AU2020217435A1

AU2020217435A1 - Composite slab comprising recycled glass

Info

Publication number: AU2020217435A1
Application number: AU2020217435A
Authority: AU
Inventors: Robert Thompson; Roshni Thompson
Original assignee: Betta Stone Pty Ltd
Current assignee: Betta Stone Pty Ltd
Priority date: 2019-08-14
Filing date: 2020-08-14
Publication date: 2021-03-04
Also published as: AU2024100012A4

Abstract

A composite slab comprising recycled glass and a process of manufacturing the same are described herein. In some embodiments or examples, the composite slab comprises a) about 65% to about 95% (w/w) of milled recycled glass; and b) about 5% to about 35% (w/w) of a cured polyester resin, and can be prepared by curing a mixture of milled recycle glass and a polyester resin in a die to form the composite slab under a suitable pressure and temperature.

Description

COMPOSITE SLAB COMPRISING RECYCLED GLASS

CROSS-REFERENCE The present application claims priority from Australian Provisional Patent Application No. 2019902937 filed on 14 August 2019, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD The present invention relates to composite slabs comprising recycled glass. In particular, the present invention relates to recycled glass bench-tops and their methods of manufacture.

BACKGROUND Glass waste has created enormous challenges for the waste disposal and glass recycling industries. For example, recycling of waste glass for many industries necessitates purification of the glass and/or extensive processing for its subsequent re-use. Nevertheless, due to the costs of recycling and disposing of waste glass, much of the waste glass is still committed to undesirable landfill sites. There is therefore a need for new applications of waste glass that can alleviate much of the waste disposal problems currently associated with waste glass. Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present disclosure as it existed before the priority date of each of the appended claims. Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps

SUMMARY The present inventors have developed a method of preparing a composite slab material made from recycled glass which can be used in the building industry. The use of recycled glass to prepare the composite slabs of the present invention presents green alternative to current waste glass treatment and disposal processes used by industry. The present disclosure is directed to a composite slab comprises milled recycled glass. The composite slab may comprise about 65% to about 95% (w/w) of milled recycled glass. The milled recycled glass may have an average particle size. The milled recycled glass may be of micron size (e.g. less than 1 mm). The milled recycled glass may have an average particle size of about 0.01 pm to about 100 pm. The composite slab comprises a cured resin. The composite slab may comprise a cured polyester resin. The cured polyester resin may be a cured thermoset polyester resin. The composite slab may comprise about 5% to about 35% (w/w) of a cured polyester resin. The composite slab may comprise less than about 1% crystalline silica, for example may be substantially free of crystalline silica. The milled recycled glass and cured polyester resin are described herein. In one aspect, there is provided a composite slab comprising: a) about 65% to about 95% (w/w) of milled recycled glass; and b) about 5% to about 35% (w/w) of a cured polyester resin. In one aspect, there is provided a composite slab consisting of: a) about 65% to about 95% (w/w) of milled recycled glass; b) about 5% to about 35% (w/w) of a cured polyester resin; c) optionally 0% to about 1% crystalline silica; and c) optionally 0% to about 10% of one or more non-crystalline additives selected from a wetting agent, a dye, a pigment, and a filler. In one aspect, there is provided a composite slab comprising a cured reaction product of: a) about 65% to about 95% (w/w) of milled recycled glass; and b) about 5% to about 35% (w/w) of a polyester resin. In one aspect, there is provided a composite slab comprising: a) about 65% to about 95% (w/w) of milled recycled glass; and b) about 5% to about 35% (w/w) of a cured polyester resin, wherein the average particle size of the milled recycled glass is about 0.01 pm to about 100 pm. In a related aspect, there is provided a composite slab consisting of: a) about 65% to about 95% (w/w) of milled recycled glass; b) about 5% to about 35% (w/w) of a cured polyester resin; c) optionally 0% to about 1% crystalline silica; and c) optionally 0% to about 10% of one or more non-crystalline additives selected from a wetting agent, a dye, a pigment, and a filler, wherein the average particle size of the milled recycled glass is about 0.01 pm to about 100 pm. In another related aspect, there is provided a composite slab comprising a cured reaction product of: a) about 65% to about 95% (w/w) of milled recycled glass; and b) about 5% to about 35% (w/w) of a polyester resin, wherein the average particle size of the milled recycled glass is about 0.01 pm to about 100 pm. In one embodiment, the milled recycled glass is uniformly dispersed throughout the slab. In another embodiment, the composite slab is a bench-top. In one embodiment, the milled recycled glass is of micron size (e.g. less than 1 mm). In one embodiment, the average particle size of the milled recycled glass is about 0.1 pm to about 5 pm. In one embodiment, the average particle size of the milled recycled glass is about 0.1 pm to about 1 pm. In one embodiment, the composite slab comprises about 80% to about 90% (w/w) milled recycled glass. In one embodiment, the composite slab comprises about 10% to about 20% (w/w) polyester resin. In one embodiment, the composite slab further comprises one or more non crystalline additives selected from a wetting agent, a dye, a pigment, and a filler. In a further embodiment, the composite slab consists of about 80% to about 90% (w/w) milled recycled glass, about 10% to about 20% (w/w) polyester resin, optionally about 0% to about 1% crystalline silica; and optionally 0% to about 10% of one or more non-crystalline additives selected from a wetting agent, a dye, a pigment, and a filler. In one embodiment, the ratio of milled recycled glass to polyester resin is about 1:1 to about 20:1. In a further embodiment, the ratio of milled recycled glass to polymeric resin is about 4:1 to about 10:1. In one embodiment, wherein the composite slab comprises less than about 1% (w/w) crystalline silica. The present inventors have carefully developed a process of preparing the recycled glass composite slabs that are substantially free of crystalline silica free (i.e. less than 1% (w/w)). In one embodiment, the porosity of the composite slab is less than about 0.01. The present disclosure is also directed to a process for preparing a composite slab. The process comprises curing a mixture of milled recycled glass and a polyester resin to form a composite slab. The curing may be at a suitable temperature and/or pressure. The curing may be at a temperature of about 50°C to about 300°C.. The curing may be at a pressure of about 200 tonnes/m 2 to about 700 tonnes/m 2 . The curing time may be about 20 minutes to 120 minutes. Other suitable temperatures, times and pressures are described here. The pressure and/or temperature may be applied by a platen press, for example a heated platen press. In one aspect, there is provided a process for preparing a composite slab, comprising the step of: a) curing a mixture of milled recycled glass and a polyester resin to form a composite slab, wherein the curing is at a temperature of about 50°C to about 300°C and at a pressure of about 200 tonnes/m 2 to about 700 tonnes/m 2 .

In one embodiment , the process further comprises the step of: al) mixing the milled recycled glass and polyester resin to form a uniform mixture of milled recycled glass resin prior to the curing at step a). The mixing may be done in a paddle mixer. In one embodiment, the process further comprises adding an initiator to the milled recycled glass resin mixture. In one embodiment, the initiator is a peroxide. In one embodiment, the milled recycled glass mixture at step al) is mixed for about 5 minutes to about 30 minutes prior to the curing at step a). In one embodiment, a release agent is applied to the surface of the die prior to the curing at step a). In one embodiment, the curing is at a temperature of about 70°C and at a 2 pressure of about 400 tonnes/m .

In one embodiment, the curing is for a period of time of about 20 minutes to about 120 minutes. In one embodiment, the curing is for a period of time of less than 120 minutes, for example about 60 minutes.

In one embodiment, the curing is at a temperature of about 70°C, and at a pressure of about 400 tonnes/m 2, and for a period of time of about 60 minutes. In one embodiment, the curing is at a temperature of about 50°C to about 300°C and at a pressure of about 200 tonnes to about 700 tonnes. In one embodiment, the curing is at a temperature of about 50°C to about 300°C and at a pressure of about 300 tonnes to about 600 tonnes. In one embodiment, the curing is at a temperature of about 60°C to about 100°C and at a pressure of about 300 tonnes to about 600 tonnes. In one embodiment, the curing is for a period of time of about 20 minutes to about 120 minutes. In one embodiment, the curing is for a period of time of less than 120 minutes, for example about 60 minutes. In one embodiment, the curing is at a temperature of about 50°C to about 300°C, and at a pressure of about 200 tonnes to about 700 tonnes, and for a period of time of about 20 minutes to 120 minutes. In one embodiment, the curing is at a temperature of about 50°C to about 300°C and at a pressure of about 300 tonnes to about 600 tonnes, and for a period of time of about 20 minutes to 120 minutes. In one embodiment, the curing is at a temperature of about 60°C to about 100°C and at a pressure of about 300 tonnes to about 600 tonnes, and for a period of time of about 20 minutes to 120 minutes. In one embodiment, the curing pressure and temperature is provided by a platen press, for example a heated platen press. In one embodiment, the mixture comprises about 65% to about 95% (w/w) milled recycled glass. In a further embodiment, the mixture comprises about 80% to about 90% (w/w) milled recycled glass. In one embodiment, the mixture comprises about 5% to about 35% (w/w) polyester resin. In one embodiment, the milled recycled glass in the mixture is of micron size (e.g. less than 1 mm). In one embodiment, the average particle size of the milled recycled glass in the mixture is about 0.01 pm to about 100 pm. In a further embodiment, the average particle size of the milled recycled glass in the mixture is about 0.1 pm to about 5 pm, preferably about 0.1 pm to about 1 pm. In one embodiment, the ratio of milled recycled glass to polyester resin is about 1:1 to about 20:1. In a further embodiment, the ratio of milled recycled glass to polyester is about 4:1 to about 10:1.

