All posts tagged glass transition

In Situ Reticulated Viscoelastic Foams

Patent Title: VISCOELASTIC AND RETICULATED POLYURETHANE FOAM AND THE PREPARATION THEREOF

Number/Link: WO2016/198433

Applicant/Assignee: Covestro

Publication date: 15-dec-2016

“Gist”: Composition of 3 semi-miscible polyols and a surfactant

Why it is interesting: This case claims a polyol composition for the preparation of a viscoelastic, reticulated foam without the need for a separate reticulation step. The composition consists of (at least) three polyols and a surfactant: a low mole-weight all-PO ‘rigid’ triol, a conventional flexible polyol, a high- or all-EO polyol and some off-the-shelf silicone surfactant. The composition is foamed with water and polymeric MDI or a polymeric MDI/TDI mixture. This is a well-known composition and it is hard to see why this should result in a reticulated foam – unless maybe in some fine-tuned cases. Apart from the ball rebound being less than 15% the claims do not mention any parameters related to reticulated foam (such as airflow). It is doubtful (in my opinion) that this will get granted.

Cell structure of a reticulated foam

TPU/PU-Acrylate Semi-IPNs

Patent Title: THERMALLY STABLE MICROSTRUCTURED SEMI-IPN LAYER

Number/Link: WO2016/191118

Applicant/Assignee: 3M

Publication date: 1-dec-2016

“Gist”: TPU and PU-acrylate oligomers are blended and radiation-cured

Why it is interesting: According to this invention semi-interpenetrating polymer networks (IPNs) that are prepared from thermoplastic polyurethane (or urethane/urea) and acrylate-functional polyurethane oligomers are highly heat-stable and abrasion resistant and can be used for the production of microstructured surfaces. Microstructured (‘riblet’) surfaces with dimples or ridges of a few to a few hundred microns deep are used as drag reducing coatings on planes, ships and in aeronautics. In the examples 90% of a commercial TPU is blended and co-extruded with 10% of a commercial aliphatic urethane acrylate oligomer. The extruded film was then laminated on on a microreplicated liner, radiation cured and removed from the liner to produce the riblet surface.

Microstructured layer according to the invention

Soft Ionomeric TPU

Patent Title: SOFTENING THERMOPLASTIC POLYURETHANES USING IONOMER TECHNOLOGY

Number/Link: US20160347900

Applicant/Assignee: Univ. Akron; Covestro

Publication date: 1-Dec-2016

“Gist”: TPU is prepared with ionomeric groups having bulky counter-ions

Why it is interesting: According to this invention a novel type of plasticized thermoplastic polyurethane can be made by incorporating as chain extender a diol containing an ionic group with a bulky counter ion. It is said that the steric hindrance of the bulky counter ions creates additional free volume that softens the polymer and lowers the melt viscosity. In the examples N,N-bis(2-hydroxyethyl)-2-aminoethane sulfonic acid (BES) is used together with bulky alkylammonium cations. The softest TPU shown has a 37 Shore A hardness at 25% hardblock content and 7.6 mole% BES-tetrakis(decyl)ammonium. This accounts for a 35 point hardness decrease compared to an ionomer-free control sample.

N,N-bis(2-hydroxyethyl)-2-aminoethane sulfonic acid

Innovation in Polyurethanes

All posts tagged glass transition

In Situ Reticulated Viscoelastic Foams

TPU/PU-Acrylate Semi-IPNs

Soft Ionomeric TPU

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