METHOD AND PROCESS FOR CREATING A COMPOSITE MATERIAL

Abstract

The present invention relates a molded composite material and a method and process for creating the composite material from either recycled low grade mixed glass cullet or new glass. The composite material including; crushed glass; one or more aluminium compounds selected from oxide and hydrate at combined 0.40%-0.78% weight per weight of the glass; oxides of silicon, boron, sodium, calcium and potassium at combined 1.27%-1.90% weight per weight of the glass; zirconium silicate at 0.48%-1.3% weight per weight of the glass; and optionally tin oxide at 0%-0.45% weight per weight of the glass. The composite of the present invention can be used for making tiles, bench tops, work surfaces or other similar types of building products. The use of low grade mixed glass can also help reduce the amount of used glass being dumped in landfill or used in other low value enterprises such as providing highway aggregate or landfill cover.

Claims

1. A molded composite material, comprising: a) crushed glass; b) one or more aluminium compounds selected from oxide and hydrate at combined 0.40%-0.78% weight per weight of the glass; c) oxides of silicon, boron, sodium, calcium and potassium aluminium at combined 1.27%-1.90% weight per weight of the glass; and d) zirconium silicate at 0.5%-1.3% weight per weight of the glass.

2. The molded composite material as claimed in claim 1, wherein the molded composite material is in the form of a tile.

3. The molded composite material as claimed in claim 2, wherein the molded composite material comprises: crushed glass (20 kg); alumina hydrate (120 g); tin oxide (60 g); zirconium silicate (140 g); Frit 3134-2 (180 g); Frit KMP4131 (150 g); and color stain (280 g).

4. A pre-firing mix for the molded composite material as claimed in claim 2, which comprises: crushed glass (20 kg); alumina hydrate (120 g); tin oxide (60 g); zirconium silicate (140 g); Frit 3134-2 (180 g); and Frit KMP4131 (150 g); color stain (280 g).

5. The molded composite material as claimed in claim 1, wherein the molded composite material is in the form of a bench top.

6. The molded composite material as claimed in claim 5, wherein the molded composite material comprises: crushed glass (20 kg); alumina hydrate (120 g); tin oxide (60 g); zirconium silicate (140 g); Frit 3134-2 (180 g); Frit KMP4131 (150 g); and color stain (280 g).

7. A pre-firing mix for the molded composite material as claimed in claim 5, which comprises: crushed glass (20 kg); alumina hydrate (120 g); tin oxide (60 g); zirconium silicate (140 g); Frit 3134-2 (180 g); Frit KMP4131 (150 g); and color stain (280 g).

8. A pre-firing mix for a molded composite material comprising: a) crushed glass; b) one or more aluminium compounds selected from oxide and hydrate at combined 0.40%-0.78% weight per weight of the glass; c) oxides of silicon, boron, sodium, calcium and potassium at combined 1.27%-1.90% weight per weight of the glass; and d) zirconium silicate at 0.5%-1.3% weight per weight of the glass;

9. A molded composite material, comprising: a) crushed cullet glass; b) one or more aluminium compounds selected from oxide and hydrate at combined 0.40%-0.78% weight per weight of the glass; c) oxides of silicon, boron, sodium, calcium and potassium aluminium at combined 1.27%-1.90% weight per weight of the glass; and d) zirconium silicate at 0.5%-1.3% weight per weight of the glass.

10. A molded composite material, comprising: a) crushed glass; b) one or more aluminium compounds selected from oxide and hydrate at combined 0.40%-0.78% weight per weight of the glass; c) oxides of silicon, boron, sodium, calcium and potassium aluminium at combined 1.27%-1.90% weight per weight of the glass; and d) zirconium silicate at 0.5%-1.3% weight per weight of the glass, wherein the composite comprises no liquid content.

11. A pre-firing mix for the molded composite material as claimed in claim 3, which comprises: crushed glass (20 kg); alumina hydrate (120 g); tin oxide (60 g); zirconium silicate (140 g); Frit 3134-2 (180 g); Frit KMP4131 (150 g); and color stain (280 g).

12. A pre-firing mix for the molded composite material as claimed in claim 6, which comprises: crushed glass (20 kg); alumina hydrate (120 g); tin oxide (60 g); zirconium silicate (140 g); Frit 3134-2 (180 g); Frit KMP4131 (150 g); and color stain (280 g).

13. The molded composite material of claim 1, further comprising tin oxide at up to 0.45% weight per weight of the glass.

