All posts tagged memory foam

Viscoelastic TDI “Hot Cure” Foams

Title: POLYURETHANE FOAM

 Number/Link: WO2013/108582 (Japanese)

Applicant/Assignee: SMP TECHNOLOGIES

Publication date: 25-07-2013

“Gist”: A (semi-) flexible foam with a Tg of around body temperature is prepared from a mixture of PO polyols and TDI.

Why it is interesting: a The viscoelastic foams of this invention are prepared from a mixture of popyoxypropylene diols and triols with molecular weights varying between 200 and 3000 (up to 5 different polyols in the examples) together with TDI 80:20, water and conventional additives. Because of the all-PO polyols the foams have to be post-cured at high temperature (‘hot cure’).  The foams have a damping (tan δ) of over 0.4 between 0 and 40°C (measured at 1Hz in the examples) and between 0.1 and 100Hz (measured at 25ºC) as shown in the graphs below. (Note that because of the time-temperature superposition principle the second graph is actually redundant.) The foams are supposedly useful ‘to be worn on the body’ – I suppose they mean liners for helmets, shoes, pads, sports gear and the like.

Storage- and Loss modulus and damping vs temperature at 1Hz

Storage- and Loss modulus and damping vs temperature at 1Hz

loss tangent freq

Storage- and loss modulus and damping vs frequency at 25°C

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by Gerhard Bleys on July 30, 2013  •  Permalink
Posted in Flexible Foams
Tagged , , , ,

Posted by Gerhard Bleys on July 30, 2013

https://purpatents.com/2013/07/30/viscoelastic-tdi-hot-cure-foams/

Improved Viscoelastic Flexible Foams (“Memory Foams”)

Title: USE OF POLY(BUTYLENE OXIDE) POLYOL TO IMPROVE DURABILITY OF MDI-POLYURETHANE FOAMS

Patent Number & Link:  US2013178548    (related case US2013178550 )   

Applicant/Assignee: Dow

Publication date: 11-07-2013 (priority PCT/US)

“Gist”: Use of a high molecular weight butyleneoxide monol to improve the compression set of viscoelastic foams.

Why it is interesting: Viscoelastic or “memory” flexible foams are currently popular for use in matresses and pillows. Much research and development has been done on these materials and the patent situation is a true minefield. Usually a mixture of EO-rich and PO-rich polyols of different molecular weights is used to control the glass transition temperature (Tg) of the softblock, wich in turn controls the energy absorption (and thus the resilience) of the foam. In this invention a butyleneoxide monol of high MW is used in addition to a mixture of EO-rich and PO-rich polyols. The BO-monol is used in an amount of 2-10% on the polyol  and supposedly improves compression set while retaining the open cell character (air flow) of the foam.
The related case (US2013/178550) is similar but uses a high MW PO polyol with a functionality between 1 and 4 instead of the BO monol.  It is not immediately clear to me whether this latter case is a real invention or is just plugging a hole in the minefield..

A viscoelastic flexible foam

A viscoelastic flexible foam

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by Gerhard Bleys on July 25, 2013  •  Permalink
Posted in Flexible Foams, Polyols
Tagged , , , , ,

Posted by Gerhard Bleys on July 25, 2013

https://purpatents.com/2013/07/25/improved-viscoelastic-flexible-foams-memory-foams/

Viscoelastic Polyurethane Foam with Porous Struts

Title: CELLULAR STRUCTURES AND VISCOELASTIC POLYURETHANE FOAMS

 Number/Link: US2013035413

Applicant/Assignee: DOW GLOBAL TECHNOLOGIES

Publication date: 7-02-2013

“Gist”: The use of high equivalent weight polybutylenoxide monol together with a polyol mixture and TDI to produce a viscoelastic  foam with greatly improved airflow.

Why it is interesting: Most viscoelastic (or “memory”) foams are used in bedding and often have the disadvantage of building up heat and moisture during use, resulting in the loss of viscoelastic properties and deterioration in comfort. Improving the airflow through the foam should reduce this effect. Dow now appears to have cracked the airflow problem by using  a polybutylene oxide monol (preferred) with and eq.wt. of about 4000, together with a conventional blend of high EO and high PO polyols and TDI80 (in the examples).  Air flow indeed seems to be greatly improved and even the cell struts appear to be perforated!  Great stuff.

Foams cells showing porous struts

Foams cells showing porous struts

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by Gerhard Bleys on February 12, 2013  •  Permalink
Posted in Flexible Foams
Tagged , ,

Posted by Gerhard Bleys on February 12, 2013

https://purpatents.com/2013/02/12/viscoelastic-polyurethane-foam-with-porous-struts/

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