AU2011200418B8 - Timber Laminates and Method for Constructing Same - Google Patents

Description

Timber Laminates, Composite Floorboards and Method for Constructing Same

Field of the Invention

This invention relates to a method for drying timber laminates for the purpose of producing a composite panel and has particular relevance to the formation of floorboards, composite floorboards and like panels from hardwood timber. It also relates to a method for producing a timber lamination, and a method for producing a laminate panel.

Background Art

Current technology for converting hardwoods, in particular eucalypt hardwoods, into engineered products is costly, as solid A grade timber is normally required. However, a substantial portion of the hardwood is lost to waste in lower grade timber, or used in significantly less valuable products, e.g. pallets.

When hardwood timber billets are initially sawn they are considered to be in a green state. These timber billets are generally cut to standard industry 20 dimensions. Green timber has a high water content in which free water in the cell lumen and bound water in the cell wall matrix are within the range of about 25 to 30 per cent by mass. The fibres in timber are bonded together in a chemical structural matrix that contains bound water.

Whilst free water can be dried off relatively easily, bound water is retained in the timber for longer periods.

When all the free water has been removed it has reached the fibre-saturation point (FSP). FSP is about 25 to 30 per cent moisture content (%mc).

Drying hardwoods is a more difficult process than drying softwoods due to the different fibre structures involved. Hardwood drying is slow due to the diffusion process. Diffusion is the movement of water molecules from an area in which they are highly concentrated to an area in which they are less concentrated.

-2Strong shrinkage forces are created during drying. To avoid wood cell (fibre) collapse and distortion of eucalyptus hardwoods the drying process must be slower than other species. Collapse will happen if water is removed too fast or in an uneven way from the timber. This happens because once free water is removed the remaining chemical structure cannot get rid of its bound water as quickly and will lose its shape rather than its bound water molecules.

Therefore, timber will always work to keep itself in equilibrium (balance) and as water is removed slowly from the outer surfaces more water will move from the higher moisture content areas to the lower moisture content areas.

It is against this background that the present invention has been developed

Summary of the Invention

It is an object of the present invention to overcome, or at least ameliorate, one or more of the deficiencies of the prior art mentioned above, or to provide the consumer with a useful or commercial choice.

Other objects and advantages of the present invention will become apparent from the following description, taken in connection with the accompanying drawings, wherein, by way of illustration and example, a preferred embodiment of the present invention is disclosed.

According to a first broad aspect of the present invention, there is provided a method for producing a composite wooden laminate panel, the method comprising the steps of: producing a one or more of first inner laminations, a pair of second inner laminations, a first outer lamination, and a second outer lamination; and laminating the laminations together such that the first inner laminations and the second inner laminations are located between the first outer lamination and the second outer lamination, and such that the one or more first inner laminations are located between and substantially co-planar with the second inner laminations, wherein the one or more first inner laminations have a grain direction transverse to a grain direction of the second inner laminations.

-32011200418 10 Sep 2015

In an embodiment the grain direction of the one or more first inner laminations are substantially perpendicular to the grain direction of the second inner laminations.

In an embodiment the one or more first inner laminations extend in length transverse to the direction of the lengths of the second inner laminations. Preferably the lengths of the one or more first inner laminations are substantially perpendicular to the lengths of the second inner laminations.

Section intentionally left blank

-42011200418 10 Sep 2015

In an embodiment the one or more first inner laminations extend in length transverse to the direction of the lengths of the second inner laminations. Preferably the lengths of the one or more first inner laminations are substantially perpendicular to the lengths of the second inner laminations.

Preferably, a wood grain direction of at least one of the one or more first inner laminations is substantially perpendicular to a wood grain direction of the first outer lamination, and a wood grain direction of the second outer lamination.

Preferably, the one or more first inner laminations are separated from each other by a gap.

Preferably, one of the second inner laminations cooperates with the first outer lamination and the second outer lamination to form a groove of the composite wooden laminate panel.

