Flexible natural wood thin board

Abstract

To provide a flexible natural wood thin plate having beautiful grain, hardly scratched on the surface, and not cracked even when bent 180°. [Solution] The bent flexible thin natural wood board is made using a super-finishing planer and has a thickness of 0.05 mm or more and 0.3 mm or less. A polypropylene film, which is a thermoplastic resin film, is bonded to both sides of the natural wood board using a polyolefin adhesive, and further, after the polypropylene film is bonded to both sides of the natural wood board, a cloth is attached to one side using a double-sided tape adhesive or the like.

Description

[Technical Field]

[0001] The present invention relates to a flexible bent thin board made of natural wood. [Background technology]

[0002] Solid wood is often used for furniture (tables, chairs, etc.), residential flooring (flooring), interior and structural materials. After being cut down from the mountains, solid wood is dried and processed before being used for furniture such as tables and chairs, and for residential interior and structural materials. The advantages of solid wood are its extremely low thermal conductivity, which protects living spaces from heat and cold, and although it scratches easily, it has an excellent texture to the touch and a pleasant scent. Furthermore, the beautiful grain and contrasting colors of solid wood enhance the design and aesthetic appeal of furniture and other products, and if it does get scratched, the surface can be scraped off and restored to a beautiful state. The disadvantages are that it shrinks and expands with changes in humidity and temperature, and its physical properties vary depending on the sapwood and heartwood.

[0003] While many solid wood planks have beautiful grain, they can warp, distort, or crack due to changes in humidity and temperature, as well as aging. Solid wood planks are also expensive. Therefore, by using plywood or other woods that are less prone to warping or are inexpensive as the base material (basic material), and then applying a thin veneer (semi-finished wood) to the surface, it is possible to create a material that is physically and visually superior and less expensive than solid wood planks. There are two types of wood grain: straight grain and cross grain. Straight grain is the parallel grain that appears when a log is split into four (like an orange split). It is less likely to warp or split when dried, and is less likely to warp or split than cross grain. However, straight grain cutting restricts the board width and leaves some wood unsawn, resulting in a low yield. The straight grain of natural wood that is hundreds of years old creates a very calm atmosphere. In addition to being used as decorative material and framing material, it is also used by joining together the surface of interior doors and countertops.

[0004] The plank grain appears when the log is sawn away from the center. The grain is mountain-shaped or bamboo-shoot shaped, and the grain curves randomly, with no two pieces of wood having the same grain. Because it is unique, it is often used to bring out the characteristics of wood. The shrinkage caused by drying is greater on the surface of the wood (the side closest to the bark) than on the back (the side farther from the bark), so the wood warps towards the surface. It is used for the front of alcove pillars, decorative pillars, and when joined together, as table tops.

[0005] As prior art, a tool using a thin natural wood board material has been devised in which a softener is impregnated on the front and / or back of the thin natural wood board material to make it flexible, and an elastic material layer is formed on the back of the thin natural wood board material (Patent Document 1). The natural wood thin board material is a thin board made by slicing softwood or hardwood such as cedar or cypress into 0.1 to 0.2 mm pieces, the softener is a mixture of styrene-acrylic copolymer resin emulsion and acrylic copolymer resin emulsion in a weight ratio of 5:1 to 1:1, and the elastic material is a nonwoven fabric, mesh material sheet, and foam sheet, which are adhered in that order to the backside of the natural wood thin board material. A backing material is also adhered to the backside of the elastic material. The softener is applied to the wood, but it is thought that it does not easily penetrate into the natural wood veneer material and may bleed out.

[0006] A composite material and a manufacturing method thereof have been invented in which highly flexible synthetic resin is impregnated into wood by vacuum or vacuum pressure, and then a backing material is attached, allowing for curved surface processing and punching (Patent Document 2). Unsaturated polyester or urethane resin is impregnated into a thin plate of 0.1 mm to 3.0 mm by vacuum or vacuum pressure, and then heat is applied to cause the reaction to harden. Equipment is required to impregnate synthetic resin into wood under vacuum or vacuum pressure.

