Water-miscible metal working fluids with reduced aerosol inhalation toxicity

Abstract

The present invention provides a process for producing a water-miscible metalworking fluid involving combining about 90 wt. % to about 5 wt. %, based on the weight of the fluid, of water and one or more additives chosen from plasticizers, chelating agents, biocides, surfactants, dispersants, dyes, odorants, extreme pressure agents, anti-oxidants and corrosion inhibitors with about 10 wt. % to about 95 wt. %, based on the weight of the fluid, of a polyether polyol produced by mixing an active hydrogen compound with a double metal cyanide (DMC) catalyst in a reactor vessel, charging to the reactor vessel a mixture containing two or more alkylene oxides to activate the catalyst, and continuously feeding one or more alkylene oxides to produce the polyether polyol, wherein a 1% solution in water of the polyether polyol has a cloud point of from greater than about 32° C. to less than about 53° C., the polyether polyol has a number average equivalent weight of from greater than about 1,600 Da to about 10,000 Da, and a four-hour aerosol inhalation exposure to the polyether polyol has a LC 50 of greater than about 5 mg/L. The water-miscible metalworking fluid produced by the inventive process may find use in cooling and/or lubricating metal surfaces during one or more of grinding, cutting, boring, drilling and turning of metal parts.

1 . A process for producing a water-miscible metalworking fluid comprising combining: 
 about 90 wt. % to about 5 wt. %, based on the weight of the fluid, of water; and    one or more additives chosen from plasticizers, chelating agents, biocides, surfactants, dispersants, dyes, odorants, extreme pressure agents, anti-oxidants and corrosion inhibitors; with    about 10 wt. % to about 95 wt. %, based on the weight of the fluid of a polyether polyol produced by 
 mixing an active hydrogen compound with a double metal cyanide (DMC) catalyst in a reactor vessel,  
 charging to the reactor vessel a mixture containing two or more alkylene oxides to activate the catalyst, and  
 continuously feeding one or more alkylene oxides to produce the polyether polyol,  
 wherein a 1% solution in water of the polyether polyol has a cloud point of from greater than about 32° C. to less than about 53° C., the polyether polyol has a number average equivalent weight of from greater than about 1,600 Da to about 10,000 Da, and a four-hour aerosol inhalation exposure to the polyether polyol has a LC 50  of greater than about 5 mg/L.  
   
   
   
       2 . The process according to  claim 1 , wherein the active hydrogen compound is chosen from methanol, ethanol, propanol, butanol, pentanol, phenols, C 6 -C 36  branched or linear alcohols, monofunctional ethers of polypropylene glycols, polyethylene glycols, polybutylene glycols, polyoxyalkylene glycol copolymers, water, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, propanediol, glycerine, trimethylolpropane, butanediol isomers, pentaerythritol, polypropylene glycols, polyethylene glycols, polybutylene glycols and polyoxyalkylene glycol copolymers.  
   
   
       3 . The process according to  claim 1 , wherein the active hydrogen compound is butanol.  
   
   
       4 . The process according to  claim 1 , wherein the DMC catalyst is a zinc hexacyanocobaltate.  
   
   
       5 . The process according to  claim 1 , wherein the mixture contains two or more alkylene oxides chosen from ethylene oxide, propylene oxide, 1,2- and and 2,3-butylene oxide, isobutylene oxide, epichlorohydrin, cyclohexene oxide, styrene oxide and C 5 -C 30  α-alkylene oxides.  
   
   
       6 . The process according to  claim 1 , wherein the continuous feeding is of one or more alkylene oxides chosen from ethylene oxide, propylene oxide, 1,2- and 2,3-butylene oxide, isobutylene oxide, epichlorohydrin, cyclohexene oxide, styrene oxide and C 5 -C 30  α-alkylene oxides.  
   
