JP3328047B2 - Wood-like molded article and method for producing wood-like molded article - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the manufacture of various molded products such as peripheral boards, skirting boards, rain gutters, flooring materials, wall materials, furniture and the like, and interior parts of vehicles. More particularly, the present invention relates to a method for producing a molded article having a woody appearance.

[0002]

2. Description of the Related Art In recent years, attempts have been made to impart surface characteristics close to those of natural wood to synthetic resin moldings to make the surfaces of various furniture and daily necessities, as well as interior parts of vehicles, etc. natural wood-like. Is being done.

[0003] In order to obtain such a woody resin molded article similar to natural wood, it is colored in a color tone similar to wood, and in order to give a woody taste, it is necessary to form a synthetic resin molded article. When forming a coating film or the like, a required amount of wood flour and a pigment corresponding to a desired color tone are added to a forming resin material to obtain a resin molded product having a color tone and texture close to the target natural wood.

[0004]

By the way, as the wood powder to be added to the resin material for forming the wood-like molded article as described above, wood is generally obtained by directly pulverizing wood into fine powder. .

[0005] However, the wood flour obtained in this way has poor grinding efficiency, whether it is obtained by a dry pulverizer or a wet pulverizer. There was a problem that a large amount of wood flour having a large particle size remained in the flour. In addition, this wood flour does not form a grain shape, and most of it is fibrous, and even if the particle size measured on the short diameter side is several microns, the long diameter side is long in a cilia shape. When used, the wood flours are often entangled with each other to create an agglomerated state, which has the disadvantage that they are not uniformly dispersed in the resin material. Further, since the particle size of the pulverized wood powder is extremely varied, a molded resin molded product is liable to cause molding distortion and the like, and has a disadvantage that the mechanical strength is partially different.

[0006] Therefore, as wood powder added to the formed resin material due to such inconvenience, wood powder obtained by directly pulverizing wood into fine powder has limitations in terms of formulation, color, and quality control. It is.

[0007] In the above-mentioned wood flour, decomposition products such as lignin and wood acid gas are generated in the molding machine due to decomposition of the wood flour during resin molding. There is a problem in that the moldability of the resin is impaired. Therefore, it is common to perform a chemical treatment (neutralization treatment) with, for example, ammonia or urea.

However, if such a chemical treatment is performed, the decomposition of wood powder during resin molding cannot be reliably prevented unless the chemical treatment process is sufficiently controlled, and therefore, the production control (processing process control) is required. ) Must be carried out strictly, which is a major factor in raising production costs. In addition, wastewater used for treatment has a bad effect on the environment, so it is necessary to carry out sufficient treatment, resulting in more and more production There is a problem that the cost is increased.

The applicant of the present invention has proposed that wood flour (cellulose-based fine powder) obtained by such a treatment different from conventional wood flour.
Was developed, and the inconvenience of the conventional wood-like molded article was solved by using this. A wood-like board and a wood-like molded article having an appearance and properties closer to those of a natural tree were proposed. (Japanese Patent Application No. 5-45544) This wood-like board material is subjected to a grinding treatment, and fine cellulose particles having a white inorganic pigment supported on the surface thereof are mixed with a resin, and the mixture is extruded or injection-molded. It is formed in a plate shape. In addition, the wood-like molded product is subjected to a grinding treatment, a cellulose-based fine powder having a white inorganic pigment supported on the surface is mixed with the resin, and the mixture is formed into a plate by extrusion or injection molding. The surface to be coated of the plate-like molded body is subjected to a grinding treatment, and a paint is applied to the surface to be ground.

[0010] However, these wood-like board materials and wood-like molded products have a sufficiently natural woody appearance, but in order to obtain them, cellulose fine particles and resin are directly transferred to a molding machine. Injection does not sufficiently mix the cellulose-based fine particles and the resin, and there is a manufacturing problem that the resulting plate material or molded product has uneven molding. Because of the necessity of painting, there remains a problem to be improved such that the manufacturing process becomes complicated and the manufacturing cost increases.

The present invention has been made in view of the above circumstances, and has as its object the purpose of having a pattern that is very close to the grain of a natural tree on the surface, and the texture, such as touch, being very close to that of a natural tree. A wood-like molded article and a method for producing such a wood-like molded article that can produce such a wooden-like molded article and that can reduce manufacturing costs by eliminating inconveniences in production. Is to do.

