JPH08197514A - Manufacture of plate-like artificial wood having straight grain pattern - Google Patents

Abstract

PURPOSE: To facilitate manufacture of artificial wood wherein a straight grain pattern does not disappear even by surface polishing or the like by a method wherein the straight grain pattern approximating to that of natural wood is provided on a surface, and the straight grain pattern is distributed to an inside in a plate thickness. CONSTITUTION: After extruding tubularly a molding resin material in which a colored material is mixed with a circular die, it is cut open and developed to make plate-like artificial wood. In that case, an annular porous component having many bypass through holes is arranged in an annular resin passage the die, and extrusion is carried out. Thereby, a straight grain plate by a scoreline pattern wherein the colored material is oriented by development in a resin flow direction on a surface of an extrusion molded product and in its inside by using flow-straightening operation by the porous component is represented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a synthetic resin plate-like artificial wood having a grain pattern.

[0002]

2. Description of the Related Art Conventionally, as a method for producing artificial wood made of synthetic resin with a grain pattern, for example, Japanese Patent Publication No. 3-598.
As can be seen in Japanese Patent Publication No. 04-04, a molding resin material made of a thermoplastic resin mixed with wood powder is extruded into a tube shape with a round die, cut out in the length direction, and expanded into a flat plate shape. A method of forming a plate-like material by this is known.

However, in this conventional manufacturing method, it is not possible to impart a good grain pattern close to that of natural wood to the surface, and it is not possible to impart a high-quality grain pattern.

On the other hand, as a method for producing artificial wood having a grained pattern on the surface, as seen in Japanese Patent Laid-Open No. 62-117724, the inner peripheral surface of the resin outlet of the extruder is along the flow direction of the resin. By forming a large number of grooves, a large number of ridges are formed on the surface of the extruded molded product, and the ridges are crushed by a sizing former before cooling, so that a large number of ridges are continuous in the length direction. It has been proposed to provide a grain pattern consisting of the linear pattern.

However, in this method, since the ridges formed on the surface are crushed to form a streak pattern, not only the workability problem remains, but also the streak lines are uniform and too conspicuous. There was a problem that only a grain pattern with a poor natural feeling could be applied.

[0006] Against this background, the applicant of the present application discloses, in accordance with Japanese Patent Application No. 6-40186, a colorant particle such as brown for imparting a wood pattern as a molding resin material. In addition to using the mixed ones, a part of the inner or outer peripheral surface of the annular resin passage in the round die for extrusion shall be provided with uneven surface friction means, and the surface of the resin material A method has been proposed in which a pattern oriented in the extrusion direction of the coloring material is displayed on the surface of the molded product by giving a flow frictional resistance to give a grain pattern.

The above-mentioned prior proposed method was sufficiently satisfactory in the desired effect of imparting a grain pattern,
It was regrettable that it had the following problems.

[0008]

That is, the grain pattern formed by the above method is formed in an extremely shallow range of about 0.1 to 0.2 mm in depth only in the surface layer portion of the artificial wood. Nothing more.

Therefore, when the surface of the artificial wood is polished or cut depending on the application, the grain pattern may easily disappear. Not only that, in artificial wood molded using a round die, since the fusion strength is low in the spider part of the die, there is a possibility that tearing may occur during thermoforming such as vacuum forming or pressure forming, As a result, there was a problem that it was restricted in usage.

In view of such a problem, the present invention solves this problem further, and has a uniform grain pattern almost entirely in the thickness direction of the plate-like artificial wood, and disappears even by surface polishing. An object of the present invention is to provide a manufacturing method capable of obtaining a plate-shaped artificial wood that has a grain pattern that does not occur and that does not break during thermoforming.

[0011]

As a method for achieving the above object, the present invention is an extruder using a round die for molding resin material mixed with a coloring material for imparting a wood grain pattern. After extruding into a tube having a predetermined diameter by means of a method of obtaining an artificial wood in the form of a plate by opening and opening the extruded tube in a part of the circumferential direction, one of the circular resin channels in the circular die is used. In the part, an annular porous member having a large number of diversion through-holes oriented in the flow direction of the resin material is interposed, and the resin material for molding is once diverted through the diversion-through holes, and then in the process of reaching the die outlet. A gist of the method for producing a plate-shaped artificial wood having a grain pattern is characterized in that a tube having a grain pattern is extruded over substantially the entire wall thickness by re-focusing and fusing together.

[0012] In a preferred embodiment, the flow-dividing through holes are provided in at least two rows inside and outside the annular resin flow path in the round die and in a zigzag arrangement between adjacent rows. The annular porous member,
It is recommended that the circular die be provided at a position in the vicinity of the maximum diameter portion of the annular resin flow path in the die.

The molding resin material used in the present invention is a mixture of a thermoplastic synthetic resin and wood powder, preferably a base material, and a coloring agent such as brown for forming a wood grain pattern. It is a thing.

