Liquid electrostatic developer containing multiblock polymers
AssigneeDXImaging
InventorLoretta A. G. Page
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Abstract
Liquid electrostatic developer consisting essentially of A. nonpolar liquid having Kauri-butanol value less than 30, present in major amount, B. thermoplastic resin particles, average by area particle size less than 10 .mu.m, consisting essentially of mixture (1) 80-95% by weight thermoplastic resin and (2) 20 to 5% by weight multiblock copolymer compound as defined, and C. charge director compound. The process of preparation is also defined. The said developer is useful in copying, making proofs, including digital color proofs, lithographic printing plates, and resists.
Claims61
A liquid electrostatic developer consisting essentially of
- A. nonpolar liquid having a Kauri-butanol value of less than 30, present in a major amount,
- B. thermoplastic resin particles having an average by area particle size of less than 10 .mu.m consisting essentially of a mixture of (1) 80 to 95% by weight of a thermoplastic resin and (2) 20 to 5% by weight of a multiblock copolymer compound of the general formula:
- X-Y-(Z)n
- wherein
- X is a polymerized vinyl aromatic
- Y is a polymerized diene, and
- Z is a polymerized vinyl aromatic when n is 1 and a block copolymer of a polymerized vinyl aromatic and a polymerized diene when n is 2 to 10, the weight percentages based on the total weight of resin particles, and
- C. a charge director compound.
Process for preparing liquid electrostatic developer for electrostatic imaging comprising
- (A) dispersing at an elevated temperature in a vessel (1) 80 to 95% by weight of a thermoplastic resin and (2) 20 to 5% by weight of a multiblock copolymer compound of the general formula:
- X-Y-(Z)n
- wherein
- X is a polymerized vinyl aromatic
- Y is a polymerized diene, and
- Z is a polymerized vinyl aromatic when n is 1 and a block copolymer of a polymerized vinyl aromatic and a polymerized diene when n is 2 to 10, the weight percentages based on the total weight of components (1) and (2), and (3) a nonpolar liquid having a Kauri-butanol value of less than 30, while maintaining the temperature in the vessel at a temperature sufficient to plasticize components (1) and (2) and below that at which the nonpolar liquid degrades and components (1) and (2) decompose,
- (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;
- and
- C. separating the dispersion of toner particles having an average by area particle size of less than 10 .mu.m from the particulate media, and
- D. adding to the dispersion during or subsequent to Step A a nonpolar liquid soluble charge director compound.
A process for preparing electrostatic liquid developer for electrostatic imaging comprising
- (A) mixing in a vessel (1) a thermoplastic resin and (2) multiblock copolymer of the general formula:
- X-Y-(Z)n
- wherein
- X is a polymerized vinyl aromatic
- Y is a polymerized diene, and
- Z is a polymerized vinyl aromatic when n is 1 and a block copolymer of a polymerized vinyl aromatic and a polymerized diene when n is 2 to 10, 80 to 95% by weight (1) and 20 to 5% by weight (2), respectively, based on the total weight of components (1) and (2);
- (3) a colorant and/or (4) adjuvant in the absence of a liquid 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 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, to form a dispersion of toner particles in the liquid,
- (D) separating the particulate media from the dispersion of toner particles having an average by area particle size of less than 10 .mu.m,
- (E) adding to the dispersion during or subsequent to step (C) a charge director compound.
Dependencies are inferred from the claim text.