[0012]

According to a first aspect of the present invention, there is provided a dough material pellet obtained by mixing a resin and a first colored pigment to form a pellet, and a white pigment which is subjected to a grinding treatment and supported on the surface. The cellulose-based fine particles and the resin are mixed with a wood-like forming material pellet obtained by mixing and pelletizing a second colored pigment having a composition different from the colored pigment of the first composition, and the pellet mixture is obtained. An extruded wood-like molded product, wherein the inside and the surface layer of the wood-like molded product are:
The colored portion of the second colored pigment is unevenly scattered in a streak shape, and a part of the colored portion is concealed by the white pigment of the cellulose-based fine particles in a surface layer portion of the woody molded article. Is a means for solving the above problem. Claim 2
The described invention is a method for producing a wood-like molded product according to claim 1, wherein the dough material pellets and the wood-like forming material pellets are mixed, and the pellet mixture is extruded. A vent-type extruder having a hopper and a vent hole, wherein the vent hole is located between the hopper and the tip of the extruder, wherein the dough material pellet and the wood-like material pellet are placed in the hopper of the vent-type extruder. And the other pellet is supplied to the vent hole, and the pellet supplied from the hopper is extruded forward while being heated and melted in a vent type extruder, and the pellet supplied from the vent hole is vented. While being heated and melted in the extruder, the melt was supplied from the hopper and mixed with the melt extruded forward while being heated and melted. Extruding Te to be characterized were the solutions of the problems.

[0013]

According to the wood-like molded product of the present invention, the wood-like molding
In the interior and surface layer of the article, the second colored pigment
The colored portion due to unevenly scattered streaks,
Part of the part is the surface layer of the wood-like molded product,
Hidden by white pigment supported on fine cellulose powder
The colored part on the surface of the molded product is colored or thick.
Is more uneven and the natural wood pattern
It has a coloration that is very close to that of
A molded article can be provided. And this woody
The shaped article is made of the dough material pellet and the wood-like forming material
Since it is obtained by extrusion molding
For example, around houses, skirting boards, flooring materials, wall materials, furniture, etc.
Applied to the production of various decorative panels and interior materials for vehicles
Low production because it can be obtained by the same molding method as resin
Consists of natural wood, despite being obtained at cost
Almost the same appearance as the one obtained. In addition, the woody material
The shape is ground and has white pigment on the surface.
Is mixed with fine cellulose particles
Cutting and nailing are also possible enough, so almost the same as wood
Cosmetic materials for houses, etc.
Is extremely easy to install on site, etc.
It will be excellent. In addition, according to the method for producing a wood-like molded article, the cellulose-based fine particles are mixed in advance with a resin or the like, and the wood-like forming material and the resin are mixed in advance and pelletized. It is no longer necessary to feed into the extruder and mix in the extruder, so that the dispersion of the cellulose-based fine particles in the resin is improved.

[0014] Further, one of the pellets of the cloth material pellets having the first colored pigment and the wood-like forming material pellets having the second colored pigment different in composition from the first colored pigment is placed in a hopper. The other pellet is extruded with a hopper
Supplied to the vent hole located between the distal end of the machine, or hopper
The pellets supplied from the furnace are melted by heating in a vented extruder.
While pushing it forward, and the pellet supplied from the vent hole.
While heating and melting the heater in a vented extruder,
And is extruded forward while being heated and melted.
Since it is mixed with the melt and extruded, the melting time of the pellets charged to the vent hole side is shorter than the pellets charged to the hopper side, thereby causing a temperature difference between the two pellet melts, Since the time for mixing them is also shorter than when both are put into the hopper at the same time, the resulting extruded product also has uneven mixing between the pellets. Therefore, even between the first colored pigment and the second colored pigment contained in these pellets, the degree of mixing is uneven, and these flow unevenly. In addition to the formation of colored portions of high and low density, many of these colored portions are not continuous stripes but intermittently independent.

In addition, since the cellulose-based fine particles in the wood-like forming material pellets carry a white pigment on the surface thereof, in the obtained molded article, the white pigment comes closer to the surface than the colored pigment, and The color of the colored pigment is concealed, whereby the colored portion on the surface of the molded article formed by the colored pigment becomes more non-uniform in its color and thickness, and the resulting molded article is closer to a natural grain pattern. It has a colored portion. In addition, since the aggregate is made of fine cellulose particles having been subjected to attrition treatment and having a white pigment supported on the surface, the absorption and suction of the resin by the fine particles are extremely reduced, and molding distortion hardly occurs.

