Nickel (II) salts as charging adjuvants for electrostatic liquid developers

Claim 2

An electrostatic liquid developer having improved charging characteristics consisting essentially of (A) a nonpolar liquid having a Kauri-butanol value of less than 30, present in a major amount, (B) thermoplastic resin particles having dispersed therein a nickel (II) salt, the resin particles having an average particle size of less than 30 μm, and (C) a nonpolar liquid soluble honhc or zwitterionic charge director compound.

Claim 3

An electrostatic liquid developer according to claim 1 wherein the nickel (II) salt anion is selected from the group consisting of chloride, fluoride, phosphate, sulfate, acetate, hydroxide, nitrate, carbonate, benzenesulfonate, benzoate, citrate, cyanide, formate, oxalate, and sulfamate.

Claim 4

An electrostatic liquid developer according to claim 2 wherein the nickel II salt is nickel chloride.

Claim 5

An electrostatic liquid developer according to claim 3 wherein the nickel (II) salt is NiCl 2 .6H 2 O.

Claim 6

An electrostatic liquid developer according to claim 2 wherein the nickel (II) salt is nickel carbonate.

Claim 7

An electrostatic liquid developer according to claim 2 wherein the nickel (II) salt is nickel hydroxide.

Claim 8

An electrostatic liquid developer according to claim 1 wherein component (A) is present in 85 to 99.9% by weight, based on the total weight of liquid developer, the total weight of developer solids is 0.1 to 15.0% by weight, and component (C) is present in an amount of 0.25 to 1500 mg/g developer solids.

Claim 9

An electrostatic liquid developer according to claim 7 wherein the nickel (II) salt is present in 0.1 to 40% by weight based on the total weight of the developer solids.

Claim 10

An electrostatic liquid developer according to claim 1 containing up to about 60% by weight of a colorant based on the total weight of developer solids.

Claim 11

An electrostatic liquid developer according to claim 9 wherein the colorant is a pigment.

Claim 12

An electrostatic liquid developer according to claim 9 wherein the colorant is a dye.

Claim 13

An electrostatic liquid developer according to claim 1 wherein a fine particle size oxide is present.

Claim 14

An electrostatic liquid developer according to claim 1 wherein an additional compound is present which is an adjuvant selected from the group consisting of polyhydroxy compound, aminoalcohol, polybutylene succinimide, metallic soap, and an aromatic hydrocarbon.

Claim 15

An electrostatic liquid developer according to claim 9 wherein an additional compound is present which is an adjuvant selected from the group consisting of polyhydroxy compound, aminoalcohol, polybutylene succinimide, metallic soap, and an aromatic hydrocarbon.

Claim 16

An electrostatic liquid developer according to claim 13 wherein a polyhydroxy adjuvant compound is present.

Claim 17

An electrostatic liquid developer according to claim 13 wherein an aminoalcohol adjuvant compound is present.

Claim 18

An electrostatic liquid developer according to claim 13 wherein a polybutylene succinimide adjuvant compound is present.

Claim 19

An electrostatic liquid developer according to claim 13 wherein a metallic soap adjuvant compound is present dispersed in the thermoplastic resin.

Claim 20

An electrostatic liquid developer according to claim 13 wherein an aromatic hydrocarbon adjuvant compound having a Kauri-butanol value of greater than 30 is present.

Claim 21

An electrostatic liquid developer according to claim 16 wherein the aminoalcohol adjuvant compound is triisopropanolamine.

Claim 22

An electrostatic liquid developer according to claim 1 wherein the thermoplastic resin is a copolymer of ethylene and an α,β-ethylenically unsaturated acid selected from the group consisting of acrylic acid and methacrylic acid.

Claim 23

An electrostatic liquid developer according to claim 1 wherein the thermoplastic resin is polystyrene.

