Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
2002-05-06
2003-07-15
Dawson, Robert (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C525S438000, C525S449000, C525S471000, C525S523000
Reexamination Certificate
active
06593401
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a powder coating composition containing a low temperature curable epoxy resin, and more particularly to a powder coating composition containing a low temperature curable epoxy resin, which can be readily cured at a low temperature, thereby capable of being applied to coating objects that are difficult in elevating temperature, or are thermally sensitive.
2. Description of the Related Art
Epoxy resin is a molecule having two or more epoxy functional groups. Epoxy resin is a kind of thermosetting resin irreversibly crosslinked to form a three-dimensional structure at room temperature or under the influence of heat. However, epoxy resins are different from other thermosetting resins in that curing is not carried out on heating in the absence of a catalyst or a curing agent. An epoxy resin is widely used in molded products, cast products, coatings and the like due to its excellent adhesion, mechanical property, electrical property, chemical resistance, etc.
In particular, the epoxy resin is excellent in adhesion, water resistance, and chemical resistance to various types of coating objects, including metals. Accordingly, the epoxy resin based coatings are widely used instead of alkyd resin or phenolic resin based coatings.
A powder coating composition is a coating film forming composition in the form of powder and does not use a volatile solvent such as an organic solvent or water. The powder coating composition is applied to a coating object and then heat-melted. The powder coating composition has advantages in that it does not use a solvent, can form a thick coating film with just one coating, and can use a high molecular weight resin which is not dissolved in a solvent, compared with a solvent-type coating composition. Accordingly, use and demand for the powder coating composition are increasing in fields of construction materials, automobile parts, pipes, mechanical parts, electronic products, iron furniture and the like.
The powder coating composition is generally produced as follows: a resin for a powder coating composition, a curing agent, a pigment and an additive, and the like are mixed in a blender. The mixture is placed into an extruder or a roll-mill, where it is heated at a temperature in a range of 80 to 130° C., melt-mixed and ground into a powder. Thereafter, a coating object is coated with the ground powder coating composition. Alternatively, the powder coating composition can be produced by mixing the above components in a mixer such as a ball-mill or a ribbon blender at room temperature.
The powder coating composition can be coated by various coating techniques, for example, a spray coating technique, a flow coating technique or an electrostatic coating technique. The electrostatic coating technique is most widely used.
Examples of the resin for the powder coating composition are an epoxy resin and a polyester resin. The epoxy resin is generally a bisphenol-A epoxy resin manufactured by reacting bisphenol-A and epichlorohydrin in the presence of a base or an acid. The bisphenol-A epoxy resin is excellent in chemical resistance and corrosion, resistance. However, because it is cured at a high temperature, for thick metallic coating objects that cannot reach an elevated temperature within a short time, a large amount of heat energy must be applied thereto, and thus energy use increases. Further, it is difficult to apply to coating objects that are thermally sensitive.
SUMMARY OF THE INVENTION
Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to provide a powder coating composition containing a low temperature curable epoxy resin with corrosion resistance.
REFERENCES:
patent: 4623701 (1986-11-01), Massingill
Kim Jin-woo
Park Chongsoo
Park Young-soo
Yu Jinseon
Aylward D.
Bacon & Thomas
Dawson Robert
Kukdo Chemical Co., Ltd.
LandOfFree
Low temperature curable epoxy resin, method for preparing... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Low temperature curable epoxy resin, method for preparing..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Low temperature curable epoxy resin, method for preparing... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3090135