Patent Title: LATENT TWO-PART POLYURETHANE ADHESIVES CURABLE WITH INFRARED RADIATION

 Number/Link: WO2016/205251 and related cases: WO..5252, WO…5254 and WO..5255

Applicant/Assignee: Dow

Publication date: all published on 22 dec 2016

“Gist”: Two-component PU adhesive using 3 different delayed-action catalysts

Why it is interesting: Two component adhesive systems need a sufficiently long ‘open time’ preferably combined with a fast cure once activated, e.g. by heat. Heat curing using infrared radiation allows for ‘spot curing’ , i.e. curing only predetermined parts of the adhesive such that the assembly can be handled and can be cured completely in a subsequent step.  This process is fast and saves energy.  The current invention is about IR curable adhesives containing 3 different types of latent catalysts: a latent room temperature organometallic catalyst based on Sn, Zn or Bi added to the polyol component, a phenol-blocked cyclic amidine and a carboxylic acid blocked cyclic amidine.  The two latter catalysts can either be included in the polyol or in the isocyanate component. The catalysts used in the examples are dioctyltinthioglycolate, phenol blocked 1,8-diazabicycloundec-7-ene and a carboxilic acid blocked 1,8-diazabicycloundec-7-ene.

1,8-diazabicycloundec-7-ene