Cleaning system utilizing an organic cleaning solvent and a pressurized fluid solvent

Abstract

A cleaning system that utilizes an organic cleaning solvent and pressurized fluid solvent is disclosed. The system has no conventional evaporative hot air drying cycle. Instead, the system utilizes the solubility of the organic solvent in pressurized fluid solvent as well as the physical properties of pressurized fluid solvent. After an organic solvent cleaning cycle, the solvent is extracted from the textiles at high speed in a rotating drum in the same way conventional solvents are extracted from textiles in conventional evaporative hot air dry cleaning machines. Instead of proceeding to a conventional drying cycle, the extracted textiles are then immersed in pressurized fluid solvent to extract the residual organic solvent from the textiles. This is possible because the organic solvent is soluble in pressurized fluid solvent. After the textiles are immersed in pressurized fluid solvent, pressurized fluid solvent is pumped from the drum. Finally, the drum is de-pressurized to atmospheric pressure to evaporate any remaining pressurized fluid solvent, yielding clean, solvent free textiles. The organic solvent is preferably selected from terpenes, halohydrocarbons, certain glycol ethers, polyols, ethers, esters of glycol ethers, esters of fatty acids and other long chain carboxylic acids, fatty alcohols and other long-chain alcohols, short-chain alcohols, polar aprotic solvents, siloxanes, hydrofluoroethers, dibasic esters, and aliphatic hydrocarbons solvents or similar solvents or mixtures of such solvents and the pressurized fluid solvent is preferably densified carbon dioxide.

1. A process for removing contaminants from one or more substrates that comprise contaminants, the process comprising steps of:
 (a) placing the one or more substrates in a rotatable cleaning unit;  
 (b) placing the rotatable cleaning unit in a pressurizable vessel;  
 (c) adding organic solvent to at least one of the vessel and the cleaning unit;  
 (d) imparting movement of the cleaning unit under substantially non-pressurized conditions;  
 (e) removing a first portion of the organic solvent from the vessel;  
 (f) pressurizing the vessel;  
 (g) adding pressurized fluid solvent to the vessel to form an organic solvent-pressurized fluid solvent mixture;  
 (h) removing at least a portion of the mixture from the pressurized vessel;  
 (i) depressurizing the vessel to form vaporized fluid solvent and substantially dry, clean one or more substrates; and  
 (j) removing at least a portion of the dry, clean one or more substrates from the vessel; wherein:  
 steps (a)-(b) occur in any order or substantially simultaneously.  
 
     
     
       2. The process of  claim 1  wherein the rotatable cleaning unit is perforated. 
     
     
       3. The process of  claim 2  wherein the rotatable cleaning unit is selected from the group consisting of a drum and a wheel. 
     
     
       4. The process of  claim 1  wherein step (b) occurs prior to step (a). 
     
     
       5. The process of  claim 1  further comprising a step of adding at least one additive to the organic solvent prior to, during or immediately after step (c). 
     
     
       6. The process of  claim 5  wherein the at least one additive is selected to enhance removal of the contaminants from the one or more substrates. 
     
     
       7. The process of  claim 5  wherein the at least one additive is selected to enhance cleaning of the process. 
     
     
       8. The process of  claim 1  further comprising a step of adding at least one additive to the vessel prior to step (c). 
     
     
       9. The process of  claim 1  wherein step (d) further comprises cycling at least a portion of the organic solvent from the vessel and through a filtration assembly to form filtered organic solvent, and reintroducing the filtered organic solvent into the vessel. 
     
     
       10. The process of  claim 9  wherein said filtration assembly comprises a filter selected from the group consisting of a mesh filter, an absorption filter and an adsorption filter. 
     
     
       11. The process of  claim 1  wherein the movement in step (d) comprises agitation. 
     
     
       12. The process of  claim 1  wherein the movement in step (d) comprises rotation. 
     
     
       13. The process of  claim 12  further comprising a step of separating contaminants from the first portion of organic solvent upon removal of said first portion of organic solvent from the vessel in step (e). 
     
     
       14. The process of  claim 2  wherein removing step (h) is performed by pumping a portion of the mixture away from the vessel. 
     
     
       15. The process of  claim 14  wherein after step (h) but prior to step (i), the cleaning unit is rotated to remove a remaining portion of mixture from the at least one substrate. 
     