Preferably, one of the second inner laminations cooperates with the first outer lamination and the second outer lamination to form a tongue of the composite wooden laminate panel.

Preferably, at least one of the first outer lamination, second outer lamination, and the second inner laminations is of a higher grade than the one or more first inner laminations.

Section intentionally left blank

-52011200418 10 Sep 2015

According to a second broad aspect of the invention there is provided a method for producing a composite wooden laminate panel, the method comprising the steps of:

producing a one or more first inner laminations, a pair of second inner laminations, a first outer lamination, and a second outer lamination; and laminating the laminations together such that the one or more first inner laminations and the second inner laminations are located between the first outer lamination and the second outer lamination, and such that the one or more first inner laminations are also located between the second inner laminations, wherein the one or more first inner laminations extend in length transverse to the direction of the lengths of the second inner laminations.

According to a third broad aspect of the present invention, there is provided a composite wooden laminate panel produced using the method according to the fourth broad aspect of the present invention.

Section intentionally left blank

-62011200418 10 Sep 2015

According to a fourth broad aspect of the present invention, there is provided a composite wooden laminate panel comprising a first outer lamination, a second outer lamination, a one or more first inner laminations located between the first outer lamination and the second outer lamination, and a pair of second inner laminations located between the first outer lamination and the second outer lamination, wherein the one or more first inner laminations are also located between the second inner laminations, wherein the one or more first laminations have a grain direction transverse to a grain direction of the second laminations.

According to an fifth broad aspect of the present invention, there is provided a composite wooden laminate panel comprising a first outer lamination, a second outer lamination, a one or more first inner laminations located between the first outer lamination and the second outer lamination, and a pair of second inner laminations located between the first 15 outer lamination and the second outer lamination, wherein the one or more first inner laminations are also located between the second inner laminations, wherein the one or more first inner laminations extend in length transverse to the direction of the lengths of the second inner laminations.

Preferably the outer laminations are of a higher quality than the inner laminations. Preferably the outer laminations and the inner laminations are of a lower quality than laminations of an upper layer of the laminate panel.

Section intentionally left blank

-7According to a sixth broad aspect of the present invention, there is provided a composite timber laminate panel formed by one of the methods defined above.

Section intentionally left blank

-8Preferably, the method also comprises the step of applying a substantially waterproof seal to the panel.

Brief Description of the Drawings

In order that the invention may be more fully understood and put into practice, a preferred embodiment thereof will now be described with reference to the accompanying drawings, in which:

Figure 1 is a perspective view of a composite wooden laminate panel; and

Figure 2 is a cross-sectional plan view of the composite wooden laminate panel depicted in figure 1.

Best Mode(s) for Carrying out the Invention

A method for drying timber laminate for the formation of wooden panels and composite which can be used as floorboards will now be described. In the examples described, the floorboards produced by the method are formed from eucalypt hardwood, although it will be appreciated that the method is applicable to other woods or wood like materials, including bamboo.

Section intentionally left blank

-9Green timber billets having standard industry dimensions of 2100mm long x 165mm wide x

27mm thick and a high moisture content, for example, about 25 40% moisture by mass are cut to form one or more panels having a thickness which is substantially reduced, for example within the range of about 5mm to 15 mm, such as 7mm.

The panels are then subjected to a drying step conducted in, for example, a kiln.

The drying step is performed at relatively low temperatures comparative to dry bulb and wet bulb temperatures (measurement of these two parameters allows calculation of the relative humidity within the kiln). The dry bulb temperature is within the range of about 25 °C and 50 °C and wet bulb temperature within the range of about 25 °C and 50 °C, although the dry bulb temperature and wet bulb temperature are not required to be equivalent. The relative humidity within the kiln is maintained at, at least about 50%, for example within the range of 45% and 85%. This prevents the panels from drying too rapidly and minimises the, occurrence of fibre cell collapse, resulting in a maximum recovery of timber and less waste.

