| 摘要 |
Self-sealing compositions are prepared by mixing with vigorous agitation a solid, water-insoluble resin or resin mixture having a softening point of 95 DEG C. or less heated to above the softening point, with an aqueous dispersion of a non-toxic and chemically neutral vinyl ether polymer or copolymer, mixing the mixture obtained with an aqueous dispersion of a polymer or copolymer of an acrylic acid derivative selected from polyacrylic acid esters, polymethacrylic acid esters, and copolymers of acrylic acid esters or methacrylic acid esters with other monomers copolymerizable therewith. The resin may be natural or synthetic, e.g. polyterpenes, ester resins, colophony or hydrogenated or polymerized colophony. Fillers, thickening agents, medicaments, anti-ageing agents and/or stabilizers can be added. The composition comprises in Examples (1) 4 parts phthalic acid ester resin mixed with 4 parts abietyl alcohol, 39 parts of an aqueous polyvinyl isobutyl ether dispersion, 53 parts of an aqueous dispersion of a polyacrylic acid ester and has a sol viscosity of 2300 cp. at 20 DEG C.; (2) 35 parts of the aqueous polyvinyl isobutyl ether dispersion of (1), 17 parts phthalic acid ester resin, 48 parts aqueous dispersion of acrylic acid ester copolymer and has a sol viscosity >105 cp. at 20 DEG C.; (3) 6 parts polyterpene resin, 39.5 parts of the aqueous polyvinyl ether dispersion, 54.5 parts of the aqueous polyacrylate dispersion of (1) and has a sol viscosity 1380 cp./20 DEG C.; (4) 6 parts of a polyterpene resin mixture, 40 parts of an aqueous polyvinyl isobutyl ether dispersion, 54 parts of an aqueous dispersion of a polyacrylic acid ester; (5) 17 parts of a polyterpene resin mixture, 35 parts of the aqueous polyvinyl ether dispersion, 48 parts of an aqueous dispersion of an acrylic acid ester copolymer and has a sol viscosity of 1160 cp./20 DEG C.; (6) 17 parts phthalic acid ester resin, mixed with 17 parts of an abietyl alcohol, 28 parts of an aqueous polyvinyl isobutyl ether dispersion, 38 parts of an aqueous dispersion of a polyacrylic acid ester and has a sol viscosity >105 cp./20 DEG C.ALSO:Pressure sensitive adhesive strips, foils, such as medical plasters, are produced by mixing with vigorous agitation a solid, water insoluble resin, or mixture of such resins, having a softening point of 95 DEG C or less heated to a temperature above the softening point, with an aqueous dispersion of a non toxic, chemically neutral vinyl ether polymer or copolymer, such as polyvinyl isobutyl ether, mixing the mixture obtained with an aqueous dispersion of a polymer or copolymer of an acrylic acid derivative selected from polyacrylic, polymethacrylic acid esters and copolymers of acrylic, methacrylic acid esters with other monomers copolymerisable therewith, applying the mixture thus obtained as a layer on a flexible carrier material and drying the layer. Natural or synthetic resins may be used, e.g. polyterpene resins, esters, colophony or hydrogenated or polymerised colophony or hydrocarbon resins. In Examples (1) a mixture of phthalic acid ester and abietyl alcohol (2) phthalic acid ester resin is used. Resins having a softening point above 100 DEG C may be used if other water-insoluble, low melting resins are added such that the softening point of the mixture is reduced at least to 95 DEG C. Fillers, thickening agents, medicaments, anti-ageing agents and/or stabilisers can be added. Carriers mentioned are paper, fabric, fleeces, foils of plastics or modified natural substances, such as regenerated cellulose or cellulose derivatives, metal foils, fabrics of asbestos and glass fibre. In the Examples (2) a polyvinyl chloride foil (3) a fibre fleece made of staple fibres obtained from viscose and impregnated with acrylic acid esters copolymer (4) a fabric made from cotton or rayon staple fibre (5) fabric of nylon staple fibres form the carrier material. A printing coating or intermediate coating can be used to anchor the adhesive composition more firmly on the carrier, e.g. a coating of a copolymer of butadiene and acrylonitrile and a copolymer of butadiene and styrene. The polyvinyl ether dispersion may be preheated to 40 to 70 DEG C. The coating may be dried in a drying tunnel or reel drying may be used. |
