This action was focused on the substitution of commercially available hardener for water-based epoxy resins, such as polyamines and polyammido-amines, with IA-based hardener developed in the technical action B2 as ligands for the flexible abrasive tapes.
The substitution of a commercially available hardener for water-based epoxy resins, such as polyamines and polyamidoamines, with an IA-based hardener, was developed by applying the crosslinking agents delivered in the technical action B2.
This composition can avoid the use of phenol-formaldehyde resins which are responsible of the dangerous emissions during the curing process having a detrimental effect on the environment and on the human health. The aim of this technical action was to maintain unchanged the production facilities at Imperial, but some chemical modifications had to be applied on the adhesive mixtures for the water-based epoxy resins. At the beginning many studies were dedicated to study the adapted composition of the IA-based hardener inducing a complete curing of a commercially available water-based epoxy resin. These studies were carried out with DSC technique simulating the production process for the flexible abrasive tapes.
The selected composition for the crosslinking agent mixture, constituted by 25% by wt of TMPTI and 15% by wt of MTHPA, was 40% by wt to obtain an efficient crosslinking reaction starting at 90°C for 1 h, as requested for the processing conditions at Imperial production facilities. The subsequent activity was the preparation at the APM lab of the crosslinking selected mixture (25 kg), constituted by MTHPA and TMPTI, to obtain some prototypes at the processing facilities at Imperial by using the above described experimental conditions.
The high viscosity of the reactive mixture was not able to form a homogenous the liquid coating on the paper substrate. The production of some meters of the flexible abrasive prototype were stopped and the trial was aborted.