WO2010144969A1

WO2010144969A1 - Production of perlite and fiber based composite panel board

Info

Publication number: WO2010144969A1
Application number: PCT/AU2010/000761
Authority: WO
Inventors: Bambang Prasetya; Zaenal Asikin
Original assignee: Eze Board Australia Pty Ltd
Priority date: 2009-06-19
Filing date: 2010-06-18
Publication date: 2010-12-23
Also published as: AU2010262764A1

Abstract

A lignin based modifier is described that may be added to formaldehyde based binder systems such as phenol formaldehyde (PF), urea-formaldehyde (UF), melamine formaldehyde (MF), resorcinol formaldehyde (RF) and/or tannin formaldehyde resins. The lignin based modifier may be included in such binder systems used in the manufacture of composite panel boards such as plywood, hard board, medium density fibreboard (MDF) or particle boards in general. The lignin based modifier may used to improve the performance of the binder system, the performance of the resultant composite panel board and reduce the formaldehyde emissions of the board. The lignin modifier may contain: an acid, a gum rosin, a lignin and either a phenol or a polyethylene glycol. The lignin may be derived from lignocellulose powder.

Description

PRODUCTION OF PERLITE AND FIBER BASED COMPOSITE PANEL BOARD

BACKGROUND OF THE INVENTION

1. Field of the Invention

[0001] The present invention relates to Iignin based modifiers and formaldehyde based resins used in the production of composite panel board that may contain expanded mineral material and biomass materials.

2. Description of the Art

[0002J Composite panel boards such as plywood, hard board, medium density fibreboard (MDF) or particle boards in general may be used in building construction or the lining of various structures or freight containers. In addition such composite material may be used in the manufacture of furniture, for example tables, chairs and cupboards.

[0003] Prior art modifiers to improve the performance of formaldehyde based resins used in the production of composite panel board with biomass materials which may also contain expanded mineral matter have been proposed. However none of the prior art provides an entirely satisfactory solution to the provision of a composite panel board that is of appropriate: strength, fire rating, density, water and humidity resistant, weather resistance, pest and fungal attack resistant, dimensional stability and/or with a low emission of formaldehyde.

SUMMARY OF THE INVENTION

[0004] The present invention aims to provide an alternative Iignin based modifier, for formaldehyde based resins used in the production of composite panel board, which overcomes or ameliorates the disadvantages of the prior art or at least provides a useful choice.

[0005] In one form the invention provides a process for production of a composite panel board. The process includes the steps of: making a mixture of a biomass material and a binder system, forming the mixture into a panel and then hot pressing the panel. Where the binder system includes a formaldehyde based resin and a lignin based modifier. Preferably the formaldehyde based resin may be a phenol formaldehyde, urea formaldehyde, melamine formaldehyde, melamine urea formaldehyde, resorcinol formaldehyde or tannin formaldehyde. The process for producing the lignin based modifier of includes the steps of: making a mixture of an acid, a gum rosin, a powder of a composition at least in part lignin and either phenol or polyethylene glycol and then heating of the mixture under a pressure. Preferably the acid is a strong acid which may include a sulphuric acid or a hydrochloric acid. Optionally the steps for producing the lignin based modifier may include a tannin added to the mixture or associated or within the powder.

[0006] Preferably the process for production of a composite panel board includes the step of adding an expanded mineral material to the mixture of the biomass material and the binder system. By way of example the expanded mineral material may include perlite. Also preferably the biomass material includes at least one of a bamboo fibre, a bagasse fibre, a wood fibre, a bark fibre, fibrous plant matter or a coconut fibre; with a moisture content of less than 10% w/w.

[0007] Optionally the process further includes the steps of mixing the lignin based modifier with the formaldehyde resin and controlling a pH of the binder system. Preferably the pH is controlled to an acidic range. Preferably the binder system is sprayed into or onto the biomass material. Optionally a proportion of the binder material may be used to pre-impregnate the expanded mineral material prior to its addition to the biomass material. Preferably the proportion of lignin based modifier controls, for a composite panel board, one or more of: a strength, a water resistance, a dimensional stability or a formaldehyde emission level.

[0008] In an alternate form, the invention provides a lignin based modifier composition which may be made up of: an acid, a gum rosin, a powder of a composition at least in part lignin and either phenol or polyethylene glycol. Preferably the acid is a strong acid. Preferably the powder is from one or more of wood, bark, coconut shell, Bagasse or other lignocellulose source; for example for wood or bark from one or more shrub or tree species from the genus of Acasia, Albizia, Acasia mangium, Paraserianthes falcataria, Eucalyptus sp. or Pinus sp. Optionally the modifier may further contain a tannin.

[0009] In yet another alternate form, the invention provides a process for production of a lignin based modifier, including the steps of: making a liquid or paste mixture of an acid, a gum rosin, a powder of a composition at least in part lignin and either phenol or polyethylene glycol; and then heating the paste mixture under a pressure. Optionally a tannin may be included in the mixture for the modifier. Preferably if phenol is used the step of premixing the phenol with the sulphuric acid to form a phenol and sulphuric acid solution prior to the step of making the paste mixture may be used.

[0010] In still yet another form, the invention provides a composite panel board mixture of a biomass material and a binder system. Where the binder system may include a formaldehyde based resin and a lignin based modifier. Optionally an expanded mineral material may be added to the mixture. The mixture may then be formed into a panel and the hot pressed to produce a composite panel board.

[0011] In yet another form, the invention provides methods and apparatus for the processing of the biomass materials into a form suitable for composite panel boards.

[0012] Further forms of the invention are as set out in the appended claims and as apparent from the description.

DISCLOSURE OF THE INVENTION

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The description is made with reference to the accompanying drawings; of which:

[0014] FIG 1 is a schematic, side elevation view of a modified crusher/flattener.

[0015] FIG 2 is a schematic, plan elevation view of a modified crusher/flattener. [0016J FIG 3 is a schematic, end elevation view of a modified crusher/flattener.

[0017] FIG 4 is a schematic, side elevation view of an alternate modified crusher/flattener to that shown in FIGS 1, 2 and 3.

[0018] FIG 5 is a schematic, plan elevation view of an alternate modified crusher/flattener to that shown in FIGS 1, 2 and 3.

