AU2012101047A4 - Treatment of radiata pine - Google Patents

Abstract

Abstract The invention relates to methods of processing Radiata Pine timber and to Radiata timber products. In particular, the invention relates to methods and Radiata products that mimic the aesthetic and stability characteristics of more expensive and less environmentally sustainable timber species.

Description

0o4 29AUPR TREATMENT OF RADIATA PINE TECHNICAL FIELD 5 The invention relates to methods of processing Radiata Pine timber and to timber processed by that method. BACKGROUND ART 0 Radiata Pine ("Radiata") is the most important commercial species of timber used in New Zealand and Australia. It is used in a number of exterior construction applications such as structural members (for example, weight bearers and joists), decking and cladding. However, unlike other types of timber, Radiata has a number of inherent disadvantages, including lack of stability in service, surface checking and poor colour/aesthetics following exposure, which have 5 resulted in Radiata being unable to compete in some market applications with higher-priced timbers such as Western Red Cedar for cladding and hardwoods and Kwila (also known as Merbau), for decking. Consequently, Radiata is simply viewed as a commodity material for decking and cladding applications. o When used for decking applications, Radiata is often supplied in a form known as "wet, treated" which is very prone to shrinkage as the moisture content of the timber equilibrates to the surrounding conditions. This shrinkage results in unsightly dimensional changes. Furthermore, Radiata is not perceived to have pleasing aesthetics in its natural state. However, painting to overcome the lack of aesthetics is not practical for decking applications. Coatings and stains 25 can be applied but these add cost and inconvenience. As a result of these disadvantages, Radiata Pine in a "wet, treated" format is not considered a premium decking material and is often seen as a cheap decking option by the market. The predominant premium timber species used for decking in New Zealand is Kwila, which has a pleasing dark colour and is stable in service. 30 In cladding applications Radiata is always painted, typically with lighter colours. Painting not only results in a better surface finish, but it also ensures increased stability of the timber and also enhances its aesthetic appeal. This is because, if it is not painted, the Radiata used for cladding, like the "wet, treated" timber in decking applications, is not always stable and has a 0o4 29AUPR -2 propensity to distort (or "warp") and surface check when exposed to a range of varying climatic conditions. Use of Radiata in cladding and decking applications does, however, have some advantages, 5 particularly over the hardwoods. These advantages typically relate to cost and to environmental concerns. For example, hardwood species are often slow growing and exist within naturally occurring tropical forests resulting in environmental concerns amongst the general public. By comparison, Radiata is grown as a plantation species which is quick growing, continually re forested and, as such, sustainably grown. Radiata is also readily available in New Zealand and 0 elsewhere. The rapid growth rate of Radiata compared to hardwoods means the trees can be harvested earlier and this, along with its ready availability, leads to cost benefits. In addition, prices of many hardwood species are increasing around the world due to their declining availability. 5 The use of preservatives and modification techniques are known to provide means for increasing the durability of soft woods such as Radiata. These techniques are well known and provide options individually or together in combination to increase the durability of soft woods such as Radiata. o To improve the stability of Radiata, it is known to laminate individual boards together. It is known in the art that boards with a vertical grain orientation are more resistant to warping, splitting and surface checking and are thus more stable when used. Laminated wooden boards are typically produced by gluing together individual boards in a flat grain orientation edge to edge or face to face to give individual finished boards with a flat or mixed grain orientation. 