Method of laundering industrial garments
Metallic based oily soils can be removed from garments by subjecting the garments to a pre-wash in an aqueous solution of a hydroxy diphosphonic acid such as HEDP under acidic conditions. Pre-washing the garments in the aqueous solution of HEDP at about 100 to 212 degrees Fahrenheit for about 15 minutes effectively removes the greasy soils, allowing them to be further laundered with an alkaline detergent composition.
1. A method of laundering garments having metallic-based oily soil including a hydrocarbon portion and at least one of metal particles and metal oxide particles comprising prewashing said garments in an aqueous solution of 1-hydroxy ethylidene-1, 1-diphosphonic acid at about 100° F. to about 212° F. at a pH of 3-5 for a time effective to cause removal of metallic based oily soils and subsequently washing said garments in an alkaline detergent solution; and
wherein said aqueous solution of 1-hydroxy ethylidene-1, 1-diphosphonic acid does not include any of alkaline components, detergent builders, anionic surfactant, cationic surfactants or bleach in amounts sufficient to effect said garments during laundering.
2. The method claimed in claim 1 wherein said effective time is from about 5 to about 30 minutes.
3. The method claimed in claim 1 wherein said effective temperature is about 150° F.
4. The method claimed in claim 1 wherein said aqueous solution includes from about 1.75 to about 20 ounces of 1-hydroxy ethylidene-1, 1-diphosphonic acid per 100 lbs of fabric.
5. The method claimed in claim 1 wherein said aqueous solution includes a nonionic surfactant in an amount effective to lower the surface tension between the fabric/soil-water interface and help disperse soils dislodged from said fabric.
6. The method claimed in claim 1 further comprising separating said garments from said aqueous solution of 1-hydroxy ethylidene-1, 1-diphosphonic acid before subjecting said garments to said alkaline detergent solution.