Epoxy resin systems for composites
Compositions and methods for forming epoxy resin systems are provided. In one embodiment, a composition is provided for an epoxy resin system including a liquid epoxy resin component including a liquid epoxy resin and an acrylate monomer, a curing agent component including a compound having an imidazole group and, optionally, a co-curing agent for the compound having an imidazole group comprising a phenolic monomer compound, a branched chain carboxylic acid, and combinations thereof, and a non-aromatic polyol compound. The composition may be used to form composites, such as used in commercial wind turbine blade manufacturing.
1. An epoxy resin system, the epoxy resin system consisting essentially of:
a liquid epoxy resin component comprising:
a liquid epoxy resin; and
an acrylate monomer;
a curing agent component consisting essentially of:
a compound having an imidazole group; and
optionally, a co-curing agent for the compound having the imidazole group comprising a phenolic monomer compound, a branched chain carboxylic acid, or a combination thereof; and
a non-aromatic polyol compound, wherein the epoxy resin system is free of a radical initiator, wherein the non-aromatic polyol compound optionally comprises part of the epoxy resin component, optionally comprises part of the curing agent component, optionally comprises part of the epoxy resin system with the liquid epoxy resin component and the curing agent component, or a combination thereof.
2. The epoxy resin system of claim 1 , wherein the liquid epoxy resin component comprises an aromatic or a non-aromatic epoxy resin based on bisphenol A, bisphenol F, phenolic novolacs, hydrogenated bisphenol A, non-aromatic diols, or a combination thereof.
3. The epoxy resin system of claim 1 , wherein the liquid epoxy resin component comprises:
from 50 to 99 parts of liquid epoxy resin; and
from 1 to 50 parts of the acrylate ester of a mono-ol or polyol, the methacrylate ester of a mono-ol or polyol, or a combination thereof.
4. The epoxy resin system of claim 1 , wherein the acrylate monomer comprises an acrylate ester of a mono-ol or polyol, the methacrylate ester of a mono-ol or polyol, or a combination thereof.
5. The epoxy resin system of claim 1 , wherein the compound having an imidazole group is a compound selected from the group consisting of imidazole, 1-methylimidazole, 2-methylimidazole, 2-propylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, benzimidazole, toluimidazole, and combinations thereof.
6. The epoxy resin system of claim 1 , wherein the compound having an imidazole group is present in the amount of 1 to 15 parts based on a total of 100 parts of the liquid epoxy resin component.
7. The epoxy resin system of claim 1 , wherein the non-aromatic polyol compound comprises a number average molecular weight between about 1000 and 10000.
8. The epoxy resin system of claim 1 , wherein the non-aromatic polyol compound comprises a glycol selected from the group consisting of poly(ethylene oxide) glycol, poly(propylene oxide) glycol, poly(butylene oxide) glycol, polytetrahydrofuran glycols, poly(ethylene adipate) glycol, poly(propylene sebacate) glycol, poly(hexamethylene carbonate) glycol, silicone-alkylene oxide copolymer, poly(butadiene-co-acrylonitrile) glycol, and combinations thereof.
9. The epoxy resin system of claim 1 , wherein, if present, the phenolic monomer compound is selected from the group consisting of benzenediols, bisphenols, and combinations thereof.
10. The epoxy resin system of claim 1 , wherein, if present, the branched chain carboxylic acid has 5-40 carbon atoms.
11. The epoxy resin system of claim 1 , wherein the epoxy resin system is free of anhydride compounds, wherein the epoxy resin system is free of a core-shell rubber, or a combination thereof.
12. A composite prepared using the epoxy resin system of claim 1 .
13. The composite of claim 12 , wherein the composite is in the form of a windmill blade component.
14. A method for manufacturing a composite, comprising:
providing a reinforcing fiber substrate;
mixing the epoxy resin system of claim 1 ;
contacting the reinforcing fiber substrate with the epoxy resin system; and
curing the epoxy resin system to form the composite.
15. The method of claim 14 , wherein contacting the reinforcing fiber substrate with the epoxy resin system comprises a pultrusion process.
16. The method of claim 14 , wherein the non-aromatic polyol compound is provided with the liquid epoxy resin component, the curing agent component, or both.
17. The method of claim 14 , wherein the epoxy resin system is free of anhydride compounds, wherein the epoxy resin system is free of a core-shell rubber, or a combination thereof.