[0007] A decorative sheet has been invented (Patent Document 3), which comprises a flexible substrate such as felt, onto which a thin natural wood board is bonded, and the surface of the thin natural wood board is coated with a flexible transparent resin that can follow a 180° bend. The thickness of the thin board is 0.3 to 0.6 mm, the bonding is via a urea-containing adhesive, and the flexible transparent resin is a mixture of a solvent-containing acrylic resin and a solvent-containing isocyanate compound in a solvent ratio of 5:1 to 1:3. Some solvents and chemicals used in flexible transparent resins are harmful to the human body and must be handled with care.

[0008] In chopstick cases and the like for eating utensils made from thin wooden boards, eating utensils using thin wooden boards use thin boards with a natural wood-like surface adhesively coated on one or both sides of a thin wooden board made of softwood such as Japanese cypress and having a thickness of 0.1 to 1 mm, with a polyolefin film, and the adhesive for the film is an ethylene-vinyl acetate copolymer or polysaccharide. The chopstick cases for eating utensils are foldable bags made from a single rectangular flat board, and are chopstick tip bag-like covers, and are bonded with adhesive at the two vertical and bottom edges of a rectangular bag-like container made from a single thin board, i.e., a chopstick case has been devised in which a rectangular thin board is folded in half into an elongated shape and the vertical and bottom sides are glued together (Patent Document 4). This device is used by folding a thin plate in half, as shown in the figure, i.e. the plate is split but remains in shape thanks to the adhesive coating of the film. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Publication No. 3062661 [Patent Document 2] Japanese Patent Application Publication No. 10-113906 [Patent Document 3] Japanese Patent Application Laid-Open No. 2001-347608 [Patent Document 4] Japanese Patent Application Laid-Open No. 2006-176730 Summary of the Invention [Problem to be solved by the invention]

[0010] Materials using thin natural wood boards are required to have beautiful wood grain surfaces, bend flexible thin boards that are resistant to scratches and do not crack when bent.

[0011] A tool using a thin natural wood board material has been devised, in which a softening agent is impregnated on the front and / or back of the thin natural wood board material to make it flexible, and an elastic material layer is formed on the back of the thin natural wood board material. The natural wood thin board material is a thin board made by slicing softwood or hardwood such as cedar or cypress into 0.1 to 0.2 mm pieces, the softener is a mixture of styrene-acrylic copolymer resin emulsion and acrylic copolymer resin emulsion in a weight ratio of 5:1 to 1:1, and the elastic material is a nonwoven fabric, mesh material sheet, and foam sheet, which are adhered in that order to the backside of the natural wood thin board material. A backing material is also adhered to the backside of the elastic material. The softener is applied to the wood, but it is thought that it does not easily penetrate into the natural wood veneer material and may bleed out.

[0012] A composite material and manufacturing method have been invented in which highly flexible synthetic resin is impregnated into wood using vacuum or vacuum pressure, and then a backing material is attached, allowing for curved and punched processing.Unsaturated polyester or urethane resin is impregnated into a thin plate of 0.1 to 3.0 mm using vacuum or vacuum pressure, and then heat is applied to cause the reaction to harden. Equipment is required to impregnate synthetic resin into wood under vacuum or vacuum pressure.

[0013] A decorative sheet has been invented, which comprises a flexible substrate such as felt, to which a thin natural wood board is bonded, the surface of which is coated with a flexible transparent resin that can bend 180°. The thickness of the thin board is 0.3 to 0.6 mm, the bonding is via a urea-containing adhesive, and the flexible transparent resin is a mixture of a solvent-containing acrylic resin and a solvent-containing isocyanate compound in a solvent ratio of 5:1 to 1:3. Some solvents and chemicals used in flexible transparent resins are harmful to the human body and must be handled with care.