In one embodiment, the mixture at step a) or al) further comprises one or more non-crystalline additives selected from a wetting agent, a dye, a pigment, and a filler. In one embodiment, the method provides a composite slab comprising less than about 1% crystalline silica. In one embodiment, the process provides a composite slab having a porosity ofless than about0.01. The embodiments described herein in relation to the composite slab also equally apply to the process steps for preparing the composite slab described herein. In a related aspect or embodiment, there is provided a composite slab comprising: a) about 65% to about 95% (w/w) of milled recycled glass; and b) about 5% to about 35% (w/w) of a cured thermoset polyester resin, obtained or obtainable by the process described above. In a related aspect or embodiment, there is provided a composite slab comprising: a) about 65% to about 95% (w/w) of milled recycled glass; and b) about 5% to about 35% (w/w) of a cured polyester resin, obtained or obtainable by the process comprising a) curing a mixture of milled recycled glass and a thermoset polyester resin in a die to form the composite slab, wherein the curing is at a temperature of about 50°C to about 300°C and at a pressure ofabout200 tonnes toabout700 tonnes. In one embodiment, the average particle size of the milled recycled glass is about 0.01 pm to about 100 pm. In one embodiment, the polyester resin is a thermoset polyester resin. In one embodiment, the curing is at a temperature of about 50°C to about 300°C and at a pressure of about 200 tonnes to about 700 tonnes. In one embodiment, the curing is at a temperature of about 50°C to about 300°C and at a pressure of about 300 tonnes to about 600 tonnes. In one embodiment, the curing is at a temperature of about 60°C to about 100°C and at a pressure of about 300 tonnes to about 600 tonnes. In one embodiment, the curing is for a period of time of about 20 minutes to about 120 minutes. In one embodiment, the curing is for a period of time of less than 120 minutes, for example about 60 minutes.

In one embodiment, the curing is at a temperature of about 50°C to about 300°C, and at a pressure of about 200 tonnes to about 700 tonnes, and for a period of time of about 20 minutes to 120 minutes. In one embodiment, the curing is at a temperature of about 50°C to about 300°C and at a pressure of about 300 tonnes to about 600 tonnes, and for a period of time of about 20 minutes to 120 minutes. In one embodiment, the curing is at a temperature of about 60°C to about 100°C and at a pressure of about 300 tonnes to about 600 tonnes, and for a period of time of about 20 minutes to 120 minutes. In one embodiment, the curing pressure and temperature is provided by a platen press, for example a heated platen press. The embodiments described herein in relation to the composite slab and the process also equally apply to the composite slab obtained or obtainable by the process described herein. In some embodiments or aspects, there is provided a platen press configured to cure a mixture of milled recycled glass and a polyester resin in a die to form the composite slab, wherein the composite slab comprises: a) about 65% to about 95% (w/w) of milled recycled glass; and b) about 5% to about 35% (w/w) of a cured polyester resin In one embodiment, the average particle size of the milled recycled glass is about 0.01 pm to about 100 pm. In one embodiment, the polyester resin is a thermoset polyester resin. In one embodiment, the platen press is configured to provide a curing temperature and pressure. In one embodiment, the platen press is configured to provide a curing temperature of about 50°C to about 300°C and a pressure of about 200 tonnes to about 700 tonnes. In one embodiment, the platen press is configured to provide a curing temperature of about 50°C to about 300°C and a pressure of about 300 tonnes to about 600 tonnes. In one embodiment, the platen press is configured to provide a curing temperature of about 60°C to about 100°C and a pressure of about 200 tonnes to about 700 tonnes. In one embodiment, the platen press is configured to provide a temperature of about 60°C to about 100°C and a pressure of about 300 tonnes to about 600 tonnes. In one embodiment, the platen press is configured to provide a curing time of about 20 minutes to about 120 minutes. In one embodiment, the platen press is configured to provide a curing time of less than 120 minutes, for example about 60 minutes. In one embodiment, the platen press is configured to provide a curing time temperature of about 50°C to about 300°C, and curing pressure of about 200 tonnes to about 700 tonnes, and a curing period of time of about 20 minutes to 120 minutes. In one embodiment, the platen press is configured to provide a curing time temperature of about 50°C to about 300°C and curing a pressure of about 300 tonnes to about 600 tonnes, and a curing time of about 20 minutes to 120 minutes. In one embodiment, the platen press is configured to provide a curing time temperature of about 60°C to about 100°C and a curing pressure of about 300 tonnes to about 600 tonnes, and a curing time of about 20 minutes to 120 minutes. The embodiments described herein in relation to the composite slab and process also equally apply to the platen press configured to prepare the composite slab described herein. Any embodiment herein shall be taken to apply mutatis mutandis to any other embodiment unless specifically stated otherwise. The present invention is not to be limited in scope by the specific embodiments described herein, which are intended for the purpose of exemplification only. Functionally-equivalent products, compositions and methods are clearly within the scope of the invention, as described herein. It will be appreciated that some features of the recycled glass composite slabs, and processes for preparing the same identified in some aspects, embodiments or examples as described herein may not be required in all aspects, embodiments or examples as described herein, and this specification is to be read in this context. It will also be appreciated that in the various aspects, embodiments or examples, the order of method or process steps may not be essential and may be varied.

BRIEF DESCRIPTION OF THE FIGURES Figure 1A: A composite slab of the present invention comprising 85% recycled glass (w/w) and 15% (w/w) polyester resin. Figure 1B: A cross-sectional view of the composite slab in Figure 1A. Figure 2: Flow diagram showing process steps to prepare the composite slab of Figure 1A and 1B. Figure 3: Surface of composite slab after 5 seconds and 5 minutes exposure to 200°C.

DETAILED DESCRIPTION Disclosed herein is are composite slabs comprising milled recycled glass and a cured polyester resin. In contrast to other composite materials, in some embodiments, the slabs of the present invention are substantially free of crystalline silica. In addition, the composite slabs comprise recycled glass which otherwise would have been disposed of in landfills. The composite slabs of the present invention are unique and provide distinct health and environmental benefits compared to other materials on the market.

Terms In the following description, reference is made to the accompanying drawings which form a part hereof, and which is shown, by way of illustration, several embodiments. It is understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present disclosure. With regards to the definitions provided herein, unless stated otherwise, or implicit from context, the defined terms and phrases include the provided meanings. Unless explicitly stated otherwise, or apparent from context, the terms and phrases below do not exclude the meaning that the term or phrase has acquired by a person skilled in the relevant art. The definitions are provided to aid in describing particular embodiments, and are not intended to limit the claimed invention, because the scope of the invention is limited only by the claims. Furthermore, unless otherwise required by context, singular terms shall include pluralities and plural terms shall include the singular. All publications discussed and/or referenced herein are incorporated herein in their entirety. Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is solely for the purpose of providing a context for the present disclosure. It is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present disclosure as it existed before the priority date of each claim of this application. Throughout this disclosure, unless specifically stated otherwise or the context requires otherwise, reference to a single step, composition of matter, group of steps or group of compositions of matter shall be taken to encompass one and a plurality (i.e., one or more) of those steps, compositions of matter, groups of steps or groups of compositions of matter. Thus, as used herein, the singular forms "a", "an" and "the" include plural aspects unless the context clearly dictates otherwise. For example, reference to "a" includes a single as well as two or more; reference to "an" includes a single as well as two or more; reference to "the" includes a single as well as two or more and so forth. Those skilled in the art will appreciate that the disclosure herein is susceptible to variations and modifications other than those specifically described. It is to be understood that the disclosure includes all such variations and modifications. The disclosure also includes all of the examples, steps, features, methods, compositions, coatings, processes, and coated substrates, referred to or indicated in this specification, individually or collectively, and any and all combinations or any two or more of said steps or features. The term "and/or", e.g., "X and/or Y" shall be understood to mean either "X and Y" or "X or Y" and shall be taken to provide explicit support for both meanings or for either meaning. Unless otherwise indicated, the terms "first," "second," etc. are used herein merely as labels, and are not intended to impose ordinal, positional, or hierarchical requirements on the items to which these terms refer. Moreover, reference to a "second" item does not require or preclude the existence of lower-numbered item (e.g., a "first" item) and/or a higher-numbered item (e.g., a "third" item). As used herein, the phrase "at least one of", when used with a list of items, means different combinations of one or more of the listed items may be used and only one of the items in the list may be needed. The item may be a particular object, thing, or category. In other words, "at least one of" means any combination of items or number of items may be used from the list, but not all of the items in the list may be required. For example, "at least one of item A, item B, and item C" may mean item A; item A and item B; item B; item A, item B, and item C; or item B and item C. In some cases, "at least one of item A, item B, and item C" may mean, for example and without limitation, two of item A, one of item B, and ten of item C; four of item B and seven of item C; or some other suitable combination. As used herein, the term "about", unless stated to the contrary, typically refers to +/- 10%, for example +/- 5%, of the designated value.

It is to be appreciated that certain features that are, for clarity, described herein in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features that are, for brevity, described in the context of a single embodiment, may also be provided separately or in any sub combination. Throughout the present specification, various aspects and components of the invention can be presented in a range format. The range format is included for convenience and should not be interpreted as an inflexible limitation on the scope of the invention. Accordingly, the description of a range should be considered to have specifically disclosed all the possible sub-ranges as well as individual numerical values within that range, unless specifically indicated. For example, description of a range such as from 1 to 5 should be considered to have specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 5, from 3 to 5 etc., as well as individual and partial numbers within the recited range, for example, 1, 2, 3, 4, 5, 5.5 and 6, unless where integers are required or implicit from context. This applies regardless of the breadth of the disclosed range. Where specific values are required, these will be indicated in the specification. Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps. The term "consists of", or variations such as "consisting of", refers to the inclusion of any stated element, integer or step, or group of elements, integers or steps, that are recited in context with this term, and excludes any other element, integer or step, or group of elements, integers or steps, that are not recited in context with this term. The reference to "substantially free" generally refers to the absence of that compound or component in the composition other than any trace amounts or impurities that may be present, for example this may be an amount by weight % in the total composition of less than about 1%, 0.1%, 0.01%, 0.001%, or 0.0001%. The composite slabs as described herein may also include, for example, impurities in an amount by weight % in the total composition of less than about 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.01%, 0.001%, or 0.0001%. As used herein, the term "hydroxyl" represents a -OH moiety.

