Polyurethane Elastomers containing Polyrotaxanes

Title: CAST-MOLDED HEAT-CURABLE POLYURETHANE ELASTOMER

 Number/Link:  WO2015/159875  (Japanese)

Applicant/Assignee: UBE

Publication date: 22-10-2015

Gist”: 1-10% of a polyrotaxane is incorporated in a hot cast PU elastomer system

Why it is interesting: Polyrotaxanes are molecular systems consisting of a linear polymer which is “threated” through a number of ring-shaped molecules. The rings are prevented from ‘sliding off’ by blocking-molecules at both ends of the “thread”. In this invention polyrotaxanes based on a polycaprolactone thread and cyclodextrin rings (pref.) are incorporated in hot cast elastomer systems in amounts of 1-10% (w/w). Because cyclodextrin rings contain hydroxyl groups they react with the isocyanate incorporating the polyrotaxane in the PU polymer. The systems are said to have processing and property advantages for specific elastomer applications, in this case printer rollers – if I understand the machine translation correctly.

Schematic presentation of a polyrotaxane

Schematic presentation of a polyrotaxane

SHSM Polyurethanes

Title: SHAPE-MEMORY-SELF-HEALING POLYMERS (SMSHPS)

 Number/Link: WO2015119688

Applicant/Assignee: University of Florida

Publication date: 13-08-2015

Gist”: Self-healing shape memory polyurethanes made by incorporation of DA adducts in-chain

Why it is interesting: According to this invention self-healing shape memory polyurethanes can be prepared by incorporating Diels-Alder (DA) adducts into the PU network such that the DA adducts do not contribute to the crosslinking.  In this manner the material can be heated above Tg without breaking crosslinks thereby inhibiting permanent distortion of the memorised shape. The Tg is also chosen such that it is lower than the temperature at which the retro-DA reaction readily occurs. The DA adducts can be introduced using a DA adduct-containing diol as for example the adduct of a furfuryl alcohol and N-(2-hydroxyethyl)maleimide.  The SHSM polyurethanes are said to be useful for coatings and moulded materials.

Diol containing a Diels-Alder adduct

Diol containing a Diels-Alder adduct

TPU for 3D Printing

Title: METHODS OF USING THERMOPLASTIC POLYURETHANES IN FUSED DEPOSITION MODELING AND SYSTEMS AND ARTICLES THEREOF .

 Number/Link: WO2015/109141

Applicant/Assignee: Lubrizol

Publication date: 23-07-2015

Gist”: TPU with specific crystallization temperature and modulus retention can be used for fused deposition modeling

Why it is interesting: Additive manufacturing in all its forms has been a steadily growing trend over the last few years.  Many different materials have been used in these processes, but the use of thermoplastic polyurethane has proven to be difficult because of its low crystallization rate, broad melting range and challenging melt-viscosity control.  According to this application TPU can be used for fused deposition modeling (“3D printing” by extruding molten thermoplastics) when it has a crystallization temperature of about 115°C and retains its shear modulus well with temperature.  Examples of such TPUs have a high harblock content (about 50%) and a molar ratio of chain extender to polyol of 2 to about 4,  and are prepared from 4,4′-MDI, butandiol and 2000 MW PTMEG polyether or butylene-adipate polyester diols.

Fused Deposition Modeling

Fused Deposition Modeling

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