Dart Industries Inc.

Plastic Specialties and Technologies, Inc.

Moenes L Elias

Silvester P Valayil

Walter L Burger

Philip D Readio

Millard F Good

Narendra K Shah

Improved metal dissolution rates are obtained when using a solution containing sulfuric acid, hydrogen peroxide and a catalytic amount of tungsten.

Dissolution of metals utilizing tungsten

Improved metal dissolution rates are obtained when using a solution containing sulfuric acid, hydrogen peroxide and combinations of catalytic amounts of tungsten and of certain diols.

Dissolution of metals utilizing tungsten-diol combinations

Improved metal dissolution rates are obtained when using a solution containing sulfuric acid, hydrogen peroxide and certain primary diols.

Dissolution of metals

A composition for stripping solder and tin from a copper substrate having an extended life is provided by the inclusion of a polyacrylamide in a peroxide-fluoride based stripping composition. The presence of the polyacrylamide minimizes the adverse effect of the stripping composition on the copper substrate of the material undergoing treatment.

Metal stripping composition and method

Improved metal dissolution rates are obtained when using a solution containing sulfuric acid, hydrogen peroxide and a catalytic amount of a heterocyclic nitrogen compound containing at least one free mercapto group substitution.

Dissolution of metals utilizing an aqueous H.sub.2 SO.sub.Y --H.sub.2

Improved metal dissolution rates are obtained when using a solution containing sulfuric acid, hydrogen peroxide and a catalytic amount of a thioamide having the general formula ##STR1## wherein R is an aryl or a heterocyclic group.

Dissolution of metals utilizing an aqueous H.sub.2 O.sub.2 -H.sub.2

Improved metal dissolution rates are obtained when using a solution containing sulfuric acid, hydrogen peroxide and a catalytic amount of 3-sulfopropyldithiocarbamate sodium salt having the general formula ##STR1## wherein R can be a C.sub.1 -C.sub.4 alkyl group, phenyl, a C.sub.7 -C.sub.10 alkaryl group or a C.sub.7 -C.sub.10 aralkyl group.

Dissolution of metals utilizing an aqueous H.sub.2 SO.sub.4 -H.sub.2

Improved metal dissolution rates are obtained when using a solution containing sulfuric acid, hydrogen peroxide and a catalytic amount of a polysulfide compound having the general formula ##STR1## wherein R is a hydroxyl group, a carboxyl group, a sulfonic acid group or a sulfonic acid salt group, each X independently from each other can be hydrogen, hydroxyl or C.sub.1 -C.sub.4 alkyl, each Y independently from each other can be hydrogen, hydroxyl or C.sub.1 -C.sub.4 alkyl, m is an integer from 1 to 18, and n is an integer from 2 to 5.

Improved metal dissolution rates are obtained when using a solution containing sulfuric acid, hydrogen peroxide and an effective amount of a mono- or dihydroxy-substituted cycloparaffin.

Dissolution of metals utilizing a H.sub.2 O.sub.2 -H.sub.2 SO.sub.4

Improved metal dissolution rates are obtained when using a solution containing sulfuric acid, hydrogen peroxide and a catalytic amount of a thiosulfate of sodium or potassium.

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Canfield, OH, United States of America

Moenes L Elias