Synergism of the influence of phenol-formaldehyde resins and nitrogen-containing compounds on the adhesion properties of plastisol coatings

摘要

The improvemento to the adhesion strength of plastisol coatings caused by the addition of phenol-formaldehyde resins (PF resins) is due to a simultaneous increase in both the molecular and deformation components (refs. 1.2). However, PF resins only result in an improvement to the adhesion strength of PVC plastisols if the processing t emperature is increased to 200-230 deg C, which causes the thermal decomposition of the PVC. Under such conditions the contribution of the molecular component, or true adhesion, is not more than 30 % of the total adhesion strength (ref. 1). If the melting temperature of the coatings is reduced (for example to 170 deg C), the energetic interaction of the components of the PVC plastisols is poor (ref. 2 )resulting in a sharp drop in the adhesion strength and the contribution of true adhesion is zero. Consequently, interest has been shown in using modifiers capable of providing high levels of adhesion at temperatures of < 200 deg C in PVC plastisols in stead of PF resins.