Dye removal from denim scrap with a forced circulation kier
First Claim
1. A process for liquid treatment of denim scrap comprising the steps of:
- a) placing sufficient denim scrap pieces on a support surface to form a thickness of flat, layered denim scrap comprising individual denim pieces with opposed surfaces having approximately parallel orientations, the thickness having a top surface;
b) applying a compression plate to said top surface to form the thickness of denim scrap into a compact cake; and
c) passing liquid through the interior of the compact cake in a direction parallel to the surfaces of the scrap, the liquid passing between opposed surfaces of the denim pieces.
10 Assignments
0 Petitions
Accused Products
Abstract
A recycling process for liquid treatment of denim scrap comprising placing denim scrap on a support surface to form a thickness of flat, layered denim scrap. To the top surface is applied a compression plate to form the thickness of denim scrap into a compact cake. Then treatment liquid is passed through the interior of the compact cake in a direction parallel to the surfaces of the scrap, the liquid passing between opposed surfaces of the denim pieces. The denim scrap is preferably cut into relatively uniform sizes having their largest dimension less than about 4 inches. The treatment liquid can be a solvent for oxidized indigo dye, whereby indigo dye is removed from the denim scrap by said liquid; an aqueous solution containing a desizing agent, whereby size is removed from the denim scrap pieces; an aqueous solution containing a reducing agent for indigo dye, whereby dye in the denim pieces is reduced to a soluble, leuco form, dissolves in the solution, and both size and dye are removed from the denim scrap pieces; a solution containing desizing and reducing agent, whereby size and dye is removed from the denim scrap pieces; or an aqueous solution containing a reducing agent for indigo dye, whereby dye in the denim pieces is reduced to a soluble, reduced form, dissolves in the solution, and is removed from the denim scrap pieces; or a sequences of these liquids.
4 Citations
16 Claims
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1. A process for liquid treatment of denim scrap comprising the steps of:
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a) placing sufficient denim scrap pieces on a support surface to form a thickness of flat, layered denim scrap comprising individual denim pieces with opposed surfaces having approximately parallel orientations, the thickness having a top surface;
b) applying a compression plate to said top surface to form the thickness of denim scrap into a compact cake; and
c) passing liquid through the interior of the compact cake in a direction parallel to the surfaces of the scrap, the liquid passing between opposed surfaces of the denim pieces. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A process for liquid treatment of denim scrap to remove dye from the scrap and decolorize the scrap comprising the steps of:
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a) placing sufficient denim scrap pieces on a support surface to form a thickness of flat, layered denim scrap comprising individual denim pieces with opposed surfaces, the thickness having a top surface;
b) applying a compression plate to said top surface to form the thickness of denim scrap into a compact cake;
c) passing a first aqueous solution through the interior of the compact cake in a direction parallel to the surfaces of the scrap, the first aqueous solution passing between opposed surfaces of the denim pieces, the first aqueous solution containing reducing agent for indigo dye, whereby dye in the denim pieces is reduced to a soluble, reduced form, dissolves in the solution, and is removed from the denim scrap pieces; and
d) passing a second aqueous solution through the interior of the compact cake in a direction parallel to the surfaces of the scrap, the second aqueous solution passing between opposed surfaces of the denim pieces, the second aqueous solution containing catalyzed hydrogen peroxide solution, the catalyst being an catalyzing amount of a transition metal cation or quaternaryalkylamine salt which catalyzes oxidation reactions of hydrogen peroxide, whereby indigo dye, other vat dyes, and sulfur dyes in the denim scrap pieces are bleached or destroyed to remove color therefrom. - View Dependent Claims (11, 12, 13, 14, 15)
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16. A process for liquid treatment of denim scrap to remove dye from the scrap and decolorize the scrap comprising the steps of:
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a) placing sufficient denim scrap pieces on a support surface to form a thickness of flat, layered denim scrap comprising individual denim pieces with opposed surfaces, the thickness having a top surface;
b) applying a compression plate to said top surface to form the thickness of denim scrap into a compact cake;
c) passing a first aqueous solution through the interior of the compact cake in a direction parallel to the surfaces of the scrap, the first aqueous solution passing between opposed surfaces of the denim pieces, the first aqueous solution containing reducing agent for indigo dye, whereby dye in the denim pieces is reduced to a soluble, reduced form, dissolves in the solution, and is removed from the denim scrap pieces; and
d) passing a second aqueous solution through the interior of the compact cake in a direction parallel to the surfaces of the scrap, the second aqueous solution passing between opposed surfaces of the denim pieces, the second aqueous solution containing an alkali metal hypochlorite whereby the indigo vat dye, other vat dyes, or sulfur dyes are bleached or destroyed.
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Specification