25 However, lamination in this way typically results in finished boards of flat or mixed grain orientation that are more prone to surface checking and movement. It also results in unsightly glue lines in the finished product. Clear glue, or glue tinted to substantially match the final timber can mitigate this, but does not always sufficiently meet customer quality requirements. To hide the appearance of such lines, the laminated wooden boards are often painted, or 30 alternatively, striations can be cut into the surface of the wooden boards. Such striations are typically spaced such that they lie along the glue lines such that they serve to camouflage them. An example of such lamination techniques is shown in NZ 562263 to Lockwood Buildings Limited. As can be seen in this patent, striations of more than 1 mm in width are cut into the 35 laminated timber parallel to the glue lines to hide the lines in the final product. A wider laminate 0o4 29AUPR -3 is used in the profiled section so that a glue line does not appear in that part of the laminate board when in place. However, striations of greater than 1 mm limit the usefulness of laminate Radiata boards as not all applications suit such an appearance. 5 It is an object of the present invention to provide a method for processing Radiata timber to enhance the stability and/or aesthetic characteristics of the timber, or at least to provide the public with a useful choice. SUMMARY OF THE INVENTION 0 In a first aspect the present invention provides a method of processing Radiata timber to enhance the stability and aesthetic characteristics of the timber, the method comprising the steps of a. applying a preservative; 5 b. colouring the timber throughout its cross-section, c. lamination with a colourless or tinted glue to produce a vertical grain orientation on the face of the board; and d. surface finishing comprising the addition of one or more striations to the surface of the timber. 0 Colouring the timber can be achieved by: (i) thermal modification; (ii) furfyl modification; (iii) resin impregnation; 25 (iv) use of a colourant; (v) use of a preservative that has an inherent colour due to its chemistry e.g. ACQ Preferably, if a colourant is used it is applied concurrently with the preservative. Preferably, if thermal modification is used it is carried out prior to applying the preservative and lamination. It is very much preferred that the surface finishing comprises the addition of striations of less 30 than 1 mm width. In a further embodiment, the timber may undergo treatments to increase surface hardness, stability and/or durability. Exemplary treatments include furfyl modification and resin impregnation. 35 0o4 29AUPR -4 In a particular embodiment, the timber is produced from boards originally cut from a tree in a substantially flat grain orientation, wherein said boards are laminated together by gluing before being cut substantially perpendicular to the grain to produce individual boards with what appears to be a substantially vertical grain orientation. 5 Preferably the colourant is a pigment or a dye and preferably naturally occurring as opposed to chemically synthesized. Preferably the solvent-based preservative is azole-based (e.g. tebuconazole, propiconazole) or 0 copper napthenate. Preferably the water-based preservative is ACQ, copper azole, or azole-based (e.g. tebuconazole, propiconazole). 5 Preferably the surface of the Radiata timber is finished using striations that are produced by: (i) a band-sawn effect applied during band sawing of the laminated block into individual boards (ii) a micro-reed effect applied during profiling of the boards in a timber planar operation (iii) a brushed effect using a brushing tool. Preferably, the brushing tool is a metallic 0 brushing tool that is a stand-alone piece of equipment or has been adapted to be used in a stand-alone timber planar operation. In a second aspect the present invention provides a method of processing Radiata timber to enhance the stability and aesthetic characteristics of the timber, the method comprising the 25 steps of a. applying a preservative; and b. lamination with a colourless or tinted glue; and c. surface finishing; and d. colouring the surface of the timber in final form through addition of a colourant (also 30 known as a tint) in a water-based coating, prior to installation ("pre-coating"). Preferably the colourant is a pigment or a dye and preferably naturally occurring as opposed to chemically synthesized.

