WO2001081056A1 - Reinforced particle board and method for manufacturing thereof - Google Patents

Reinforced particle board and method for manufacturing thereof Download PDF

Info

Publication number
WO2001081056A1
WO2001081056A1 PCT/HU2001/000051 HU0100051W WO0181056A1 WO 2001081056 A1 WO2001081056 A1 WO 2001081056A1 HU 0100051 W HU0100051 W HU 0100051W WO 0181056 A1 WO0181056 A1 WO 0181056A1
Authority
WO
WIPO (PCT)
Prior art keywords
fibres
fabric sheet
composite layer
particle board
embedded
Prior art date
Application number
PCT/HU2001/000051
Other languages
French (fr)
Inventor
Imre Mura, Jr.
Imre Mura
Original Assignee
Mura Imre Jr
Imre Mura
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Mura Imre Jr, Imre Mura filed Critical Mura Imre Jr
Priority to AU56564/01A priority Critical patent/AU5656401A/en
Publication of WO2001081056A1 publication Critical patent/WO2001081056A1/en

Links

Classifications

    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
    • E04C2/00—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels
    • E04C2/02—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by specified materials
    • E04C2/10—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by specified materials of wood, fibres, chips, vegetable stems, or the like; of plastics; of foamed products
    • E04C2/16—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by specified materials of wood, fibres, chips, vegetable stems, or the like; of plastics; of foamed products of fibres, chips, vegetable stems, or the like
    • E04C2/18—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by specified materials of wood, fibres, chips, vegetable stems, or the like; of plastics; of foamed products of fibres, chips, vegetable stems, or the like with binding wires, reinforcing bars, or the like
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28B1/00—Producing shaped prefabricated articles from the material
    • B28B1/52—Producing shaped prefabricated articles from the material specially adapted for producing articles from mixtures containing fibres, e.g. asbestos cement
    • B28B1/525—Producing shaped prefabricated articles from the material specially adapted for producing articles from mixtures containing fibres, e.g. asbestos cement containing organic fibres, e.g. wood fibres
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28B23/00—Arrangements specially adapted for the production of shaped articles with elements wholly or partly embedded in the moulding material; Production of reinforced objects
    • B28B23/0006—Arrangements specially adapted for the production of shaped articles with elements wholly or partly embedded in the moulding material; Production of reinforced objects the reinforcement consisting of aligned, non-metal reinforcing elements

