Boron-free water-based lubricant for plastic working

Abstract

The present disclosure is directed to an aqueous lubricating composition comprising, based on the weight of the composition: from 1 to 20 wt. % of a) at least one water-soluble inorganic salt, said inorganic salt or salts being in a dissolved state; b) at least one particulate solid lubricant; from 0.1 to 5 wt. % of c) at least one rheological control agent; from 0.1 to 5 wt. % of d) at least one base; and, from 0.1 to 5 wt. % of e) at least one surfactant selected from the group consisting of anionic surfactants, nonionic surfactants, cationic surfactants, amphoteric surfactants and zwitterionic surfactants, wherein said composition is free from boron and boron compounds and is further characterized in that the ratio by weight of b) said at least one solid lubricant to a) said at least one water-soluble inorganic salt [(b):(a)] is from 0.1:1 to 1:1.

1 . An aqueous lubricating composition comprising, based on the weight of the composition:
 from 1 to 20 wt. % of a) at least one water-soluble inorganic salt, said inorganic salt or salts being in a dissolved state;   b) at least one particulate solid lubricant;   from 0.1 to 5 wt. % of c) at least one rheological control agent;   from 0.1 to 5 wt. % of d) at least one base; and,   from 0.1 to 5 wt. % of e) at least one surfactant selected from the group consisting of anionic surfactants, nonionic surfactants, cationic surfactants, amphoteric surfactants and zwitterionic surfactants,   wherein said composition is free from boron and boron compounds and has a ratio by weight of b) said at least one solid lubricant to a) said at least one water-soluble inorganic salt [(b):(a)] of from 0.1:1 to 1:1.   
     
     
         2 . The aqueous lubricating composition according to  claim 1  comprising, based on weight of the composition
 from 2 to 20 wt. % of a) said at least one water-soluble inorganic salt; 
 b) said least one particulate solid lubricant; 
 from 0.1 to 2.5 wt. % of c) said least one rheological control agent; 
 from 0.1 to 2.5 wt. % of d) said least one base; and, 
 from 0.1 to 2.5 wt. % of e) said at least one surfactant selected from the group consisting of anionic surfactants, nonionic surfactants, cationic surfactants, amphoteric surfactants and zwitterionic surfactants, 
 wherein the ratio by weight of b) said at least one solid lubricant to a) said at least one water-soluble inorganic salt [(b):(a)] is from 0.2:1 to 1:1. 
 
     
     
         3 . The aqueous lubricating composition according to  claim 1  comprising from 60 to 90 wt. % of water, based on the weight of the composition. 
     
     
         4 . The aqueous lubricating composition according to  claim 1 , wherein the composition has a viscosity of from 0.005 to 1 Pa·s, as measured using a Brookfield viscometer at 25° C. 
     
     
         5 . The aqueous lubricating composition according to  claim 1 , wherein total amount of c) the at least one rheological control agent(s) present in the composition is from 1 to 10 wt. % of the total amount by weight of components a) and b). 
     
     
         6 . The aqueous lubricating composition according to  claim 1  having a pH of from 7 to 10. 
     
     
         7 . The aqueous lubricating composition according to  claim 1 , wherein component a) comprises a mixture of sodium sulphate, potassium tripolyphosphate and sodium tripolyphosphate. 
     
     
         8 . The aqueous lubricating composition according to  claim 1 , wherein the or each solid particulate lubricant included in the composition has a dso particle size of less than 5 microns, as measured by laser diffraction. 
     
     
         9 . The aqueous lubricating composition according to  claim 1 , wherein said component b) comprises:
 at least one phosphate salt selected from the group consisting of zinc phosphate, zinc calcium phosphate and manganese phosphate; and,   at least one wax selected from the group consisting of: polyethylene waxes; oxidized polyethylene waxes; polypropylene waxes; oxidized polypropylene waxes; and, co-polymeric waxes based on ethylene or propylene as the majority monomers,   and wherein said at least one wax has a number average molecular weight (Mn) of from 400 to 30,000 g/mol.   
     
     
         10 . The aqueous lubricating composition according to  claim 1 , wherein c) said at least one rheological control agent is selected from the groups consisting of: cellulose derivatives; and, polysaccharides. 
     
     
         11 . The aqueous lubricating composition according to  claim 10 , wherein component c) comprises carboxymethycellulose (CMC) and xanthan gum. 
     
     
         12 . The aqueous lubricating composition according to  claim 1 , wherein d) said at least one base is selected from the group consisting of: bis(2-(N,N′-dimethylamino)ethyl)ether; bis-(t-butylaminoethyl)ether, 1,2-bis-(t-butylaminoethoxy)ethane; 1,2-bis-(t-butylaminoethoxyethoxy) ethane; bis[2-(isopropylamino)propyl]ether; 1,2-[2-isopropylamino)-propoxy]ethane. 
     
     
         13 . The aqueous lubricating composition according to  claim 12 , wherein component d) comprises or consists of bis(2-(N,N′-dimethylamino)ethyl)ether. 
     
     
         14 . A method of plastic cold working of metallic substrates comprising applying or applying and drying the aqueous waterborne lubricating composition of  claim 1 . 
     
     
         15 . A process for plastic cold working of a solid metallic substrate by mechanically forcing said solid metallic substrate through an aperture bounded by at least one solid surface of at least one metal working tool, said process comprising the steps of:
 (i) applying the aqueous lubricating composition of  claim 1  to a solid surface of said solid metallic substrate that would, if not coated, directly contact a solid metal working tool surface during the process;   (ii) drying the applied aqueous lubricating composition to form a film on said at least one solid surface of said metallic substrate; and   (iii) mechanically forcing the metallic substrate formed in step ii) through said aperture bounded by the at least one metal working tool surface, so that the metallic substrate is cold worked.