JPH0419936B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the provision of a wood-based composite board, particularly a synthetic plywood whose expansion/contraction strain and flexure have been corrected.

However, in the case of conventional plywood made by laminating and gluing veneers, due to the material characteristics of the veneer itself, it is prone to warping, distortion, or cracking. Even in plywood constructed to correct this, expansion and contraction distortions occur due to changes in the water content, often leading to warping of the plywood itself and peeling of the laminated surfaces of the plywood.

Therefore, in order to obtain better quality plywood, the selection and combination of the veneers themselves are considered to be important, and the material cost, which accounts for the molding cost, is particularly high.

The synthetic plywood according to the present invention has been specially devised in view of the disadvantages of the conventional plywood, and has the following features:
In order to remove the unique characteristics of wood as a material, it is crushed to form a pure wood powder state, which removes the directional properties of wood such as expansion, contraction and distortion, as well as the heat insulation, which is the advantage of wood. It is a composite board that is made of resin while retaining sound insulation and moisture absorption functions, has particularly good wear resistance, and does not suffer from molding distortion or distortion over time after molding.
Furthermore, the variations in residual stress in the extrusion direction and extrusion lateral direction, which are induced in the extrusion operation of the composite board, are mutually compensated and absorbed by the overlapping of the composite boards. This is to ensure that there is no room for warpage, distortion, etc. to occur.

In the molding of such a unique composite board, in order to improve its compatibility with wood powder, which is a problem, and to suppress the generation of wood acid gas and water vapor during molding, we have taken measures to prevent inconveniences during molding. In order to effectively prevent the disadvantages brought about in terms of the quality of the molded product, and in order to achieve effective results in such characteristics, the outline of its composition is particularly explained. A suitable cellulose-based material is dried so that the moisture content of the material is within 15o/wt to induce collapse of its fiber structure, and a urea-based resin liquid is applied to the processed material. impregnation, then drying and crushing the processed material in a temperature range of 100°C to 250°C to form a neutralized finely hardened aggregate with a pH of 6 to 7; and chlorination of the neutralized finely hardened aggregate. It consists of a step of molding a synthetic board material mixed with a thermosetting resin material such as vinyl and extrusion molded, and a step of laminating and bonding this synthetic board material so that the extrusion direction of the board material is sequentially orthogonal to each other. It is placed in the combination of In addition, in the present invention, the following specific embodiments accompanying the gist of the configuration and embodiments of considerable other bypass means accompanying these embodiments are planned. .

An example of a typical molding example of the wood-like synthetic plywood according to the present invention will be described below with reference to the attached drawings.
The following plywood materials are mixed with a at 20 to 60o/wt for sheet-like products and 5 to 40o/wt for film-like products, whether non-foamed or foamed. This is what was said.

In extrusion molding using such aggregate 1a, the material is usually extruded into a cylindrical shape and then cut open to form a sheet or film. The extruded dough material is once divided by a mounting rod interposed to support the mold, and then extruded in close contact with each other into a tube shape. Therefore, in the composite board 1, as shown in FIG. 2, the mixed aggregate 1a has a sparse m density n part, and the mixing density of the mixed aggregate 1a and the undulation during extrusion. As a result of this phenomenon, the composite board 1 began to warp and become distorted. The connecting rod between the outer shape and the inner mold in this die itself acts as an extrusion resistance part during extrusion, and together with the extrusion resistance of the aggregate 1a, the resin fabric on the peripheral surface of this rod is compressed. In other words, it is extruded in a dense manner.

Aggregate 1a and resin fabric 1 in such board 1
The warpage and distortion that occur in board 1 due to the coarseness m and density n of b are not as severe as in normal veneers, and are generally considered to be almost negligible. In particular, when dimensional accuracy is required, these composite plates 1 are made with different directions of warpage and distortion due to the above-mentioned density, so that the extrusion directions of the plates 1 are sequentially orthogonal to each other. Board 1 in the direction of
By laminating 1 to 1 and bonding them together, the inherent warpage and distortion of each board 1 to 1 is mutually corrected, and in the state of the laminated plywood a, it can be fixed in any direction. It is constructed so that no residual stress remains even when the

As a result, both the molding distortion due to the sparseness and density of the structure itself left in the composite board 1 and the distortion over time after molding are reliably corrected, and the distortion due to temperature change, humidity change, and time-dependent factors are reliably corrected. Warping and distortion of the plywood a due to this are reliably prevented.

The plywood a according to the present invention has such characteristics, and is particularly intended to be used as a composite board 1 formed by mixing and molding a special molded aggregate described below. Below, to explain the molding method of this special composite board 1, first, the materials to be prepared are thermoplastic resin materials such as vinyl chloride, ABS resin, and polystyrene, mixed aggregate based on wood flour, Calcium carbonate powder hardening agent, stabilizer, coloring agent, etc. are added as necessary.

