Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From carboxylic acid or derivative thereof
Reexamination Certificate
2000-12-08
2003-11-25
Dawson, Robert (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From carboxylic acid or derivative thereof
C564S153000, C564S193000, C564S197000, C564S198000
Reexamination Certificate
active
06653436
ABSTRACT:
1. FIELD OF INVENTION
This invention relates to aqueous dispersions of epoxy resins. In one aspect, the invention relates to improved aqueous dispersions of epoxy resins, which provide improved coating properties and a process to prepare such dispersions.
2. BACKGROUND OF THE INVENTION
Aqueous dispersions of epoxy resins have been known for many years. However, the performance of these dispersions as elements of coatings has been viewed as inferior to their solvent borne counterparts. It is known that the surfactants employed to render the epoxy component emulsifiable such as nonylphenol ethoxylates, alkylphenol initiated poly(oxyethylene) ethanols, alkylphenol initiated poly(oxypropylene) poly(oxyethylene) ethanols, and block copolymers containing an internal poly(oxypropylene) block and two external poly(oxyethylene) ethanol blocks readily migrate to surface interfaces where, it is speculated, they deleteriously affect film performance.
Moreover, as aqueous dispersions of epoxy resins have become more widely used in industry, improved handling properties such as storage stability are required. The storage stability of many water borne epoxy dispersions degrades over time due to the presence of amine nitrogen atoms in the surfactant molecules. As the pH of water borne dispersions increases over 9.8, the storage stability can no longer be measured in years, but rather is measured in months.
It would also be desirable to decrease the particle size of the solids, or decrease the amount of surfactant required at a given solids level, or to disperse solids at a given particle size using less surfactant. Often, a larger amount of surfactant needed to decrease the particle size and effectively disperse the solids in water leads to increased pH and reduced storage stability. Decreasing the surfactant level to control the pH causes an increase in particle size.
3. SUMMARY OF THE INVENTION
There is now provided a surfactant which effectively lowers the pH of an epoxy resin water borne dispersion while maintaining small particle sizes.
According to the invention, there is provided an amidoamine composition comprising oligomeric amidoamine compounds having the structure:
wherein each R′ is independently hydrogen or an alkyl group containing 1-6 carbon atoms provided that at least one R′ is hydrogen, preferably two R′ are hydrogen, most preferably all four R′ are hydrogen, R
2
is an aliphatic, cycloaliphatic, or aromatic residue of a primary amine compound having 2 to 24 carbon atoms and optionally containing non-reactive oxygen or at most an average of 4 secondary and/or tertiary nitrogen atoms in the backbone of the primary amine compound, and preferably R
2
is an aliphatic moiety having from 2 to 8 carbon atoms, the average of x based on the amidoamine composition is at least 0.2, and Z comprises the residue of a polyoxyalkylene polyether polycarboxylic acid compound; wherein the amidoamine composition comprises the reaction product of primary polyamine compounds with polyoxyalkylene polyether polycarboxylic acid compounds at a corresponding equivalent weight ratio of at least 4.0:1 under oligomeric reaction conditions effective to increase the amine nitrogen equivalent weight of the amidoamine composition by at least 10% over the average acid equivalent weight of said polyoxyalkylene polyether polyacid composition.
In another aspect of the invention, there is provided an amidoamine composition comprising oligomeric amidoamine compounds in an amount of greater than 20 wt. % to 80 wt. % based on the weight of amidoamine composition, having the structure:
wherein each R′ is independently hydrogen or an alkyl group containing 1-5 carbon atoms provided that at least one R′ is hydrogen, preferably two R′ are hydrogen, most preferably all four R′ are hydrogen, R
2
is an aliphatic, cycloaliphatic, or aromatic residue of a primary amine compound having 2 to 24 carbon atoms and optionally containing non-reactive oxygen or at most an average of 4 secondary and/or tertiary nitrogen atoms in the backbone of the primary amine compound, and preferably R2 is an aliphatic moiety having from 2 to 8 carbon atoms, the average of x based on the amidoamine composition is at least 0.2, and Z comprises the residue of a polyoxyalkylene polyether polycarboxylic acid compound; wherein the amidoamine composition comprises the reaction product of primary polyamine compounds with polyoxyalkylene polyether polycarboxylic acid compounds at a corresponding equivalent weight ratio of at least 4.0:1.
In another embodiment of the invention, there is provided an epoxy functional surfactant comprising the reaction product of:
i) an amidoamine composition comprising oligomeric amidoamine compounds having the structure:
wherein each R′ is independently hydrogen or an alkyl group containing 1-6 carbon atoms provided that at least one R′ is hydrogen, preferably two R′ are hydrogen, most preferably all four R′ are hydrogen, wherein R
2
is an aliphatic, cycloaliphatic, or aromatic residue of a primary amine compound having 2 to 24 carbon atoms and optionally containing non-reactive oxygen or at most an average of 4 secondary and/or tertiary nitrogen atoms in the backbone of the primary amine compound, and preferably R
2
is an aliphatic moiety having from 2 to 8 carbon atoms, the average of x based on the amidoamine composition is at least 0.2, and Z comprises the residue of a polyoxyalkylene polyether polycarboxylic acid compound; with
ii) at least one epoxy resin having a functionality of from greater than 0.8 epoxide group per molecule at an equivalent weight ratio of the epoxy resin to the amidoamine composition of at least 2:1;
wherein the amidoamine composition comprises the reaction product of primary polyamine compounds with polyoxyalkylene polyether polycarboxylic acid compounds at a corresponding equivalent weight ratio of at least 4.0:1 under oligomeric reaction conditions effective to increase the amine nitrogen equivalent weight of the amidoamine composition by at least 10% over the average acid equivalent weight of the polyoxyalkylene polyether polyacid composition.
In another embodiment of the invention, there is an epoxy functional surfactant comprising the reaction product of:
i) an amidoamine composition comprising oligomeric amidoamine compounds in an amount of at least 20 wt. % to 80 wt. % based on the weight of amidoamine composition, said oligomeric amidoamine compounds having the structure:
wherein each R′ is independently hydrogen or an alkyl group containing 1-6 carbon atoms provided that at least one R′ is hydrogen, preferably two R′ are hydrogen, most preferably all four R′ are hydrogen, wherein R
2
is an aliphatic, cycloaliphatic, or aromatic residue of a primary amine compound having 2 to 24 carbon atoms and optionally containing non-reactive oxygen or at most an average of 4 secondary and/or tertiary nitrogen atoms in the backbone of the primary amine compound, and preferably R
2
is an aliphatic moiety having from 2 to 8 carbon atoms, the average of x based on the amidoamine composition is at least 0.2, and Z comprises the residue of a polyoxyalkylene polyether polycarboxylic acid compound; with
ii) at least one epoxy resin having a functionality of from greater than 0.8 epoxide group per molecule at an equivalent weight ratio of the epoxy resin to the amidoamine composition of at least 2:1;
wherein the amidoamine composition comprises the reaction product of primary polyamine compounds with polyoxyalkylene polyether polycarboxylic acid compounds at a corresponding equivalent weight ratio of at least 4.0:1.
In a further embodiment of the invention, there is provided an aqueous dispersion of an epoxy resin comprising combining:
a) water;
b) at least one epoxy resin having a functionality of greater than 0.8 epoxide group per molecule; and
c) at least one epoxy-functional surfactant comprising reacting
i) an amidoamine composition comprising oligomeric amidoamine compounds having the
Back Gayle Edward
Corley Larry Steven
Elmore Jimmy D.
Wang Pen-Chung
Aylward D.
Dawson Robert
Resolution Performance Products LLC
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