[0016] Further, since the cellulose-based fine particles in the wood-like forming material pellets carry a white pigment having higher heat resistance than wood, the heat-resistant white pigment is more heat-resistant than the cellulose-based fine particles before loading. Therefore, compared to the case of simply blending and mixing cellulose-based fine particles such as wood flour, the heat effect during molding is less, and therefore the color and shape of the molded product caused by the thermal decomposition of the cellulose-based fine particles are reduced. Deterioration such as change is suppressed. In addition, by supporting the white pigment, the surface of the cellulosic fine particles is covered, thereby suppressing the release of lignin and wood acid contained in the fine particles during molding. Molding failure due to the release of water is prevented.

[0017]

Hereinafter, the present invention will be described in detail.

The method for producing a wood-like molded article of the present invention comprises mixing a dough material pellet and a wood-like forming material pellet at a predetermined ratio, and molding the pellet mixture into a desired shape by extrusion. Is a plate-shaped molded product such as a perimeter of a house, skirting board, flooring material, wall material, various decorative boards such as furniture, vehicle interior material, etc., or a tubular or nearly half-shaped product such as a rain gutter or a brush shaft. This is a method for producing various molded products such as a cylindrical molded product and a pencil shaft.

As the material pellets, pellets obtained by mixing a resin, a first colored pigment, and various additives added as necessary, for example, a heat stabilizer and the like are used.

As the resin used as a component of the pellet, vinyl chloride resin, polyethylene resin, polypropylene resin, phenol resin, ABS resin and the like are used, and among them, vinyl chloride resin is more preferably used. As the first colored pigment, basically, cadmium yellow and iron oxide, yellow, red, such as carbon black, consisting of inorganic pigments of three colors of red, black, the color is particularly mixed color of the second colored pigment described below It is used in such a manner as to be brownish in comparison with the compounding, and the amount of addition is about 0.5 to 5% by weight of the whole pellets.

The dough material pellets may be blended with, if necessary, a cellulose-based fine particle which has been subjected to a grinding treatment and has a white pigment supported on the surface, which is blended with a wood-like forming material pellet described later. . In this case, the amount of the cellulosic fine powder to be added is 5-60
% By weight.

A colored pigment is added to the resin in such a composition, and various additives and cellulose-based fine particles are added at an appropriate ratio, if necessary, and then mixed and pelletized to form a dough material. Pellets are obtained. Pelletization is performed by a conventionally known means such as extruding the mixed powder into a string form from a porous circular nozzle and cutting it.

The wood-like forming material pellets are obtained by subjecting cellulose-based fine particles, which have been subjected to attrition treatment to have a white pigment supported on the surface thereof,
The resin, the second colored pigment, and various additives added as required are mixed and pelletized.

The cellulosic fine particles which have been subjected to attrition treatment and have a white pigment carried on the surface thereof are raw materials for various plant cell bodies such as coarsely ground wood, coarsely ground Bacas, and coarsely ground rice straw. It is obtained by using a coarsely pulverized material as a starting material, subjecting it to a grinding treatment, and further carrying out a treatment for supporting a white pigment on the finely divided particles. Here, the grinding process means a process having both a grinding process and a polishing process. Even if the grinding process and the polishing process are performed simultaneously, the grinding process is performed after the grinding process is performed. It may be a two-step process. In other words, the grinding treatment referred to here is a grinding treatment for converting a coarsely crushed material into a finely crushed material as described later, and the finely crushed powder particles are entangled in a fiber state, and the surface thereof is covered with cilia. This refers to a process in which a polishing process of polishing the surface so as to reduce the amount of cilia on the surface from the shape of the granular material in the state in which the particles are in a state of being performed is combined.

In order to obtain a coarsely pulverized product as a starting material, the chips and the like are pulverized by mechanical impact crushing to obtain a coarsely pulverized powder having a particle size smaller than 150 mesh, preferably smaller than 120 mesh. Here, for mechanical pulverization, for example, an impeller mill (IMP-250; manufactured by Seishin Enterprise Co., Ltd.)
Is preferably used.

