AU2011288929A1 - Producing a veneer - Google Patents

Abstract

The present invention relates to a product such as a veneer made from plant materials such as, but by no means limited to, banana plants. The invention also relates to a method and apparatus for producing the product which includes slicing the plant material into elongated strips and pressing the strips to expel water and reduce the water content of the strips so that the strips are suitable for making into a veneer.

Description

WO 2012/019247 PCT/AU2011/001041 PRODUCING A VENEER Field Of Invention The present invention relates to a product including plant material such as, but by no means limited to, banana plants. The present invention also relates to a method and 5 apparatus for the production of the product. Background Of The Invention It is to be understood that, any prior art publication or information mentioned or referenced in this specification, does not constitute an admission that the publication or information forms a part of the common general knowledge in the art. in Australia or any 10 other country. There are 50 or more species in the genus Musa including all the plants commonly referred to as banana or plantain. The main source of this material is expected to be, but not limited to edible-fruited banana plants and plantains. The term "banana" is the common name for herbaceous plants of the Genus: Musa, 15 Order: Zingiberales, Family: Musaceae and for the fruit they produce. The term "banana" in commerce and daily culture also refers to the soft, sweet "dessert" fruit of the banana plant, with the 'Cavendish' variety being the main commercial dessert cultivar. The bananas from a group of cultivars with a firmer, starchier fruit are called plantains or Pisang Awak in Asia and are normally used for cooking. 20 The banana is the most important fruit crop of the wet tropics. The banana is not a tree, but a giant herbaceous plant, springing from a thick underground stem or rhizome usually called a corm by growers. The "trunk" is a pseudostem formed of tightly rolled leaves unfurled only at the crown. The banana plant is considered a perennial plant although the pseudostem dies 25 after producing fruit. This is due to suckers successively replacing the senescent aerial parts without the need for replanting. These suckers normally emerge consecutively from buds located at the axial of leaves. Under normal circumstances and especially under commercial cultivation, these suckers are regularly pruned or cut, leaving the most healthy and vibrant sucker. This is to ensure that the best sucker grows into a healthy fruit producing plant.

WO 2012/019247 PCT/AU2011/001041 -2 Bananas are harvested all year-round, with normal commercial bunch weights of 15-30 kg, although bunches of more than 45 kg are not unusual when properly cultivated. A medium-sized dessert banana finger weighs around 160g. Bananas are native to tropical Southeast Asia, and are likely to have been first 5 domesticated in Papua New Guinea. Today, they are cultivated throughout the tropics. They are grown in at least 107 countries, primarily for their fruit and to a lesser extent to make fibre. The moisture content of fresh banana pseudostems may be in the range of 90 to 96% by weight. Banana pseudostem has lower lignin content than wood and straw. While 10 the ash and extractive contents in banana pseudostem are higher than that of wood fibres, they were still lower than straw. Banana pseudostem therefore has potential in application of pulping and papermaking because of its acceptable content of cellulose and holocellulose and low lignin content. Whilst banana and plantain plantations are an important industry in many countries, 15 the commercial cultivation of banana has been associated with a number of negative environmental impacts. The commercial production of banana is a permanent cultivation that has established itself as intensive and mono-cultural. It is a cultivation, predominately undertaken in tropical environments that requires the following:- large amounts of land; control over the amount of ground-water; systems of canals and drainage ditches; high 20 levels of fertilisers and pesticide application; careful attention to plant de-leafing, de suckering and maintenance; a substantial labour force. There is therefore a significant impact on environmental health including:- a change in soil use; deforestation in order to extend areas of cultivation; the loss of tropical flora and fauna bio-diversity; processes of sedimentation and erosion which leave the soil exposed; 25 contamination of the soil, atmosphere, ground and subterranean waters deriving from the high application rates of artificial fertilisers; the loss of ground-water resources, owing to the diversion or transformation of ravines or rivers into drainage canals for the plantations; regular and irregular discharges of contaminated waste water; acute and chronic effects on the health of plantation workers; (negative) agro-ecological effects. 30 Banana plantations generate a large amount of organic wastes. This is all produced by the ongoing activity of banana farming and commercial packaging. After harvesting banana bunches from the trees, a large amount of waste biomass remains, because each pseudostem cannot be used for the next harvest. These bare pseudostems are normally WO 2012/019247 PCT/AU2011/001041 -3 felled and usually abandoned to become organic waste and cause environmental pollution. In some countries it is so serious that they are carted away to be disposed in landfill sites. Normally, the parts that constitute the banana pseudostem themselves are of a bulky, fibrous vegetal material which is difficult to break down and retards the natural 5 processes of decomposition such as photo-degradation, oxidisation, bacterial degradation etc. Bacterial degradation is affected additionally by being placed in the middle of an area where many chemicals (particularly fertilizers and pesticides) are used. The poor disposal and lack of special treatment for these biodegradeable wastes produces a proliferation of harmful organisms. At the same time, the leachate reaches the 10 ground and underground water supplies, affecting their quality. There are a number of references to the use of tropical waste materials derived from banana or plantain stalks or pseudostems and other plants for the production of useful products. For example, US patent 5,958,182 discloses a process for recovering fiber from the 15 cultivation of banana, plantain, pineapple, coconut and other tropical fruit bearing crops. These fibres could then be used in a number of applications including the absorption of liquids, paper making, textiles, insulation and general fiber fillers. The processes described refer to the use of the plant stalks or crowns and its conversion into fibres using various chemicals such as alum, sodium hydroxide, potassium hydroxide or hydrogen peroxide. 20 US patent 4,547,263 discloses an apparatus and a process for the use of the plantain stem using a mixture of acids, alkalis and bleaches is described for the production of products such as paper pulp. International patent publication WO 2006/029469 discloses a method and apparatus for the production of paper products using the fibres from banana plants without 25 going through a pulping process. In publication discloses that continuous sheets of fibres are removed using a fibre separating device which relies on rotary peeling of the entire pseudostem followed by laminating these sheets and curing it to form raw paper. It is also clearly evident that the rotary apparatus requires the apparatus to adjust for a decreasing diameter of the rotating pseudostem, thereby requiring highly sophisticated 30 equipment and control systems to enable it to form the sheets required for paper production, especially when the pseudostem contains high moisture and is of diverse chemical composition.