The residence time of the panels within the kiln is substantially reduced, being within the range of about 3 to 10 days, for example about 3 to 4 days.

The panels are then directed to a sanding step where they are sanded to a uniform thickness of 5mm +/- 0.1 mm, and are then visually graded for quality. The higher quality panels are utilised for the upper surface of a composite laminate floorboard, whilst the lower quality panels form the core and lower surfaces. The panels are thus bonded together using methods known in the art.

Finally the composite wooden panels are machined to refine the edges and surfaces, before a finishing coat is applied. The finishing coat is substantially waterproof and minimised moisture loss or absorption by the panels.

The method provides a significant advantage over the standard industry practice, by reducing the overall floorboard manufacturing time to about 2 to 3 weeks, compared with 8 plus weeks using current methods.

-10It will be understood by a person skilled in the art that the desired moisture content will be dependent on the target market and the climate in the region.

Furthermore, the normal wastage from the standard drying practice can be up to 30 per cent. The method permits better positional targeting of each grade of timber to one of the layers of the floorboard i.e. face, core and back. This results in a recovery of up to about 98% or higher. Thus, wastage is substantially reduced.

Referring to figures 1 and 2, a composite wooden laminate panel 10 includes a first outer lamination 11, a second outer lamination 12, a plurality of first inner laminations 13, and a pair of second inner laminations 14.

The laminations 11, 12, 13, 14 are laminated together such that a length of each of the first inner laminations 13 is substantially perpendicular to a length of the second inner laminations 14. The lengths of the first inner laminations 13 are also substantially perpendicular to a length of the first outer lamination 11, and a length of the second outer lamination 12. Typically a wood grain of the laminations are substantially parallel to the lengths of the laminations 11, 12, 13, or 14. Alternatively or additionally, the laminations 11, 12, 13, 14 are laminated together such that a wood grain direction of each of the first inner laminations 13 is substantially perpendicular to a wood grain direction of the second inner laminations 14, a wood grain direction of the first outer lamination 11, and a wood grain direction of the second outer lamination 12. The wood grain direction of each of the first inner laminations 13 is indicated by the arrows 15. The wood grain direction of the second inner laminations 14 is indicated by the arrows 16. The wood grain direction of the first outer lamination 11 and the second outer lamination 12 is indicated by the arrows 17.

The laminations 11, 12, 13, 14 are secured together with a suitable securing means. For example, the laminations 11, 12, 13, 14 may be secured together with a suitable adhesive such as wood glue.

The laminations 11, 12, 13, 14 are produced by cutting them from one or more larger pieces of wood (e.g. a timber log or timber/wood billet) having a high moisture content. In particular, the laminations 11, 12, 13, 14 are cut from a larger piece of wood which is green instead of dry.

-112011200418 13 Apr 2013

The laminations 11, 12, 13, 14 are then dried in a kiln to reduce their moisture content. Preferably, the pressure environment inside the kiln during the drying process is a negative pressure environment so that the laminations 11, 12, 13, 14 are dried in a vacuum or a partial vacuum. It has been found that negative pressure or vacuum drying uses less energy than non-vacuum drying. In addition, it has been found to cause less deterioration of the material that is being dried, and also enables a high quality final flattened lamination to be produced. The use of negative pressure in the drying process allows the moisture in the laminations 11, 12, 13, 14 to be more rapidly and efficiently removed compared to using traditional drying methods which rely on diffusion of water molecules naturally through the wood being dried.

As the laminations 11, 12, 13, 14 are dried, they are weighted and conditioned to de-stress and flatten them. This involves applying a specified amount of downward force to the laminations 11, 12, 13, 14 as they are dried in the kiln. The downward force along with the kilning conditions removes the inherent stresses that are within the laminations 11, 12, 13, 14 that, if not removed, could contribute to failure of the panel 10. If the weighting and conditioning process is not used, it would not be possible to de-stress and flatten the green laminations 11, 12, 13, 14 as they are drying. This allows the green laminations 11, 12, 13,

14 to be kept very flat.