The grinding of the raw material (coarse pulverized material) is preferably performed by, for example, a ball mill shown in FIG. This ball mill is provided with a cooling jacket 2 on the peripheral wall of a mill body 1 which is open to the atmosphere. Cooling water is supplied from a supply pipe 8 into the cooling jacket 2 and discharged from a drain pipe 9 to circulate the cooling water. Thereby, the temperature in the mill body 1 is set to a preset temperature, for example, 80 ° C. or less.

Here, a motor 5 is provided on the top of the mill body 1, and a rotor 4 for stirring the balls 3 in the mill body 1 is provided on the bottom of the motor 5. The rotor 4 is rotated by the drive of the motor 5, and agitates the ball 3 and the material to be ground to bring them into mechanical contact. Further, an outlet 7 which is opened and closed by a valve 6 is provided at a lower portion of the conical shape of the mill body 1.
The material to be ground after the grinding processing can be discharged.

The ball 3 loaded into the mill body 1 of the ball mill is a ceramic ball having an outer diameter of 3 mm to 5 mm,
In particular, it is preferable to use zirconia-based or alumina-based ceramic balls, and it is desirable to avoid using metal balls such as stainless steel and steel. This is because, in the case of balls made of metal such as stainless steel and steel, there is a possibility that ground cellulose powder such as wood powder may bind to the surface of the balls, or may cause deterioration of the ground powder due to heat generated by contact between the metal balls. Also, fragments of metal balls may be generated, and the fragments may be carried on the surface of the pulverized cellulose and may be different from desired fine powder particles.

The dry ball mill may be a closed type or an open-to-atmosphere type. When the closed type ball mill is employed, it is preferable to fill the mill with an inert gas such as nitrogen gas. preferable.

In this ball mill, balls 3
Is adjusted to be in the range of 90 ° C. to 120 ° C. and the room temperature of the mill body 1 is adjusted not to exceed 80 ° C. The drying process is also performed at the same time. Here, regarding the temperature control of the balls 3 to be used, the capacity of the mill body 1, the amount of the balls 3 put into the mill body 1,
This is performed by adjusting the stirring speed, the amount of cooling by the cooling jacket 2 provided on the peripheral surface of the mill body 1, and the like, based on the material and dimensions of the mill and the charging temperature, amount, and moisture content of the charged pulverized material.

The surface temperature of the ball 3 varies depending on the target material.
It is preferable to set the temperature within the range of from 120 ° C to 120 ° C from the viewpoint of grinding efficiency. However, when a long time is required for grinding, the temperature is preferably from 90 ° C to 100 ° C from the viewpoint of preventing explosion.
If there is a risk of explosion during grinding,
It is preferable that the oxygen concentration in the mill body 1 be within 15%, in which case, for example, a method of continuously supplying nitrogen gas into the ball mill can be adopted.

According to the grinding treatment by such a ball mill, the internal temperature of the mill body 1 rises due to frictional heat generated by the rotation of the balls 3, while the cooling water circulated through the cooling jacket 2 causes the mill body 1 By adjusting the internal temperature and the surface temperature of the ball 3 to the above ranges,
The raw material pulverized material is pulverized and dried under appropriate heating conditions at the same time, whereby the particle size is in a desired range,
For example, the water content is adjusted to 100 μm or less, and the water content is adjusted to about 3.0% by weight or less.

According to this processing, the ball 3 comes into contact with the raw material pulverized material charged in a coarse powder state,
The raw material pulverized material that comes into contact with the ball 3 is pulverized into a finely pulverized material, and the surface is polished into fine particles having a surface with very few cilia.

That is, when the raw material pulverized material comes into contact with the surface of the ball 3, it is mechanically crushed and abraded to be pulverized.
Since the polishing is performed and the heating and drying are performed at the same time, the water content is efficiently removed. Further, since the fibers in the pulverized raw material are rapidly cooled when separated from the ball 3, the fibers in the raw material pulverized material are rapidly dried by being repeatedly subjected to heating and cooling. The portion is efficiently ground by the ball 3, and as a result, ground cellulose-based fine particles having an independent particle shape with little cilia on the peripheral surface are obtained.

Then, the cellulose fine powder particles thus obtained are classified, and the particle size in a desired range (for example, 1 to 5) is obtained.
10 μm, 10 to 20 μm, 20 to 50 μm, 50 to 1
00 μm) to obtain cellulose-based fine particles for supporting a white pigment.