     
       16. The process of  claim 15  wherein the unit is rotated at a rate of about 150 to about 800 rpm. 
     
     
       17. The process of  claim 1  further comprising a step of collecting at least a portion of the vaporized fluid solvent formed in step (i) and compressing it for subsequent use as pressurized fluid solvent. 
     
     
       18. The process of  claim 1  further comprising repeating steps (g) and (h) one or more times prior to performing said step (i). 
     
     
       19. The process of  claim 1  further comprising a step of spot treating the substrates prior to step (a). 
     
     
       20. The process of  claim 1  wherein the substrates comprise textiles. 
     
     
       21. The process of  claim 1  wherein the pressurized fluid solvent is inorganic. 
     
     
       22. The process of  claim 1  wherein the pressurized fluid solvent comprises a compound selected from the group consisting of carbon dioxide, xenon, nitrous oxide and sulfur hexafluoride. 
     
     
       23. The process of  claim 1  wherein the pressurized fluid solvent comprises liquid, supercritical or subcritical carbon dioxide. 
     
     
       24. The process of  claim 1  wherein the organic solvent has a flash point, if any, of at least about 100° F. 
     
     
       25. The process of  claim 1  wherein the organic solvent is soluble in the pressurized fluid solvent. 
     
     
       26. The process of  claim 1  wherein the organic solvent comprises a compound of formula C a X j H k O z , wherein:
 a=5n and 1≦n≦3;  
 each X is independently F, Cl, Br or I;  
 0≦z≦4;  
 0≦j≦10;  
 0≦k 10; and  
 0≦(j+k)≦10n.  
 
     
     
       27. The process of  claim 1  wherein the organic solvent comprises a compound of formula C n X j H k  wherein:
 1≦n≦20;  
 each X is independently F, Cl, Br or I;  
 0≦j;  
 k≦2n+2; and  
 2n−4≦(j+k)≦2n+2.  
 
     
     
       28. The process of  claim 1  wherein the organic solvent comprises a compound of formula 
                 
 R iv =C j H u X v ;  
 R ii =C k H y X z  or benzyl, phenyl, partially or fully fluorinated benzyl or phenyl;  
 0≦u, v≦2j+1;  
 0≦(u+v)≦2j+1;  
 0≦y,z≦2k+1;  
 0≦(y+z)≦2k+1;  
 0≦u,v,y,z≦37;  
 R 1-4  and R 9-12  are independently C m H n X p , 
 where 0≦m≦2;  
 0≦(n+p)≦5; and  
 n+p=2m+1;  
 
 R 5-8  and R 13-16  are independently C a H b X d , 
 wherein a is 0 or 1;  
 0≦(b+d)≦3; and  
 b+d=2a+1; and  
 
 each X is independently F, Cl, Br or I.  
 
     
     
       29. The process of  claim 1  wherein the organic solvent comprises a compound of formula 
                 
 R iv =C j H u X v ;  
 R ii =C k H y X z  or benzyl, phenyl, partially or fully fluorinated benzyl or phenyl;  
 j and k each equal 0 independently or  
 14−3(x+y+z)≦j≦22−3(x+y+z);  
 14−3(x+y+z)≦k≦22−3(x+y+z) and  
 14−3(x+y+z)≦(j+k)≦22−3(x+y+z);  
 0≦x,y,z≦1;  
 0≦(x+y+z)≦3;  
 0≦u,v,y,z≦37;  
 0≦(u+v)≦2j+1;  
 0≦(y+z)≦2k+1;  
 R 1-3  and R 7-9  are independently C m H n X p , 
 where 0≦m≦2;  
 0≦(n+p)≦5; and  
 n+p=2m+1;  
 R 4-6  and R 10-12  are independently C a H b X d ,  
 wherein a is 0 or 1;  
 0≦(b+d)≦3; and  
 b+d=2a+1; and  
 
 each X is independently F, Cl, Br or I.  
 
     
     
       30. The process of  claim 1  wherein the organic solvent comprises a compound of formula C n H j X k (OH) r  wherein:
 each X is independently F, Cl, Br or I;  
 1≦n≦20;  
 0≦r≦4;  
 0≦j≦2n+2−r;  
 0≦k≦2n+2−r; and  
 2n−4−r≦(j+k)≦2n+2−r.  
 
     
     
       31. The process of  claim 1  wherein the organic solvent comprises a compound of formula C n H j X k   0   b  wherein:
 each X is independently F, Cl, Br or I;  
 2≦n≦20;  
 0≦j≦2n+2;  
 0≦k≦2n+2;  
 2n−4≦(j+k)≦2n+2; and  
 1≦b≦6.  
 