Definitions

  • the invention relates to a reinforced particle board and to a method for manufacturing thereof.
  • Particle boards and chipboards are widely used in the furniture and construction industry. They are produced by hot pressing from a composite layer comprising plant-origin particles and a binding material.
  • the plant-origin particles can be of wood or annual plants, and as a binding material generally resin or Portland cement is used.
  • the particle boards is the cement-bonded particle board manufactured by a high, for example 0.5 to 5 MPa pressure pressing, which has numerous excellent physical characteristics, for example a high compressive strength, water-proofness, frost resistance and fire resistance. Therefore, this type of particle board could be advantageously used in the construction industry, for example as construction industry formwork, outdoor and indoor coverings, load- bearing walls, floor panels, floor coverings and false ceilings. Unfortunately, the application of these particle boards is limited due to their relatively low bending strength and their low tensile strength measured in the plane of the particle board. Due to the same reason, the construction industry application of other types of particle boards is also restricted.
  • the cement-bonded particle boards are generally manufactured with a thickness of 8 to 32 mm and in different board sizes depending on the actual application.
  • the highest bending strength of currently available cement-bonded particle boards manufactured by high pressure pressing is approx. 9 MPa, and their maximum tensile strength is approximately 3.12 MPa. In practice, this means among other things that thin cement-bonded particle boards can be easily broken or damaged when transported. Therefore, for instance, cement-bonded particle boards of 8 mm thickness are marketed only to a very limited extent.
  • cement-bonded particle boards break easily under impact of a dynamic load perpendicular to their surface, and so, for example, when they are used as a false floor, they must have a thickness of not less than 22 mm. Their application as a false ceiling is also difficult, because due to the reasons mentioned above, suspensions at very short distances are necessary or very thick, heavy weight panels are to be used.
  • a fabric sheet consisting of two extreme fibres and a middle fibre running between them in a zigzag manner is laid in the desired centre zones of the mass, and then the mass including the fabric sheet is shaped as required by a pressing process.
  • the fibres of the fabric are preferably glass fibres, smeared with an adhesive prior to laying.
  • particle boards reinforced with fabric sheets and methods for manufacturing thereof are disclosed in GB 1 601 208 and GB 2 248 246 A.
  • the fabric sheet is formed as a mesh or grid and is embedded substantially in parallel with the composite layer into the composite material of the particle board by means of a pressing process.
  • the fabric sheet is preferably made of glass fibres, carbon fibres, metal fibres or plastic fibres, and between the neighbouring fibres, which can consist of a plurality of elementary fibres, there is a sufficiently large distance for the composite material of the particle board to intrude into the holes of the fabric sheet, thereby enabling appropriate embedding of the fabric sheet into the particle board.
  • This solution is used for example in the case of DUROCKTM cement-bonded particle boards manufactured by the USG Corporation.
  • the reinforcing fabric sheets are made of fibres of one material type, which material is preferably high-tensile and rigid in order to achieve the required strength increase.
  • the rigidity of the fibres results in that at crossings of the fibres or at other meetings of the fibres, for example at snarlings, the fibres exert very high compression load onto each other. This can lead to a fracturing of the fibres and thereby to a drop of the strength of the reinforced particle board. This is why in particle boards pressed at a relatively high, for example 0.5 to 5 MPa pressure, the fabric sheet reinforcement is not used, although reinforcing this type of particle boards would be highly desirable considering their favourable characteristics as listed above.
  • a further object of the invention is to provide a simple and relatively low cost method for manufacturing such fibre reinforced particle boards.
  • the invention is based on the idea that the above disadvantages can be eliminated by using a fabric sheet having first fibres extending substantially in parallel with each other and second fibres connecting the first fibres, wherein the first fibres are fibres increasing the strength of the particle board, for example glass fibres, carbon fibres, kevlar fibres or high-tensile plastic fibres, and the second fibres are of a material softer than that of the first fibres, for example cotton or plastic, so as to reduce or eliminate fracturing of the first fibres at locations where the first fibres and the second fibres are pressed onto each other.
  • first fibres are fibres increasing the strength of the particle board, for example glass fibres, carbon fibres, kevlar fibres or high-tensile plastic fibres
  • the second fibres are of a material softer than that of the first fibres, for example cotton or plastic, so as to reduce or eliminate fracturing of the first fibres at locations where the first fibres and the second fibres are pressed onto each other.
  • the invention is a reinforced particle board formed by pressing of a composite layer comprising plant-origin particles and a binding material, and of a reinforcing fabric sheet embedded into the composite layer substantially in parallel with the composite layer, wherein the fabric sheet has first fibres extending substantially in parallel with each other and second fibres connecting the first fibres.
  • the first fibres are strength- increasing fibres
  • the second fibres are made of a material softer than that of the first fibres so as to reduce fracturing of the first fibres during the pressing at locations where the first fibres and the second fibres are pressed onto each other.
  • the fracturing at fibre crossings can be substantially reduced or eliminated during the manufacturing of the particle board, and thereby the fabric sheet reinforcement becomes applicable also in the case of particle boards produced with a high pressure pressing.
  • the particle boards reinforced with one or more such fabric sheets have increased bending and tensile strength, and therefore the breakage risk is lower at transportation and they can be subjected to higher static and dynamic loads.
  • the first fibres connected with each other by the softer second fibres result in a fabric sheet which can be easily handled, and allow an ordered embedding of the first fibres, thereby making the manufacturing process more simple.
  • the softer second fibres can also contribute to the strength-increase of the particle board.
  • the reinforcing fabric sheet is formed as a grid, wherein the first fibres are arranged in a first direction and the second fibres are arranged substantially in parallel with each other in a second direction being substantially perpendicular to the first direction.
  • the first fibres are made of glass or carbon, they preferably consist of a plurality of elementary fibres.
  • the second fibres can also consist of a plurality of elementary fibres.
  • the inventive fabric sheet can be embedded properly, if the distance between neighbouring fibres is at least 0.5 mm.
  • the first fibres are preferably made of glass fibres, carbon fibres, kevlar fibres or high- tensile plastic fibres, and the second fibres are preferably made of cotton or plastic.
  • the bending strength of the particle board can be increased to a greater extent if the fabric sheet is embedded into the composite layer at a depth smaller than one-third of the thickness of the composite layer, for example at a depth corresponding to the thickness of the fabric sheet.
  • the surface-embedded fabric sheet makes the pattern of the fabric sheet visible on the surface of the reinforced particle board, which facilitates the appropriate positioning of the particle board at the site of installation.
  • a protective layer made of paper can be secured to the particle board on its side provided with the fabric sheet.
  • the fabric sheet can be embedded not only on one side of the composite layer but on both sides or in several layers.
  • the binding material is Portland cement and the particles are pinewood particles.
  • the invention is a method for manufacturing a reinforced particle board comprising the steps of spreading a composite layer comprising plant-origin particles and a binding material, adding a reinforcing fabric sheet to the composite layer, and by pressing the composite layer together with the fabric sheet and thereby introducing the material of the composite layer into holes of the fabric sheet the fabric sheet is embedded into the composite layer, wherein the fabric sheet has first fibres extending substantially in parallel with each other and second fibres connecting the first fibres.
  • fibres increasing the strength of the particle board are used as the first fibres, and the second fibres are of a material softer than that of the first fibres so as to reduce fracturing of the first fibres during the pressing step at locations where the first fibres and the second fibres are pressed onto each other.
