WO2009028925A1

WO2009028925A1 - Multi-layered rice husk composite structural panel board

Info

Publication number: WO2009028925A1
Application number: PCT/MY2007/000062
Authority: WO
Inventors: Hung Weng Ng
Original assignee: Aatomo Board Manufacturing (M) Sdn. Bhd.
Priority date: 2007-08-29
Filing date: 2007-08-29
Publication date: 2009-03-05

Abstract

A multilayered composite structural panel board made from Rice Husks (11 ) that comprises of at least two outer layers of smooth and decorative finish with different thicknesses, shapes, designs, construction and a core layer (80) of a rigid structure that is able to withstand warping, wherein all the layers are so bonded and fused together by an extrusion process as to withstand moisture.

Description

Multi-Layered Rice Husk Composite Structural Panel Board Field of the Invention

The present invention relates generally to composite panel boards and more particularly to the making of composite boards composed of a cellulous product and a thermoplastic material through the extrusion process.

Background of Prior Art

Due to the ever increasing demands of the building, construction and furniture industries, panel boards like plywoods, particle boards, fibre boards are always in short supply. This is further aggravated by the fact that supply of natural woods is fast dwindling, and there is a growing concern to seriously conserve the world's forests, thereby causing the price of wood and wood-based products to increase. . In recent years there is a urgent need to find other materials that can substitute for natural wood in the making of panel boards, especially as the world resources for natural timber is fast depleting everywhere due to the indiscriminate clearing of forests.

As a result of which, in recent years there has been a tremendous interest in searching for synthetic wood composites, and similar wood replacement products of composite materials to substitute for wood and wood-based products in the production of panel boards for the building, construction, furniture and such similar industries.

Such composite panel boards generally display many added advantages as compared to the conventional panel boards made from wood. Besides retaining the qualities of wood, like being easy to be sawed, nailed, turned, fastened and finished, these panel boards lend themselves well to enhanced resistance to moisture, to wear and tear, to splintering, to cracking, to warping as well as resistance to expansion and contraction. Furthermore they can also be made vermin resistant and fungus resistant, besides being water proof and weather proof.

Examples of such products are found in patent US5480602 entitled

"Extruded Particle Board" and the a new manufacturing process is described in patent US6117924 entitled "Extrusion of Synthetic Wood

Material" with US5635123 entitled "Bicomposite Material and Method of

Making" that covers both the invention of a new process as well as a new product, all using a composition of a cellulous product with a thermoplastic material applying an extrusion process through a die yielding a homogenous product that meets all the abovesaid qualities and requirements in one way or another.

However, there a many types of such synthetic wood products and each composition has its own specific characteristics including, but not limited to workability, durability, flexibility, weight, appearance as well as resistance to moisture, to cracking, to splintering, to expansion and contraction, to fungus and discoloration.

A particular composition of a product of this nature may be superior to another composition in one particular aspect, but inferior in respect of another aspect. For instance, a particular synthetic wood composition may be more durable, but lacking in appearance compared to another which may be having the desired appearance yet not so durable or one which is much heavier compared to another which is lighter.

It is difficult and costly to incorporate a sufficient amount of certain composition ingredients throughout a single layered component in order that it may exhibit all the different desirable attributes as abovementioned all in one.

There is therefore a need to have a composite panel board comprising of different layers or ply that possess a combination of some or all of the qualities already enumerated.

This is well illustrated in the case of plywood and the like, where a combination of wood-based products are affixed together to provide an accumulation of the total said attributes, like, for example it provides a more superior panel board that has a strong and durable core layer sandwiched by two outer layers that provide a better finished appearance on their surfaces.

Our present invention provides a composite panel board made from a composition of a cellulose product and a thermoplastic material comprising of at least three or more layers or ply that together form a homogenous whole, that collectively contain all the advantages and characteristics of its individual composite layers.

In patent US 5919574 entitled "Plastic Laminate Structural Board and Method for making same", there is disclosed a composite board that comprises of a variety of layers, with the outer layers providing the smooth and decorative surfaces, and an inner core that provides for strength, durability and lightweight. This particular invention utilizes a process whereby the individual layers are formed separately and then the different layers are joined together by gluing them and pressing the said layers together thereafter. The process is therefore more costly and slower, whilst the product itself is more susceptible to splitting and cracking at the joints.