As used herein, the term "carboxyl" or "carboxylic acid" represents a -CO 2 H moiety. As used herein the term "anhydride" refers to a compound derived from an organic diacid by elimination of a molecule of water. A diacid comprises two carboxyl groups. As used herein, the term "glycol" encompasses simple glycols, composed of any organic compound having two adjacent non-aromatic carbon atoms, each being substituted by a hydroxyl group, as well as compounds comprising two or more glycol moieties linked to one another by one or more ether bond, such as in the case of dialkylene glycols (e.g. diethylene glycol) and polyalkylene glycols (e.g., polyethylene glycol), as well as etherified derivatives thereof. As used herein, the term "polyol" is intended to include materials that contain two or more hydroxyl groups. Non-limiting examples of polyols include diols, triols, polyether polyols, polyacrylate polyols, polyester polyols, polycarbonate polyols, neopentyl glycol, and combinations thereof. As used herein, the term "ether" refers to an alkyl-O-alkyl group. As used herein, the term "alkyl" includes straight-chained, branched, and cyclic alkyl groups. Unless otherwise indicated, the alkyl groups typically contain from 1 to 20 carbon atoms. The alkyl groups may for example contain carbon atoms from 1 to 12, 1 to 10, or 1 to 8. Examples of "alkyl" as used herein include, but are not limited to, methyl, ethyl, n-propyl. n-butyl, n-pentyl, isobutyl, t-butyl, isopropyl, n-octyl, n-heptyl, ethylhexyl, cyclopentyl, cyclohexyl, cyclo heptyl, adamantyl, and norbornyl, and the like. Unless otherwise noted, alkyl groups may be mono- or polyvalent. As used herein, the term "alkenyl" means straight-chained, branched, and cyclic alkyl groups having one or more double carbon-carbon bonds and 2-20 carbon atoms, including, but not limited to, ethenyl, 1-propenyl, 2-propenyl, 2-methyl- propenyl, 1-butenyl, 2-butenyl, and the like. In some embodiments, the alkenyl chain is from 2 to 10 carbon atoms in length, from 2 to 8 carbon atoms in length, from 2 to 6 carbon atoms in length, or from 2 to 4 carbon atoms in length. As used herein, the term "alkynyl" means a straight or branched alkyl group having one or more triple carbon-carbon bonds and 2-20 carbon atoms, including, but not limited to, acetylene, 1 -propylene, 2-propylene, and the like. In some embodiments, the alkynyl chain is 2 to 10 carbon atoms in length, from 2 to 8 carbon atoms in length, from 2 to 6 carbon atoms in length, or from 2 to 4 carbon atoms in length. As used herein, the term "unsaturated" refers to a compound comprising one or more alkenyl or alkynyl functional groups (e.g. -C=C-), that are polymerisable and/or can react by addition e.g. maleic anhydride and styrene. As used herein, the term "saturated" refers to a compound that does not comprise any alkenyl or alkynyl functional groups that are polymerisable and/or can react by addition. For the purposes of the present disclosure, wherever the term "saturated dicarboxylic acid or anhydride" is utilized, it is to be understood that such term includes the aromatically unsaturated dicarboxylic acids, such as isophthalic acid, where the aromatic nuclei of such acids are generally regarded as saturated since the double bonds cannot readily be polymerised. As used herein, the term "vinyl" refers to a compound comprising one or more of the functional group -CH=CH 2, e.g. styrene. As used herein, the term "peroxide" refers to a compound comprising one or more of the moiety [O-O]2-, such as R-O-O-R, e.g. methyl ethyl ketone peroxide (MEKP).

Composite slab As used herein, the term "composite slab" refers to a single modular block that is compact and solid. The modular block may be any shape, for example square, circular, and rectangular. In some embodiments, the composite slab may be a modular block used to make panelling, flooring, veneers, architectural finishes, building material surfaces, and other surfaces. For example, the composite slabs may be suitable for use in living or working spaces, for example as a bench-top (e.g. kitchen benchtop). The size and thickness of the composite slab can vary depending on the specification required. It will be appreciated that the composite slab is not a loose granular material (e.g. discrete particles) and rather is compact and solid. For example, while the composite slab may comprise milled recycled glass particles, the particles are bound together in a solid cured resin matrix to form a single slab. In some embodiments, one or more composite slabs can be placed together to make panelling, flooring, veneers, architectural finishes, building material surfaces, and other surfaces. Other products include tabletops, countertops, architectural facings, walkways, home furnishings, patio furniture, decorative stone, indoor and outdoor tile, flooring, mantles, bathroom fixtures, wall facings, cutting boards, sinks, showers, tubs, and imitation stone structures, among others. In one embodiment, the composite slab is a kitchen bench-top.

Milled recycled glass The composite slab comprises milled recycled glass. The recycled glass may be derived from any suitable source including consumer sources (e.g. glass beer and wine bottles, containers, and beverage holders), the construction industry (e.g. broken windows) and the automotive industry (e.g. broken car windows). In a preferred embodiment, the recycled glass is made of only post-consumer recycled bottle glass, for example beer and wine bottles. Different colour combinations of glasses can be mixed together to produce an array of different products having different appearances. For example, clear, brown, green, and blue glass particles can be used alone or in various combinations to produce a spectrum of colours for the finished product. For example, the glass may comprise predominantly of clear glass with a small proportion of blue glass mixed in. For example, referring to Figure 1A and 1B, a composite slab was prepared from recycled glass, which when combined with the polyester resin and optional additional components (such as a black pigment) and subjected to pressure and temperature, resulted in a natural "stone" looking slab. It will be appreciated that the colour of the composite slab in Figure 1A and 1B can be varied through the addition of other pigments and/or dyes and also through mixing in different coloured recycled glass. In some embodiments, the composite slab may comprise recycled glass, which on average, equates to about 400 to 800 bottles of glass that would otherwise need to be processed and disposed of in landfills. This highlights the unique nature of the present invention, which provides a sustainable building product comprising glass waste. The recycled glass may be further milled to obtain a particle sizes of glass. As used herein, the term "milled" refers to the processing of glass particles to obtain smaller particle sizes (i.e. reduced to a finer particle size by grinding in a mill). For example, the recycled glass may be milled to micron size (e.g. less than 1 mm). In some embodiments or examples, using milled recycled glass of micron size may lead to one or more advantages such as improved physical and/or mechanical properties, for example a high degree of compaction and packing of the recycled glass within the composite slab and overall reduced porosity. Other advantages may include a polished "stone" like finish as opposed to speckled finish often obtained using larger sized aggregates. In some embodiments or examples, owing to the small micron glass particle size, the composite slabs do not require an additional filler material to fill the voids that often exist between larger aggregates. In one embodiment, the average particle size of the milled recycled glass is about 0.01 pm to about 100 pm. In some embodiments, the average particle size of the milled recycled glass is at least about 0.01, 0.05, 0.07, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.5, 2, 5, 10, 15, 20, 25, 50, 75, or 100 pm. In other embodiments, the average particle size of the milled recycled glass is less than about 100, 75, 50, 25, 20, 15, 10, 5, 2, 1.5, 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1, 0.07, 0.05, or 0.01 pm. Combinations of these average particle sizes to form various ranges are also possible, for example the average particle size of the milled recycled glass is about 0.05 to about 10 pm, about 0.07 to about 5 pm, or about 0.1 to about 1 pm. In one embodiment, the average particle size of the milled recycled glass is about 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, or 1 pm. In some embodiments, the milled recycled glass has a particle size distribution (PSD), wherein at least 90% of the particles (Peo) have a particle size of less than about 1,000 pm (i.e. 1 mm) 100, 50, 20, or 10 pm, or wherein 80% of the particles (P8o) have a particle size of less than 100, 50, 20, 10, 5 or 1 pm, or wherein 50% of the particles (P 5 0) have a particle size of less than 10, 5, or 1 pm. The average particle size/particle size distribution of the milled recycled glass may be measured by any suitable technique, for example size-sorting/screening using a suitable mesh or laser diffraction/scattering. In some embodiments, the milled recycled glass has a particle size of -140 mesh (e.g. 90% or more of the milled recycled glass particles pass through a 140 mesh sieve), -170 mesh, -200 mesh, -230 mesh, -270 mesh (-53 pm), -400 mesh (-37 pm), -625 mesh (-20 pm), -1250 mesh ( 10 pm), -2500 mesh (-5 pm), -5000 mesh (-2.5 pm), or -12000 mesh (-1 pm) determined according to U.S. Sieve No./Wire Mesh Size standards. In some embodiments, the milled recycled glass particles comprise a single type of glass particles having a given average particle size or a range of average particle sizes as defined above. In other embodiments, the milled recycled glass particles include a combination of two or more types of glass particles, each having a different average particle size or a different range of average particle sizes as defined above. The ranges of particle sizes between the two types can be overlapping or non overlapping. In some embodiments, the milled recycled glass is uniformly dispersed throughout the composite slab. For example, in this embodiment, it will be appreciated that there are no discrete layers of cured resin that do not comprise milled recycled glass. This uniform and homogenous distribution of the milled recycled glass throughout the composite slab can provide enhanced strength properties. An example of such distribution is observed in the cross-section of a composite slab in Figure 1A. In some embodiments, the composite slab comprises about 65% to about 95% (w/w) of milled recycled glass. In some embodiments, the composite slab comprises at least about 65%, 70%, 75%, 80%, 85%, 90%, or 95% (w/w) milled recycled glass. In other embodiments, the composite slab comprises less than about 95%, 90%, 85%, 80%, 75%, 70%, or 65% (w/w) milled recycled glass. Combinations of these % w/w values to form various ranges are also possible, for example the composite slab comprises about 70% to about 95% (w/w), or 80% to about 90% (w/w) milled recycled glass. In one embodiment, the composite slab comprises about 85% to about 87% (w/w) milled recycled glass. In some embodiments, the composite slab comprises at least about 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, or 95% (w/w) milled recycled glass. In other embodiments, the composite slab comprises less than about 95%, 94%, 93%, 92%, 91% 90%, 89%, 88%, 87%, 86%, 85%, 84%, 83%, 82%, 81%, or 80% (w/w) milled recycled glass. Combinations of these % w/w values to form various ranges are also possible, for example the composite slab comprises about 65% to about 95% (w/w), about 70% to about 95% (w/w), about 75% to about 95% (w/w), about 80% to about 95% (w/w), about 85% to about 95% (w/w), about 80% to about 90% (w/w), e.g. about 85% to about 87% (w/w) milled recycled glass. In some embodiments, the milled recycled glass is not coated with a silane material.