  • the inventive method can be carried out simply and cost-efficiently due to the circumstance that the production technology of particle boards allows a relatively simple embedding step of a fabric sheet.
  • the particle board with the fabric sheet form a uniform structure without the need for any adhesive or auxiliary material.
  • a fabric sheet embedded at a relatively small depth under the surface of the particle board increases the bending strength and the tensile strength significantly, while other favourable characteristics of the product remain unchanged.
  • the pressing step is carried out by lower and upper pressure plates, wherein between one of the pressure plates and the composite layer a superficial fabric sheet is placed, and then by pressing the composite layer and the superficial fabric sheet by means of the lower and upper pressure plates the superficial fabric sheet is embedded into the surface of the composite layer.
  • a first layer of the material of the composite layer is spread onto the lower pressure plate, an inner fabric sheet is arranged on the first layer, a second layer of the material of the composite layer is spread onto the inner fabric sheet, and then by pressing the first and second layers and the inner fabric sheet by means of the lower and upper pressure plates the inner fabric sheet is embedded into the composite layer.
  • the fabric sheet embedded inside the composite layer is protected against impacts while transporting or when subjected to loads.
  • the pressing step is carried out at a pressure of 0.5 to 5 MPa, after the pressing step a heat treating step is carried out at 110 to 160 °C for 5 to 10 hours, and after the heat treating step the particle board is conditioned for 10 to 20 days.
  • Figs. 1A to 1C are portions of preferred embodiments of reinforcing fabric sheets according to the invention.
  • Figs. 2 to 4 are schematic three-dimensional views depicting steps of a preferred embodiment of a method according to the invention.
  • Fig. 5 is a perspective view showing an embodiment of the reinforced particle board formed with a surface-embedded fabric sheet
  • Fig. 6 is a perspective view showing an embodiment of the reinforced particle board formed with an inner fabric sheet
  • Fig. 7 is a perspective view showing an embodiment of the reinforced particle board formed with two embedded fabric sheets, and
  • Fig. 8 is a side view showing a reinforced particle board formed with two surface-embedded fabric sheets.
  • Fabric sheets 1a, 1b and 1c are formed as grids and comprise first fibres 2 extending in a first direction in parallel with each other, and second fibres 3 extending substantially perpendicular to the first direction in parallel with each other.
  • fibres 2 are glass fibres, which increase the bending and tensile strength of the particle board in the first direction and which consist of a plurality of elementary fibres.
  • the thickness of fibres 2 is preferably between 0.1 and 10 mm.
  • Fibres 3 are polyester fibres which are softer than glass and deformable, nevertheless they also increase the bending and tensile strength of the particle board in the second direction to a certain extent. Fibres 3 consist of two elementary fibres which embrace the fibres 2 in an alternating manner as shown in the drawings.
  • Fabric sheets 1a, 1b and 1c are preferably formed by applying weft fibres consisting of elementary glass fibres, and warp fibres which are made of polyester.
  • the fabric coming off the loom is placed into a vat containing an appropriate adhesive, for example polyvinylacetate, and after a short drying phase, a fabric formed like a grid with the fibres secured to each other at the crossings is obtained.
  • the fabric is then cut in the desired size and form.
  • fibres 2 and 3 are arranged as a square grid with an equal distance from each other.
  • fibres 2 are rigid enough to enable a less dense arrangement of the crosswise extending fibres 3.
  • fibres 2 are arranged in pairs in the first direction.
  • an appropriate embedding can be achieved by a fabric sheet in which there is at least 0.5 mm distance between the neighbouring fibres.
  • the composite layer can not intrude into the holes of the fabric sheet to the required extent.
  • a superficial fabric sheet 1 is placed on a surface of a lower pressure plate 10 of a flat press as shown in Fig. 2.
  • fabric sheet 1 can be of a type according to any of fabric sheets 1a, 1b or 1c, or fibres 2 can be made for example of kevlar, carbon fibres or high- tensile plastic fibre. Fibres 3 can also be made of cotton, for example.
  • a composite layer 4 comprising Portland cement, pinewood particles, and water- glass solution is spread on fabric sheet 1.
  • a layer consisting of coarser particles is spread between lower and upper layers consisting of finer particles.
  • the composite layer 4 together with the fabric sheet 1 is pressed with a pressure of 0.5 to 5 MPa.
  • the material of the composite layer 4 surrounds the fibres of the fabric sheet, and is introduced into the holes thereof.
  • the fabric sheet is embedded into the surface of the particle board.
  • the softer fibres 3 are deformed or compressed, thereby the more rigid, for example glass fibres 2 are not subjected to fracturing at the crossings.
  • the reinforced particle board is heat treated for 5 to 10 hours at 110 to 160 °C, and then conditioned for 10 to 20 days.
  • the fabric sheet 1 and the particle board form a uniform structure without the need for any adhesive or auxiliary material.
  • the fabric sheet 1 surrounded by the material of the particle board can not be separated from the particle board.
  • Fig. 5 shows a piece of the reinforced particle board produced by the method described above and having a thickness of 12 mm.
  • the reinforced particle board consists of upper and lower layers 20, 22 comprising finer particles and of a middle layer 21 comprising coarser particles.
  • Into the upper layer 20 is the superficial fabric sheet 1 embedded in a way that the material of the particle board totally surrounds it except for the top surface of the fabric sheet 1. Since the top surface of the fabric sheet 1 is not covered by the material of the particle board, the pattern of the fabric sheet 1 is visible on the surface of the particle board and this is extremely advantageous because it facilitates the appropriate positioning of the fibre reinforced particle board.
  • the fibre reinforced particle board according to the invention is to be positioned in a way that the pressure forces normal to its plane effect on the side opposite the side provided with the fabric sheet 1.
  • an inner fabric sheet 1 is embedded into the upper layer 20 of the particle board, at a depth less than one-third of the thickness of the composite layer 4, substantially in a parallel with the composite layer 4. This embodiment is advantageous because the fabric sheet 1 is located protected against mechanical damage in the composite layer 4.
  • the bending and tensile strength is to be increased in both directions of the plane of the particle board, according to the embodiment depicted in Fig. 7, two fabric sheets 1 rotated in relation to each other by 90° can be embedded into the particle board.
  • the fabric sheets 1 are separated from each other by the material of the composite layer 4.
  • the fabric sheets 1 are located as near as possible to the surface of the particle board, preferably they are embedded at a depth smaller than one third of the with of the composite layer 4.
  • a fabric sheet 1 is embedded, wherein the two fabric sheets 1 have respective first fibres 2a and 2b and are rotated in relation to each other by 90°.
  • This embodiment is manufactured in a way that after arranging the lower fabric sheet 1 and spreading the composite layer 4, the upper fabric sheet is placed onto the composite layer 4 and the fabric sheets 1 with the composite layer 4 are pressed together.
  • the two fabric sheets 1 increase the bending and tensile strength of the particle board in both directions.
  • protective layers 30 made of paper are fixed by means of an adhesive, which protective layers 30 are made of cardboard in the depicted embodiment.
  • the protective layers 30 protect the fibres against mechanical damage and form a surface for decoration.
  • the inventive reinforcement increased the maximal bending strength at a load perpendicular to the particle board from 10 MPa to 32 MPa in the direction of the glass fibres 2, and to 16 MPa in the direction of the polyester fibres 3.
  • This enables their use for false ceilings, floor panels, for replacing certain conventional monolithic structures of industrial and agricultural buildings, and for producing finished structural elements.
  • the high-pressure manufactured particle board having a higher strength enables the use of a much thinner board in 50 to 60 % of the current applications. Thereby, the field of application of the particle board can be extended, and - by reducing the thickness - a substantial increase of producing capacity can be achieved, without any additional investment.
  • the fabric sheet can have a pattern different from the above embodiments, for example the strength-increasing fibres 2 can be connected with each other by fibres 3 extending in a zigzag pattern.
  • the particle board can be reinforced on its two sides with fabric sheets having different strength-increasing fibres, wherein the fabric sheet of a higher strength may provide strength against static loads in the installed position, while the fabric sheet of a lower strength gives protection against breakage during transport.

