THEREFOR

Field of the Invention

The present invention relates to a coated laminate material and methods of fabricating a coated laminate material and articles of manufacture comprising the coated laminate material.

Background of the Invention

Laminate materials are commonly used in the fabrication of cabinets, doors, panels and so forth. For decorative purposes, it is often desirable to introduce a gloss finish to an exposed surface of the laminate material.

A gloss finish may be obtained by coating the laminate material with a liquid polymeric coating formulation which subsequently cures to a thin film polymeric material with a high gloss finish.

Different levels of gloss with wet paint can be achieved with subsequent processing steps combining additional layers of paint followed by sanding after each layer to achieve a suitable "dry film build" to allow final processing options to optimise the surface aspect.

Depending on the type of process system, this can be a time-consuming operation which includes sufficiently long periods between applications to allow proper curing.

Additionally, to achieve the optimum surface results, the application of liquid polymeric coating formulations are best suited to horizontal processing.

It is known to apply powder coatings to metal surfaces, to create a hard and durable finish. Powder coatings differ from liquid coating formulations in that the powder coating is a 100% solid system. The powder coating is typically applied electrostatically to the surface and is then heated to a temperature to allow melting, flowing and curing of the coating.

Powder coatings have several advantages over conventional liquid coatings including: they contain no volatile organic compounds (VOCs); they are non toxic- film thicknesses can be greater in a single process layer;

there are fewer differences in appearance between coated vertical surfaces and coated horizontal surfaces ;

there is no need for post curing;

their use results in generally shorter process times; and

there can be up to 98% utilisation of powder paint material .

However, most laminated materials are heat sensitive substrates so standard powder coatings have failed due the high processing temperatures

The present invention seeks to overcome at least some of the aforesaid problems. Summary of the Invention

In accordance with a first aspect of the present

invention, there is provided a method of fabricating a coated laminate material, the method comprising the steps of:

a) providing a laminate material comprising a substrate bonded to a laminate sheet;

b) applying a powder coating material of a polymeric material to a surface of the laminate sheet;

c) melting the powder coating material to form a film of polymeric material on the surface of the laminate sheet; and

d) curing the film with high energy electromagnetic radiation.

Melting the powder coating material may comprise heating the powder coating material to at least a temperature at which the powder coating material melts (i.e. to a temperature at or above the melting point of the powder coating material) . In one embodiment, melting the powder coating comprises applying infrared (IR) radiation to the powder coating material. In an alternative embodiment, melting the powder coating comprise heating the powder coating material, or a combination of both. Heating the powder coating material may comprise hot air heating.

The laminate material may be heated prior to applying the powder coating material.

In one embodiment of the invention, the melting step is performed at a temperature below a threshold temperature. The term 'threshold temperature' as used herein refers to a temperature at which the substrate or the laminate sheet would deteriorate, for example by warping or cracking. In general, for a substrate formed from medium density fibre (MDF) the threshold temperature is a temperature above 80°C.

In one embodiment, the powder coating material comprises a powder coating material which is capable of being cured when irradiated with high energy electromagnetic

radiation, such as UV light. In a preferred embodiment, the step of curing the film comprises irradiating the film with high energy electromagnetic radiation substantially within the UV spectrum. The wavelength of the

electromagnetic radiation may range from 100 to 445 nm.

In accordance with a second aspect of the present

invention, there is provided a method of forming an article of manufacture comprising a coated laminate material, the method comprising the steps of:

providing a coated laminate material by the method of the first aspect; and

cutting the coated laminate material to a desired size . In accordance with a third aspect of the present

invention, there is provided a method of forming an article of manufacture comprising a coated laminate material, the method comprising the steps of:

providing a coated laminate material in accordance with the method of the first aspect of the present invention; and

edge banding the coated laminate material. For each of the preceding aspects, the method may further comprise the step of mechanically treating, such as by abrading and/or polishing, a coated surface of the coated laminate material. In this way, any defects or unevenness in the coated surface may be removed by abrading the coated surface of the coated laminate material.

Additionally, a gloss finish with desirable surface qualities on the coated laminate material may be readily obtained.

It will be appreciated that abrading and/or polishing the coated surface of the coated laminate material may be performed prior to cutting or edge banding the coated laminate material.

In accordance with a fourth aspect of the present

invention, there is provided a method of making an article of manufacture, the method comprising:

forming a coated laminate material by the method of any one of the preceding aspects; and

fabricating the coated laminate material into the article of manufacture.

