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Title:
REINFORCED WOOD-BASED BOARD AND THE METHOD OF MANUFACTURE OF REINFORCED WOOD-BASED BOARD
Document Type and Number:
WIPO Patent Application WO/2017/195019
Kind Code:
A1
Abstract:
There is provided a reinforced wood-based board and a method of manufacture same from particle boards or from MDF boards or from OSB boards or from plywood or other types of sandwich boards of wood or chips and wood fibres manufactured in a known manner, and a reinforcing layer. The boards are subjected to the reinforcing process by adding at least one reinforcing layer of continuous fibres, wherein the fibres are pre-tensed and in the tensile state they are combined with at least one outer surface of the wood-based board with a binder and the whole is subjected to joining in a known manner in technological lines operating continuously. The method according to the invention provides the possibility of manufacture of reinforced straight/flat boards with increased rigidity, and curved-surface boards, e.g., particularly recommended for the manufacture of slats from reinforced board designed for beds, armchairs etc.

Inventors:
LUTOSTAŃSKI, Stanisław (Biale Osiedle 14, 12-220 Ruciane-Nida, PL)
STARANOWICZ, Janusz (ul. Kielecka 66F, 05-500 Nowa Iwiczna, PL)
Application Number:
IB2017/000534
Publication Date:
November 16, 2017
Filing Date:
May 09, 2017
Export Citation:
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Assignee:
NCT SP. Z O.O. (Tadeusza Kosciuszki 47, 16-400 Suwałki, PL)
International Classes:
B29C70/56; B27N3/00; B27N3/18; B27N7/00; B29C65/00; B32B21/10
Foreign References:
US20100035015A12010-02-11
US20070175583A12007-08-02
GB1326943A1973-08-15
US6174483B12001-01-16
US20100221973A12010-09-02
US20110263174A12011-10-27
DE4324581A11994-09-15
EP0663168A11995-07-19
EP10733692A2010-01-14
EP0830826A21998-03-25
PL176044B11999-03-31
DE4112554C11992-05-14
DE4324581A11994-09-15
Attorney, Agent or Firm:
ŁAZEWSKI, Marek et al. (LDS Łazewski Depo i Wspólnicy sp.k, Okopowa 58/72, 01-042 Warszawa, PL)
Download PDF:
Claims:
Patent claims

Claim 1

A method of manufacture of reinforced wood-based boards from particle boards or from MDF boards or from OSB boards or from plywood or other types of sandwich boards of wood or chips and wood fibres manufactured in a known manner, and a reinforcing layer, characterized in that

the boards are subjected to the reinforcing process by adding at least one reinforcing layer of continuous fibres made of cellulose by viscose method or by use of n-n methylmorpholine oxide or of glass or said continuous fibres are synthetic polymer fibres,

wherein these fibres, prior to being joined with the wood-based board, are subject to pretension in the range of 5 to 90%, preferably 10 to 50% of the tensile strength of these fibres, and

in the tensile state they are combined with at least one outer surface of the wood-based board using a thermo- and / or chemically-setting binder and / or a binder which binds in the physicochemical process, and

the binder is applied onto the core of the board and / or the fibre, and

the whole is subjected to joining treatment in a known continuous method in process lines equipped with hot roll presses or hot belt presses operating continuously.

Claim 2

The method according to claim 1, characterized in that the used binder is made from an amine-formaldehyde condensation resin modified with elasticity agents, preferably etherified melamine resins and / or acrylic dispersions or styrene butadiene latex or poly (vinyl acetate) dispersions added in an amount of 10 to 50% by weight.

Claim 3

The method according to any of the proceeding claims, characterized in that said synthetic polymer fibres are from the group consisting of polyester, polyamide, polypropylene, polyethylene, polyacrylonitrile, poli (vinyl chloride) and carbon fibres.

Claim 4

A reinforced wood-based board comprising a core from particle board or OSB board or MDF board or from plywood or other type of sandwich board of wood or chips and wood fibres and a reinforcing layer, characterized in that

the reinforcing layer is constituted by continuous fibres made from glass or cellulose or from synthetic polymer,

wherein these fibres are tensed in the range of 5 to 90%, preferably 10 to 50% of the tensile strength of these fibres, and

in the tensile state, they are joined with at least one outer surface of the wood-based board using a thermo- and / or chemically-setting binder and / or a binder which binds in the physicochemical process.

