Plastic and nonmetallic article shaping or treating: processes – Random variegated coloring during molding
Reexamination Certificate
2001-02-26
2003-12-09
Ortiz, Angela (Department: 1732)
Plastic and nonmetallic article shaping or treating: processes
Random variegated coloring during molding
C264S245000, C264S255000, C264S328180, C264S328120
Reexamination Certificate
active
06660196
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a grained injection molded product, a method and a device for producing a grained injection molded product.
BACKGROUND TECHNOLOGY
A method for the preparation of a grained injection molded product, i.e., an injection molded product with a grain-like pattern on the surface of the product from a synthetic resin is disclosed, for example, in Japanese Patent Application Laid-Open No. 8-276,464. This disclosed method is adaptable to the large-scale preparation of injection molded products from synthetic resin, which are provided with a grain-like pattern resembling a grain of a natural wood product.
This disclosed method can provide an injection molded product with a grain-like pattern on its surface; however, it cannot form a pattern of high quality such as a fine grain-like pattern.
Therefore, the present invention has the primary object to provide a grained injection molded product with a fine grain-like pattern remarkably resembling a wooden product with a natural grain pattern.
The present invention has another object to provide a method for the preparation of an injection molded product with such a grain-like pattern resembling a grain of a natural wooden product.
The present invention has a further object to provide a device for use in the preparation of an injection molded product with a grain-like pattern resembling a grain of a natural wooden product.
DISCLOSURE OF THE INVENTION
In order to achieve the first object as described above, the present invention provides a grained injection molded product on at least a surface of the injection molded product from a molten resin being composed of a first material and a second material having a color different from the color of the first material and combined in an incompletely mixed state, that is, in a substantially separately mixed state such that the first material and the second material are not completely mixed and separately combined so as to visibly distinguish the colors of the two materials from each other, the injection-molded product prepared by feeding the molten resin as in the form of divided streams into a cavity, elongating the divided streams into a desired shape of a product, and allowing the divided streams to solidify with traces of the divided streams in the form of a grain-like pattern retained on the surface of the product; wherein each of the divided streams is allowed to solidify into a solidification layer comprising a first solidification layer section and a second solidification layer section, the first solidification layer section being composed substantially of the first material and extending in a direction of elongation of the divided stream on the inside thereof and the second solidification layer section being composed substantially of the second material and extending in a direction of elongation of the divided stream on both sides thereof.
In order to further achieve the primary object, the present invention provides an injection molded product with a grain-like pattern on at least a surface of the injection molded product, prepared by feeding a molten resin composed of a mixture of a first material and a second material having a color different from that of the first material, combined in a substantially separately mixed manner, in the form of plural divided streams to a cavity, elongating the plural divided streams into the product, and allowing the plural divided streams to solidify with traces of the divided streams in the form of a grain-like pattern retained on at least the surface of the product; wherein the molten resin is allowed to solidify into a solidification layer with the trace of the divided stream retained thereon and a reinforcement member is disposed inside the solidification layer for supporting for the solidification layer; and wherein the solidification layer of each divided stream comprises a first solidification layer section and a second solidification layer section, the first solidification layer section being composed substantially of the first material and extending in a direction of elongation of the divided stream on the inside thereof and the second solidification layer section being composed substantially of the second material and extending in a direction of elongation of the divided stream on both sides thereof.
In order to achieve the second object, the present invention provides a method for the preparation of an injection molded product with a grain-like pattern, which comprises feeding a molten resin composed of a first material and a second material having a color different from that of the first material to a cavity resin feed end of a cavity, the molten resin being a mixture of the first and second materials in a substantially separately mixed manner; and feeding the molten resin into the cavity from the cavity resin feed end thereof as in the form of a plurality of divided streams.
In order to further achieve the second object, the present invention provides a method for the preparation of an injection molded product with a grain-like pattern, which comprises feeding a molten resin to a cavity resin feed end of a cavity with a reinforcement member set at a site corresponding to the inside of the injection molded product, the molten resin being composed of a first material and a second material having a color different from that of the second material and combined in a substantially separate manner; and feeding the molten resin from the cavity resin feed end thereof into a space of the cavity between the reinforcement member and a wall surface of the cavity in the form of a plurality of divided streams.
In order to achieve the third object, the present invention provides a device for use in the preparation of an injection molded product with a grain-like pattern, wherein a gate is disposed at the cavity resin feed end of the cavity; and the gate is arranged so as to flow the molten resin into the cavity in the form of plural divided streams in a parallel arrangement.
In order to further achieve the third object, the present invention provides a device for use in the preparation of an injection molded product with a grain-like pattern, wherein the reinforcement member is set at a site of the cavity corresponding to the inside of the injection molded product; and a plurality of gates are arranged sideways in a space between the reinforcement member and a wall surface of the cavity so as to flow the molten resin in the form of a plurality of divided streams into the cavity resin feed end of the cavity.
For the invention in the aspect, the molten resin composed of the first material and the second material having a color different from that of the first material and combined in a substantially separate manner is fed to the cavity in the form of a plurality of divided streams, and each of the divided streams composed of the second material enters into the cavity in a parabolic form by taking advantage of the flow characteristics of the plural divided stream and then disperses in a widthwise or transverse direction, i.e., toward the inside of the divided stream, while flowing toward the cavity resin reach end of the cavity. The widthwise extension of the end portion of the divided stream is restricted by the function that each of the adjacent divided streams acts as a sort of a wall of the divided stream, in association with the action that the end portion of the divided stream flows toward the cavity resin feed end thereof. However, while the widthwise extension of the divided stream of the first material is being restricted, the divided stream composed of the first and second materials is extended in a direction of elongation thereof and allowed to solidify with the trace of the divided stream retained thereon into a solidification layer, when solidified, that comprises a first solidification layer section and a second solidification layer section, the first solidification layer section being composed substantially of the first material and extending in a direction of elongation of the divided stream thereof
Iwase Kenju
Kadoki Takeshi
Morrison & Foerster / LLP
Naka Kogyo Co., Ltd.
Ortiz Angela
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