In accordance with a fifth aspect of the present

invention, there is provided a system for coating a laminate material with a polymeric material, the laminate material comprising a substrate bonded to a laminate sheet, the system comprising:

an application system for applying a powder coating of a polymeric material to the laminate sheet;

a heater for melting the powder coating material to form a film of the polymeric material; and a radiation source for irradiating and curing the film.

The heater may be any appropriate device capable of producing infrared (IR) radiation or convection heat or a combination of the two such as, but not limited to, electric infra red, gas catalytic IR; gas generated convection heat; and electric generated convection heat. It will be appreciated that any other appropriate means of producing heat may be used to melt the powder coating material .

The system may further comprise a cutting device or cutting apparatus for cutting the coated laminate

material.

The system may further comprise an edge banding device or apparatus for edge banding the coated laminate material. The system may further comprise a mechanical treatment device or apparatus for mechanically treating the coated laminate material. The mechanical treatment device or apparatus may be adapted for abrading and/or polishing the coated surface of the coated laminate material.

In accordance with a sixth aspect of the present

invention, there is provided a composite material

comprising a substrate bonded to a laminate sheet, and a polymeric coating disposed on an opposing/exposed side of the laminate sheet. Brief Description of the Drawings

Embodiments of the present invention will now be

described, by way of example only, with reference to the accompanying drawings in which:

Figure 1 is a schematic diagram of a method of fabricating a coated laminate material;

Figure 2 is an isometric view of a laminate material;

Figure 3 is an isometric view of a laminate material coated with a polymeric material in accordance with one embodiment of the present invention;

Figure 4 is an isometric view of the coated laminate material of Figure 3 with an edge strip applied thereto;

Figure 5 is an isometric view of the coated laminate material of Figure 4 after undergoing mechanical treatment to abrade the coated surface thereof; and

Figure 6 is a schematic diagram showing a system for fabricating an article of manufacture from a coated laminate material in accordance with an embodiment of the present invention.

Detailed Description

Specific embodiments of the present invention are now described with reference to Figures 1 to 7 in relation to a method of fabricating a coated laminate material, a coated laminate material, a method of fabricating an article of manufacture from a coated laminate material and a system for fabricating an article of manufacture from a coated laminate material . In its broadest aspect, the invention relates to a method 10 of fabricating a coated laminate material. The method comprises a first step 12 of providing the laminate material, the laminate material comprising a substrate bonded to a laminate sheet. In a second step 14, a powder coating material of a polymeric material is applied to a surface of the laminate sheet. The method comprises a third step 16 of melting the powder coating material to form a film of polymeric material on the surface of the laminate sheet. The film is then cured with high energy electromagnetic radiation in a fourth step 18.

Laminate material

Any laminate material which is suitable for fabricating substantially flat panel building materials or articles of manufacture may be employed in the present invention.

Illustrative examples of suitable laminate materials include, but are not limited to, high pressure decorative laminate (HPDL) of which commonly available examples are Formica®, Pionte®, Wilsonart®, Laminex® and Formex®; low pressure decorative laminate (LPDL) ; melamine; sealed medium density fibreboard (MDF) ; Gyprock®; and paper foil.

Referring to Figure 2, the laminate material 29 comprises a substrate 32 bonded to a laminate sheet 34.

Illustrative examples of suitable substrates 32 include, but are not limited to, plywood, fibreboard such as MDF, particle board, compressed cardboard, compressed paper, or gypsum sheet. The laminate sheet 34 may include, but not be limited to, a phenolic or an epoxy resin sheet, or a polymeric foil . The laminate sheet 34 may be bonded to the substrate 32 by physical and/or chemical adhesive means. For example, the laminate sheet 34 is bonded to the substrate 32 in HPDL by an adhesive which is applied under heat and pressure of more than 5 psi (34 kPa) .

An exposed surface 35 of the laminate sheet 34 may present a wide variety of gloss finishes and degrees of roughness which may be commonly referred to as ^lint' , ^ine texture', ^atin' and Smooth'.

Further, it will be appreciated that some types of laminate materials and/or powder coating materials may require certain techniques to improve the adhesion between the exposed surface 35 of the laminate sheet 34 and the powder coating material. In one embodiment, according to the DIN Standard DIN53151, the adhesion between the powder coating material and the laminate sheet is between Gt 0/5 B and Gt 2/3 B. Pre-treating the laminate material

Prior to the step of applying 14 the powder coating material to the exposed surface of the laminate sheet, the laminate sheet may undergo a pre-treatment process to remove oil, soil, grease and any other residual

contamination from the laminate sheet and to prepare the surface for application of the powder coating material to ensure even distribution of the powder coating material and good adherence thereto.

