Stock material or miscellaneous articles – Composite – Of epoxy ether
Patent
1996-08-27
1998-06-16
Lusignan, Michael
Stock material or miscellaneous articles
Composite
Of epoxy ether
427379, 427386, 427410, 523412, 525438, B32B 2738
Patent
active
057667675
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a thermocurable coating composition which is suitable for an automotive top coating composition or a coil coating composition, and to a process for forming a cured film using the coating composition and to an article having the cured film thereon.
BACKGROUND OF THE INVENTION
A coating composition for top coating an automobile generally contains, as a film forming binder, a combination of a hydroxyl group-containing polymer and a melamine resin. The cured film obtained from the melamine curing system, however, has poor acid resistance and is damaged by acid rain which has recently become one of serious problems. The damage of the film provides poor appearance.
In order to overcome the above mentioned defects, the present inventors have proposed novel coating compositions without employing the melamine resin in Japanese Kokai Publications 45577/1990 and 287650/1991. The proposed coating compositions comprises a polymer having a carboxyl and carboxylate group derived by half-esterifying an anhydride group, and a polymer having an epoxy group or an epoxy and hydroxyl group. Since the composition cures by means of a reaction of the carboxyl group with the epoxy group as well as carboxylate group with hydroxyl group, and it forms a cross-linking point made of ester bond. Therefore, the resulting cured film has good acid resistance and sufficient weather resistance for an automotive top coating.
However, to achieve good acid and weather resistance, the cured film have to have high cross-linking density, and the coating composition for forming the cured film have to comprise a reactive resin of high functionality, and it becomes essentially poor in storage stability. Therefore, there has been a continued need for methods in order to impart excellent storage stability to the coating composition comprising a reactive resin of high functionality.
SUMMARY OF THE INVENTION
The present invention solves the problem above described, and the object is to provide a coating composition having excellent curability and excellent storage stability, which provides a cured film having good weather resistance, particularly excellent acid resistance. The present invention also provides a process for forming a cured film and a coated article using the coating composition.
The present invention provides a liquid coating composition comprising: resin solid of an onium salt.
The coating composition of the present invention is suitably used for a clear coating composition. The present coating composition is useful for coating any conventional coated or uncoated substrate. For example, the present coating composition may be employed for coating a pre-coated surface, as for what we call top coating composition. The pre-coated surface include, for example, a surface coated by cured or uncured solid colored film and a surface coated by cured or uncured composite film.
The present invention also provides a process for forming a cured film on a substrate comprising: intercoated surface of the substrate; substrate without curing a base coating layer; and comprises the coating composition described above.
DESCRIPTION OF THE INVENTION
The present invention provides a liquid coating composition comprising: resin solid of an onium salt.
Preferably, the present coating composition further comprises 0.01 to 6.0 parts by weight based on 100 parts by weight of the total resin solid of a metal salt of organic sulfonic acid (d).
The compound having at least 2 carboxyl groups (a) employed in the present coating composition is not particularly limited, and may be any compound having an average of at least 2 carboxyl groups per molecule. Examples of preferred polymer (a) include a polymer having carboxyl groups (a") which has an acid value of from 30 to 300 mgKOH/g solid and a number average molecular weight of 500 to 50000.
Preferred polymer (a") includes an acrylic polymer having carboxyl groups (a"1) and a polyester polymer having carboxyl groups (a"2). The acrylic polymer having carboxyl
REFERENCES:
patent: 3065195 (1962-11-01), Vasta
patent: 4275290 (1981-06-01), Dudgeon
patent: 5128018 (1992-07-01), Kiesele
patent: 5218018 (1993-06-01), Tominaga et al.
patent: 5276097 (1994-01-01), Hoffman et al.
patent: 5369178 (1994-11-01), Miyazaki et al.
Fushimi Akira
Hisai Tsuneyoshi
Okude Yoshitaka
Sasaki Shigeyuki
Takagi Takeshi
Lusignan Michael
Nippon Paint Co. Ltd.
LandOfFree
Coating composition process for forming cured film and coated ar 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 composition process for forming cured film and coated ar, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Coating composition process for forming cured film and coated ar will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1723180