All posts tagged comfort

Flexible PU Foam with Very Low Resilience

Patent Title: LOW-RESILIENCE POLYURETHANE FOAM AND PRODUCTION METHOD THEREOF

Number/Link: US2016/0024268

Applicant/Assignee: Mitsui

Publication date: 28-01-2016

“Gist”: Use of trans-BIC in viscoelastic flex foam

Why it is interesting: According to this invention low resilience flexible foams can be produced by reacting a mixture of two (optionally three) polyether polyols, water, a crosslinker and a catalyst with 1,4-bis(isocyanatomethyl)cyclohexane (BIC) where the BIC consists of (pref) 90% or more of the trans isomer. Higher trans-isomer is said to result in higher airflow and a finer cellstructure. In the examples a high MW all-PO triol and a low MW EO/PO triol with 18% EO tip is used, together with BIC at an NCO index of 70%. The resulting foams have a high airflow and a (very) low resilience at densities between 50 and 70 kg/m³. While trans-BIC is clearly an interesting aliphatic di-iso, it is not widely available.

trans-1,4-bis(isocyanatomethyl)cyclohexane

Classic PU Patent of the Month: ICI on “High EO – Pure MDI” Flexible Foams (1991)

Patent Title: Polyurethane Foams

Number/Link: EP0547765

Applicant/Assignee: ICI

Publication date: 23-06-1993

“Gist”: Flexible foams can be based on 4,4’MDI if the polyol contains 50 to 85% EO

Why it is interesting: The first flexible PU foams were all based on toluene diisocyanate and so-called “conventional polyols” (i.e. almost all-propylene oxide polyols). Attempts to replace TDI by the only other commercially viable diisocyanate (4,4′ MDI) failed because of premature phase separation of the highly symmetrical polyurea ‘hard block’, resulting in unstable foaming. The problem was eventually solved by using prepolymers and polymeric MDI, as mentioned before. More than 10 years later it was shown that it is possible to make flexible foams with 4,4′-MDI if the polyol is polar enough to prevent early phase separation. This was established by using polyols with high ethylene oxide content. The resulting foams have superior comfort and durability properties compared to both TDI and MDI flexible foams.

4,4′-MDI

Classic PU patent of the Month: PORON ® Foams (1979)

Title: Polyurethane foam product and process of manufacture thereof from thermosetting frothed mixture

Number/Link: US4216177

Applicant/Assignee: Rogers

Publication date: 5-08-1980

“Gist”: Frothed flexible foam

Why it is interesting: PORON is a popular brand of microcellular elastomeric/flexible polyurethane foams produced by Rogers Corporation. The original process, as documented in this patent, is quite simple: a flexible foam formulation (in the examples) based on TDI, caprolacton diol, polymer polyol, some chain extender, amine catalyst and surfactant is frothed instead of blown with water or a physical blowing agent. The reacting froth is poured on release paper and heated to cure. Release paper can also be applied on top resulting in an integral skin on both sides of the layer. Frothing instead of blowing results in an improved compression set, different hardness-density relationship and a better control over cell structure. A unique material.

PORON foams

Innovation in Polyurethanes

All posts tagged comfort

Flexible PU Foam with Very Low Resilience

Classic PU Patent of the Month: ICI on “High EO – Pure MDI” Flexible Foams (1991)

Classic PU patent of the Month: PORON ® Foams (1979)

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