During the conditioning process, the laminations 11, 12, 13, 14 can be impregnated with different types of treatments. Steam can be used with various treatments (e.g. anti-fungal etc.) so that the steam treatment molecules are absorbed into each of the laminations 11,

12, 13, 14 of the panel 10 instead of just on the surface of the panel 10. The steam combined with the heat of the drying process elasticises the laminations 11, 12, 13, 14. In other embodiments, the usage of steam in combination with heat to elasticise the laminations may be omitted.

Traditionally, in the manufacturing of premium flooring substrates or timber of a high grade, only the highest grade timber can be harvested from a log. However, with the three layer construction of the panel 10, it is possible to use more of the log than would traditionally be used. If material from the log is not graded as being of a high face grade, the material can be utilised in parts of the panel 10

-122011200418 13 Apr 2013 such as the inner laminations 13 where the appearance of the material is of no consequence but where structural ability or strength is important. This enables the percentage of the log that is used in the construction of the panel 10 to be very high, and at the same time enables the production of a panel 10 that is a premium standard product. Thus, lower grade timber logs can be used to produce high grade products.

In addition to the three layer construction of the panel 10, the process of cutting green billets or laminations also assists in achieving up to approximately 98% recovery of timber from the piece of wood from which the laminations are cut. In some instances, 100% of the piece of wood from which the laminations 11, 12, 13, 14 are cut can be utilised in the construction of the panel 10. This makes the process of constructing the panels 10 a highly efficient one at least from the standpoint of the percentage of raw timber material that is used.

If the laminations 11, 12, 13, 14 were cut from a dry piece of timber, it would be very difficult if not impossible to achieve such results, and would take substantially longer to dry the timber. This is because, traditionally, when large sections of timber are kiln dried, a lot 20 of waste is created.

The laminations 11, 12, 13, 14 in this example are hardwood laminations. In particular, the laminations 11, 12, 13, 14 in this example are Australian Eucalypt laminations.

The above-described process of cutting, drying, weighting and conditioning the laminations 11, 12, 13, 14, and forming the panel 10 from the laminations 11, 12, 13, 14 has been developed specifically for Australian Eucalypt timbers that have a lot of inherent tension from spiral grain, gum vain, tension wood, compression wood, sap pockets, and varying moisture contents across the timber. When large amounts of timber are put into a kiln, there always tends to be a lot of wast through the ends splitting, surface checking (small cracks), and distorting etc. A large section of wood will have a lot of strength in it and no matter how much weight is put on it, it can easily distort.

-13Although the above-described process has been developed specifically for Australian

Eucalypt timbers, it can nevertheless be used with other types of woods and wood-like plant materials, such as bamboo.

By cutting the wood into the laminations 11, 12, 13, 14 that are laminated together to form the panel 10, rather than forming the panel 10 from a single piece of wood as is traditionally done for floor boards etc., the inherent stresses in the laminations 11, 12, 13, 14 are overpowered, and the traditional kilning process issue of a large amount of waste is overcome.

Cutting the wood into the laminations 11, 12, 13, 14 also enables more exact control of the moisture content within the processed wood. The outside of wood always dries faster than its inside. However, by cutting thinner sections such as the laminations 11, 12, 13, 14, it is possible to better control the moisture content of the panel 10, which may be a floor panel or board, so that it is the same or substantially the same throughout the panel 10. The panel 10 has the same or substantially the same moisture content throughout and the same or substantially same de-stressed component (i.e. laminations 11, 12, 13, 14) throughout, so that essentially the whole structure/panel 10 is more stable than it would otherwise be.

All the waste/imperfect timber from the piece of timber from which the various laminations are cut is turned into the small section laminations (i.e. first inner laminations 13) that are laid across the face of the board/panel 10 (i.e. cross engineering). This allows all the odd sized, low grade, fall down material from the piece of timber/log to be used as part of the structure of the board/panel 10. By using the same material throughout, this gives the board/panel 10 better structural integrity. The first inner laminations 13 may be separated from each other by small expansion gaps 18 to assist in the event of the laminations 13 expanding due to high moisture.