WO 2012/019247 PCT/AU2011/001041 -4 It is an object of the present invention to provide an alternative product, and an apparatus and method for the production of the product. Summary Of The Invention The present invention relates to a method of producing a product that can be used 5 as a veneer, the method includes the steps of: slicing a stem of a plant to form strips, the stem is sliced in a longitudinal direction so fibre is oriented longitudinally along the strips, and wherein the strips have a water content of at least 50% by weight; and pressing the strips to expel water from the strips and reduce the water 10 content of the strips to form the product. Throughout this specification, the term "stem" embraces any elongated part of any type of a plant including pseudostems, shoots, trunks, and alike. The plant may be any plant of the Musa genus, and suitably of the Musaceae family including banana and plantain. The term "stem" includes pseudostems of the banana plants and stem of plantain, or parts 15 thereof. Throughout this specification, the term "veneer" embraces any covering, such as a fibrous wood covering that can be applied to a substrate. Typically, but not necessarily, the veneer will have either one or a combination of a more attractive appearance, or desired physical properties such as robustness or hardness compared to the substrate. 20 In one example, the strips may extend only part way along the length of the stem, or in another example, the strips may extend the entire length of the stem. The strips may be longitudinal cross-sections extending along the length of the stem. The cross-section may be partial cross-sections of the width or height of the stem, and, suitably cross-sections that extend completely across the width or height. 25 The pressing step reduces the water content of the strips to less than or equal to 50% or 30% by weight, and suitably to a content of less than or equal to 25% by weight, and even more suitably, to a content of less than or equal to 20%, 18, 15, 13, 10, 8, 5 or 3 % by weight. The water content may be greater than or equal to 0.05%, 0.5% or 1.0% by weight. The strips prior to the pressing step may have a water content of equal to or greater 30 than 60, 65, 70, 75, 80, 90% by weight, and suitably have a water content ranging from 90 to 98%, and typically have a water content ranging from 94 to 96% by weight. The water WO 2012/019247 PCT/AU2011/001041 -5 content may vary to some extent depending on when the stem was cut from the plant. For example, in the case of banana psuedostems, the water content is typically in the range of 90 to 96% when cut from the plant, or within a day thereof. However, it is unlikely for the water content to drop below 50% by weight on exposure to ambient conditions and still be 5 suitable for making a product such as a veneer. References to water content throughout this specification also brace moisture content. Slicing the strips from the stem may, in one example, include slicing multiple strips simultaneously or over periods that partially overlap so as to be partially concurrent. In another example, slicing the strips from the stem may include slicing the strips successively 10 from the stem. In yet another example, the strips may be cut from two or more stems concurrently. Slicing the strips from the stem may be carried out using any slicing mechanism including piercing water jets, lasers, and cutting blades including knives and wires such as tensioned wires or heated wires. The blades may or may not have a sharpened edge, or a 15 set of teeth. Suitably, slicing mechanism includes a set of blades, such as wires, that are spaced apart for forming strips above, below or between the wires. Ideally, the slicing step includes moving the set of the blades and the stem relative to each other so that the blades cut along the stem to form strips. While the wires may be moved in a longitudinal direction of the 20 stem, suitably, the stem is driven into the blades and the blades reciprocate in a direction transverse to the direction of movement of the stem. Suitably, the blades include tensioned wires, and the set of blades may include a set of reciprocating tension wires that are spaced apart. The strips may have a thickness ranging from 1.5mm to 6.0 mm, and suitably range 25 from 2.0 to 5.0 mm, prior to the pressing step. The strips may have a length ranging from 0.5 to 4.0m, and suitably range from 1.0 to 3.0m. The stem has a more dense inner core and a less dense outer portion, and the method may include a preliminary step of removing an outer portion from the inner core such 30 that the step of slicing the strips includes slicing cross-sections extending longitudinally along the inner core of the stem. For example, the inner core of a pseudostem of a banana plant has a greater density than the outer portion of the stem.