Claim 5

A reinforced wood-based board according to claim 4, characterized in that the binder is an amine-formaldehyde condensation resin modified with elasticity agents, preferably etherified melamine resins and / or acrylic dispersions or styrene butadiene latex or poly (vinyl acetate) dispersions in the amount of 10 to 50% by weight.

Claim 6

A reinforced wood-based board according to claim 4 or 5, characterized in that said continuous fibres made from synthetic polymer are from the group consisting of polyester, polyamide, polypropylene, polyethylene, polyacrylonitrile, poli (vinyl chloride) and carbon fibres.

Description:
Title of the Invention

Reinforced wood-based board and method of manufacture of reinforced wood-based board

Technical Field

[0001] This invention relates to a method of manufacture of a reinforced wood-based board and a reinforced wood-based board enabling manufacture furniture elements capable of carrying increased static loads as well as variable dynamic loads.

Background Art

[0002] There are many types of wood-based boards manufactured on the basis of mechanically or thermo-mechanically chipped wood, and subsequently joined together into boards with flat or curved surfaces using thermo- and chemically-setting adhesives. Manufactured boards are used in furniture constructions or in the construction industry where, apart from the aesthetic requirements that they are expected to meet, they are subjected to various static loads such as shelves loaded with books, or dynamic loads as in the case of frames for mattresses in beds, couches, armchairs, etc. Known and commonly used particle boards have this disadvantage that they tend to bend towards the applied load over time. This problem was attempted to be solved by manufacturing of a board having a deliberate curvature in the opposite direction to the applied load. The European patent application EP20100733692 discloses a board comprising three layers, wherein one of the outer layers is thicker than the other, and the tension in the thicker layer is greater than in the first thinner layer, which makes the board convex after pressing. One disadvantage of this solution is that the increase in the resistance to bending of such a board is small, additionally it is difficult to obtain a repetitive curvature of the board and the treatment of such boards is difficult. There is a known method of reinforcing of particle boards by covering a particle board with plywood, whereby the thickness of the plywood glued onto one side and the other is differentiated. A thin veneer or lodicules sandwich board is known joined together in a shaping press to give a specific curvature. Such boards in the form of slats are commonly used as frames for bed mattresses, armchairs, etc. Slats made of boards so shaped also get deformed over time.

[0003] Various solutions have been filed to improve the resilient properties of the profile slats. The European patent application EP 0830826 discloses a method of manufacture a resilient slat from joined veneers in a shaping press in which at the ends of the slat in the middle of its thickness, a cut is applied or no joining is applied at ends between at least two veneer layers thereby resulting in increased rigidity in the middle part of such a slat. When veneers are not joined together, a separating layer can be inserted between said veneers. The layer can be made of paper or plastics sheet, or material applied to the veneer in a liquid state. Alternatively, it can be in powder form.

[0004] A Polish patent description No. 176044 discloses a resilient slat from a sandwich wood joined in a shaping press from veneers, wherein below the neutral zone in the resilient slat, a layer consisting of at least one stripe is symmetrically positioned to the central part of the slat between the veneer strips, which [stripe] is much thinner than the veneer strips and shorter than the resilient slat. The stripes are made of resin impregnated cellulose paper or fibreglass fabric. The length of the inserted reinforcing elements decreases toward the middle of the thickness of the resilient slat.

[0005] A German patent application DE19914112554 discloses a profile board made from chips, wherein at least at the layer subject to tensile there are oriented flat chips with the length of a few centimetres.

[0006] A German patent application DE4324581 Al also discloses a bed frame in which resilient slats are made of wood material in the form of a board of oriented flat chips, the so- called OSB board to which a 1 to 3 mm thick reinforcement layer made of veneer or film or fibreglass is joined.

[0007] The common feature of the aforementioned solutions is that they are based on expensive materials such as veneer for the manufacture of which high quality deciduous wood is required, preferably beech or birch. In addition, the reinforcement material in the form of glass fibre and used in the solution is not biodegradable, and it is difficult to use it because of the irritating effect on human skin during the manufacture, treatment and use of such materials.

[0008] There is a need for developing such a solution that would be deprived of the disadvantages of the hitherto used solutions, and in particular, that would make it possible to produce reinforced wood-based boards from pre-manufactured wood-based boards such as particle board, OSB board, MDF board, plywood or other type of a sandwich board of wood or chips and fibres, and the degree of reinforcement of these boards could be adjusted according to the required application, and the manufacture process of the reinforced board could be carried out continuously with high yields from available raw materials.