Abstract

A reinforced particle board and a method for manufacturing thereof, wherein the reinforced particle board is formed by pressing of a composite layer (4) comprising plant-origin particles and a binding material, and of a reinforcing fabric sheet embedded into the composite layer (4) substantially in parallel with the composite layer (4), and wherein the fabric sheet has first fibres (2) extending substantially in parallel with each other and second fibres (3) connecting the first fibres (2). The first fibres (2) are strength-increasing fibres, and the second fibres (3) are made of a material softer than that of the first fibres (2) so as to reduce fracturing of the first fibres (2) during the pressing at locations where the first fibres (2) and the second fibres (3) are pressed onto each other.

Description

REINFORCED PARTICLE BOARD AND METHOD FOR MANUFACTURING THEREOF
TECHNICAL FIELD
The invention relates to a reinforced particle board and to a method for manufacturing thereof.
BACKGROUND ART
Particle boards and chipboards are widely used in the furniture and construction industry. They are produced by hot pressing from a composite layer comprising plant-origin particles and a binding material. The plant-origin particles can be of wood or annual plants, and as a binding material generally resin or Portland cement is used.
One type of the particle boards is the cement-bonded particle board manufactured by a high, for example 0.5 to 5 MPa pressure pressing, which has numerous excellent physical characteristics, for example a high compressive strength, water-proofness, frost resistance and fire resistance. Therefore, this type of particle board could be advantageously used in the construction industry, for example as construction industry formwork, outdoor and indoor coverings, load- bearing walls, floor panels, floor coverings and false ceilings. Unfortunately, the application of these particle boards is limited due to their relatively low bending strength and their low tensile strength measured in the plane of the particle board. Due to the same reason, the construction industry application of other types of particle boards is also restricted.
The cement-bonded particle boards are generally manufactured with a thickness of 8 to 32 mm and in different board sizes depending on the actual application. The highest bending strength of currently available cement-bonded particle boards manufactured by high pressure pressing is approx. 9 MPa, and their maximum tensile strength is approximately 3.12 MPa. In practice, this means among other things that thin cement-bonded particle boards can be easily broken or damaged when transported. Therefore, for instance, cement-bonded particle boards of 8 mm thickness are marketed only to a very limited extent. Furthermore, as a result of the low bending strength, cement-bonded particle boards break easily under impact of a dynamic load perpendicular to their surface, and so, for example, when they are used as a false floor, they must have a thickness of not less than 22 mm. Their application as a false ceiling is also difficult, because due to the reasons mentioned above, suspensions at very short distances are necessary or very thick, heavy weight panels are to be used.
It is a known solution that to eliminate the above disadvantages, i.e. to increase the bending strength and tensile strength of particle boards, a fabric sheet made of a fibrous material is embedded into the particle boards. The fabric sheet increases the bending strength of the particle board and the tensile strength in the plane of the particle board in a way that it increases the load-bearing capacity by deforming together with the particle board. Such solution is disclosed, for example, in US 4,430,373. In this known solution a mass consisting of wood particles and a binding material is continuously spread. During this process a fabric sheet consisting of two extreme fibres and a middle fibre running between them in a zigzag manner is laid in the desired centre zones of the mass, and then the mass including the fabric sheet is shaped as required by a pressing process. The fibres of the fabric are preferably glass fibres, smeared with an adhesive prior to laying.
Furthermore, particle boards reinforced with fabric sheets and methods for manufacturing thereof are disclosed in GB 1 601 208 and GB 2 248 246 A. In this known solutions the fabric sheet is formed as a mesh or grid and is embedded substantially in parallel with the composite layer into the composite material of the particle board by means of a pressing process. The fabric sheet is preferably made of glass fibres, carbon fibres, metal fibres or plastic fibres, and between the neighbouring fibres, which can consist of a plurality of elementary fibres, there is a sufficiently large distance for the composite material of the particle board to intrude into the holes of the fabric sheet, thereby enabling appropriate embedding of the fabric sheet into the particle board. This solution is used for example in the case of DUROCK™ cement-bonded particle boards manufactured by the USG Corporation.
A common feature of the above known solutions is that the reinforcing fabric sheets are made of fibres of one material type, which material is preferably high-tensile and rigid in order to achieve the required strength increase. The rigidity of the fibres results in that at crossings of the fibres or at other meetings of the fibres, for example at snarlings, the fibres exert very high compression load onto each other. This can lead to a fracturing of the fibres and thereby to a drop of the strength of the reinforced particle board. This is why in particle boards pressed at a relatively high, for example 0.5 to 5 MPa pressure, the fabric sheet reinforcement is not used, although reinforcing this type of particle boards would be highly desirable considering their favourable characteristics as listed above.
DISCLOSURE OF INVENTION
It is an object of the invention to provide a particle board reinforced with one or more fabric sheets, which - in addition to retaining the advantageous physical characteristics of conventional particle boards - eliminates the above mentioned disadvantages, i.e. can be manufactured substantially without any fracturing or destruction of the fibres of the fabric sheet during the pressing step. A further object of the invention is to provide a simple and relatively low cost method for manufacturing such fibre reinforced particle boards.
The invention is based on the idea that the above disadvantages can be eliminated by using a fabric sheet having first fibres extending substantially in parallel with each other and second fibres connecting the first fibres, wherein the first fibres are fibres increasing the strength of the particle board, for example glass fibres, carbon fibres, kevlar fibres or high-tensile plastic fibres, and the second fibres are of a material softer than that of the first fibres, for example cotton or plastic, so as to reduce or eliminate fracturing of the first fibres at locations where the first fibres and the second fibres are pressed onto each other.
Thus, according to a first aspect, the invention is a reinforced particle board formed by pressing of a composite layer comprising plant-origin particles and a binding material, and of a reinforcing fabric sheet embedded into the composite layer substantially in parallel with the composite layer, wherein the fabric sheet has first fibres extending substantially in parallel with each other and second fibres connecting the first fibres. According to the invention, the first fibres are strength- increasing fibres, and the second fibres are made of a material softer than that of the first fibres so as to reduce fracturing of the first fibres during the pressing at locations where the first fibres and the second fibres are pressed onto each other.