Claim 24

An electrostatic liquid developer according to claim 1 wherein the thermoplastic resin is a copolymer of ethylene (80 to 99.9%)/acrylic or methacrylic acid (20 to 0%)/alkyl ester of acrylic or methacrylic acid wherein alkyl is 1 to 5 carbon atoms (0 to 20%).

Claim 25

An electrostatic liquid developer according to claim 9 wherein the thermoplastic resin is a copolymer of ethylene (80 to 99.9%)/acrylic or methacrylic acid (20 to 0%)/alkyl ester of acrylic or methacrylic acid wherein alkyl is 1 to 5 carbon atoms (0 to 20%).

Claim 26

An electrostatic liquid developer according to claim 23 wherein the thermoplastic resin is a copolymer of ethylene (89%)/methacrylic acid (11%) having a melt index at 190° C. of 100.

Claim 27

An electrostatic liquid developer according to claim 1 wherein the particles have an average particle size of less than 15 μm.

Claim 28

An electrostatic liquid developer according to claim 1 wherein component (C) is an oil-soluble petroleum sulfonate.

Claim 29

An electrostatic liquid developer according to claim 1 wherein component (C) is a sodium salt of phosphated mono- and diglycerides with unsaturated or saturated acid substituents.

Claim 30

A process for preparing electrostatic liquid developer for electrostatic imaging comprising (A) dispersing at an elevated temperature in a vessel a thermoplastic resin, a nickel (II) salt, a dispersant nonpolar liquid having a Kauri-butanol value of less than 30, while maintaining the temperature in the vessel at a temperature sufficient to plasticize and liquify the resin and below that at which the dispersant nonpolar liquid degrades and the resin decomposes, (B) cooling the dispersion, either (1) without stirring to form a gel or solid mass, followed by shredding the gel or solid mass and grinding by means of particulate media with or without the presence of additional liquid; (2) with stirring to form a viscous mixture and grinding by means of particulate media with or without the presence of additional liquid; or (3) while grinding by means of particulate media to prevent the formation of a gel or solid mass with or without the presence of additional liquid; (C) separating the dispersion of toner particles having an average particle size of less than 30 μm from the particulate media, and (D) adding to the dispersion a nonpolar liquid soluble ionic or zwitterionic charge director compound.

Claim 31

A process for preparing electrostatic liquid developer for electrostatic imaging comprising (A) dispersing at an elevated temperature in a vessel a thermoplastic resin, a nickel (II) salt, a dispersant nonpolar liquid having a Kauri-butanol value of less than 30, while maintaining the temperature in the vessel at a temperature sufficient to plasticize and liquify the resin and below that at which the dispersant nonpolar liquid degrades and the resin decomposes, (B) cooling the dispersion, either (1) without stirring to form a gel or solid mass, followed by shredding the gel or solid mass and grinding by means of particulate media with or without the presence of additional liquid; (2) with stirring to form a viscous mixture and grinding by means of particulate media with or without the presence of additional liquid; or (3) while grinding by means of particulate media to prevent the formation of a gel or solid mass with or without the presence of additional liquid; (C) separating the dispersion of toner particles having an average particle size of less than 30 μm from the particulate media, and (D) adding to the dispersion a nonpolar liquid soluble ionic or zwitterionic charge director compound.

Claim 32

A process according to to claim 29 wherein the nickel (II) salt anion is selected from the group consisting of chloride, fluoride, phosphate, sulfate, acetate, hydroxide, nitrate, carbonate, benzenesulfonate, benzoate, citrate, cyanide, formate, oxalate, and sulfamate.

Claim 33

A process according to claim 30 wherein the nickel (II) salt is nickel chloride.

Claim 34

A process according to claim 31 wherein the nickel (II) salt is NiCl 2 .6H 2 O.

Claim 35

A process according to claim 30 wherein the nickel (II) salt is nickel carbonate.

Claim 36

A process according to claim 30 wherein the nickel (II) salt is nickel hydroxide.