The small section billets/second inner laminations 14 are positioned along either side of the floor board/panel 10 to lock the centre of the panel 10 away from variations in the environment. The second inner laminations 14 cooperate with the first outer lamination 11 and the second outer lamination 12 to form a tongue

-1419 (from lamination 14a) and a groove 20 (from lamination 14b) of the panel 10. The tongue 19 and groove 20 can function better than the tongue and groove of a traditional panel.

As mentioned above, the use of billets/laminations in the construction of the panel 10 allows almost 100% recovery of timber from the piece of timber from which the billets/laminations are cut. A bend in a solid and thick piece of wood that is a couple of metres long is detrimental to the manufacturer of a plank of wood, however when it is broken down into smaller sections such as the laminations 11, 12, 13, 14, such a bend has a negligible effect.

Engineered floorboards are traditionally made from materials (e.g. pine, birch, etc.) that are less expensive and softer than the materials from which the laminations 11, 12, 13, 14 are made. Each lamination, including the inner laminations 13, of the panel 10 is preferably made from the same material or type of wood, and all or most of the log from which the laminations are cut is used. Instead of turning lower grade material into chip wood, it is used to make the laminations 13 whose appearance is not important but whose strength is. Higher grade/premium timber is used for the laminations that will function as the face or faces of the panel 10. Using the same type of material for all of the laminations makes the board/panel 10 more stable and also ensure that the whole board/panel 10 has the same insect resistance throughout for the particular timber that the laminations of the panel 10 are made from.

In some embodiments of the invention, this can be contrasted with using different types of timbers for the different laminations. For example, if the top layer of the panel 10 were to be made from Jarrah, and the lower layers were to be made from Pine, the whole product/panel 10 would be more susceptible to being attacked by termites. However it will be appreciated that the present invention can use different types of laminations in the same floor panel.

The fibres of the laminations 11, 12, 13, 14 are de-stressed using steam and heat. This elasticises the fibres and enables the laminations to be flattened. A similar process is often used when bending timbers for furniture and boat manufacture.

-152011200418 13 Apr 2013

The above-described process for producing the panel 10 allows raw green log material can to be turned into a dry, premium floor board/panel within days and with minimal waste.

In contrast, if the panel 10 was produced using traditional methods that include drying the piece of timber from which the laminations are cut prior to cutting the laminations, the process could take up to six months from log splitting/cutting to manufacture.

Western Australian Eucalypt species are inherently imperfect in their appearance as a result of damage from fire, lightning, etc. in the growing phase. The raw material/laminations of the panel 10 are filled and finished to correct such imperfections 10 prior to the installation/use of the board/panel 10.

The above-described process of producing the panel 10 allows the laminations to be cut from a timber log whose quality does not need to be as high as would be required in the case of conventional timber flooring.

There is minimal deterioration in the wood of the panel 10 as a result of the wood being rapidly processed. The above-described process of producing the panel 10 enables the use of B grade timber without wasting, or minimising the wastage of the resource/timber.

Boards/panels such as the panel 10 that are produced using the above-described process can be larger and wider than solid conventional floor boards/panels whilst remaining flat and stable.

The process of producing the panel 10 means that there are six faces (i.e. the two main 25 faces of the first outer lamination 11, the two main faces of the second outer lamination 12, and the two main faces of the lamination that includes the first inner laminations 13 and the second inner laminations 14) to choose from for use as the surface or face of the floor board/panel, and provides the opportunity for the other/remaining five faces to be of a lower quality than the floor board/panel face while still enabling a premium product to be 30 produced.

The process of disposing the grains of the laminates in different directions is highly suited to producing composite floor panels from a variety of woods and wood-link plant materials, such as bamboo.