By using an inventive fabric sheet, the fracturing at fibre crossings can be substantially reduced or eliminated during the manufacturing of the particle board, and thereby the fabric sheet reinforcement becomes applicable also in the case of particle boards produced with a high pressure pressing. The particle boards reinforced with one or more such fabric sheets have increased bending and tensile strength, and therefore the breakage risk is lower at transportation and they can be subjected to higher static and dynamic loads. The first fibres connected with each other by the softer second fibres result in a fabric sheet which can be easily handled, and allow an ordered embedding of the first fibres, thereby making the manufacturing process more simple. Of course, the softer second fibres can also contribute to the strength-increase of the particle board.
The manufacturing of the fabric sheet it is more simple, if the reinforcing fabric sheet is formed as a grid, wherein the first fibres are arranged in a first direction and the second fibres are arranged substantially in parallel with each other in a second direction being substantially perpendicular to the first direction. In the case the first fibres are made of glass or carbon, they preferably consist of a plurality of elementary fibres. In the given case the second fibres can also consist of a plurality of elementary fibres. The inventive fabric sheet can be embedded properly, if the distance between neighbouring fibres is at least 0.5 mm. The first fibres are preferably made of glass fibres, carbon fibres, kevlar fibres or high- tensile plastic fibres, and the second fibres are preferably made of cotton or plastic.
The bending strength of the particle board can be increased to a greater extent if the fabric sheet is embedded into the composite layer at a depth smaller than one-third of the thickness of the composite layer, for example at a depth corresponding to the thickness of the fabric sheet. The surface-embedded fabric sheet makes the pattern of the fabric sheet visible on the surface of the reinforced particle board, which facilitates the appropriate positioning of the particle board at the site of installation. In the given case, a protective layer made of paper can be secured to the particle board on its side provided with the fabric sheet.
If the application of particle boards requires an increase of the bending and tensile strength in more than one direction or by a large extent, the fabric sheet can be embedded not only on one side of the composite layer but on both sides or in several layers. Preferably two fabric sheets rotated in relation to each other by 90° are embedded into the composite layer.
In a particularly preferred embodiment the binding material is Portland cement and the particles are pinewood particles.
According to a second aspect, the invention is a method for manufacturing a reinforced particle board comprising the steps of spreading a composite layer comprising plant-origin particles and a binding material, adding a reinforcing fabric sheet to the composite layer, and by pressing the composite layer together with the fabric sheet and thereby introducing the material of the composite layer into holes of the fabric sheet the fabric sheet is embedded into the composite layer, wherein the fabric sheet has first fibres extending substantially in parallel with each other and second fibres connecting the first fibres. According to the invention, fibres increasing the strength of the particle board are used as the first fibres, and the second fibres are of a material softer than that of the first fibres so as to reduce fracturing of the first fibres during the pressing step at locations where the first fibres and the second fibres are pressed onto each other.
The inventive method ,can be carried out simply and cost-efficiently due to the circumstance that the production technology of particle boards allows a relatively simple embedding step of a fabric sheet. At the end of the pressing step the particle board with the fabric sheet form a uniform structure without the need for any adhesive or auxiliary material. A fabric sheet embedded at a relatively small depth under the surface of the particle board increases the bending strength and the tensile strength significantly, while other favourable characteristics of the product remain unchanged. In a preferred embodiment of the invention the pressing step is carried out by lower and upper pressure plates, wherein between one of the pressure plates and the composite layer a superficial fabric sheet is placed, and then by pressing the composite layer and the superficial fabric sheet by means of the lower and upper pressure plates the superficial fabric sheet is embedded into the surface of the composite layer. In the given case, a first layer of the material of the composite layer is spread onto the lower pressure plate, an inner fabric sheet is arranged on the first layer, a second layer of the material of the composite layer is spread onto the inner fabric sheet, and then by pressing the first and second layers and the inner fabric sheet by means of the lower and upper pressure plates the inner fabric sheet is embedded into the composite layer. The fabric sheet embedded inside the composite layer is protected against impacts while transporting or when subjected to loads.
In the method according to the invention preferably Portland cement is used as a binding material and pinewood particles as plant-origin particles, the pressing step is carried out at a pressure of 0.5 to 5 MPa, after the pressing step a heat treating step is carried out at 110 to 160 °C for 5 to 10 hours, and after the heat treating step the particle board is conditioned for 10 to 20 days.
BRIEF DESCRIPTION OF DRAWINGS
The invention will hereinafter be described on the basis of preferred embodiments depicted by the drawings, where
Figs. 1A to 1C are portions of preferred embodiments of reinforcing fabric sheets according to the invention,
Figs. 2 to 4 are schematic three-dimensional views depicting steps of a preferred embodiment of a method according to the invention,
Fig. 5 is a perspective view showing an embodiment of the reinforced particle board formed with a surface-embedded fabric sheet,
Fig. 6 is a perspective view showing an embodiment of the reinforced particle board formed with an inner fabric sheet,
Fig. 7 is a perspective view showing an embodiment of the reinforced particle board formed with two embedded fabric sheets, and
Fig. 8 is a side view showing a reinforced particle board formed with two surface-embedded fabric sheets.
MODES FOR CARRYING OUT THE INVENTION
In Figs. 1A to 1C preferred embodiments of fabric sheets for reinforcing particle boards are shown. Fabric sheets 1a, 1b and 1c are formed as grids and comprise first fibres 2 extending in a first direction in parallel with each other, and second fibres 3 extending substantially perpendicular to the first direction in parallel with each other. In the depicted embodiments fibres 2 are glass fibres, which increase the bending and tensile strength of the particle board in the first direction and which consist of a plurality of elementary fibres. Depending on the given application, the thickness of fibres 2 is preferably between 0.1 and 10 mm. Fibres 3 are polyester fibres which are softer than glass and deformable, nevertheless they also increase the bending and tensile strength of the particle board in the second direction to a certain extent. Fibres 3 consist of two elementary fibres which embrace the fibres 2 in an alternating manner as shown in the drawings.
Fabric sheets 1a, 1b and 1c are preferably formed by applying weft fibres consisting of elementary glass fibres, and warp fibres which are made of polyester. The fabric coming off the loom is placed into a vat containing an appropriate adhesive, for example polyvinylacetate, and after a short drying phase, a fabric formed like a grid with the fibres secured to each other at the crossings is obtained. The fabric is then cut in the desired size and form.