0o4 29AUPR Preferably the solvent-based preservative is azole-based (e.g. tebuconazole, propiconazole) or copper napthenate. Preferably the water-based preservative is ACQ, copper azole, or azole-based (e.g. 5 tebuconazole, propiconazole). Preferably the surface of the Radiata timber is finished using striations that are produced by: (i) a band-sawn effect applied during band sawing of the laminated block into individual boards 0 (ii) a micro-reed effect applied during profiling of the boards in a timber planar operation (iii) a brushed effect using a metallic brushing tool that is a stand alone piece of equipment or has been adapted to be used in a stand alone timber planar operation. Preferably the striations are less than 2.5 mm in width, more preferably less than 1 mm. 5 In a further aspect, the invention provides a laminated timber product produced by any one or more of the above methods. In a further aspect, the invention provides a laminated Radiata timber product wherein 0 the surface of the timber has a surface finish comprising striations to disguise one or more glue lines from the lamination process; and wherein the timber is coloured to mimic the colour of a different wood; and wherein the timber is treated with a preservative. 25 The invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, in any or all combinations of two or more of said parts, elements or features. Further aspects of the invention, which should be considered in all its novel aspects, will 30 become apparent to those skilled in the art upon reading of the following description which provides at least one example of a practical application of the invention. DESCRIPTION OF THE FIGURES Embodiments of the invention will now be described, by way of example only, with reference to 35 the accompanying drawings in which: 0o4 29AUPR -6 Figures 1 to 4 show the appearance of laminated Radiata Pine boards prepared according to the processes of the invention after brushing. 5 Figures 5 to 8 show the appearance of laminated Radiata Pine boards prepared according to the processes of the invention with a band sawn finish. DETAILED DESCRIPTION 0 The present invention is directed to a method for processing Radiata Pine timber to alter the stability and aesthetic characteristics of the timber. In particular, the invention allows the processed timber to be coloured and to undergo lamination with surface treatment capable of resulting in striations of less than 1 mm in width to camouflage the lamination glue lines, and also to mimic Western Red Cedar, Kwila, Teak, Vitex, Ipe, Balau and/or Bankirai. The 5 processed timber can therefore be used in outdoor applications, such as decking or cladding, in place of these species of timber. It would be an advantage to provide a laminate Radiata Pine board that was able to have striations of less than 1 mm to provide a suitable aesthetic appearance. The process could be 0 used to provide wider striations if desired, but preferably of no more than about 2.5 mm in width, to disguise the lamination glue lines in the laminated board. In addition, it would be useful for the laminated Radiata Pine product to be able to mimic the look of species including Western Red Cedar, Kwila, Teak, Vitex, Ipe, Balau, Bankirai or other commonly used timbers, when supplied for appropriate applications. It has been found that the use of striations of 1 mm or 25 less, when used in conjunction with the other steps of the invention, provides a surprisingly effective mimicking effect to be produced. Such an effect provides an advantage to the users of the present invention when using Radiata in similar applications to other species of timber, such as those described above. 30 The combination of mimicking the look of the above mentioned species of hardwood and allowing the use of striations of less than 1mm to camouflage the lamination glue lines, would provide particular advantages to the user and to the wider environment. An essential step in one method of the present invention involves the colouring of the timber 35 throughout its whole cross section with a desirable market colour. Among other methods, this 0o4 29AUPR -7 can be done by (1) thermal modification at a selected end point temperature to give the desired colour or (2) by use of a chemical colourant that is added during the preservative treatment process, which is required for all Radiata boards to be used in exterior applications. Other methods include furfylation and resin impregnation. It is also possible to use a preservative 5 having inherent colour due to its chemistry. In particular, having colour throughout means that if the timber needs to be sanded back for remediation work, the colour will be the same as the method of this preferred option of the present invention is not a surface finish only. This remediation ability provides a particular benefit to the user. o It is known in the art that thermal modification changes the colour of timber. The end colour achieved is dependent mainly on the end-point temperature at which thermal modification is carried out. Thus, the higher the end-point temperature, the darker the wood becomes throughout. Variations in colour can be achieved by altering the end-point temperature and uniform colour throughout the timber can be achieved. The main advantage of being able to 5 control the colour is that the Radiata Pine can be made to mimic the appearance of other species of timber. This allows the end user to achieve a desired appearance for exterior applications. Further methods of treatment/modification may be used to achieve colouring and/or other 0 desirable properties such as an increase in surface hardness, stability and/or durability. Exemplary treatments include furfyl modification and resin impregnation. Resin impregnation may include using pressure to force organic or non-organic- based resins e.g. urea formaldehyde or a combination Urea and Starch-based emulsion, that will increase the 25 colour, stability, durability and/or surface hardness characteristics of pine. Colour may also be modified by using this technique. Exemplary products that may achieve one or more of these treatments include Lignia T M and EverdexTM. Furfyl modified wood undergoes a process known as furfylation which uses furfyl alchohol to 30 modify the cell structure of the wood and thereby increase surface hardness, stability and durability. Colour may also be modified by using this technique. An exemplary product that may achieve this treatment is Kebony

