Process for the preparation of flexible epoxy resin systems

Abstract

A flexible epoxy resin system is prepared by incorporating a combination of hardeners (A) and (B) in an epoxy resin, wherein the amounts of the two hardeners are varied to adjust the flexibility of the epoxy resin.

Description

Claims

1. A process for preparing a flexible epoxy resin system, comprising:

mixing with an epoxy resin a hardener composition comprising a combination of:

Hardener (A) which has an NH-active equivalent weight of 100-300 and is prepared by mixing (i) a diamine containing polyether groups and urethane groups (PEDA) of the following composition: ##STR1## wherein R is ##STR2## R.sup.1 is a (cyclo)alkylene radical which has 4-14 carbon atoms, and is optionally substituted by 1-4 CH.sub.3 groups, or units of the formula I or II ##STR3## wherein R.sup.2 is an alkylene radical which has 6-20 carbon atoms, optionally substituted by 1-4 CH.sub.3 groups, wherein 1-3 --CH.sub.2 -- groups can be replaced by --O-- or --NCH.sub.3 -- groups, and (ii) a diamine of the formula:

H.sub.2 --R.sup.3 --NH.sub.2 (DA)

where

R.sup.3 is a (cyclo)alkylene radical which has 2-15 C atoms, optionally substituted by 1-4 CH.sub.3 groups, or units of the formula I or II ##STR4## Hardener (B) which has the same NH-active equivalent weight as Hardener (A) of 100-300, and is prepared by mixing the (i) diamine (PEDA) containing polyether groups and urethane groups and (ii) a monoamine of the composition:

H.sub.2 N--R.sup.4

where

R.sup.4 is an optionally alkyl-substituted alkyl radical having 6-20 C atoms, where 1-3 --CH.sub.2 -- groups can be replaced by --O-- or --NCH.sub.3 -- groups; the weight ratio of hardeners (A) and (B) ranging from 1:99 to 99:1.

2. The process of claim 1, wherein said diamine (ii) is selected from the group consisting of ethylenediamine, 2-methylpentamethylenediamine, 2,2,4-(2,4,4)-trimethylhexamethylenediamine, 3-(Cyclohexylamino)propylamine, 3,3'-Dimethyl-4,4'-diaminodicyclohexylmethane, m-xylylenediamine, 1,2-diaminocyclohexane and isophoronediamine.

3. The process of claim 1, wherein said Hardener (A) has an NH-active equivalent weight of 190.

4. The process of claim 1, wherein monoamine (ii) is a member selected from the group consisting of hexylamine, 2-ethylhexylamine, decylamine, dodecylamine, tridecylamine, butoxypropylamine, hexoxyproylamine, 3-(2-ethylhexoxy)propylamine, lauryloxypropylamine, diethylaminopropylamine and 1-diethyl-amino-4-aminopentane.

5. The process of claim 1, wherein the epoxy resin is based on bisphenol A and bisphenol F.

6. The process of claim 4, wherein said monoamine is selected from the group consisting of hexoxypropylamine, 3-(2-ethylhexoxy)propylamine and lauryloxypropylamine.

7. The process of claim 1, wherein the epoxy resin-hardener composition further contains up to 4% by weight of a catalyst which catalyzes the NH/epoxide reaction.