WO 2012/019247 PCT/AU2011/001041 -6 The pseudostem of a banana plant may have an outer portion comprising leaves wrapped about the inner core. The inner core may include an outer layer or skin that extends about the inner core and separates the inner core from the outer portion of the stem. The outer skin of the inner core may have a hard and shiny appearance relative to 5 material beneath the outer layer. In our experience, this outer layer of the inner core does not bond to other material of the inner core in the same way as the other material beneath the outer layer. For this reason, the outer skin is suitably separated from the inner core. Separation of the outer layer may be carried out prior to, or after, slicing the stem. In the case where the outer layer is removed after the stem has been sliced, the outer layer may 10 be removed by cutting the outer layer from the edges of the strips sliced from the stem. The outer portion of the stem may be removed by cutting away the outer portion from the inner core in a longitudinal direction of the stem or circumferentially about the stem. For example, the outer portion may be cut away in layers, flakes or peels removed from the stem. This step may be carried out manually in the field of a farm using knives or by using 15 machinery. In another example, removing the outer portion from the stem includes the stem passing through a cutting assembly having an opening through which the stem moves in a longitudinal direction, the outer portion of the stem is removed from an inner core of the stem as the stem enters and passes through the opening. In other words, the inner core passes through the opening as the outer portion is removed in an annulus from the inner core. The 20 opening may also be sized to remove the outer layer of the inner core. The method may also include separating fibres from the outer portion to provide fibres suitable for use in the paper/paperboard and construction board industry. While the cutting assembly may include a range of cutting mechanisms including water jets, lasers, milling and so forth. Suitably, the cutting assembly includes a blade 25 defining the opening and the outer portion is cut from the inner core so as to extrude the inner core through the opening. The opening may have any geometric shape including triangular, quadrangular, pentagon, hexangular, circular, oval, non-circular and so forth. It therefore follows that a cross-section transverse to the longitudinal direction of the inner core of the stem may have 30 a shape that conforms with the geometric shape of the opening. The method may include driving the stem through the opening of the cutting assembly. For example, while holding the cutting assembly and leading blade thereof stationary relative thereto.

WO 2012/019247 PCT/AU2011/001041 -7 The step of pressing the strips may include the strips being pressed without contacting other strips. The method may also include arranging the strips so that the strips at least partially overlap to form a sheet, and the pressing step includes pressing two or more than two strips while the strips are arranged in overlapping relationship. The 5 overlapping sections of the strips may laminate together during the pressing step by means of physical or chemical bonding either with or without the use of a bonding agent. The present inventors have realized that the inner core of the banana stem includes a number of the naturally occurring resins, latex and hardening components, and as such, it is typically unnecessary for the additional bonding agents to be added to the overlapping sections of the 10 strips to laminate the strips together. Arranging the strips may include locating the strips so that longitudinal side portions of adjacent strips overlap. The sheet formed from arranging the strips in this manner may be single ply sheet. Arranging the strips may also include locating the strips in two or more layers of which a first array of adjacently arranged strips form a first layer and second array 15 of adjacently arranged strips form a second layer and the layers are overlaid, so as to form a multilayered sheet. For example, the sheet may have only two layers of adjacently arranged strips in which case the sheet will be a two ply sheet. In another example, the sheet may have only three layers of adjacently arranged strips in which case the sheet will be a three ply sheet. The strips may be arranged to form sheets of any number of layers. 20 In any event, longitudinal side portions of adjacent strips of any of the layers may also overlap. For example, in the case of a three ply the opposite outer layers may include strips having overlapping side portions. The strips of the middle layer may or may not overlap. The strips may also be located so that the orientation in a longitudinal direction of 25 the strips of at least two layers (of a multilayered sheet) is different. The longitudinal orientation of the strips of different layers may be transverse to each other or they may be aligned in the same direction. In one example, the longitudinal direction of the strips of one layer may be arranged in a lengthwise direction of the sheet and the strips of a second layer may be arranged at an angle to the lengthwise direction, for example, in a widthwise 30 direction of the sheet. In another example, the longitudinal direction of the strips of one of the layers may be located in different orientations between adjacent strips or adjacent groups of strips, for example, in a herringbone pattern or in a lattice pattern. The step of arranging the strips in overlapping relationship to form sheets may include stacking the sheets with a divider located between the sheets. The divider may have WO 2012/019247 PCT/AU2011/001041 -8 any form including water absorbing properties, such as cotton fabric, and non-water absorbing properties, such as a polymeric film. The pressing step may be carried out by any pressing mechanism including continuous, semi-continuous or batch processes. By way of example, the pressing step may 5 include one or more rollers pressing the strips, such as with the strips being arranged on a table and a roller passing over the strips. In another example, the strips may pass between pairs of compression rollers, or in another example, the process may be carried out by a plate press in which the strips are located between two plates and a pressing loaded is applied to the plates. In any event, the pressing step may service the purpose laminated 10 overlapping strips and expelling water and moisture from the strips. The pressing step suitably includes apply a pressure to compress the strips by applying a pressure up to or less than 700 tons per square meter, and suitably in the range from 50 to 600 tons per square meter, and more suitably from 100 to 500, and even more suitably from 100 to 450 tons per square meter. 15 The pressing step may include applying a pressure to the strips in a plurality of stages in which pressure applied to the strips increases from one stage to the next. Each stage may be conducted for any period but is suitably at least 5 minutes, and even more suitably at least 10 minutes. The pressure applied in each stage may increase from one stage to the next, and suitably changes incrementally by pressure changes in the range of 20 20 to 150 tons per square meter and even more suitably, increases incrementally with pressure changes in the range from 20 to 50 tons per square meter from one stage to the next. By way of example, the pressing step may include pressing batches of 30 to 300 sheets stage-wise up to or less than a pressure of 700 tons per square meter, and suitably 25 approximately in the range of 400 to 700 tons per square meter, and each stage is conducted for a period of in the range of 5 to 15 minutes. Once the pressure has reached 120 tons per square meter, a stack of at least 180 sheets and suitably at least 250 sheets are formed, and the pressing step may include applying, to the stacks of sheets, a pressure that increases across a series of stages. For 30 example, the pressure applied to the stack may increase one stage to the next and range from 170 to 450 tons per square meter. Each stage of the pressing step may be applied to the stack for at least 10 minutes.

