The Effect of Alpha Hydroxy Acids on the Tack of Pressure-sensitive Adhesive

The adhesion and tackiness of cosmetic patches are very important factors, especially when the patches are applied to an area with sensitive skin, such as face. The objective of this work is to study the influence of varieties of alpha hydroxy acids concentration as ingredients of cosmetic patches on their tackiness. Different amounts of two cosmetic patch ingredients, glycolic acid(GA) and lactic acid(LA), were mixed thoroughly with solution of a acrylic pressure-sensitive adhesive(PSA). Films with 32 μm thickness were prepared by casting formulations on a polyethylene terephthalate film. Tack test was carried out on different formulations according to ASTM D3121-94. It was observed that tack value increases by increasing LA concentration up to 6 % (w/w). Tack value increase by increasing GA concentration up to 1 % (w/w), then it decreases by increasing GA concentration up to 3 % (w/w), and then increases again by increasing GA concentration above 6 % (w/w). These results are due to changes in entanglements, glass transition temperature, plateau modulus Go of adhesive, and functional groups that exist in additives.