The grinding of the raw material pulverized material can be carried out by using, for example, a pulverizer 30 as shown in FIG. 2 instead of the ball mill shown in FIG. This crusher 30
Is based on the principle of stone thinning.
The grinding and polishing processes, that is, the grinding process, are performed by rotating one of the grindstones 31 at a high speed after the raw material pulverized material is put between them with a predetermined gap therebetween. Here, the grindstones 31 are dish-shaped in which the inner surface gradually inclines upward or downward as the inner surface goes toward the center, and they are arranged facing each other so that the center is wide and the peripheral is narrow. Is used. These grindstones 31 have a donut plate shape with a mounting hole 32 formed in the center as shown in FIG. 3, and have a large number of feed grooves 33 formed on the inner surface thereof. The feed groove 33 is for smoothly guiding the workpiece in the radial direction of the grindstone 31 by the centrifugal force generated by the rotation of the grindstone 31.

In order to grind the raw material pulverized material by such a pulverizer 30, the raw material pulverized material is put between the central portions of the two grindstones 31, and then one of the grindstones 31 is moved at a high speed. Rotate. Then, the raw material pulverized material is subjected to centrifugal force, impact force, shearing force and the like between the two grindstones 31 and 31 and is gradually pulverized.
Is moved to the radially outer peripheral side along ..., and in the process, it is pulverized by receiving an impact force and a shearing force, and its peripheral surface (surface) is polished. It becomes a milled cellulose fine powder having an independent particle shape with little cilia.

The cellulose fine particles thus obtained are classified and adjusted to a desired particle size in the same manner as in the case of using a ball mill.
The cellulose-based fine powder of the present invention for supporting a white pigment is obtained. Here, as the white pigment to be supported, titanium oxide, lithopone, white carbon, calcium carbonate and the like can be used. In particular, titanium oxide is thermally and chemically stable as described later, and has a coloring power. In addition, since it has excellent hiding power, a sufficient whiteness can be imparted to the obtained wood-like molded product, which is preferable. The particle size of the white inorganic pigment is adjusted to be sufficiently smaller than the cellulosic fine particles, and specifically, 0.1.
Those having a size of about μm are preferable.

As a method for supporting the white pigment on the cellulose-based fine particles (milled fine particles), when the cellulose-based fine particles are obtained by a ball mill shown in FIG. And a white pigment are mixed, and the resulting mixed particles are dispersed in a gas phase while applying mechanical thermal energy mainly to impact force to the particles, and the cellulose-based fine particles are used as base particles, and the base particles are used as base particles. A method of supporting white pigment particles on the peripheral surface of the substrate. That is, this method is a method utilizing the fact that white pigment particles are harder than cellulosic fine particles, and such a difference in hardness causes the white pigment particles to sink into the surface of the cellulosic fine particles, or to eat. It can be carried in the state of being inserted.

As another supporting method, particularly when cellulose fine powder particles are obtained using the pulverizer 30 shown in FIG. 2, mixed particles of the cellulose fine powder and white pigment are shown in FIG. It is preferable that white pigment particles are carried on the peripheral surface of the cellulose-based fine particles by charging the mixture into such a ball mill and performing the grinding treatment again. This is because, in the grinding process using a ball mill, as described above, frictional heat is generated in the process, and as a result, the drying process is performed at the same time.

By carrying out such a supporting treatment, as shown in FIG. 4, the white pigment particles 10 are supported in a biting state on the peripheral surface of the cellulosic fine powder particles 11, whereby the white pigment particles 10 are subjected to attrition treatment to give a white color. Cellulose-based fine particles having the pigment carried on the surface are obtained. The pigment-carrying cellulosic fine particles obtained in this manner have a color tone substantially the same as the color tone of the white inorganic pigment, and no agglomeration is observed in both the manufacturing process and the storage process of the supported fine particles. Was.

The amount of the white pigment to be supported is as follows:
The upper limit is the amount that overlaps the peripheral surface of the cellulosic fine particles serving as the base particles and covers the peripheral surface. The lower limit is appropriately determined according to the desired hue of the wood-like molded article to be produced.

As the resin used as the component of the wood-like pellet, the resin used in the above-mentioned fabric material pellets, that is, a vinyl chloride resin, a polyethylene resin, a polypropylene resin or the like is used, and among them, the vinyl chloride resin is preferably used.
When selecting the resin, it is naturally preferable to use the same type of resin as the resin used for the base material pellets, because molding conditions such as a melting temperature can be easily determined.