Summary of the Invention

[0009] According to the invention, the method of manufacture of a reinforced wood-based board from particle boards or from MDF boards or from OSB boards or from plywood or other type of sandwich boards of wood or chips and wood fibres manufactured according to a known method and a reinforcing layer is characterized in that the boards are subjected to the reinforcing process by adding at least one reinforcing layer of continuous fibres made of cellulose by viscose method or by use of n-n methylmorpholine oxide or of glass or said continuous fibres are synthetic polymer fibres, wherein these fibres, prior to being joined with the wood-based board, are subject to pre-tension in the range of 5 to 90%, preferably 10 to 50% of the tensile strength of these fibres, and in the tensile state they are combined with at least one outer surface of the wood-based board using a thermo- and / or chemically-setting binder or a binder which binds in the physicochemical process, and the binder is applied onto the core of the board and / or the fibres, and the whole is subjected to joining treatment in a known method in process lines equipped with hot roll presses or hot belt presses operating continuously.

[0010] Preferably, the binder is from an amine-formaldehyde condensation resin modified with elasticity agents, preferably etherified melamine resins and / or acrylic dispersions or styrene butadiene latex or poly (vinyl acetate) dispersions added in an amount of 10 to 50% by weight. Even more preferably, said synthetic polymer fibres are from the group consisting of polyester, polyamide, polypropylene, polyethylene, polyacrylonitrile, poli (vinyl chloride) and carbon fibres.

[0011] According to the invention, a reinforced wood-based board comprising a core from particle board or from OSB board or from MDF board or from plywood or other type of sandwich board of wood or chips and wood fibres and a reinforcing layer, is characterized in that the reinforcing layer is constituted by continuous fibres made from glass or cellulose or from synthetic polymer. These fibres are tensed in the range of 5 to 90%, preferably 10 to 50% of the tensile strength of these fibres, and in the tensile state, they are joined with at least one outer surface of the wood-based board using a thermo- and / or chemically-setting binder and / or a binder which binds in the physicochemical process.

[0012] Preferably, the binder is from amine-formaldehyde condensation resin modified with elasticity agents, preferably etherified melamine resins and / or acrylic dispersions or styrene butadiene latex or poly (vinyl acetate) dispersions added in an amount of 10 to 50% by weight. Even more preferably, said continuous fibres made from synthetic polymer are from the group consisting of polyester, polyamide, polypropylene, polyethylene, polyacrylonitrile, poli (vinyl chloride) and carbon fibres.

[0013] The board manufactured in this manner is characterized by increased resistance to bending, and the reinforcement degree of the board depends on the strength of the fibres used, their amount and the degree of fibre tension in the reinforcing layer. [0014] The method according to the invention provides the possibility of manufacture of reinforced straight/flat boards with increased rigidity, and curved-surface boards, e.g., particularly recommended for the manufacture of slats from reinforced board designed for beds, armchairs and similar furniture. By changing the amount of fibre applied and adjusting the tension degree of the fibres, it is possible to adjust initial rigidity of reinforced boards, which is important for the furniture elements subjected to static loads such as shelves loaded with books, heavy vessels, etc., as well as furniture elements subjected to dynamic loads, such as frame elements for beds, armchairs, etc.

[0015] The process of joining the fibre layer with the board core surface can be performed with various binders. There is a great difficulty in binding the fibres with the board core surface because it turned out that hard and rigid binders have been found to damage fibres, and elastic binders fail to meet the requirements because the fibres tend to loose. Surprisingly, binders from the condensing resins satisfy the requirements when the initial strength of the joints is similar to the strength of the fibres in the tensile state. The use of an appropriate modification of the condensation resins, allowing for the formation of resilient joints with initial strength similar to the strength of the fibres in the tensile state, allows for the use of the fibre reinforcing force which decides about board reinforcement.

[0016] An important factor in the choice of binders is joining of the fibre with the surface of the board core so that the resulting joint transfers the load from the tensed fibre without being damaged when loaded with static or dynamic loads when the furniture element works. Another important factor is to ensure proper efficiency of the binding process. The binders from amine formaldehyde condensation resins used in the method, such as urea formaldehyde and melamine urea formaldehyde, modified by elasticity agent, preferably styrene butadiene latex or poly (vinyl acetate) dispersions or etherified melamine resins and acrylate dispersions added in an amount of 10 to 50% by weight accelerate are accelerating setting hardening at elevated temperatures and allow to proceed with the joining process in a continuous manner in process lines equipped with hot roll presses or hot belt presses operating continuously.

[0017] The subject-matter of the invention is illustrated by way of embodiments.

Detailed description of Embodiments of the Invention

Example 1.