Claim 37

A process according to claim 29 wherein there is present in the vessel up to 100% by weight of a polar liquid having a Kauri-butanol value of at least 30, the percentage based on the total weight of the developer liquid.

Claim 38

A process according to claim 29 wherein the particulate media are selected from the group consisting of stainless steel, carbon steel, ceramic, alumina, zirconia, silica and sillimanite.

Claim 39

A process according to claim 29 wherein the thermoplastic resin is a copolymer of ethylene and an α-β-ethylenically unsaturated acid selected from the group consisting of acrylic acid and methacrylic acid.

Claim 40

A process according to claim 29 wherein the thermoplastic resin is a copolymer of ethylene (80 to 99.9%)/acrylic or methacrylic acid (20 to 0%)/alkyl ester of acrylic or methacrylic acid wherein alkyl is 1 to 5 carbon atoms (0 to 20%).

Claim 41

A process according to claim 38 wherein the thermoplastic resin is a copolymer of ethylene (89%)/methacrylic acid (11%) having a melt index at 190° C. of 100.

Claim 42

A process according to claim 29 wherein the charge director compound is an oil-soluble petroleum sulfonate.

Claim 43

A process according to claim 29 wherein the charge director is a sodium salt of phosphated mono and diglycerides with unsaturated or saturated acid substituents.

Claim 44

A process according to claim 29 wherein additional dispersant nonpolar liquid, polar liquid, or combinations thereof is present to reduce the concentration of toner particles to between 0.1 to 15 percent by weight with respect to the developer liquid.

Claim 45

A process according to claim 42 wherein the concentration of toner particles is reduced by additional dispersant nonpolar liquid.

Claim 46

A process according to claim 29 wherein cooling the dispersion is accomplished while grinding by means of particulate media to prevent the formation of a gel or solid mass with or without the presence of additional liquid.

Claim 47

A process according to claim 29 wherein cooling the dispersion is accomplished without stirring to form a gel or solid mass, followed by shredding the gel or solid mass and grinding by means of particulate media with or without the presence of additional liquid.

Claim 48

A process according to claim 29 wherein cooling the dispersion is accomplished with stirring to form a viscous mixture and grinding by means of particulate media with or without the presence of additional liquid.

Claim 49

A process according to claim 29 wherein an adjuvant compound selected from the group consisting of polyhydroxy compound aminoalcohol, polybutylene succinimide, metallic soap, and an aromatic hydrocarbon is added during the dispersing step (A).

Claim 50

A process according to claim 47 wherein the adjuvant compound is an aminoalcohol.

Claim 51

A process according to claim 48 wherein the aminoalcohol is triisopropanolamine.

Claim 52

A process according to claim 42 wherein an adjuvant compound selected from the group consisting of polyhydroxy compound, aminoalcohol, polybutylene succinimide, metallic soap, and an aromatic hydrocarbon is added.

Claim 53

A process according to claim 50 wherein the adjuvant compound is a polyhydroxy compound.

Claim 54

A process according to claim 51 wherein the polyhydroxy compound is ethylene glycol.

Claim 55

A process according to claim 50 wherein the adjuvant compound is a metallic soap dispersed in the thermoplastic resin.

Claim 56

A process according to claim 53 wherein the metallic soap adjuvant compound is aluminium stearate dispersed in the thermoplastic resin.

Claim 57

A process for preparing electrostatic liquid developer comprising (A) dispersing a colorant and a nickel (II) metal salt in a thermoplastic resin in the absence of a dispersant nonpolar liquid having a Kauri-butanol value of less than 30 to form a solid mass, (B) shredding the solid mass, (C) grinding the shredded solid mass by means of particulate media in the presence of a liquid selected from the group consisting of a polar liquid having a Kauri-butanol value of at least 30, a nonpolar liquid having a Kauri-butanol value of less than 30, and combinations thereof, (D) separating the dispersion of toner particles having an average particle size of less than 30 μm from the particulate media, and (E) adding additional nonpolar liquid, polar liquid or combinations thereof to reduce the concentration of toner particles to between 0.1 to 15 percent by weight with respect to the liquid; and (F) adding to the dispersion a liquid soluble ionic or zwitterionic charge director compound.

