JP2002187116A - Timber and thermoplastic resin composite material for coating of woodgrain pattern - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a timber and thermoplastic resin composite material for coating of a woodgrain pattern having convenience capable of obtaining a color, a gloss and a sense of a peculiar ruggedness on a woody surface similar to those of a woodgrain of a natural tree merely by executing a simple coating work and coating a favorite color by a user and to provide a method for forming the woodgrain pattern similar to the woodgrain of the natural tree. SOLUTION: The method for forming the timber and thermoplastic resin composite material for coating of the woodgrain pattern comprises a first grinding step of forming many woodgrain-like ground grooves 7 on a surface of a molding 1 of the timber and thermoplastic resin composite material by using a grinding sheet on which abrasive grains of a grain size of 24 to 60 are fixed, then a second grinding step of grinding vertex parts 8 of rising strips between the many grooves formed in the previous step by a grinding sheet in which abrasive grains of a grain size of 100 to 400 are fixed, and then a step of removing fluffing of the vertex parts by using a metal brush, buffing or the both to form a polished surface in which absorption of a paint is suppressed to form the timber and thermoplastic resin composite material in which fluffing 10 is retained in a depth (p) of each of the deep grooves 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wood / thermoplastic resin composite for wood grain pattern coating, a method for producing the same, and a method for forming a wood / thermoplastic composite wood grain pattern.

[0002]

2. Description of the Related Art In general, wood powder and a thermoplastic resin are used in order to suppress the water absorption of wood materials and the decomposability due to microorganisms or to reuse (recycle) wood powder produced as a by-product during wood processing. A composite material obtained by manufacturing a wood flour compound obtained by kneading the compound and extruding or injection molding the same is known.

The products to which the composite material can be applied include furniture,
Examples include architectural semi-finished products such as window frames, door panels, and interior panels, storage or transport containers, pallets, fences, household furniture, and exterior wall decorative materials.

[0004] As a method of forming a grain pattern on the surface of a wood / plastic composite material formed by compounding plastic and wood material, conventionally, a surface is fixed by using a rotary grinding and polishing device such as a belt sander. By shaving in the direction, the surface layer where the content ratio of the resin component is higher than the average is scraped off, so that a standard layer with the content ratio of the resin component appears, and at that time, the grinding method is selected and the unevenness consisting of scratches In some cases, a wood grain pattern decoration method in which a part resembles a wood grain is employed.

Japanese Patent Application Laid-Open No. 8-267597 discloses that 100 parts by weight of a polyolefin resin and 20 to
The surface of the polyolefin resin plate containing 200 parts by weight is coated with a wrapping material having a particle size of 30 to 100 or the like for 10 to 100
By shaving off a thickness of 0 μm, a surface roughness of 5-2
A technique capable of obtaining a straight grain pattern in a range of 00 μm is described.

Japanese Patent Application Laid-Open No. 9-216500 discloses that, as a first step, the surface of a wooden synthetic board composed of 35 to 80% by weight of a thermoplastic resin molding material with respect to 20 to 60% by weight of a cellulosic crushed product. A deep scratch is formed by sanding of 40 to # 60, a coloring material is applied as a second step, and a new shallow wound is formed while leaving a concave portion applied to the deep wound by sanding of # 100 to # 150 as a third step. In addition, wood grain printing is performed as a fourth step, and a transparent paint for finishing is applied as a fifth step, whereby a pattern having a deep woody texture is formed due to a synergistic action of the wood grain pattern by sanding and the wood grain pattern by printing. It is stated that.

[0007]

However, the method described in Japanese Patent Application Laid-Open No. 8-267597, which is a conventional method of forming a grain pattern of a wood / thermoplastic resin composite material, is simpler than that of a natural wood grain. A poor sanding pattern results in a poor product. After coating, the paint penetrates the entire surface, and the surface and the grinding groove are colored with the same density, and the wood grain becomes almost inconspicuous.

Further, even if the raw wood flour used is of a fine particle size, the surface of the product (composite material) is often fuzzy,
There is also a problem that even when a transparent paint such as a varnish as a finishing material is applied, the luster and feel are not the same as those of natural wood.

