JPH0623894A - Wooden molded material and production thereof - Google Patents

Abstract

PURPOSE:To obtain a lightweight and tough molded material having surface fastness, easily coated with paint, reducing the penetration of paint, obtaining a film having good gloss, provided with a painting layer good in dirability and dimensional stability and inexpensively produced. CONSTITUTION:A wooden molded material is constituted of a core part 1 formed by integrally molding a long wooden fiber and a thermosetting resin binder contained in an amount of 5-30% by wt. of the fiber and surface layers 2 formed by integrally molding a thermosetting resin binder containing a short wooden fiber in an amount of 30-400wt.%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an inner wall of a house, a partition,
The present invention relates to a wood molding material that can be used as a constituent material of doors, shelves, furniture / furniture, musical instruments, electric / audio equipment, toys, and the like, and a manufacturing method thereof.

[0002]

2. Description of the Related Art Wood obtained by defibrating wood chips by mixing it with a synthetic resin binder such as phenol resin or amino resin to form a sheet and then hot pressing it. Fiber materials are already known. Such wood fiber materials are classified, for example, as soft fiber board, semi-hard fiber board, and hard fiber board from the specific gravity thereof, but the difference in such specific gravity is mainly due to the papermaking density of wood fibers. It is due to the pressure difference of hot press molding,
Each of the wood fiber materials has a uniform cross-sectional structure, its surface is more or less porous, and its hygroscopicity, water absorption and oil absorption are extremely high.

[0003]

Such a conventional wood fiber material has a low surface hardness and is easily damaged by a slight scratch or impact. In addition, when coating the surface, not only is the paint infiltrated into the tissue in large quantities and wasted, but also the coated surface does not appear glossy, and deformation and distortion of the coated object occur due to contraction of the impregnated paint components, There were also problems with dimensional stability and durability such as cracks on the coated surface.

In order to solve such a problem, conventionally, a method of laminating a resin layer on the surface of the wood fiber material has been proposed. There are two methods for this, and one of them is a method in which a backing material such as cured paper impregnated with a phenol resin is post-applied to the surface of the wood fiber material that has been thermocompression molded. The molded product obtained by this method does not soak into the paint during coating, and the state of the coated surface and impact resistance are good. However, the number of man-hours for post-adhesion is required, and the cost is high. Another method is a method of forming a wood fiber material by laminating a mixed paper product of wood fibers and a binder with a prepreg sheet such as a phenol resin-impregnated uncured sheet in advance and thermoforming the laminate. The molded product obtained by this method does not require man-hours for post-adhesion, but the gas generated during thermocompression molding is retained inside by being blocked by the non-breathable prepreg sheet, and molding is performed when hot pressure is released. Irregular unevenness due to bubbles is generated on the surface of the object. Such surface irregularities cannot be hidden by painting.

Therefore, an object of the present invention is to solve the above-mentioned problems, to obtain a glossy coated surface without sacrificing the coating material during coating, the surface being smooth and hard, and the dimensional stability and durability of the coated material. (EN) Provided is a wood molding material which is excellent in manufacturing cost and does not require extra man-hours in manufacturing the wood molding material, and a manufacturing method thereof.

[0006]

This problem is solved by the problem that a long fiber wood fiber is integrally molded with a thermosetting resin binder in an amount of 5 to 30% of the weight of the fiber core, and a short fiber wood fiber. Can be solved by providing a wood molding material comprising a surface layer portion integrally formed with 30 to 400% of its weight by a thermosetting resin binder. In the above, the fiber length of the wood fiber in the core is preferably 5 to 50 mm. In the above, the fiber length of the wood fiber of the surface layer is 2 to 5
It is preferably mm. The above wood molding material comprises a core paper product obtained by paper-forming a long-fiber wood fiber with an uncured thermosetting resin binder of 5 to 30% of its weight, and a short-fiber wood fiber of 30% by weight. It can be manufactured by laminating an uncured thermosetting resin binder of up to 400% and a surface layer part paper product obtained by paper-making to form a laminated paper product, and then thermocompressing the laminated paper product. In the above manufacturing method, the fiber length is 5 to 5 as the wood fiber of the long fiber.
It is preferable to use one that is 50 mm. In the above production method, the fiber length of the short wood fibers is 2 to
It is preferable to use one that is 5 mm.