In the fabric sheet 1a fibres 2 and 3 are arranged as a square grid with an equal distance from each other. In the fabric sheet 1b fibres 2 are rigid enough to enable a less dense arrangement of the crosswise extending fibres 3. In the fabric sheet 1 c fibres 2 are arranged in pairs in the first direction.
According to our experiments, an appropriate embedding can be achieved by a fabric sheet in which there is at least 0.5 mm distance between the neighbouring fibres. In case of a smaller distance between neighbouring fibres the composite layer can not intrude into the holes of the fabric sheet to the required extent.
As a first step of a method according to the invention for manufacturing a reinforced cement-bonded particle board, a superficial fabric sheet 1 is placed on a surface of a lower pressure plate 10 of a flat press as shown in Fig. 2. According to the invention, fabric sheet 1 can be of a type according to any of fabric sheets 1a, 1b or 1c, or fibres 2 can be made for example of kevlar, carbon fibres or high- tensile plastic fibre. Fibres 3 can also be made of cotton, for example.
As a next step shown in Fig. 3, in a way and proportion known per se, a composite layer 4 comprising Portland cement, pinewood particles, and water- glass solution is spread on fabric sheet 1. In the course of spreading it is advantageous, if in a manner known per se, a layer consisting of coarser particles is spread between lower and upper layers consisting of finer particles.
Next, as can be seen in Fig. 4, by means of an upper pressure plate 11 of the flat press, the composite layer 4 together with the fabric sheet 1 is pressed with a pressure of 0.5 to 5 MPa. Upon pressing, the material of the composite layer 4 surrounds the fibres of the fabric sheet, and is introduced into the holes thereof. Thus, the fabric sheet is embedded into the surface of the particle board. During the pressing step, at crossings of the fabric sheet according to the invention, the softer fibres 3 are deformed or compressed, thereby the more rigid, for example glass fibres 2 are not subjected to fracturing at the crossings.
Next, the reinforced particle board is heat treated for 5 to 10 hours at 110 to 160 °C, and then conditioned for 10 to 20 days. At the end of the manufacturing process, the fabric sheet 1 and the particle board form a uniform structure without the need for any adhesive or auxiliary material. The fabric sheet 1 surrounded by the material of the particle board can not be separated from the particle board.
Fig. 5 shows a piece of the reinforced particle board produced by the method described above and having a thickness of 12 mm. The reinforced particle board consists of upper and lower layers 20, 22 comprising finer particles and of a middle layer 21 comprising coarser particles. Into the upper layer 20 is the superficial fabric sheet 1 embedded in a way that the material of the particle board totally surrounds it except for the top surface of the fabric sheet 1. Since the top surface of the fabric sheet 1 is not covered by the material of the particle board, the pattern of the fabric sheet 1 is visible on the surface of the particle board and this is extremely advantageous because it facilitates the appropriate positioning of the fibre reinforced particle board. The fibre reinforced particle board according to the invention is to be positioned in a way that the pressure forces normal to its plane effect on the side opposite the side provided with the fabric sheet 1.
For the sake of simplicity, in Figs 6 to 8 fibres 3 are not shown.
In the embodiment shown in Fig. 6, an inner fabric sheet 1 is embedded into the upper layer 20 of the particle board, at a depth less than one-third of the thickness of the composite layer 4, substantially in a parallel with the composite layer 4. This embodiment is advantageous because the fabric sheet 1 is located protected against mechanical damage in the composite layer 4.
If the bending and tensile strength is to be increased in both directions of the plane of the particle board, according to the embodiment depicted in Fig. 7, two fabric sheets 1 rotated in relation to each other by 90° can be embedded into the particle board. For reducing the risk of fracturing of the strength-increasing fibres 2a and 2b, it is to be ensured again that the fabric sheets 1 are separated from each other by the material of the composite layer 4. For increasing the bending strength, it is advantageous if the fabric sheets 1 are located as near as possible to the surface of the particle board, preferably they are embedded at a depth smaller than one third of the with of the composite layer 4.
In the embodiment of the inventive reinforced particle board as shown in Fig. 8, into each of the upper and lower surfaces of the composite layer 4 a fabric sheet 1 is embedded, wherein the two fabric sheets 1 have respective first fibres 2a and 2b and are rotated in relation to each other by 90°. This embodiment is manufactured in a way that after arranging the lower fabric sheet 1 and spreading the composite layer 4, the upper fabric sheet is placed onto the composite layer 4 and the fabric sheets 1 with the composite layer 4 are pressed together. The two fabric sheets 1 increase the bending and tensile strength of the particle board in both directions.
Onto both sides of the reinforced particle board, protective layers 30 made of paper are fixed by means of an adhesive, which protective layers 30 are made of cardboard in the depicted embodiment. The protective layers 30 protect the fibres against mechanical damage and form a surface for decoration.
According to our strength tests, in case of a particle board having a 8 mm thickness the inventive reinforcement increased the maximal bending strength at a load perpendicular to the particle board from 10 MPa to 32 MPa in the direction of the glass fibres 2, and to 16 MPa in the direction of the polyester fibres 3. This enables their use for false ceilings, floor panels, for replacing certain conventional monolithic structures of industrial and agricultural buildings, and for producing finished structural elements. The high-pressure manufactured particle board having a higher strength enables the use of a much thinner board in 50 to 60 % of the current applications. Thereby, the field of application of the particle board can be extended, and - by reducing the thickness - a substantial increase of producing capacity can be achieved, without any additional investment.
For those skilled in the art it is obvious that the embodiments described above are only to be considered as examples, and various modifications and variants can be designed within the scope of the invention defined by the following claims. For example, according to the invention, the above embodiments can be combined as necessary in order to obtain the required strength characteristics. For example, it is possible to apply surface-embedded and inner fabric sheets together, or to embed more than two fabric sheets into the particle board. The increasing of strength by fabric sheets can furthermore be utilised also in other types of particle boards, for example, in those where a resin adhesive is used.
The fabric sheet can have a pattern different from the above embodiments, for example the strength-increasing fibres 2 can be connected with each other by fibres 3 extending in a zigzag pattern. The particle board can be reinforced on its two sides with fabric sheets having different strength-increasing fibres, wherein the fabric sheet of a higher strength may provide strength against static loads in the installed position, while the fabric sheet of a lower strength gives protection against breakage during transport.