14. The pre-firing mix for a molded composite material of claim 8, further comprising tin oxide at up to 0.45% weight per weight of the glass.

15. The molded composite material of claim 9, further comprising tin oxide at up to 0.45% weight per weight of the glass.

16. The molded composite material of claim 10, further comprising tin oxide at up to 0.45% weight per weight of the glass.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0118] Further aspects of the present invention will become apparent from the following description which is given by way of example only and with reference to the accompanying drawings in which:

[0119] FIG. 1 is a graph showing ramp and dwell times used in one preferred implementation of the method of the present invention for the formation of a composite tile;

[0120] FIG. 2 is a graph showing ramp and dwell times used in a second implementation of the method of the present invention for the formation of a composite benchtop. In this embodiment the ramp rates for heating and cooling are higher than in preferred implementations where the ramp rate for heating and cooling is approximately 20-30° C. per hour;

[0121] FIG. 3 is an isometric drawing showing one preferred embodiment of a mold for forming a planar block of composite material in accordance with the present invention;

[0122] FIG. 4 is an isometric drawing showing a second preferred embodiment of a mold with a lid for forming a planar block of composite material in accordance with the present invention; and

[0123] FIG. 5a-e show a pictorial representation of the various stages of operation of the mold depicted in FIG. 4.

BEST MODES FOR CARRYING OUT THE INVENTION

[0124] The present invention will now be described by way of example.

[0125] The preparatory stage of forming a composite material includes the design and construction of a suitable mold for formation of the final shape of the composite product. The complexity of such mold construction falls outside the scope of the present invention and therefore will be excluded from the discussion herein.

Example 1: High Quality Composite Tile

[0126] A pre-firing mix was formed by mixing together finely crushed glass (20 kg) with the following non-glass components: alumina hydrate (120 g); tin oxide (60 g); zirconium silicate (140 g); Frit 3134-2 (180 g); Frit KMP4131 (150 g); and colour stain (280 g).

[0127] The non-glass components had been passed through a #60 stainless steel sieve. The finely crushed glass was obtained from mixed glass cullet that had been passed through a #60 stainless steel sieve.

[0128] The mixture was evenly mixed together in a rotary tumble mixer before being evenly spread in a high temperature mold. The mold is made from a high temperature material and is formed in the shape of the tile to be formed and includes any surface pattern that is to be included on the tile. One or more similar molds and associated mixtures are located in a kiln at ambient room temperature.

[0129] The kiln temperature is raised from ambient temperature at a rate of 100° C. per hour to a temperature of 350° C., at which point the kiln is programmed to maintain substantially 350° C. for 20 minutes. The kiln temperature is then raised from 350° C. to 550° C. at a rate of 140° C. per hour, upon reaching 550° C. the kiln maintains temperature for 20 minutes. On completion of the hold period the kiln temperature is raised at a rate of 145° C. per hour to a temperature of 800° C., at which point the kiln maintains 800° C. for 20 minutes. The kiln temperature is then raised one final time at a rate of 130° C. per hour to a final temperature of 895° C., the kiln temperature is held at 895° C. for 7 minutes. Following the hold period, and the formation of the fired mix, the temperature of the kiln is allowed to fall in a number of stages at the kiln's natural rate of thermal loss.

[0130] It will be apparent to a person skilled in the art that the rate of cooling will vary greatly between different kilns. Furthermore, the rate of cooling of any material is proportional to the temperature differential between the material and the ambient surroundings, therefore the rate of cooling will typically be non-linear, the rate of cooling slowing greatly as the temperature becomes close to the ambient temperature. For the purposes of the present example, and simplicity of explanation, the natural rate of cooling of the kiln has been arbitrarily selected as being linear and at a rate of 200° C. per hour. The first cooling stage is from 895° C. to 770° C., the temperature is held at 770° C. for 60 minutes before it is allowed to fall to 675° C. before it is once again held for 60 minutes before being allowed to cool to 590° C. and once more held for 60 minutes. The kiln is then allowed to self cool to ambient temperature.

[0131] Once ambient temperature is reached the molds are removed from the kiln and the composite tiles can be removed in their final form.

Example 2: Benchtop Unit

[0132] A pre-firing mix was formed by mixing together finely crushed glass (20 kg) with the following non-glass components: alumina hydrate (120 g); tin oxide (60 g); zirconium silicate (140 g); Frit 3134-2 (180 g); Frit KMP4131 (150 g); and colour stain (280 g).