As the second colored pigment, similarly to the first colored material used for the base material pellets, there are basically three colors of inorganic materials such as cadmium yellow, iron oxide, and carbon black. A pigment is used which is mixed so that the mixed color becomes yellowish as compared with the above-mentioned first colored pigment, and the amount of addition is 0.5 to 5% by weight of the whole pellet. Degree.

The compounding amount in the whole woody pellet of the supported cellulose fine powder is 5 to 60% by weight of the whole pellet. Further, pelletization is performed by a conventionally known means as in the case of the dough material pellets. Since the cellulose-based fine particles and the resin or the like are previously mixed and pelletized as described above, they are not directly mixed in the molding machine during molding, and therefore, the dispersion of the cellulose-based fine particles in the resin is prevented. Become good.

In the present invention, such a dough material pellet and a wood-like pellet are supplied to a vent-type extruder as shown in FIG. 5 to be formed. In FIG.
Is a vent type extruder (hereinafter, abbreviated as an extruder),
The extruder 40 includes a cylindrical cylinder 41, a screw 42 provided therein, a hopper (first hopper) 43 provided at a rear end of the cylinder 41, and a cylinder 4.
1 is a known single-screw extruder including a vent hole 44 formed at the front end side of the central portion of the first and a die 45 provided at the front end of the cylinder 41 to impart a desired shape to the pellet melt.

A second hopper 46 is connected to the extruder 40 so as to communicate with a vent hole 44. One of the dough material pellet or the wood-like forming material pellet is connected to the second hopper 46. Supplied and stored. Further, pellets different from the pellets stored in the second hopper 45 are supplied to and stored in the first hopper 43. In addition,
The first and second hoppers 43 and 46 respectively feed the stored pellets by a predetermined amount into the screw 4 in the cylinder 41.
The pellets are connected to a hopper loader (not shown), whereby pellets are automatically supplied.

The screw 42 has a deep groove portion 42a formed at a position corresponding to the position where the vent hole 44 is formed, whereby the pellets from the second hopper 46 are allowed to pass through the deep groove portion 42a. While being injected from one hopper 43 and being heated and melted in the cylinder 41, it is injected and mixed into the pellet melt conveyed by the screw 42 without any trouble. Here, the molding temperature of the extruder 40, that is, the heating and melting temperature of the pellets varies depending on the type of resin forming the pellets, but is, for example, about 180 to 210 ° C. when vinyl chloride is used.

The mixing ratio between the dough material pellet and the wood-like formed pellet is appropriately determined based on the hue of the obtained molded article and the ratio of the colored pigment in each pellet. Forming material pellets = 90: 1
0 to 99: 1 (weight ratio). In determining which hopper to supply these pellets to, respectively, based on the mixing ratio of these pellets, the higher mixing ratio is assigned to the first hopper 43 and the lower mixing ratio is assigned to the second hopper 4.
5 is preferred. This is because, if the higher proportion is supplied to the first hopper 43 so as to be sufficiently melted, the occurrence of molding failure can be more prevented as compared with the case where the reverse is performed.

When molding is performed by such an extruder 40, the pellets supplied from the first hopper 43 are put into a cylinder 41, and are extruded forward by a screw 42 while being heated and melted therein. Further, the pellets supplied from the second hopper 46 are introduced into the cylinder 41 through the vent hole 44 and supplied to the deep groove 42a of the screw 42. Then, the volume of the melt from the first hopper 43 becomes larger in the cylinder 41 of the deep groove portion 42a than before the deep groove portion 42a.
a, a sufficient gap is formed, whereby the pellets from the second hopper 46 are supplied to the gap without being subjected to a large stress by the pellet melt, and are mixed into the melt. Become. The pellets from the second hopper 46 are heated and melted in the cylinder 41 while the first hopper 4 is
3 and extruded with the pellet melt. Then, the dough material pellets and the wood-like forming material pellets are melted, mixed, and extruded from the die 45 in this manner, to become a wood-like molded product formed into a desired shape.

According to such a production method, the base material pellets and the wood-like forming material pellets melt and flow in the molding direction, whereby each resin, the supported cellulose fine powder, the first colored pigment, the second colored pigment, The colored pigments are mixed with each other. However, since one of the pellets is supplied from the vent hole 44 near the die 45 to make a difference in the melting time of the two pellets and thereby to make a difference in the temperature between the pellets, these pellets are mixed sufficiently uniformly. However, the first colored pigment and the second colored pigment in both the pellets are not mixed sufficiently uniformly, so that the resulting molded article has its inner and surface layers as shown in FIG. The colored portions 20... Of colored pigments are scattered non-uniformly at the portions, and on the surface of the molded product, for example, when formed into a plate, as shown in FIG. The colored portions 20 which are independent and have uneven shades and uneven streaks are formed.