WO 2012/019247 PCT/AU2011/001041 -9 After the pressure applied to the sheets has been increased incrementally, the sheets may then subject to a pressure in the range from 500 to 700 tons per square meter for at least 4 hours. The pressing step may include a drying stage in which the sheets are subjected to 5 a pressure up to or less than 100 tons per square metre, and suitably ranging from 50 to 100 tons per square meter for a total of 5 to 24 hours, and typically 5 to 8. The dividers, suitably water absorbing dividers, are located between the sheets during the drying step, and the dividers may be changed from 4 to 8 times during the drying step. The drying step may be carried out after the stage-wise changes in pressure and 10 after a pressure ranging from 500 to 700 tons has been maintained for a period of at least 4 hours. The pressing step may include a finishing stage in which the dividers between the sheets have a porous non-water absorbing surface. For example, the sheets have a polymeric surface in contact with the sheets. 15 The method may also include a further drying or de-watering the product after the pressing step by air drying, and or kiln drying. The method may also include treating the core of the pseudostem or the strips to alter colouring of the strips, for example, reducing the brightness of the strips. The treatment may include any one or a combination of a natural ageing, the application of a chemical 20 reagent or thermal treatment. Thermal treatment may include exposing the strips to sunlight, or exposing the strips to ultraviolet radiation, for example, from an ultraviolet lamp. Chemical reagents include oxidizing agents, acids, alkalis and antioxidants such as sodium ascorbate and potassium metabisulphite. The step of treating the strips to alter colouring of the strips may be carried out prior to, or after, the step of pressing the strips. 25 The method may also include bonding the strips, or sheets of the strips, to a substrate such as medium density fibre board (MDF), particle board or other substrate. The present invention also relates to an apparatus that produces a product including plant material, wherein the apparatus includes: a slicing stage that slices a stem of a plant into multiple strips, the slicing 30 stage slices the stem longitudinally so that fibre of the stem is oriented longitudinally along the strips, and wherein the strips have a water content of at least 50% by weight; and WO 2012/019247 PCT/AU2011/001041 - 10 a pressing stage that presses the strips to expel water from the strips and reduces the water content of the strips to form the product. The slicing stage may have any cutting mechanism including piercing jets, for example jets of water or air, lasers and blades including high tensioned wires and alike. 5 Suitably, a plurality of the blades, spaced relative to each other, reciprocate laterally to the direction of movement of the stem which travels in a longitudinal direction through the cutting assembly. The blades suitably include tension wires that may be made of any type of the material include metallic material such as stainless steel wires, non-metallic wires such as nylon or any other polymeric material. The wire may also have a coating applied thereto 10 such as a diamond coating. In the situation in which the slicing stage includes a plurality of wires, the strips cut from the stem may pass between each of the wires. The slicing stage may have a driving assembly for driving the stem into the wire(s). The driving assembly may include a upstream support located upstream of the wire(s) that 15 supports the stem(s) so as to be oriented in a longitudinal direction toward the wire(s), a ram for engageing an end of the stem which drives the stem(s) toward the wire(s), and an actuator that is operable to move the ram forward and back along the guiding structure to push the stem(s) toward the blades. The slicing stage may also include a downstream support that is located 20 downstream of the wire(s) that receives the strips cut from the stem. The pressing stage may include a continuous pressing station or a batch pressing station. An example of a continuous pressing station is a conveyor for carrying the strips and a roller for pressing the strips onto the conveyor. An example of a batch process is a pressing station having opposed plates and an actuator operable for moving at least one of 25 the plates toward the other plate so that strips between the plates are pressed there between. The plant may also include a preliminary stage that removes an outer portion of the stem to provide an elongate inner core, and the slicing stage removes strips from an inner core of the stem. The preliminary stage may include a cutter assembly having an opening 30 through which the stem moves in a longitudinal direction, an outer portion of the stem is removed from an inner core of the stem as the stem enters and passes through the opening.

WO 2012/019247 PCT/AU2011/001041 - 11 While the cutter assembly may include a range of cutting mechanisms including water jets and lasers. The opening may be defined by grinding discs or grinding rollers that grind off the outer portion. Suitably, the cutter includes one or more blades that define the opening and the outer portion is cut from the inner core and the inner core of the stem 5 passes through the opening. The, or each, blade may be shaped including blades having triangular, quadrangular, pentagon, hexangular, circular, oval, non-circular and so forth. Suitably, the cutter assembly includes a circular blade supported by arms extending outwardly from the blade. The circular blade may have two or more interconnected or non-interconnected blade 10 sections. The plant may also include a drying stage that kiln dries the strips after the pressing stage. The plant may also include a treatment stage that reduces the brightness of the strips that includes either one or a combination of: i) a bath of chemical agents that are 15 applied to the strips, for example, by conveying the strips through the bath; or ii) a radiation exposure platform on which the strips are exposed to sunlight or ultraviolet light from a lamp or by natural ageing by time. The plant may also include any one or a combination of the features of the method of the present invention. 20 The present invention also relates to a product that is made according to any one or a combination of the features of the method of the present invention. The present invention also relates to product that can be used as a veneer, the product including at least one strip sliced in a longitudinal direction of a stem of a plant so that fibre is oriented longitudinally along the strips, and wherein the strips initially having a 25 water content of at least 50% by weight, and have been pressed so as to have a reduced water content. The product of the present invention may have any one or a combination of the features of the product made according to the method described herein. For example, the product may have water content in a range up to 20% by weight, and suitably in the range 30 from 8 to 18% by weight after being pressed. The product may also have thickness in the range of 0.08mm to 0.50 mm in thickness.