Pre-treatment may be performed by a variety of chemical and mechanical means. The selection of the pre-treatment depends on the type of laminate sheet which is to be powder coated, and the desired finish of the final product . Chemical pre-treatment may involve several steps to achieve optimal performance of the powder coating. A chemical pre-treatment may clean and improve the adhesion of the powder coating material to the laminate sheet. Alternatively, or additionally, the laminate sheet may undergo physical pre-treatment such as abrading the surface of the laminate sheet. Abrading may take the form of abrasive blasting, sandblasting, or shot blasting.

Blast media and blasting abrasives may be used to provide surface texturing and preparation, etching, finishing and degreasing. The form and degree of abrading will depend on the chemical composition and density of the laminate sheet, its impact resistance, the particle shape and size of the abrading media, and the desired surface finish.

Before applying 14 the powder coating material, the laminate material may also be pre-heated to enhance uniform powder application to the exposed surface of the laminate sheet. It will be appreciated that the laminate material should not be pre-heated above a threshold temperature at which the laminate material would

deteriorate, for example by warping or cracking. Powder Coating Material

Illustrative examples of suitable powder coating materials include, but are not limited to, polyesters,

polyurethanes , polyester-epoxys (known as hybrid), straight epoxy (Fusion bonded epoxy) and acrylics.

In particular the powder coating material should be one which is curable by irradiating the powder coating material with high energy electromagnetic radiation.

Examples of suitable UV curing powder coating materials that can be used in the process are systems that contain as a binder unsaturated resins (unsaturated

(meth) acrylated resins, unsaturated allyl resins,

unsaturated vinyl resins), acrylated epoxies, acrylated aliphatic or aromatic urethane oligomers, acrylated polyester or acrylic oligomers, and semi-crystalline or amorphous polyesters. For most UV curing coating

compositions the incorporation of a photoinitiator is usually preferred. Radical initiators (such as peroxides, azo-bis-isobutyronitryl, etc.), flow agents, defoamers, wetting agents, slip aids and other coating additives can be added to the powder coating formulation to improve its performance .

Further, the powder coating material may be selected such that a gloss finish can be achieved regardless of the roughness of the upper surface 35 of the laminate sheet 34, including laminate roughness levels commonly referred to as ^lint' , ^ine texture', 'satin' and Smooth'. Applying the Powder Coating Material Applying 14 the powder coating material to an exposed surface 35 of the laminate material 29 may be achieved by any known suitable process including, but not limited to, spraying with an electrostatic gun, or a tribo gun. The powder coating material may also be applied 14 by

specifically adapted electrostatic discs, the fluidized bed method, the electrostatic fluidized bed method, or by an electrostatic magnetic brush. Advantageously, the powder coating material may be applied 14 to the laminate material to produce a film of

substantially even thickness, in any desired orientation, including vertically, horizontally, and any angle

therebetween. The versatility in orientation of the laminate material is particularly convenient for forming a coating with a high gloss finish on curved surfaces, such as roll-formed edges which are often desirable for benchtops and cabinetry. Melting the Powder Coating Material

The step of melting 16 the applied powder coating material comprises heating the powder coating material to a temperature at or above a temperature at which the powder coating material melts (ie. to a temperature at or above the melting point of the powder coating material) , flows over the surface of the laminate sheet and forms a film. In one embodiment, melting 16 the powder coating comprises applying infrared (IR) radiation to the powder coating material. In an alternative embodiment, melting 16 the powder coating comprises convection heating the powder coating material. In a further alternative, melting 16 the powder coating material comprises a combination of both applying IR radiation and convection heating.

Suitable heating means to heat the powder coating material include, either individually or in combination: infrared lamps; gas catalytic infrared; gas generated convection heating; and electric generated convection heating. Any other appropriate means for melting 16 the powder coating may be used.

Curing the Powder Coating Material

Curing 18 the powder coating material may comprise irradiating the resulting film of polymeric material with high energy electromagnetic radiation, preferably UV radiation within a wavelength range of 100 nm to 445 nm.

Curing 18 the powder coating material should be conducted at a temperature where the laminate substrate 29 is not damaged. This is conveniently achieved by using UV radiation .

Any suitable means for irradiating the film of polymeric material with high energy electromagnetic radiation may be employed.

