Abstract: This invention relates to an improved process for producing a tanned heavy leather, sometimes called full thickness leather, suitable for use for shoe soles, belts and straps, bags and cases, and saddles, bridles, and harness, wherein, under carefully controlled pH conditions, leather stock is subjected to a multiple-stage tanning process involving a first treatment with an aqueous dispersion or solution of a synthetic polymeric composition made by polymerizing at least one member selected from the group consisting of acrylic acid and methacrylic acid and, optionally, one or more polymerizable compounds selected from the group of alkyl esters of acrylic acid, alkyl esters of methacrylic acid and sulfated unsaturated drying oils, followed by a second treatment with a zirconium tanning compound having a 0-45% basicity by the Schorlemmer scale.

Abstract: This invention relates to an improved process for producing a tanned heavy leather, sometimes called full thickness leather, suitable for use for shoe soles, belts and straps, bags and cases, and saddles, bridles, and harness, wherein, under carefully controlled pH conditions, leather stock is subjected to a multiple-stage tanning process involving a first treatment with an aqueous dispersion or solution of a synthetic polymeric composition made by polymerizing at least one member selected from the group consisting of acrylic acid and methacrylic acid and, optionally, one or more polymerizable compounds selected from the group of alkyl esters of acrylic acid, alkyl esters of methacrylic acid and sulfated unsaturated drying oils, followed by a second treatment with a zirconium tanning compound having a 0-45% basicity by the Schorlemmer scale.