Cured polyesterresin The composite slab comprises milled recycled glass which is bound together by a matrix formed by a cured polyester resin. Therefore, in some embodiments, the composite slab comprises a cured reaction product of milled recycled glass and a polyester resin.

As used herein, the term "resin" refers to liquid materials that are capable of hardening permanently, e.g., by curing. For instance, some "resins" are thermosetting and the term "resin" may refer to the reactant or product, or both. When the resin is the product, e.g. cured, it may be referred to as a cured resin, for example a "cured polyester resin". As used herein, the term "cure" or "curing" refers to the process by which the polyester resin hardens via copolymerisation. The curing can be enhanced and/or sped up by applying heat and pressure. Composite slabs comprising milled recycled glass and a polyester resin form, when cured, form a strong matrix that binds the milled glass particles together to form the composite slab. In contrast, other types of resins used to manufacture composite products, were found to be problematic and provided inferior properties. In one embodiment, the polyester resin is a thermosetting resin which is able to be cured exothermically to form the cured polyester resin. In one embodiment, the composite slab comprises a cured thermoset polyester resin. It will be appreciated that a thermoset resin is different to a thermoplastic resin. For example, once cured, a thermoset resin cannot be melted, reshaped or remoulded (e.g. via applying heat). In contrast, cured thermoplastic resins can be reshaped or remoulded. In other words, the curing process is reversible in a thermoplastic resin but not reversible in a thermoset resin. According to at least some examples or embodiments described herein, composite slabs comprising a cured thermoset resin may provide additional advantages such as increased resistance to heat (e.g. upon contact with hot surfaces). In one embodiment, the polyester resin is an unsaturated polyester resin. The term unsaturated polyester resins according to the invention designates mixtures of one or more unsaturated polyesters with one or more unsaturated compounds, which can react with one another under formation of three-dimensional cross-linkages. For example, in some embodiments, the unsaturated polyester resin comprises an unsaturated polyester dissolved in reactive solvent comprising a vinyl monomer. For example, to form the cured polyester resin, in some embodiments, the curing reaction comprises the copolymerisation of the vinyl monomer in the reactive solvent with the double bonds of the unsaturated polyester. In the course of the curing, a three-dimensional network is formed. In the context of the present disclosure, when the unsaturated polyester is mixed with the vinyl monomer, the subsequent overall mixture may be referred to as the polyester resin. In some embodiments, the unsaturated polyester may be formed from a mixture of a polyester of an alpha-beta ethylenically unsaturated polycarboxylic acid or anhydride and a polyol monomer. For example, the unsaturated polyester may be a copolymer formed by the reaction of a polyol monomer (i.e. an organic alcohol containing multiple hydroxyl groups e.g. a diol, triol or tetrol) and an unsaturated dicarboxylic acid or anhydride monomer. Alternatively, the unsaturated polyester may be a copolymer formed by the reaction of a polyol monomer and a saturated dicarboxylic acid or anhydride monomer and the unsaturation may be introduced into the polyester by incorporation of an unsaturated dicarboxylic acid or anhydride monomer. Such saturated dicarboxylic acids or anhydride monomers increase the length of the polyester without adding additional crosslinking sites, which is a desired feature in some polyesters. Thus, in some embodiments, the unsaturated polyester may be a copolymer formed by the reaction of a polyol monomer, a saturated dicarboxylic acid or anhydride monomer, and an unsaturated dicarboxylic acid or anhydride monomer. In one embodiment, when present, the polyester comprises a saturated dicarboxylic acid or anhydride monomer selected from the group consisting of suberic acid, glutaric acid, sebacic acid, adipic acid, dodecanedioic acid, dimeric fatty acids, phthalic anhydride, phthalic acid, isophthalic acid, terephthalic acid, caboxypthalanilic acid, 2,3- and 2,6-naphthalene dicarboxylic acids, hexahydrophthalic acid and 1,4 cyclohexane dicarboxylic acid or a combination thereof. In a preferred embodiment, the saturated dicarboxylic acid monomer is isophthalic acid. In some embodiments, the unsaturated polyester comprises about 5% to about 95% (w/w) unsaturated dicarboxylic acid or anhydride monomer. In one embodiment, when present, the polyester comprises an unsaturated dicarboxylic acid or anhydride monomer selected from the group consisting of maleic acid, maleic anhydride, fumaric acid, itaconic acid, tetrahydrophthalic acid, endomethylene tetrahydrophthalic acid, and hexachloro endomethylene tetrahydrophthaic acids, or a combination thereof. In one embodiment, when present, the unsaturated dicarboxylic anhydride monomer is maleic anhydride. In some embodiments, the unsaturated polyester comprises about 5 % to about 95% (w/w) saturated dicarboxylic acid or anhydride monomer.

In one embodiment, the polyol monomer may be a saturated or unsaturated alcohol. In another embodiment, the polyol monomer may be a glycol. The glycol may be selected, for example, from ethylene glycol, 1,2-propylene glycol, 1,3-butanediol, 1,4-butanediol, diethylene glycol, dipropylene glycol, neopentyl glycol (2,2 dimethylpropane-1,3-diol), or a combination thereof. In one preferred embodiment, the polyol monomer is neopentyl glycol. In some embodiments, the unsaturated polyester comprises about 5 % to about 95% (w/w) polyol monomer. In one embodiment, the polyester resin may comprise an unsaturated polyester copolymer which is the reaction product of isophthalic acid and neopentyl glycol monomers and an unsaturated carboxylic acid or anhydride monomer (e.g. a maleic anhydride monomer). In one embodiment, the polyester resin comprises a polyester and a vinyl monomer. In some embodiments, the vinyl monomer can serve as the solvent for the polyester while also acting as the cross-linker during the co-polymerisation in the course of curing. Examples of suitable vinyl monomers used in the polyester resin include styrene, p-vinyltoluene, a-methylstyrene, vinyl toluene, divinyl benzene, vinyl naphthalene, methyl acrylate, methyl methacrylate, diallyl phthalate, di- and polyisocyantes, and triallyl cynurate. In one embodiment, the vinyl monomer is styrene. In one embodiment, the polyester resin comprises an unsaturated polyester copolymer which is the reaction product of isophthalic acid and neopentyl glycol monomers and an unsaturated carboxylic acid or anhydride monomer (e.g. a maleic anhydride monomer), and a styrene monomer. In some embodiments, the polyester resin comprises about 30% to about 60% w/w vinyl monomer, and about 40% to about 70% (w/w) unsaturated polyester. In some embodiments, the curing of the polyester resin is initiated by the addition of a polymerization initiator which catalyses the cross-linking of the vinyl monomer and the unsaturated polyester components of the resin to form a cured polyester resin. In one embodiment, the initiator is a free-radical initiator. A number of suitable initiators are known in the art and are widely available commercially. The choice of polyester resin will dictate the choice of available initiators, and the amounts that should be used to initiate catalysing the polymerization reaction. In one embodiment, the initiator is a peroxide. Typical peroxides used as initiators include ketone hydroperoxidases such as methyl ethyl ketone peroxide (MEKP), benzyl peroxide (BP), cyclohexanone peroxide (CHP), acetyl acetone peroxide (AAP), tertiary butylperoctoate (TBPO), tertiary butyl perhexanoate (TBPH) and tertiary butyl perbenzoate (TBPB). In one embodiment, for polyester and vinyl-containing monomers, methyl ethyl ketone peroxide (MEKP) is a preferred initiator. The initiator may be provided as a solution or paste which may be further mixed with a plasticizer such as a phthalate (e.g. dimethyl phthalate). In some embodiments, using methyl ethyl ketone peroxide (MEKP) as the initiator may lower the temperature required for the curing of the polyester resin. The initiator can be used in any effective amount, usually up to about 2.5% (w/w) more preferably about 0.1 up to about 2% (w/w) most preferably about 1 to about 2% (w/w) of the total weight of the polyester resin. The temperature of the system may also influence the amount of initiator to be introduced. In some embodiments, one or more promoters may be added to the polyester resin to accelerate the curing. Examples of promoters that may be used include cobalt naphthenate, cobalt octoate, vanadium naphthenate, vanadium octoate, or dimethyl aniline. In some embodiments, the cured polyester resin can also include a number of additional components including, without limitation, a coupling agent, a wetting agent, and an air release agent. If present, the coupling agent is a chemical substance capable of reacting with both the glass particles and the resin matrix of a composite material. Any suitable coupling agent can be used in accordance with the present invention. Exemplary coupling agents include, without limitation, silane-based coupling agents, titanate based coupling agents, aluminium based coupling agent, and polymer coupling agents. The coupling agents can be introduced in amounts up to about 10% (w/w) relative to the total weight of the resin, more preferably up to about 5% (w/w), preferably in amount up to about 1% (w/w) more preferably about 0.1 to about 0.5 %

