GB1088468A - Low density aerosol filter - Google Patents

Abstract

A material used to filter smoke in a pipe, cigarette or cigar is made by adding at least one elastomeric, hydrophobic latex to a slurry comprising fibrilated cellulosic fibres, adding a surfactant and foaming the slurry, coagulating the latex, shaping and drying the resulting cellular fibrous structure in its expanded condition. The coagulation of the latex may be achieved by the action of a resin, added to the slurry before or with the latex or premixed with the latex, or two incompatible latexes (poly-vinyl chloride and poly-acrylonitrile) may coagulate each other, or an inorganic salt or the foaming agent may effect coagulation. Examples of resin-latex-surfactant combinations are melamine-formaldehyde resin, styrene-butadiene latex, sodium dodecyl benzene sulphate surfactant, urea-formaldehyde resin, styrene-butadiene latex, dodecyl dimethyl amine oxide surfacant; melamine-formaldehyde resin, poly acrylonitrile latex, sodium dodecyl benzene sulphonate surfactant. In general, the slurry has a 1.5% consistency and 0.2%-2% of resin and 1-20% of latex (based on the weight of fibres) are added, followed by 0.01%-0.2% (based on the slurry) of surfactant, and the slurry is beaten to expand it to 1.5-3 times its initial volume. The stiff foam may then be extruded to "filter tip" size and then dried, or cast and drained on a screen to give a low density product (0.06 lbs/sq. foot, 1.0 lbs/cu. foot), which is subsequently cut into strips and compressed to form "filter tips". The "filter tips" have a density of 7.0 lbs/cu. foot. The cellulosic fibres may be cotton linter, sulphite and sulphate wood, rayon staple, polystyrene grafted cellulose or cellulose acetate fibres and are fibrilated by mechancial treatment of the slurry. The slurry may also include glass, absestos, polyolefin, polyamide and polyester fibres and activated carbon.ALSO:A material used to filter smoke in a pipe, cigarette or cigar is made by adding at least one elastomeric, hydrophobic latex to a slurry comprising fibrilated cellulosic fibres, adding a surfactant and foaming the slurry, coagulating the latex, shaping and drying the resulting cellular fibrous structure in its expanded condition. The coagulation of the latex may be achieved by the action of a resin, added to the slurry before or with the latex or premixed with the latex, or two incompatible latexes (poly-vinyl chloride and poly-acrylonitrile) may coagulate each other, or an inorganic salt or the foaming agent may effect coagulation. Examples of resin-latex-surfactant combinations are melamine-formaldehyde resin, styrene-butadiene latex, sodium dodecyl benzene sulphate surfactant, urea-formaldehyde resin, styrene-butadiene latex, dodecyl dimethyl amine oxide surfactant; melamine-formaldehyde resin, poly acrylonitrile latex, sodium dodecyl benzene sulphonate surfactant. In general, the slurry has a 1.5% consistency and 0.2%-2% of resin and 1-20% of latex (based on the weight of fibres) are added, followed by 0.01%-0.2% (based on slurry) of surfactant, and the slurry is beaten to expand it to 1.5-3 times its initial volume. The stiff foam may then be extruded to "filter tip" size and then dried, or cast and drained on a screen to give a low density product (0.06 lbs./sq. foot, 1.0 lbs./cu. foot), which is subsequently cut into strips and compressed to form "filter tips". The "filter tips" have a density of 7.0 lb./ cu. foot. The cellulosic fibres may be cotton linter, sulphite and sulphate wood, rayon staple, polystyrene grafted cellulose or cellulose acetate fibres and are fabrilated by mechanical treatment of the slurry. The slurry may also include glass, asbestos, polyolefin, polyamide and polyester fibres and activated carbon.ALSO:A material used to filter smoke in a pipe, cigarette or cigar is made by adding at least one elastomeric, hydrophobic latex to a slurry comprising fibrilated cellulosic fibres, adding a surfactant and foaming the slurry, coagulating the latex, shaping and drying the resulting cellular fibrous structure in its expanded condition. The coagulation of the latex may be achieved by the action of a resin, added to the slurry before or with the latex or premixed with the latex, or two incompatible latexes (poly-vinyl chloride and poly-acrylonitrile) may coagulate each other, or an inorganic salt or the foaming agent may effect coagulation. Examples of resin-latex-surfactant combinations are melamine-formaldehyde resin, styrene-butadiene latex, sodium dodecyl benzene sulphate surfactant, urea-formaldehyde resin, styrene-butadiene latex, dodecyl dimethyl amine oxide surfactant; melamine-formaldehyde resin, poly-acrylonitrile latex, sodium dodecyl benzene sulphonate surfactant. In general, the slurry has a 1.5% consistency and 0.2% -2% of resin and 1-20% of latex (based on the weight of fibres) are added, followed by 0.01% - 0.2% (based on slurry) of surfactant, and the slurry is beaten to expand it to 1.5-3 times its initial volume. The stiff foam may then be extruded to "filter tip" size and then dried, or cast and drained on a screen to give a low density product (0.06 lbs./sq. foot, 1.0 lbs./cu. foot), which is subsequently cut into strips and compressed to form "filter tips". The "filter tips" have a density of 7.0 lb./ cu. foot. The cellulosic fibres may be cotton linter, sulphite and sulphate wood, rayon staple, polystyrene grafted cellulose or cellulose acetate fibres and are fibrilated by mechanical treatment of the slurry. The slurry may also include glass, asbestos, polyolefin, polyamide and polyester fibres and activated carbon.