TM

. Thermal modification, in addition to changing the colour of the timber, also results in an increase 35 in the stability of the timber. Thermal modification is preferably carried out in a high pressure 0o4 29AUPR -8 cylinder and essentially involves a high pressure steam treatment of kiln dried Radiata timber. Any type of high pressure cylinder can be employed for this purpose and a kiln system that has been specifically designed for the elevated temperatures associated with thermal modification could also be used for the thermal modification step. Such thermal modification kilns, as offered 5 by way of example, by Tekmaheat or Stellac, would be well known to the skilled person in the area. Preferably the kiln dried timber has a moisture content of about 16% or less. The high pressure steam treatment ordinarily involves subjecting the Radiata Pine timber to temperatures above 1500C, preferably ranging between about 1500C and about 2000C. 0 Preferably, the temperature range is between about 1550C and 1850C, more preferably about 1650C. At 1650C the look of Western Red Cedar is achieved. It is worth noting that elevated temperatures do result in a decrease in structural integrity of the timber. Thus, while higher temperatures may result in a more desirable darker colour, the resultant loss of structural integrity dictates the final applications for which the timber can be used. The high pressure 5 steam treatment is preferably carried out over a period of between about 2 days and about 4 days, more preferably over 3 days to give a completely coloured and dried product (approximately 16 % moisture content). Alternatively, a shorter period of thermal modification can be used (less than 12 hours) to effect the colour change followed by traditional kiln drying to remove the moisture. As indicated above, the process of thermal modification is well known to 0 enhance the stability of Radiata Pine timber as well as impart a colour change. However, thermally modified timber still needs to be laminated to further increase its stability. The process of lamination is discussed in more detail below. The use of a chemical colourant to colour the wood throughout its whole cross-section typically 25 involves the addition of a dye or pigment to the chemical formulation when the timber is treated with a preservative treatment. The dye or a pigment is preferably naturally occurring and must be chemically compatible with the preservative treatment being used. Use of a colourant ensures a particular colour is achieved for the final wood product. The colourant, if used, will be applied concurrently with the preservative, and if desired a suitable wetting agent (surfactant 30 system) can be used to assist penetration. The preservative treatment can be either a solvent-based treatment or a water-based treatment. Examples of suitable solvent-based preservatives include, TBTN, TBTO, Copper Napthenate, tri-azoles such as 1 -[[2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl]methyl]-1,2,4-triazole 35 (Propiconazole) and (RS)-1-(4-chlorophenyl)-4,4-dimethyl-3-(1,2,4-triazole-1-yl-methyl)pentan- 0o4 29AUPR -9 3-ol (Tebuconazole) and termidicide preservatives such as 3-phenoxybenzyl-(1 RS)-cis,trans-3 (2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylate (Permethrin) and/or N-[1-[(6-chloro-3 pyridyl)methyl]-4,5-dihydroimidazole-2-yl]nitramide (Imidacloprid). Examples of suitable water based preservatives include CCA, ACQ and Copper Azole. It is also an option to use a 5 preservative that has inherent colour due to its chemistry (e.g. ACQ) if that meets colour requirements. Additional colour could be added if desired, but this may not be needed. The process of colouring the wood by use of a chemical colourant incorporated into the preservative treatment may be carried out either before or after lamination of individual boards. o Where the wood is coloured by thermal modification, the subsequent preservation step may be carried out either before or after lamination of individual boards. The order is dependent on the nature of the preservative treatment. For example, where the preservation step involves high water uptake, the timber will have to be subsequently re-dried before it can be laminated. Conversely, where the preservation step is solvent based or involves low water uptake, the 5 timber may be laminated prior to the preservative treatment being undertaken. The process of lamination in the method of the present invention involves standard techniques which would be known to a person skilled in the art. As indicated above, lamination provides enhanced stability to the timber product (which cannot be achieved by thermal modification 0 alone if this has been selected as the means to add colour throughout the timber) as well as a more aesthetically pleasing vertical grain orientation. Timber produced according to the methods of the present invention should be produced from boards originally cut from a tree in a substantially flat grain orientation. These flat-grain boards are then laminated together by gluing before ripping (cutting) substantially perpendicular to the grain to produce individual boards with 25 a substantially vertical grain orientation. It is known in the art that boards with a vertical grain orientation are more resistant to warping, splitting and surface checking and are thus more stable when used. It is important that the boards being laminated are appropriately selected and aligned or 30 arranged so that the surface of the final board has a vertical grain appearance. However, as previously stated, this results in the appearance of unsightly glue lines in the final timber product. To help mitigate this, it is preferable that a colourless glue is employed during the lamination process. Alternatively, a glue tinted to substantially match the colour of the final timber product can be employed. Examples of suitable colourless glues include polyurethanes, 35 isocyanates and melamine-urea formulations. To achieve the desired tint in the glue a suitably 0o4 29AUPR - 10 coloured dye or pigment would be added to the glue. The dye or pigment used may not necessarily be the same dye or pigment used to colour the wood as the chemistry of the wood versus the glue is different. 