Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Reexamination Certificate
2000-07-07
2002-05-07
Dawson, Robert (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
C524S589000, C524S560000, C524S601000
Reexamination Certificate
active
06384119
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to coating compositions comprising volatile, linear siloxane fluids. More particularly, the invention relates to coating compositions useful in the automotive manufacturing industry which have improved resistance to visual defects caused by surface contamination and exhibit improved gloss and/or distinctness of image (DOI).
BACKGROUND OF THE INVENTION
Coatings applied to surfaces typically serve decorative and/or protective functions. This is particularly so for automotive finishes, which must provide an esthetically appealing appearance while simultaneously meeting and maintaining rigorous performance and durability requirements. As used herein, “automotive coating or finish” encompasses both original equipment (OEM) coatings and refinish coatings, but especially to refinish coatings, the later term referring to coatings which are applied after the car has left the manufacturer, usually for repair purposes. It will be appreciated that automotive coatings are typically required to possess optimum application and performance parameters.
For example, automotive coatings must generally exhibit exceptional gloss, depth of color, and distinctness of image (DOI). An extremely high degree of clarity is necessary to achieve these desired visual effects. High gloss coatings also require a low degree of visual aberrations at the surface in order to achieve a desired visual effect such as high DOI.
One way that the automotive industry has met these challenges, especially original equipment manufacturers (OEM), involves the use of color-plus-clear composite coatings for use in the manufacture of automotive body panels. As used herein, the term “composite color-plus-clear” relates to composite coating systems requiring the application of a first coating, typically a colored basecoat, followed by the application of a second coating, generally a clearcoat, over the noncured or “wet” first coating. The applied first and second coatings are then cured. Thus, such systems are often described as “wet on wet” or “two-coat/one bake”. Drying processes that fall short of complete cure may be used between the application of the coatings.
Automotive refinishers must provide appearance and performance equal to those obtained by the OEMs but must provide such performance requirements without benefit of the controlled application environments and high temperature cure ovens used in the OEM facilities. Refinish operations may involve the repair of one or more outer coating layers, the repair or replacement of entire automotive body components, or a combination of both. The terms “refinish coating” or “repair coating” may be used interchangeably.
Automotive refinishers have often met these challenges with the use of two-component coating compositions. As used herein, the term “two-component” refers to the number of solutions and/or dispersions which are mixed together to provide a curable coating composition. Up until the point of mixing, neither of the individual components alone provides a curable coating composition.
Thus, both OEMs and automotive refinishers seek to provide coating compositions with high gloss and high DOI. However, these coating compositions are often susceptible to visual defects believed to be caused by surface contamination. Examples of such defects include “fisheyes” or “craters” and “telegraphing”. For the purposes of the instant application, the terms “fisheyes” and “cratering” may be used interchangeably. However, these terms as used herein refer solely to defects believed to result from surface contamination and not to defects resulting from solvent vapors and the like.
Fisheyes or craters are round concave depressions in the film that may or may not have raised edges. They vary in size from barely visible to more than 0.25 inches (6 mm) in diameter and may be deep enough to reveal the surface under the paint. While not wishing to be bound by a particular theory, it is believed that these defects result from the repulsion of the paint by contaminants on the surface of the substrate. They may occur singly in isolated events or in mass, with several hundred giving a mottled effect to the film.
Telegraphing refers to a visual defect wherein the pattern or location of a surface contaminate is visible in the cured film. For example, if an attempt is made to wipe away a contaminate, the wipe marks can ‘telegraph’ through the surface of the cured film, i.e., the wipe marks may be visible in the cured film.
Common contaminants believed to cause visual defects such as fisheyes and telegraphing include but are not limited to fats, oils, greases, silicones, and a variety of cosmetics and personal care products. Those skilled in the art appreciate that such visual defects are some of the most challenging paint defects to prevent or cure. They often appear suddenly and without warning, persist for a time and then disappear just as suddenly as they appeared. The presence of even one crater or fisheye may be an unacceptable defect which can result in the scrapping or repainting of an entire part or substrate.
Although products intended to eliminate such defects are known they often result in paint films having significant recoatability problems. That is, subsequently applied coating layers fail to adhere to the previously applied coating layer containing the fisheye eliminating product. Both OEM and automotive refinish compositions must be capable of adhering to subsequently applied coating compositions.
Accordingly, fisheyes and/or telegraphing present an expensive and difficult problem for the automotive finishing industry. Coating compositions of all types having improved resistance to such visual defects have long been sought.
It is thus an object of the invention to provide a coating composition having improved resistance to visual defects caused by surface contamination and which is suitable for use in both OEM and automotive refinish facilities.
Moreover, it is a further object of the invention to provide a coating composition which has improved DOI while still maintaining improved resistance to visual defects caused by surface contamination.
The prior art has failed to satisfy these requirements of the automotive finishing industry.
U.S. Pat. No. 5,256,191 discloses a correction fluid composition comprising an opacifying pigment dispersed in a solution of a film-forming polymeric material and from 10 to 40 weight percent of a volatile organosiloxane, based on the total weight of the correction fluid, wherein the organosiloxane and a solvent are present in a particularly defined volume ratio.
U.S. Pat. No. 4,476,278 discloses a dust-proof coating composition consisting of (A) 100 parts of an alkyd resin, (B) 5 to 200 parts by weight of methyltrimethoxysilane,(C) a curing catalyst, and (D) 50 to 5000 parts by weight of a solvent mixture consisting of (a) a volatile organosilicon compound which has a boiling point of 70° to 250° C. at atmospheric pressure and has a formula selected from the group consisting of (R
1
)
4
Si, (R
2
)
3
SiO[(R
3
)
2
SiO]
m
Si(R
2
)
3
R
4
Si[OSi(R
5
)
3
]
3
and [(R
6
)
2
SiO]
n
wherein R
1
to R
6
respectively represent the same or different alkyl groups, m represents 0 or a positive integer and n represents a positive integer of 3 or above, and (b) a hydrocarbon solvent substantially free of methanol, wherein the amount of (a) is 5 to 95 wt. % of the total amount of (a) and (b).
JP 59105057 discloses a dust-proofing coating composition consisting of (A) 100 parts by weight alkyd resin, (B) 5 to 500 parts by weight organic silicon compound and (C) 50 to 5000 parts by weight of mixed solvent. The organic silicon compound (B) consists of a mixture of at least 5 parts weight (a) organosilane or organosiloxane having on average at least two hydrolysable groups per molecule and 0 to 100 parts weight (b) polyorgano siloxane with blocked terminal silanol groups having a viscosity of at least 100,000 cSt at 25 degrees C.
However, none of the prior art have resolved the problems ad
Rihan Ali A.
Tye Anthony J.
Dawson Robert
Golota Mary E.
Peng Kuo-Liang
LandOfFree
Coating compositions comprising volatile linear siloxane fluids does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Coating compositions comprising volatile linear siloxane fluids, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Coating compositions comprising volatile linear siloxane fluids will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2913233