The thermoplastic resin is not particularly limited, but specifically, for example, polyvinyl chloride resin (PVC), acrylonitrile / butadiene / styrene copolymer resin (ABS), polystyrene resin (P).
S), polypropylene resin (PP), etc. are used. Further, the wood powder has a particle size of 80 to 300 mesh and a water content of 1 to 5
% Is preferably used. The blending amount is preferably about 10 to 100 parts by weight of wood powder, and particularly preferably 30 to 70 parts by weight with respect to 100 parts by weight of the thermoplastic resin.

The colorant is composed of a thermoplastic resin powder or pellets colored in a darker color than the base material made of a mixture of the above resin and wood powder, and has a good compatibility with the resin of the base material. It is preferable to use the same one that has. As an example of the brown colorant, for example, "WR-PVC, W-3 manufactured by Central Glass Co., Ltd.
2C, H244 ”(trade name) can be listed as a suitable item. The mixing ratio of the coloring material is 10
0 to 6 parts by weight, particularly preferably 3 to 5 parts by weight
Good results can be obtained by adjusting the amount to about parts by weight.

The plate-shaped artificial wood according to the present invention is produced by using the above-mentioned molding resin material and once using an extruder (1) equipped with a round die (2) as shown in FIG. Then, the extruded tube (10) is cut in a part in the circumferential direction by a cutting blade (3) at a position near the exit of the die, and the cut tube (10) is opened in a developed state to form a plate-shaped artificial wood (P). It is to be molded into. After the expansion, it is desirable to further pass through a hot roll to carry out a stabilizing treatment in order to remove the stress strain remaining inside.

In the above extrusion molding, the present invention is directed to a part of the annular resin flow path (4) in the round die (2) equipped in the extruder (1) in the flow direction of the resin material. An annular porous member (5) having a large number of flow dividing through holes (6) is arranged in between. The annular porous member (5) is used to support the topede (7) in the round die (2).

As a result, the resin material kneaded by the screw (9) in the cylinder (8) of the extruder (1) is sent to the round die (2) through the adapter (11), and the topeede (7). Is introduced into the annular resin flow channel (4) whose inner surface side is defined by the expanded tapered inlet (4a) side, and in the process of passing through the flow channel, the branch flow through hole (5) of the annular porous member (5). According to 6), it is once divided into a large number of independent rod-shaped streams. Then, as the annular resin flow path (4) reaches the outlet (4b) side where the diameter is gradually reduced, the divided resin material is refocused, fused and integrated, and extruded into a tube shape.

Therefore, in the resin material, when the resin material is divided into the flow dividing through holes (6) of the porous member (5), the coloring material contained in the resin material is stretched and oriented in the resin flow direction, and the coloring material remains even after the convergence and integration. The shunt (10a) remains in the entire thickness of the peripheral wall of the extruded tube (10), and the grain pattern (A) is formed not only on the front and back surfaces but also inside. Therefore,
The plate-like artificial wood (P) after being developed also has the grain pattern (A) not only on the front and back surfaces but also over substantially the entire thickness direction.

By the way, the branch flow through hole (6) of the annular porous member (5) is provided with a good grain pattern (A) close to that of natural wood, even if it is too large or, conversely, too small. Is difficult. Therefore, in the case of a circular hole, its diameter is preferably in the range of 3 to 15 mm, particularly preferably 5 to 10 mm. The shape is not limited to the circular hole, and it may be formed in a different shape such as a square, a polygon having five or more sides, or a gourd.

The through holes (6) may have different sizes and shapes mixedly. In this case, the surface of the artificial wood can have a grain pattern in which the spacing of the streaks is irregularly changed, and the grain pattern can be made more similar to the grain pattern of natural wood. Furthermore, the through holes (6) may be provided in a line in the circumferential direction in the resin flow path as shown in FIG. 3, but the strength of the plate-like artificial wood in the width direction is made uniform, In order to improve the thermoforming processability and make the grain pattern closer to the grain pattern of natural wood, the through holes (6) are formed in the resin flow path (4) in the porous member (5) in two rows inside and outside. It is desirable to provide them in three or more rows, and staggered arrangement between adjacent rows. FIG. 3 shows an example of staggered arrangement in the inner and outer two rows, and FIG. 5 shows an example of staggered arrangement in the three rows. In each case, the plate-shaped artificial wood (P) to be formed has a zigzag laminated stack of resin material rod-shaped diversion marks (10a) due to through holes (6) in its cross section, as shown in FIGS. 6 and 8. It remains in the arrayed state and has a grain pattern (A) in the entire thickness direction.

By virtue of the arrangement configuration of the through holes (6) as described above, the open area ratio in the resin flow path (4) in the annular porous member (5) is at least 25% or more, particularly preferably 40 to 60. It is desirable to set it in the range of about%. When the porosity is less than 25%, the extrusion pressure is undesirably increased. On the other hand, if the porosity exceeds 60%, the strength of the annular porous member becomes weak and the extrusion pressure cannot be endured, which is not preferable in terms of mechanical design.