(w/w). If included in the polyester resin, the wetting agent is a chemical substance that reduces the surface tension of the liquid polyester resin, i.e., prior to curing, and therefore is useful in allowing the polyester resin to produce a matrix that is substantially free of voids by causing the liquid polyester resin to spread between the glass particles prior to curing. Any suitable wetting agent can be used in accordance with the present invention. Useful wetting agents include, for example, boric acid esters, phosphate esters, fatty acid salts, polyethers and others. The wetting agents can introduced in amounts up to about 1.5 % (w/w), relative to the total weight of the polyester resin, more preferably up to about 1 % (w/w) most preferably between about 0.1 to about 1 % (w/w). In some embodiments, the polyester resin may also comprise an air release (or de-foaming) agent, which promotes the elimination of air in the polyester resin as it cures. Any suitable air release agent can be used in accordance with the present invention. The air release agents can be introduced in amounts up to about 1.5% (w/w) relative to the total weight of the resin, more preferably up to about 1% (w/w) most preferably between about 0.3 to about 1% (w/w). In some embodiments, the polyester resin may also include a UV stabiliser to improve UV resistance to discolouration. In one embodiments, the polyester resin has a liquid viscosity of about 100 mPa.s to about 5000 mPa.s when measured using a Brookfield RVT at sp. 3/100 rpm. For example. The polyester resin may have a liquid viscosity of about 800 mPa.s. to about 1000 mPa.s. In one embodiment, the polyester resin has a liquid density of about 1.00 to about 2.00 g.cm-3 . For example, the polyester resin may have a liquid density of about 1.10 gcm- 3 .

In some embodiments, the cured polyester resin may be present in the composite slab in an amount of about 5% to about 35% (w/w). In some embodiments, the composite slab comprises at least about 5%, 10%, 15%, 20%, 25%, 30% or about 35% (w/w) cured polyester resin. In other embodiments, the composite slab comprises less than about 35%, 30%, 25%, 20%, 15%, 10%, or 5% (w/w) cured polyester resin. Combinations of these cured polyester resin % w/w values to form various ranges are also possible, for example the composite slab comprises about 10% to about 30% (w/w) cured polyester resin. In one embodiment, the composite slab comprises about 10% to about 20% cured polyester resin, for example about 12% to about 15% (w/w) cured polyester resin. It will be appreciated that % w/w different ranges of cured polyester resin will be required depending on the % w/w amount of milled recycled glass used to form the composite slab. In one embodiments, the composite slab comprises about 80% to about 90% (w/w) milled recycled glass and about 10% to about 20% (w/w) cured polyester resin.

For example, the composite slab may comprise about 85% to about 87% (w/w) milled recycled glass and about 12% to about 15% (w/w) cured polyester resin. In some embodiments, the ratio of milled recycled glass to cured polyester resin in the composite slab may be about 1:1 to 20:1. In some embodiments, the ratio of milled recycled glass to cured polyester resin may be at least about 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, 19:1, or 20:1. In other embodiments, the ratio of milled recycled glass to cured polyester resin may be less than about 20:1, 19:1, 18:1, 17:1, 16:1, 15:1, 14:1, 13:1, 12:1, 11:1, 10:1, 9:1, 8:1, 7:1, 6:1, 5:1, 4:1, 3:1, 2:1, or about 1:1. Combinations of these ratios are possible, for example, the ratio of milled recycled glass to cured polyester resin may about 4:1 to about 10:1. In one embodiment, the resin does not comprise an epoxy resin. In one embodiment, the resin does not comprise a thermoplastic resin In one embodiment, the composite slab comprises a cured reaction product of: a) about 65% to about 95% (w/w) of milled recycled glass; and b) about 5% to about 35% (w/w) of a polyester resin. In one embodiment, the composite slab comprises a cured reaction product of: a) about 65% to about 95% (w/w) of milled recycled glass; and b) about 5% to about 35% (w/w) of a polyester resin. wherein the average particle size of the milled recycled glass is about 0.01 pm to about 100 pm. The embodiments described above in relation to the milled recycled glass and polyester for the composite slab are also applicable for the milled recycled glass and polyester resin of the cured reaction product.

Other additives. The composite slab may comprise one or more optional additional non crystalline additives. For example, the composite slab may comprise one or more optional non-crystalline additives which can be introduced in amounts of up to 10% (w/w) of the overall slab. In some embodiments, the optional one or more non-crystalline additives that may be added to the composite slab includes a wetting agent, a dye and/or pigment, and a filler.

Examples of suitable fillers include calcium carbonate powder, clay, bentonite, alumina powder, amorphous silica, talc, barium sulfate, mica, aluminium hydroxide, cellulose yarn, silica sand, river sand, white marble, marble scrap, and crushed stone. When present, the composite slab may comprise up to about 10% (w/w) filler, for example about 1% to about 5% (w/w) filler, for example about 1% to about 2% (w/w) filler. Alternatively, in some embodiments, the composite slab does not comprise a filler. According to some embodiments or examples, the composite slabs described herein have a low porosity (e.g. less than about 0.01) and therefore owing the milled recycled glass size. One or more pigments and/or dyes can be added to the composite slab, which when used in combination with the glass particles achieves a desired coloured effect. When present, the composite slab may comprise up to about 2% (w/w) pigment and/or dye, for example about 1% to about 2% (w/w), more preferably about 1% (w/w), most preferably about 0.01 to about 0.5 % (w/w) pigment and/or dye. Any suitable pigment and/or dye can be used to add colour to the composite slab. For example, the pigment and/or dye may be white, jade, red, or blue. For example the white pigment and/or dye may comprise titanium dioxide. It will be appreciated that the selection of pigment and/or dye will be based on the desired colour of the composite slab. As well as optionally being present as part of the polyester resin, an additional wetting agent may be incorporated separately into the composite slab. When present, the composite slab may comprise up to about 2% (w/w) wetting agent, for example about 1% to about 2% (w/w), more preferably about 1% (w/w), most preferably about 0.01 to about 0.5 % (w/w) wetting agent. In some embodiments or examples, the composite slab has a low porosity (e.g. less than 0.01) which may lead to one or more advantages, such as reduced moisture absorption. Such a reduced moisture environment may prevent growth of one or more microorganisms on or in the composite slab. Accordingly, in some embodiments, the composite slab does not comprise an antimicrobial agent. In some embodiments, the composite slab does not comprise marble (e.g. calcium carbonate), quartz, granite, and feldspar.

Process for preparing composite slab The composite slabs of the present invention are prepared by mixing milled recycled glass with a polyester resin and subsequently curing the polyester resin to form the composite slab. A general process outline is provided in Figure 2. Thus, in one embodiment, there is provided a process for preparing a composite slab, comprising the step of a) curing a mixture of milled recycled glass and a polyester resin in a die to form a composite slab. In one embodiment, the mixture comprises about 65% to about 95% (w/w) of milled recycled glass. In some embodiments, the mixture comprises at least about 65%, 70%, 75%, 80%, 85%, 90%, or 95% (w/w) milled recycled glass. In other embodiments, the mixture comprises less than about 95%, 90%, 85%, 80%, 75%, 70%, or 65% (w/w) milled recycled glass. Combinations of these % w/w values to form various ranges are also possible, for example the mixture comprises about 70% to about 95% (w/w), or 80% to about 90% (w/w) milled recycled glass. In one embodiment, the mixture comprises about 85% to about 87% (w/w) milled recycled glass. In some embodiments, the mixture comprises at least about 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, or 95% (w/w) milled recycled glass. In other embodiments, the mixture comprises less than about 95%, 94%, 93%, 92%, 91%, 90%, 89%, 88%, 87%, 86%, 85%, 84%, 83%, 82%, 81%, or 80% (w/w) milled recycled glass. Combinations of these % w/w values to form various ranges are also possible, for example the mixture comprises about 65% to about 95% (w/w), about 70% to about 95% (w/w), about 75% to about 95% (w/w), about 80% to about 95% (w/w), about 85% to about 95% (w/w), about 80% to about 90% (w/w), e.g. about 85% to about 87% (w/w) milled recycled glass. In one embodiment, the recycled glass may be milled to micron size (e.g. less than 1 mm). In one embodiment, the average particle size of the milled recycled glass in the mixture is about 0.01 pm to about 100 pm. In some embodiments, the average particle size of the milled recycled glass in the mixture is at least about 0.01, 0.05, 0.07, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.5, 2, 5, 10, 15, 20, 25, 50, 75, or 100 pm. In other embodiments, the average particle size of the milled recycled glass in the mixture is less than about 100, 75, 50, 25, 20, 15, 10, 5, 2, 1.5, 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1, 0.07, 0.05, or 0.01 pm. Combinations of these average particle sizes to form various ranges are also possible, for example the average particle size of the milled recycled glass in the mixture is about 0.05 to about 10 pm, about 0.07 to about 5 pm, or about 0.1 to about 1 pm. In one embodiment, the average particle size of the milled recycled glass in the mixture is about 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, or 1 pm. In some embodiments, the milled recycled glass has a particle size distribution (PSD), wherein at least 90% of the particles (Pgo) have a particle size of less than about 1,000 pm (i.e. 1 mm) 100, 50, 20, or 10 pm, or wherein 80% of the particles (P 8 0) have a particle size of less than 100, 50, 20, 10, 5 or 1 pm, or wherein 50% of the particles (P 5 0) have a particle size of less than 10, 5, or 1 pm. The average particle size/particle size distribution of the milled recycled glass may be measured by any suitable technique, for example size-sorting/screening using a suitable mesh or laser diffraction/scattering. In some embodiments, the milled recycled glass has a particle size of -140 mesh (e.g. 90% or more of the milled recycled glass particles pass through a 140 mesh sieve), -170 mesh, -200 mesh, -230 mesh, -270 mesh (-53 pm), -400 mesh (-37 pm), -625 mesh (-20 pm), -1250 mesh ( 10 pm), -2500 mesh (-5 pm), -5000 mesh (-2.5 pm), or -12000 mesh (-1 pm) determined according to U.S. Sieve No./Wire Mesh Size standards. In some embodiments, the milled recycled glass particles in the mixture comprise a single type of glass particles having a given average particle size or a range of average particle sizes as defined above. In other embodiments, the milled recycled glass particles in the mixture include a combination of two or more types of glass particles, each having a different average particle size or a different range of average particle sizes as defined above. The ranges of particle sizes between the two types can be overlapping or non-overlapping. In some embodiments, the mixture comprises a polyester resin. In some embodiments, the mixture comprises about 5% to about 35% (w/w) polyester resin. In some embodiments, the mixture comprises at least about 5%, 10%, 15%, 20%, 25%, 30% or about 35% (w/w) polyester resin. In other embodiments, the mixture comprises less than about 35%, 30%, 25%, 20%, 15%, 10%, or 5% (w/w) polyester resin. Combinations of these polyester resin % w/w values to form various ranges are also possible, for example the mixture comprises about 10% to about 30% (w/w) polyester resin. In one embodiment, the mixture comprises about 10% to about 20% polyester resin, for example about 12% to about 15% (w/w) polyester resin. It will be appreciated that % w/w different ranges of polyester resin will be required depending on the % w/w amount of milled recycled glass used to form the composite slab.