WO 2012/019247 PCT/AU2011/001041 - 12 Brief Description Of The Drawings An embodiment of the present invention will now be described with reference to the accompanying drawings, of which: Figure 1 is a schematic illustration of a banana plant of the genus Musa and family 5 Musaceae; Figure 2 is a schematic illustration of method steps of a preferred embodiment of the present invention for producing a product containing material from banana plants such as the plant shown in Figure 1; Figure 3 is a schematic illustration of an apparatus according to a preferred 10 embodiment for producing a product containing material from banana plants such as the plant shown in Figure 1; Figure 4 is a photograph of a cross-section of a pseudostem of a banana plant having, intacted, an outer portion and an inner core; and Figure 5 is a photograph of a cross-section of part of the inner core of a banana 15 pseudostem, the section of the inner core between the broken line in Figure 5 indicates a layer that forms a sheath or skin about the inner core. Detailed Description Of The Invention A preferred embodiment of the present invention will now be described with reference to the accompanying drawings and in particular with reference to a stem of the 20 banana plant in the form of the pseudostem. It will be appreciated that the stem, however, may be a stem of any plant including plants of the genus Musa. Figure 1 is an illustration of a banana plant 10. The plant includes an underground stem, typically referred to as a corm 11. Roots 12 extend from the corm 11 in the soil. The "trunk" is a pseudostem 13 having tightly rolled leaves unfurling at the crown. Once the plant 25 is fully grown the flower stalk is sent from the rhizome right through the pseudostem of the plant tip, growing vertically as it emerges then hanging down as the flowers develop. Male flowers 14 develop at the tip, forming an overhanging structure called the bell; female flowers 15 are located spirally around the flower stem and form the bananas 16. Each stem only produces one bunch; the plant then reproducing itself from the underground rhizome via 30 a sucker 17. The whole cycle from planting to harvesting of the single huge bunch takes WO 2012/019247 PCT/AU2011/001041 - 13 from 9 months near the equator to up to 18 to 24 months at the extreme latitudes for viable production of around 30 degrees North or South of the equator. The banana plant is considered a perennial plant although the pseudostem dies after producing fruit. Suckers successively replace the senescent aerial parts without the 5 need for replanting. These suckers normally emerge consecutively from buds located at the axial of leaves and mature in the next pseudostem from which fruit are produced after each pseudostem has been harvested. Figure 2 illustrates a method for producing a product containing material of a banana plant, such as a "Musa veneer" which refers to a product containing. 10 In step 1, banana pseudostems 13 of a height between 0.5 metres to 15 metres, but suitably between 1.5 to 2.5 metres are selected for use. In general the size and shape of banana pseudostems 13 suitable for use with the method of the invention is not important. An outer fibre portion 18 of the banana pseudostem will normally be of varying diameter along their length and will have a relatively rough and irregular exterior, consisting of formed 15 leaf sheaths. This needs to be removed before processing. In step 2, the banana pseudostems are cut or felled manually and or by mechanical means. This involves cutting at or near the base of the pseudostems 13 and the top of the pseudostems 13 below where the leaf fronds and the stalk containing the banana fruits 16 have emerged. 20 The pseudostems 13 may undergo a preliminary processing step on the mobile unit, tractor or truck 19, where the outer fibre portion 18 is separated from an central inner core 20 of the pseudostem and either both intermediate products or at least the inner core are then transported to a factory or location where it is then further processed. In this embodiment of the invention, any liquid generated from the pseudostem 18 can be returned 25 to the rest of the growing banana plants 10 providing an excellent source of natural nutrients to the plants. According to the preferred method, step 3 includes collecting the pseudostems 18 and transporting the pseudostems intact to a factory so that the preliminary processing step can be carried out in a factory. The preliminary processing step is ideally carried out within 1 30 to 5 days of harvest, or longer, if kept in conditions that do not promote its degradation particularly kept away from direct sunlight. If the strips are needed to be of a darker color the pseudostems may be left for maybe 5 to 10 days after the banana harvest in the paddock, either after being cut down or still attached to the root.

WO 2012/019247 PCT/AU2011/001041 - 14 The preliminary step, i.e., step 4 of the preferred embodiment, involves removing the outer portion 18 of the pseudostem 13 which comprises leaves of the plant wrapped about the inner core 20 (see Figure 4). The preliminary step may include removing the outer portion 18 of the pseudostem from the inner core 20. 5 As can be seen in Figure 5, the inner core 20 includes an outer layer 20a (or skin or sheath) about the inner core 20 that separates the outer layer 18 to the inner core 20. The outer skin layer 20a identified as the section of the inner core between the dashed line in Figure 5 and the extremity of the inner core 20 can, in our experience, be detrimental to the final product and is best removed from the stem at some stage during the method. 10 Specifically, the outer skin layer 20a does not adhere as naturally to the remainder of the inner core 20. The preliminary step 4 can be carried out by a cutting assembly 30 having a fixed blade 31 or rotating cutters that define an opening 32 through which the inner core 20 passes. In the case of the preferred embodiment shown in Figure 3, the cutting assembly 15 30 includes a ring shaped blade 31 through which the inner core 20 passes in a longitudinal direction so as to progressively separate the outer portion 18 from the inner core 20. The cutting assembly 30 may also have a supporting structure 33 and an actuator 34 that is operable to advance the pseudostem 13 along the supporting structure in the cutting assembly 30. The preliminary step 4 may be operated to remove the outer skin layer 20a 20 from the inner core 20 while the inner core 20 is intact. However, in our experience, the outer skin layer 20a can be conveniently removed at later stages. In any event, the preliminary step 4a produces an inner core 20 that is further processed to produce a veneer product. In the preferred embodiment a by-product 18b may be formed from the outer 25 portion separated from the pseudostem during the preliminary step. The by-product 18b may be formed by chopping the outer portion 18 into a range of lengths of varying widths by a shredder. The method may then include dewatering the chopped lengths via screw presses, belt presses and the like; drying the dewatered fibres to a moisture content of 10 to 30%; extruding and/or pelletising and/or baling and/or packaging the dried material suitable 30 for shipping to product the by-product 18b. The by-product 18b can be used as a feedstock or a source of fibre in a range of other processes but not limited to the production of feed for animals or humans, production of paper and paperboards, construction boards such as medium density fibreboards.