[0019] FIG 6 is a schematic, end elevation view of an alternate modified crusher/flattener to that shown in FIGS 1, 2 and 3.

[0020] FIG 7 is a schematic, vertical cross-section through a heavily modified mulcher/chipper.

[0021] FIG 8 is a schematic flowchart of a process for making composite panel board.

[0022] FIG 9 is a schematic, perspective, partial end view of composite panel board with a series of recesses in one face.

[0023] FIG 10 is a schematic, perspective, partial end view of two identically recessed panels of FIG 9 joined together to form a hollow core composite panel.

[0024] FIG 11 is a perspective view of an alternate embodiment to FIG 10.

[0025] FIG 12 is schematic, exploded, perspective view of an alternative embodiment of a hollow core composite panel sandwiched between two cladding sheets.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Formaldehyde based resins may be used as a binder when forming composite panel boards such as plywood, hard board, medium density fibreboard (MDF) or particle boards in general. Examples of commercially available formaldehyde based resin binder systems that may be used are: phenol formaldehyde (PF), urea-formaldehyde (UF), melamine formaldehyde (MF), resorcinol formaldehyde (RF) and/or tannin formaldehyde. These binder systems are also available with various formaldehyde emission limits. Lignin Based Modifier

[0027] A lignin based modifier may be added to a formaldehyde based binder system, preferably a PF resin. The lignin based modifier may be included in the binder system to improve the performance of the binder system and the resultant composite panel board. The modifier may contain: an acid, a gum rosin, a lignin and either a phenol or a polyethylene glycol.

[0028] The modifier is made by firstly producing a liquid or paste like mixture of an acid, a gum rosin, a powder source of lignin and either a phenol or a polyethylene glycol. The acid is preferably a strong acid. The source of lignin is preferably a lignocellulose powder which may be obtained, by way of example, from wood, bark, coconut shell or bagasse. It will be readily appreciated that the lignocellulose powder may be a mixture derived from multiple sources and in multiple forms. It will also be readily appreciated by a person skilled in the art that the powder of the source of lignin may also inherently have a proportion of other materials within it, for example: cellulose and mineral matter. The separation or otherwise treatment of these other typical materials in ligno-cellulose sources of lignin is not required for the invention. The proportion of lignin in the powder may preferably be from 25 to 30%. It will be readily appreciated by a person skilled in the art that larger ranges of the proportion of lignin in the powder may be used and still be within the scope of the invention. Other proportions of lignin may be accounted for by appropriately adjusting the proportions of other reactants or components for the lignin based modifier and in the consequent use of the modifier.

[0029] In an alternate embodiment, the source of lignin may include tannin as found in various woods, barks and plant foliage. For example tannin from Acasia mangium, Paraserianthes falcataria, Eucalyptus sp. or Pinus sp. The lignin and a tannin in the lignin based modifier may have a synergistic effect which consequently may improve the degree of polymerisation and strength of the binder system.

[0030] The powder source of lignin is preferably prepared to have a particle and/or fibre size range to pass through sieve mesh (British) of 40 to 80 mesh. Such a sieve mesh range may correspond to a sieve aperture size of approximately 0.3 to 0.6 mm. Powders of different size ranges may be used as selected by a person skilled in the art. [0031] In one example of an advantage, the source of lignin described above is to be contrasted with a traditional source of black liquor lignin from sulphite waste liquors of the pulp and paper industries. Black liquor lignin typically requires to be considerably concentrated by dewatering before it may be used economically as a source of lignin. The powder source of lignin described above requires no such dewatering or concentrating.

[0032] The gum rosin component for the lignin based modifier may be obtained as a gum from pine trees or equivalent. It is preferably prepared as a powder of nominal particle size of 0.2 to 0.5 mm although gum rosin powders of different size ranges may be used as selected by a person skilled in the art. The use of gum rosin in the lignin based modifier improves the water repellence and hydrophobic properties of a composite panel board made using it. The use of the gum, gum rosin also improves the dimensional stability of the board since the board will resist swelling that is due to the absorption of water.

[0033] The phenol or polyethylene glycol (PEG) component is premixed with an acid. Preferably a strong acid may be used. Examples of suitable strong acids are hydrochloric acid HCL and sulphuric acid H₂SO₄, with sulphuric acid being preferable. The proportion of sulphuric acid may be approximately 1 to 3 % v/v (volume/volume) of the preferred phenol or more preferably at approximately 1.8% w/w.

[0034] In one embodiment the phenol and acid may be pre-mixed. In another embodiment the lignin source, gum rosin, phenol and acid may be sequentially added to a pressure reactor, described in detail below, and mixed to form the paste within the pressure reactor.

[0035] The components of phenol, sulphuric acid, gum rosin and lignin source may be mixed together as a paste. The approximate proportions of the components within the paste by weight are: 1 part lignin source powder to phenol (or phenol- sulphuric acid solution) in the range of 4 to 5 parts, or more preferably 5 parts phenol (or phenol-sulphuric acid solution). The gum rosin may be added at 0.5 to 3% w/v (weight/volume) of the phenol-sulphuric acid solution. More preferably the gum rosin may be added at 1% to 3% w/v. More preferably the gum rosin may be added at approximately 0.9% w/w (weight/weight) of the phenol-sulphuric acid solution. [0036] The paste may then be placed (or mixed together) into a pressure reactor which is heated to and maintained within, by way of example, a temperature range of 120° to 16O⁰C for one to two hours with a pressure in the range of one to five atmospheres in response to the increase in temperature and the reactions between the components. Preferably the pressure in the pressure reactor is within the range of 4 to 5 atmospheres. However pressures, temperatures and periods of time within the pressure reactor may be more or less than the example ranges given depending on, for example, the size of the pressure reactor, characteristics and size of the components in the pressure reactor. The paste within the pressure reactor may be mixed during the reaction, either periodically or continuously by rotary, agitation or other suitable mixing techniques.