Next, the wood molding material of the present invention and its manufacturing method will be described with reference to the drawings. FIG. 1 shows an embodiment of the wood molding material of the present invention molded in the form of a panel.
In FIG. 1, 1 is a core part and 2 is a surface layer part. This panel includes a core portion 1 formed in a sheet shape and a surface layer portion 2 formed in a sheet shape on both surfaces thereof.

The core portion 1 is formed by integrally molding long wood fibers with a thermosetting resin binder of 5 to 30% of the weight thereof. The wood fiber that constitutes the core 1 is obtained by chipping wood such as spruce, cypress, lauan, beech, and hippopotamus, and defibrating it through a steaming process, which has a long fiber length and toughness. It is expensive. The wood fibers of long fibers are bulky and rich in toughness.
The wood molding material obtained by using this is light and has excellent flexibility. The wood fiber used for molding the core 1 is
In particular, the fiber length is preferably 5 to 50 mm.
When the fiber length is 5 mm or less, it becomes difficult to mold the core portion 1 to be lightweight and flexible, and when the fiber length is 50 mm or more, the fibers are entangled with each other during the production, and it is difficult to obtain a homogeneous paper product.

The thermosetting resin binder in the core portion 1 is used as an adhesive for the wood fibers. As the thermosetting resin binder, any of those conventionally used as a binder for wood fiber molding materials can be used. Examples thereof include a composition containing a phenol resin, an epoxy resin, a melamine resin, a urea resin, a urethane resin, or a modified product or a mixture thereof as a main component. However, in order to increase the flexibility of the core portion 1, it is preferable to use a polyurethane-modified thermosetting resin composition, for example, a 2/1 composition of urea resin / MDI polyurethane resin. This resin composition may contain a curing agent or a curing accelerator.

In the integral molding of the core part 1, these uncured thermosetting resin compositions are mixed so as to uniformly adhere to the surface layer of the wood fiber. The resin composition used at this time may be in the form of any of an organic solvent solution, an aqueous emulsion, an aqueous suspension, and a powder, in short, when uniformly attached to the surface of the wood fiber and heated. The contacts between the wood fibers may be bonded by curing. The mixing ratio of the thermosetting resin binder used in the core portion 1 is in the range of 5 to 30% by weight of the wood fiber. If it is 5% or less, sufficient adhesion cannot be obtained when integrally molding wood fibers, and if it is 30% or more, not only does the wood fiber of the core 1 adhere excessively densely and the volume is reduced and weight reduction cannot be achieved. However, the wood fiber and the resin are excessive, and the extra cost increases.

The surface layer portion 2 is formed by integrally molding short wood fibers with 30 to 400% by weight of the thermosetting resin binder. The wood fiber that constitutes the surface layer portion 2 is obtained by chipping wood such as spruce, cypress, lauan, beech, and hippopotamus, and defibrating it through a steaming process, which has a short fiber length. used. Since the wood fiber of the short fiber is dense in its papermaking product, the use of it makes the surface of the obtained wood-based molding material hard and smooth, and retains hygroscopicity, water absorption, and oil absorption while maintaining breathability. It can be reduced. The wood fiber used for forming the surface layer 2 preferably has a fiber length of 2 to 5 mm. When the fiber length is 2 mm or less, the entanglement of the fibers in the surface layer part 2 is insufficient, the surface of the obtained wood-based molding material loses toughness, and when the fiber length is 5 mm or more, the denseness of the surface layer part 2 is lost. However, the effect of providing the surface layer portion 2 is reduced.

The thermosetting resin binder in the surface layer portion 2 is used as an adhesive agent between the wood fibers and as a matrix element constituting the surface layer portion 2. As the thermosetting resin binder, any of those conventionally used as a binder for wood fiber molding materials can be used. Examples thereof include a composition containing a phenol resin, an epoxy resin, a melamine resin, a urea resin, a urethane resin, or a modified product or a mixture thereof as a main component. However, in order to enhance the hardness and water repellency of the surface layer portion 2, it is preferable to use a phenol novolac resin, a melamine resin, an epoxy resin or a modified resin composition thereof. This resin composition may contain a curing agent or a curing accelerator.