Further, Japanese Patent Application Laid-Open No. Hei 9-2165,
In the technique described in Japanese Patent Publication No. 00, there is a synergistic effect between the two sandings and the grain pattern formed by painting applied between them and the grain pattern by printing, but the complicated manufacturing process and high cost are disadvantages. As a result, it is not practical and not only difficult to apply to a molded article having a complicated shape, but also because the grain is printed in advance, the user cannot paint in a desired color.

The printing base obtained by shallow sanding of No. 100 to 150 is suitable for gravure printing or the like, but even if a fine wood particle is used as a raw material, many fluffs are formed, and There is also a problem that the luster and feel are considerably inferior to natural wood even after the application of the transparent paint in the process.

Accordingly, an object of the present invention is to solve the above-mentioned problems and to provide a simple wood / thermoplastic resin composite material having the same color, luster, and unique texture on the wooden surface as the grain of natural wood. It is a wood-thermoplastic composite material for coating with a convenient wood grain pattern that can be obtained simply by performing a painting operation and that can be painted in a color desired by a user.

Further, in the invention according to the method for producing a wood / thermoplastic resin composite material having a woodgrain pattern according to the present invention, a wood / thermoplastic resin composite material having a woodgrain pattern capable of solving the above-mentioned problems can be surely and efficiently obtained. It is to provide a method of manufacturing.

Further, according to the invention of the wood / thermoplastic resin composite material of the present invention, the wood / thermoplastic resin composite having the same color, luster and unique unevenness on the wooden surface as the wood of the natural wood. An object of the present invention is to provide a method of forming a wood grain pattern that can reliably obtain a material by a method as simple as possible.

[0014]

In order to solve the above-mentioned problems relating to the wood / thermoplastic resin composite material for wood grain pattern coating, the present invention relates to a wood / thermoplastic resin molded from a mixture of wood and a thermoplastic resin. On the surface of the composite material, a large number of grinding grooves formed of linear contact marks of grinding abrasive grains are formed in a grain shape, and the tops of the ridges formed between the grinding grooves are ground and polished to obtain the tops. The fluff of the part is removed to suppress the penetration of the paint, and the wood for painting with a wood grain pattern consisting of a grind surface with fluff left inside the grinding groove.
This is a thermoplastic resin composite.

The wood / thermoplastic resin composite material for wood grain pattern coating of the present invention configured as described above is formed between the grinding grooves when the paint is applied to the surface by brushing or spraying. The tops of the ridges are painted in a light color, and the deeper the inner part of the grinding groove, the more the paint is soaked and painted in a darker color. That is, the wood / thermoplastic resin composite material for wood-grained coating of the present invention is colored into a woodgrain pattern having a high contrast of light and shade by the usual uniform coating on the entire surface. The other parts are colored in a pale color to form an extremely woody color difference and a glossy pattern at important points.

In order for the wood / thermoplastic resin composite material for coating of the present invention to be colored into a wood pattern having a high contrast of shading as described above, the surface roughness of the top of the ridge from which fluff has been removed is required. Is preferably Rmax10 to 40 μm, and the surface roughness when a grinding groove is formed is Rmax6.
It is preferably from 0 to 300 μm.

Further, in order to solve the problem relating to the method for producing a wood / thermoplastic resin composite material for wood grain pattern coating, the present invention provides a method for producing a wood / thermoplastic resin composite material having a particle size of 24 to 40%. No. 60 (JIS R 6001 or J
A first grinding step of forming a large number of wood-like grinding grooves is performed using a grinding sheet in which the abrasive grains of IS R 6010) are fixed, and then the tops of the ridges between the multiple grinding grooves formed in this step are formed. With a particle size of 100 to 400 (JIS R 60
01 or JIS R 6010) is subjected to a second grinding step of grinding the grinding grooves formed in the first grinding step to such an extent that the grinding grooves formed in the first grinding step are not completely erased. Alternatively, by using both of them, the fuzz on the top is removed to form a polished surface in which the penetration of the paint is suppressed, and the wood for coating of wood grain pattern, This is a method for producing a plastic resin composite material.