Coated laminate material

Once the powder coating material is fully cured the coated laminate material 30 comprises a substrate 32 bonded to a laminate sheet 34, and a polymeric coating 36 disposed on exposed side 35 of the laminate sheet 34, as illustrated in Figure 3. The final film build of the polymeric coating 36 is dependent on the substrate and the desired finish. The final film build may have a thickness in a range of 80 - 250 μπι. The powder coating material may be selected to provide a wide range of finishes such as matt (smooth and texture) , satin (Smooth and texture) and gloss. High gloss finishes can be value added by sanding and polishing to produce a 'piano' gloss finish (no orange peel) on the coated laminate material 30. In the above examples, the term

^igh gloss' finish refers to a surface finish having a relatively high gloss value with Grange peel', and

^iano' finish refers to a surface finish having a relatively high gloss value with no Grange peel' . The term Grange peel' refers to the surface roughness of the surface finish.

In another embodiment, the powder coating material is selected such that the cured layer has substantial resistance to softening due to heat caused by friction when the coated laminate material undergoes further abrading and/or polishing.

It is also desirable that the coating 36 comprises a UV cured powder coating material having a viscosity range optimised to be processed horizontally or vertically without compromising the finish (flow, gloss and sag resistance) . Advantageously, the inventors have found that the coating 36 prepared in accordance with the method of the present invention is resistant to chipping and delaminating if the coated laminate material 30 undergoes further mechanical treatment such as cutting, edge banding, and abrading and/or polishing.

Accordingly, the coated laminate material 30 of the present invention may be conveniently used to fabricate various articles of manufacture such as benchtops, cabinets, doors, panels, partitioning systems, wall surfacing, wet area wall lining, and vertical surfaces for domestic, commercial and industrial premises.

Cutting

Cutting the coated laminated material 30 may be performed using well known techniques that would be appropriate for cutting substrates such as MDF and similar materials. The cutting process may be automated, such as by using a vertical band-saw, panel saw, CNC router and conveyor system, or manually, such as by using a saw. Some prior art methods involve cutting articles to size prior to applying a coating, such as a paint coating, as some prior art coating methods result in delamination or chipping of the coating during the cutting process. Accordingly, coating an article in accordance with the method of the present invention prior to cutting provides efficiency advantages in that larger sheets of laminate materials can be coated prior to cutting, thus reducing waste handling and improving consistency between articles cut from the same sheet.

Edge Banding Referring to Figures 4 and 5, an uncoated surface 37 of the coated laminate material 30 may be edgebanded, if desired, by having an edge strip 38 applied the surface 37. Edgebanding may be performed after cutting the coated laminate material 30, and the edge strip 38 may be applied to the uncoated surface 37 formed when the coated laminate material 30 is cut.

The edge strip 38 can be applied to the uncoated surface 37 by known means such as by bonding the edge strip 38 to an edge of the coated laminate material 30 with an adhesive. The upper surface 40 of the coating 36 may be later abraded so that the upper surfaces 40, 42 are at substantially the same height, as shown in Figure 5.

During edge banding, it is common for damage to occur to the upper surface 40 of the coating 36. This may be caused, for example, by the conveyor and other alignment and clamping methods. Abrading and polishing the surface 40 after edge banding provides the advantage that any surface defects caused by handling, cutting, machining and edge banding can be removed with abrading and polishing processes . Abrading

Referring to Figure 4, the coated laminate material 30 is shown with an edge strip 38 applied to the uncoated surface 37 of the coated laminate material 30. In this embodiment, the upper surface 40 of the coating 36 is at a similar height to upper surface 42 of the edge strip 38. The upper surface 40 of the coating 36, and the upper surface 42 of the edge strip 38 can then be abraded using conventional means. This may have a number of advantageous effects. The height of the coating 36 will be level with the upper surface 42 of the edge strip 38, and a

substantially smooth transition between the upper surfaces 40, 42 can be formed. Further, abrading can remove surface defects that may have been caused by earlier processing steps .

Figure 5 shows the composite material 30 after the coating 36 has been sanded such that the upper surfaces 40, 42 of the coating 36 and edge strip 38 respectively are at substantially the same height.

It will be appreciated that the coating 36 may be abraded by any conventional means across its surface, in its entirety or in part, as desired.

Polishing After abrading, the coated laminate material 30 may be polished using traditional manual technigues or automated procedures using flat bed polishing equipment to produce a range of gloss finishes. It will be appreciated that other finishes may be further applied to the coating 36.

It will also be appreciated that after undergoing cutting, edgebanding, abrading, polishing or any other mechanical treatment as desired, the coated laminate material 30 may be fabricated into any suitable article of manufacture such as benchtops, cabinets, doors, panels, partitioning systems, wall surfacing, wet area wall lining, and vertical surfaces for domestic, commercial and industrial premises by conventional techniques such as those known to persons skilled in the art. It will be appreciated that the method of fabricating an article of manufacture does not necessarily have to follow each of the steps described. For example, the article may already be cut to size or edge banding may not be

necessary or desirable.