-162011200418 13 Apr 2013

It will be appreciated by those skilled in the art that variations and modifications to the invention described herein will be apparent without departing from the spirit and scope thereof. The variations and modifications as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of the invention as herein set forth.

Throughout the specification and claims, unless the context requires otherwise, the word comprise or variations such as comprises or comprising, will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other 10 integer or group of integers.

Throughout the specification and claims, unless the context requires otherwise, the term substantially or about will be understood to not be limited to the value for the range qualified by the terms.

It will be clearly understood that, if a prior art publication is referred to herein, that reference does not constitute an admission that the publication forms part of the common general knowledge in the art in Australia or in any other country.

Claims (15)

1. CLAIMS:

   1. A method for producing a composite wooden laminate panel, the method comprising the steps of:

   producing a one or more first inner laminations, a pair of second inner laminations, a first outer lamination, and a second outer lamination; and laminating the laminations together such that the first inner laminations and the second inner laminations are located between the first outer lamination and the second outer lamination, and such that the first inner laminations are located between and substantially co-planar with the second inner laminations, wherein the first inner laminations have a grain direction transverse to a grain direction of the second inner laminations.
2. 2. A method according to claim 1, wherein the grain direction of the first inner laminations are substantially perpendicular to the grain direction of the second inner laminations.
3. 3. A method according to claim 1 or 2, wherein the first inner laminations extend in length transverse to the direction of the lengths of the second inner laminations.
4. 4. A method according to claim 3, wherein the lengths of the first inner laminations are substantially perpendicular to the lengths of the second inner laminations.
5. 5. A method for producing a composite wooden laminate panel, the method comprising the steps of:

   producing a one or more first inner laminations, a pair of second inner laminations, a first outer lamination, and a second outer lamination; and laminating the laminations together such that the first inner laminations and the second inner laminations are located between the first outer lamination and the second outer lamination, and such that the first inner laminations are located between and substantially co-planar with the second inner laminations, wherein the first inner laminations extend in length transverse to the direction of the lengths of the second inner laminations.

   -182011200418 10 Sep 2015
6. 6. A method according to any of claims 1 to 15 wherein the produced laminations are graded, with lower quality laminations used in the inner laminates and higher quality laminations used in an upper layer of the laminated panel.

   5
7. 7. A composite wooden laminate panel produced using the method according to any of claims 1 to 6.
8. 8. A composite wooden laminate panel comprising a first outer lamination, a second outer lamination, a one or more first inner laminations located between the first outer

   10 lamination and the second outer lamination, and a pair of second inner laminations located between the first outer lamination and the second outer lamination, wherein the first inner laminations are located between and substantially co-planar with the second inner laminations, wherein the first inner laminations have a grain direction transverse to a grain direction of the second inner laminations.
9. 9. A composite wooden laminate panel comprising a first outer lamination, a second outer lamination, a plurality of first inner laminations located between the first outer lamination and the second outer lamination, and a pair of second inner laminations located between the first outer lamination and the second outer lamination, wherein the first inner

   20 laminations are also located between the second inner laminations, wherein the first inner laminations extend in length transverse to the direction of the lengths of the second inner laminations.
10. 10. A composite wooden laminate panel according to claim 8 or 9, wherein the outer

    25 laminations are of a higher quality than the inner laminations.
11. 11. A composite wooden laminate panel according to any of claims 8 to 9, wherein the outer laminations and the inner laminations are of a lower quality than laminations of an upper layer of the laminate panel.
12. 12. A floor comprising a covering of a plurality of composite wooden laminate panels of the type according to claim 7.

    2011200418 10 Sep 2015
13. 13. A method of providing a floor covering comprising producing a plurality of composite wooden laminate panels according to any of claims 1 to 7 and installing the composite wooden laminate panels on a floor.

    5
14. 14. A composite wooden panel substantially as herein before described with reference to the accompanying drawings.
15. 15. A method of forming a composite wooden panel substantially as herein before described.