EPOXY ADHESIVE COMPOSITIONS COMPRISING AN ADHESION PROMOTER
Curable adhesive compositions comprising i. a curable epoxy resin ii. an amine curing agent, iii. a polymeric toughening agent, iv. a filler and v. a phosphoric acid ester according to the formula as an adhesion promoter, wherein R represents an aliphatic or aromatic residue that contains one or more carboxylic acid ester units and/or one or more urethane units and that further contains at least one ether group and n represents an integer of 1 or 2, methods of making them, bonded articles and methods for bonding.
1 . A curable epoxy adhesive composition comprising
vi. a curable epoxy resin
vii. an amine curing agent,
viii. a polymeric toughening agent,
ix. a filler material and
x. a phosphoric acid ester according to the formula
wherein R represents an aliphatic or aromatic residue that contains one or more carboxylic acid ester units and/or one or more urethane units and that further contains at least one ether group and n represents an integer of 1 or 2.
2 . The composition according to claim 1 wherein the group R of the phosphoric acid ester has a molecular weight between 200 and 10,000.
3 . The composition according to claim 1 wherein the curable epoxy resin comprises one or more aromatic glycidyl ether units.
4 . The composition according to claim 1 wherein the epoxy resin has a molecular weight of from 150 to 4,000 g/mole.
5 . The composition according to any claim 1 wherein the epoxy resin has a functionality of from 1 to 3.8
6 . The composition according to claim 1 wherein the filler material comprises glass particles.
7 . The composition according to claim 1 wherein the amine curing agent comprises a polyamido amine.
8 . The composition according to claim 1 wherein the polymer toughening agent comprises a core shell polymer.
9 . The composition according to claim 1 wherein the composition comprises a liquid polymer comprising repeating units derived from butadiene.
10 . The composition according to claim 1 further comprising a fire-retardant system that includes a mixture of:
(a) at least one compound selected from the group comprising alkaline earth metal hydroxides and aluminium group hydroxides, and
(b) at least one phosphorous-containing material.
11 . An article comprising a first substrate, a second substrate and a composition between the first and second substrate bonding the first substrate to the second substrate, said composition comprising the reaction product of a curing reaction of the curable epoxy adhesive composition according to claim 1 and wherein the first and second substrates are selected independently from each other from aluminium, steel and a resin-based composite material.
12 . A method for bonding a first substrate to a second substrate comprising
(i) adding the curable epoxy adhesive composition according to claim 1 to at least a part of the first substrate
(ii) applying the second substrate to the first substrate at a position where the first substrate contains the curable composition
(iv) subjecting the curable epoxy adhesive composition to curing, wherein the first and second substrate are selected independently from each other from aluminium, steel and a resin-based composite material.
13 . The method according to claim 12 wherein the curable epoxy adhesive composition is applied directly to the surface or the first or the second surface or is directly applied to the first and the second surface.
14 . The method according to claim 12 wherein the curing is carried out at room temperature.
15 . Use of a phosphoric acid ester according to the formula.
wherein R represents an aliphatic, cycloaliphatic and/or aromatic group, having at least one ether oxygen atom and at least one carboxylic acid ester and/or at least one urethane group and n is an integer of 1 or 2, as an adhesion promoting agent for bonding substrates with curable epoxy adhesive compositions wherein the substrates are selected from steel, aluminium and resin-based composite materials.