5 It is noteworthy that use of a colourless glue or an appropriately tinted glue alone is not enough to sufficiently mitigate the appearance of glue lines to meet customer requirements. Consequently, on completion of the lamination process, unsightly glue lines (or join lines) remain evident in the surface of the timber. In order to create a quality product, it is desirable that these glue lines are obscured or disguised (i.e. camouflaged) by a surface finishing 0 technique. One method of surface finishing appropriate to achieve the invention is the cutting of striations into the surface of the timber at predetermined intervals and depths. As previously indicated, and with reference to NZ 562263, these striations typically have a width and depth of 1 mm or more and run parallel to the glue lines such that they lie along the glue lines themselves. In NZ 562263 the problem of glue lines (or join lines) was overcome by cutting 5 striations to a width of 1 mm to 5mm into the timber surface. The pitch between adjacent striations was said to be about 3 mm and the raised surface between adjacent striation channels was said to be approximately 2 mm. Many of the striations lay along individual glue lines. o As previously discussed, the inventors have found that use of striations of less than 1mm in width has a particular advantage in allowing a mimicking of the appearance of other species of timber when used in conjunction with the other processes of the invention. The micro-reed process and brushing techniques are capable of forming striations of less than 1 25 mm in width and therefore both provide a means of producing a quality timber product with an aesthetically pleasing surface finish where the glue lines are completely camouflaged. The use of finer striations also avoids the need to ensure that individual striations lie along individual glue lines. These striations typically run parallel to the lamination glue lines. 30 The micro-reed effect is applied during profiling of the boards in a timber planar operation. The profiling is done using knives designed to cut a specific "micro-reed" pattern which comprises ridges and bumps. These knives are fitted into the profiling machine to obtain the desired surface finishing effect. Preferably, the profiling and addition of the micro-reed effect is obtained in a single operation. Preferably the ridges and bumps are of approximately 0.2-1.0mm in width 0o4 29AUPR - 11 and have a length that is longer than the width wherein the length is aligned substantially lengthwise along the board. The brushing technique is randomised in the sense that it involves the use of a metallic brushing 5 tool and results in non-uniform striations. This tool is adapted to be used in a timber planar operation such that the surface of the board contacts the brushing tool as it passes beneath it, leaving a brushed appearance on the board surface. The brushing tool can also be used as a stand alone piece of equipment. o Striations can also be applied that are largely perpendicular to the glue lines and the most common method would be to create a band sawn effect obtained during cutting with a band saw. These are less effective at directly covering the glue line, but do create a surface that is more aesthetically pleasing than the bare exposed lamination glue lines and will be desirable in some applications where a more rustic look is required. 5 The inventors have found that when the wood is coloured throughout (by either thermal modification; or use of a colourant employed in conjunction with preservation; or use of a preservative with inherent colour), laminated with a colourless or tinted glue and then profiled to give a surface finish with striations of less than 1 mm in width (such as a micro-reed, brushed or 0 band sawn appearance), a timber product is produced which not only mimics the appearance of the likes of Western Red Cedar, Kwila, Teak, Vitex, Ipe, Balau, and/or Bankirai but also shows enhanced stability characteristics approaching or equal to those of Western Red Cedar and other hardwoods and previously unobtainable for soft woods when used as a single solid board. If necessary, surfactant systems, as would be known in the art, can be used to ensure effective 25 penetration of the timber. The ability to mimic such characteristics of other species of timber using Radiata is of particular advantage. In addition, the laminated wood product can be subjected to remedial work (e.g. sanding) without loss of colour thus adding to the aesthetics and usefulness of the product. 