On the other hand, the mounting position of the annular porous member (5) is
In the annular resin flow path (4) in the die (2), it is preferable to set it at the maximum diameter portion with the largest diameter or at least in the vicinity thereof. If it is set too close to the entrance (4a) side, it will be difficult to give a good grain pattern. On the contrary, if it is too close to the outlet (4b) side, the mechanical strength such as bending strength and impact strength of the manufactured plate-like artificial wood may be weak, and the surface texture of the grain pattern (A) may be adversely affected. I am concerned about giving.

[0024]

EXAMPLE As a molding resin material, 100 parts by weight of a polyvinyl chloride resin and 30 parts by weight of a dry wood powder having an average particle size of 100 μm were mixed with 100 parts by weight of a base material, and a brown colorant (central glass) was used. Co., Ltd. "W
R-PVC ") 4 parts by weight were mixed.

On the other hand, as an extruder, the bore diameter is 55 mm, L / D
= 18 twin-screw extruder was used and equipped with a round die. The circular die has a large number of shunt through holes (circles with a hole diameter of 7 mm) arranged in two rows in the inner and outer rows and in a staggered arrangement in the intermediate portion corresponding to the maximum diameter portion of the annular resin passage inside the circular die. An annular porous member having a thickness of 50 mm formed by being drilled to 50% was incorporated.

The resin material was extruded into a tube having a diameter of 200 mm and a wall thickness of 3 mm by the above extruder. The extrusion conditions are as follows: extruder hopper temperature 170 ° C, cylinder outlet temperature 175 ° C, screw temperature 170 ° C, adapter temperature 175 ° C, round die temperature 180 ° C, screw rotation speed. 20rp
set to m.

Next, the molded tube extruded from the round die is cut open at one location in the circumferential direction by a cutting blade provided in the vicinity of the die outlet, developed into a sheet, and then allowed to cool and harden to give a plate having a thickness of 3 mm. A shaped artificial wood product was obtained.

The artificial wood had a beautiful grain pattern on both the front and back sides, which was similar to the grain pattern of natural wood, and the grain pattern was distributed throughout the thickness direction. .

Then, when the surface of the artificial wood was ground to a depth of 1.0 mm on average, a good grain pattern was always present on the surface while slightly changing the pattern form.

[0030]

Industrial Applicability According to the present invention, artificial wood having a beautiful grain pattern similar to the grain pattern of natural wood on the surface thereof can be efficiently produced by the extrusion method according to the above-mentioned conditions. The pattern can be distributed not only on the surface portion but also on the inside in the plate thickness direction so that the grain pattern does not disappear even if surface polishing is performed. Therefore, general wood processing such as surface polishing and cutting, molding processing performed on the thermoplastic resin plate, and the like can be added without any trouble, and the range of applications can be expanded.

Further, according to the second aspect, it is possible to obtain the artificial wood which is free from the risk of breaking during thermoforming.

Further, according to the third aspect, it is possible to obtain an artificial wood having a fine grain pattern with a good surface skin.

[Brief description of drawings]

FIG. 1 is a schematic vertical sectional view of an extruder used for carrying out the present invention.

FIG. 2 is a perspective view showing a mode in which an extruded tube is cut open and developed into a plate shape.

FIG. 3 is a front view of an annular porous member equipped in an extrusion die.

FIG. 4 is a conceptual sectional view schematically showing a sectional structure of an extrusion molded article using the annular porous member of FIG.

FIG. 5 is a front view of a modified example of the annular porous member.

6 is a conceptual cross-sectional view schematically showing the cross-sectional structure of an extrusion-molded product when the annular porous member of FIG. 5 is used.

FIG. 7 is a partial front view of still another modified example of the annular porous member.

8 is a conceptual cross-sectional view schematically showing the cross-sectional structure of an extrusion-molded product when the annular porous member of FIG. 7 is used.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Extruder 2 ... Round die 3 ... Cutting blade 4 ... Annular resin flow path 5 ... Annular porous member 6 ... Dividing flow through hole 10 ... Extrusion tube P ... Plate-shaped artificial wood A ... Grain pattern

Claims (3)

[Claims] 1. A molding resin material mixed with a coloring material for imparting a wood grain pattern is extruded into a tube having a predetermined diameter by an extruder using a round die, and the extruded tube is circumferentially formed. In the method for obtaining a plate-shaped artificial wood by cutting and expanding with a part of a ring, a part of the circular resin flow path of the round die has a plurality of shunt through-holes oriented in the flow direction of the resin material. By interposing a porous member, the molding resin material is once diverted through the diverting through hole, and then converged, fused and integrated again in the process up to the die outlet, thereby forming a grained pattern on almost the entire wall thickness. A method for producing a plate-shaped artificial wood having a grain pattern, which comprises extruding a tube having the grain. 2. The split flow through holes are provided in at least two rows inside and outside the annular resin flow path and in a zigzag arrangement with respect to each other between adjacent rows. A method for producing a plate-shaped artificial wood having a grain pattern. 3. The perforated pattern according to claim 1, wherein the annular porous member is provided at a position in the vicinity of the maximum diameter part of the annular resin flow path in the round die. A method for manufacturing a plate-shaped artificial wood having the same.