Abstract
Polyurethane pressure-sensitive adhesives as raw materials for the manufacturing of protective films The present paper relates to water-borne polyurethane pressure-sensitive adhesives (PU-PSA) systems for self-adhesive protective films, and methods of their preparation. The typical protective films are self-adhesive films with excellent removability. Their manufacture is a film conversion process using common materials developed for the packaging industry (PVC and polyolefins). The most often used carrier for the constructions of protective films is PE. Polyurethane PSA layers are characterized by constant low peel adhesion between 3 and 5 N/2,5 cm.
Highlights
Protective films are packaging materials in a functional, rather than a legislative sense
The developed polyurethane pressure-sensitive adhesives were crosslinked with the following commercial multifunctional isocyanates: Basonate FDS 3425 (1,1`methylenebis(4-isocyanato-cyclohexane) from BASF), Basonate F 200 WD
Desmodur N 3200 at the levels of 1, 3, 5 and to 7 wt.% according to polyurethane polymer
Summary
Protective films are packaging materials in a functional, rather than a legislative sense. Polyurethane pressure-sensitive adhesive fulfil many of the industry's most severe requirements in terms of performance, environment and easy of practical application They have been widely used in self-adhesives, sealants and electrical products owing to their low glass transition temperature (Tg) between -40 and -60°C, hydrophobicity, acid-based resistance and excellent dielectric properties[5]. The high solid aqueous PU-PSAs are specified as the high viscosity PU-PSA water dispersions (Fig. 3) Their practical acceptable viscosity allows their direct coating on the dehesive carrier without the addition of the usually wetting and thickening agents. The aqueous PU-PSA dispersion, the formulation containing 2.0 wt.% DMPA, 20.0 wt.% Voranol 1010, 5.0 wt.% HTPB, 7.0 wt.% IPDI, 0.4 wt.% DBTL, 1.0 wt.% TEA, 60 wt.% distilled water, 0.2 wt.% EDA and 4.4 wt.% emulsifier Dowfax, was selected as raw material for protective films. The exact details can be found in AFERA 4001 (peel adhesion-the measure for removability), AFERA 4012 (shear strength) and AFERA 4015 (tack)
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