30 Without wishing to be bound by the following comments, the inventors hypothesise that the step of colouring the wood, whether by thermal modification, addition of a colourant, by use of a preservative with inherent colour, or other colouring methods, prior to or subsequent to lamination, or by incorporating the colourant into a pre-coating of the final product, is critical to the resultant product. The subsequent use of a surface finishing technique to produce the 35 required striations on the surface of the wood, preferably band sawn processing, micro-reed 0o4 29AUPR - 12 processing or brushing techniques, results in a product which closely mimics the aesthetic and stability characteristics of hardwoods referred to herein, such as Western Red Cedar and Kwila. Therefore, Radiata Pine processed according to the method of the present invention can be used in cladding and/or decking applications in place of more expensive hardwoods as it can 5 give the appearance of a high quality timber product which has not been laminated. The final application is dependent only on the structural integrity requirements and aesthetic look the customer desires. Structural integrity requirements dictate that where thermal modification is utilised to colour the timber it can not be utilised in decking applications. With respect to aesthetic look, in cladding applications, a brushed or band sawn look is often desired. Typically, 0 the brushing technique is employed as the non-uniform appearance of multiple striations is appealing. In contrast, in decking applications, the micro-reed process will likely be more popular although the brushing look and even the band sawn look may be utilised. The surface of the Radiata timber can thus be finished using required striations that are 5 produced by: (i) a band-sawn effect applied during sawing of the laminated block into individual boards (ii) a micro-reed effect applied during profiling of the boards in a timber planar operation (iii) a brushed effect using a metallic brushing tool that is a stand alone piece of 0 equipment or has been adapted to be used in a stand alone timber planar operation. Alternative options that would be known to the skilled person could also be used. Thus, the method of the present invention provides a Radiata Pine timber product which mimics 25 the appearance of other quality timbers such as Western Red Cedar, Kwila, Teak, Vitex, Ipe, Balau and/or Bankirai has enhanced stability and is aesthetically pleasing. In another aspect the present invention also provides a method of processing Radiata timber which also enhances the stability and aesthetic characteristics of the timber in a more simplified 30 and cost effective manner. This method includes the steps of: a. applying a preservative; and lamination with a colourless or tinted glue; and b. surface finishing; and c. colouring the surface of the timber in final form through addition of a colourant (also known as a tint) in a water-based coating, prior to installation ("pre-coating"). 35 0o4 29AUPR - 13 Coatings are normally clear oil-based or water-based chemical formulations that are applied manually to timber decks or cladding post installation to act as a barrier against water and sunlight (UV) when timber is used in an exterior situation. This prevents the timber from weathering or "silvering off" and maintains the original look of the timber. Coatings are 5 transparent so that the underlying grain structure of the wood is still visible, unlike a painted timber board. Pre-coating of timber boards is undertaken in a factory setting prior to delivery and installation that allows a more uniform application. The coating is applied using purpose-designed 0 equipment such as a spray system or vacuum coater. During this process it is possible to tint or colour the coating formulation to achieve a coloured product. Coating of timber boards has limitations in that the coating (and hence the colour) is only applied to the surface and will wear off after time in service. This means re-coating in-situ will 5 be necessary if the end user wishes to maintain the look and if a similar colour is required the chemical formulation with matching colourants will need to be made available at a retail level to the end user. Nonetheless, this other aspect of the present invention is particularly useful for consumers who 0 desire a coated finish to their decking. The combination of the lamination with the stated glues, surface finishing and colourant in a water based coating being able to provide a radiata alternative to hardwood options. While the aesthetics of the timber produced are not as pronounced as in the previously discussed inventive process (as the cross section view will not show the colour extending throughout the timber used and remedial options will be more limited) 25 the final result is of sufficient quality to provide an adequate effect to achieve the timber alternative. The components of this process can be as described previously. The method is also capable of allowing surface finishing with striations with a width of less than about 2.5 mm but can also achieve less than about 1 mm as well. Use of techniques as 30 previously described, but preferably brushing, to achieve the finer striations, can be used. Products with striations of less than 1 mm as previously described provides an advantage to the user in that they effectively mimic the aesthetic qualities of other timbers including Western Red Cedar, Kwila, Teak, Vitex, Ipe, Balau and/or Bankirai. 35 0o4 29AUPR - 14 EXAMPLES Example 1: Thermally-modified, laminated, brushed Radiata pine cladding 5 Clear grade green boards of 100 mm x 25 mm were sawn from 100% sapwood and were steamed at 1650C for 4 to 6 hours. The boards were then kiln dried using conventional medium temperature kilns with a typical Radiata pine drying schedule. A preservative treatment was then carried out using a solvent-based LOSP process to H3.1 clear. The boards were blanked to 100 mm x 23 mm using a conventional planning machine and were then laminated into a 0 block with a clear polyurethane exterior-grade adhesive (Henkel Purbond) taking care to ensure the grain of each board was orientated in the flat-sawn direction. The resultant block was sliced, using a conventional band saw, into a number of nominal 150 mm x 25 mm boards that exhibited a quarter-sawn appearance. The boards were profiled using a conventional planing machine using a band sawn finish (Figures 5 to 8). The boards were then coated using a 5 vacuum coater with an Akzo Nobel, water-based polyurethane. Example 2: Preservative