[0037] In one embodiment a maximum temperature of 12O⁰C may be set for a 200 litre pressure reactor for two hours beginning from when the temperature reaches 100⁰C within the pressure reactor. The pressure reactor may take approximately 1 hour to reach 100⁰C from room temperature. During the two hours the temperature of the pressure reactor may be within the approximate range of 110° to 12O⁰C. After two hours an external water cooler may be used to cool the pressure reactor to 5O⁰C. Continuous stirring at 30 rpm may be used throughout the two hours at 12O⁰C and the subsequent cooling to 5O⁰C.

[0038] After a period in the pressure reactor the resultant liquor of lignin based modifier is recovered to be stored or immediately used. The amount of lignin based modifier that may be made in one or a series of production runs where each batch run may be up to and exceeding 10kg.

[0039] The lignin based modifier produced may have a viscosity in the range of 20 to 100 centipoise (cP) and a shelf life of up to 5 years if stored appropriately. Examples of appropriate storage are the use of a suitable plastic or stainless steel container that is not.in direct sunlight.

Application of Lignin Based Modifier

[0040] In one embodiment the lignin based modifier may be applied to the production of composite panel board. Alternate embodiments of the lignin based modifier may be used in the production of composite material that may be used in the manufacture of furniture, for example tables, chairs and cupboards.

[0041] Advantages that the lignin based modifier may be used to impart to formaldehyde based resins used for composite panel board and composite materials are:

• lower formaldehyde emission levels,

• improved cohesive strength of the resin due to enhanced cross-linking,

• improved adhesive properties for the binder system,

• less resin may be used due to the improved cohesive and adhesive properties of the binder system,

• reduced use of catalysts (or hardeners) for curing the binder system,

• improved water repellence with consequent in improvement in dimensional stability and reduced water absorption of the panel board.

• overall weather resistance is improved, and/or

• improved insect and fungal resistance.

Composite Panel Board

[0042] In one embodiment the lignin based modifier may be used in the production of composite panel board that may be made of biomass materials, expanded mineral matter and a formaldehyde based resin. In the following embodiment phenol formaldehyde (PF) resin is used, however it will be readily appreciated that other formaldehyde based resins may be used instead.

Biomass Materials

[0043] In the present example bamboo fibre and bagasse fibre may be used in the manufacture of composite panel board. However it will be readily appreciated that other biomass materials may also be used if desired in alternate embodiments, for example: wood chip, bark chip, coconut fibre and similar fibrous plant matter. In another example, wood or bark from the Acasia mangium tree may be used.

[0044] Bamboo is a highly fibrous biomass material where the fibres are particularly strong and may be in long continuous lengths. However for bamboo to be applied to composite panel board the fibres may be required to be largely separated and shortened. Obtaining largely separated bamboo fibres may be an arduous task due to the particular properties of this biomass material.

[0045] Bamboo of at least 6 months old, preferably more than 1.5 years, and/or with an inside diameter of greater than 20 mm and/or an outside diameter of greater than 40 mm and/or a wall thickness of less than 20 mm, preferably less than 15 mm, is generally most suitable for harvesting. Bamboo preferably of this age or dimensions may possess suitable fibres and may also be more suitable for processing to separate the fibres. However it will be readily appreciated that the bamboo processing techniques may be adapted to suit bamboo of more mature dimensions or properties. Bamboo of the Gigantola species such as Gigantochloa pseudoarundinacea and Gigantochloa hasskarliana have been found to be suitable as a source of bamboo fibre; however other species of bamboo may also be suitable such as Dendrocalamus asper.

[0046] Other bamboo varieties which may be used are shown in the following table: Bamboo varieties in INDONESIA

[0047] Once harvested the bamboo is preferably processed whilst still "green" or not substantially dried out as being in the green state facilitates processing for the fibres. The harvested bamboo is split length ways into a number of strips or "slats" which may be some metres in length. The number of strips from a length of bamboo may only be two, halving of the bamboo, or with other splitters there may be 3 or more strips produced. The long strips or slats may then be fed into a crusher or flattener which combines further splitting, crushing/flattening to largely separate the bamboo fibres into either separate fibres or fibre bundles.

[0048] FIGS 1 , 2 and 3 are respective side, plan and end elevation views of a modified crusher/flattener 1 10. The modified crusher/flattener 1 10 features a first set of modified rollers 112, 1 14 and a second set of modified rollers 116, 1 18. For each set of rollers the respective gaps 120, 122 between the lower 1 12, 1 16 and upper 114, 118 rollers may be adjusted manually by hand wheels 124, 126. The rollers may each have an arrangement of grooves 128, 130 on the cylindrical surface of the rollers 114, 1 18. The grooves 128, 130 may have a pitch, profile and corresponding alignment to each other to facilitate the processing of the bamboo into largely separated fibres and/or bundles of fibres. In addition the grooves 128 of the first set of rollers 1 12, 114 may be coarser and with a different profile than the grooves 130 of the second set of rollers 1 16, 118 in order to facilitate progressive flattening, crushing, transverse fibre separation and transverse rolling to achieve fibre separation. The arrangement of the sets of rollers and their associated grooves may also be adapted to breaking up the nodes of the bamboo.

[0049] In one embodiment the individual grooves 128 of the first set of rollers 1 12, 114 may have a depth of 3 mm and a width of 10 mm. The individual grooves 130 of the second set of rollers 116, 118 may have a depth of 2 mm and a width of 6 mm. The different groove widths between the two sets of rollers allows for variable offset between ridges and respective grooves between the two sets of rollers so as to improve fibre separation with flattening and crushing.

[0050] In use the slats or strips of bamboo are fed into the gap 120 of the first set of rollers 1 12, 114 in the direction of arrow 132 and along the conveyor bed 134. The sets of rollers 1 12, 1 14 & 1 16, 118 may be typically powered by a.motor. From the first set of rollers 1 12, 1 14 the partially processed bamboo is then fed onwards into the gap 122 of the second set of rollers 1 16, 1 18 for further liberation and/or separation of the fibres. Control of the gaps 120, 122 between the rollers 1 12, 1 14, 116, 118 and/or the rotational speed of the rollers allows for different thicknesses of slats to be processed. Similarly different levels of fibre separation may be obtained by controlling the gap size and roller rotational speed/s.