The surface roughness of the composite material having the grinding grooves formed after the first grinding step is Rmax 60 to 300 μm,
The surface roughness of the top of the ridge from which fluff has been removed after the second grinding step is preferably Rmax10 to 40 μm.

When manufactured as described above, in the first grinding step, a large number of ground grooves are formed in a grain shape in a line shape which is easy to adhere to a large amount of paint. Then, in the second grinding step, the tops of the ridges are removed, and then the fuzz on the tops is removed using a metal brush. Therefore, the wood-like uneven surface having the ridges in which the penetration of paint is suppressed is provided. Is obtained.

The wood / thermoplastic resin composite material for coating in which the grinding grooves and the ridges are formed as described above is formed between the grinding grooves when the paint is applied to the surface with a brush or a spray. The tops of the ridges are painted pale.

In other words, according to the method of the present invention, the deeper the inner part of the grinding groove, the more the paint adheres and the paint is applied in a darker color, the grain of the grain is darker, and the parts other than the grain are lightly colored and very grainy. A wood / thermoplastic resin composite material for coating can be manufactured in which color differences and glossy patterns are formed at important points.

Further, in order to solve the problems of the invention relating to the method for forming a grain of the above-mentioned wood / thermoplastic resin composite material, according to the present invention, the particle size of the wood / thermoplastic resin composite material is 24 to No. 60 (JIS R 6001 or J
A first grinding step of forming a large number of wood-like grinding grooves is performed using a grinding sheet in which the abrasive grains of IS R 6010) are fixed, and then the tops of the ridges between the multiple grinding grooves formed in this step are formed. With a particle size of 100 to 400 (JIS R 60
01 or JIS R 6010) is subjected to a second grinding step of grinding the grinding grooves formed in the first grinding step to such an extent that the grinding grooves formed in the first grinding step are not completely erased. Or, using both, the fuzz on the top is removed to form a polished surface in which the penetration of the paint is suppressed, and the fuzz is left behind the grinding groove, and then the wood / thermoplastic resin is applied. This is the method of forming the wood grain pattern of the composite material.

According to the wood grain pattern forming method described above, the first
In the grinding step, a large number of grinding grooves are formed in a linear shape that is easy to stain with a large amount of paint, and in the second grinding step, grain having ridges is obtained. Thereafter, when the fuzz on the top is removed using a metal brush or buff or both, when the paint is applied by brush or spray, the top of the ridge between the grinding grooves is painted in a pale color. Therefore, the grain of the wood is darkly colored, and the portion other than the grain is colored with a light color, so that a pattern having a color difference that is very grainy can be formed in the wood / thermoplastic resin composite material.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION A molded article of a wood / thermoplastic resin composite material used in the present invention is obtained by molding a mixture of a thermoplastic resin such as a polyolefin resin and a woody powder. It is desirable to use a resin that is easy to mix with wood flour and has good adhesiveness. In addition to polyolefin resins such as polyethylene, polypropylene, and polybutene, vinyl chloride resin, which is a resin with high polarity, and a mixture of polyvinyl alcohol and vinyl acetate resin are used. Often done.

The thermoplastic resin preferably has a melt index of 0.1 to 200 g / 10 min, more preferably 0.5 to 50 g / 10 min. If the value is lower than the above range, the load on the kneader becomes large and kneading cannot be performed sufficiently. If the value is higher than the above range, the mechanical strength decreases, which is not preferable.

The wood may be any of a powdery or granular woody material obtained by cutting, cutting or pulverizing a wooden board for recycling, and a powdered or granular material of sawn wood. Examples of the wood board include plywood, particle board, MDF, OSB, and other engineering wood. The type of wood may be either coniferous or hardwood, and may be bamboo or chaff.