[0014] Chopstick cases for eating utensils made from thin wooden boards are made of thin wooden boards made from cypress or other softwood materials, with a thickness of 0.1 to 1 mm. One or both sides of the board are coated with a polyolefin film to create a natural wood-like surface. The adhesive used in the film is an ethylene-vinyl acetate copolymer or polysaccharide. The chopstick cases for eating utensils are foldable bags made from a single rectangular flat board, and are chopstick tip bag-like covers, with the two vertical and bottom edges of the folded rectangular bag-like container glued together with adhesive. In other words, a chopstick case has been devised in which a rectangular thin board is folded in half into a long, narrow shape and the vertical and bottom edges are glued together. This device is used by folding a thin plate in half, as shown in the figure, i.e. the plate is split but remains in shape thanks to the adhesive coating of the film.

[0015] The present invention has been made to solve the problems that have existed in the past: in materials using thin natural wood boards, there is a demand for flexible thin boards that have a beautiful grain surface, are resistant to scratches, and do not crack when bent. [Means for solving the problem]

[0016] The bent flexible thin natural wood board is produced by using a super-finishing planer, and has a thickness of 0.05 mm or more and 0.3 mm or less. Thermoplastic resin films are adhered to both sides of the natural wood board, and further, cloth is adhered to one side of the thermoplastic resin film with a double-sided tape adhesive. Usually, thin plates are produced using a slicer or rotary slicer. In the present invention, thin plates that have been shaved using a super-finish planer were used. The thickness of the thin plate is preferably 0.05 mm or more and 0.3 mm or less. If it is thicker than 0.3 mm, it may break when bent 180 degrees, and if it is thicker than 0.05 mm, it is difficult to make it with a super-finish planer. As the thermoplastic resin film, a polypropylene film, a polyethylene film, or the like is used. The double-sided tape adhesive used was Bond WF004N, manufactured by Konishi Co., Ltd., with a nonwoven fabric backing, acrylic resin adhesive, and a thickness of 0.14 mm. Normal adhesives may also be used. The fabric used is No. 11 canvas, which is thinner than other canvases and can be sewn easily with a sewing machine.

[0017] The bent flexible thin natural wood board is made from cedar or cypress, and is made by using a heat roll to attach a polypropylene film, which can be used for foil stamping of thermoplastic resin film and screen printing, to both sides of the natural wood board with a polyolefin adhesive, and then attaching canvas to one side of the natural wood board with double-sided tape adhesive to the polypropylene film attached to both sides.When tested using a cylindrical mandrel bending tester with a minimum mandrel diameter of 2 mm, the bent flexible thin natural wood board does not crack when bent parallel to the direction of the wood grain or perpendicular to the direction of the wood grain.

[0018] The wood species used were cedar and cypress. The polypropylene film was given a matte finish so that it could be used for foil stamping and screen printing. The bending strength of natural wood flexible thin plates was tested using JIS K5600-5-1 bending resistance test (cylindrical mandrel) (tested at Wakayama Prefectural Industrial Technology Center). The results are shown in Tables 1 and 2. Table 1. Cylindrical mandrel bending test results for 0.1 mm thick natural wood thin board samples (Mandrel diameter 2mm) TIFF2026043598000002.tif31124 As can be seen from the results in Table 1, in the case of bent flexible thin boards of cypress wood, samples of natural wood thin boards with a thickness of 0.1 mm did not crack in either the cross grain or the straight grain even when bent 180° in directions parallel and perpendicular to the fiber direction using a mandrel with a diameter of 2 mm. In addition, in the case of bent flexible thin boards of cedar wood, samples of 0.1 mm thick boards did not crack in the straight grain even when bent 180° in directions parallel and perpendicular to the fiber direction using a mandrel with a diameter of 2 mm.

