Claims
- 1. A cyclic method for the machine washing of soiled solid materials with a washing solution prepared from hard water in a washing area, which comprises in sequence:
- (a) forming a charge of an aqueous washing solution having a dissolved content between 0.05 gm/liter and 2 gm/liter of a water-soluble calcium-binding sequestrant, and customary surface-active compounds selected from the group consisting of an anionic detergent and a nonionic detergent,
- (b) filtering said washing solution through a filter bed separate and spaced from the washing area to form a filtrate, said filter bed having a previously incorporated content of a water-insoluble cation-exchange polymer in particulate state having a swelled average particle diameter in excess of 20.mu. and having a calcium binding power of at least 2 mVal/gm, said polymer being a copolymer or graft polymer derived from olefinically-unsaturated carboxylic acids, said water-insoluble cation-exchange polymer being separated from said washing solution by said filter bed, the amount of the water-insoluble cation-exchange polymer being so selected that the residual hardness of the filtrate is less than 20 mg CaO/liter;
- (c) washing said soiled material with said filtrate as washing medium;
- (d) continuously pumping at least part of said washing medium through said particulate cation-exchange polymer on said filter bed and recycling the filtrate having less than 20 mg CaO/l to said washing area, at such a rate that said washing medium passes a total of at least five times through said particulate cation-exchange polymer during said washing step; and
- (e) continuing said recycling until said soiled solid material is substantially cleaned.
- 2. A process according to claim 1 wherein said water-soluble calcium-binding sequestrant is selected from the group consisting of the pyrophosphates, tripolyphosphates, polyphosphates and metaphosphates; polycarboxylic acids; hydroxycarboxylic acids; aminocarboxylic acids; carboxyalkyl ethers; polyanionic polymeric acids; polyphosphonic acids, and mixtures thereof.
- 3. A process according to claim 1 wherein the amount of said sequestrant is 0.1 to 1 gram per liter of said solution.
- 4. A process according to claim 1 wherein said water-insoluble cation exchange polymer is a copolymer of a molar excess of acrylic acid and hexamethylene-bisacrylamide.
- 5. A process according to claim 1 wherein said water-insoluble cation exchange polymer has a calcium binding capacity in excess of 8 mVal/gm.
- 6. A process according to claim 1 wherein the solid materials washed are textile garments.
- 7. A process according to claim 1 wherein the washing solution contains less than 0.6 gram per liter of combined phosphorus.
- 8. A process according to claim 1 wherein the washing solution contains substantially no combined phosphorus.
- 9. A process according to claim 1 wherein said washing solution is cycled from 10 to 50 times through said particulate cation-exchange polymer.
- 10. A method according to claim 1 wherein the temperature of the washing solution is between about 30.degree. C. and 100.degree. C.
Priority Claims (1)
Number |
Date |
Country |
Kind |
10204/74 |
Dec 1974 |
ATX |
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Parent Case Info
This is a continuation of Ser. No. 639,465, filed Dec. 10, 1975, and now abandoned.
US Referenced Citations (6)
Foreign Referenced Citations (3)
Number |
Date |
Country |
2307923 |
Oct 1973 |
DEX |
2216467 |
Apr 1974 |
DEX |
2411466 |
Oct 1974 |
DEX |
Continuations (1)
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Number |
Date |
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Parent |
639465 |
Dec 1975 |
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