All posts tagged smart materials

Matte, Self-Healing Polyurethane Powder Coatings

Title: POLYURETHANE COATING COMPOSITION

Number/Link: WO2017/074835

Applicant/Assignee: Valspar

Publication Date: 4 May 2017

“Gist”: Coating composition comprising isocyanate and two polyester polyols having a similar Tg but a widely different equivalent weight.

Why it is interesting: Conventionally low gloss or “matte” coatings are the result of a microtextured surface achieved by certain fillers or by incompatible polymers and the like. According to this invention “ultra matte” finishes can also -surprisingly- be achieved from a (powder) coating composition comprising a (blocked) isocyanate and a mixture of two polyester polyols. Both polyols have a Tg between 40 and 60ºC prefereably differing not more than 5 to 8ºC, while the OHv of the first polyol is between 150 and 325 and that of the second between 15 and 35. The ratio between first and second polyol is from about 1:1 to 1:3 w/w. Also surprisingly, the resulting coatings are said to show self-healing properties. An interesting composition but no examples of the polyesters or isocyanates used are given.

Car with matte finish

TPU with Anti-Biofouling Surface

Patent Title: ANTIFOULING COMPOSITION

Number/Link: WO2017/007899

Applicant/Assignee: BASF

Publication date: 12-jan-2017

“Gist”: TPU containing silicone diol and having microstructured surface

Why it is interesting: Biofouling of surfaces e.g. in the marine environment or of medical implants is a problem. For example the growth of barnacles on the hulls of vessels, subsea cables, pipes and energy generating structures has a significant economic impact. According to this invention, thermoplastic polyurethane articles with a surface energy of about 20 mN/m and a microstructered surface topography show an improved resistance to biofouling. The TPU is produced by incorporating 5-15% on the total composition of a PDMS diol with a OH value of 15 to 150, and by pressing onto the surface a 3D topology with ‘peaks’ and ‘valleys’ of an order of magnitude of 10μm.

Microstructured surface according to the invention

Liquid Crystalline Polyurethane Elastomers

Patent Title: LIQUID CRYSTALLINE POLYURETHANE ELASTOMER AND METHOD FOR PRODUCING SAME

Number/Link: US 2016/0376396

Applicant/Assignee: Toyo Tire & Rubber

Publication date: 29-dec-2016

“Gist”: Specific mesogenic diols are used together with high MW polyols and high functionality isocyanate

Why it is interesting: The invention is about thermotropic liquid crystalline PU elastomers, where the liquid crystalline (LC) phase is formed at relatively low temperatures (e.g. near room temperature). This is accomplished by preventing the mesogen to crystallize, such that it shows no melting point between its Tg and Ti (LC phase -to- isotropic phase transition temperature). This, in turn, is accomplished by using a high molecular weight polyol together with a high functionality isocyanate and a mesogenic diol of the structure shown below where Y represents -N=N-, -CO-, -CO-O- or -CH=N- and X represents a C3 to C20 alkylene. Under stress the elastomer extends in the orientation direction by increasing the LC content and shrinks by reducing LC content. It can therefore be used as a temperature-controlled actuator.

General structure of the mesogenic diol of the invention

Innovation in Polyurethanes

All posts tagged smart materials

Matte, Self-Healing Polyurethane Powder Coatings

TPU with Anti-Biofouling Surface

Liquid Crystalline Polyurethane Elastomers

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