Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From reactant having at least one -n=c=x group as well as...
Reexamination Certificate
2002-05-16
2004-04-06
Sellers, Robert (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From reactant having at least one -n=c=x group as well as...
C525S128000, C525S131000, C525S157000, C525S162000, 52
Reexamination Certificate
active
06716953
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to crosslinking agents having etherified carbamate functionality, and to curable compositions containing them.
BACKGROUND OF THE INVENTION
Coating compositions used in the original automotive equipment market are being called to more and more stringent performance requirements. Coating systems are expected to provide lasting weatherability, durability, resistance to acid etching, and mar resistance, while maintaining outstanding appearance properties. Coating systems used in certain applications, such as on plastic substrates, must also be flexible. Additionally, automotive coating compositions are expected to be available in environmentally friendly formulations.
Some coating compositions cured via acid-epoxy cure mechanisms, while providing excellent acid etch resistance, offer only marginal mar resistance. Conventional coating compositions cured with aminoplast crosslinking agents have been known for superior durability, but it has only been recently that aminoplast-cured coatings providing acid etch resistance have become available. Moreover, aminoplast-cured systems typically suffer from high photo-oxidation rates due to the breakdown of the aminotriazine ring inherently found in most aminoplast resins. Such degradation is due to prolonged exposure to ultraviolet light.
It would be desirable to provide crosslinking agents and curable compositions suitable for use as film-forming compositions in the automotive and industrial markets that overcome the drawbacks of the prior art, providing both appearance and performance properties now considered essential in automotive applications.
SUMMARY OF THE INVENTION
The present invention provides a reaction product of reactants comprising:
a) a polyisocyanate;
b) a hydroxyalkyl carbamate;
c) an aldehyde; and
d) at least one monohydric alcohol. The reaction product is suitable for use in a variety of curable compositions, which are also provided.
Additionally provided is a composition of matter comprising the structure:
wherein Q is a multi-valent organic moiety containing urethane linkages; X is H, —CH
2
OH, or —CH
2
OR′; R′ is an alkyl or aryl group having from 1 to 12 carbon atoms; and y is at least 2. The reaction product described above may have the structure (i).
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Other than in the operating examples, or where otherwise indicated, all numbers expressing quantities of ingredients, reaction conditions, and so forth used in the specification and claims are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties to be obtained by the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.
Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical values, however, inherently contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.
Also, it should be understood that any numerical range recited herein is intended to include all sub-ranges subsumed therein. For example, a range of “1 to 10” is intended to include all sub-ranges between (and including) the recited minimum value of 1 and the recited maximum value of 10, that is, having a minimum value equal to or greater than 1 and a maximum value of equal to or less than 10.
The reaction product of the present invention is typically prepared by reacting together:
a) a polyisocyanate;
b) a hydroxyalkyl carbamate;
c) an aldehyde; and
d) at least one monohydric alcohol.
The polyisocyanate a) may be selected from one or more polyisocyanates, such as diisocyanates and triisocyanates including biurets and isocyanurates. Biurets of any suitable diisocyanate including 1,4-tetramethylene diisocyanate and 1,6-hexamethylene diisocyanate may be used as reactant a) in the preparation of the reaction product of the present invention. Also, biurets of cycloaliphatic diisocyanates, such as isophorone diisocyanate and 4,4′-methylene-bis-(cyclohexyl isocyanate), can be employed. Examples of suitable aralkyl diisocyanates from which biurets may be prepared are meta-xylylene diisocyanate and &agr;,&agr;,&agr;′,&agr;′-tetramethylmeta-xylylene diisocyanate. The diisocyanates themselves may also be used as reactant a) in the preparation of the reaction product of the present invention.
Trifunctional isocyanates may also be used as reactant a), for example, trimers of isophorone diisocyanate, triisocyanato nonane, triphenylmethane triisocyanate, 1,3,5-benzene triisocyanate, 2,4,6-toluene triisocyanate, an adduct of trimethylol and tetramethyl xylene diisocyanate sold under the trade name CYTHANE 3160 by CYTEC Industries, and DESMODUR N 3300, which is the isocyanurate of hexamethylene diisocyanate, available from Bayer Corporation. Specifically used polyisocyanates are cyclic isocyanates, particularly, isocyanurates of diisocyanates such as hexamethylene diisocyanate and isophorone diisocyanate.
The polyisocyanate used as reactant a) may also be one of those disclosed above, chain extended with one or more polyamines and/or polyols using suitable materials and techniques known to those skilled in the art.
In the preparation of the reaction product of the present invention, the polyisocyanate reactant a) is used in an amount of 5 to 70 percent by weight, based on the total weight of reactants used to prepare the reaction product.
The hydroxyalkyl carbamate used as reactant b) typically contains about 3 to about 7 carbon atoms. Examples include hydroxyethyl carbamate, hydroxypropyl carbamate, hydroxybutyl carbamate, and the like. Reaction products of ammonia and hydroxyl functional carbonates, such as glycerin carbonate, are also suitable. Hydroxypropyl carbamate and hydroxyethyl carbamate are most often used. Reactant b) is used in an amount of 1 to 60 percent by weight, based on the total weight of reactants used to prepare the reaction product.
The aldehyde c) most often used in the preparation of the reaction product of the present invention is formaldehyde. Other aldehydes, such as acetaldehyde, propanaldehyde, butyraldehyde, furfural, benzaldehyde, acrolein, methacrolein, and glyoxal are also suitable. The aldehyde c) is used in an amount of 1 to 60 percent by weight, based on the total weight of reactants used to prepare the reaction product.
Alkylol groups formed during the reaction of a), b), and c) are at least partially etherified by reaction with at least one monohydric alcohol d). Any monohydric alcohol can be employed for this purpose. Particularly suitable alcohols may have up to 12 carbon atoms, most typically have from 1 to 6 carbon atoms, and include methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, pentanol, hexanol, cyclohexanol, and others, as well as benzyl alcohol and other aromatic alcohols, cyclic alcohols, such as cyclohexanol, monoethers of glycols, and halogen-substituted or other substituted alcohols, such as 3-chloropropanol and butoxyethanol. Most commonly, methanol, isobutanol, and/or n-butanol are used.
In the preparation of the reaction product of the present invention, the monohydric alcohol d) is used in an amount of 1 to 70 percent by weight, based on the total weight of reactants used to prepare the reaction product.
The urethane oligomer or polymer having carbamate functional groups may be alkylolated by reaction with an aldehyde. Examples of suitable aldehydes include those mentioned above, with formaldehyde being most often used. Alkylol
Barancyk Steven V.
Gaggini Sherry M.
Humphrey William A.
Mayo Michael A.
Valenta Jane N.
PPG Industries Ohio Inc.
Sellers Robert
Uhl William J.
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