Thermoplastic Polyurethane with a Percisely Controlled Biodegradation Rate

Title: PROCESS FOR MAKING BIODEGRADABLE AND/OR BIOABSORBABLE POLYMERS

 Number/Link: WO2014/004334

Applicant/Assignee: Lubrizol

Publication date: 03-01-2014

Gist”: Two sets of parameters are given (and claimed) which, when iteratively adjusted, allow to independently modify the mechanical properties and biodegradation rate of a TPU.

Why it is interesting: Many biomedical materials for implants such as screws, bone plates, tissue scaffolds, pins etc need high mechanical properties but also a controlled biodegradation rate which can vary from weeks to years.  According to this case the precise control of the degradation rate is not possible with currently available bio-polymers.  The invention claims two sets of parameters one which controls the physical properties of a TPU like the molecular weight, harblock content, crystallinity etc, and another set which controls the biodegradation rate like the amount of ‘hydrolyzable units’ in the backbone, hydrophilicity ect. It is claimed that both mechanical properties and degradation rate can be independently controlled by adjusting one or more parameters of each set. In the examples TPUs are prepared from HMDI, 1,4-butane diol and poly(lactide-co-caprolactone) diols where the lactide is the hydrolyzable unit.

A poly(lactide-co-caprolactone)

A poly(lactide-co-caprolactone)

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

Can NOPs Rejuvenate Hot Cure Moulding?

Title: POLYOLS SUITABLE FOR HOT MOLDED FOAM PRODUCTION WITH HIGH RENEWABLE RESOURCE CONTENT

 Number/Link: US2013/210951

Applicant/Assignee: Bayer

Publication date: 15-08-2013 (priority PCT)

Gist”: Castor oil based polyols designed for hot cure flexible foam allow for higher renewable content.

Why it is interesting: In the recent years there has been a growing use of renewable-resource based polyols in flexible foam production. However, because the current moulded flexible foam industry is dominated by the so-called “cold cure” process which typically needs highly reactive polyols, the maximum amount of renewables is usually limited to about 10% of the polyol. Bayer have now developed a natural oil based polyol specifically for hot cure moulding. The polyol of the invention is based on castor oil, EO, PO and a DMC catalyst such that the total amount of EO is 20 to 30% and the total amount of primary OH is between 35-45%.  When used in a hot cure moulding process the polyol allows for at least 30% (on the polyol) of renewables with foams having properties similar to conventional hot cure foams.

Major Component of Castor Oil

Major Component of Castor Oil

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