WO 2012/019247 PCT/AU2011/001041 - 15 In step 5 of the preferred embodiment, multiple strips are separated along the length of the inner core 20 of the psuedostem 13 using a slicing stage 40 shown in Figure 3. It will be apparent to those skilled in the art that slicing the psuedostem into strips 21 does not act to remove strips by cutting through fibres, but rather separates or removes strips 41 5 by virtue of mostly cutting between bundles of fibres along the entire length of the stem 20 that is being presented to the cutting stage 40. This method of separation retains the integrity of the fibre bundles in the separated strip and may extend along virtually the entire length of the banana pseudostem 20. During this step there may be some incidental damage to some fibres and some fibre bundles, and some of that damage may be due to the cutting 10 device those fibres and fibre bundles; however this does not detract from the principle aim of there being separation rather than cutting. As can be seen in Figure 3, the slicing stage 40 includes a plurality of spaced wires 42 that reciprocate laterally to the direction of movement of the stem 20 which travels in a longitudinal direction through the cutting assembly 40. The wires 42 may be of any material 15 including metallic, non-metallic and may even have teeth or other coatings such as diamond coatings applied thereto. The slicing stage has a driving assembly 43 for advancing the stem 20 into the wires 42, and an actuator 44 that is operable to move the ram 45 forward and backward along the guiding structure 46 to push the stem toward the wires 42. 20 The guiding structure supports the inner core 20 in a manner that provides the necessary structural support along its length. The inner core is driven lengthwise into the wires 42 which are positioned such as to allow the inner core to be separated into any number of longitudinal strips 41 (in one pass) the number of strips 41 produced being dictated by the diameter of the central inner material being used and the specified thickness 25 of the strips 41. The thickness of the strips 41 may be varied at this stage to deliver a suitable veneer product. In yet another form, the fibre-slicing device may be mechanical such as a laser cutter or high-pressure water cutting system, or adapted as appropriate to provide separation of strips in the manner described above. 30 In our experience, the outer skin layer 20a of the inner core 20 may be cut from the strips 41 by running a knife down the edges of the strips as part of step 5. Step 6 of the preferred embodiment may involve enhancing the value of the end product that controlling the appearance and colour of the strips. Step 6 may include the WO 2012/019247 PCT/AU2011/001041 - 16 strips being treated with a range of treatments, which include but are by no means limited to, immersion of the strips in a bath in water, naturally aged by time, alcohols, treated with ultra violet sunlight or lamps 51, heat or cold, oxidising agents, antioxidants such as sodium ascorbate and potassium metabisulphite, acids and alkalis to modify the pH of the strips for 5 various periods from as short as 1 minute to many hours. It will be apparent to a person skilled in the art that this will influence the appearance and colour of the strip and, thus, the veneer product. Step 6 may or may not be required depending on the customer requirements. Step 7 of the preferred embodiment includes arranging the strips on dividers 42 that 10 are either water absorbing or non-absorbing. The strips 41 are overlaid or overlapped in any direction to produce an assembled sheet 43 of material of a length dictated by the banana pseudostem stock but with unlimited width or length and pressing the sheets to expel water from the sheets in a continuous roller type press or static (batching) type press. The strips may also be arranged on the dividers 42 so not be overlaid or overlapping but separated by 15 spaces between the strips 41. In this step the inherent physical and chemical properties of the strips 41 of the inner core 20 of the banana pseudostem re-bonds itself without having to use any added binding chemicals such as adhesives, and it may be possible to produce sheets comprising a series of overlapping strips that have laminated and become integrated without the need for vast quantities of heat energy regardless of its source. Layons may also 20 be made by laminating two or more of these strips together such that the direction of the material is not relevant. The strips may also be arranged by locating the strips in one, two or more layers of which a first array of adjacently arranged strips form a first layer and a second array of adjacently arranged strips form a second layer and the layers are overlaid to form a multi 25 layered sheet. Table 1 below set out specific physical data including length, width and thickness of two and there layered sheets.

WO 2012/019247 PCT/AU2011/001041 - 17 Table 1 multi-layered Length Width Weight Thickness Density sheet cm cm g mm Density kg/m3 (veneer) g/cm2 3 ply 1 2 3 1 194 55 205 0.21 0.22 0.22 0.019213 915 2 193 54 210 0.2 0.21 0.19 0.02015 1,007 2 ply 1 200 55 139 0.12 0.11 0.11 0.012636 1,053 2 203 57 150 0.14 0.13 0.12 0.012963 926 3 205 55 155 0.13 0.14 0.15 0.013747 1,057 The sheets may be pressed according to a range of possible pressing regimes; however, we have found that the following schedule of stages can provide very good results. 5 Stages 1 to 3 are conducted using a static pressing station having pressing plates that pressed together by hydraulic piston and cylinder arrangements having a pressing capacity of up to 500 ton per square meter. Stages 4 and 5 are conducted a second static pressing station of the same arrangement having a pressing capacity of up to 100 ton per square meter. An example of a pressuring schedule is outlined below in Table 2. 10 Table 2 Stage 1 * A stack of sheets, separated by water absorbing dividers, is loaded between plates of the press and the press operated to apply 84 tons per sqm over 20 min * The press is then operated to apply pressure of 125 tons per sqm for 10 min. * The press is then operated to apply an increased pressure of 170 tons per sqm for 10 min to produce semi-dewatered sheets. Stage 2 * The stack of semi-dewatered sheets is then subjected to an increasing pressure every 10- 15 min as follows: 210 tons per sqm -- 250 tons per sqm -> 315 tons per sqm -> 360 tons per sqm -> 400 tons per sqm -> 450 tons per sqm. * To obtain optimum dewatering the load has to be kept under a pressure ranging from 450 to 700 tons per sqm for a minimum period of 4 hours. Stage 3 * The dividers are changed with fresh water absorbing dividers and dewatered sheets are moved to a drying press having a pressing capacity of 100 tons per sqm. The sheets are pressed for a period. Stage 4 * The sheets are then removed from the drying press and placed between polymeric dividers without water absorbing dividers for cold ironing that is carried out for a period.