In one embodiments, the mixture comprises about 80% to about 90% (w/w) milled recycled glass and about 10% to about 20% (w/w) polyester resin. For example, the mixture may comprise about 85% to about 87% (w/w) milled recycled glass and about 12% to about 15% (w/w) polyester resin. In some embodiments, the ratio of milled recycled glass to polyester resin in the mixture may be about 1:1 to 20:1. In some embodiments, the ratio of milled recycled glass to polyester resin may be at least about 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, 19:1, or 20:1. In other embodiments, the ratio of milled recycled glass to polyester resin may be less than about 20:1, 19:1, 18:1, 17:1, 16:1, 15:1, 14:1, 13:1, 12:1, 11:1, 10:1, 9:1, 8:1, 7:1, 6:1, 5:1, 4:1, 3:1, 2:1, or about 1:1. Combinations of these ratios are possible, for example, the ratio of milled recycled glass to polyester resin may about 4:1 to about 9:1. The embodiments defined above in relation to the milled recycled glass for the composite slab (e.g. % w/w, particle size etc.) are also applicable for the milled recycled glass described in the process of preparing the composite slab. The embodiments defined above in relation to the polyester resin for the composite slab are also applicable for the polyester resin described in the process of preparing the composite slab. The process comprises curing the glass and resin mixture at a temperature of about 50°C to about 300°C and at a pressure of about 200 tonnes/m 2 to about 700 tonnes/m2 . The introduction of pressure and temperature not only accelerates the curing process of the polyester resin, but also provides the structural integrity of the composite slab by compacting the milled recycled glass and resin mixture under pressure and heat into a dense composite slab, as seen in Figure 1A and Figure 1B. In one embodiments, the curing is at a temperature of about 50°C to about 300°C. In some embodiments, the curing is at a temperature of at least about 50, 60, 70, 80, 90, 100, 120, 140, 160, 180, 200, 220, 240, 260, 280, or 300°C. In other embodiments, the curing is at a temperature of less than about 300, 280, 260, 240, 220, 200, 180, 160, 140, 120, 100, 90, 80, 70, 60, or 5 0 °C. Combinations of these temperatures to form various ranges are also possible, for example the curing is at a temperature of about 50°C to about 260°C, about 50°C to about 200°C, about 60°C to about 140°C, or about 60°C to about 100°C, for example about 70°C. In one embodiment, the curing is at a pressure effective to cure the polyester resin of about 200 tonnes/m 2 to about 700 tonnes/m 2 . In some embodiments, the curing is at a pressure of at least about 200, 300, 400, 500, 600, or 700 tonnes/m 2. In other embodiments, the curing is at a pressure of less than about 700, 600, 500, 400, 300, or 200 tonnes/m 2 . Combinations of these pressures to form various ranges are also possible, for example, the curing is at a pressure of about 200 tonnes/m 2 to about 600 tonnes/m2 , about 300 tonnes/m 2 to about 600 tonnes/m 2 , for example about 400 tonnes/m2 . In some embodiments, the curing is at a pressure of at least about 200, 225,250,275,300,325,350,375,400,425,450,475,500,525,550,575,600,625, 650, 675, or 700 tonnes/m 2 . In other embodiments, the curing is at a pressure of less than about700,675,650,625,600,575,550,525,500,475,450,425,400,375,350, 325, 300, 275, 250, 225, or 200 tonnes/m 2 . Combinations of these pressures to form various ranges are also possible, for example, the curing is at a pressure of about 200 tonnes/m2 to about 650 tonnes/m 2 , about 200 tonnes/m 2 to about 600 tonnes/m 2 , for example about 250 tonnes/m 2 to about 500 tonnes/m 2 . In some embodiments, the curing is at a pressure of about 300 tonnes/m 2 to about 500 tonnes/m 2 , for example about 325 tonnes/m 2 to about 450 tonnes/m 2, e.g. about 400 tonnes/m 2 . In some embodiments or examples, curing the mixture of milled recycled glass and polyester resin under pressure may lead to one or more advantages such as improved structural integrity of the composite slab (e.g. reduced pinholes, cracking and porosity) by compacting the milled recycled glass and resin mixture under pressure and heat into a dense composite slab. In one embodiment, the curing is for a period of time of about 20 minutes to about 120 minutes. In some embodiments, the curing is for a period of time of at least about 20, 30, 40, 50 ,60 ,70, 80, 90,100, 110, or 120 minutes. In other embodiments, the curing is for a period of time of less than about 120, 110, 100, 90, 80, 70, 60, 50, 40, 30, or 20 minutes. Combinations of these curing times to form various ranges are also possible, for example the curing is for a period of time of about 30 minutes to about 90 minutes, or about 40 minutes to about 80 minutes. In one embodiment, the curing is for a period of time of less than 120 minutes, for example about 60 minutes. It will be appreciated that the process may comprise any combination of the above curing pressures, temperatures and times. For example, in one embodiment, the curing is at a temperature of about 50°C to about 300°C, and at a pressure of about 200 tonnes/m2 to about 700 tonnes/m2 . In one embodiment, the curing is at a 2 temperature of about 50°C to about 300°C, and at a pressure of about 200 tonnes/m to about 600 tonnes/m 2. In one embodiment, the curing is at a temperature of about

50°C to about 300°C, and at a pressure of about 200 tonnes/m 2 to about 500 tonnes/m2 . In one embodiment, the curing is at a temperature of about 50°C to about 300°C, and at a pressure of about 200 tonnes/m 2 to about 600 tonnes/m 2 . In one embodiment, the curing is at a temperature of about 50°C to about 300°C, and at a pressure of about 200 tonnes/m 2 to about 500 tonnes/m 2 . In one embodiment, the curing is at a temperature of about 60°C to about 100°C, and at a pressure of about 300 tonnes/m2 to about 600 tonnes/m2 . In one embodiment, the curing is at a temperature of about 70°C, and at a pressure of about 400 tonnes/m 2

