Epoxy resin curing agent of epoxy resin-liquid amine adduct and polyamidoamine
View Patent ↗This invention describes epoxy-amine compositions that have low mix viscosity and a fast drying property at temperatures below freezing. The composition is useful for high solids coating applications, for adhesive and membrane applications, and for preparing impregnated substrates.
1. A low viscosity curing agent composition for low temperature cure of epoxy resin compositions comprising a blend of: (a)(i) an amine adduct of an epoxy resin having at least 1.5 epoxy groups per molecule and (a)(ii) a liquid amine and (b) a liquid polyamidoamine prepared by reacting a long-chain carboxylic acid and an amine wherein the polyamidoamine is further reacted with an epoxy functional resin and a monoglycidyl ether or ester;
wherein the liquid amine is selected from the group consisting of cycloaliphatic, aliphatic and alkylaromatic polyamines.
2. The low viscosity curing composition of claim 1 , wherein the liquid amine used for reaction product (a) is selected from the group consisting of cycloaliphatic amines, aliphatic amines and alkylaromatic amines, having a hydrocarbyl backbone containing from 2 to 20 carbon atoms.
3. The low viscosity curing composition of claim 2 wherein the liquid amine used for reaction product (a) is a cycloaliphatic or aliphatic diamine containing from 6 to 16 carbon atoms and having either two primary amino groups or one primary and one secondary amino group.
4. The curing agent composition according to claim 3 , wherein the liquid amine is a mixture of amines wherein one amine comprises two primary amino groups and wherein another amine comprises one primary and one secondary amino group.
5. The curing agent composition according to claim 1 , wherein the curing agent is prepared in-situ from:
a) an amine, selected from the group consisting of cycloaliphatic amines, aliphatic amines and alkylaromatic amines having a hydrocarbyl backbone containing from 2 to 20 carbon atoms;
b) a substituted alkyl amidopolyamide prepared from a) and a long-chain monocarboxylic acid having from 6 to 50 carbon atoms, or a long-chain dicarboxylic acid having from 18 to 60 carbon atoms;
c) an epoxy resin derived from polyglycidyl ethers of polyhydric phenols; and
d) a mono functional epoxy ether or ester, linear or branched having from 4 to 36 carbon atoms.
6. A formulation to be used at low temperature containing the curing agent of claim 1 , an accelerator compatible with the curing agent derived from mineral or organic acids or salts, from phenol derivatives or a combination thereof, and an epoxy compatible accelerator derived from a product containing an acrylic ester group wherein the acrylic functionality is more than two.
7. The formulation of claim 6 , wherein the epoxy compatible accelerator comprises a blend of polyacrylate and an epoxy resin having a 1,2-epoxy equivalency greater than one epoxy group per molecule wherein the epoxy resin is saturated or unsaturated, linear or branched, aliphatic, cycloaliphatic, aromatic or heterocylic, and optionally has substituents which do not materially interfere with the curing reaction.
8. The formulation of claim 6 , wherein the epoxy compatible accelerator is an acrylic ester derived from an aryl.
9. A cured coating film comprising the formulation of claim 7 wherein the film is applied on a shaped carrier.
10. The cured coating film according to claim 9 wherein the shaped carrier is comprised of wood or polymers.