Polyamide resin for untreated HDPE inks
A controlled trial for polyamide ink resin on untreated HDPE or LDPE using production film, the finished ink and a defined adhesion method.
A polyamide resin for untreated HDPE inks cannot be assessed apart from the film and the finished ink. Film grade, surface condition, solvent balance, pigment package, drying and the adhesion method can all change the result.
Unimide US 77 is intended for trials in inks printed on untreated HDPE and LDPE. Adhesion must be tested with the production film, full formulation and intended press conditions.
Substrate condition
Record the polymer, film grade, supplier, print side and storage conditions. If surface energy is measured, record the value, instrument and method. Use production film because nominally similar HDPE or LDPE grades can differ in additives and surface condition.
Production ink system
Evaluate the resin with the actual solvent blend, pigment, additives and any modifying resin. Check solution quality and ink stability at the target press viscosity before running the print and drying trial.
Adhesion test
Define conditioning time, tape type, peel direction, peel rate and the pass criterion before comparing formulations. Record the printed film, test conditions and result. If the film will be laminated or heat sealed, include that operation in the test programme.
Surface treatment
Binder selection does not remove the need to assess surface treatment. If untreated-film adhesion varies by film lot or operating condition, compare the untreated result with the plant's normal treatment process before setting a production specification.
Candidate polyamide grades
The polyamide resin grades for printing inks differ in solubility, softening point, amine and acid value, and supplied viscosity. Grade selection also depends on the solvent system, substrate and finished-film requirements.
Discuss an untreated-film ink trial with our technical team.