WO 2012/019247 PCT/AU2011/001041 - 18 The pressing stations 60 suitably have hydraulic cylinders and may be used with any one or a combination of mechanisms for enhancing the dewatering effect of the press including the use of the vacuum, heating, microwave drying, heat such as kiln and use of ultraviolet rays to dry the sheets 43 of water. 5 It will be apparent to a person skilled in the art that further variations of the process may or may not involve the additional step of transferring the dewatered assembled/non assembled products into a work station whereby two or more sheets can be laminated together (with or without the use of secondary adhesives) such that the direction of the fibres in at least two adjacent sheets is fully aligned or not aligned in any particular direction; and 10 transferring the assembled sheet/s to a drying station to produce a saleable product. The sheets may also be applied to a substrate such as a medium density fibre board (MDF), timber ply board and alike materials. With this in mind, it will be appreciated that Musa veneer produced using strips removed from the inner core of a banana pseudostem by the method of the present 15 invention may be used for a wide variety of purposes from decorative or functional veneers through to paper products that can be printed on and/or used for wrapping/packaging and other commercial applications which veneer is used in. It will be understood to persons skilled in the art of the invention that many modifications may be made without departing from the spirit and scope of the invention. 20 For example, in the situation in which strips are formed from the entire pseudostem of a banana plant, i.e. the strips include material from the inner core and outer portion, additional adhesives can be added to strips for bonding the strips during the pressing step.

Claims (42)

1. A method of producing a product that can be used as a veneer, the method includes the steps of: slicing a stem of a plant to form strips, the stem is sliced in a longitudinal 5 direction so fibre is oriented longitudinally along the strips, and wherein the strips have a water content of at least 50% by weight; and pressing the strips to expel water from the strips and reduce the water content of the strips to form the product.

2. The method according to claim 1, wherein the plant is of the Musa genus and 10 Musaceae family.

3. The method according to claim 1 or 2, wherein the strips sliced from the stem are longitudinal cross-sections extending along at least part of the length of the stem.

4. The method according to any one of the preceding claims, wherein the pressing step includes pressing the strips to reduce the water content of the strips to less than or 15 equal to 25% by weight, and even more suitably, to a content of less than or equal to 18% by weight.

5. The method according to any one of the preceding claims, wherein the strips, prior to the pressing step, have a water content of equal to or greater than 75% by weight, and suitably have a water content ranging from 90 to 96%. 20

6. The method according to any one of the preceding claims, wherein slicing the stem to form strips includes simultaneously slicing multiple strips from the stem.

7. The method according to any one of the preceding claims, wherein slicing the stem includes advancing the stem in a longitudinal direction of the stem into a set of the blades, and moving the blades in a reciprocating direction transverse to the direction of movement of 25 the stem.

8. The method according to claim 7, wherein the blades each include a tensioned wire that slices the stem.

9. The method according to any one of the preceding claims, wherein the strips may have a thickness ranging from 1.5mm to 6.0 mm, and suitably range from 2.0 to 5.0mm, 30 prior to the pressing step. WO 2012/019247 PCT/AU2011/001041 - 20

10. The method according to any one of the preceding claims, wherein the stem has a more dense inner core and a less dense outer portion, and the method includes a preliminary step of removing the outer portion from the inner core such that the step of slicing the strips includes slicing cross-sections extending longitudinally along the inner core 5 of the stem.

11. The method according to any one of the preceding claims, wherein the stem is a banana pseudostem and the preliminary stem includes removing the outer portion from the stem so as to reveal an outer skin layer that extends about the inner core and separates the inner core from the outer portion of the stem. 10

12. The method according to claim 11, wherein the outer skin layer of the inner core is removed by either one or a combination of: i) concurrently with the outer portion being removed from the stem; ii) from the inner core after the outer portion has been removed, or iii) after the inner core has been sliced into strips by removing the outer skin layer from side edges of the strips. 15

13. The method according to claim 11 or 12, wherein the preliminary step includes cutting away the outer portion from the inner core in a longitudinal direction of the stem or circumferentially about the stem.

14. The method according to any one of claims 10 to 13, wherein the preliminary step includes advancing the stem in a longitudinal direction through an opening that is sized to 20 receive and allow the inner core to pass through the opening and prevent the passage of the outer portion so as to remove the outer portion.

15. The method according to any one of the preceding claims, wherein the step of pressing the strips includes arranging the strips so that the strips at least partially overlap to form a sheet, and the pressing step includes pressing two or more than two strips while the 25 strips are arranged in overlapping relationship.