In a very recent patent US 6579605 entitled "Multilayered

Synthetic Wood Component" the product is a multilayer synthetic wood component comprised of a layer of a first synthetic wood composition that is secured to a layer of a second synthetic wood composition, resulting in a wood component that utilizes the beneficial characteristics of each of the compositions and further, it enables the ingredients of each layer to be tailored to the particular application, thereby reducing costs.

There is, therefore, a need of an improved synthetic wood composite panel board that utilizes a plurality of layers or ply thereby incorporating all the different attributes of the different layers to form one homogenous whole by using cheaper ingredients with a more simplified and more economical methods of manufacture.

Again different materials may be used that may be found to be economical as well as suitable. One such material is Rice Husk, which is cheap and found in plenty full supply in most Asian countries especially in South East Asia.

There have been prior art invention utilizing Rice Hulls as the main ingredient and such inventions are found in Australian Patent No. AU 200014986 entitled "Extrusion of bodies using Rice Hull", where a process of using extrusion is described in the manufacture of cellulose bodies to form panel sheets and boards with Rice Hulls as the main feed material.

However, the invention here describes a process of combining a settable mixture composed of Rice Hulls and a binder and the composition being accelerated by heat and progressively forced through an open ended mould chamber in the from of a die by comprehension means to form a composite panel board.

There is therefore a need to utilize materials that are economical and can produce the required result and are also adaptable to the process of manufacturing the composite panel board comprising of different layers or ply by merely changing the composition of the mixture and the heating temperature to yield different layers with different of characteristics The product is a multilayered synthetic wood component comprised of a layer of a first synthetic wood composition that is secured to a layer of a second synthetic wood composition, resulting in a wood component that utilizes the beneficial characteristic of each of the individual compositions and further, it enables the ingredients of each layer to be tailored to the particular application, thereby reducing costs.

There is, therefore, a need of an improved synthetic wood composite panel board that utilizes a plurality of layers to form one homogenous whole by using cheaper ingredients with a more simplified and more economical method of manufacture. SUMMARY OF THE INVENTION

The prevent invention provides for a composite structural panel board made from Rice Husks combined with a inorganic filler like calcium and a thermoplastic material to form a multilayered panel board with at least two outer skin layers or ply sandwiching a core layer in the middle with the skin layers having a smoother and more decorative finish, wish different thickness, shape, designs and construction whereas the core area is more rigid for resisting warping of the composite board.

The layers are so bonded and fused together by an extrusion process as to withstand moisture. The process begins with a Super Mixer in which the cellulose material in the form of Rice Husks is the thoroughly grinded and dried within the Hopper Dryer, fed with the Super

Mixer along with additives which may be organic fillers, like calcium from the Calcium Tank and thermoplastic material from the plastic tank. Thereafter the composite materials are thoroughly mixed and fed into different Feed Hoppers in accordance to their proportions and combinations, from where they are channeled into their separate

Extruders. In the Extruders, the materials are blended, heated and processed at suitable predetermined speeds and temperatures and are then forced into a Die System which is made up of a plurality of adjustable plates.

The Die System allows the starting materials to bond and form a shaped homogenous product, with the melt streams from each of the Extruders joining in the same Die System to form the different layers of the panel board. The extruded material can then be cooled in a Cooling Chamber and thereafter sent via a Roll Former to the Cutter to be cut to size. Brief Description of the Drawings

A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanied drawings, wherein :-

Figure 1 is a flow chart illustrating the process of the present invention.

Figure 2 illustrates the Die Mould in its various views showing the Die System of the present invention Figure 3 shows the perspective view of the Die Mould of the present invention.

Figure 4 shows the composite board of the preferred embodiment of the present invention with two different variations and designs.

