Desmocolls, adhesives

Desmocoll 176, 400 and 420 are primarily linear thermoplastic polyurethane elastomer resins of medium, medium-high and high crystallization rates, respectively. They are supplied as small, light brown, talc-covered, pieces. The polymers have a density of 1 2-1-23 g cm . This density, and their stabilization by the hydrolysis stabilizer Staboxal PCD, imply that they are poly(ester-urethanes). They show outstanding adhesion to numerous materials including plastics, rubber, leather, fabrics, wood, metals, etc. 

The following solvents dissolve some if not all of the foregoing Desmocoll adhesive polymers methyl, ethyl and butyl acetates, acetone, methyl ethyl ketone, methylene chloride, propylene dichloride, trichlor-ethylene, the monomethyl ether acetates of ethylene glycol and 1,3-butylene glycol, etc. Toluene may be used as a dilution solvent. 

In bonding strong substrates, and if solvent and greater heat resistance are required in the adhesive bond, then the Desmocolls may be mixed with appropriate amounts of isocyanates such as TDI,4,4, 4"-triphenylmethane triisocyanate (Desmodur R) or Desmodur RF (Fig. 8.7), which is thiophosphoric acid (p-isocyanatophenyl ester) used as a 20% solution in methylene chloride. 

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