Specificadhesionmodelforbondinghot-meltpolyamidesto.PDFVIP

ELSEVIER International Journal of Adhesion Adhesives 24 (2004) 415-422 /locate/ijadhadh Specific adhesion model for bonding hot-melt polyamides to vinyl Charles R. Frihart* USDA Forest Service, Forest Products Laboratory, One Gifford Pinchot Drive, Madison, WI53726, USA Accepted 29 November 2003 Abstract Hot -melt polyamides a r e an important market for the dimer acid made from the tall oil fatty acids liberated during the Kraft pulping process. These polyamides bond well t o m a n y substrates, but n o t t o polyvinyl chloride (PVC), commonly called vinyl. Dimer -based polyamides m a d e f r o m secondary amines such as piperazine bond well t o vinyl. No model for this unique adhesion has been proposed even though m a n y commercial adhesives a n d other patents have utilized this feature of dimer -based polyamides. This paper examines the validity of models based on mechanical interlock, rheological properties, solubility parameters, a n d acid -base interactions. Available d a t a a r e consistent with the acid -base model, which depends on the availability of tertiary amides m a d e from secondary amine t o bond t o the vinyl hydrogen i n contrast t o the strong internal polyamide hydrogen bonding of secondary amides m a d e from primary amines. Poly(ester -amides) with a similar proton acceptor ability also b o n d t o vinyl. Published by Elsevier Ltd. Keywords: Polyamide; Hot-melt; Adhesive; Polyvinyl chloride; Model; Adhesion; Rheology; Solubility parameter: Acid-base; Poly(ester-amide); Hydrogen bond: Piperaz