[0018] The commercial particle board furniture form piece manufactured using MUF adhesive, 15 mm thick and with density of 700 kg / m 3 , made of one type of chips was coated with a binder made of melamine urea formaldehyde resin mixed with etherified melamine formaldehyde resin in a weight ratio of 1: 4 in the amount of 120 g / m 2 , then to the surface of the particle board coated with the binder cellulose fibre continuous stripes were applied in the amount of 300 g/m 2 obtained by viscose method and they were coated again with the same binder at the amount of 100 g / m 2 .

[0019] Accordingly prepared the furniture form piece was placed in a hydraulic press with hot warming plates and before the press was closed, the protruding ends of the fibre stripes were statically loaded with a load constituting 20% of the fibre tearing force value. The press was subsequently closed and pressure corresponding to 6 kG /cm 2 of board surface was exerted and pressing was performed for 3 minutes at the warming plates temperature of 115 Celsius degrees, subsequently the press was opened and the reinforced particle board was removed, which following conditioning at 20 Celsius degrees, was cut into samples along the stripes of joined fibres. All samples demonstrated deflection of 25 mm / m of the board length, then a bending strength test was performed by loading the board with force from the non-reinforced surface. The results obtained were twice as high as for particle board without the reinforcing layer.

Example 2.

[0020] The procedure was as in Example 1, but melamine-urea-formaldehyde resin was modified using styrene butadiene latex and ammonium nitrate hardening agent was added in the amount of 2% by weight in relation to urea formaldehyde resin. Also, a reinforced board with a curved surface of 25 mm / m was obtained and with doubly increased bending strength.

Example 3.

[0021] T e procedure was as in Example 1, but the reinforcing layer was made on both sides of a particle board. A reinforced board with flat surfaces and doubly increased bending strength was obtained.

Example 4.

[0022] Single-layer particle board having thickness of 15 mm and density of 700 kg / m 3 comprises two reinforcing layers of continuous cellulose fibres manufactured in the process of re-forming of the fibres from the cellulose solution in N-N methylmorpholine oxide arranged in the same direction on one side and the other side of the particle board in an amount of 300 g / m 2 per board surface, tensed to the value of 15% of tensile strength and joined with the surface of the particle board with a binder made from commercially available melamine urea formaldehyde resin, mixed with 30% by weight polyvinyl acetate) dispersion applied onto the board surface and fibres in the total amount of 150 g / m 2 . The manufactured board was characterized by bending strength which was twice as high as that of the particle board which was the core of the manufactured reinforced board.

Example 5.

[0023] A sandwich board consisting of a 15 mm thick and 700 kg / m 3 dense single-layer particle board and two 1.2 mm thick and 950 kg / m 3 dense HDF boards previously joined to the particle board surface and one reinforcing layer of continuous cellulose fibres obtained by viscose method, arranged in the same direction on one side of the sandwich board at the amount of 300 g / m 2 of the board surface, tensed with the force corresponding to 20% of the fibre tear force value, joined with the surface of the sandwich board with a binder made from commercially available urea formaldehyde resin, mixed with styrene butadiene latex in the amount of 45% by weight, applied onto the surface of the sandwich board and fibres in the total amount of 150 g / m 2 . The manufactured board was characterized in that its bending strength was twice as high as the bending strength of the sandwich board constituting the core of the manufactured reinforced board, and it had the board surface curvature of 25 mm / m of the length of the board.

[0024] The process of manufacture of reinforced boards can be carried out periodically or continuously, or both these processes can be combined and complemented. Particularly preferred is the continuous process which consists in applying a continuous fibre layer onto the advancing core of the manufactured reinforced board while simultaneously tensioning the fibres in a controlled fashion and applying the binder, wherein the binder can be applied onto the fibres and / or onto the surface of the core of the reinforced board and dried to remove some water or other solvent from the liquid binder. The fibre layer can be applied onto one or both surfaces of the core of the board in the same amounts or the amount of applied fibres onto one and the other side of the surface can vary significantly.

[0025] For the manufacture process of the reinforced board, it is sufficient to create a continuous fibre reinforcement layer on the surface of the board core. It may prove advisable for the user to further finish the surface of the reinforced board, e.g. by painting, varnishing, coating with an additional decorative layer, e.g. furniture foil. An important requirement for the further finishing process is to ensure that reinforcing layer fibres co-operate properly with the finishing layer. The applied reinforcing layer itself has decorative qualities which can be enhanced by the addition of dyes to fibres or binder, or by applying of a special texture.