. In one embodiment, the curing is at a temperature of about 50°C to about 300°C, and at a pressure of about 200 tonnes/m 2 to about 700 tonnes/m 2, and for a period of time of about 20 minutes to about 120 minutes. In one embodiment, the curing is at a temperature of about 60°C to about 100°C, and at a pressure of about 300 tonnes/m2 to about 600 tonnes/m2 , and for a period of time of about 40 minutes to about 80 minutes. In one embodiment, the curing is at a temperature of about 70°C, and at a pressure of about 400 tonnes/m 2 , and for a period of time of about 60 minutes. The curing of the mixture of milled recycled glass and a thermoset polyester resin in a die to form the composite slab may be performed using a platen press. For example, the platen press may be configured to cure a mixture of milled recycled glass and a polyester resin in a die to form the composite slab described herein. The platen press may be configured to provide a curing temperature, curing pressure and/or curing time as described herein. In one embodiment, the platen press may be a heated platen press, for example an oil heated platen press. The heated platen press may provide one or more further advantages such as even and consistent heat transfer across the milled recycled glass polyester resin mixture to produce a composite slab with good structural properties, such as low porosity and uniform distribution of recycled glass. In one embodiment, the process further comprises the step of al) mixing the milled recycled glass and polyester resin in to form a homogeneous milled recycled glass resin mixture prior to the curing at step a). The recycled glass and resin can be mixed using any conventional mixer used in the building industry, for example a paddle mixer. In one embodiment, an initiator is added to the mixture at step al) to initiate the curing at step a). This mixture may be called the "initiated mixture". In one embodiment, the initiator is a peroxide. The embodiments defined above in relation to the initiator for the composite slab are also applicable for the initiator for the process of preparing the composite slab. In one embodiment, the initiated mixture is mixed for about 5 minutes to about 30 minutes. In some embodiments, the initiated mixture is mixed for at least about 5, 10, 15, 20, 25, or 30 minutes. In other embodiments, the initiated mixture is mixed for less than about 30, 25, 20, 15, 10, or 5 minutes. Combinations of these mixing times to form various ranges are also possible, for example the initiated resin mixture is mixed for about 5 minutes to about 10 minutes. In one embodiment, the initiated mixture is mixed for about 5, 6, 7, 8, 9, or 10 minutes, preferable about 6 minutes to about 8 minutes. In one embodiment, the initiated mixture is mixed at a speed of about 20 rpm to about 100 rpm. In one embodiment, the initiated mixture is mixed at a speed of at least about 30 rpm. In one embodiment, a release agent is applied to the surface of the die prior to the curing at step a). The release agent can be a liquid which may be wiped onto the surface of the die. Examples of suitable release agents include, but are not limited to, wax, poly(vinyl alcohol) and silicone. In one embodiment, the release agent is applied as a single coat to the die. In another embodiment, two or more coats of release agent are applied to the die, for example two coats or three coats. The release agent can be sprayed onto the surface via aerosol application or wiped. In some embodiments, the process at step a) or al) further comprises one or more non-crystalline additives selected from a wetting agent, a dye, a pigment, and a filler. The embodiments defined above in relation to the wetting agent, dye, pigment and/or filler for the composite slab are also applicable for the wetting agent, dye, pigment and/or filler for the process of preparing the composite slab. In some embodiments, the milled recycled glass is not pre-treated prior to curing the mixture of milled recycled glass and a polyester resin in a die to form a composite slab. For example, the milled recycled glass has not been coated with a silane material.

Crystalline silica free One of the other advantages of the composite slabs of the present invention is that they are substantially free of crystalline silica. As used herein "silica" is the generic term for minerals and other materials with the chemical formulaSiO 2. Silica collectively describes crystalline and non-crystalline forms. "Crystalline silica" occurs in nature and can also be artificially produced by heating and pressurising glasses or other amorphous silicates. The toxic form of silica is its crystalline form. Toxicity is related to the extremely small particles of silica that are respirable, that is, they can reach the inner parts of the respiratory system. Respirable particles are those that can penetrate the airways of the respiratory system with a particle size less than ten micrometres (below 10 pm). When respirable crystalline silica particles are inhaled, lung tissue reacts by developing fibrous tissue around trapped silica particles. Over time and continuing exposure, this tissue damage increases, and reduces the ability of oxygen to be absorbed into the body. Human exposure to silica (usually as quartz) occurs most often during occupational activities that involve movement of earth, including mining, tunnelling, quarrying, or manufacturing or using silica-containing products, and the generation of respirable dusts. Trades and industries that are involved in such work include brick manufacture, construction, metal foundries, sandblasting, ship and bridge repair, glass manufacture, ceramics manufacture, the refractory industry, and the like. As such, occupational exposure to crystalline silica dust constitutes a serious health hazard. This health hazard is also a concern for consumers using products containing crystalline silica and tradesman building products containing crystalline silica. The primary health concerns in those exposed to silica dust are the fibrogenic capacity of the inhaled silica particles that can lead to the development of silicosis as well as an increased risk of tuberculosis. In general, materials containing more than 1% crystalline silica are considered a health and safety issue. Accordingly, in some embodiments, the composites slabs comprise less than 1%, 0.1%, 0.01%, 0.001%, or 0.0001%. crystalline silica. In some embodiments, the composite slabs are substantially free of crystalline silica. In the context of the present invention, "substantially free" means less than about 1% (w/w) of crystalline silica. In some embodiments, the composite slabs are substantially free of quartz. In the context of the present invention, "substantially free" means less than about 1% (w/w) of quartz.

Advantageously, the milled recycled glass composite slabs of the present invention are also prepared by methods which finely controls the temperature and pressure to ensure that substantially no crystalline silica forms and subsequently the milled recycled glass composite slabs remain substantially free of crystalline silica. For example, curing the mixture of milled recycled glass and polyester resin curing at a 2 temperature of about 50°C to about 300°C, and at a pressure of about 200 tonnes/m to about 700 tonnes/m 2, and for a period of time of about 20 minutes to about 120 minutes produces a composite slab that is substantially free of crystalline silica (i.e. comprises less than about 1% (w/w) crystalline silica).

Properties of the composite slab In one embodiment, the composite slab is relatively colourfast to light. For example, the composite slab may have a colour fastness to light rating of at least 2, 3, 4, 5, 6, or 7 out of 7. For example, the composite slab may have a colour fastness of about 6-7 out of 7, when measured under Australian Standard designation AS 2001.2.B02:2001 (Colourfastness Tests - colourfastness to Artificial Light: Xenon Arc Fading Lamp Test (ISO 105-B02-1994 MOD) - 1 being severe change, 7 being no change. In some embodiments, the composite slab is deemed to satisfy flammability testing under Australian/NZ Standard AS/NZS 1530.3:1999. For example, in some embodiments, the composite slab may have an ignitability index of less than about 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1 out of 20. In some embodiments, the composite slab may have a spread of flame index of less than about 8, 7, 6, 5, 4, 3, 2, or 1 out of 10. In some embodiments, the composite slab may have a heat evolved index of less than about 8, 7, 6, 5, 4, 3, 2, or 1 out of 10. In some embodiments, the composite slab may have a smoke developed index of less than about 8, 7, 6, 5, 4, 3, 2, or 1 out of 10. In one embodiments, the porosity of the composite slab (i.e. the fraction of the volume of voids present in the composite slab over the total volume of the composite slab) is about 0.001 to about 0.10. In some embodiments, the porosity of the composite slab is less than about 0.10, 0.08, 0.06, 0.04, 0.02, 0.01, 0.008, 0.006, 0.004, 0.002, or 0.001. In one embodiment, the porosity of the composite slab is less than about 0.01. In one embodiment, the porosity of the composite slab is about 0.001 to about 0.10. The porosity may be measured by any suitable means, for example using industry test standard BS EN 1936:2006. In some embodiments, the moisture absorption of the composite slab is less than 1%, 0.5%, 0.1%, 0.8%, 0.6%, 0.4%, 0.2%, 0.1%, 0.08%, 0.06% or 0.04% when measured using industry standard ASTM C97. Referring to Figure 1A, the cross-section of the composite slab highlights the dense nature of the slab with low porosity, and also minimal to no pinholes and/or cracks. In some embodiments, the low porosity of the composted slabs can provide certain advantages, including resistance to staining where liquids can leak into the composite slab. In some embodiments, the composite slab weighs about 10 kg to about 300 kg. In some embodiments, the composite slab weighs about at least about 50, 60, 70, 80, 90, 100, 120, 140, 160, 180, 200, 220, 240, 260, 280, or 300 kg. In other embodiments, the composite slab weighs less than about 300, 280, 260, 240, 220, 200, 180, 160, 140, 120, 100, 90, 80, 70, 60 or 50 kg. Combinations of these weights are also possible to form various ranges, for example the composite slab weights about 180 kg to about 290 kg, or about 90 kg to about 100 kg. Other weights are also possible. The weight can be measured by any suitable means, such as conventional mass scales. In some embodiments, the composite slab has an area density of about 10 kg/m2 to about 100 kg/m 2 . In some embodiments, the composite slab has an area density of at least about 10, 20, 30, 40, 50, 60, 70, 80, 90 or 100 kg/m 2 . In other embodiments, the composite slab has an area density of less than about 100, 90, 80, 70, 60, 50, 40, 30, 20, or 10 kg/m 2 . Combinations of these area densities are also possible to form various ranges, for example, the composite slab has an area density of about 40 kg/m2 to about 50 kg/m 2 , or about 20 kg/m2 to about 40 kg/m 2 . Other area densities are also possible which will depend on the amount of recycled glass included in the composite slab. The area density may be measured by any suitable means, for example industry test standard ASTM C97. The dimensions of the composite slab can vary depending on the size of the die used in the process. Therefore, it will be appreciated that composite slabs of various size dimensions can be prepared. For example, the composite slab may have a dimension of about 3000 mm x 1500 mm x 20 mm. In another example, the composite slab may have a dimension of about 3000 mm x 1500 mm x 10 mm. In another example, the composite slab may have a dimension of about 2000 mm x 1500 mm x 20 mm. Other dimensions are also contemplated.

It will be apparent that, according to at least some examples or embodiments described herein, the composite slabs and/or process for preparing the composite slabs described herein can provide one or more advantages, including on or more of: * little to no pinholes present in the dense composite slab; • minimal blotching in the composite slab; * minimal to no cracking throughout the composite slab highlighting its strong structural integrity; * even distribution of the milled recycled glass throughout the composite slab; • low porosity resulting in good stain resistance and low moisture absorption; • scratch, stain and/or impact resistance highlighting the composite slabs durability; • UV protection; and/or * smooth natural polish finish.

EXAMPLES In order that the invention may be more clearly understood, particular embodiments of the invention are described in further detail below by reference to the following non-limiting experimental materials, methodologies and examples.

