Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
2001-01-25
2002-10-08
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...
C523S414000, C525S530000, C525S533000, C528S096000, C528S111300, C528S121000, C528S418000, C528S419000
Reexamination Certificate
active
06462106
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates a novel amino-polyether-modified epoxy and an electrodeposition paint composition containing the same.
BACKGROUND OF THE INVENTION
In order to protect metal materials from corrosion and keep their good appearance during using, they are provided with coating on the surfaces. Especially, as electrodeposition coating can simply and speedy form uniform coatings on surfaces of metal materials, it is industrially and widely used for coating metal materials having large surfaces to be coated, such as automobile bodies.
In an electrodeposited coating used in an automobile body, enhancement of adhesion with a substrate, an intermediate-coated or a top-coated coating provided on the substrate as well as enhancement of flexibility for improving chipping resistance are especially desired. Various compounds and resins are used to provide an electrodeposited coating with the flexibility.
For example, Japanese Laid-Open Patent Application Nos. 59-117560 and 6-87947 describe a cationic electrodeposition paint composition which contains a reaction product of polyepoxide with polyoxyalkylene amine.
However, when this reaction product is used as a component of a cationic electrodeposition paint composition, flexibility can be provided, but it adversely reduces adhesion with a substrate, an intermediate-coated or a top-coated coating provided on the substrate decreases.
Lately, it is strongly desired that an amount of solvent exhausted into air decrease, from a point of view of global environment, especially prevention of air pollution.
OBJECT OF THE INVENTION
The present invention solves the problems as mentioned above and an object of the present invention is to provide a novel amino-polyether-modified epoxy and a cationic electrodeposition paint composition using the same as a flexible resin, so as to impart flexibility to an electrodeposited coating, with keeping adhesion with a substrate, an intermediate-coated or a top-coated coating as well as to decrease an amount of solvent used in electrodeposition paint in comparison with conventional one.
DETAILED DESCRIPTION OF THE INVENTION
The present invention is a novel amino-polyether-modified epoxy obtained by reacting amino polyether represented by a formula as follow:
wherein m is an integer of 2 or more, R is hydrogen, methyl group or ethyl group, and n is 2 or 3,
with polyglycidyl ether having a molecular weight of 1,000 to 7,000 and an epoxy equivalent of 500 to 3,500, wherein an equivalent ratio of a primary amino group of the above amino polyether to an epoxy group of the above polyglycidyl ether is controlled within the range of 0.52 to 1.0.
In the above formula of the amino polyether, one example is that, m is an integer from 5 to 25, R is methyl group, and n is 2. It is preferred that a molecular weight of the amino-polyether-modified epoxy is within the range of 10,000 to 100,000.
The above polyglycidyl ether can be obtained from polyoxy alkylene glycol diglycidyl ether having a molecular weight of 500 to 1,000 and a polycyclic phenol compound. A dicarboxylic acid containing a long chain alkyl group can be added to the above two reactants. The above polyoxyalkyleneglycol diglycidyl ether may be polyoxypropyleneglycol diglycidyl ether and the above polycyclic phenol compound is bisphenol A. The above dicarboxylic acid containing a long chain alkyl group is a dimer acid. In addition, the present invention provides a cationic electrodeposition paint composition comprising a flexible resin comprising the above amino-polyether-modified epoxy, an amine-modified epoxy resin and a blocked polyisocyanate curing agent, for example the above amine-modified epoxy resin contains an oxazolidone ring.
An amino-polyether-modified epoxy of the present invention is characterized in that it is obtained by reacting amino polyether represented by a formula as follow:
wherein m is an integer of 2 or more, R is hydrogen, methyl group or ethyl group, and n is 2 or 3,
with polyglycidyl ether having a molecular weight of 1,000 to 7,000 and an epoxy equivalent of 500 to 3,500, wherein an equivalent ratio of a primary amino group of the above amino polyether to an epoxy group of the above polyglycidyl ether is controlled within the range of 0.52 to 1.0.
The above amino polyether can be obtained by adding alkylene oxide to monoethanol amine.
The above amino polyether, as represented by the above formula, has a polymethylene chain which has a primary amino group at one end and has a polyoxyalkylene chain having a terminal hydroxy group at the other end.
In the formula, m shows number of repeating units of polyoxyalkylene chain, which is preferably an integer from 5 to 25, more preferably an integer from 10 to 25. R in a polyoxyalkylene chain is preferably hydrogen or methyl group. In addition, R is usually the same, but may be two types or more. In the above formula, n represents number of repeating units of polymethylene chain bonding to a primary amino group and generally is 2 or 3, but 2 is more suitable.
The above polyglycidyl ether used in the present invention has a molecular weight of 1,000 to 7,000 and an epoxy equivalent of 500 to 3,500.
If polyglycidyl ether has a molecular weight of less than 1,000 and/or an epoxy equivalent of less than 500, an electrodeposited coating formed with a cationic electrodeposition paint containing an amino-polyether-modified epoxy obtained by using the polyglycidyl ether does not provide with sufficient flexibility. On the other hand, if polyglycidyl ether has a molecular weight of more than 7,000 and/or an epoxy equivalent of more than 3,500, adhesion between the electrodeposited coating and an intermediate-coated or a top-coated coating coated thereon decreases.
The above polyglycidyl ether compound can be obtained by reacting polyoxy alkylene diglycidyl ether having a molecular weight of 500 to 1,000 with a polycyclic phenol compound. The polyglycidyl ether compound can preferably be polyoxy alkylene glycol diglycidyl ether, which includes polyoxyethyleneglycol diglycidyl ether (epoxy ether of polyethylene glycol), polyoxypropyleneglycol diglycidyl ether, polyoxyisopropyleneglycol diglycidyl ether, polyoxybutyleneglycol diglycidyl ether and the like. Especially, polyoxyisopropyleneglycol diglycidyl ether is preferable.
The polyoxyalkyleneglycol diglycidyl ether preferably has a molecular weight of 500 to 1,000. If the molecular weights are less than 500, the resulting electrodeposited coating leads to decrease of impact resistance, and if the molecular weights are more than 1,000, adhesion with an intermediate-coated or a top-coated coating is defective.
The polycyclic phenol compound used herein can be one that used as a component in synthesis of an amine-modified epoxy resin that is a binder component in a general cationic electrodeposition paint composition. To be specific, it includes bisphenol A, bisphenol F, bisphenol S, phenol novolak cresol novolak, and the like. Especially, bisphenol A is preferable.
A molecular weight of the above polyglycidyl ether can be controlled by adjusting a formulating amount of the above polyoxy alkylene glycol diglycidyl ether and the above polycyclic phenol compound.
If necessary, the molecular weight can be also controlled by formulating a suitable amount of a dicarboxylic acid containing a long chain alkyl group. Examples of the dicarboxylic acids include 1,10-dodecane dicarboxylic acid, adipic acid and the like, especially, a dimer acid (available as, Barsadime 216) being preferable.
When the above thee components are polyoxyisopropyleneglycol diglycidyl ether, bisphenol A and dimer acid (available as, Barsadime), a formulating ratio can be controlled in 60 to 90/5 to 30/0 to 30 by weight to obtain a polyglycidyl ether having an objective molecular weight.
The amino-polyether-modified epoxy of the present invention is obtained by reacting the above amino polyether with the above polyglycidyl ether. When these two compounds are reacted, it is required that an equivalent ratio of a primary amino group of the above amino polyet
Shirakawa Shinsuke
Yamada Mitsuo
Aylward D.
Dawson Robert
Nippon Paint Co. Ltd.
Wenderoth , Lind & Ponack, L.L.P.
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