Coating processes – Restoring or repairing
Reexamination Certificate
2000-06-16
2002-01-15
Dawson, Robert (Department: 1712)
Coating processes
Restoring or repairing
C427S142000, C427S410000, C523S402000, C523S403000, C523S404000, C523S423000, C523S424000, C428S413000
Reexamination Certificate
active
06338869
ABSTRACT:
The present invention relates to a coating composition capable of forming a coating film having a good performance when coated on a deteriorated coating film surface of a coating film formed from a tar epoxy resin coating material, a tar urethane resin coating material, a modified epoxy resin coating material, a modified urethane resin coating material, an epoxy-polyamine resin coating material or an epoxy urethane resin coating material without subjecting the deteriorated coating film to pre-treatment, and a coating method thereof.
In large size steel structures such as marine vessels and bridges which are exposed to a corrosive environment, high corrosion-protective coating materials such as a tar epoxy resin coating material, a tar urethane resin coating material, a modified epoxy resin coating material, a modified urethane resin coating material, an epoxy-polyamine resin coating material and an epoxy urethane resin coating material are coated on upper structures, decks, holds, ballast tanks, cargo tanks and outside plates of marine vessels; and outside plates, girder outside surfaces and girder inside surfaces of bridges from a viewpoint of corrosion protection.
These large size steel structures have usually as long building and constructing periods as 3 to 24 months, and therefore coating films of a tar epoxy resin coating material, a tar urethane resin coating material, a modified epoxy resin coating material a modified urethane resin coating material, an epoxy-polyamine resin coating material and an epoxy urethane resin coating material are usually exposed in an outdoor for not much longer than 1 to 12 months.
In general the coating films of these resin bases are inferior in a weatherability, and a deterioration of the coating films such as discoloration, glaze reduction and chalking is brought about if they are exposed in an outdoor over a long period of time. This deterioration is notably observed in the coating film of a tar epoxy resin coating material or a tar urethane resin coating material.
If a prescribed coating material is applied directly on coating films which are formed by applying the coating materials of the resin bases described above and which are exposed in an outdoor over a long period of time during building, constructing or using and deteriorated, an adhesive property between this applied coating film and the deteriorated coating films is markedly inferior, and therefore brought about is the defect that the problems of cracking and peeling are caused many times during a building, constructing or using period.
With respect to a countermeasure therefor, when a coating material is applied on the deteriorated coating film described above, a deteriorated layer on the surface of the resin base coating film described above is removed by blast treatment or removing treatment using a power tool, a hand tool or high pressure washing, and then a prescribed coating material is applied. However, a lot of labor and cost is required for removing this deteriorated coating film, and therefore strongly desired to be developed are a coating material capable of forming a coating film having a good corrosion prevention on the above deteriorated coating film without providing such removing step and causing the problems of cracking and peeling on the above deteriorated coating film, and a coating method.
Further, the coating films of the resin bases described above are deteriorated not only by exposure but also by submerging without treating the deteriorated coating film, and if a prescribed coating material is applied on a coating film which is deteriorated by submerging, an adhesive property between the applied coating film and the deteriorated coating films is markedly inferior, so that the problems of cracking and peeling are brought about many times during a building, constructing or using period.
An object of the present invention is to provide a coating composition capable of forming a coating film having good performances such as an adhesive property even if coated on a deteriorated coating film surface of a coating film formed by applying a tar epoxy resin coating material, a tar urethane resin coating material, a modified epoxy resin coating material, a modified urethane resin coating material, an epoxy-polyamine resin coating material or an epoxy urethane resin coating material without subjecting the deteriorated coating film to pre-treatment, and a coating method thereof.
The present inventors paid attentions to the fact that in a deterioration phenomenon of a coating film caused by the outdoor exposure and submerging described above, a part of resin components (an epoxy resin, a curing agent and other jointly used resins) contained in the coating film was deteriorated to form a carboxyl group and considered that if the carboxyl group in this deteriorated coating film would be chemically bonded to a part of components of a coating material applied on the deteriorated coating film, an adhesive property between the coating films might be able to be improved. As a result of carrying out various investigations, it has been found, to be unexpected, that the object described above can be achieved by using a coating composition of an organic solvent type or solventless type epoxy resin-amine curing agent system and adding a prescribed amount of water to the coating composition, and the present invention has come to be completed.
Thus, the present invention provides a coating composition of an organic solvent type or solventless type comprising an epoxy resin having at least one epoxy group in a molecule and an amine base curing agent as resin components, wherein moisture of 1 to 30 parts by weight per 100 parts by weight of the solid matter of the coating composition is contained.
Further, the present invention provides a coating method characterized by applying the preceding coating composition provided by the present invention on a deteriorated coating film surface of a coating film formed by applying a tar epoxy resin coating material, a tar urethane resin coating material, a modified epoxy resin coating material a modified urethane resin coating material, an epoxypolyamine resin coating material or an epoxy urethane resin coating material.
The coating composition of the present invention and the coating method thereof shall be explained below in further details.
First, the coating composition of the present invention shall be explained.
Epoxy Resin
The epoxy resin which is used in the coating composition of the present invention as a resin component is a resin having at least one epoxy group, preferably at least two epoxy groups on an average and more preferably 2 to 5 epoxy groups on an average in a molecule, and it has suitably a number average molecular weight falling in a range of usually about 250 to about 3,000, preferably about 360 to about 1,000 and an epoxy equivalent falling in a range of usually about 80 to about 1,000, preferably about 180 to about 500.
The epoxy resin described above includes, for example, glycidyl ether type epoxy resins, glycidyl ester type epoxy resins, other glycidyl type epoxy resins and alicyclic epoxy resins; modified epoxy resins based on these epoxy resins; and epoxy group-introduced alkylphenol or alkylphenol novolak type resins prepared by reacting alkylphenol or alkylphenol novolak type resins with epichlorohydrin.
The glycidyl ether type epoxy resins described above include, for example, epoxy resins having a glycidyl ether group which can be obtained by reacting polyhydric alcohols and polyhydric phenols with epihalohydrin or alkylene oxides. Examples of the polyhydric alcohols described above include divalent alcohols such as ethylene glycol, polyethylene glycol, propylene glycol polypropylene glycol, neopentyl glycol, butylene glycol and hexanediol; trivalent alcohols such as glycerin, trimethylolethane and trimethylolpropane; pentaerythritol, diglycerin and sorbitol. Examples of the polyhydric phenols described above include 2,2-bis(4-hydroxyphenyl)propane-[bisphenol A], 2,2-bis(2-hydroxyphenyl)propane, 2-
Inomata Shigeo
Nakano Tadashi
Saito Akira
Aylward D.
Dawson Robert
Kansai Paint Co. Ltd.
Wenderoth , Lind & Ponack, L.L.P.
LandOfFree
Coating composition 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, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Coating composition will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2828402