The size of the powdery wood material is not particularly limited, but cutting powder or cutting powder having a size of 1 mm or less, or powder having a size of 300 μm or less obtained by pulverizing them is appropriate. There is no problem even if the surface of the wood material has been improved in dispersibility or affinity by a well-known physical or chemical treatment (surface chemical treatment).

The mixing ratio of the wood is 25 to 400 parts by weight based on 100 parts by weight of the thermoplastic resin. It is not preferable that a composite material containing a small amount less than the above-mentioned predetermined range is not obtained because a sufficient woody feeling cannot be obtained. Further, if the amount is more than the above-mentioned predetermined range, the fluidity becomes poor, and the kneading efficiency is remarkably reduced, which is not preferable.

The molding method is not limited to extrusion molding, but injection molding or compression molding can also be employed.
It goes without saying that the form of the molded body is not particularly limited.

A method for producing a wood / thermoplastic resin composite material for coating a woodgrain pattern of the present application and a method for forming a woodgrain pattern for a wood / thermoplastic resin composite material will be described below step by step with reference to the accompanying drawings.

As shown in FIGS. 1 and 2, it is preferable to use a well-known belt sander in the first grinding step of forming a large number of grain-shaped grinding grooves on the molded body 1 using a grinding sheet. .

Incidentally, the belt sander has an endless annular belt 3 wound around a roller 2 of a belt transmission mechanism so as to be rotated by a driving force of a motor or the like. Is fixed on the conveyor 5
This is to be pressed against the surface of the upper molded body 1.
The plate-like molded body 1 comes into contact with the surface (polishing surface) of the belt 3 while being forcibly transported by the placed and fixed conveyor 5, and is subjected to the grinding and / or polishing action by the abrasive grains 4 having a predetermined particle size. .

In the belt sander at the time of grinding, the positional relationship between the workpiece and the belt may shift in the width direction (the direction of the right and left arrows in FIG. 1), and the shift width at that time may be uneven in the grain. The bend forms a natural woodgrain.

When the belt sander is operated, the belt 3
When the belt is shifted in the width direction by a predetermined limit or more, the belt is corrected in the width direction by the shift return mechanism provided in the belt sander and returned to the initial position. The wood grain is formed on the surface of the molded body 1 thus ground in a pattern that is shifted in the width direction as shown by a thick vertical line in FIG.

As a grinding method using a grinding sheet having abrasive grains fixed thereto according to the present invention, in addition to using a belt sander, a well-known rotating method in which abrasive grains are bonded to the surface of a rotating disk or cylinder via a sheet is used. Grinding and polishing equipment and sand papering machines (drum sanders as well as belt sanders,
There is a grinder and the like. ) Can also be used.

As shown in FIG. 3, the grain size is 24 to 60 (J
IS R 6001: General-purpose particle size, or JIS R
6010: When the first grinding step is performed with a belt sander using a grinding sheet to which abrasive grains of (polishing cloth paper grain size) are fixed, the resin-rich (high resin content ratio) skin layer 6 on the surface of the molded body 1 Is ground to form a rough ground surface (preferably Rmax60) having a large number of grinding grooves 7 comprising linear contact marks of ground abrasive grains.
３００300 μm).

The abrasive grains to be used have a grain size of 24 to 60 (JI
SR 6001 or JIS R6010) is adopted. The reason for this is that natural abrasiveness cannot be obtained by using such abrasive grains having a large particle size smaller than the predetermined particle size or a small particle size exceeding the predetermined particle size.

As shown in FIG. 4, in the next step, a particle size of 10
No. 0 to 400 (JIS R 6001 or JIS R
The second grinding step is performed by a belt sander using a grinding sheet to which the abrasive grains of 6010) are fixed. In this way, the top 8a of the ridge 8 is ground to form a surface having a relatively uniform height (preferably Rmax10 to 40 μm).

Thereafter, as shown in FIG. 5, when the flat surface 9 is ground and polished using a metal brush, a linear grinding groove 7a shallower than the grinding groove 7 is formed and a deeper grain It becomes a pattern and the upper corner q of the grinding groove 7
The relatively large fuzz 10 existing on the flat surface 9 and the flat surface 9 is removed, thereby forming a surface in which the penetration of the paint is suppressed. Also, the deeper the inner part of the grinding groove 7, the more the fluff 10 remains, and the deeper the part, the more easily the paint permeates. Note that reference numeral 11 in FIG. 5C indicates relatively small fluff.