[0051] FIGS 4, 5 and 6 are respective side, plan and end elevation views of an alternate modified crusher/flattener 410. The alternate crusher 410 features an additional, third set of rollers 416, 418 with a gap 422 between the rollers. The rollers 416, 418 may also have another set of alternate grooves 430 further configured and designed to further process the bamboo fed from the second set of rollers 116, 118 of the alternate crusher 410.

[0052] In yet another embodiment of the modified crusher/flattener, only one set of rollers with grooves may be present. .

[0053] FIG 7 is a vertical cross-section through a heavily modified mulcher/chipper 710 that may be used to cut into lengths the bamboo fibre or fibre bundles from the crusher/flattener. The modified mulcher/chipper 710 may also further liberate / separate the fibres from fibre bundles. In FIG 7 a hopper 712 holds the bamboo fibre (not shown) from the crusher/flattener and presents the fibre to an inlet port 714 of a cutting cavity 716. The cutting cavity 716 features a rotor 718 rotating on an axis 720 within the confining shell 722 of the cutting cavity 716. Each arm of the_^rotor 718 may have a cutting tooth 724 or equivalent tool bit. From the cutting cavity 716 two exhaust ports 726, 728 remove cut fibre from the cutting cavity 716.

[0054] In use fibre passing into the inlet port 714 meets the rapidly rotating rotator 718 with cutting tooth 724. Fibre is cut by the rotating cutting teeth 724 as the fibre enters the cutting cavity 716. A lip 730 of the inlet port 714 may be toughened in order to reduce wear and/or improve the cutting action of an opposing tooth 724 as the tooth sweeps past the lip 730. Fibre rotating about the cutting cavity 716 may be subjected to further cutting and/or fibre separation by the rotary movement of the rotor 718 and/or the cutting teeth 724. Once the fibre has been reduced in length appropriately the cut fibre may be swept out of the cutting cavity 716 via the two exhaust ports 726, 728 and suitably collected.

[0055] In one embodiment the mulcher / chipper may operate in range of 1,750 to 2,200 rpm. [0056] Surprisingly it has been found that sun drying of the bamboo from the crusher / flattener for one day on concrete, prior to presentation to the mulcher/chipper, improves fibre quality and reduces the amount of dust generated. The improved bamboo fibre quality by such an improvement may result in a composite panel board with additional superior properties. In contrast conventional use of mulcher / chippers is to undertake processing of material with a minimum of drying; that is as "green" as practicable.

[0057] Bamboo fibres or fibre bundles by the above process may be produced with a diameter range of 0.1 to 1 mm. The length of the fibres or fibre bundles may be from 5 to 50 mm or more preferably 30 to 40 mm. However it will be readily appreciated that the fibre diameters and length may be varied according to the bamboo processing conditions. Bamboo fibre of different fibre diameter and length ranges may be of an advantage for different composite board applications. For example longer fibre lengths may provide structural performance advantages to the composite panel board. In addition fibre length may have an effect on how well the fibre handles during mixing as described below with respect to FIG 8. Excessively long fibres may have a tendency to ball during mixing.

[0058] The cut bamboo fibre may then be dried to a moisture content of preferably <10% w/w.

[0059] The term "bagasse" fibre may be commonly used to refer to fibrous waste from sugarcane processing as well as similar fibrous waste from other plant matter eg sorghum, sugar beet, sisal, as well as wood fibre, coconut fibre, palm oil plant processing waste, etc. In the composite panel board manufacture described here, sugarcane bagasse fibre has been used, however it will be readily appreciated that fibre from other sources may be readily substituted for the sugarcane bagasse fibre. Bagasse or otherwise fibre may be processed via similar techniques as described above for bamboo fibre or by any other suitable technique.

[0060] Preferably the moisture content of the fibre may be <10% w/w. In addition, by way of example, the fibre length may be from 5 to 40 mm, the fibre diameter range may be from 0.1 to 2 mm or 0.5 to 2 mm. Preferably, the fibre is relatively dust free. Expanded Mineral Matter

[0061] Optionally, expanded mineral matter such as perlite may be included in a composite panel board. Expanded, lightweight porous perlite may be readily prepared by heating to become particles of density 0.1 to 0.2 gem^"3. Typically the particle size range is very broad, with 1 to 5 mm being an example of one size range suitable for composite panel board manufacture.

[0062] Alternatives to perlite include similar glassy highly siliceous volcanic materials such as obsidian and/or synthetic versions such as hollow glass microspheres and other siliceous materials.

[0063] FIG 8 is a flowchart showing an embodiment of the process for making a composite panel board. The acidic lignin based modifier 810 is mixed with the typically alkaline PF resin 812 to form an acidic binder system. The proportion of lignin modifier added may be 2 to 5% w/w of the PF resin. More preferably the lignin modifier may be added at approximately 2.5% w/w. The pH may then be adjusted or controlled to preferably between 4 to 5 by the addition of an alkaline such as an ammonium solution. If the time to mixing the binder with the biomass materials and perlite is to be >60 minutes then the pH may need to be increased (less acidic) in order to increase the working time for the binder system. The pH may also be optimised or controlled to provide the most favourable crosslinking conditions for a particular application.

[0064] After pH adjustment the binder system may be allowed to rest for 10 to 20 minutes. The amount of resting time may depend on: the particular proportion of modifier to resin, the pH and/or the ambient temperature. These resting time variables may also affect the working time for the binder system, for example a >5% w/w of modifier will accelerate setting as will a more acidic pH. In practice the 10 to 20 minutes for the binder to rest is usually accommodated within the overall process.

[0065] Biomass material, which may include bamboo fibre 814 and/or bagasse fibre 816, with perlite 818 as the expanded mineral material may be mixed together in a mixing plant chamber. The mixing used may be a tumbling action. The proportions of the respective biomass material and the perlite being selected depending on the desire performance of the product board. Examples of the proportions which may be used for a particular application area and/or desired performance are described below with respect to Table 1. In the present example equal proportions w/w of bamboo fibre 814, bagasse 816 and perlite 818 may be used. Typically the perlite 818 particles are well dispersed amongst the biomass materials 814, 816 in order to take advantage of the more effective bonding action of the binder system 810, 812 to the biomass materials.