Further, it will be appreciated that the method 10 may result in the production of sheets of the coated laminate material 30 wherein any desired cutting and/or edge banding is performed by a third party so as to produce further articles of manufacture.

Using the above described method to produce composite material 30 shown in Figure 5, has the advantage that uncut sheets of material may be processed so as to achieve better productivity, for example by acquiring less material handling. Further, more consistent coatings may result as a single sheet is treated as opposed to

individual components which may otherwise introduce unnecessary variation in the coating 36 during the coating process.

A System for Fabricating an Article of Manufacture

Figure 6 shows a system 44 that can be used to fabricate an article of manufacture, such as a kitchen door. The system 44 may be implemented as a series of workshop modules that can be used to perform the steps of the above described method. The system 44 may share some components between these modules, such as conveyor systems, or may in fact be the same module modified in some way so as to perform the necessary function. Although the system 44 is described below as comprising modules for conducting the steps of applying the powder coating material and onwards, it will be appreciated that the system 44 may comprise further modules for conducting the pre-treatment process. For example, the system 44 may further comprise a mechanical cleaning module for cleaning the surface of the laminate material 29, a chemical pre- treatment module for cleaning the surface of the laminate material 29 and for improving the adhesion of the powder coating material to the laminate material 29, and a pre- heating module for pre-heating the surface of the laminate material 29 prior to application of the powder coating material .

In this example, the system 44 comprises an applicator 46 for applying the powder coating material to the laminate material 29. The applicator 46 can be arranged to allow the laminate material 29 to be arranged in different orientations. For example, the applicator 46 can be arranged to allow the powder coating material to be applied to the laminate material 29 when the laminate material is in a horizontal or a vertical orientation. Further, the applicator 46 may be arranged to allow the powder coating material to be applied to a plurality of laminated surfaces of the laminate material 29.

The system 44 also comprises a heater 48 for melting the powder coating that has been applied by applicator 46 to the laminate material 29. The heater 48 can be any appropriate device capable of producing heat such as, but not limited to gas catalytic IR; gas generated convection heat; and electric generated convection heat. Any

appropriate heating means may be used.

The heater 48 is arranged to heat the powder coated laminated substrate below the threshold temperature so as to avoid unnecessary damage to the laminate material. The system further comprises a radiation source 50 for irradiating the coated laminate material after the powder coating material has been melted. The radiation source 50 may be any appropriate radiation source for curing powder coatings, particularly powder coatings that are curable by UV radiation. For example, the radiation source may produce electromagnetic radiation having a wavelength between lOOnm and 445nm.

The system 44 further comprises a cutting system 52 for cutting the coated laminate material to a desired size.

For example, the cutting system 52 may be a vertical band- saw and conveyor system arranged to cut the coated laminate material in an automated fashion. The system 44 further comprises an edge banding system 54 for applying an edge strip 38 to an uncoated surface 37 of the coated laminate material. The edge banding system 54 is arranged to apply an adhesive to at least one of the uncoated surface or an engaging surface of the edge strip 38 and to apply the edge strip 38 to the uncoated surface 37 such that the uncoated surface 37 and edge strip 38 bond to one another. The edge banding system 54 may be arranged to affix the edge strip 38 to the uncoated surface 37 in any other appropriate manner, such as by applying fastening means like nails or screws.

The edge banding system 54 is arranged to apply the edge strip 38.

The system 44 further comprises a sander 56 for abrading the upper surface 40 of the coating 36. The sander 56 may be any conventional type of sanding device system, and is arranged to level the coating 36 and to remove any surface defects that may have been caused by any of the preceding system components. The sander 56 can be arranged to reduce the height of the coating 36 to a level such that there is a substantially smooth transition between the upper surface 40 of the coating 36 and the upper surface 42 of the edge strip 38.

The system 44 further comprises a polisher 58 for

polishing the upper surface 40 of the coating 36. The polisher 58 may be any standard polishing device or system, and is arranged to polish the surface 40 so as to obtain a high gloss finish.

It will be appreciated that the system 44 may not

necessarily comprise the cutting system 52 and/or the edge banding system 54. The system 44 may produce sheets of the coated laminate material 30, and any desired cutting and/or edge banding can be performed by a third party so as to form further articles of manufacture.

Numerous variations and modifications will suggest themselves to persons skilled in the relevant art, in addition to those already described, without departing from the basic inventive concepts. All such variations and modifications are to be considered within the scope of the present invention, the nature of which is to be determined from the foregoing description.

In the claims which follow and in the preceding

description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.