Due to the size of the fuzz and the difference in density (density), the paint is relatively easy to penetrate into the inner part of the grinding groove 7 when painting, and the surface of the upper corner q of the grinding groove 7 and the surface Since the paint is less likely to seep into the smooth surface 9, the contour of the grinding groove 7 is clearly visible, and a more grainy pattern is obtained.

As shown in FIG. 6, a more preferable method for producing a wood / thermoplastic resin composite material for coating a wood grain pattern or forming a wood grain pattern is to perform brushing with a metal brush and then buff. By buffing, relatively small fuzz 11 is removed from the surface of the upper corner q of the grinding groove 7, the flat surface 9 and the surface of the relatively shallow grinding groove 7a.

By doing so, the upper corner q of the grinding groove 7
Surface and the flat surface 9 and the relatively small grinding groove 7a
Has a smoother, more tactile feel and a more glossy surface than just ground and polished with a metal brush, and is a polished surface in which the penetration of paint is further suppressed.

The coating used in the present invention may be any known coating, depending on the mixing ratio between the thermoplastic resin and the wood.
An appropriate coloring agent can be selectively adopted.

For example, as a stain (base color type) paint, oil stain, aqueous stain, solvent stain,
Alcohol stain and the like. Examples of the coating (coating-colored type) paint include urethane, acrylic, urethane acrylate, lacquer, aminoalkyd, and the like. More preferred are stain-based paints.

Of course, a transparent paint for giving a gloss to the surface may be used. Examples of such a transparent paint include urethane, acrylic, urethane acrylate, lacquer, aminoalkyd, varnish and the like.

By performing the first and second grinding steps and the predetermined polishing step as described above, and then painting, as shown in FIG. The pattern can be made of wood / thermoplastic composites.

[0047]

[Examples and Comparative Examples] [Comparative Example 1] Polypropylene 1
00 parts by weight and 100 parts by weight of wood powder of 1 to 200 μm were mixed to produce a 19 mm thick plate formed by extruding this compound, and the surface thereof was used as a first grinding step. A 0.4 mm thickness is ground from the surface with a Kikugawa Iron Works), and as a second grinding step, it is repeated in the same direction with a 240-grain belt sander three times in 0.2 mm increments, and a total thickness of 0.6 mm is ground. A test piece of a wood-thermoplastic composite material for painting with a wood grain pattern was manufactured.

In the above, the grinding speed of the belt sander is 800 m / min, and the work feed speed is 5 m.
/ Min.

Oil stain was applied to the obtained test piece. However, since the entire surface was fluffy, after the coating, the coating permeated the entire surface and was uniformly and deeply colored. Not formed. A glossy transparent urethane was applied on top of the oil stain application, but there was much soaking and no gloss.

[Comparative Example 2] The same procedure as in Comparative Example 1 was conducted except that the grinding thickness in the second grinding step was changed to 0.2 mm. Pieces were produced.

An oil stain was applied to the obtained test piece. However, since the entire surface was fluffy, the coating penetrated the entire surface after coating, and the surface portion and the grinding groove portion were colored with the same density. It became a plain plate with no gloss, and the deep grinding grooves obtained in the first step were dimly visible as dark stripes compared to the surface, but the contrast was low and the outline of the stripes was not clear, so the wood grain pattern Did not look like In addition, glossy transparent urethane was applied on top of the oil stain application, but there was much penetration and no gloss was produced.

Example 1 100 parts by weight of polypropylene and 100 parts by weight of wood powder of 1 to 200 μm were mixed and extruded. Thunder (Kikukawa Iron Works)
The surface is ground to a thickness of 0.4 mm, and the second grinding step is performed in the same direction with a belt sander with a grain size of 240 mm in the same direction.
In the third step, the surface is brushed in the same direction using a stainless steel brush with a brush thickness of 0.3 mm in the same direction, and a test of wood / thermoplastic resin composite material for wood grain coating is performed. Pieces were produced.