[0066] The binder system 810, 812 may then be applied onto the biomass material 814, 816 and perlite 818 via the use of a spray within the mixing chamber 820. The generic industry term for such a spray mixing being "dousing". The binder is doused into and onto the biomass material and perlite until a proportion of 8 to 20 % w/w of binder to the total of the biomass and perlite is obtained. More preferably a proportion of 8 to 15% w/w or 10 to 12 % w/w may be used and in another embodiment a most preferred proportion may be 10% w/w. The proportion of binder used depending on the biomass material and/or expanded mineral material used, the particular application area and/or the desired performance of the product board. During dousing the binder, biomass materials and perlite may be continuously mixed together, preferably tumbled for at least 5 minutes.

[0067] In an alternate embodiment a proportion of 5 to 30% the binder system 810, 812 may be used to pre-coat and/or pre-impregnate the perlite 818 prior to mixing with the biomass material. The pre-impregnated binder may then be released for binding during the hot pressing step. The use of pre-impregnation of the perlite with the binder system may aid to: reduce the amount of "balling" of the biomass material during mixing, allow an increased proportion of binder system to be used, improve the MOR (modulus of rupture) of the manufactured composite board, reduce the amount of dust from the perlite and reduce swelling when the cured board is exposed to water. More preferably 25% of the binder system may be used to pre- impregnate the perlite.

[0068] The w/w proportion of the cured binder system may be approximately 50% lower due to the loss of water during hot pressing and subsequent conditioning. As a general comment the proportion of cured binder to biomass material may be considerably lower than traditional applications such as Bakelite or other composites. [0069] The contents of the mixing plant chamber 820 may then be transferred to a plate, tray or mould for mat forming 822 the shape for a composite panel board. The formed mat is then hot pressed 824 at a temperature of 140° to 16O⁰C for 5 to 20 minutes at a nominal pressure of 5 MPa (50 atmospheres); the particular conditions being chosen according to the desired performance of the product board. For example the use of higher pressures and longer times for boards that are to be made denser with a higher proportion of the binder; consistent with a higher strength board.

[0070] After hot pressing 824 the resultant board is removed from the hot press and cooled 826. Optionally forced air cooling may be applied. After cooling 826 the composite panel board may trimmed 828 or otherwise finished.

[0071] The boards may then be conditioned 830 for one to four weeks. The conditioning period allows for further curing of the binder system, consequent formaldehyde release, the final strength of the board and any other performance desirables to be attained. Formaldehyde emissions may also be reduced by the formaldehyde reacting with the lignin modifier during hot pressing as well as during the conditioning period.

[0072] The resultant boards typically feature homogenously distributed perlite where each perlite particle is surrounded or encapsulated by the biomass material and the binder system. The biomass materials are typically completely coated in the binder system which also binds the biomass material together.

Proportions of Composite Panel Board Components

[0073] Table 1 provides a number of examples of the proportions of the various components within a composite panel board for various application areas. An increased proportion of bamboo fibre may have a particular advantage in improving the strength and/or flexure of a board. An increased proportion of expanded perlite may have an advantage in improving the properties of heat/thermal and/or sound insulation, fire resistance, termite resistance as well as reducing the density or weight of the board. Bagasse fibre may be a useful material for improving structural properties as well as providing a bulk filling material.

Notes to Table 1 :

• The proportions of bamboo fibre, bagasse fibre and perlite are to their combined total of 100% w/w.

• The binder system is applied as a proportion of the total weight of the bamboo fibre, the bagasse fibre and the perlite. The proportion of binder may be in the range of 8 to 20 % w/w.

• The "Total Ranges" last row of Table 1 expresses the range of percentage proportions that bamboo fibre and perlite may have of the whole, where the bagasse fibre proportion is the balance value to make up 100%. General Properties ^•

[0074] Composite panel board thicknesses of 3 to 50 mm may be readily manufactured. The density of the board may be varied from 0.5 to 1.0 gem^'3 or higher, with more preferably greater than or equal to 0.7 gem^" ; depending on the particular application area. A modulus of rupture (MOR) of at least 46 kgcm^" may be obtained. A compressive strength of at least 16 kgcm^"2 may also be obtained. Acoustic insulation to sound transmission class STC 33dB may be attained for a board. Boards may be produced with a fire resistance exceeding that required in ASTM El 19. Formaldehyde emission may be reduced to at least to E2 classification and further to El and EO classifications.

[0075] Thermal conductivity of 0.1 to 0.13 kcal/m.h.C or 0.15 W/mK may be produced for a composite board. In addition building panels incorporating the composite panel boards may be designed and constructed to achieve a desired insulation or thermal conductivity by the use of reflective foil, sarking, fibreglass batts / marts and the like.

[0076] Termite resistance may be produced to the level where 100% mortality is obtained in 3 weeks. A high resistance to termite attack may be exhibited by the composite boards to the tropical species of the northern Australian giant termite Mastotermes darwiniensis (Froggatt). No attack by termites may be had by the optional inclusion of a pesticide such as Bifenthrin at approximately 0.005% w/w (weight of Bifenthrin to weight of composite panel board).

[0077] The composite panel boards of the invention may be readily suitable for building construction. For example, wall panels may be constructed with the appropriate: thickness, multiple skins (multiple boards) and spacers (between the boards / skins), adhesives and/or fasteners. Similarly suitable floor and ceiling panels may also be designed and constructed

Further Variations to the Process

[0078] The above example has described the use of a PF resin however any number of formaldehyde based resins may be applied as above. For example Urea- Formaldehyde (UF) resin, Melamine Formaldehyde (MF) resin, resorcinol formaldehyde resin or Melamine Urea Formaldehyde (MUF) may be substituted for the PF resin to provide a different emphasis in the various desirable performance values for composite panel board, for example in strength and weather resistance.

[0079] It will be readily appreciated that the substitution of UF, or any other suitable resin as above, for PF may involve some adjustment of process conditions in the manufacture of composite panel board. For example the UF resin may be adjusted initially to a neutral pH and then on addition of the acidic lignin based modifier the necessary acidic conditions for cross linking may be obtained. Controlled crosslinking and setting of the resultant, alternate binder system may be had by careful control of the pH to obtain a satisfactory working time. Alternatively a catalyst of ammonium sulphate at 1 to 5% w/w of the UF resin may be used to control the working time, however with the use of the lignin based modifier it has been found that the use of catalysts for curing is generally much reduced.

