Plastic and nonmetallic article shaping or treating: processes – Mechanical shaping or molding to form or reform shaped article – To produce composite – plural part or multilayered article
Reexamination Certificate
2000-10-30
2003-06-03
Kuhns, Allan R. (Department: 1732)
Plastic and nonmetallic article shaping or treating: processes
Mechanical shaping or molding to form or reform shaped article
To produce composite, plural part or multilayered article
C264S259000, C156S245000
Reexamination Certificate
active
06572808
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a laminated molding integrated with flexible surface member and a process for manufacturing the laminated molding.
BACKGROUND ART
Conventionally, a laminated molding integrated with flexible surface member is used as interior parts of an automobile such as a sun visor and headrest and as an airflow control valve of an automobile air conditioner.
Since a surface of such laminated molding is covered with the flexible surface member, good feel can be obtained in touching by hand.
Further, since a desired cushion property can be obtained by increasing thickness of the surface member, the laminated molding can be used to a component such as a lid of a console box, thus restraining shock sound in opening and shutting and vibration during drive.
Furthermore, since the surface member having cushioning property can seal a gap, good sound insulation and sealing can be given to an airflow control valve when it is applied to an airflow control valve of an automobile air conditioner.
As a process for manufacturing the laminated molding, following manufacturing processes have been conventionally used.
Method A
Manufacturing the laminated molding by attaching the surface member by an adhesive etc. onto a surface of a molding previously manufactured by an injection molding process.
According to the above process, since the surface member has to be attached onto each molding, productivity can be deteriorated on account of work for the attaching process and, furthermore, sufficient attachment strength cannot be obtained by the attaching process with the use of adhesive.
Method B
Filling molten resin between two surface members attached with anti-penetration sheet disposed in a die and press-molding thereof (Japanese Patent Publication No. Hei 2-25806).
According to the above--method, since a nozzle of an extruder has to be advanced and retracted relative to the die for every time filling the molten resin, cycle time for molding one molding product can be lengthened. Further, since the anti-penetration sheet has to be attached to the surface member, manufacturing process can be troublesome.
Method C
After closing a die disposed with two surface members thereinside, injecting and filling molten resin into the die while retaining low pressure and cooling the molten resin to solidify while keeping low dwell pressure (Japanese Patent Publication No. Hei 3-60297).
According to the above method, since the injection pressure is kept relatively low, it requires considerable time to fill the molten resin, thus increasing cycle time, and furthermore, sufficient cushion property cannot be obtained according to material of the surface member.
For solving the problems associated with the respective methods, another method has been proposed (Japanese Patent Application Laid-Open Publication No. 8-127042), where, after a surface member is attached to a molding surface of a compression core on a movable die side, the compression core is advanced to compress the filled molten resin, thus manufacturing a laminated molding integrated with the surface member.
As a material of the surface member, especially for airflow control valve of an air conditioner of an automobile, polyurethane foam is proposed as well as polyethylene foam and polypropylene foam.
According to the manufacturing method of the above invention, cycle time can be reduced without impairing quality of the surface member.
However, though no special problem occurs when the material of the surface member is a foam of polyethylene and polypropylene etc., on account of properties of polyurethane foam different from the other foams, polyurethane foam can be damaged or wrinkled under the same molding condition as the polyethylene etc., a laminated molding having good properties cannot always be obtained.
DISCLOSURE OF THE INVENTION
An object of the present invention is to provide a laminated molding having a surface member made of urethane foam with good properties and a process for manufacturing the same.
A laminated molding according to first aspect of the present invention has a thermoplastic resin base and an ether type urethane foam provided at least one side of the base, the ether type urethane foam mainly made of polyether polyol, which is characterized in that the thermoplastic resin base and the urethane foam are integrally attached by injection compression molding or injection molding under a pressure loading of average pressure relative to project area of a molding cavity of not more than 50 kg/cm
2
.
The pressure loading refers to a pressure applied to the resin in the die. It refers not only the compression force in the injection compression molding but also includes injection pressure in the injection molding.
The project area of the molding cavity is, in other words, an area of the molding product in a direction orthogonal with open/shut direction of the die.
A laminated molding according to second aspect of the present invention has a thermoplastic resin base and an ester/ether type urethane foam provided at least one side of the base, the ester/ether type urethane foam mainly made of polyester polyol and polyether polyol, which is characterized in that the thermoplastic resin base and the urethane foam are integrally attached by injection compression molding or injection molding under a pressure loading of average pressure relative to project area of a molding cavity of not more than 50 kg/cm
2
.
The ester/ether type urethane foam includes 10 to 60 wt % of polyester polyol.
The ether type urethane foam and the ester/ether type urethane foam constitute the surface member for the thermoplastic resin base.
The urethane foam can be classified mainly into three types, i.e. ester type urethane foam, ether type urethane foam and ester/ether type urethane foam.
Though the ester type urethane foam is superior in heat resistance, mechanical strength and non-air-permeability, it is hydrolytic and inferior in moist heat aging property. Further, it costs relatively expensive.
Though the ether type urethane foam is not hydrolytic and superior in moist heat aging property, it is inferior in heat resistance and mechanical strength. Further, it cost relatively inexpensive.
The ester/ether type urethane foam is similar to the ether type urethane foam in properties thereof and air permeability (air tightness) can be easily controlled.
Accordingly, since the ether type urethane foam or the ester/ether type urethane foam has characteristics different from the ester type urethane foam, manufacturing condition should be in accordance with the characteristics of the urethane foams.
Specifically, since the ether type urethane foam and the ester/ether type urethane foam are low in heat resistance and strength, when attaching to the base simultaneously with molding step under the same condition as the surface member made of polyester etc, the urethane foams may be broken or wrinkled on account of high temperature and high pressure. Further, the thickness of the urethane foam may be decreased under high temperature and high pressure to lower shock absorption or may be hardened to deteriorate touch thereof.
Accordingly, the present invention has been reached by discovering that, when the urethane foam is ether type or ester/ether type, the above problem of damage on the polyurethane foam can be restrained by integrally attaching the base with the urethane foam under a pressure loading of average pressure of not more than 50 kg/cm
2
, preferably between 30 to 5 kg/cm
2
relative to project area of the molding cavity. The present invention is especially suitable for attaching the ether type urethane foam with the thermoplastic resin base, however, the present invention can also be suitably used for ester/ether type urethane foam.
As a foaming agent of the urethane foam, various foaming agent such as water, flon, methylene chloride etc. can be used.
Though expansion ratio is not restricted, a range of 25 to 100 is appropriate for a sealing member.
Air permeability is preferably not more than 50 cc/cm
2
/second when it is
Fukushima Terunobu
Saito Yoshiaki
Flynn ,Thiel, Boutell & Tanis, P.C.
Idemitsu Petrochemical Co. Ltd.
Kuhns Allan R.
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