In the above, the grinding speed of the belt sander is 800 m / min, and the work feed speed is 5 m.
/ Min.

An oil stain was applied to the obtained test piece. Compared with Comparative Examples 1 and 2, the flat surface 9 obtained in the second grinding step and the deep ground groove obtained in the first grinding step were compared. After the coating, the upper corner q, the flat surface 9 and the shallow grinding grooves 7a become pale and glossy, and the deep grinding grooves are formed. The contour became clear and the deep part p of the deep grinding groove 7 was deeply colored. As a result, the contrast of the grain pattern became high and the contour became clear, resulting in a realistic and beautiful grain pattern.
Further, a deep grain pattern was obtained due to the synergistic effect of the deep grinding grooves 7 in the first grinding step and the shallow grinding grooves 7a in the third grinding step. Also, as a result of applying glossy transparent urethane,
The outermost surface has a luster close to that of natural wood painting.

[Example 2] In the same manner as in Example 1, except that the surface buffing was carried out using a cotton cloth buff as the fourth step after the third step, the wood-grain coating wood and heat were used. Test specimens of the plastic composite were produced.

Oil stain was applied to the obtained test piece. Compared with Example 1, the flat surface 9 obtained in the second grinding step and the deep grinding groove 7 obtained in the first grinding step were compared with those in Example 1. The small fuzz on the surface of the upper corner q was completely removed. Therefore, after painting, the color of the upper corner q, the flat surface 9 and the shallow grinding groove 7a became lighter, and the profile of the deeper and more glossy grinding groove became clear. The deep part p of the grinding groove 7 was darkly colored, so that the contrast of the grain pattern became high, and the outline became clear, resulting in a realistic and beautiful finish. Further, as a result of applying a glossy transparent urethane, the surface became glossy more like a natural wood.

[Example 3] In the same manner as in Example 1, except that the surface buffing was performed using a cotton cloth buff instead of the metal brushing in the third step, the wood and heat for wood grain pattern coating were used. Test specimens of the plastic composite were produced.

Oil stain was applied to the obtained test piece. Compared with Examples 1 and 2, the flat surface 9 obtained in the second grinding step and the deep grinding obtained in the first grinding step were compared with those in Examples 1 and 2. Since the fuzz at the top formed by the surface of the upper corner q of the groove 7 was almost removed, the upper corner q
And the color of the flat surface 9 is thinner and glossier, the contour of the deep grinding groove 7 is clearer and
Due to the deep coloration, the grain pattern became higher in contrast and the outline became clearer, giving a realistic and beautiful finish.

Since the grain pattern was obtained only by the first grinding step and did not have a synergistic effect with metal brushing as in the second embodiment, the grain pattern has a little depth compared to the first and second embodiments. I felt like that. Further, as a result of applying the glazed transparent urethane, the surface became more lustrous close to a natural wood.

[0060]

According to the invention relating to the wood / thermoplastic resin composite material for wood grain pattern coating, as described above, the surface of the wood / thermoplastic resin material is formed from the linear contact marks of the abrasive grains. In addition to forming a large number of grinding grooves in a grain shape, removing the fuzz at the top of the ridge to suppress the penetration of paint in that part, and having the fuzz easily penetrating the paint inside the grinding groove Since the ground surface is left, there is an advantage that, by ordinary uniform coating on the entire surface, a wood pattern having a high contrast of light and shade is colored, and a very natural wood grain color difference and a glossy pattern are formed at important points.

The above-mentioned advantages are particularly remarkable in the coating wood / thermoplastic resin composite in which the surface roughness of the grinding groove and the surface roughness of the top of the ridge are within predetermined ranges.