[0019] Next, the thickness of the natural wood thin board was changed to 0.3 mm, 0.4 mm, and 0.5 mm, and a cylindrical mandrel bending test (mandrel diameter 2 mm) was performed. The results are shown in Table 2. Table 2. Thickness of natural wood thin board samples: 0.3mm, 0.4mm, 0.5mm Cylindrical mandrel bending test results (Mandrel diameter 2mm) TIFF2026043598000003.tif73149 As shown in Table 2, in the case of flexible thin boards of cedar, a 0.3 mm thick sample of a plain grain natural wood thin board did not crack even when bent 180° in a direction perpendicular to the grain direction using a mandrel diameter of 2 mm. In addition, when a 0.4 mm thick specimen of flat-grain natural wood thin board was bent 180 degrees perpendicular to the grain direction using a 2 mm diameter mandrel, the thin board cracked. However, when a 0.4 mm thick specimen of flat-grain natural wood thin board was bent 180 degrees parallel to the grain direction using a 2 mm diameter mandrel, the thin board did not crack. This shows that when bent 180 degrees in a direction perpendicular to the fiber direction, it is prone to cracking, but when bent parallel to the fiber direction, it is less likely to crack than when bent perpendicular to the fiber direction. In the case of bending flexible thin boards of cedar, when a 0.5 mm thick specimen of a natural wood thin board with a flat grain was bent 180° in directions perpendicular and parallel to the grain direction using a mandrel with a diameter of 2 mm, the thin board cracked in both directions.

[0020] From the above results, it can be seen that bending perpendicular to the fiber direction makes it easier to crack than bending parallel to it. When the thickness of a thin plate is 0.3 mm or less, the plate will not crack even when bent 180 degrees perpendicular to and parallel to the fiber direction. However, when the thickness of a thin plate is 0.5 mm or more, the plate will crack when bent 180 degrees perpendicular to and parallel to the fiber direction. It can be seen that when the thickness of a thin plate is 0.4 mm, the plate will crack when bent perpendicular to the fiber direction, but not when bent parallel to the fiber direction. It is thought that applying polypropylene film to both sides of the natural wood thin boards prevents the boards from cracking, but it has now been confirmed for the first time that cracking due to bending can be prevented by reducing the thickness of the boards to 0.3 mm or less.

[0021] The bag is made using the bent flexible thin sheet of natural wood, with the side with the fabric facing out, and after sewing both sides, the bag is immersed in hot water at 70°C to 100°C for 1 minute, and then turned over to expose the inside, so that the side with the fabric facing inwards, in order to hide the seams. Since the non-crystalline hemicellulose and lignin that are components of wood are thermoplastic, it is thought that the moisture acts as a plasticizer to plasticize the wood.

[0022] The natural wood bent flexible thin plate is used to produce a pen case, a mobile phone case, a coin purse, a business card case, a long wallet, and a bifold wallet. The pen case has a zipper at the top for opening and closing, and the bent flexible thin board of natural wood is bent 180 degrees perpendicular to the direction of the board's fibers at the bottom, with the canvas-covered side facing inwards, so that the beauty of the wood grain is visible on the outside. The surface is also printed with trademarks and other information using polypropylene film that can be foil stamped and screen printed. The sides are sewn with reinforcing fabric (bamboo fringe). [Effects of the Invention]

[0023] The thickness of the natural wood thin board is 0.05 mm or more and 0.3 mm or less. A thermoplastic resin film is bonded to both sides of the natural wood thin board, and a cloth is further attached to one side of the thermoplastic resin film with double-sided tape. This bent flexible natural wood thin board is resistant to scratches. When this bent flexible natural wood thin board is tested using a cylindrical mandrel bending tester with a minimum mandrel diameter of 2 mm, it does not crack even when bent parallel to or perpendicular to the grain direction of the wood. In other words, the thin board does not crack even when bent 180 degrees. This material can be used to make pencil cases and other items with beautiful wood grain and a scratch-resistant surface. [Brief explanation of the drawings]

[0024] [Figure 1] Schematic cross-section of natural wood flexible thin board [Figure 2] A schematic perspective view of a pen case made from thin, bent natural wood panels DETAILED DESCRIPTION OF THE INVENTION

[0025] Examples of the present invention are shown below, but the present invention is not limited to these examples. [Example]

