Charge Director for Liquid Toner

Abstract

A charge director material for charging a liquid toner, the charge director material comprising (a) nanoparticles of a simple salt and (b) a sulfosuccinate salt of the general formula MA n , wherein M is a metal, n is the valence of M, and A is an ion of the general formula (I) [R 1 —O—C(O)CH 2 CH(SO 3 − )C(O)—O—R 2 ],  (I) wherein each of R 1 and R 2 is an alkyl group; said charge director material being substantially free of acids of the general formula (I), wherein one or both of R1 and R2 is hydrogen, and if only one of them is hydrogen, the other is an alkyl group,

1 . A charge director material for charging a liquid toner the charge director material comprising:
 (a) nanoparticles of a simple salt;   (b) a first micelle forming substance, being sulfosuccinate salt of the general formula MA n , wherein M is a metal, n is the valence of M, and A is an ion of the general formula (I)
   [R 1 —O—C(O)CH 2 CH(SO 3 —)C(O)—O—R 2 ],  (I) 
   wherein each of R 1  and R 2  is an alkyl group; and   (c) a second micelle forming substance.   
     
     
         2 . A charge director material according to  claim 1 , wherein the second micelle forming compound is basic barium petronate. 
     
     
         3 . A charge director material according to  claim 1 , which is substantially free of an acid having a general formula HA. 
     
     
         4 . A charge director material according to  claim 1 , comprising micelles of said sulfosuccinate salt enclosing said nanoparticles. 
     
     
         5 . A charge director material according to  claim 1 , wherein said nanoparticles are of average size 200 nm or less. 
     
     
         6 . A charge director material according to  claim 1 , wherein said nanoparticles are of average size 2 nm or more. 
     
     
         7 . A charge director material according to  claim 1 , wherein said simple salt is BaSO 4  or BaHPO4. 
     
     
         8 . A method for obtaining a material comprising (i) nanoparticles of a simple salt and (ii) a sulfosuccinate salt of the general formula MA n , wherein M is a metal, n is the valence of M, and A is an ion of the general formula (I)
   [R 1 —O—C(O)CH 2 CH(SO 3 —)C(O)—O—R 2 ],  (I)   wherein each of R 1  and R 2  is an alkyl group;   
       the method comprising:
 (a) providing a sulfosuccinate salt of the general formula M′A n′ , M′ being a metal other than the metal M and n′ being the valence of M′, 
 (b) adding strong acid as to obtain an acid HA; and 
 (c) adding a strong base as to neutralize 30-85%. 
 
     
     
         9 . A method according to  claim 8 , wherein the strong base is added to neutralize 50-80% of acids. 
     
     
         10 . A method according to  claim 8 , further comprising:
 (d) evaporating solvents to obtain the material in solid form, and performing an aqueous workup on the solid obtained.   
     
     
         11 . A method according to  claim 8 , further comprising:
 (d) filtering to obtain solid product, and performing an aqueous workup on the solid obtained.   
     
     
         12 . A method according to  claim 8 , wherein said strong acid has at least one proton with a pK a  smaller than 1. 
     
     
         13 . A method for obtaining a chemical material of the general formula M p X q @MA n  in a reaction mixture, wherein M is a metal, X is an anion, n is the valence of M, and p and q are coefficients that ensures that M p X q  is electrically balanced, and A is a compound of the general formula (I)
   [R 1 —O—C(O)CH 2 CH(SO 3 —)C(O)—O—R 2 ],  (I)   wherein R 1  and R 2  are alkyl groups,   
       the method comprising:
 (a) providing a sulfosuccinate salt of the general formula M′A n′ , wherein M′ is a metal other than M and n′ the valence of M′; 
 (b) adding a strong acid, having at least one pK a  smaller than 1, to obtain a first reaction mixture containing a sulfonic acid of the general formula HA; 
 (c) working up the obtained reaction mixture to obtain substantially pure HA; and 
 (d) adding a predetermined amount of base M(OH) n , in the presence of an ionic substance, as to obtain a second reaction mixture containing a chemical material of the general formula M p X q @MA n . 
 
     
     
         14 . A method according to  claim 13 , wherein the predetermined amount of base is such that the obtained chemical material is substantially free of acids of the general formula (I), wherein one or both of R 1  and R 2  is hydrogen, and if only one of them is hydrogen, the other is an alkyl group. 
     
     
         15 . A method according to  claim 13 , wherein said predetermined amount of base is from 30% to 85% of an amount required to obtain a neutral second reaction mixture. 
     
     
         16 . A method according to  claim 13 , wherein the strong acid is H 2 SO 4 . 
     
     
         17 . A method according to  claim 13 , wherein said ionic substance is an acid. 
     
     
         18 . A method according to  claim 13 , wherein in (b) substantially all the sulfosuccinate salt is converted to acid. 
     
     
         19 . A method according to  claim 13 , also comprising reacting remaining acid HA with a non hydroxyl base. 
     
     
         20 . A method according to  claim 19 , wherein the non-hydroxyl base is triethyl amine, barium isopropoxide, aluminum isopropoxide or mixture thereof.