   
       7 . The process according to  claim 1 , wherein the water-miscible metalworking fluid comprises from about 40 wt. % to about 90 wt. %, based on the weight of the fluid, of the polyether polyol and from about 60 wt. % to about 10 wt. %, based on the weight of the fluid, of water.  
   
   
       8 . The process according to  claim 1 , wherein the polyether polyol has a number average equivalent weight of from about 1,600 Da to about 6,000 Da.  
   
   
       9 . The water-miscible metalworking fluid produced by the process according to  claim 1 .  
   
   
       10 . A process for producing a water-miscible metalworking fluid comprising combining: 
 about 90 wt. % to about 5 wt. %, based on the weight of the fluid, of water; and    one or more additives chosen from plasticizers, chelating agents, biocides, surfactants, dispersants, dyes, odorants, extreme pressure agents, anti-oxidants and corrosion inhibitors; with    about 10 wt. % to about 95 wt. %, based on the weight of the fluid, of a polyether polyol produced by 
 mixing with a double metal cyanide (DMC) catalyst in a reactor vessel an initiator chosen from one or more of a polyol from a prior preparation (heel) having an equivalent weight greater than about 300 Da, a lower molecular weight active hydrogen compound that does not deactivate the DMC catalyst and an inert solvent,  
 charging to the reactor vessel a mixture containing two or more alkylene oxides to activate the catalyst, and  
 continuously feeding one or more alkylene oxides and one or more starters to produce the polyether polyol,  
 wherein a 1% solution in water of the polyether polyol has a cloud point of from greater than about 32° C. to less than about 53° C., polyether polyol has a number average equivalent weight of from greater than about 1,600 Da to about 10,000 Da, and a four-hour aerosol inhalation exposure to the polyether polyol has a LC 50  of greater than about 5 mg/L.  
   
   
   
       11 . The process according to  claim 10 , wherein the initiator is a polyol from a prior preparation (heel) having an equivalent weight greater than about 300 Da.  
   
   
       12 . The process according to  claim 10 , wherein the initiator is a lower molecular weight active hydrogen compound that does not deactivate the DMC catalyst.  
   
   
       13 . The process according to  claim 10 , wherein the initiator is an inert solvent.  
   
   
       14 . The process according to  claim 10 , wherein the DMC catalyst is a zinc hexacyanocobaltate.  
   
   
       15 . The process according to  claim 10 , wherein the mixture contains two or more-alkylene oxides chosen from ethylene oxide, propylene oxide, 1,2- and 2,3-butylene oxide, isobutylene oxide, epichlorohydrin, cyclohexene oxide, styrene oxide and C 5  -C 30  α-alkylene oxides.  
   
   
       16 . The process according to  claim 10 , wherein the continuous feeding is of one or more alkylene oxides chosen from ethylene oxide, propylene oxide, 1,2- and 2,3-butylene oxide, isobutylene oxide, epichlorohydrin, cyclohexene oxide, styrene oxide and C 5 -C 30  α-alkylene oxides.  
   
   
       17 . The process according to  claim 10 , wherein the starter is chosen from methanol, ethanol, propanol, butanol, pentanol, phenols, C 6 -C 36  branched or linear alcohols, monofunctional ethers of polypropylene glycols, polyethylene glycols, polybutylene glycols, polyoxyalkylene glycol copolymers, water, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, propanediol, glycerine, trimethylolpropane, butanediol isomers, polypropylene glycols, polyethylene glycols, polybutylene glycols and polyoxyalkylene glycol copolymers.  
   
   
       18 . The process according to  claim 10 , wherein the starter is butanol.  
   
   
       19 . The process according to  claim 10 , wherein the water-miscible metalworking fluid comprises from about 40 wt. % to about 90 wt. %, based on the weight of the fluid, of the polyether polyol and from about 60 wt. % to about 10 wt. %, based on the weight of the fluid, of water.  
   
   
       20 . The water-miscible metalworking fluid produced by the process according to  claim 10.