[0026] FIG. 1 shows a schematic cross-sectional view of a flexible bent natural wood thin board (1). In the bent flexible thin natural wood board (1), the natural wood board (4) is produced using a super-finishing planer, and the thickness of the natural wood board (4) is 0.05 mm or more and 0.3 mm or less. Thermoplastic resin films (2) are adhered to both sides of the natural wood board (4), and further, cloth (6) is adhered to one side of the thermoplastic resin film (2) with a double-sided tape adhesive (5) to form the bent flexible thin natural wood board (1). Usually, the thin plate (4) is produced by a slicer or a rotary slicer. In the present invention, the thin plate (4) was used, which was cut by a super-finish planer. The thickness of the natural wood thin board (4) is preferably 0.05 mm or more and 0.3 mm or less. If it is more than 0.3 mm, it may break when bent 180 degrees, and if it is less than 0.05 mm, it is difficult to make it with a super-finish planer. As the thermoplastic resin film (2), a polypropylene film, a polyethylene film, or the like is used. The double-sided tape (5) used was Bond WF004N, manufactured by Konishi Co., Ltd., with a nonwoven fabric backing, acrylic resin adhesive, and a thickness of 0.14 mm. A general adhesive may also be used. The fabric (6) is made of No. 11 canvas, which is relatively thin among canvases and can be sewn easily with a sewing machine. [Example]

[0027] In the bent flexible thin natural wood board (1), the tree species is cedar or cypress, and a polypropylene film that can be used for foil stamping of a thermoplastic resin film (2) and screen printing is attached to both sides of the thin natural wood board (4) using a heat roll with a polyolefin adhesive (3), and further, canvas (6) is attached to one side of the thin natural wood board (4) with a double-sided tape adhesive (5) to form the bent flexible thin natural wood board (1).When tested using a cylindrical mandrel bending tester with a minimum mandrel diameter of 2 mm, the thin natural wood board (4) does not crack even when bent parallel to the grain direction of the wood or perpendicular to the grain direction of the wood. The wood species used were cedar and cypress. The polypropylene film was given a matte finish so that it could be foil stamped and screen printed. The bending test of the natural wood flexible thin board was carried out using a JISK5600-5-1 AQC bending resistance test (cylindrical mandrel) (tested at Wakayama Prefectural Industrial Technology Center). [Example]

[0028] The bag is made using a bent flexible thin sheet of natural wood (1) with the surface with the cloth (6) attached facing out, and after sewing both sides, the bag is immersed in hot water at 70°C to 100°C for 1 minute, turned over to expose the inside, and the surface with the cloth (6) attached facing inward, in order to hide the seams. Since the non-crystalline hemicellulose and lignin that are components of wood are thermoplastic, it is thought that the moisture acts as a plasticizer to plasticize the wood. [Example]

[0029] FIG. 2 shows a schematic perspective view of a pen case (7) made using a thin, bent, flexible natural wood plate (1). The pen case (7) has a zipper (10) at the top that can be opened and closed, and the bent flexible thin natural wood board (1) is bent 180 degrees perpendicular to the fiber direction of the board at the bottom, with the canvas (6) attached side facing inward, so that the beauty of the wood grain (8) can be seen on the outside. The surface is printed with a polypropylene film (2) that can be foil stamped and screen printed. The sides are sewn with a reinforcing fabric (bamboo edge) (11). The following items are made using natural wood bent flexible thin boards (1): a pen case (7), a mobile phone case, a coin purse, a business card case, a long wallet, and a bifold wallet. In products made from natural wood bent flexible thin boards (1), it is best to use the wood grain in the straight grain direction, and the wood grain in the cross grain direction. For example, in a bifold wallet, the board is folded in half parallel to the grain direction, so the board will not crack or leave scratches. On the other hand, if the board is used in the cross grain direction, the board will be folded in half perpendicular to the grain direction, and at the bottom, the board will be folded in half parallel to the grain direction and then folded vertically, which may cause cracks and scratches. [Example]

[0030] In the case of a bent flexible thin plate (1) of cypress wood, a 0.1 mm thick sample of natural wood thin plate (4) was bent 180° parallel and perpendicular to the grain direction using a mandrel with a diameter of 2 mm, and the thin plate did not crack in either the cross grain or the straight grain. In addition, in the case of a bent flexible thin board (1) made of cedar wood, a 0.1 mm thick sample of natural wood thin board (4) was bent 180° in directions parallel and perpendicular to the fiber direction using a mandrel with a diameter of 2 mm, but the thin board (4) and the straight grain did not crack. [Example]

