All posts in category Flexible Foams

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

Polyurethane Foams with Reduced Acetaldehyde Emissions

Patent Title: POLYURETHANES WITH REDUCED ALDEHYDE EMISSION

Number/Link: WO2015/189095

Applicant/Assignee: BASF

Publication date: 17-12-2015

“Gist”: A polymer with pending -O-NH2 groups is used as additive

Why it is interesting: The reduction of VOC emissions, especially emissions of aldehydes from PU foams, remains an important topic of research. A number of solutions have been proposed, for example the use of polyamines as scavengers as discussed before. There still appears to be a need for improvement however, especially for the reduction of acetaldehyde emissions. According to this invention acetaldehyde emissions can be reduced by using a relatively high mole-weight polymer with pending aminooxy groups as an additive during foaming. In an example a copolymer of 4-aminooxymethylstyrene and methacrylic acid with a Mn of about 15,000 is used as an additive.

4-aminooxymethylstyrene

Innovation in Polyurethanes

All posts in category Flexible Foams

Flexible PU Foam with Very Low Resilience

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

Polyurethane Foams with Reduced Acetaldehyde Emissions

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