Self-Healing Polyurethane Elastomers

Patent Title: POLYURETHANE

 Number/Link: W02016185172

Applicant/Assignee: Croda

Publication date: 24-11-2016

Gist”: PU from polyols which contain both a fatty dimer residue and an H-bonding group, show self-healing properties

Why it is interesting: Polyurethane elastomers with ‘intrinsic’ self-healing properties (i.e. without the need for external chemicals like encapsulated monomers) can be prepared by reacting isocyanates with polyols that have at least one urethane, amide or carbonate group and at least one fatty dimer residue. It is theorized that the fatty dimer allows the soft-phase of the polymer to flow and H-bonds to form, thus restoring most of the properties after damage.  In the examples polyols with internal urethane groups were prepared by reacting C36 dimer diol with HDI, which were then reacted with MDI and BDO. Samples of the resulting elastomers were cut in half, and manually stuck together again under mild heating (60°C), thus recovering most of their tensile and elongation properties.

A dimer diol

A dimer diol

Very Tough Polyurethane Elastomers Based on a Novel Type of Polyester Polyol

Title: POLYESTER POLYOL FOR USE IN POLYURETHANE

 Number/Link: WO2013/156450

Applicant/Assignee: Purac Biochem

Publication date: 24-10-2013

Gist”: Tough polyurethane elastomers can be prepared from polyester polyols based on dimer acid and lactide oligomers.

Why it is interesting: The invention claims a new type of ABA polyester polyol where A is a hydrophilic lactide oligomer and B is a hydrophobic dimer diacid initiator. The lactide ologimers can be produced by ring-opening polymerization of cyclic lactide and preferably contain between 4 and 16 lactoyl units.  The dimer diacid is prepared by dimerizing unsaturated C12 to C22 fatty acids, preferably linoleic or linolenic acid. The molecular weight of the polyester polyol is preferably between 1000 and 3500 dalton. Solid polyurethane elastomers prepared from this type of polyols reportedly have much improved toughness and other mechanical properties.

Example of a Dimer Acid

Example of a Dimer Acid

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