Polyurethane-Polyamides from Dimer Diacids

Title: A POLYOL BASED ON DIMER FATTY ACID RESIDUES AND THE CORRESPONDING POLYURETHANES

 Number/Link:WO2015/097433

Applicant/Assignee: Croda

Publication date: 2-07-2015

Gist”: Polyurethane/polyamide elastomers based on dimer diacids and long chain dicarboxylic acids

Why it is interesting: Polyurethane elastomers (and thermoplastic elastomers) based on dimer diacids or dimer diols are very hydrophobic and hydrolysis resistant but are relatively soft with lowish mechanical properties. According to this invention, using a blend of a dimer diacid (or -diol) and a (semi-) crystalline C17 to C32 dicarboxilic acid (or -diol) results in elastomers with greatly improved hardness and tensile strength while retaining flexibility and hydrolysis resistance. The C17 to C32 dicarboxylic acids can be prepared by a self-metathesis reaction of unsaturated fatty acid esters.  In the examples a C36 dimer diacid is used together with 1,18-octadodecanoic acid (prepared by metathesis from methyl oleate).  This is reacted ‘one shot’ with 4,4′ MDI and hexanediol or DEG, resulting in 85 shore A elastomers with high elongation and hydrolysis resistance.

A C36 dimer diacid

A C36 dimer diacid

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