When the surface layer portion 2 is integrally molded, these uncured thermosetting resin compositions are uniformly mixed with the wood fibers. The resin composition used at this time may be in the form of any of an organic solvent solution, an aqueous emulsion, an aqueous suspension, and a powder, but in order to enhance the smoothness of the surface and reduce the water absorption and oil absorption properties. It is preferable to use an uncured powder resin composition, for example, a powder phenol novolac resin composition (including a curing agent). The mixing ratio of the thermosetting resin binder used in the surface layer portion 2 is 30 to 400 of the weight of the wood fiber.
It is within the range of%. When it is 30% or less, sufficient hardness and smoothness cannot be obtained on the surface, and the effect of reducing hygroscopicity, water absorption and oil absorption becomes small. When it is 400% or more, the wood texture of the surface layer is lost, and the use of an excessive amount of resin causes an additional cost.

The wood molding material of the present invention comprises a core portion 1 and a surface layer portion 2.
It can also be manufactured by individually molding and integrally joining each member, but core part papermaking obtained by papermaking of long fiber wood fiber with uncured thermosetting resin binder And a surface layer part obtained by paper-making an uncured thermosetting resin binder and wood fibers of short fibers are laminated before being heat-cured to form a laminated paper product, and then this laminated paper product is subjected to thermocompression molding. The manufacturing method of the present invention is a preferable manufacturing method because the wood molding material of the present invention can be obtained by one-time thermocompression molding, and the number of steps can be reduced.

In the manufacturing method of the present invention, for example, on a base placed in a hot press (for example, a hot press), first, the wood fiber forming either the core portion 1 or the surface layer portion 2 and the uncured thermosetting material are used. The mixture of resin binders is formed into a desired thickness by papermaking (accumulation / shaping) to form a papermaking product. On this, the mixture that forms the other is formed into a desired thickness to form a laminated paper product. At this time, any of wet, semi-wet, and dry papermaking methods may be adopted. A core 1 as shown in FIG.
In the case of producing a wood molding material having the surface layer portions 2 on both sides, the above-described papermaking operation is performed in the order of surface layer papermaking, core papermaking, and surface layer papermaking to form a three-layer laminated papermaking product. Next, while pressing this laminated paper product from above with a constant pressure with a pressure plate, it is heated to the curing temperature of the thermosetting resin in the paper product,
Hold for a predetermined time to perform thermocompression molding. As such a hot-pressing device, both batch-type and continuous-type can be used which are usually used in this field. In the wood molding material manufactured by the manufacturing method of the present invention as described above, since the respective fibers are entangled at the interface between the core portion 1 and the surface layer portion 2 and both resins are adhered in an overlapping manner, bending stress and Delamination does not occur due to shear stress.

The wood molding material of the present invention includes not only those having surface layers 2 on both surfaces of a core 1 as shown in FIG. 1, but also those having surface layers 2 on only one surface of the core 1. Good. The wood molding material of the present invention is not limited to a flat plate shape, but a curved shape, a columnar shape whose peripheral surface is covered with the surface layer 2, or an embossed or engraved surface on the surface of the surface 2. It may be provided with an uneven pattern.
Such a concavo-convex pattern can be imparted by, for example, engraving the surface of the die for hot-pressing the laminated paper product.

The wood molding material of the present invention has a flame retardant, a pigment, an insect repellent, an antiseptic and fungicide, a water repellent, a sound absorbing material, foam beads, a filler, and a reinforcing material on the core 1, the surface layer 2 or both. And the like. These additives can be blended with the wood-forming material of the present invention by adding them to the composition before papermaking of the core and the surface layer, for example.

[0018]

Next, one embodiment of the present invention will be described in more detail. In this embodiment, as shown in FIG. 1, a panel-shaped wood molding material is used. In FIG. 1, 1 is a core,
2 is a surface layer part. This panel includes a core portion 1 formed in a sheet shape and a surface layer portion 2 formed in a sheet shape on both surfaces thereof.
It consists of This panel has a specific gravity of 0.55 to 0.
60 and the thickness is 19 mm.

The type of material forming the core 1 of the panel,
The weight ratio of the wood fibers is shown below when the wood fiber is 100. Fiber length 5 to 50 mm, fiber diameter 0.1 to 1.0 mm
Wood fiber, 100 parts by weight. 2/1 of urea resin / crude MDI polyurethane resin as thermosetting resin binder
Composition, 20 parts by weight. And paraffin water repellent, 1.0
Parts by weight. The thickness of this core 1 is 15 mm.

