Abstract: The invention relates to thermally expandable thermoplastic microspheres comprising a polymer shell made from ethylenically unsaturated monomers encapsulating a propellant, said ethylenically unsaturated monomers comprising from 20 to 80 wt % of acrylonitrile, from 20 to 80 wt % of monomers selected from the group consisting of esters of acrylic acid, from 0 to 10 wt % of methacrylonitrile, from 0 to 40 wt % of monomers selected from the group consisting of esters of methacrylic acid, the total amount of acrylonitrile and esters of acrylic acid constituting from 50 to 100 wt % of said ethylenically unsaturated monomers, and said propellant comprising at least one of methane, ethane, propane, isobutane, n-butane and isopentane. The invention further relates to the production and use of the microspheres.

Abstract: The invention relates to thermally expandable thermoplastic microspheres comprising a polymer shell made from ethylenically unsaturated monomers encapsulating a propellant, said ethylenically unsaturated monomers comprising from 20 to 80 wt % of acrylonitrile, from 20 to 80 wt % of monomers selected from the group consisting of esters of acrylic acid, from 0 to 10 wt % of methacrylonitrile, from 0 to 40 wt % of monomers selected from the group consisting of esters of methacrylic acid, the total amount of acrylonitrile and esters of acrylic acid constituting from 50 to 100 wt % of said ethylenically unsaturated monomers, and said propellant comprising at least one of methane, ethane, propane, isobutane, n-butane and isopentane. The invention further relates to the production and use of the microspheres.

Abstract: The invention relates to a process for the production of paper or nonwoven fibres comprising the steps of adding thermally expandable microspheres comprising a thermoplastic polymer shell and a propellant entrapped therein to a stock comprising fibres or to a web of fibres, forming paper or nonwoven from the stock or the web, and applying heat to raise the temperature of the microspheres sufficiently for them to expand and thereby increase the bulk of the paper or the nonwoven, wherein said expandable microspheres comprise from about 17 to about 40 wt % propellant and have a volume-average diameter from about 17 to about 35 µm. The invention also concerns certain expandable microspheres and use thereof.

Abstract: The invention relates to a process for the production of paper or nonwoven from fibres comprising the steps of adding thermally expandable microspheres comprising a thermoplastic polymer shell and a propellant entrapped therein to a stock comprising fibres or to a web of fibres, forming paper or nonwoven from the stock or the web, and applying heat to raise the temperature of the microspheres sufficiently for them to expand and thereby increase the bulk of the paper or the nonwoven, wherein said expandable microspheres comprise from about 17 to about 40 wt % propellant and have a volume-average diameter from about 17 to about 35 ?m. The invention also concerns certain expandable microspheres and use thereof.

Abstract: The invention relates to a process for the production of expandable thermoplastic microspheres comprising a step of contacting microspheres comprising a thermoplastic polymer shell encapsulating a propellant and further comprising residual monomers, with an agent reacting directly or indirectly with at least part of said residual monomers, wherein said agent is selected from the group consisting of oxo acids of sulfur, salts and derivatives thereof, comprising at least one sulfur atom having at least one free electron pair and binding three oxygen atoms. The invention further relates to novel expandable thermoplastic microspheres.

Abstract: The invention concerns a process for preparation of light weight objects comprising calendering, extrusion, blow or injection moulding a resin of polypropylene, polystyrene, HD polyethylene or copolymers thereof and, admixed therein, thermally expandable microspheres including a thermoplastic polymer shell encapsulating a propellant, at a temperature sufficient to result in expansion of the microspheres, wherein said polymer shell is made of a homo- or co-polymer from ethylenically unsaturated monomers comprising more than 80 wt % of nitrile containing monomers. The invention further concerns light weight objects obtainable by the process.

Abstract: The invention relates to thermally expandable microspheres comprising a thermoplastic polymer shell and a propellant entrapped therein, wherein said polymer shell is made of a homo- or co-polymer from ethylenically unsaturated monomers comprising more than 85 wt % of nitrile containing monomers and said propellant comprises at least 50 wt % of isooctane. The invention further relates to preparation and use of expandable microspheres, a composition comprising expandable microspheres and articles comprising foamed material containing expanded microspheres.

Abstract: The invention concerns a process for preparation of light weight objects comprising calendering, extrusion, blow or injection moulding a resin of polypropylene, polystyrene, HD polyethylene or copolymers thereof and, admixed therein, thermally expandable microspheres including a thermoplastic polymer shell encapsulating a propellant, at a temperature sufficient to result in expansion of the microspheres, wherein said polymer shell is made of a homo- or co-polymer from ethylenically unsaturated monomers comprising more than 80 wt % of nitrile containing monomers. The invention further concerns light weight objects obtainable by the process.

Abstract: The invention relates to thermally expandable microspheres comprising a thermoplastic polymer shell and a propellant entrapped therein, wherein said polymer shell is made of a homo- or co-polymer from ethylenically unsaturated monomers comprising more than 85 wt % of nitrile containing monomers and said propellant comprises at least 50 wt % of isooctane. The invention further relates to preparation and use of expandable microspheres, a composition comprising expandable microspheres and articles comprising foamed material containing expanded microspheres.