Further, in the invention according to the wood grain forming method of the wood / thermoplastic resin composite material, the first grinding step includes the following steps:
After the second grinding step, a flute is completely removed by using a metal brush, more preferably a buff in combination, to form a ridge polished surface in which the penetration of paint is sufficiently suppressed, and a deep portion of the grinding groove is formed. Has a large amount of paint and leaves fuzz that tends to stick, so when paint is applied with a brush or spray, a very grainy color difference and glossy patterns are formed at important points, and the top of the ridge The part has very little fluff on the surface, has a smooth and tactile feel, and can form an extremely woody color tone difference and a glossy woodgrain pattern on the wood / thermoplastic resin composite material.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a mounting state of a wood / thermoplastic resin composite material to a belt sander.

FIG. 2 is a schematic explanatory view of a belt sander.

FIG. 3 is a cross-sectional view of a wood / thermoplastic composite material after a first grinding step.

FIG. 4A is a cross-sectional view of the wood / thermoplastic composite material after the second grinding step. FIG. 4B is an enlarged cross-sectional view of the wood / thermoplastic resin material after the second grinding step.

FIG. 5A is a cross-sectional view of the wood / thermoplastic composite material after being polished with a metal brush. FIG. 5B is an enlarged cross-sectional view of a main part of the same.

FIG. 6 (a) is a cross-sectional view of a wood / thermoplastic composite material after being polished with a buff; (b) is an enlarged cross-sectional view of an essential part of the above;

FIG. 7 is a plan view of a wood / thermoplastic composite material after painting.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Molded body 2 Roller 3 Belt 4 Abrasive grain 5 Conveyor 6 Layer rich in resin 7 Deep grinding groove 7a Shallow grinding groove 8 Ridge 8a Top part before being ground flat 9 Flat surface 10 Large fluff 11 Small fluff p Back q top corner

Claims (4)

[Claims] 1. A wood-thermoplastic resin composite obtained by molding a mixture of wood and a thermoplastic resin, a large number of grinding grooves formed of linear contact marks of grinding abrasive grains are formed in a grain shape,
The top of the ridge formed between these grinding grooves is ground and polished to remove the fuzz on the top to suppress the penetration of the paint, and the inside of the grinding groove has a fuzzy ground surface. A wood / thermoplastic composite for painting with a wood grain pattern consisting of the leftovers. 2. The wood / thermoplastic resin composite material for wood grain pattern coating according to claim 1, wherein the surface roughness of the top of the ridge from which fluff has been removed is Rmax 10 to 40 μm. 3. A large number of grain-like grinding using a grinding sheet in which abrasive grains having a grain size of 24 to 60 (JIS R 6001 or JIS R 6010) are fixed on the surface of a molded article of a wood / thermoplastic resin composite material. A first grinding step for forming grooves is performed, and then the tops of the ridges between the plurality of grinding grooves formed in this step are ground to a grain size of 100 to 400 (JIS R6).
001 or JIS R 6010) is subjected to a second grinding step of grinding the grinding sheet to such an extent that the grinding grooves formed in the first grinding step are not completely erased, with the grinding sheet fixed thereon,
Thereafter, the fluff on the top is removed by using a metal brush or a buff or both to form a polished surface in which the penetration of paint is suppressed, and the fluff is formed by leaving fluff on the inner part of the grinding groove. A method for manufacturing wood / thermoplastic composites for painting patterns. 4. A large number of wood-like grinding using a grinding sheet in which abrasive grains having a grain size of 24 to 60 (JIS R 6001 or JIS R 6010) are fixed on the surface of a molded article of a wood / thermoplastic resin composite material. A first grinding step for forming grooves is performed, and then the tops of the ridges between the plurality of grinding grooves formed in this step are ground to a grain size of 100 to 400 (JIS R6).
001 or JIS R 6010) is subjected to a second grinding step of grinding the grinding sheet to such an extent that the grinding grooves formed in the first grinding step are not completely erased, with the grinding sheet fixed thereon,
Thereafter, using a metal brush or buff or both to remove the fuzz at the top to form a polished surface where paint penetration is suppressed, leaving fuzz at the back of the grinding groove, and then painting. A method for forming a grain pattern of a wood / thermoplastic resin composite material comprising