[0031] In the flexible cedar thin board (1), a 0.3 mm thick specimen of the flat grain thin board (4) did not crack even when bent 180° perpendicular to the grain direction using a mandrel with a diameter of 2 mm. When a 0.4 mm thick specimen of cedar plank (4) was bent 180° in a direction parallel to the grain direction using a mandrel with a diameter of 2 mm, the specimen did not crack. (Comparative Example 1)

[0032] In the bending flexible thin board (1) of cedar wood, when a specimen of the flat grain thin board (4) with a thickness of 0.4 mm was bent 180° in a direction perpendicular to the grain direction using a mandrel with a diameter of 2 mm, the thin board (4) cracked. From the results of Example 6 and the above, it can be seen that when bent 180° in a direction perpendicular to the fiber direction, the film is prone to cracking, but when bent parallel to the fiber direction, it is less likely to crack than when bent perpendicular to the fiber direction. In the bending flexible thin board (1) of cedar wood, when a 0.5 mm thick specimen of the flat grain thin board (4) was bent 180° in directions perpendicular and parallel to the grain direction using a mandrel with a diameter of 2 mm, the thin board (4) cracked in both directions. From Example 6 and the above results, when the thickness of the thin plate (4) is 0.3 mm or less, the thin plate (4) does not crack even when bent 180 degrees in directions perpendicular and parallel to the fiber direction. However, when the thickness of the thin plate (4) is 0.5 mm or more, the thin plate (4) cracks when bent 180 degrees in directions perpendicular and parallel to the fiber direction. It can be seen that when the thickness of the thin plate (4) is 0.4 mm, it cracks when bent perpendicular to the fiber direction, but does not crack when bent parallel to the fiber direction. [Industrial Applicability]

[0033] The thickness of the bent flexible natural wood thin board is 0.05 mm or more and 0.3 mm or less. A thermoplastic resin film is bonded to both sides of the natural wood thin board, and a cloth is further attached to one side of the thermoplastic resin film with double-sided tape. This bent flexible natural wood thin board has a beautiful wood grain surface and is resistant to scratches. When tested using a cylindrical mandrel bending tester with a minimum mandrel diameter of 2 mm, the bent flexible natural wood thin board does not crack even when bent parallel to or perpendicular to the grain direction of the wood. In other words, the thin board does not crack even when bent 180°. This material can be used to make beautiful wood-grained pencil cases, cell phone cases, coin purses, bags, business card holders, long wallets, bifold wallets, and other items. [Explanation of symbols]

[0034] 1. Flexible natural wood thin board 2 Film 3. Adhesive 4 Natural wood veneers 5 double-sided tape adhesive 6 cloth 7. Pencil Case 8 Natural wood grain 9 Printed part 10 zippers 11 Edge reinforcement fabric (bamboo edge)

Claims

1. The bent flexible thin natural wood board is manufactured by using a super-finishing planer, has a thickness of 0.05 mm or more and 0.3 mm or less, has thermoplastic resin films adhered to both sides of the natural wood board, and further has a cloth adhered to one side of the thermoplastic resin film with a double-sided tape adhesive.

2. The bent flexible thin natural wood board according to claim 1, characterized in that the tree species is cedar or cypress, and a polypropylene film that can be used for foil stamping and screen printing of thermoplastic resin film is attached to both sides of the natural wood board using a heat roll with a polyolefin adhesive, and further, a canvas is attached to one side of the natural wood board with the polypropylene film attached to both sides with a double-sided tape adhesive, when tested using a cylindrical mandrel bending tester with a minimum mandrel diameter of 2 mm, the natural wood board does not crack even when bent parallel to or perpendicular to the direction of the wood grain.

3. In the bag made using the bent flexible thin plate of natural wood described in claim 2, the side with the cloth attached is turned to the outside, and after sewing both sides, the bag is immersed in hot water at 70 to 100°C for 1 minute to hide the seams, and then turned over to turn the inside out, so that the side with the cloth attached is turned to the inside.

4. A pen case, a mobile phone case, a coin purse, a business card case, a long wallet, or a bifold wallet made using the natural wood bent flexible thin plate according to claim 2.

Images