Epoxy-amino coatings

By far the most important coatings that make use of liquid amino-containing dimer polyamides and fatty amido amines are what is referred to as epoxy-polyamide coatings. These coatings are used widely as maintenance paints. 

Epoxy resin coatings are cured by copolymerization with acrylic, polysulfide, polyurethane, polyamine, polyamide, amino, and phenolic oligomers. 

The can and coil coatings, generally, are cross-linked with phenol, melamine, or urea-formaldehyde condensation products at elevated temperatures (150-200°C) with acid catalysts. Normal epoxy-amino resin weight ratios are epoxy-urea, 70 30 epoxy-benzoguanamine, 70 30 epoxy-melamine, 80 20, and 90 10. Increasing cross-linker levels give improved thermal and chemical resistance at the sacrifice of coating flexibility and adhesion. 

A number of plastic, adhesive, and coating materials are utilized in a densely cross-linked form known as thermosets. Some of the more important of these include the phenol-formaldehyde resins, urea-formaldehydes, polyimides, epoxies, amino resins, and the alkyds, among others (8). Because these... 

Epoxy-amino resin finishes are used widely as can coatings appliance primers clear coatings for brass, hardware, jewelry and vacuum metallized plastics foil coatings and coatings for hospital and laboratory furniture. 

Heat-reactive resins are more compatible than oil-soluble resins with other polar-coating resins, such as amino, epoxy, and poly(vinyl butyral). They are used in interior-can and dmm linings, metal primers, and pipe coatings. The coatings have excellent resistance to solvents, acids, and salts. They can be used over a wide range of temperatures, up to 370°C for short periods of dry heat, and continuously at 150°C. Strong alkaUes should be avoided. 

Cured amino resins are far too brittle to be used alone as surface coatings for metal or wood substrates, but in combination with other film formers (alkyds, polyesters, acryUcs, epoxies) a wide range of acceptable performance properties can be achieved. These combination binder coating formulations cure rapidly at slightly elevated temperatures, making them well suited for industrial baking appHcations. The amino resin content in the formulation is typically in the range of 10—50% of the total binder soHds. 

A waterborne system for container coatings was developed based on a graft copolymerization of an advanced epoxy resin and an acryHc (52). The acryhc-vinyl monomers are grafted onto preformed epoxy resins in the presence of a free-radical initiator grafting occurs mainly at the methylene group of the aHphatic backbone on the epoxy resin. The polymeric product is a mixture of methacrylic acid—styrene copolymer, soHd epoxy resin, and graft copolymer of the unsaturated monomers onto the epoxy resin backbone. It is dispersible in water upon neutralization with an amine before cure with an amino—formaldehyde resin. 

Borazines, particularly polymeric compounds, have been extensively investigated as preceramic materials from which coatings and fibers of boron nitride can be produced upon thermolysis. B-aryl and halogeno-amino borazines are reported to have use as fire retardants in cotton and nylon textiles. Other reported uses for borazines are as epoxy resin catalysts, polymerization inhibitors of unsaturated alcohols and esters, and catalysts for polymerization of alkenes (95). 

An evaluation was conducted to identify the benefits that might accrue when ZAs were used in high solid polyesters, high solid epoxies, and conventional alkyds, in each instance the coating being applied to two or more different surfaces. Recognizing that alkyds and polyesters are both characterized by available carboxy and hydroxy groups, the decision was made to evaluate amino and carboxy ZAs in these systems (Table 3). 

Both aqueous polymer-based systems (latex), made by emulsion or dispersion polymerization, and oil-modified alkyd resin-based systems are still in wide use [781], Table 12.2 shows the composition of a typical water-based emulsion paint. There is a wide variety of coatings, ranging from broad applicability to highly specialized, including latexes, amino resins, isocyanates, epoxy resins, acrylic resins, polyester... 

The traditional cross-linking technologies utilized in the coatings market range from hydroxyl functional binders (acrylics or polyesters) cross-linked with melamines (IK) or isocyanates (2K) to drying oils that cure through oxidation of unsaturation in the backbone, to epoxy resins cross-linked with amino resins (amido amines, amines, etc.). 

The thermoset acrylics (20) of major importance in the coating industry, in recent years, have been developed primarily by Canadian Industry Ltd. and by Pittsburgh Plate Glass Co. in this country (4). Raw materials are acrylamide, acrylic acid, acrylates, and styrene. Cross-linking agents are amino and epoxy resins. The materials are also self-cross-linking. They are usually sold as solutions in paint solvents. 

Silanes used for treatment dimethyldiethoxy silane, 3-(methacryloxy) propyltrimethoxy silane, vinyl triethoxy silane, amino silane. Silane coating was estimated to be 0.2 wt%. Treatment with epoxy silane has been used followed by PS-maleic anhydride grafting through amine spacer. 

The polyester resin used in this study, MR 13006 (Aristech Corporation), was supplied as a 60-wt% solution in styrene monomer. The epoxy resin, a digly-cidyl ether of bisphenol A (Epon 828), was obtained from Shell Chemical Company. The reactive liquid rubber, an amino-terminated butadiene-acrylonitrile copolymer (ATBN 1300 x 16), was provided by the BFGoodrich Company. The resin was mixed with additional styrene monomer to maintain the ratio of reactive unsaturation in the polyester-to-styrene monomer at 1 to 3. We added 1.5 wt% of tert-butylperbenzoate initiator to the solution, which we then degassed under vacuum. The mixture was poured between vertical, Teflon-coated, aluminum plates and cured under atmospheric pressure at 100 °C. In the modified compositions, the rubber was first dissolved in the styrene monomer, and then all the other components were added and the solution cured as described. In all the compositions, the ratio of the amine functions with respect to the epoxy functions was kept at 1 to ensure complete cure of the epoxy. 

CCRIS 6680 Cyclohexanemethanamine, 5-amino-1,3,3-trimethyl- EINECS 220-666-8 HSDB 4058 Isophorone diamine UN2289 Vestamin TMD. Epoxy curative for flexible coatings, adhesives, castings and composites. Degussa-Hiils Corp. 

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