coloured, laminated, profiled Radiata pine decking Clear grade green boards of 150 mm x 35 mm were sawn from 100% sapwood and were kiln 0 dried using conventional medium temperature kilns with a typical Radiata pine drying schedule. The boards were then preservative treated using a water-based process with ACQ to H3.2. The treated boards were blanked to 150 mm to 32 mm using a conventional planning machine and were subsequently laminated into a block with a clear polyurethane exterior-grade adhesive (Henkel Purbond) taking care to ensure the grain of each board was orientated in the flat-sawn 25 direction. The block was sliced, using a conventional band saw, into a number of nominal 150 mm x 25 mm boards that exhibited a quarter-sawn appearance. The boards were then profiled using a conventional planing machine with attachment to brush striations of less than 1 mm in width into the surface of the boards (figures 1-4). 30 Example 3: Laminated, profiled, pre-coating coloured Radiata pine decking Clear grade green boards of 150 mm x 35 mm were sawn from 100% sapwood and were kiln dried using conventional medium temperature kilns with a typical Radiata pine drying schedule. The boards were then preservative treated using a water-based process with ACQ to H3.2. The 35 treated boards were blanked to 150 mm to 32 mm using a conventional planning machine and 0o4 29AUPR - 15 were subsequently laminated into a block with a clear polyurethane exterior-grade adhesive (Henkel Purbond) taking care to ensure the grain of each board was orientated in the flat-sawn direction. The block was sliced, using a conventional band saw, into a number of nominal 150 mm x 25 mm boards that exhibited a quarter-sawn appearance. The boards were then profiled 5 using a conventional planning machine with attachment to brush striations of less than 1 mm in width into the surface of the boards. Finally, the boards were coated using a vacuum coater with Akzo Nobel, water-based polyurethane with a tint added to give a different surface colour to the board than the natural colour found with ACQ (as Example 2 above). o Example 4: Use of a colourant, co-formulated with a preservative Trial using treatment solution including a micronized pigment (0.1% hostafine blue pigment CLARIANT) using vacuum / pressure techniques to show penetration effects. 5 Most pigments tend to have poor penetration in wood due to the filtering effect of the closely packed fibres and therefore a surfactant system with suitable wetting properties was used to carry the active ingredients into the timber. The surfactant system also assisted to maintain the actives in a stable suspended condition in the treatment solution in the presence of timber extractives and under plant conditions. 0 The surfactant system used in this trial comprised a proprietary combination of: 1. An amphoteric surfactant; and 2. A non-ionic surfactant. 25 Timber Kiln dried radiata pine samples were used, these were 20 mm thick decking boards and 11 mm thick sarking boards. The boards were sealed on their end grain using 2 coats of Resene Quick dry acrylic primer. 30 Trial conditions Action Pressure (Kpa) Duration (minutes) Initial vacuum -80 5 Treatment chamber flooding Solution drawn into chamber under vacuum 1 Soak 0 2 Treatment chamber draining Atmospheric pressure-gravity 1 Final Vacuum -80 5 0o4 29AUPR -16 Foam Control There were no signs of foam control problems even under vacuum and high agitation of the treatment solution. 5 Solution uptake An average uptake of 230 litres / cubic meter was achieved. Penetration of Dye Samples were cross cut and split using a chisel, full penetration of the pigment to a level of at least 10 mm was evident (full penetration of 20 mm boards). Penetration on dense annular 0 rings and heartwood was lower than in other parts of the timber but 10mm was evident. Conclusion Hostafine pigments are capable of deep penetration into timber using vacuum/pressure techniques, preferably together with a suitable wetting agent. 5 Radiata Timber products produced by methods of the invention that mimic the look of Cedar and which are suitable for applications such as cladding and decking can be seen in figures 1 to 8. Figures 1 to 4 show timber with a brushed finish to produce fine striations and figures 5-8 show timber with a band sawn finish. The surface finish and colour effectively mimic the look of 0 more expensive hardwood species. The complete penetration of the colour can be seen in figures 1 and 5. These products exemplify the advantageous properties produced by the invention that allow the radiata timber to mimic the aesthetic qualities of other timber species. Unless the context clearly requires otherwise, throughout the description and the claims, the 25 words "comprise", "comprising", and the like, are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense, that is to say, in the sense of "including, but not limited to". The entire disclosures of all applications, patents and publications cited above and below, if any, 30 are herein incorporated by reference. Reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that that prior art forms part of the common general knowledge in the field of endeavour in any country in the world. 35 0o4 29AUPR -17 Wherein the foregoing description reference has been made to integers or components having known equivalents thereof, those integers are herein incorporated as if individually set forth. It should be noted that various changes and modifications to the presently preferred 5 embodiments described herein will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the spirit and scope of the invention and without diminishing its attendant advantages. It is therefore intended that such changes and modifications be included within the scope of the invention.

