Polyrotaxanes in Flexible Foams

Patent Title: POLYOL COMPOSITION FOR PRODUCING FLEXIBLE POLYURETHANE FOAM..

 Number/Link: US20160304689

Applicant/Assignee: Toyo Tire & Rubber

Publication date: 20-10-2016

Gist”: Polyrotaxanes in PU foam reduces ‘wobble’ when used in car seats

Why it is interesting: The use of polyrotaxanes in polyurethanes is not new and has been discussed before in this blog.  According to the current invention polyrotaxanes with OH-functional rings can be incorporated in flexible foams, where they are said to reduce tensile stress while having little impact on compressive properties. When these foams are used in (e.g.) vehicle seats that are subject to low frequency sideways vibrations, they should reduce the sense of “wobble” of the occupants. The theory is that under tension the rings slide along the axis molecule equalizing stresses. In the examples polyrotaxanes with 11000 to 20000 molecular weight PEG axis molecules are used with cyclodextrin rings having an OHv of 43 to 85.

Polyrotaxane-crosllinked polyurethane under stress (schematic)

Polyrotaxane-crosslinked polyurethane under stress (schematic)

Self-Healing Polyurethane Coatings

Patent Title: Self-Repairing Polyurethane Networks

 Number/Link: US20160289495

Applicant/Assignee: Clemson University

Publication date: 6-10-2016

Gist”: Polyurethane networks with alkylated polysaccharide moiety show self-healing properties

Why it is interesting: Chitosan (pref.) is alkylated by reacting with dodecylaldehyde (in solvent) and reducing the resulting imine with sodium cyanoborohydride. The alkylated chitosan is then reacted with isocyanate and polyol.  When used as coating, the material is claimed to show self-healing properties when irradiated with UV light. Modifying the composition by incorporation of catechol, or by changing the saccharide allows for materials which ‘heal’ when exposed to ferric ions or carbon dioxide. No explanation for this behaviour is given and it is not immediately clear to me why this should work.

Self-healing network according to the invention. The isocyanate used was (E)-3,5-bis(6-isocyanatohexyl)- 6-( ( 6-isocyanatohexyl)imino )-1,3,5-oxadiazinane-2, 4-dione.

Self-healing network according to the invention. The isocyanate used was (E)-3,5-bis(6-isocyanatohexyl)-6-( ( 6-isocyanatohexyl)imino )-1,3,5-oxadiazinane-2,4-dione. ALK= alkyl, POL=polyol.

 

Polyurethane-Acrylate Plastisol

Patent Title: ACRYLIC-URETHANE IPN PLASTISOL

 Number/Link: US2016/0152857

Applicant/Assignee: Polyone

Publication date: 2-06-2016

Gist”: Plastisols from blocked-iso grafted acrylate in plasticizer

Why it is interesting:
Conventional plastisols are suspensions of PVC particles in a (usuallly phthalate-) plasticizer. The suspension can be cured by heating, which results in a plasticized elastomer.  Plastisols are used for coatings of e.g. car underbodies and for ‘screen printing’ of textiles. According to this invention a non-PVC plastisol can be produced by dispersing core-shell acrylate polymer particles (Mn between 300,000 and 1,000,000) with blocked isocyanate groups grafted to the backbone into a plasticizer, preferably into dioctylphthalate, together with a latent amine crosslinker like adipic dihydrazide. No information is given about the blocking agent but the plastisol is said to cure at 130-170°C and be especially suited for textile printing.

Adipic dihydrazide

Adipic dihydrazide

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