Next, the kind of material forming the surface layer 2 and
The weight ratio of the wood fibers is shown below when the wood fiber is 100. Fiber length 2-5 mm, fiber diameter 0.1-0.5 mm wood fiber, 100 parts by weight. As a thermosetting resin binder, phenol novolac resin (including a hexamethylenetetramine curing agent), 300 parts by weight. The surface layer portions 2 each have a thickness of 2 mm.

This panel was manufactured as follows. On a smooth hot plate of a hot press machine, 100 parts by weight of wood fiber having a fiber length of 2 to 5 mm and a fiber diameter of 0.1 to 0.5 mm, and an uncured powdered phenol novolac resin (including a hexamethylenetetramine curing agent) A surface layer composition (composition A) consisting of 300 parts by weight was uniformly sprayed at a rate of 1,100 g per 1 m ^{2 to} produce a paper. Next, on this paper product, a fiber length of 5 to 50 mm, a fiber diameter of 0.1 to 1.0 mm, 100 parts by weight of wood fiber, and an uncured urea resin / crude MDI polyurethane resin 2/1 composition 20 parts by weight. And 1.0 part by weight of a paraffinic water repellent were uniformly sprayed at a rate of 8,250 g per 1 m ^{2 to} produce a paper. 1 m ² per Composition A over more that paper product,
It was uniformly sprayed at a rate of 100 g to make a paper. In this way, a laminated paper product comprising three layers of the surface layer paper product / the core paper product / the surface layer paper product was formed on the hot plate and
It was pressed at 0 kg / cm ² and heated to 150 ° C. for 13 minutes. After heating, the hot pressure was released and the product was held horizontally and cooled.
The obtained panel had a smooth and hard surface, and the interface between the surface layer and the core was closely adhered.

A coating test was conducted on this panel. The surface of the panel was ground with a # 60 to # 80 sander, and a black polyester paint was applied on this. The coating was carried out smoothly, there was little penetration of the paint, and a coating film having specular gloss was obtained.

Each of the painted panels was at 35 ° C.
When an environmental test was conducted by leaving it at 95% relative humidity for 20 days and at 35 ° C. and 20% relative humidity for 20 days, no abnormalities in appearance, dimensions, and strength were observed. From this example, it is clear that the wood molding material of the present invention produced by the production method of the present invention has excellent surface characteristics, dimensional stability and durability.

[0024]

Industrial Applicability The wood molding material of the present invention comprises a core part formed by integrally molding a long wood fiber with a thermosetting resin binder of 5 to 30% of its weight, and a short wood fiber. Since it is composed of a thermosetting resin binder of 30 to 400% of the weight and a surface layer part integrally formed, it is lightweight and tough, the surface is robust, and it can be applied smoothly when painting. As a result, there is an effect that a coating film with less penetration of a paint and a high gloss can be obtained, the durability and dimensional stability of the coated product are good, and the manufacturing cost is low.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a wood molding material of the present invention.

[Explanation of symbols]

 1 ... Core part, 2 ... Surface layer part.

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Claims (6)

[Claims] 1. The long wood fiber is used in an amount of 5 to 30% by weight.
% Of a thermosetting resin binder and a core portion integrally formed with the thermosetting resin binder, and a surface layer portion of a short wood fiber integrally formed with 30 to 400% by weight of the thermosetting resin binder. Molded wood material characterized by. 2. The wood molding material according to claim 1, wherein the wood fiber of the core portion has a fiber length of 5 to 50 mm. 3. The wood molding material according to claim 1, wherein the wood fiber of the surface layer has a fiber length of 2 to 5 mm. 4. A core papermaking product obtained by making a wood fiber of long fiber in an amount of 5 to 30% by weight of the uncured thermosetting resin binder in the production of the wood molding material according to claim 1. 30% to 400% of the weight of short fiber wood fiber
1. A method for producing a wood molding material, which comprises laminating an uncured thermosetting resin binder of 1) and a surface layer part paper product obtained by paper-making into a laminated paper product, and then thermocompressing the laminated paper product. 5. The method for producing a wood molding material according to claim 4, wherein the long wood fibers having a fiber length of 5 to 50 mm are used. 6. The method for producing a wood molding material according to claim 4, wherein the short wood fibers have a fiber length of 2 to 5 mm.