Adhesive bonding and miscellaneous chemical manufacture – Surface bonding means and/or assembly means therefor – Presses or press platen structures – per se
Reexamination Certificate
2000-03-27
2001-10-02
Osele, Mark A. (Department: 1734)
Adhesive bonding and miscellaneous chemical manufacture
Surface bonding means and/or assembly means therefor
Presses or press platen structures, per se
C156S345420, C100S057000, C029S426300, C029S239000, C264S037300
Reexamination Certificate
active
06296035
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus for removing a coating from a coated synthetic resin product such as, for instance, a bumper or a side molding which is used as decoration for an automobile or a functional part serving as a buffer, or a CD-ROM or the like.
2. Description of the Related Arts
In recent years, due to rising interest in environmental problems and reuse of resources, the recycling of synthetic resin products has been advocated. For instance, in the automobile industry, attention is being given to the recycling of unusable products produced in the manufacturing process of resin products such as bumpers and side moldings, or the recycling of resin products removed and recovered from scrapped vehicles.
These kinds of resin products such as bumpers and side moldings are often coated in order to improve their external appearance and quality. For instance, in the case of a typical bumper, a film is coated on a resin material consisting of a thermoplastic resin such as a polypropylene resin, via a primer layer of a thermoplastic resin such as a chlorinated polyolefine resin. This coating is a thermosetting resin such as an amino-polyester resin, an amino acrylic resin, a polyester urethane resin or an acrylic urethane resin. Although these resins are liquid prior to curing, a cross-linking structure is formed therein by a baking finish process. Since this structure is strong and hard, the coated resin bumper has superior chemical resistance, heat resistance, abrasion resistance, weather resistance and surface glossiness.
However, when this coated bumper is directly crushed for reuse, the polypropylene resin material serving as the base material of the resin product becomes contaminated with coating pieces. When such a polypropylene resin material contaminated with the coating pieces is molded, the fluidity of the molten resin is inhibited by the presence of the coating pieces, with the result that molding defects such as “burning”, “weld marks” and “air bubbles” may occur in the resin product, and the coating pieces rising to the surface of the resin product may spoil the external appearance of the resin product.
Furthermore, although the coating pieces are thermosetting resin, the polypropylene resin serving as a base resin is a thermoplastic resin. Therefore, there is no appreciable interaction between the coating pieces and the base resin, so that kneading of the regenerated recycled resin is inhibited by the coating pieces which have not been minutely dispersed, with the consequence that the mechanical property of the recycled resin product notably deteriorates and the application range of the recycle resin product is greatly restricted.
It is therefore necessary to remove the coating when recycling the coated resin product. An apparatus for removing a coating from a resin product is disclosed in Japanese Patent Laid-Open No.5-337941, which proposes a removing apparatus for the surface of a synthetic resin product as illustrated in FIG.
16
.
In this removing apparatus, a resin product, such as a side molding
102
, is carried by a pair of conveying rollers
101
between rolls
103
and
104
which are made from a synthetic resin foam. The carrying speed V of the side molding
102
is set to be lower than the rotational peripheral speed of the rolls
103
and
104
so as to apply cutting and high frictional forces to a coating
102
a
and a double face adhesive tape
102
b
on the surfaces of the side molding
102
, thereby cutting and removing the coating
102
a
and the pressure sensitive double face adhesive tape
102
b
. The side molding
102
is thus delivered outside the system by means of the pair of conveying rollers
101
.
However, in this apparatus, a resin product is brought into contact with rolls
103
and
104
which are made of a foamed resin, so that the rolls
103
and
104
are subject to brittle fracture which may generate dust and worsen the working environment. Furthermore, this apparatus is unsuitable for use with bent or curved resin products.
A countermeasure against these problems is disclosed in Japanese Patent Laid-Open Publication No. 7-25664, which illustrates a method for removing a coating from resin material, wherein a resin body having a coating thereon is rolled through a coat removing apparatus, comprising a pair of rolls rotating at different peripheral speeds which are provided facing the coated resin body, and a shear stress is applied between the resin material and the coating thereby removing the coating from the resin material.
In the case of this apparatus, a resin body is rolled between rolls having different peripheral speeds which are provided facing the resin body, and a shear stress is applied to the interface between the resin body and the coating thereby removing and removing the coating from the resin material. For this reason the coating removal rate is high. Furthermore, there is no toxicity since no solvents or the like need be used, and consequently this method has superior environmental safety.
However, when the resin bodies from which coating is to be removed differ in thickness, the size of the gap between the rolls must be adjusted in accordance with the thickness of the resin bodies in order to apply a suitable shear stress to the resin material. Furthermore, when the parts of the same resin body have different thickness, it is difficult to apply a uniform shear stress to the entire surface of the coating, which is likely to reduce coating removal efficiency.
SUMMARY OF THE INVENTION
The present invention provides an apparatus for removing a coating from resin bodies, comprising rolls rotating at different peripheral speeds from each other, and allowing a coated resin body to pass between the rolls while applying a shear stress to the interface between the resin body and the coating, and capable of automatically applying a uniform pressing force even in the cases when the coated resin bodies have different thicknesses or an individual coated resin body has parts with different thicknesses, thereby raising the efficiency for removing the coating and improving productivity.
In order to achieve the above object, a coating removing apparatus of the present invention comprises two rolls with a roll gap therebetween, the rolls being provided in parallel to allow a synthetic resin body having a coating thereon to pass between the roll gap; roll drive means for rotating a coating side roll of the two rolls, the coating side roll contacting the coating, at a different peripheral speed and in a different direction from another synthetic resin body side roll of the two rolls, and causing a shear stress between the coating and the synthetic resin body passing through the roll gap, thereby removing the coating; and pressing means for applying a predetermined force to the rolls so as to force them closer together.
Since the pressing means applies a predetermined force to the rolls, forcing them closer together, a uniform pressing force can be applied to the entire surface and a uniform shear stress can be applied between the resin material and the coating, even when coated resin bodies from which coatings are to be removed have different thicknesses or when an individual coated resin body has parts with different thicknesses, thereby making it possible to raise coating removal efficiency and improve productivity.
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pate
Watanabe Toshikazu
Yamamoto Hiroshi
Fuji Jukogyo Kabushiki Kaisha
Osele Mark A.
Smith , Gambrell & Russell, LLP
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