Claims

1. A reinforced particle board formed by pressing of a composite layer comprising plant-origin particles and a binding material, and of a reinforcing fabric sheet embedded into the composite layer substantially in parallel with the composite layer, wherein the fabric sheet has first fibres extending substantially in parallel with each other and second fibres connecting the first fibres, characterised in that the first fibres (2, 2a, 2b) are strength-increasing fibres, and the second fibres (3) are made of a material softer than that of the first fibres (2, 2a, 2b) so as to reduce fracturing of the first fibres (2, 2a, 2b) during the pressing at locations where the first fibres (2, 2a, 2b) and the second fibres (3) are pressed onto each other.
2. The particle board according to claim 1 , characterised in that the reinforcing fabric sheet (1, 1a, 1b, 1c) is formed as a grid, wherein the first fibres (2, 2a, 2b) are arranged in a first direction and the second fibres (3) are arranged substantially in parallel with each other in a second direction being substantially perpendicular to the first direction.
3. The particle board according to claim 1 , characterised in that the first fibres (2, 2a, 2b) or the second fibres (3) consist of a plurality of elementary fibres.
4. The particle board according to claim 1 , characterised in that the distance between neighbouring fibres is at least 0.5 mm.
5. The particle board according to claim 1 , characterised in that the first fibres (2, 2a, 2b) are made of glass fibres, carbon fibres, kevlar fibres or high- tensile plastic fibres, and the second fibres (3) are made of cotton or plastic.
6. The particle board according to claim 1 , characterised in that the fabric sheet (1 , 1a, 1b, 1c) is embedded into the composite layer (4) at a depth smaller than one-third of the thickness of the composite layer (4).
7. The particle board according to claim 6, characterised in that the fabric sheet (1, 1a, 1b, 1c) is embedded into the composite layer (4) at a depth corresponding to the thickness of the fabric sheet (1 , 1a, 1 b, 1c).
8. The particle board according to claim 1 , characterised in that a number of fabric sheets (1 , 1a, 1b, 1c) are embedded, wherein the embedded fabric sheets (1 , 1a, 1b, 1c) are separated from each other by the material of the composite layer (4).
9. The particle board according to claim 8, characterised in that two fabric sheets (1 , 1a, 1 b, 1c) rotated in relation to each other by 90° are embedded into the composite layer (4).
10. The particle board according to claim 1 , characterised in that the binding material is Portland cement and the particles are pinewood particles.
11. The particle board according to claim 7, characterised in that a protective layer (30) made of paper is secured to the particle board on its side provided with the fabric sheet (1, 1a, 1b, 1c).
12. A method for manufacturing a reinforced particle board comprising the steps of spreading a composite layer comprising plant-origin particles and a binding material, adding a reinforcing fabric sheet to the composite layer, and by pressing the composite layer together with the fabric sheet and thereby introducing the material of the composite layer into holes of the fabric sheet the fabric sheet is embedded into the composite layer, wherein the fabric sheet has first fibres extending substantially in parallel with each other and second fibres connecting the first fibres, characterised in that fibres increasing the strength of the particle board are used as the first fibres, and the second fibres are of a material softer than that of the first fibres so as to reduce fracturing of the first fibres during the pressing step at locations where the first fibres and the second fibres are pressed onto each other.
13. The method according to claim 12, characterised in that the reinforcing fabric sheet is formed as a grid, wherein the first fibres are arranged in a first direction and the second fibres are arranged substantially in parallel with each other in a second direction being substantially perpendicular to the first direction.
14. The method according to claim 12, characterised in that the first fibres or the second fibres consist of a plurality of elementary fibres.
15. The method according to claim 12, characterised in that the distance between neighbouring fibres is at least 0.5 mm.
16. The method according to claim 12, characterised in that the first fibres are made of glass fibres, carbon fibres, kevlar fibres or high-tensile plastic fibres, and the second fibres are made of cotton or plastic.
17. The method according to claim 12, characterised in that the pressing step is carried out by lower and upper pressure plates, wherein between one of the pressure plates and the composite layer a superficial fabric sheet is placed, and then by pressing the composite layer and the superficial fabric sheet by means of the lower and upper pressure plates the superficial fabric sheet is embedded into the surface of the composite layer.
18. The method according to claim 12, characterised in that the pressing step is carried out by lower and upper pressure plates, wherein a first layer of the material of the composite layer is spread onto the lower pressure plate, an inner fabric sheet is arranged on the first layer, a second layer of the material of the composite layer is spread onto the inner fabric sheet, and then by pressing the first and second layers and the inner fabric sheet by means of the lower and upper pressure plates the inner fabric sheet is embedded into the composite layer.
19. The method according to claim 18, characterised in that the fabric sheet is embedded into the composite layer at a depth smaller than one-third of the thickness of the composite layer.
20. The method according to claim 17 or claim 18, characterised in that a number of fabric sheets are embedded, wherein the embedded fabric sheets are separated from each other by the material of the composite layer.
21. The method according to claim 20, characterised in that two fabric sheets rotated in relation to each other by 90° are embedded into the composite layer.
22. The method according to claim 12, characterised by using Portland cement as a binding material and pinewood particles as plant-origin particles, wherein the pressing step is carried out at a pressure of 0.5 to 5 MPa, after the pressing step a heat treating step is carried out at 110 to 160 °C for 5 to 10 hours, and after the heat treating step the particle board is conditioned for 10 to 20 days.
23. The method according to claim 17, characterised by securing a protective layer made of paper to the particle board on its side provided with the fabric sheet.
PCT/HU2001/000051 2000-04-27 2001-04-25 Reinforced particle board and method for manufacturing thereof WO2001081056A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU56564/01A AU5656401A (en) 2000-04-27 2001-04-25 Reinforced particle board and method for manufacturing thereof