16. The method according to claim 15, wherein arranging the strips includes locating the strips in two or more layers of which a first array of adjacently arranged strips form a first layer and second array of adjacently arranged strips form a second layer and the layers are overlaid, so as to form a multilayered sheet. 30

17. The method according to claim 16, wherein the longitudinal direction of the strips of one layer are arranged in a lengthwise direction of the sheet and the strips of a second layer are arranged at an angle to the lengthwise direction. WO 2012/019247 PCT/AU2011/001041 - 21

18. The method according to any one of claims 15 to 17, wherein the step of arranging the strips in overlapping relationship to from sheets includes stacking the sheets with a divider located between the sheets.

19. The method according to any one of the preceding claims, wherein the pressing 5 step includes apply a pressure up to or less than 700 tons per square meter to the strips.

20. The method according to claim 19, wherein the pressing step includes applying a pressure to the strips in a plurality of stages in which pressure applied to the strips increases from one stage to the next over at least part of the pressing step.

21. The method according to claim 20, wherein each stage includes pressing batches 10 of sheets stage-wise and in which the change in pressure between the stages ranges from 20 to 150 tons per square meter, and each stage is conducted for a period ranging from 5 to 30 minutes.

22. The method according to claim 21, wherein after the stage-wise increments, the sheets are then subject to a pressure in the range from 500 to 700 tons per square meter for 15 at least 4 hours.

23. The method according to claim 22, wherein after being subjected to a pressure in a range from 500 to 700 tons per square meter for at least 4 hours, the pressing step includes a drying stage in which the sheets are subjected to a pressure in the range of 20 to 200 tons, and suitably 50 to 100 tons per square meter for a total of 5 to 8 hours. 20

24. The method according to any one of claims 15 to 23, wherein water absorbing dividers are located between the sheets during the drying step, and the dividers are changed from 4 to 8 times during the drying step.

25. The method according to any one of the preceding claims, wherein the pressing step includes a finishing stage in which the dividers between the sheets have a polymeric 25 surface in contact with the sheets.

26. The method according to any one of the preceding claims, wherein the method also includes a treatement step in which the strips are treated to alter colouring of the strips.

27. The method according to claim 26, wherein the treatment step includes reducing the brightness of the strips by one or a combination of: exposing the strips to sunlight; 30 exposing the strips to ultraviolet radiation from a lamp; application of an oxidizing agent, WO 2012/019247 PCT/AU2011/001041 - 22 acid, alkali and antioxidants; or allowing the stem to naturally age for a period of from 1 to 21 days after the banana harvesting prior to slicing the stem

28. An apparatus that produces a product including plant material, wherein the apparatus includes: 5 a slicing stage that slices a stem of a plant into multiple strips, the slicing stage slices the stem longitudinally so that fibre of the stem is oriented longitudinally along the strips, and wherein the strips have a water content of at least 50% by weight; and a pressing stage that presses the strips to expel water from the strips and 10 reduces the water content of the strips to form the product.

29. The apparatus according to claim 28, wherein the slicing stage includes a plurality of spaced blades that reciprocate laterally to the direction of movement of the stem which travels in a longitudinal direction through.

30. The apparatus according to claim 29, wherein the blades are in the form of 15 tensioned wires.

31. The apparatus according to claim 29 or 30, wherein the slicing stage has a driving assembly for advancing the stem into the blades, an upstream support located upstream of the blades that supports the stems so as to be oriented in a longitudinal direction toward the blades, a ram for engaging an end of the stem which advances the stem toward the blades, 20 and an actuator that is operable to move the ram forward and back along the guiding structure to advance the stem toward the blades.

32. The apparatus according to claim 31, wherein the slicing stage includes a downstream support that is located downstream of the blades that receives the strips cut from the stem. 25

33. The apparatus according to any one of claims 28 to 32, wherein the pressing stage is a batch press having opposed plates and an actuator operable for moving at least one of the plates toward the other plate so that strips between the plates are pressed therebetween.

34. The apparatus according to any one of claims 28 to 30, including a preliminary 30 stage having an opening through which the stem moves in a longitudinal direction, an outer WO 2012/019247 PCT/AU2011/001041 - 23 portion of the stem is removed from an inner core of the stem as the stem enters and passes through the opening, and the slicing stage removes strips from an inner core of the stem.

35. The apparatus according to any one claims 28 to 33, wherein the apparatus includes a treatment stage that changes the colour of the strips that includes either one or a 5 combination of: i) a bath of chemical agents that are applied to the strips; or ii) a radiation exposure platform on which the strips are exposed to sunlight or iii) ultraviolet light from a lamp or iv) natural ageing of the cores or strips by time.

36. A product that is made according to the method of any one claims 1 to 27.

37. A product that can be used as a veneer, the product including at least one strip 10 sliced in a longitudinal direction of a stem of a plant so that fibre is oriented longitudinally along the strips, and wherein the strips initially having a water content of at least 50% by weight, have been pressed so as to have a reduced water content.

38. The product according to claim 37, wherein the plant is of the Musa genus and of the Musaceae family. 15

39. The product according to claim 37 or 38, wherein the product has a water content ranging up to 20% by weight, and suitably in the range from 8% to 18% by weight.

40. The product according to any one of claims 35 to 39, wherein the product has a thickness in the range of 0.08 mm to 0.50 mm in thickness.

41. The product according to any one of claims 35 to 40, wherein the strips sliced from 20 the stem are longitudinal cross-sections extending along the length of the stem.

42. The product according to any one of claims 35 to 41, wherein the stem is a pseudostem of banana plant which has a dense inner core and less dense outer portion, and the strip is of the inner core and free of less dense material of the outer portion of the pseudostem.