Claims (32)

1. A method of processing Radiata timber to enhance the stability and aesthetic characteristics of the timber, the method comprising the steps of 5 a. applying a preservative; b. colouring the timber throughout its cross-section; c. lamination with a colourless or tinted glue to produce a vertical grain orientation on the face of the board; and d. surface finishing comprising the addition of one or more striations to the surface 0 of the timber.

2. A method according to claim 1 wherein colouring the timber is achieved by one or more of : a. thermal modification; b. furfyl modification; 5 c. resin impregnation; d. use of a colourant; or e. use of a preservative that has an inherent colour due to its chemistry.

3. A method according to claim 2 wherein when a colourant is used, it is applied concurrently with the preservative. 0

4. A method according to claim 2 wherein when thermal modification is used, it is carried out prior to applying the preservative and lamination.

5. A method according to any one of claims 1 to 4 wherein the striations are of less than 2.5mm in width.

6. A method according to claim 5 wherein the striations are of less than 1mm in width. 25

7. A method according to claim 2 wherein when a colourant is used, the colourant is a naturally occurring pigment or dye.

8. A method according to any one of the preceding claims wherein the preservative is selected from the group consisting of azole-based preservatives, tebuconazole, propiconazole, copper azole, ACQ and copper napthenate. 30

9. A method according to any one of the preceding claims wherein the one or more striations comprise: a. a band-sawn effect applied during band sawing of the laminated block into individual boards; or b. a micro-reed effect applied during profiling of the boards in a timber planar 35 operation; or c. a brushed effect applied using a brushing tool. 0o4 29AUPR - 19

10. A method according to any one of the preceding claims wherein a lamination glue line is disguised by the one or more striations.

11. A method according to any one of the preceding claims wherein the colouring, the glue, and the surface finishing are adjusted to result in a product that mimics the look of 5 Western Red Cedar, Kwila, Teak, Vitex, Ipe, Balau, Bankirai, or another timber.

12.A method according to any one of the preceding claims wherein the timber is produced from boards originally cut from a tree in a substantially flat grain orientation, wherein said boards are laminated together by gluing before being cut substantially perpendicular to the grain to produce individual boards with what appears to be a substantially vertical 0 grain orientation.

13.A method of processing Radiata timber to enhance the stability and aesthetic characteristics of the timber, the method comprising the steps of a. applying a preservative; 5 b. lamination with a colourless or tinted glue; c. surface finishing; and d. colouring the surface of the timber in final form through addition of a colourant in a water-based coating.

14. A method according to claim 13 wherein the colourant is applied concurrently with the 0 preservative.

15. A method according to claim 13 or 14 wherein the surface finishing comprises the addition of one or more striations.

16. A method according to claim 15 wherein the striations are of less than 2.5mm in width.

17. A method according to claim 16 wherein the striations are of less than 1 mm in width. 25

18. A method according to any one of claims 15 to 17 wherein the one or more striations comprise: a. a band-sawn effect applied during band sawing of the laminated block into individual boards; or b. a micro-reed effect applied during profiling of the boards in a timber planar 30 operation; or c. a brushed effect applied using a brushing tool.

19. A method according to any one of claims 15 to 18 wherein a lamination glue line is disguised by the one or more striations.

20. A method according to any one of claims 13 to 19 wherein the colourant is a naturally 35 occurring pigment or dye. 0o4 29AUPR - 20

21. A method according to any one of claims 13 to 20 wherein the preservative is selected from the group consisting of azole-based preservatives, tebuconazole, propiconazole, copper azole, ACQ and copper napthenate.

22. A method according to any one of claims 13 to 21 wherein the colouring, the glue, and 5 the surface finishing are adjusted to result in a product that mimics the look of Western Red Cedar, Kwila, Teak, Vitex, Ipe, Balau, Bankirai, or another timber.

23.A method according to any one of claims 13 to 22 wherein the timber is produced from boards originally cut from a tree in a substantially flat grain orientation, wherein said boards are laminated together by gluing before being cut substantially perpendicular to 0 the grain to produce individual boards with what appears to be a substantially vertical grain orientation.

24. A laminated timber product produced by a method according to any one of the preceding claims.

25.A laminated Radiata timber product wherein the surface of the timber has a surface 5 finish comprising one or more striations to disguise one or more glue lines from a lamination process; and wherein the timber is coloured to mimic the colour of a different wood; and wherein the timber is treated with a preservative.

26. A timber product as claimed in claim 25 wherein the different wood is Western Red 0 cedar, Kwila, Teak, Vitex, Ipe, Balau or Bankirai.

27. A timber product as claimed in claim 25 or 26 wherein the one or more striations comprise: a. a band-sawn effect applied during band sawing of the laminated block into individual boards; or 25 b. a micro-reed effect applied during profiling of the boards in a timber planar operation; or c. a brushed effect applied using a brushing tool.

28.A timber product as claimed in any one of claims 25 to 27 wherein the timber is produced from boards originally cut from a tree in a substantially flat grain orientation, 30 wherein said boards are laminated together by gluing before being cut substantially perpendicular to the grain to produce individual boards with what appears to be a substantially vertical grain orientation.

29. A method as claimed in claim 1, substantially as hereinbefore described with particular reference to any one or more of the examples and/or figures. 0o4 29AUPR - 21

30. A method as claimed in claim 13, substantially as hereinbefore described with particular reference to any one or more of the examples and/or figures.

31.A laminated timber product as claimed in claim 24, substantially as hereinbefore described with particular reference to any one or more of the examples and/or figures. 5

32.A laminated Radiata timber product as claimed in claim 25, substantially as hereinbefore described with particular reference to any one or more of the examples and/or figures.