Plastic and nonmetallic article shaping or treating: processes – With measuring – testing – or inspecting – Positioning of a mold part to form a cavity or controlling...
Reexamination Certificate
1998-10-27
2001-12-18
Silbaugh, Jan H. (Department: 1732)
Plastic and nonmetallic article shaping or treating: processes
With measuring, testing, or inspecting
Positioning of a mold part to form a cavity or controlling...
C264S257000, C264S259000, C264S266000, C264S328700, C425S149000, C425S150000
Reexamination Certificate
active
06331263
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Filed of the Invention
The present invention relates to a method of producing laminated moldings utilized for car interior members and the like and, more particularly, to a method of producing laminated moldings intended to improve tactile feeling, quality of exterior and safety because the facing material is produced in an integrated state.
2. Description of the Related Art
Conventionally, a laminated molding covered with a facing material has been used as a car interior member (e.g., inside of a door and the roof, a seat) and the like. In the conventional laminated moldings, there is room for improvement in the quality of moldings and the facing material of the surface of the moldings.
For example, nice tactile feeling can be obtained and higher quality of exterior surfaces can be advanced by attaching raised cloth, thick cloth or similar material to the surface of the laminated moldings.
Otherwise, attaching thick cloth having cushioning characteristics on the surface, can improve safety for a driver and passengers in an automobile.
One means of producing laminated moldings is integrally molding by injecting resin in a molten state into the cavity in which the facing material is already seated. According to such integrated molding, it was not required to attach the facing material optionally, so that the productivity could be increased.
As recommended molding methods to produce such laminated moldings, there has been known in the art, for example, an injection compression molding method, an injection press molding method, a flow-stamping method or the like.
However, the conventional molding methods were known to involve the following disadvantages.
In the injection molding method depicted in
FIG. 16
, a clamping operation for the mold is started at a time t1 in order to feed the resin in the melting state toward the mold. A compressive force applied to the mold in the clamping operation is maintained at a predetermined pressure value SP until a time t5 when completing the injection molding. The facing material is compressed by an internal pressure of the resin stored in the mold while maintaining a position between the resin and the mold.
Consequently, when the facing material is sheet material such as raised cloth and the like, the characteristic of the sheet material having naturally nice tactile feeling, high quality and the like can degrade with the bowing and the raising of the sheet material as a result of the flat compression of the thick cloth and the like.
Since the facing material made of the sheet material having the cushioning characteristics melts with compression of the resin at high temperature and high pressure, the unique cushioning characteristics of the facing material are degraded when the laminated material is taken out from the mold.
Even if the compressive force is reduced by smoothing the flow of the resin in molding and thickening the thickness of the laminated moldings in order that the facing material is not compressed, the result is an increase in weight and material cost for the produced laminated moldings.
On the other hand, flow-stamping can reduce the internal pressure of the resin being compressed because the resin is supplied into a mold in a bonding state, so that a maximum flow distance of the resin in the mold becomes short. However, much time is needed for supplying the resin in the bonding state and the appearance of the produced laminated moldings tends to be inferior because the whole facing material solidifies in the compressed state if only a part of the facing material is solidified first as the surface of the resin solidifies by cooling.
The flow-stamping method includes a mechanism to take a nozzle in and out to flow the resin in the bonding state toward the mold, which should be accompanied with an interacting control system and requires a long molding cycle with much time needed for taking the nozzle in and out, so that the cost for producing becomes higher due to the molding apparatus having large-scale structure.
The disadvantages of the foregoing description are not always produced only in the laminated moldings used for the car interior members and the like but also in general laminated moldings covered the surface of the resin with the facing material.
It is an object of the present invention to provide the producing method of the laminated moldings intended to mold integrally the facing material.
SUMMARY OF THE INVENTION
The present invention relates to a method of producing laminated moldings molded from layers of facing material and resin supplied in the molten state to the mold having seated thereon the facing material. The present invention includes the steps of applying the compressive force to the mold to flow the resin until the resin fills up the cavity of the mold and then reducing the compressive force applied to the mold just before or after completing filling of the cavity with the resin.
The laminated moldings can be prepared using the following material, molding apparatus and molding procedures.
The resin, as a basic section of the laminated moldings, can be of thermoplastic resin and the like such as polyethylene, polypropylene, polystyrene, ABS(acrylonitrile-butadiene-styrene), polycarbonate, polyamide and the like. The such resin may be of homopolymer or copolymer, and more preferably, polypropylene or propylene-ethylene-copolymer (which are available to include filler such as talc and mica and a material to be filled into such as glass fiber, carbon fiber, organic fiber and the like).
In the above, a foaming agent need not be added to the resin forming the base of the laminated moldings. Conventionally, the resin base is foamed by adding foaming agent when the facing material is not protected enough and thereby not able to obtain enough cushioning property. The conventional resin base is foamed in order to prevent the molding from being ill-shaped thereby improving shape accuracy. However, since the mold of the present invention is not retracted to decrease the compressive force, the molding is continuously adhered to the mold and does not cause any ill-shape thereof even when the foaming agent is not added. Further, since the mold is not retracted, it is not fitted to employ a foaming agent. Though the facing material of the present invention is protected enough and has good cushioning property, if desired, to obtain more excellent cushioning property and thermal insulation property, or to reduce weight disregarding shortage in strength and rigidity, the base resin containing a foaming agent may be filled into the cavity, the resin having less volume than the final cavity volume for the space to be foamed. However, it is troublesome to determine the amount of the resin accurately, and the manufactured molding is likely to be inferior in the strength and rigidity thereof. Accordingly, it is preferable for the present invention to reduce weight of the moldings and improve thermal insulation ability by selecting the facing material without foaming the base resin.
The facing material is not limited but preferably is a fiber material sheet composed of fiber or a material sheet having cushioning characteristics.
The fiber material sheet includes all kinds of sheets composed of fiber, paper, or cloth, such as woven fabric, non-woven fabric, knitting fabric and the like.
Fiber can be natural fiber, such as plant fiber (cotton, hemp and another), animal fiber (sheep wool, silk and others), mineral fiber (asbestos and others) and the like, chemical fiber such as inorganic fiber (metallic fiber, glass fiber, carbon fiber and others), regenerated fiber, semisynthetic fiber, synthetic fiber (polyethylene, polypropylene, polyacrylonitrile, polyester, polyamide, polyvinyl chloride, polyurethane and others) and the like and mixtures of these natural fibers and chemical fibers.
The preferable fiber material sheet is of a raised sheet or a thick sheet because of the need of nice tactile feeling and a specific characteristic of natural quality, and more preferably, the raised cloth materi
Abe Tomokazu
Matsumoto Satoshi
Shimazaki Toshifumi
Flynn ,Thiel, Boutell & Tanis, P.C.
Idemitsu Petrochemical Co. Ltd.
Silbaugh Jan H.
Staicovici Stefan
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