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
1999-11-02
2001-09-11
Cooney, John (Department: 1711)
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...
C528S044000, C528S080000, C528S083000, C528S085000, C560S024000, C560S025000, C560S026000, C560S330000, C560S354000
Reexamination Certificate
active
06288199
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to new, blocked isocyanate-based compounds. The invention also relates to a new family of polymeric compositions made with these blocked isocyanate-based compounds.
BACKGROUND OF THE INVENTION
Blocked isocyanate compounds which react at elevated temperature with compounds containing active hydrogen atoms to produce three-dimensional or networked polymers by forming crosslinks between preformed molecules are known and are described, for example in Houben-Weyl,
Methoden der Organischen Chemie,
Vol. XIV/2, pages 61-70, or in Z. W. Wicks, Jr.,
Progress in Organic Coatings
9, 3-28 (1981). For example, liquid and powder coating compositions, adhesives, rigid and moldable plastics and foams comprising, among other things, a blocked isocyanate-based compound have been employed in almost every manufacturing industry. Conventional blocking agents for isocyanate compounds include phenols, caprolactam, oximes and CH-acid compounds such as acetoacetic acid esters and malonic acid dialkyl esters.
Blocked isocyanate-based compound have been used in combination a wide variety of polyols to produce polyurethanes. Such polyurethanes can be formed into rigid and flexible foamed articles, sheets, high density sheets and articles of various shapes. Moreover, the light stability of such polyurethanes makes them extremely useful in liquid and powder coatings, as well as being useful in other applications where light stability is desirable.
Although blocked isocyanate-based compounds are known, the various manufacturing industries which employ the same are continually searching for new compounds of this type.
SUMMARY OF THE INVENTION
One object of this invention is to provide novel isocyanate-based compounds which can be used as crosslinkers.
Another object of this invention are polymeric compositions which include novel isocyanate-based compounds as crosslinkers.
The novel isocyanate-based compounds of the present invention can be used in essentially all applications where conventional isocyanate-based compounds are employed. In other words, the isocyanate-based compounds of the present invention can be used in the making of liquid and powder coating compositions, adhesives, rigid and moldable plastics and foams.
The achievement of this and other objects will become apparent to those skilled in the art after reading this specification. The isocyanate-based compounds of the present invention include a polyfunctional isocyanate compound which is at least partially blocked with at least one of the following: a polyhydroxy aromatic compound, or a mixture of a polyhydroxy aromatic compound and a hydroxy-functional ester compound.
DETAILED DESCRIPTION OF THE INVENTION
The novel isocyanate-based compounds of the present invention comprise a polyfunctional isocyanate which is at least partially blocked with at least one of the following: a polyhydroxy aromatic compound, or a mixture of a polyhydroxy aromatic compound and a hydroxy-functional ester compound.
Although blocked isocyanates are known to those skilled in the art, what is not known is that these types of compounds can adequately function when they are at least partially blocked in the manner set out below. Specifically, in accordance with the present invention, the novel isocyanate-based compounds are at least partially blocked with at least one of the following: a polyhydroxy aromatic compound, or a mixture of a polyhydroxy aromatic compound and a hydroxy-functional ester compound.
As used herein, the term “polyhydroxy aromatic compound” includes compounds having at least one of the following structures:
HO—&PHgr;
1
—R
1
—&PHgr;
1
—OH (I)
where &PHgr;
1
is an aromatic-containing compound which comprises a phenyl group, and R
1
is an alkyl group having 0 to 4 carbon atoms, or
HO—&PHgr;
2
—OH (II)
where &PHgr;
2
is an aromatic containing compound which comprises a phenyl group or a naphthyl group.
Examples of the polyhydroxy aromatic compounds which are encompassed by structure (I) include: diphenols such as 4,4′-isopropylidenediphenol (e.g., BISPHENOL™ A, commercially available from Dow Chemical Co) and bis (4-hydroxyphenyl) methane (e.g., BISPHENOL™ F, also commercially available from Dow Chemical Co). Examples of polyhydroxyl aromatic compounds which are encompassed by structure (II) include: dihydroxynaphthalene, hydroxy phenols such as resorcinol, and derivatives thereof. In certain preferred embodiments of this invention, the polyhydroxy aromatic compound comprises 4,4′-isopropylidene-diphenol.
As used herein, the term “hydroxy-functional ester compound” includes compounds having the following structure:
COOR
2
—&PHgr;
2
—OH (III)
where, R
2
is an alkyl group having from 1 to 4 carbon atoms, and &PHgr;
2
is an aromatic containing compound which comprises a phenyl group or a naphthyl group.
In structure (III), although &PHgr;
2
is an aromatic containing compound which comprises a phenyl group or a naphthyl group, in certain preferred embodiments, &PHgr;
2
is an aromatic containing compound which comprises a phenyl group.
Examples of the hydroxy-functional ester compounds which are encompassed by structure (III) include: methyl 4-hydroxy benzoate, methyl 3-hydroxy benzoate, and the like. In certain preferred embodiments of this invention, the hydroxy-functional ester compound comprises methyl 4-hydroxy benzoate.
As stated above, the polyhydroxy aromatic compounds encompassed by structures (I) and (II) can be used exclusively as blocking agents for the novel isocyanate-based compounds of the present invention. However, in certain preferred embodiments, the novel isocyanate-based compounds are at least partially blocked with a blend of the polyhydroxy aromatic compound(s) and the hydroxy-functional ester compound(s) encompassed by the following structures: (I) and (III); (II) and (III); and/or (I), (II) and (III).
In the embodiments wherein the novel isocyanate-based compounds are at least partially blocked with a blend of the polyhydroxy aromatic compound(s) and the hydroxy-functional ester compound(s), the ratio of the polyhydroxy aromatic compound(s) to the hydroxy-functional ester compound(s) typically ranges from about 0.01:1 to about 1.4:1. In certain embodiments where a blend of these blocking agents are employed, the ratio of the polyhydroxy aromatic compound(s) to the hydroxy-fumctional ester compound(s) preferably ranges from about 0.05:1 to about 1:1.2, and more preferably, from about 0.10:1 to about 1:1.
When at least partially blocking the novel isocyanate-based compounds in accordance with certain embodiments of the present invention, the total amount of the blocking agent(s) employed are such that there exists from about 1.5 to about 0.6 hydroxyl equivalents of the blocking agent(s) per equivalent of free NCO in the isocyanate-based compound. In certain preferred embodiment, the total amount of the blocking agent(s) employed are such that there exists from about 1.3 to about 0.7 hydroxyl equivalents of the blocking agent(s) per equivalent of free NCO in the isocyanate-based compounds; and more preferably, from about 1.1 to about 0.9 hydroxyl equivalents of the blocking agent(s) per equivalent of free NCO in the isocyanate-based compounds.
Any suitable polyfunctional isocyanate can be at least partially blocked in accordance with this invention. In one embodiment, the polyfunctional isocyanate is derived from a polyisocyanate (i.e., an isocyanate possessing at least two isocyanate functions, advantageously more than two) which is itself typically derive from a precondensation or from a prepolymerization of elemental isocyanates. Elemental isocyanates include those made of hydrocarbon skeletons having at least two isocyanate functions. These hydrocarbon skeletons are often an arylene radical, an alkylene radical (including an aralkylene radical) such as the polymethylenes (e.g., hexamethylene), or the necessary to form isophorone diisocyanate (IPDI). The hydrocarbon skeletons may also be alkyl(s) or arylic.
The atomic weight
Ambrose Ronald R.
Chasser Anthony M.
Retsch, Jr. William H.
Cooney John
PPG Industries Ohio Inc.
Uhl William J.
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