Detailed Description of the Invention The features and other details of the process of the invention will now be more particularly described with reference to the accompanying drawings and pointed out in the claims. The same numeral present in different figures represent the same item. It will be understood that the particular embodiments of the invention are shown by way of illustration and not as a limitation of the invention. The principal features of this invention can be employed in various embodiments without departing from the scope of this invention. Figure.1 shows a flow chart of a co-extrusion process of the present invention where it begins with a Super Mixer (10) in which the cellulose material preferably. Rice Husks (11) coming from a Grinder (5) to a Hopper Dryer (20) in which it is pre-dried and is fed into the said Super Mixer (10) along with the Additives (12) which may be inorganic fillers like e.g. Calcium coming from a Calcium Tank (30) and the thermoplastic material (13) from its Plastic Tank (40).

Thereafter the composite materials are thoroughly mixed and fed into different Feed Hoppers (50) in accordance to their proportions and combinations, from whence they are channeled into their respective Extruders (60a, 60b). In the Extruders (60a, 60b) the composite materials are blended and heated and processed at suitable predetermined speeds and temperatures and then forced into a Die System (70) which is made up of a Die Mould with a plurality of adjustable plates.

The Die System (70) allows the extruded composite materials to bond and form a shaped- homogenous product, with the melt streams from each of the Extruders (60a, 60b) joining into the same Die System (70) to form the different layers of the panel board. The extruded material can then be cooled in a Cooling Chamber (80) and thereafter sent via a Roll Former (90) to a Cutter (100) to be cut to size. The Die System as illustrated in Fig 2 (a) (70) comprises of a small opening (71) situated at the centre to take in the melted material from the Extruder (60) to form the core layer (80) of the composite structural panel board (as shown in Figure 4) with two holes (72, 73) one at the top and the other at the bottom to connect to the Extruder (60) to form the skin layer (81 ) of the composite structural panel board (as shown in Figure 4) as illustrated in Fig 2 (a).

The melted material flows through the Die System (70) along the paths as shown in Fig 2 (b) and Fig 2 (d) to exit at the other end as shown in Fig 2 (c) as a whole unit with a predetermined set width of e.g. 4 feet and thickness of e.g. 6 mm.

Various widths and thicknesses of panel boards and various designs can be achieved by adjusting the plates and the size of the opening (74) at the exit end of the Die System (70) as shown in Fig 2 (c). The extruded material is then fed into a cooling chamber (80) to be cooled down to room temperature and thereafter to be sent via the roller former (90) to a cutter (100) to be then cut into the required lengths. The product extruding from the process will be in one embodiment of the invention, preferably a three-ply composite board comprising of two outer layers of skin (81) with a decorative or ribbed design and / or smoother finish and a core layer (80) of rigid construction being sandwiched in between with all the three layers fused together as illustrated in Figure 4. The present invention has been described in detail. However it is to be understood that the detailed description and the specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the ambit and scope of the invention will become apparent to those skilled in the art from this detailed description.

Claims

1. A multilayered composite structural panel board made from a cellulose material combined with a inorganic filler and a thermoplastic material to form a multilayered panel board with at least two outer skin layers (81) sandwiching a core layer (80) in the middle characterized in that the cellulose material is Rice Husk (1 1) and the skin layers have a smoother and more decorative finish and with different thicknesses, shapes, designs and construction, whereas the core area is more rigid for resisting warping of the composite board wherein all the layers are so bonded and fused together by an extrusion process as to withstand moisture.

2. A multilayered composite structural panel board as claimed in Claim 1 wherein the inorganic filler is calcium

3. A method of making a multilayered composite structural panel board characterized in that the process comprises of :- (i) Mixing a composition of cellulose product like Rice Husk (1 1 ), an additive (12), like calcium and a thermoplastic material (13).

(ii) Feeding the said composition in different proportions into different Extruders (60), one for the skin layers (81 ) and the other for the core layer (80). (iii) Forcing the melted streams from the Extruders (60) out though a Die System (70), wherein the different layers are fused together to from a multi-ply panel board.

(iv) Feeding the extruded material into a Cooling Chamber (80) for cooling down to room temperature and thereafter to a Roll Former (90) and a Cutter ( 100) to be cut to size.