Two-part epoxy composition
A two-part epoxy composition is provided that comprises a first part having a mixture of an epoxy resin and an anhydride, and a second part having a curing agent. Also provided is a method for making a substantially bis-∝-glycol free epoxy resin for two-part epoxy compositions, and a method for applying a two-part epoxy composition to a system of water piping.
1. A two-part epoxy composition comprising a first part comprising about 95-99.9% by weight of an epoxy resin and about 0.1-5% by weight of an anhydride, said anhydride being capable of reacting to said epoxy resin at about room temperature so said first part is substantially bis-∝-glycol free, having a bis-α-glycol concentration of less than 10 ppm, and a second part comprising a curing agent, wherein said two-part epoxy composition is capable of curing at a temperature of up to about 40° C.
2. The two-part epoxy composition of claim 1 , wherein said epoxy resin is a diglycidyl ether of a dihydric phenol.
3. The two-part epoxy composition of claim 2 , wherein said dihydric phenol is bisphenol A.
4. The two-part epoxy composition of claim 1 , wherein said anhydride is methylhexahydrophthalic anhydride.
5. The two-part epoxy composition of claim 1 , wherein said curing agent is selected from the group consisting of amines, cycloaliphatic amines, amine adducts, mercaptans, polyamides, and amido-amines.
6. The two-part epoxy composition of claim 1 , wherein said curing is capable of occurring at about room temperature.
7. The two-part epoxy composition of claim 1 , further comprising an additive wherein said additive is selected from the group consisting of pigments, thixotropic agents, defoamers, mineral fillers, leveling agents, antifoam, wetting agents, and diluents.
8. The two-part epoxy composition of claim 7 , wherein said second part comprises said curing agent about 40-50% by weight, said mineral fillers from about 45% to about 55% by weight, and other additives up to about 5% by weight.
9. The two-part epoxy composition of claim 1 , wherein the first part to said second part ratio is about 1:1 to about 10:1 by weight.
10. The two-part epoxy composition of claim 1 , wherein the first part has no more than about 10 parts per million bis-∝-glycol.
11. A process for coating a system of water piping comprising the steps of:
a) mixing a first part comprising an epoxy resin and about 0.1-8% by weight of an anhydride, and a second part comprising a curing agent to form a two-part epoxy composition, said first part being reacted at about room temperature so that it is substantially bis-α-glycol free, having a bis-α-glycol concentration of less than 10 ppm;
b) coating said system with said composition; and
c) curing said composition at up to about 40° C.
12. The process of claim 11 , wherein said epoxy resin is a diglycidyl ether of a dihydric phenol.
13. The process of claim 12 , wherein said dihydric phenol is bisphenol A.
14. The process of claim 11 , wherein said anhydride is methyl methylhexahydrophthalic anhydride.
15. The process of claim 11 , further comprising the step of heating said composition after coating said system.
16. The process of claim 15 , wherein said curing step is at about room temperature.
17. A process for making an epoxy resin substantially bis-∝-glycol free for two-part epoxy compositions comprising the steps of:
c) mixing an epoxy resin and about 0.1-8% by weight of an anhydride at room temperature to form a mixture; and
d) reacting said mixture at about room temperature until said mixture is substantially free of bis-∝-glycol, having a bis-α-glycol concentration of less than 10 ppm.
18. The process of claim 17 , wherein said epoxy resin is a diglycidyl ether of a dihydric phenol.
19. The process of claim 18 , wherein said dihydric phenol is bisphenol-A.
20. The process of claim 17 , wherein said anhydride is methylhexahydrophtalic anhydride.
21. The process of claim 17 , wherein an additive is further included in said mixing step.
22. The process of claim 21 , wherein said additive is selected from the group consisting of pigments, thixotropic agents, defoamers, mineral fillers, leveling agents, antifoam, wetting agents, and diluents.
23. The process of claim 17 , further comprising the step of applying heat of up to about 40° C. to cure said mixture.