Stock material or miscellaneous articles – Composite – Of polyester
Reexamination Certificate
1999-10-27
2003-11-25
Dixon, Merrick (Department: 1774)
Stock material or miscellaneous articles
Composite
Of polyester
C428S478800, C428S479300
Reexamination Certificate
active
06652983
ABSTRACT:
TECHNICAL FIELD
The present invention relates to in-mold decorating sheets, as well as in-mold decorated articles using the same, for use in decorating the surfaces of molded resin products of three-dimensional shape including interior automotive trims such as console boxes, center clusters, and switch bases, exterior automotive trims such as side mudguards, bumpers, wheel covers and braid, and component parts for household electrical appliances such as refrigerator doors and air-conditioner front panels.
BACKGROUND ART
As a surface decorating method, there has been known an in-mold decorating method using an in-mold decorating sheet. This method comprises setting into an injection mold an in-mold decorating sheet with a pattern layer formed thereon, clamping the mold, injecting a molten molding resin into a cavity, and allowing the molding resin to set, where a pattern-layer side of the in-mold decorating sheet is integrally bonded to the surface of the molded resin product, by which an in-mold decorated article is obtained.
After the molding, an unnecessary portion of the in-mold decorating sheet that has not been bonded to the molded resin product is removed by trimming. The trimming process may be a process of burning out an insert film by irradiating a laser beam, a process of making a punch die for trimming and punching an insert film by pressing, a process of removing by human hand as if it were torn, or the like.
However, the in-mold decorating sheets obtained by these processes have had the following issues, respectively.
A first issue is deficiencies of the trimming process, or peeling of the in-mold decorating sheet from the molded resin product during the trimming process.
That is, in the process using a laser beam for trimming, there has been an issue that too much radiation of the laser beam would cause the vicinity of the trimming portion to burn and thereby discolor due to the heat of the laser beam. Also, in the process using a punch die, there has been an issue that too large a pressing force would cause the punch die to deteriorate in sharpness with time. Further, in the process with human hand, there has been an issue that inappropriate work would cause the in-mold decoration sheet to be partly peeled off from the molded resin product before the in-mold decorating sheet is cut. Such issues are caused due to the deficiency in adhesion between the in-mold decorating sheet and the molding resin and/or to the fact that the in-mold decorating sheet itself is hard to cut. Such issues are caused due to the deficiency in adhesion between the in-mold decorating sheet and the molding resin and/or to the fact that the in-mold decorating sheet itself is hard to be cut.
A second issue is the peeling of the in-mold decorating sheet from the molded resin product due to shrinkage of the molding resin. This occurs when there is a large difference between the shrinkage rate of the molded resin product that occurs within 24 hours after the molded resin product that has formed by injecting and then setting the molding resin is removed from the injection mold (i.e., the shrinkage rate of the molding resin), and the shrinkage rate of the in-mold decorating sheet until the in-mold decorating sheet that has been heated during the injection molding turns back to normal temperature (for example, with an interior automotive trim, this issue occurred when the in-mold decorating sheet was an acrylic printed film and the molding resin was polypropylene resin, where the shrinkage rate of the former was about 4/1000 and that for the latter was about 15/1000).
That is, when an in-mold decorating sheet
94
and a molded resin product
93
formed by the setting of molding resin are integrated into an in-mold decorated article
95
(see
FIG. 5A
) and then cooled, a strong bonding force between the in-mold decorating sheet
94
and the molded resin product
93
of the set molding resin would cause a warp to occur to the whole in-mold decorated article
95
along with a deformation of the molded resin product
93
of the set molding resin (see FIG.
5
B).
Also, a weak bonding force between the in-mold decorating sheet
94
and the molded resin product
93
of the set molding resin would cause a minute shift to occur between the bonding surface of the in-mold decorating sheet
94
and the bonding surface of the molded resin product
93
of the set molding resin, resulting in the peeling of the in-mold decorating sheet
94
from the molded resin product
93
of the set molding resin at the end
95
a
of the in-mold decorated article
95
or other faults (see FIG.
5
C).
A third issue is that in a desire for an in-mold decorated article of deep drawing with a design of metallic luster, the pattern layer of the in-mold decorating sheet is largely stretched, causing craze (micro cracks) to occur so that the metallic luster is reduced, making the in-mold decorated article unusable.
In such applications as exterior automotive trims including side braid and bumpers, many products are of metallic-like design. In this case, conventionally, there have been generally used products in each of which an in-mold decorating sheet obtained by dry-laminating both of a film having chromium vacuum-deposited coating formed on a weatherproof polyester film and a bonding film together is integrally bonded to the surface of the molded resin product. However, this is not applied to molded resin products of deep-drawn shape for the aforementioned reason.
Therefore, it is an object of the present invention to provide an in-mold decorating sheet which is free from any deficiency in adhesion with molding resin or which itself is easy to cut, as well as an in-mold decorated article using the in-mold decorating sheet.
A further object of the present invention is to provide an in-mold decorating sheet which is hard to be peeled from the molding resin and is difficult to warp, as well as an in-mold decorated article using the in-mold decorating sheet.
A further object of the present invention is to provide an in-mold decorating sheet in which even in a case of obtaining an in-mold decorated article of deep drawing with a design of metallic luster, even though its pattern layer of the in-mold decorating sheet is largely stretched, the sheet yields less craze (micro cracks), and less reduction in metallic luster, as well as in-mold decorated article using the in-mold decorating sheet.
DISCLOSURE OF THE INVENTION
In order to accomplish the above object(s), the present invention has the following constitutions.
According to a first aspect of the present invention, there is provided an in-mold decorated article obtained by: setting an in-mold decorating sheet in an injection mold; after the mold is clamped, injecting molten molding resin into the mold; after cooling and solidifying of the injected molding resin, integrally bonding a part of the in-mold decorating sheet to a surface of the molding resin; and then, removing a remaining unbonded portion of the in-mold decorating sheet, wherein when the in-mold decorating sheet is peeled off from an interface with the solidified molding resin in compliance with conditions of ASTM D903, the in-mold decorating sheet has a peel strength of at least not less than 1 kgf/inch width or the in-mold decorating sheet breaks at the interface before reaching the peel strength.
According to a second aspect of the present invention, there is provided an in-mold decorated article as defined in the first aspect, wherein a difference in shrinkage rate between the in-mold decorating sheet and the after-solidifying molding resin is 0/1000-8/1000.
According to a third aspect of the present invention, there is provided an in-mold decorated article as defined in the first or second aspect, wherein when a tensile test is carried out with a 10 mm wide test specimen of the in-mold decorating sheet fixed between a pair of chucks with an opposite end edge distance of 100 mm, by applying a load at a constant speed of 5 mm/sec to the test specimen at one end thereof under an ambient temperature condition of 25° C
Dixon Merrick
Nissha Printing Co. Ltd.
Wenderoth , Lind & Ponack, L.L.P.
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