Coating processes – With post-treatment of coating or coating material – Heating or drying
Patent
1990-09-21
1992-09-08
Lusignan, Michael
Coating processes
With post-treatment of coating or coating material
Heating or drying
427381, 4274071, 427408, 4274121, 525129, 525131, B05D 302
Patent
active
051457210
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to a method of coating articles with a base coat and a top coating, the top coat including polytetrafluoroethylene (hereinafter referred to as PTFE) fluorine resins. The articles may, for example, be plastics and wooden products such as unit baths, bathtubs, bath articles, tableware, yachts, and pools.
BACKGROUND ART
Fluorine resins include Polyvinylfluoride resins (PVF), Polyvinylidenefluoride (PVdF), Polychlorotrifluoroethylene (PCTFE), Polytetrafluoroethylene resins (PTFE), Fluorinated ethylene-propylene copolymer resins (FEP), and Tetrafluoroethylene-perfluoroalkylvinylether copolymer resins (PFA), and it has been known that they have excellent properties. For example, they are non-tacky, have a low coefficient of friction and a good chemical resistance, and are electrical insulators. Particularly, PTFE and PFA have excellent properties.
To utilize the excellent properties of fluorine resins, attempts are being made to coat various products with the fluorine resins.
However, as the fluorine resins (particularly PTFE and PFA) have extremely high melting points (about 300.degree. C.) a coat of the fluorine resins could not be applied direct to plastics having melting points lower than those of these resins.
In products such as unit baths, particularly, FRP resins are used as raw materials, but as their melting points are as low as 120.degree.-140.degree. C., a direct PTFE resin finishing of the raw material surface can not be conducted.
In recent years, therefore, a number of fluorine resin-mixed type coating materials have been invented, and methods have been adapted to apply a coat of these materials to a material surface to be coated.
Such conventional fluorine resin coating materials have an inconvenience in that they show the characteristics of fluorine resins early in the application to a product, but they peel away when used for a long time because of their lack of adhesion to the coated material surface.
Therefore, it is an object of this invention to provide a method of coating with PTFE resins, which makes it easy to apply the resins to plastic products and gives excellent adhesion of coating materials to the products.
DISCLOSURE OF THE INVENTION
Namely, this invention achieves the present object by a method of applying a polytetrafluoroethylene coating material to a material to be coated comprising:
(a) a step of adding 2-10 wt % of a polytetrafluoroethylene or polytetrafluoroethylene-perfluoroalkylvinylether copolymer resin to a polyester polyol or acrylic polyol followed by stirring,
(b) a step of mixing a polyisocyanate with the solution prepared in the step (a) in a ratio of 1:1-4:1 just before coating and sufficiently stirring the mixture followed by coating, and
(c) a step of conducting initial drying at 60.degree. C. or less after the coating and then natural drying at room temperature.
The second invention further achieves the present object by a coating method of a polytetrafluoroethylene coating material to a material to be coated, which comprises:
(a) a step of adding 2-10 wt% of a polytetrafluoroethylene or polytetrafluoroethylene-perfluoroalkylvinyl ether copolymer resin to an unsaturated polyester resin followed by stirring,
(b) a step of mixing an oxidizing agent with the solution prepared in the step (a) just before coating and sufficiently stirring the mixture followed by coating, and
(c) a step of conducting initial drying at 60.degree. C. or less after the coating and then natural drying at room temperature.
As the polyisocyanates to be mixed with the solution, aromatic polyisocyanates in the case of polyester polyol and aliphatic polyisocyanates in the case of acrylic polyol are used.
The polyester polyol used in this invention can be obtained by the condensation reaction of a polybasic acid with a polyhydric alcohol.
The polybasic acid is a compound containing two or more carboxyl groups in one molecule, and the polyhydric alcohol is a compound containing two or more hydroxyl groups in one molecule.
As the acrylic polyols, vari
REFERENCES:
patent: 4483900 (1984-11-01), Goldfarb
patent: 4863986 (1989-09-01), Re et al.
patent: 4923929 (1990-05-01), Ohwada et al.
Kojima Takeshi
Nakajima Taketoshi
Haruhiko Murakami
Lusignan Michael
LandOfFree
Method of coating an article with a polytetrafluoroethylene coat does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of coating an article with a polytetrafluoroethylene coat, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of coating an article with a polytetrafluoroethylene coat will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-133275