[0133] The non-glass components had been passed through a #60 stainless steel sieve. The finely crushed glass was obtained from mixed glass cullet that had been passed through a #60 stainless steel sieve.

[0134] The mixture was evenly mixed together in a rotary tumble mixer before being evenly spread in a high temperature mold. The mold is made from a high temperature material and is formed in the size and shape of the benchtop to be formed and includes any surface pattern that is to be included on the benchtop. For example the benchtop is formed as a substantially homogeneous planar block corresponding to the desired shape and thickness properties of the final product. One or more similar molds and associated mixtures may be located in a kiln at ambient room temperature.

[0135] While thinner materials, such as composite tiles, can be heated and cooled at faster rates (such as 145° C. per hour), thicker materials such as planar blocks (exemplified by a benchtop unit) should preferably be heated and cooled at slower rates. Preferably these slower rates provide a temperature change of approximately 20-30° C. per hour. These slower rates allow the increased volume of glass to heat up more uniformly.

[0136] The kiln temperature is raised from ambient temperature at a rate of approximately 20-30° C. per hour to a temperature of 350° C., at which point the kiln is programmed to maintain substantially 350° C. for 30 minutes. The kiln temperature is then raised from 350° C. to 550° C. at a rate of approximately 20-30° C. per hour, upon reaching 550° C. the kiln maintains temperature for 30 minutes. On completion of the hold period the kiln temperature is raised at a rate of approximately 20-30° C. per hour to a temperature of 800° C., at which point the kiln maintains 800° C. for 30 minutes. The kiln temperature is then raised one final time at a rate of approximately 20-30° C. per hour to a final temperature of 925° C., the kiln temperature is held at 925° C. for 30 minutes. Following the hold period, and the formation of the fired mix, the temperature of the kiln is allowed to fall in a number of stages at the kiln's natural rate of thermal loss, and/or preferably at a cooling rate of approximately 20-30° C. per hour.

[0137] It will be apparent to a person skilled in the art that the kiln's natural rate of cooling will vary greatly between different kilns. Furthermore, the rate of cooling of any material is proportional to the temperature differential between the material and the ambient surroundings, therefore the rate of cooling will typically be non-linear, the rate of cooling slowing greatly as the temperature becomes close to the ambient temperature. For the purposes of the present example, and simplicity of explanation, in one embodiment the natural rate of cooling of the kiln has been arbitrarily selected as being linear and at a rate of 200° C. per hour. In one preferred embodiment, the cooling rate of the kiln is controlled to a rate of approximately 20-30° C. per hour.

[0138] The first cooling stage is from 925° C. to 770° C., the temperature is held at 770° C. for 60 minutes before it is allowed to fall to 675° C. before it is once again held for 60 minutes before being allowed to cool to 590° C. and once more held for 60 minutes. The kiln is then allowed to self cool to ambient temperature.

[0139] Once ambient temperature is reached the molds are removed from the kiln and the composite planar block can be removed and located in a further mold. The further mold (not shown) comprises a support upon which any area of the planar block which is intended to be flat is supported and a basin structure which is forms a void beneath at least a portion of the composite planar block.

[0140] FIG. 3 shows one preferred embodiment of a mold for producing tiles, as generally indicated by arrow 100. The mold comprises a rectangular plate 101 which has a recessed central portion 102. The central portion is larger in size than the size of the tile that is to be produced. The reason for this is that as the pre-firing mix fuses into the composite material the volume of the product typically shrinks, which can result in an irregular shape and therefore sufficient excess is required so that the edges of final product can be ground square.

[0141] FIG. 4 shows a further preferred embodiment of a mold for producing tiles, as generally indicated by arrow 200. The mold of FIG. 4 includes a rectangular plate 201 which has a recessed central portion 202, the mold also includes a lid portion 203 which fittingly engages with the central portion 202. As the pre-firing mix fuses into the composite material the volume of the product typically shrinks. Advantageously the weight of the lid portion 203 presses down on the mixture such that the mixture conforms to the shape of the recessed central portion 202. By using a lid portion 203 the tile produced requires no further finishing in the form of grinding the edges.

[0142] The process of the lid portion 203 maintaining the conformance of the composite product to the recessed central portion 202 by maintaining downward pressure of the mixture is illustrated in FIGS. 5a-5e, whereby the lid portion is shown moving further into the recessed central portion 202 as the composite mixture fuses and reduces in volume.

[0143] Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope thereof.