Latent epoxy-amine composition for CIPP application

A two-component epoxy resin composition, consisting of:

• a resin component K1 comprising:
• between 75 and 95 wt.-%, based on component K1, of at least one epoxy resin A that contains on average more than one epoxy group per molecule;
• between 5 and 25 wt.-%, based on component K1, of at least one epoxy-functional reactive diluent RD having one or two epoxy groups per molecule;
• and
• a hardener component K2 comprising:
• between 50 and 70 wt.-%, based on component K2, of at least one amino-functional hardener B of formula (I),
• wherein n is an integer with a value of 2 or 3, R1 is a linear, cyclic or branched alkyl residue that optionally contains ether oxygen atoms and R2 is a methyl or ethyl group;
• between 15 and 25 wt.-%, based on component K2, of at least one Lewis base LB that is selected from the group consisting of tris-2,4-6-dimethylaminomethyl phenol, 1,1,3,3-tetramethylguanidine, and 1,8-diazabicyclo [5.4.0] undec-7-ene;
• and
• between 15 and 25 wt.-%, based on component K2, of at least one carboxylic acid AC,
• wherein the at least one Lewis base LB and the at least one carboxylic acid AC are present together in the form of a Lewis salt, and
• wherein a molar ratio of carboxylic acid groups of the at least one carboxylic acid AC to tertiary amino groups of the at least one Lewis base LB is between 0.6 and 0.95.