In particular, in the surface layer portion of the molded article, when the cellulose-based fine particles carrying the white pigment in the wood-like forming material pellets come on the colored portion 20, the color of the colored portion 20 is changed by the white pigment. Is concealed, the density of the colored portion 20 (streak pattern) visible on the surface shown in FIG. 7 becomes more uneven, whereby the colored portion 20 becomes closer to a natural grain pattern. .

In particular, when titanium oxide is used as a white pigment, the cellulose-based fine particles carry thermally and chemically stable titanium oxide. Without the application, the decomposition of cellulose fine powder particles during molding can be suppressed.

In the embodiment, a single-screw extruder is used. However, a twin-screw extruder may be used. Any of the two-way directional can be used.

[0055]

As described above, the invention according to claim 1 is described above.
According to the cellulosic material in the wood-like forming material pellets
Fine particles carry a white pigment with higher heat resistance on the surface than wood.
Of the cellulose-based fine powder before loading.
In all, the heat resistance has been improved, and
When molding compared to the case where shaping is performed by blending lurose fine particles
Little thermal effect, thus thermal decomposition of cellulosic fine particles
Deterioration of molded products such as color and shape changes due to
It is. In addition, the inside of the woody molded article and the surface layer
The colored portion of the second colored pigment is unevenly streaked.
Are scattered around. And a part of the coloring section is made of the wooden material.
In the surface layer of the molded article,
Because it is hidden by the carried white pigment,
Colored parts on the surface of molded products are more uneven in color and thickness
It is very close to the natural wood pattern
Part. Further, the wood-like molded article is polished.
Cellulose that has been crushed and carries a white pigment on the surface
Cutting with a saw or nailing
Is also possible, so it is almost the same as wood.
Because it can be handled, it was used as a cosmetic material for houses, etc.
Extremely excellent workability such as installation on site even in cases
Becomes According to the second aspect of the invention, the cellulosic fine particles are mixed in advance with a resin or the like, and the wood-like forming material and the resin or the like are previously mixed and pelletized. Since the pellets are supplied to the extruder and molded, the cellulose-based fine particles and the resin are not separately supplied to the extruder and mixed in the extruder during molding. It is possible to improve the dispersion of the cellulose-based fine particles to prevent poor molding. In addition, one of the dough material pellet and the wood-like forming material pellet is placed in a hopper, and the other pellet is placed between the hopper and the tip of the extruder.
It was supplied to the vent hole, which is supplied from a hopper
The pellets are heated and melted in a vented extruder while moving forward.
Extrude and vent the pellet supplied from the vent hole
Supplied from the hopper while heating and melting in the extruder.
Mixed with the melt extruded forward while heating and melting.
Since they are extruded together , the melting time of the pellets placed on the vent hole side is shorter than the pellets placed on the hopper side, which causes a temperature difference between the two pellet melts, The time when these are mixed is also shorter than when both are put into the hopper at the same time. Therefore, due to uneven mixing between the pellets, of course, uneven mixing occurs between the first colored pigment and the second colored pigment contained in these pellets, and these colored pigments flow unevenly. In addition to forming unevenly colored portions in the molded article, many of these colored portions can be discontinuous and independent, close to a natural grain pattern, rather than continuous streaks.

Moreover, since the cellulose-based fine particles in the wood-like forming material pellets carry the white pigment on the surface thereof, the white pigment comes to the surface side of the colored pigment in the obtained molded article, and The color of the colored pigment is concealed, whereby the colored portion on the surface of the molded article formed by the colored pigment becomes more non-uniform in its color and thickness, and the resulting molded article is closer to a natural grain pattern. It has a colored portion. Therefore, the production method of the present invention can obtain a molded product having a surface very close to that of a natural tree without performing painting or grinding treatment. When applied to the manufacture of various decorative panels in wall materials and furniture, interior materials for vehicles, etc., it is made of natural wood, despite being obtained at a low production cost because it can be obtained by the same molding method as resin. The appearance is almost the same as that of the resin molded product, and a product having a much higher quality can be obtained as compared with a resin molded product which has been conventionally used as a substitute product and has a wood grain pattern printed thereon.