Claim 58

A process for preparing electrostatic liquid developer comprising (A) dispersing a colorant and a nickel (II) metal salt in a thermoplastic resin in the absence of a dispersant nonpolar liquid having a Kauri-butanol value of less than 30 to form a solid mass, (B) shredding the solid mass, (C) grinding the shredded solid mass by means of particulate media in the presence of a liquid selected from the group consisting of a polar liquid having a Kauri-butanol value of at least 30, a nonpolar liquid having a Kauri-butanol value of less than 30, and combinations thereof, (D) separating the dispersion of toner particles having an average particle size of less than 30 μm from the particulate media, and (E) adding additional nonpolar liquid, polar liquid or combinations thereof to reduce the concentration of toner particles to between 0.1 to 15 percent by weight with respect to the liquid; and (F) adding to the dispersion a liquid soluble ionic or zwitterionic charge director compound.

Claim 59

A process for preparing electrostatic liquid developer comprising (A) dispersing a colorant and a nickel (II) salt in a thermoplastic resin in the absence of a dispersant nonpolar liquid having a Kauri-butanol value of less than 30 to form a solid mass, (B) shredding the solid mass, (C) redispersing the shredded solid mass at an elevated temperature in a vessel in the presence of a dispersant nonpolar liquid having a Kauri-butanol value of less than 30, while maintaining the temperature in the vessel at a temperature sufficient to plasticize and liquify the resin and below that at which the dispersant nonpolar liquid degrades and the resin and/or colorant decomposes, (D) cooling the dispersion, either (1) without stirring to form a gel or solid mass, followed by shredding the gel or solid mass and grinding by means of particulate media with or without the presence of additional liquid; (2) with stirring to form a viscous mixture and grinding by means of particulate media with or without the presence of additional liquid; or (3) while grinding by means of particulate media to prevent the formation of a gel or solid mass with or without the presence of additional liquid; (E) separating the dispersion of toner particles having an average particle size of less than 30 μm from the particulate media, and (F) adding additional nonpolar liquid, polar liquid, or combinations thereof to reduce the concentration of toner particles to between 0.1 to 15 percent by weight with respect to the developer liquid; and (G) adding to the dispersion a liquid soluble ionic or zwitterionic charge director compound.

Claim 60

A process for preparing electrostatic liquid developer comprising (A) dispersing a colorant and a nickel (II) salt in a thermoplastic resin in the absence of a dispersant nonpolar liquid having a Kauri-butanol value of less than 30 to form a solid mass, (B) shredding the solid mass, (C) redispersing the shredded solid mass at an elevated temperature in a vessel in the presence of a dispersant nonpolar liquid having a Kauri-butanol value of less than 30, while maintaining the temperature in the vessel at a temperature sufficient to plasticize and liquify the resin and below that at which the dispersant nonpolar liquid degrades and the resin and/or colorant decomposes, (D) cooling the dispersion, either (1) without stirring to form a gel or solid mass, followed by shredding the gel or solid mass and grinding by means of particulate media with or without the presence of additional liquid; (2) with stirring to form a viscous mixture and grinding by means of particulate media with or without the presence of additional liquid; or (3) while grinding by means of particulate media to prevent the formation of a gel or solid mass with or without the presence of additional liquid; (E) separating the dispersion of toner particles having an average particle size of less than 30 μm from the particulate media, and (F) adding additional nonpolar liquid, polar liquid, or combinations thereof to reduce the concentration of toner particles to between 0.1 to 15 percent by weight with respect to the developer liquid; and (G) adding to the dispersion a liquid soluble ionic or zwitterionic charge director compound.