[0080] Size segregation of the perlite through the thickness of the board may be manufactured into the board. For example: coarser perlite particles within the core of the board, with finer perlite particles towards the surface of the board. Such a size segregation may allow for the reduction in density (and weight) advantage to be had by using a high proportion w/w of coarse perlite particles in the core whilst maintaining the exterior surface of the board to an appropriate level of hardness, ^• durability, structural strength and surface finish via the use of finer perlite particles. The finer perlite particles in the outer layers may also be in a lower proportion w/w compared with core of the board. In yet another alternate embodiment the core layer of the board may have a considerably higher proportion of perlite in order to improve the fire rating to the composite panel board overall.

[0081] In yet another embodiment, an excess of the powder source of lignin (as described previously above) may also be used so that the excess powder forms a filler within the composite panel board. A filler being useful to improve void filling within the thickness of the composite panel board as well as surface finish of the board. The filler may also provide advantages in the performance of the binder system.

[0082] In another embodiment of the panel forming process, the mat forming 822 and hot pressing 824 may be with the use of moulds that may impart a recess or series of recesses into a face of the panel. FIG 9 is a perspective, partial end view of composite panel board 910 with a series of recesses 912 which have been formed into the panel at mat forming 822 and hot pressing 824. The recesses 912 illustrated have a cross-section which is of a smooth, curved form; however more angular'recess cross- sections with differing dimensions may readily be produced as desired, for example FIGS 11 and 12.

[0083] FIG 10 illustrates a perspective, partial end view of two identically recessed panels 910 joined together to form a hollow core composite panel 1010. The two recessed panels 910 may be joined using the binder system described above or any other, suitable adhesive or fastening system. The recesses 912 in the hollow core panel 1010 form hollow cores 1012 within the hollow panel 1010. Such cores 1012 may be used for services such as electricity, plumbing, telecommunications and the like. Alternatively the cores 1012 may enable the panel 1010 to be lighter without significantly affecting structural strength for particular applications.

[0084] FIG 11 is a perspective view of an alternate embodiment to FIG 10. The alternate composite panel board 1110 features recesses/cores 1112 with 45° side walls 1114. In the example of FIG 11 the example dimensions of the alternate hollow core panel 1110 may be: overall width 1116 of 600 mm, thickness 1118 to a hollow core of 13 mm, height 1120 of a hollow core 15 mm, minimum separation 1122 between cores 1112 of 10 mm, core width 1124 of 63 mm and minimum separation 1126 between a core and an edge of the panel of 50 mm.

[0085] FIG 12 is an exploded perspective view of an alternate hollow core composite panel 1210 sandwiched between two cladding sheets 1214. The cladding sheets 1214 may be applied to the hollow core composite panel 1210, by way of example, to improve the fire rating, surface finish, weather proofing, structural strength or any other desirable property. The cladding sheets 1214 may be applied to both sides of a hollow core 1210 or solid composite panel board or to only one side. The cladding sheets 1214 may be of fibre cement or other sheet like material with desirable properties. The cladding sheet 1214 may attached to the outer surface 1216 of the composite panel by fasteners or adhesives as appropriate to the application area for the final product.

[0086] In the example of FIG 12 the example dimensions of the alternate hollow core panel 1210 with cladding sheets 1214 may be: for the composite panel an overall width 1218 of 600 mm, thickness 1220 to a hollow core of 9 mm, height 1222 of a hollow core 48 mm, minimum separation 1224 between cores 1012, 1112 of 10 mm, core side wall width 1226 of 10 mm, core width 1228 of 40 mm and minimum separation 1230 between a core and an edge of the panel of 60 mm; whilst the cladding sheets 1214 may have a thickness 1232 of 4.5 mm or more with an overall width and length dimensions to suit the composite panel board outer surface 1216. The overall thickness 1234 of the combined composite panel board 1210 with cladding sheets 1214 may be 75 mm, by way of example.

[0087] In yet another embodiment of the panel forming process a sheet of coconut fibre composite material may be applied to a composite panel board in the following fashion. Two coconut fibre composite material sheets may be made according to the process described above for the composite panel board. However coconut fibre with the binder system are only used to form the sheet of coconut fibre composite material. It will be appreciated that other suitable fibre sources may also be used with or in substitution to the coconut fibre. Typically the coconut fibre composite material sheets may have a thickness of 1 mm. Referring to FIG 8, at the mat forming step 822 a sheet of coconut fibre composite material is firstly placed in the plate / tray / mould to be used for mat forming 822. The contents of the mixing chamber 820 may then be transferred onto the first sheet of coconut fibre composite material. A second sheet of coconut fibre composite material may then be placed on top of the mat of material that is to form the sandwiched composite panel board. The resultant three layer board of composite panel board mat sandwiched between two sheets of coconut fibre composite material may then be hot pressed and subsequently processed in a similar fashion to that previously described above.

[0088] This three layer composite board may have an advantage in superior abrasion resistance in such applications as the flooring in freight containers as well as an improved modulus of elasticity and other improved structural properties. In addition the veneer of coconut fibre may considerably improve the resistance of the three layer composite board to weathering in tropical building applications. The particular process of producing the three layer composite board together with the superior bonding internally and between the three layers of composite material providing these advantages. [0089] In yet another alternate embodiment of the composite material used to form panel boards, the composite material may alternatively be moulded into other shapes and then cured appropriately via either heat and/or catalysts. Examples of shapes that may be formed may be: cylinders, beams, pipe-like structures or any irregular or arbitrary shape. Example products which may be formed may be furniture, structural elements other than panels.

[0090] Although the invention has been herein shown and described in what is conceived to be the most practical and preferred embodiments, it is recognized that departures can be made within the scope of the invention, which are not to be limited to the details described herein but are to be accorded the full scope of the appended claims so as to embrace any and all equivalent assemblies, devices and apparatus.

[0091] In this specification, the word "comprising" is to be understood in its "open" sense, that is, in the sense of "including", and thus not limited to its "closed" sense, that is the sense of "consisting only of. A corresponding meaning is to be attributed to the corresponding words "comprise, comprised and comprises" where they appear.

