Solid material comminution or disintegration – Apparatus – With temperature modification of material
Reexamination Certificate
2002-08-12
2004-03-09
Rosenbaum, Mark (Department: 3725)
Solid material comminution or disintegration
Apparatus
With temperature modification of material
C241S260100
Reexamination Certificate
active
06702211
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a coating film peeling method and a coating film peeling apparatus of a coated resin product for peeling a coating film from the coated resin product having the coating film on the surface of a base resin material.
2. Description of the Related Art
A recycling of resin products has been demanded in recent years for the environmental problems or for the reclamation of resources. In the field of automobile industries, for example, there has also been noted the recycling of the in-process defectives, which are made when the resin products such as bumpers or body side moldings are manufactured, or the resin products which are separated and recovered from scrapped cars.
The resin products such as bumpers are often coated on their surfaces so as to improve the appearances and qualities. In a bumper made of a resin, for example, a base material layer
101
of a resin is generally coated on its surface with a coating layer
103
through a primary layer
102
, as sectionally shown at a essential portion in FIG.
14
.
The base material layer
101
is made of a mixture, which is prepared by mixing a base of a thermoplastic synthetic resin or polypropylene with ethylene-propylene rubber and a filler such as talc, and is formed into a layer having a specific gravity of 0.91 to 0.98 and a thickness t of about 2 mm to 4 mm.
The primer layer
102
is made of an adhesive layer having a specific gravity of about 1.7 and a thickness of about 10 microns so as to strengthen the bonding power of the base material layer
101
and the coating layer
103
. The coating layer
103
is formed by applying a paint coating which is made of a thermoset synthetic resin such as melamine or polyurethane.
When the bumper is crushed and pelletized to obtain a reclaimed material, however, the coating film chips are included in the polypropylene resin making the base material layer
101
. In the molding process using the polypropylene resin material including the coating film chips, these coating film chips will obstruct the fluidicity of the molten resin to cause a defective molding in the resin product. At the same time, the coating film chips will float to the surfaces of the resin product and deteriorate the appearances of the resin product. Because of few interactions between the coating film chips and the polypropylene resin, moreover, the coating film chips will obstruct the kneading of the reclaimed resin to degrade the mechanical properties of the resin product.
When the coated resin product is to be recycled, therefore, it is essential to remove the coating films.
This coating film removing method is classified coarsely into the mechanical, physical and chemical methods. The mechanical coating film removing method is exemplified by a shot blast method and a screen mesh method. The shot blast method is for breaking and removing the coating films or deposits by blasting abrasive particles with compressed air, for example, to the coating film surface formed on the resin product. The screen mesh method is for removing the coating film chips not melted but included, by pulverizing the resin product finely and then by filtering the fine chips being heated and melted through a screen mesh.
The shot blast method removes the coating films by the frictions and impacts and is excellent in the non-toxic properties and the environmental safety. Despite of these excellences, however, the shot blast method takes a long time for the treatment but is neither sufficient in the coating film removing efficiency nor easy for the treatment of curved portions. On the other hand, the screen mesh method is also excellent in the non-toxic properties and the environmental safety because it removes the coating film chips through the filtration. When the screen mesh is clogged, however, the extrusion pressure seriously rises to reduce the extrusion and the productivity and to have an insufficient efficiency for removing the coating film chips. The screen mesh has to be replaced so as to avoid the reduction, as caused by the clogging, in the production efficiency.
The physical coating film removing method uses a halogen solvent or various organic solvents to remove the coating films by making use of the penetration of the solvent into the interface between the coating films and the base material and the swelling phenomenon of the coating films by the solvent. Therefore, the physical coating film removing method is inferior in the environmental safety for the disposal of the waste liquid and is poorer in the coating film removing efficiency and the treating capacity but may deteriorate the base material.
Since these mechanical and physical coating film removing methods are poor in the coating film removing efficiency, the resin product using the resin material reclaimed by those methods is high in the production cost so that its application is seriously restricted.
The chemical coating film removing method is exemplified by the organic salt method for decomposing and removing the coating film chemically by cutting the ether bonds in the vicinity of the bridges of the coating film resin with an aqueous solution of ethanol containing an organic salt.
This method has a problem in the secondary treatment such as the wastewater treatment and has a poor treating capacity so that it is not preferable for the treating efficiency.
As disclosed in Japanese Patent Unexamined Publication No.
5-337941,
on the other hand, there has been proposed a synthetic resin surface peeling apparatus for cutting and peeling the coating films by applying the cutting force and the frictional force to the coating films by a pair of rotary members.
In this peeling apparatus, as schematically shown in a front elevation in FIG.
12
and in a sectional view of line I—I of
FIG. 12
in
FIG. 13
, a resin product such as a body side molding
122
is transferred between rollers
123
and
124
made of a foamed synthetic resin by a pair of conveyor rollers
121
. By setting the transfer velocity V of the body side molding
122
lower than the circumferential velocity of the rollers
123
and
124
, high cutting and frictional forces are applied to the coating film
122
a
and the double adhesive tape
122
b
of the body side molding
122
to cut and peel the coating film
122
a
and the double adhesive tape
122
b
from the surface of the body side molding
122
. By the paired conveyor rollers
121
, moreover, the body side molding
122
is discharged to the outside.
In this apparatus, the resin product is brought into contact with the rotating rollers
123
and
124
made of the foamed synthetic resin. Therefore, the rollers
123
and
124
will have brittle fracture to generate dust unfavorably for the working environment. On the other hand, the apparatus is not suited for peeling the coating films from bent or curved resin products.
SUMMARY OF THE INVENTION
In view of the points thus far described, therefore, a first object of the invention is to provide a coating film peeling method for a coated resin product, which is excellent in the coating film removing efficiency, the environmental safety and the treating capacity to produce recycled resin products of a high quality.
Moreover, a second object of the invention is to provide a coating film peeling apparatus for a coated resin product, which is constructed to execute the aforementioned coating film peeling method simply at a low cost.
In order to achieve the aforementioned first object, a the invention of a method for peeling a coating film of a coated resin product comprises: coarsely crushing the coated resin product having a base resin material coated with the coating film; and conveying thus coarsely crushed products of the coated resin product while rubbing the same to peel the coating film from the base resin material.
According to the invention, by neither employing chemicals such as organic salts or solvents nor requiring a secondary treatment such as the wastewater treatment, moreover, the coated resin products can be
Fuji Jukogyo Kabushiki Kaisha
Rosenbaum Mark
Smith , Gambrell & Russell, LLP
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