Reticulated Foam-Fiber Composites

Title: A RETICULATED OPEN-CELL FOAM MODIFIED BY FIBERS EXTENDING ACROSS AND BETWEEN THE CELLS OF SAID FOAM AND PREPARATION METHODS THEREOF

 Number/Link: WO2013010245

Applicant/Assignee: EPIC VENTURES INC

Publication date: 24-01-2013

Gist”: Reticulated polyurethane foams containing fibers extending across and between cells. The foams can then be impregnated with metals (Nickel) and the polymer pyrolized resulting in porous metal structures useful in batteries.

Why it is interesting:  Reticulated foams (i.e. foams consisting only of a ‘strut skeleton’ and having no cell membranes) are well known, but the application is not clear about which process is to be used in this case, neither does it provide an example of a formulation. Chopped metal, glass or carbon  fibers are added to the foam-forming composition supposedly ‘resulting’ in a reticulated foam/fibre composite.  The fibers extend over about 5 cell diameters (e.g. 1-1.5 mm ) and are used in 10-30% v/v. Foams like this could be interesting for filtration, heat exchange and especially sound absorption -with  the fibers adding extra “tortuosity”. The patent is mainly concerned with the subsequent production of metal foams for use in batteries e.g.

Reticulated Foams with Fibers

Reticulated Foam with Fibers

Polyurethane Integral Skin Foam with Improved Acoustic Properties

Title:  INCREASING THE SOUND ABSORPTION IN FOAM INSULATING MATERIALS

 Number/Link: WO2013/007243  (German)

Applicant/Assignee: OTTO BOCK SCHAUMSYSTEME GMBH

Publication date: 17-01-2013

Gist”: Use of  expandable graphite to improve sound absorption and sound insulation properties of  integral skin foams.

Why it is interesting: Expandable graphite is well known as an intumescent flame retardant in coatings and in e.g. low-density (semi-) rigid PU foams, including acoustic foams. This case claims the use of 5-40% (w/w on polyol) of non pre-expanded expandable graphite in a (preferably) 200-300 kg/m3 integral skin foam, resulting in improved sound absorption coefficients and sound insulation (transmission loss?).  It is contemplated that it is the layered structure of the graphite that absorbs the acoustic energy…

 

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