cm2) (kg / cm ² ) Taber (g / cm ³ ) (g / cm ³ ) (%) (%)

A. 1065 91 95 3,930 0.96 1.19 B. 1120 146 105 7,460 1.12 1.41 cn
O C. 1120 194 214 23,780 1, 36 1.54 9807 / B.
C. 1175
1175 235
309 548
465 23,160
46,320 1.12
1, 36 1.77
1, 93 O
OO

CD

8.5
5.2
4.2
7.7
7.2

48.2

33.6

25.4

Comparison with a commercial product

1150

3.810

1.78

2.34

15.1

7.4

ir '^

cn cn ο M

Example 5

This example shows that a small proportion of wollastonite fibers may be included, although the properties of the tile are not as good as those of some tiles according to Example 1 to 4. The molding powder was produced by adding 60% vermiculite, 27% bentonite, 8% wollastonite fibers and 5% of a solid flux according to US Pat. No. 3,778,281 were mixed with water in a ratio of 100 parts by weight of solid to 16 parts by weight of water. This material

3
with a density of 0.19 g / cm was then pressed to a density of 0.96 g / cm, glazed according to Example 1 and then fired at 1150 ° C. for three hours.

The physical properties of the fired tile were as follows:

Flexural Strength (kg / cm) 141

Compressive strength (kg / cm ² ) 193 Taber wear index 10,000

Density (g / cm ³ ) '1.76

linear shrinkage (%) 7.2

Water absorption (%), 6.0

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These values show that the tile produced by the process according to the invention has a significantly improved Taber index compared to the commercial product. It also has a much lower density after firing and a linear shrinkage that is approximately half that of the commercial product.

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Claims (5)

Expectations Μ. ' Method for producing a tile, characterized by the following process steps: (a) pressing a mixture of finely divided solids and water, the 40 to 60 wt% vermiculite, 25 to 40 wt% clay, 0.01 to 8 wt.% Flux and 10 to 20 wt.% Water, to a tile with a density of 1.12 to 1.36 g / cm, (b) applying a glaze and (c) firing the glazed and pressed mixture at 109t to 1205 C. 2. The method according to claim 1, characterized in that an expanded vermiculite is used as the vermiculite a density of 0.080 to 0.176 g / cm - is used. 3. The method according to claim 2, characterized in that a vermiculite No. 4 or 5 is used. 4. The method according to claim 1 to 3, characterized. That one uses egg run clay leaf structure. 5. The method naoh claim 4, characterized in that Bentonite is used as clay. 5098 07/0819 - 13 - 6. The method according to claim 1 to 5, characterized in that one of sodium borate and sodium metaphosphate is used as the flux composite flux used. 7. The method according to claim 1 to 6, characterized in that that a mixture is used which still contains up to 8% by weight of wollastonxt fibers. 8. The method according to claim 1 to 7, characterized in that the main components of the glaze are boron oxide, silicon oxide and calcium oxide are used. 9. The method according to claim 1, characterized in that the proportion of the flux is 0.1 to 8% by weight, that of the vermiculite, the clay, the flux and the water be mixed into a powder that this resulting powder is pressed to a density of 1.12 to 1.36 g / cm is that a glaze, the main components of which are boron oxide, silicon oxide, aluminum oxide and calcium oxide is applied and that the glazed and pressed mixture for 2 to 4 hours at a temperature of 1095 to 1205 C is burned. ue: ka: kö 5 0 9 8 0 7/0819