The aggregate used was then neutralized using the following procedure. That is, crushed chip material,
A cellulosic material such as pulp or rice husk is prepared and pre-processed by drying, especially heat drying, so that the moisture content of the material is within 15o/wt. As the moisture content in the material decreases to within 15o/wt, the drying process rapidly induces destruction of the constituent fiber structure of the material, resulting in coarse bundles of cellulose or crushed chips in the form of lumps. The composition of the cellulose in wood, pulp material, and rice husk is certainly destroyed, and the cellulose is in a disorganized state.

By applying an emulsion-type urea resin adhesive to the material that has dried and whose structure has disintegrated, and leaving it for 20 to 30 minutes,
This urea-based resin adhesive liquid is sufficiently impregnated into the material, and usually has a pH value of about 5.

In addition, ammonia chloride or hydrochloric acid is separately added to this resin adhesive liquid as a hardening agent, and the material
Attempts were made to further adjust the pH value toward neutrality as necessary.

In this way, the material impregnated with the urea-based resin liquid and cured is subjected to heat drying, crushing, hardening, and pulverization in the range of 100°C to 250°C in the next step. and the moisture content is 3~5o/wt.
It is made into a fine hardened powder with a particle size of about 100 to 150 mesh, and is made to be as close to 0o/wt as possible.

During such heat drying and crushing, the material itself
The pH value is within the range of 6 to 7, and it is generally adjusted to be neutral.

The neutralization treatment of the acidic material at such a starting point is
This is largely due to the action of the urea-based resin adhesive that is interposed during the process, and in simple heating and drying treatments of cellulose materials that do not include the addition of urea-based resin adhesives. Compared to the pH5 of the starting material, the final point material, which is made into a dry fine powder,
The PH value is 2 to 3, which means that the PH value tends to be acidic. On the other hand, by interposing a urea-based resin adhesive, the PH5 material is neutralized while gradually releasing the acetic acid contained in the material as wood acid gas as it is heated and dried. The pH of the material is adjusted to within the neutralization range of 6 to 7.

The aggregate thus provided can be heat treated during processing to maximize the water content in the aggregate.
Within 13 o/wt, ideally within 3 to 5 o/wt, and even as much as possible to 0 o/wt, to eliminate any room for water vapor to occur in the subsequent resin molding with aggregate mixed in, and It prevents the wood acid contained therein from exfoliating and volatilizing to eliminate the possibility of acid gas generation, and is sufficiently neutralized to have a pH value of 6 to 7.

In the aggregate thus provided, wood acid, especially acetic acid gas, contained in the wood flour evaporates during impregnation and heat molding with the thermosetting resin material mainly consisting of urea resin. After being neutralized, the possibility of acid gas generation is effectively reduced compared to the aggregate used in the subsequent processing in which the aggregate is mixed into a resin material and molded.

In addition, most of the water contained in the aggregate is evaporated due to the heating and drying process applied during aggregate molding, so there is no generation of water vapor, which is considered to be a problem in resin molding using molded aggregate. , there is no room for foaming, cavities, rough skin, etc. to occur in the molded product. still,
Removal of this moisture content can also have a significant effect on the volatilization of the wood flour contained in the wood flour.
The wood acid contained in wood flour usually reacts with H ₂ O groups and is then exfoliated and volatilized, thereby effectively suppressing this. Therefore, the PH6 is reduced by eliminating and neutralizing the wood acid produced in the process of heat crushing and curing by impregnating the thermosetting resin material.
In addition to the adjustments in steps 7 to 7, the generation of residual wood acid gas from the aggregate was more effectively suppressed.

Effective elimination of wood acid gas in such aggregates,
Prevention of this occurrence has an extremely important meaning in subsequent resin molding. In other words, when wood acid gas is generated during resin molding, the cylinder screws of presses, extruders, and injection machines used for resin molding, or the inner wall surfaces of molds or molds, are oxidized and corroded, reducing their service life. This drastically reduces the frequency and also reduces the molding efficiency, causing the problem of molding defects due to uneven extrusion and injection pressures.

In addition, unlike ordinary pure wood flour, the surface resistance value of the aggregate is extremely reduced due to the hardening resin being impregnated or attached to the aggregate. The extrusion and injection pressure when mixed and molded into the material is almost similar to that of common resins. On the other hand, in the past, the mixing of wood flour caused the wood flour to come into sliding contact with the inner circumferential surface of the cylinder, die, etc., causing frictional resistance, and when extrusion was performed, the inner circumferential surface of the cylinder, die, etc. This causes scratches, wear, or damage on the circumferential surface.

Furthermore, the use of such aggregates ensures good compatibility with the mixed resin material, ensuring uniform mixing of the aggregates,
In addition, it is possible to eliminate as much as possible the voids that occur on the peripheral surface of the aggregate in the molded product, thereby making it possible to provide a molded product with the desired quality.

