Plastic article or earthenware shaping or treating: apparatus – With separate and distinct upstream agitating or kneading means – With separate and distinct gas withdrawal chamber
Reexamination Certificate
2000-07-18
2004-04-27
Davis, Robert (Department: 1722)
Plastic article or earthenware shaping or treating: apparatus
With separate and distinct upstream agitating or kneading means
With separate and distinct gas withdrawal chamber
C425S208000, C366S075000, C366S076600, C366S076930, C366S089000
Reexamination Certificate
active
06726464
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a resin molding device and a resin molding method, and particularly to the molding technology for presenting a clear pattern in plastics containing a pigment and also preventing a remarkable lowering of strength.
BACKGROUND OF THE INVENTION
1. Prior Art
The technology of manufacturing a molding presenting colors and patterns by mixing a pigment in resin has been known for long. Typical of the above is the technology of mixing powder (wood flour) of natural wood in resin to manufacture a molding, the so-called wood plastic, and various technology has been proposed heretofore. Among them, the technology of “cellulosic granular powder, a wood-like molding and a wood-like product” disclosed in PCT JP94/00351 (International Laid-Open No.: WO94/20280) will now be described in brief.
The pulverized powder obtained by grinding cellulose material as raw material is ground to obtain granular powder increased in bulk specific gravity, a surface grain which has a diameter smaller than that of the granular powder and is harder than the powder is fixed to the outer peripheral surface of the granular powder to obtain a fixed grain, resin and a pigment are mixed with the fixed grain and molten, and after that, or simultaneously with melting, the mixture is formed into a desired shape by extrusion molding or injection molding. According to this technology, it is possible to provide a method of manufacturing a wood-like product and a wood-like product which has a pattern very close to the grain of natural wood and also has feeling such as the touch or the like close to the natural wood.
The technique about the device for extrusion molding is disclosed in prior art such as U.S. Pat. No. 3,966,857, U.S. Pat. No. 3,388,196 and JP-A-62198435.
2. Disadvantage of the Prior Art
It is, however, true that not only in the above technology, giving of coloring to a resin molding is hard to be incompatible with keeping the strength of the resin molding. That is, it is preferable to incompletely mix resin in order to give coloring to the resin molding, but if done so, the strength of the molding is lowered. On the contrary, if mixing is performed completely, the strength of the molding can be increased, but the coloring fades.
Objects of the Invention
A problem to be solved by the invention is to provide the technology by which giving of coloring to a resin molding is made compatible with preventing a remarkable lowering of strength of the resin molding.
It is an object of the invention to provide a method of manufacturing a molding by which clear colors and patterns can be presented without a remarkable lowering of strength.
It is another object of the invention to provide a mixing device for extrusion molding by which clear colors and patterns can be presented without a remarkable lowering of strength.
Further in detail, listed are the respective objects of the invention.
One object of the invention is to provide a manufacturing method by which clear colors and patterns can be presented without a remarkable lowering of strength and to provide a method of manufacturing a molding having the woody feel.
Another object of the invention is to provide a manufacturing method y which a molding having a clear pattern can be manufactured.
Another object of the invention is to provide a mixing device for extrusion molding by which energy required for manufacture can be held down, and by which a molding having a clear pattern can be manufactured.
Another object of the invention is to provide a mixing device for extrusion molding by which the existing equipment can be utilized to the maximum.
The present invention is intended for accomplishing the described objects.
In one embodiment, the invention is a molding manufacturing method using a mixing device
10
for extrusion molding comprising a main cylinder
11
positioned on this side of a metal mold for shaping a molding and a main screw
12
rotated in the main cylinder
11
for mixing resin material
20
and delivering the same to the metal mold, wherein immediately before delivery to the metal mold, an outer resin material
21
positioned on the inner wall side of the main cylinder
11
is put in the molten state, and an inner resin material
22
positioned on the main screw
12
side is controlled to be from the softening temperature to the melting temperature both inclusive. Moreover, cellulose material is mixed with the outer resin material
21
. Furthermore, cellulose material mixed with the outer resin material
21
is fixed grains formed by fixing a surface grain which has a diameter smaller than that of the pulverized powder obtained by pulverizing the cellulose material and is harder than the powder to the outer peripheral surface of the pulverized powder.
The “main”of the “main cylinder
11
” means any one of cylinders in multilayer molding, for example, and the only one cylinder in monolayer molding. The “main ” of the “main screw
12
” means a screw incorporated in the main cylinder, and in the case of using plural screws in the main cylinder, it means all of the screws.
As concrete means for “immediately before delivery to the metal mold, putting an outer resin material
21
positioned on the inner wall side or the main cylinder
11
in the molten state, and controlling an inner resin material
22
positioned on the main screw
12
side to be from the softening temperature to the melting temperature both inclusive”, cited are means for controlling the temperature of a heater for heating the main cylinder and the main screw, means for making the particle size of resin material positioned on the main cylinder inner wall side smaller than that of resin material positioned on the main screw side, and the like.
Here, “resin material” means material used at the time of making a resin molding such as polyvinyl chloride which is thermoplastic resin or the like. Though only the resin as base material will be resin material, if wood flour (cellulose material) is contained in resin, it becomes resin material used in the so-called wood plastic molding.
As for the resin material used in wood plastic molding, it is frequent to use the material obtained by mixing wood flour with resin and pelletizing the same in addition Lo the powdered material obtained by mixing wood flour with powder resin. Further, frequently in order to produce a pattern of the grain of wood, “resin material” is added to wood flour and resin to obtain a mixture of a pigment. In that case, sometimes one kind of a pigment will be sufficient, and sometimes plural kinds of pigments are used. In the case of using plural kinds of pigments, “resin material” can be made by preparing plural kinds of pellets with different pigments and mixing the same.
The cellulose material used in manufacturing fixed grains is ordinarily natural wood, or sawdust, but rice straw and bagasse may be used.
As a method of forming fixed grains by “fixing surface grains which have a diameter smaller than that of the granular powder and are harder than the powder to the surface of pulverized powder”, cited are grinding using a ball mill, long-time high-speed mixing using a mixer, and so on. By these methods, fuzz of fibers of the cellulose material is decreased. Processing for removing fuzz of fibers of the cellulose material may be performed separately from fixing of surface grains.
The “surface grains”are metal, metal compounds such as titanium oxide, ferrite, aluminum, nickel, silver, calcium carbonate and the like, and nonmetal such as ceramic or the like.
The percentage of fixed grains mixed with resin to the whole is usually set not more than 30 wt %. The reason is that sometimes the fluidity at the time of melting the material to be molded becomes worse to interfere with molding.
The material formed by mixing fixed grains with resin which is resin material may be pulverulent or be previously molded to be pelletized. In order to bring out a pattern of the grain of wood, sometimes one kind of a pigment will be sufficient, but frequently plural kinds of pigments are used. In
Hasumi Konomi
Ishikawa Masatoshi
Kato Masami
Davis Robert
Del Sole Joseph S.
Misawa Homes Co.
Wolf Greenfield & Sacks P.C.
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