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
HU0001687A HU223178B1 (en) 2000-04-27 2000-04-27 Chipboard reinforced by web-plate and method for making thereof
HUP0001687 2000-04-27

Publications (1)

Publication Number Publication Date
WO2001081056A1 true WO2001081056A1 (en) 2001-11-01

Family

ID=89978295

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/HU2001/000051 WO2001081056A1 (en) 2000-04-27 2001-04-25 Reinforced particle board and method for manufacturing thereof

Country Status (3)

Country Link
AU (1) AU5656401A (en)
HU (1) HU223178B1 (en)
WO (1) WO2001081056A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2588311B2 (en) † 2010-06-30 2020-03-25 Unilin, BVBA A panel comprising a polymeric composite layer and a reinforcement layer
US11597819B2 (en) 2018-12-24 2023-03-07 Sai Cycle Limited Materials comprising textile debris and latex based binder

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1653161A1 (en) * 1966-05-21 1971-01-21 Friedrich Bilger Reinforcement of wood pulp boards as well as pressed boards and molded parts with wood components
GB1592266A (en) * 1978-05-24 1981-07-01 Marley Trident Ltd Building slabs
GB1601208A (en) 1978-05-23 1981-10-28 Torvale Holdings Ltd Woodwool slabs
US4430373A (en) 1980-12-05 1984-02-07 Lars Hammarberg Reinforced beam section and a method of producing it
EP0203803A1 (en) * 1985-05-30 1986-12-03 Composite Developments Limited Reinforced resinous material
GB2201175A (en) * 1986-06-10 1988-08-24 Stramit Ind Compressed straw panels with paper facing
GB2248246A (en) 1990-09-14 1992-04-01 Furniture Ind Res Ass Reinforced fiberboard
DE4214335A1 (en) * 1992-05-04 1993-11-11 Helmut Meister Process for producing a lightweight component in the form of a plate or cuboid

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1653161A1 (en) * 1966-05-21 1971-01-21 Friedrich Bilger Reinforcement of wood pulp boards as well as pressed boards and molded parts with wood components
GB1601208A (en) 1978-05-23 1981-10-28 Torvale Holdings Ltd Woodwool slabs
GB1592266A (en) * 1978-05-24 1981-07-01 Marley Trident Ltd Building slabs
US4430373A (en) 1980-12-05 1984-02-07 Lars Hammarberg Reinforced beam section and a method of producing it
EP0203803A1 (en) * 1985-05-30 1986-12-03 Composite Developments Limited Reinforced resinous material
GB2201175A (en) * 1986-06-10 1988-08-24 Stramit Ind Compressed straw panels with paper facing
GB2248246A (en) 1990-09-14 1992-04-01 Furniture Ind Res Ass Reinforced fiberboard
DE4214335A1 (en) * 1992-05-04 1993-11-11 Helmut Meister Process for producing a lightweight component in the form of a plate or cuboid

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2588311B2 (en) † 2010-06-30 2020-03-25 Unilin, BVBA A panel comprising a polymeric composite layer and a reinforcement layer
US11597819B2 (en) 2018-12-24 2023-03-07 Sai Cycle Limited Materials comprising textile debris and latex based binder

Also Published As

Publication number Publication date
HU0001687D0 (en) 2000-06-28
HUP0001687A2 (en) 2002-02-28
HU223178B1 (en) 2004-03-29
AU5656401A (en) 2001-11-07

Similar Documents

Publication Publication Date Title
US8034428B2 (en) Reinforced sandwich structure
CA1254496A (en) Fabric reinforced cement structure
US7910193B2 (en) Three-dimensional auxetic structures and applications thereof
CA2513934A1 (en) Textile reinforced wallboard
EP2952650B1 (en) Construction element for raised floors and the like and manufacturing method
CN102232022A (en) Waved wood assembly and method of making same
CN111806002A (en) Composite board made of wood material
US20020141933A1 (en) Graphite structure with increased flexibility
EA000961B1 (en) Method of pressing of sandwich panels
WO2001081056A1 (en) Reinforced particle board and method for manufacturing thereof
US4619857A (en) Thin walled shaped body and method of producing same
SK122694A3 (en) Mineral wool board
KR102138849B1 (en) Textile fabric for seismic reinforcing of a structure and structural seismic reinforcement method
EP1893404B1 (en) Fire protection element, process for manufacturing thereof and use thereof
EP1122373B1 (en) Manufacturing process of an insulating material with mineral fibres
EP1395719A1 (en) Flat or flat inclined roof construction and associated insulating element
KR100264137B1 (en) Fabric sheet
WO2013114386A1 (en) 3d fiber composite
EP3628481B1 (en) A sandwich panel
WO1982001849A1 (en) Reinforced wood particle board and a method of producing it
PL181096B1 (en) Insulating board made of mineral wool and method of making same
KR100424892B1 (en) Two Fold Floor Material and Manufacturing Method Thereof
CZ36124U1 (en) Wood-based sandwich board with textile reinforcement layers
CZ35616U1 (en) Wood-based sandwich board, with higher resistance to sagging
CN111485672A (en) Parallel chord wood truss and manufacturing method thereof

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BY BZ CA CH CN CR CU CZ DE DK DM DZ EE ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NO NZ PL PT RO RU SD SE SG SI SK SL TJ TM TR TT TZ UA UG US UZ VN YU ZA ZW

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): GH GM KE LS MW MZ SD SL SZ TZ UG ZW AM AZ BY KG KZ MD RU TJ TM AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE TR BF BJ CF CG CI CM GA GN GW ML MR NE SN TD TG

DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
121 Ep: the epo has been informed by wipo that ep was designated in this application
122 Ep: pct application non-entry in european phase
NENP Non-entry into the national phase

Ref country code: JP