[0092] It will further be understood that any reference herein to known prior art does not, unless the contrary indication appears, constitute an admission that such prior art is commonly known by those skilled in the art to which the invention relates.

Claims

1. A process for production of a composite panel board, including the steps of: making a first mixture of a biomass material and a binder system; forming the first mixture into a panel; and hot pressing the panel; wherein the binder system includes a formaldehyde based resin and a lignin based modifier

2. A process according to claim 1, further including the steps for producing the lignin based modifier of: making a second mixture of an acid, a gum rosin, a powder of a composition at least in part lignin and either phenol or polyethylene glycol; and heating of the second mixture under a pressure.

3. A process according to claim 2, wherein the acid is a strong acid.

4. A process according to claim 3, wherein the strong acid includes a sulphuric acid or a hydrochloric acid.

5. A process according to claim 4, further including a step of: pre-mixing the sulphuric acid with the phenol wherein the proportion of sulphuric acid to the phenol is in a range of 1 to 3% volume/volume.

6. A process according to claim 4 or 5, wherein the proportion of sulphuric acid to the phenol is approximately 1.8% weight/weight.

7. A process according to claim 5 or 6, further including a step of: mixing the gum rosin with the second mixture wherein the proportion of gum rosin to the phenol and sulphuric acid solution is in a range of 0.5 to 3% weight/volume.

8. A process according to claim 7, wherein the proportion of gum rosin to the phenol and sulphuric acid solution is .in a range of 1 to 3% weight/volume.

9. A process according to claim 7, wherein the proportion of gum rosin to the phenol and sulphuric acid solution is approximately 0.9% weight/weight.

10. A process according to any one of claims 2 to 9, wherein the steps for producing the lignin based modifier further include: a tannin in the second mixture.

11. A process according to any one of claims 2 to 10, further including the step of: adding to the second mixture 1 part by weight powder to phenol in a range of 4 to 5 parts by weight.

12. A process according to any one of claims 2 to 10, further including the step of: making the paste mixture in the approximate proportions of 1 part by weight powder to 5 parts by weight phenol.

13. A process according to any preceding claim, further including steps of: mixing the lignin based modifier with the formaldehyde resin; and controlling a pH of the binder system.

14. A process according to claim 13, wherein the proportion of lignin based modifier mixed with the formaldehyde resin is in a range of 2 to 5% weight/weight.

15. A process according to claim 13 or 14, wherein the proportion of lignin based modifier mixed with the formaldehyde resin is approximately 2.5% weight/weight.

16. A process according to any one of claims 13 to 15, further including the step of: controlling the pH to an acidic range.

17. A process according to claim 16, wherein the pH is in a range of 4 to 5.

18. A process according to any one of claims 13 to 17, further including the step of: allowing the binder system to rest for a period of time in a range of 10 to 20 minutes prior to the step of making the first mixture of the biomass material and the binder system

19. A process according to any preceding claim, further including a step of adding an expanded mineral material to the first mixture of the biomass material and the binder system

20. A process according to claim 19, wherein the expanded mineral material includes at least one of perlite, obsidian and siliceous materials.

21. A process according to claim 19 or 20, further including the step of: pre-impregnating the expanded mineral material with a proportion of the binder system prior to the step of adding the expanded mineral material to the first mixture.

22. A process according to claim 21 wherein the expanded mineral material of perlite is pre-impregnated with a proportion of the binder system in a range of 5 to 30%.

23. A process according to claim 21 or 22 wherein the proportion is 25%

24. A process according to any preceding claim, further including the step of: at least one of spraying the binder system into the biomass material and spraying the binder system onto the biomass material.

25. A process according to any one of claims 1 to 24, wherein the proportion of binder system to at least one of the biomass material and the expanded mineral material is in the range of 8 to 20% weight/weight.

26. A process according to any preceding claim, further including the step of: hot pressing in a temperature range of 140° to 16O⁰C.

27. A process according to any preceding claim, further including the step of: hot pressing for a period of time in a range of 5 to 20 minutes

28. A process according to any preceding claim wherein the formaldehyde based resin includes at least one of a phenol formaldehyde, a urea formaldehyde, a melamine formaldehyde, a melamine urea formaldehyde, a resorcinol formaldehyde and a tannin formaldehyde.

29. A process according to any preceding claim wherein the biomass material includes at least one of a bamboo fibre, a bagasse fibre, a wood fibre, a bark fibre a coconut fibre and a fibrous plant matter.

30. A process according to claim 29, further including the step wherein the biomass material is controlled to a moisture content of less than 10% w/w.

31. A process according to claim 29 or 30, further including the step wherein the biomass material fibre is processed to a length in the range of 5 to 50 mm.

32. A process according to any one of claims 29 to 31 , further including the step wherein the biomass material fibres or fibre bundles diameters are processed to be in the range of 0.1 to 2 mm.

33. A process according to claim 29 to 32, further including the step wherein the biomass material fibre is in part at least a bamboo processed to a length in the range of 30 to 40 mm.

34. A process according to any one of claims 29 to 33, further including the step wherein the biomass material fibres or fibre bundles are in at least part a bamboo with diameters processed to be in the range of 0.1 to 1 mm.

35. A process according to any preceding claim, further including the step of: controlling a proportion of the lignin based modifier to the formaldehyde based resin.

36. A process according to claim 35 wherein the proportion of lignin based modifier controls for a composite panel board at least one of: a strength, a water resistance, a dimensional stability, a termite resistance and a formaldehyde emission level.

37. A composite panel board produced by any one of claims 1 to 36.

38. A lignin based modifier composition consisting of: an acid, a gum rosin, a powder of a composition at least in part lignin and either phenol or polyethylene glycol.

39. A lignin based modifier composition according to claim 38, wherein the acid is a strong acid.

40. A lignin based modifier composition according to claim 39 wherein the strong acid includes at least one of a sulphuric acid and a hydrochloric acid.

41. A lignin based modifier composition according to any one of claims 38 to 40 wherein the lignin is from one or more of a wood, a bark, a coconut shell, a Bagasse or a lignocellulose source.

42. A lignin based modifier composition according to any one of claims 38 to 41 wherein the powder is from one or more shrub or tree species from the genus of Acasia, Albizia, Acasia mangium, Paraserianthes falcataria, Eucalyptus sp. or Pinus sp.