When fibrous wood powder (cellulose-based fine particles) which has not been subjected to conventional grinding treatment is incorporated in a resin as an aggregate, a treating agent for neutralizing the wood powder with alkali is used. Yellowing due to the effect of the above, furthermore it becomes a brown plate material, and molding distortion occurs due to sucking of resin, etc., but in the present invention, cellulose fine powder particles which only carry a white pigment and are not subjected to alkali treatment Does not cause discoloration, and since the cellulosic fine particles are granular rather than fibrous, they have very little expansion and contraction. Therefore, the present invention using this has extremely excellent dimensional stability upon molding. Production method.

Further, since the cellulose-based fine particles having been subjected to attrition treatment and having a pigment carried on the surface are used as aggregates, the resin is hardly adsorbed and sucked by the fine particles, so that molding distortion is hardly caused. Disappears.

In the obtained wood-like molded product,
In particular, when titanium oxide is used as a white pigment, the heat resistance is improved as compared to before loading since the cellulose-based fine particles carry titanium oxide, and therefore, only the cellulose-based fine particles such as wood powder are blended. As compared with the case of molding by heat, the heat influence during molding is small, so that the deterioration such as color and shape change is suppressed. In addition, by supporting the white pigment, the surface of the cellulose-based fine particles is covered, thereby suppressing the release of lignin and wood acid contained in the fine particles due to thermal decomposition during molding. According to the production method of the present invention, it is possible to prevent molding defects caused by the release of the lignin and wood acid. In addition, the surface area of the cellulosic fine particles is larger than that of conventional wood flour due to the support of the pigment, and therefore, the degree of adhesion between the fine particles and the resin is increased in the obtained molded article.

Further, since the obtained wood-like molded article contains cellulosic fine particles, it can be cut or nailed sufficiently with a saw, and can be handled almost in the same manner as wood, so that it can be used in houses and the like. Even when it is used as a cosmetic material, it is extremely excellent in workability such as installation on site.

[Brief description of the drawings]

FIG. 1 is a fragmentary front view of an open type ball mill.

FIG. 2 is a schematic configuration diagram showing an example of a crusher used for a grinding process.

FIG. 3 is a plan view showing an example of a grindstone of the crusher shown in FIG. 2;

FIG. 4 is a cross-sectional view showing a state in which a white inorganic pigment of cellulosic fine powder used in the present invention is supported.

FIG. 5 is a side sectional view showing an example of an extruder used in the present invention.

FIG. 6 is an enlarged side sectional view of the obtained molded product.

FIG. 7 is a perspective view showing a surface state of the obtained molded article.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mill body 3 Ball 10 White pigment particle 11 Cellulose fine powder 20 Coloring part 30 Crusher 40 Vent extruder 43 Hopper 44 Vent hole

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B29C 47/00-47/96

Claims (2)

(57) [Claims] 1. A dough material pellet obtained by mixing a resin and a first colored pigment to form a pellet, a cellulose-based fine particle on which a white pigment is supported by a grinding treatment and a resin, the resin, A wood-like shaped article obtained by mixing a wood-like forming material pellet obtained by mixing and mixing a second colored pigment having a different formulation from the colored pigment of one formulation and being pelletized, and extruding the pellet mixture, Inside and in the surface layer of the wood-like molded article, the colored portion of the second colored pigment is unevenly scattered in a streak shape, and a part of the colored portion is the cellulose in the surface layer of the wood-like molded article. A wood-like molded product characterized by being concealed by a white pigment of fine system particles. 2. The method for producing a wood-like molded product according to claim 1, wherein the dough material pellets and the wood-like forming material pellets are mixed, and the pellet mixture is extruded. A vent-type extruder having a hopper and a vent hole, wherein the vent hole is located between the hopper and the tip of the extruder, wherein the dough material pellet and the wood-like material pellet are provided in the hopper of the vent-type extruder. And the other pellet is supplied to the vent hole, and the pellet supplied from the hopper is extruded forward while being heated and melted in a vent type extruder, and the pellet supplied from the vent hole is vented. While heating and melting in the extruder,
A method for producing a wood-like molded product, comprising mixing with a molten material supplied from the hopper and extruded forward while being heated and melted, causing unevenness in mixing between pellets, and extruding.