Example 1: Preparation of a composite slab A composite slab was prepared following the general flowchart outlined in Figure 2. Fine 40/70 0.5-2.0 mil profile recycled glass was obtained from GlassBlast TM which was further milled to micron size with an average particle size of about 0.01 pm to about 100 pm. An isophthalic acid/neopentyl glycol based polyester resin was obtained from Allnex (PolyplexTM ISO-NPG Solid Surface Resin). The polyester resin is initiated by a peroxide initiator (methyl ethyl ketone peroxide (MEKP)) supplied as Butanox M-50 from Allnex. A mixture comprising 85% (w/w) of the milled recycled glass and 12% (w/w) liquid polyester resin (i.e. uncured resin) was prepared via mixing with a paddle mixer. To the glass and resin mixture, the wetting agent and black pigment is added. To initiate the curing of the polyester resin, the Butanox M-50 initiator is added to the glass and resin mixture. The mixture was then mixed for about 6 to 8 minutes before being poured into a die which has been pre-coated with a release agent.

The die and the initiated glass resin mixture was then placed in between two integrated oil heated platens in a Platen Press. The Platen Press was operated at a pressure of 400 tonnes/m2 and at a temperature of 70°C for 60 minutes to form the composite slab. The composite slab has dimensions of 3000 mm x 1500 mm x 10 mm. A portion of the slab is shown in Figure 1A and Figure 1B.

Example 2: Composite slab demonstrates good colourfastness to light The composite slab had its colourfastness tested under Australian Standard AS 2001.2.B02:2001 (Colourfastness Tests - colourfastness to Artificial Light: Xenon Arc Fading Lamp Test (ISO 105-B02-1994 MOD). Briefly, the composite slab was exposed to a Xenon arc light source for a set period. This set period is determined by the rate of fading of Standard Blue Wool Standards (ISO 105-B08), which is tested on a water cooled Atlas Ci4000 Weatherometer at 63degC black panel temperature and 30% relative humidity at 420nm. Exposed with SDC standard blue scales. Light filters used: Outer filter: Soda-Lime and Inner filter: S Borosilicate. Modification: Test terminated when blue wool standard 6 changed shade equivalent to 3 on the standard grey scale. The colourfast rating of the composite slab is conducted under D65 (Artificial Daylight) light source in a rating booth. The colour fading change is rated against a 1-7 scale, where 7 = no change and 1 = severe change. Other colour changes such as hue change (bluer, greener, yellower etc.) are also assessed at this time. The composite slab tested has a colourfastness to light rating of 6-7, with no hue change or loss of gloss. Although no published specification is available, it is generally accepted that a rating of 6-7 indicates excellent performance in this property.

Example 3: Composite slab satisfies fire hazard safety testing. The composite slab had its fire hazard properties tested under Australian/NZ Standard AS/NZS 1530.3:1999. Specification C1.10 of the National Construction Code 2019 details the "Deemed to Satisfy" provisions in relation to fire hazard properties of linings, materials and assemblies in Class 2-9 Buildings. Table 1 states "Attachments to internal walls and ceilings" and also "Other materials including insulation" must comply with Clause 7 of this specification. Clause 7 requires materials and assemblies in Class 2-9 buildings but not included in Clause 3,4,5,6 to be tested in accordance with AS/NZS 1530.3:1999, and

"must not exceed the indices set out in Table 4". The required indices are dependent on the end use and location of the product. Information on details of the National Construction Code can be located at: https://ncc.abcb.qov.au/.

Table 1: Fire safety results Test Score Safe regulated range Ignitability index 10 Range 0-20 Spread of flame index 3 Range 0-10 Heat evolved index 4 Range 0-10 Smoke developed index 7 Range 0-10

The above results demonstrate that the composite slab do not exceed the safe regulated range for various fire hazard properties.

Example 4: Composite slab withstands impact The composite slab had its strength tested against impact stress. This test was developed in order to simulate repeated impacts of a heavy object to the product surface. The composite slab was subjected to a number of impacts using a rounded load of one kg on the corner, edge and surface and inspected for damage such as crazing or cracking of the substrate, or any cracking and peeling (delamination) of any surface finish. No change to the composite slab was observed after this testing.

Example 5: Composite slab demonstrates good scrub abrasion resistance The composite slab had its resistance to scrub abrasion tested in order to simulate cleaning by rubbing a scour repeatedly over the surface of the composite slab. The test determined that only slight scuffing of the surface of the composite slab after 3000 rub cycles, 37 cycles per minute over 250mm length using a domestic heavy duty scourer. The observation of slight scuffing indicates a rating of "Good", see table below.

Table 2: Observation rating for scrub abrasion Rating Observation Excellent No perceptible change on product surface

Good Slight scuffing on product surface Poor Significant abrasion of the product surface

Example 6: Composite slab demonstrates good resistance to heat This test was developed in order to simulate the effect of placing hot items directly onto the surface of the composite slab. A metal pot was heated to 200°C, then placed directly onto the composite slab surface for 5 seconds. After cooling the product was visually assessed for any cracking, stickiness or scorching. The pot was re-heated to 200°C and placed onto the composite slab surface for a further 5 minutes. Once cooled the composite slab was assessed for damage. The test determined that while no damage was observed after 5 seconds, slight discolouration was observed after 5 minutes under heat (see Figure 3). No physical damage such as cracking or stickiness of the surface of the composite slab was noted.

It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the above-described embodiments, without departing from the broad general scope of the present disclosure. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

Claims

CLAIMS:

1. A composite slab comprising: a) about 65% to about 95% (w/w) of milled recycled glass; and b) about 5% to about 35% (w/w) of a cured polyester resin, wherein the average particle size of the milled recycled glass is about 0.01 pm to about 100 pm.

2. A composite slab consisting of: a) about 65% to about 95% (w/w) of milled recycled glass; b) about 5% to about 35% (w/w) of a cured polyester resin; c) optionally 0% to about 1% crystalline silica; and c) optionally 0% to about 10% of one or more non-crystalline additives selected from a wetting agent, a dye, a pigment, and a filler, wherein the average particle size of the milled recycled glass is about 0.01 pm to about 100 pm.

3. A composite slab comprising a cured reaction product of: a) about 65% to about 95% (w/w) of milled recycled glass; and b) about 5% to about 35% (w/w) of a polyester resin, wherein the average particle size of the milled recycled glass is about 0.01 pm to about 100 pm.

4. The composite slab according to any one of claims 1 to 3, wherein the milled recycled glass is uniformly dispersed throughout the slab.

5. The composite slab according to any one of claims 1 to 4, wherein the composite slab is a bench-top.

6. The composite slab according to any one of claims 1 to 5, wherein the average particle size of the milled recycled glass is about 0.1 pm to about 1 pm.

7. The composite slab according to any one of claims 1 to 6, wherein the composite slab comprises about 80% to about 90% (w/w) milled recycled glass.

8. The composite slab according to any one of claims 1 to 7, wherein the composite slab comprises about 10% to about 20% (w/w) polyester resin.

9. The composite slab according to any one of claims 1 to 8, wherein the ratio of milled recycled glass to polyester resin is about 1:1 to about 20:1.

10. The composite slab according to any one of claims 1 to 9, wherein the ratio of milled recycled glass to polymeric resin is about 4:1 to about 10:1.

11. The composite slab according to any one of claims 1 to 10, wherein the composite slab comprises less than about 1% crystalline silica.

12. The composite slab according to any one of claims 1 to 11, wherein the porosity of the composite slab is less than about 0.01.

13. A process for preparing a composite slab, comprising the step of: a) curing a mixture of milled recycled glass and a polyester resin in a die to form a composite slab, wherein the curing is at a temperature of about 50°C to about 300°C and at a pressure of about 200 tonnes/m 2 to about 700 tonnes/m 2 .

14. The process according to claim 13, wherein the process further comprises the step of al) mixing the milled recycled glass and polyester resin to form a uniform mixture of milled recycled glass resin prior to the curing at step a).

15. The process according to claim 14, wherein an initiator is added to the mixture at step al).

16. The process according to claim 15, where in the initiator is a peroxide.

17. The process according to claim 15 or claim 16, wherein the milled recycled glass resin mixture at step al) is mixed for about 1 minute to about 30 minutes prior to the curing at step a).

18. The process according to any one of claims 13 to 17, wherein a release agent is applied to the surface of the die prior to the curing at step a).

19. The process according to any one of claims 13 to 18, wherein the curing is at a temperature of about 70°C and at a pressure of about 400 tonnes/m 2

. 20. The process according to any one of claims 13 to 19, wherein the curing is for a period of time of about 20 minutes to about 120 minutes.

21. The process according to any one of claims 13 to 20, wherein the mixture comprises about 65% to about 95% (w/w) milled recycled glass.

22. The process according to any one of claims 13 to 21, wherein the mixture comprises about 80% to about 90% (w/w) milled recycled glass.

23. The process according to any one of claims 13 to 22, wherein the mixture comprises about 5% to about 35% (w/w) polyester resin.

24. The process according to any one of claims 13 to 23, wherein the average particle size of the milled recycled glass is about 0.01 pm to about 100 pm.

25. The process according to any one of claims 13 to 24, wherein the average particle size of the milled recycled glass is about 0.1 pm to about 1 pm.

26. The process according to any one of claims 13 to 25, wherein the ratio of milled recycled glass to polyester resin is about 1:1 to about 20:1.

27. The process according to any one of claims 13 to 26, wherein the ratio of milled recycled glass to polyester is about 4:1 to about 10:1.

28. The process according to any one of claims 13 to 27, wherein the mixture at step a) or al) further comprises one or more non-crystalline additives selected from a wetting agent, a dye, a pigment, and a filler.

29. The process according to any one of claims 13 to 28, wherein the composite slab comprises less than about 1% crystalline silica.

30. The process according to any one of claims 13 to 29, wherein the porosity of the composite slab is less than about 0.01.