Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
2000-12-28
2002-11-26
Sanders, Kriellion A. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C524S261000, C524S196000, C524S366000, C524S418000, C524S539000, C524S594000
Reexamination Certificate
active
06486239
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a polyester based coating composition for anti-stain PCM outside panel and more particularly, to the polyester based coating composition for anti-stain PCM outside panel having an excellent combination of physical properties such as surface compactness, anti-contamination effect, acid resistance and self-cleaning effect, wherein the polyester based coating composition comprises:
a) hydroxyl unsaturated polyester resin and a melamine curing agent as main ingredients, b) sulfonic acid blocked with a secondary amine or epoxy resin, c) sulfonic acid blocked with a tertiary amine, d) an isocyanate compound blocked with malonate, e) a tin based curing catalyst, f) polyalkyl silicate, and g) an alkoxy compound; further, the polyester based coating composition for anti-stain PCM outside panel can demonstrate other excellent properties such as appearance and workability even without addition of any defoaming agent and leveling agent by adjusting the compatibility of both hydroxy unsaturated polyester resin and polyalkyl silicate.
2. Background of the Invention
Recently, environment-related multifunctional technologies have been spotlighted and in parallel with this trend, there is an increasing demand for electronic products using a pre-coated metal (PCM) technology in the related field, together with the growing interest in special in- and out-door contamination. In particular, there is a rapidly increasing demand for anti-contaminating paints to preserve the brilliant view of city in the PCM paint field of building materials.
In view of the structural form, the currently used outside panel for building are divided into high quality product for use in a high-story building and low quality product for use in a low-story building. As far as the high-story buildings are concerned, paint based on containing fluorine resin with high weatherability has been mainly employed for long term durability of buildings, while maintaining the appearance of building through periodic washing. On the other hand, the low-story buildings have maintained little cleanliness due to initially established low durability, and their outside panel during architecture has been made using a color steel plate coated by a film of paint containing polyester melamine resin with low durability. Among other things, the first priority should be placed on the maintenance of the initial building appearance, while sustaining the durability and anti-contamination effect of the film of paint. There is an urgent need for film the high degree of property self-cleaning of paint to be naturally washed by rainwater, even though an architectural PCM steel panel is contaminated.
To achieve the aforementioned object, the inventor filed a patent invention relating to a self-cleaning PCM steel plate (Korea Unexamined Patent No. 2000-47283). During the actual application, however, the self-cleaning PCM steel plate has shown some disadvantages in that (1) in spite of some self-cleaning effect, the panel could not be maintained for more than two years, (2) an excessive amount of melamine cross-linking resin for the improvement of cross-link density in the film of paint has resulted in significant changes in physical properties during the coating process, and when the coated plate collided with other iron steel, black scratch traces such as metal mark were present at the surface of the film of paint, thus being a cause of client s complaint.
To effectively prevent from the contamination of rainwater in the film of paint, the U.S. Pat. No. 6,013,721 has disclosed a coating composition comprising a partial hydrolyzed condensate, wherein tetramethoxy silane is hydrolyzed less than 100% and condensed; hence, the partial hydrolyzed condensate contains less than {fraction (1/10)} of the molar ratio of silanol group and methoxysilyl group ([SiOH]/[SiOMe]), 0 to 30 wt. % of 2~8 monomers and tetramethoxy silane having the molecular weight of 1,500 to 5,000.
In general, in the case of a paint containing a silicate compound with silanol group, an easier infiltration of water-soluble oxidants into a hydrophilic metal substrate has resulted in lowering the chemical resistance with poor storage stability via rapid reaction between a hydroxy group and a silanol group (SiOH) within resin, and magic contamination.
SUMMARY OF THE INVENTION
To free from the aforementioned shortcomings, therefore, an object of this invention is to provide a polyester based coating composition for anti-stain PCM outside panel having an excellent combination of physical properties such as surface compactness, anti-contamination, acid resistance and self cleaning capacity, wherein the polyester based coating composition comprises:
a) hydroxy unsaturated polyester resin and a melamine curing agent as main ingredients, b) sulfonic acid blocked with a secondary amine or epoxy resin, c) sulfonic acid d blocked with a tertiary amine, d) an isocyanate compound blocked with malonate, e) a tin based curing catalyst, f) polyalkyl silicate, and g) an alkoxy compound.
Further, this coating composition for anti-stain PCM outside panel demonstrate excellent appearance and workability even without the addition of any defoaming agent and leveling agent by adjusting the molecular weight ranges of both hydroxy unsaturated polyester resin and polyalkyl silicate.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
This invention is characterized by a polyester based coating composition for anti-stain PCM outside panel comprising a hydroxy unsaturated polyester resin, a melamine curing agent, a curing accelerator, a supplemental curing agent, a supplemental curing accelerator, a storage stabilizer and a curing catalyst, wherein said polyester based coating composition further comprises:
a) 40 to 80 wt. % of the hydroxy unsaturated polyester resin;
b) 5 to 50 wt. % of the melamine curing agent;
c) 0.5 to 3 wt. % of sulfonic acid blocked with a secondary amine or epoxy resin;
d) 0.001 to 3 wt. % of sulfonic acid blocked with a tertiary amine;
e) 1 to 10 wt. % of an isocyanate compound blocked with malonate;
f) 0.1 to 2 wt. % of a tin based curing catalyst, f) 0.5 to 10 wt. % of polyalkyl silicate expressed by the following formula; and
g) 1 to 5 wt. % of an alkoxy compound,
wherein R
1
, R
2
, R
3
, R
4
, R
5
and R
6
are independently alkyl groups of C
1-5
; and n is an integer of 5 to 80.
This invention is explained in more detail as follows.
This invention relates to a polyester based coating composition for anti-stain PCM outside panel which can improve significantly the durability of a film of paint with strong resistance against outer contaminants, wherein it comprises a hydroxy unsaturated polyester resin and a melamine curing agent as main ingredients, sulfonic acid blocked with a secondary amine or epoxy resin as a curing accelerator, sulfonic acid blocked with a tertiary amine as a supplemental curing accelerator, an isocyanate compound blocked with malonate as a supplemental curing agent, a tin based curing catalyst, polyalkyl silicate as a surface modifier expressed by the formula 1, and an alkoxy compound as a storage stabilizer.
This invention is explained in more detail about each chemical composition contained in the coating composition.
The hydroxy unsaturated polyester resin according to this invention refers to polyester based resin with hydroxy group; unsaturated polyester, oil-modified polyester and their modified resins such as urethane-modified unsaturated polyester or urethane-modified/oil-modified polyester. It is preferred that the hydroxy unsaturated polyester resin according to this invention is selected from the material with a number average molecular weight of 1,500 to 8,000, a glass transition temperature of −15 to 60 and OH value of 15 to 180, more preferably with a number average molecular weight of 2,000 to 7,000, a glass transition temperature of −5 to 45 and OH value of 20 to 150.
The oil-modified polyester of this invention can be prepared via a reaction be
Jin Chang Il
Lee Jin Hyung
Lee Joon Ho
Park Sung Uk
Sohn Joo Lak
Kumgang Korea Chemical Co., Ltd.
Lowe Hauptman & Gilman & Berner LLP
Sanders Kriellion A.
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