The calcium carbonate powder prepared next is used as needed to prevent molded products from deforming during extrusion processing, etc., and to keep the unit price of molded products low since calcium carbonate itself is particularly cheap. It is something that

In addition to these materials, stabilizers such as lead were separately prepared in an attempt to prevent deterioration in the molded product and to reduce as much as possible the frictional resistance that occurs during extrusion processing.

Furthermore, when the molded product is to be colored, a corresponding coloring agent is prepared. For example, when the molded product is made white, titanium oxide is mixed in.

A composite board 1 is produced by mixing the thus provided aggregate 1a into a resin dough 1b and extruding it using an extrusion device, with or without using a coloring agent.
The plates 1 and 1 are laminated and integrated so that the directions of extrusion during molding are perpendicular to each other, and there are two types of bonding: simple adhesive bonding and pressure bonding. And furthermore,
It was planned to perform fusion by heating and melting, and further to perform molding by heating at 100 to 140°C and then pressing at 20 to 50°C, as shown in FIG.

In the synthetic plywood provided by such a forming method, the following properties were observed. In other words, (1) It is said to have particularly good surface abrasion resistance, and has the following difference in the amount of wear compared to ordinary PVC materials and plywood materials, making it suitable for use as flooring materials, wall materials, etc., which are subject to severe wear. considered optimal.

Synthetic plywood 35.9 Hard PVC 46.6 Plywood 348.2 (However, load 1Kg, rotation speed 70rpm, wear wheel type CS-17 Calibrase mg/1000 rotations) (2) Low shrinkage and expansion rate during molding, and moreover, after molding Since there is no contraction or expansion change in the process, there is no warping or distortion of the plate itself, and a hard plate material can be supplied.

(3) Appropriate hygroscopicity is observed as shown in the water absorption rate below, and it is also water resistant, so it not only waterproofs the covered surface but also suppresses sweating, and also absorbs sweat from the skin surface that comes into contact with it. In particular, it promised a comfortable texture as wall material, flooring material, etc.

Synthetic plywood 0.51 Hard PVC 0.09 Plywood 7.9 (Water absorption rate per mg/cm ² according to JIS K7209 plastic water absorption test method) (4) Appropriate contact resistance occurs because aggregate 1a is exposed on the surface. It provides an optimal walking contact feeling as a flooring material, etc., and the presence of this aggregate 1a improves the adhesion of ink for surface decorative printing, etc., and promises the creation of good colors. Furthermore, as the aggregate 1a is exposed, the adhesive
It adheres strongly based on the base point, making it possible to bond PVC plates to each other, which was previously considered difficult.

(5) By having the aggregate 1a, the heat insulation and sound insulation functions are good, and the color development property of the board 1 is made good by having good compatibility with mixed pigments, etc.

(6) By mixing aggregate 1a, it has the same color tone and texture as ordinary wood, and it is possible to saw and nail during construction.

The synthetic plywood according to the present invention is expected to be used in a wide range of applications as a board material that is comfortable to the touch and has high abrasion resistance with little deviation. It is.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing the extrusion of the board 1, Fig. 2 is a plan view of the extruded board 1, Fig. 3 is a perspective view of the laminated boards 1 to 1, and Figs. 4 to 6 are cross-sectional views of the plywood. , FIG. 7 is an enlarged cross-sectional view of the plate 1. In addition, in the figure, 1... composite board, 1a... aggregate, 1b
...resin fabric, m...loose, n...dense, a...plywood.

Claims (1)

[Claims] 1. For crushed chips, pulp, rice husks, and other appropriate cellulose-based materials, the water content of the material is
The processed material is dried to within 15O/WT to induce collapse of the fiber structure, and the processed material is impregnated with a urea resin solution, and then the processed material is heated at 100°C to 250°C. A process of drying and crushing in a temperature range to form a neutralized finely hardened aggregate with a pH of 6 to 7, and a process of mixing this neutralized finely hardened aggregate into a thermosetting resin material such as vinyl chloride and extrusion molding. 1. A method for forming a wood-like synthetic plywood comprising the steps of: forming a synthetic board material, and laminating and bonding the synthetic board materials so that the extrusion directions of the board materials are sequentially orthogonal to each other. 2. A method for forming wood-like synthetic plywood according to claim 1, characterized in that the aggregate has a mesh size of 100 to 150 and a water content of 5 o/wt or less. 3. A method for forming a wood-like synthetic plywood according to claim 1, wherein the amount of the aggregate mixed is 5 to 40 o/wt to form a film-like synthetic board material. 4. A method for forming a wood-like synthetic plywood according to claim 1, characterized in that the mixed amount of the aggregate is 20 to 60 o/wt to form a sheet-like synthetic board material.