Epoxy resins of controlled conversion and a process for their preparation
First Claim
1. An epoxy resin comprising the reaction product of a polyepoxide and a polyol wherein the reaction product contains both epoxy groups and terminal phenolic hydroxyl groups in an amount of at least about 0.25 weight percent of each of the epoxy groups and the terminal phenolic hydroxyl groups, said weight percent being based on the total weight of the epoxy resin reaction product, and which reaction product exhibits an essentially constant viscosity over time.
2 Assignments
0 Petitions
Accused Products
Abstract
Epoxy resins containing both terminal hydroxyl groups and epoxy or epoxy-derived groups are prepared by advancing a polyepoxide with a polyol and terminating the reaction at a point such that the epoxy resin reaction product contains both epoxy and terminal hydroxyl groups. The controlled conversion resins have improved cure rates. The epoxy groups can be further reacted to form epoxy-derived groups to improve the cure rate even further. The epoxy resins exhibit lower melt and solution viscosities than those exhibited by conventional epoxy resins having the same epoxy equivalent weight, as well as curing quickly when used. The resins are usefully employed at high solids levels in can coating formulations and other epoxy formulations wherein the resin is applied from an organic liquid solution or aqueous dispersion.
21 Citations
24 Claims
- 1. An epoxy resin comprising the reaction product of a polyepoxide and a polyol wherein the reaction product contains both epoxy groups and terminal phenolic hydroxyl groups in an amount of at least about 0.25 weight percent of each of the epoxy groups and the terminal phenolic hydroxyl groups, said weight percent being based on the total weight of the epoxy resin reaction product, and which reaction product exhibits an essentially constant viscosity over time.
- 4. A process for preparing an epoxy resin which method comprises reacting a polyepoxide with a polyhydric phenol in the presence of a catalyst for the reaction of an epoxy group with a hydroxyl group and terminating the reaction at a point when the reaction product contains at least about 0.25 weight percent of each of the epoxy groups and the terminal hydroxyl groups, said weight percent being based on the total weight of the epoxy resin reaction product
-
16. An epoxy resin comprising the reaction product of a polyepoxide and a polyol wherein the reaction product contains
(a) terminal phenolic hydroxyl groups in an amount of at least about 0.15 equivalents per kilogram resin (eq/kg), (b) groups derived from epoxy groups, and optionally (c) epoxy groups the total amount of groups (b), and, if present (c) in the resin being at least about 0.05 equivalents, per kilogram of resin.
- 20. A process for preparing an epoxy resin which method comprises reacting a polyepoxide with a polyol in the presence of a catalyst for the reaction of an epoxy group with a hydroxyl group and terminating the reaction at a point when the reaction product contains at least about 0.05 equivalents epoxy groups per kilogram of resin and about 0.15 equivalents terminal phenolic hydroxyl groups per kilogram of resin, then reacting at least a portion of the epoxy groups to form epoxy-derived groups.
Specification