43. A lignin based modifier composition according to any one of claims 38 to 42 wherein the proportion of lignin in the powder is in a range of 25 to 30%.

44. A lignin based modifier composition according to any one of claims 38 to 43, further including a tannin.

45. A lignin based modifier composition according to claim 44, wherein the tannin is from one or more of Acasia mangium, Paraserianthes falcataria, Eucalyptus sp. or Pinus sp.

46. A lignin based modifier composition according to any one of claims 38 to 45 wherein the gum rosin is from pine trees.

47. A process for production of a lignin based modifier, including the steps of: making a paste mixture of an acid, a gum rosin, a powder of a composition at least in part lignin and either phenol or polyethylene glycol; and heating the paste mixture under a pressure.

48. A process according to claim 47, wherein the acid is a strong acid.

49. A process according to claim 48, wherein the strong acid includes a sulphuric acid or a hydrochloric acid.

50. A process according to any one of claims' 47 to 49, further including the step of: premixing the phenol with the acid to form a phenol and acid solution prior to the step of making the paste mixture.

51. A process according to claim 50, further including the step of: using a proportion of the sulphuric acid to the phenol in the range of 1 to 3% volume/volume.

52. A process according to claim 50 or 51, wherein the proportion of sulphuric acid to the phenol is approximately 1.8% weight/weight.

53. A process according to any one of claim 50 to 52, further including the step of: adding the gum rosin to the paste mixture in a proportion range of 0.5 to 3% weight/volume of the phenol and sulphuric acid solution.

54. A process according to claim 53, wherein the proportion of gum rosin to the phenol and sulphuric acid solution is in a range of 1 to 3% weight/volume.

55. A process according to claim 53, wherein the proportion of gum rosin to the phenol and sulphuric acid solution is approximately 0.9% weight/weight.

56. A process according to any one of claims 47 to 55, further including the step of: making the paste mixture in the proportions of 1 part by weight powder to phenol in a range of 4 to 5 parts by weight.

57. A process according to any one of claims 47 to 55, further including the step of: making the paste mixture in the approximate proportions of 1 part by weight powder to 5 parts by weight phenol.

58. A process according to any one of claims 47 to 57, wherein the steps for producing the lignin based modifier further includes: a tannin in the mixture.

59. A process according to any one of claims 47 to 58, further including the step of: heating the paste to a temperature in the range of 1 10° to 16O⁰C.

60. A process according to claim 59, wherein the temperature range is 110° to 12O⁰C

61. A process according to any one of claims 47 to 60, further including the step of: heating the paste for a period of time in the range of 1 to 2 hours.

62. . A process according to claim 61, wherein the time is approximately 2 hours.

63. A process according to any one of claims 59 to 62, further including the step of: providing a pressure to the paste mixture in the range of 4 to 5 atmospheres.

64. A lignin based modifier produced by any one of claims 47 to 63.

- 65. A composite panel board comprising: a biomass material and a binder system; wherein the binder system includes a formaldehyde based resin and a lignin based modifier.

66. A composite panel board according to claim 65, wherein the formaldehyde based resin includes at least one of a phenol formaldehyde, a urea formaldehyde, a melamine formaldehyde, a melamine urea formaldehyde, a resorcinol formaldehyde and a tannin formaldehyde.

67. A composite panel board according to claim 65 or 66, wherein the biomass material includes at least one of a bamboo fibre, a bagasse fibre, a wood fibre, a bark fibre, a coconut fibre and a fibrous plant matter.

68. A composite panel board according to any one of claims 65 to 67, wherein the biomass material fibre length is in the range of 5 to 50 mm.

69. A composite panel board according to any one of claims 65 to 68, wherein the biomass material fibres or fibre bundles diameters are in the range of 0.1 to 2 mm.

70. A composite panel board according to any one of claims 65 to 69, wherein the biomass material fibre is in part at least a bamboo with a lengths in the range of 30 to 40 mm.

71. A composite panel board according to any one of claims 65 to 70, wherein the biomass material fibres or fibre bundles are in at least part a bamboo with diameters in the range of 0.1 to 1 mm.

72. A composite panel board according to any one of claims 65 or 71, wherein the bamboo includes at least one of the species of Gigantochloa pseudoarundinacea, Gigantochloa hasskarliana and Dendrocalamus asper.

73. A composite panel board according to any one of claims 65 to 72, further including an expanded mineral material.

74. A composite panel board according to claim 73, wherein the expanded mineral material includes at least one of perlite, obsidian and siliceous materials.

75. A composite panel board according to any one of claims 65 to 74, wherein the proportion of binder system to at least one of the biomass material and the expanded mineral material is in the range of 8 to 20% weight/weight.

76. A composite panel board according to any one of claims 65 to 75 further including a pesticide for termites.

77. A composite panel board according to claim 76, wherein the pesticide is Bifenthrin.

78. A modified crusher or flattener for 'separating in part at least bamboo into individual fibres or fibre bundles comprising: at least one set of two opposed rollers; and grooves on a surface of the rollers; wherein at least one of the grooves, a gap between the rollers and an alignment between the rollers are adapted and controlled to separate bamboo.

79. A modified crusher or flattener according to claim 78, wherein a depth and a width of the grooves are adapted to separate bamboo.

80. A mulcher/chipper adapted to process to biomass material to at least one of fibre bundles and individual fibres.

81. A mulcher/chipper according to claim 80 wherein the biomass material fibre is in part at least a bamboo processed to a length in the range of 30 to 40 mm.

82. A mulcher/chipper according to claim 80 or 81 wherein the biomass material fibres or fibre bundles are in at least part a bamboo with diameters processed to be in the range of 0.1 to 1 mm.

83. A mulcher/chipper according to any one of claim 80 to 82 wherein the bamboo has been pre-processed by the modified crusher or flattener of claims 78 or 79.

84. A process for production of a composite panel board substantially as described herein.

85. A composite panel board substantially as described herein.

86. A lignin based modifier composition substantially as described herein.

87. A process for production of a lignin based modifier substantially as described herein.

88. A modified crusher or flattener substantially as described herein.

89. A mulcher/chipper substantially as described herein.