     
     
       32. The process of  claim 1  wherein the organic solvent comprises a compound of formula 
                 
 R v =C j H u X v ;  
 R ii =C k H a X b ;  
 15≦j,k≦32−3(w+x+y+z);  
 15≦j+k≦32−3(w+x+y+z);  
 0≦u,v≦2j+1;  
 0≦a;  
 b2k+1;  
 2j−7≦(u+v)≦2j+1;  
 2k−7≦(y+z)≦2k+1; and  
 R 1-4  and R 9-12  are independently C m H n X p , 
 wherein 0≦m≦2;  
 0≦(n+p)≦5; and  
 n+p=2m+1;  
 
 R 5-8  and R13-16 are independently C a H b X d , 
 wherein a is 0or 1;  
 0≦(b+d)≦3; and  
 b+d=2a+1; and  
 
 each X is independently F, Cl, Br or I.  
 
     
     
       33. The process of  claim 1  wherein the organic solvent is of the structural formula: 
                 
 R iv =C j H u X v ;  
 R v =C j H u X v ;  
 R ii =C k H a X b ;  
 15≦j,k≦32−3(w+x+y+z);  
 15≦j+k≦32−3(w+x+y+z);  
 0≦u,v≦2j+1;  
 0≦a;  
 b≦2k+1;  
 2j−7≦(u+v)≦2j+1;  
 2k−7≦(y+z)≦2k+1; and  
 R 1-4  and R 9-12  are independently C m H n X p , 
 wherein 0≦m≦2;  
 0≦(n+p)≦5; and  
 n+p=2m+1;  
 
 R 5-8  and R 13-16  are independently C a H b X d , 
 wherein a is 0 or 1;  
 0≦(b+d)≦3; and  
 b+d=2a+1; and  
 
 each X is independently F, Cl, Br or I.  
 
     
     
       34. The process of  claim 1  wherein the organic solvent is of the structural formula: C n (CO 2 ) m H a X b  
 wherein:  
 each X is independently F, Cl, Br or I;  
 2≦n≦21;  
 1≦m≦3;  
 0≦a;  
 b≦2n+2; and  
 2n−2≦(a+b)≦2n+z.  
 
     
     
       35. The process of  claim 1  wherein the organic solvent is of the structural formula: C n (C 03 ) m H a X b  
 wherein: 
 each X is independently F, Cl, Br or I;  
 2≦n≦18;  
 m=1;  
 0≦a;  
 
 b≦2n+2; and  
 2n−4≦(a+b)≦2n+z.  
 
     
     
       36. The process of  claim 1  wherein the organic solvent is of the structural formula: 
                 
 wherein: 
 R l =C j H a X b  
 1≦j≦6  
 0≦a;  
 b≦2j+1; and  
 2j−7≦(a+b)≦2j+1;  
 
 R 2 =C k H d X e  
 1≦k≦6;  
 0≦d;  
 e≦2k+1; and  
 d+e=2k+1;  
 
 R 3 =C m H e X f  
 1≦m≦6;  
 
 0≦e; 
 f≦2m+1; and  
 e+f=2m+1; and  
 
 each X is independently F, Cl, Br or I.  
 
 
     
     
       37. The process of  claim 1  wherein the organic solvent is of the structural formula: SO e C n H j X k  
 wherein: 
 each X is independently F, Cl, Br or I;  
 1≦e≦2;  
 2≦n≦8;  
 0≦j;  
 k≦2a+1; and  
 2n≦(j+k)≦2n+1.  
 
 
     
     
       38. The process of  claim 1  wherein the organic solvent is of the structural formula: C n H y N a O b  
 wherein: 
 1≦n≦10;  
 1≦a;  
 b≦2 and a=b; and  
 2n−1≦y≦2n+1.  
 
 
     
     
       39. The process of  claim 1  wherein the organic solvent is of the structural formula: 
                 
 wherein:  
 each R equals C a X y H z  independently;  
 each X is independently F, Cl, Br or I;  
 1≦a≦3; and  
 0≦y,z≦2a+1 and y+z=2a+1.  
 
     
     
       40. The process of  claim 1  wherein the organic solvent is of the structural formula: 
                 
 wherein: 
 2≦n≦4;  
 each R equals C a H y X z  independently;  
 each X is independently F, Cl, Br or I;  
 1≦n≦3  
 0y;  
 z≦2a+1 and y+z=2a+1.