Composite particles for toner additives
AssigneeCabot Corporation
InventorsHairuo Tu, Jincheng Xiong, Paul S. Palumbo, Dmitry Fomitchev
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Abstract
Metal oxide-polymer composite particles have a median particle size D50 of 40-75 nm or 100-150 nm and an average RTA of at least 0.06. Alternatively or in addition, metal oxide-polymer composites comprise two or more populations of metal oxide particles differing in size, particle size distribution, or shape. Alternatively or in addition, the use of a multicomponent hydrophobizing system including an alkylsilane to fabricate metal oxide-polymer composite particles increases the tribocharge of the composite particles.
Claims25
Metal oxide-polymer composite particles in powder form comprising a plurality of metal oxide particles and a polymer matrix, wherein:
- the metal oxide particles are surface-modified with a first hydrophobizing system comprising a bifunctional component via which the metal oxide particles are covalently attached to the polymer matrix;
- the polymer of the polymer matrix is a polymer or co-polymer of the bifunctional component;
- and
- the metal oxide-polymer composite particles have either a) a median particle size D50 of 40-75 nm and an average RTA of at least 0.06, or b) a median particle size D50 of 100-150 nm and an average RTA of at least 0.06.
(canceled)
(canceled)
A toner composition comprising toner particles mixed with a powder comprising metal oxide-polymer composite particles comprising a plurality of metal oxide particles and a polymer matrix, wherein:
- the metal oxide particles are surface-modified with a first hydrophobizing system comprising a bifunctional component via which the metal oxide particles are covalently attached to the polymer matrix and a monofunctional component that is covalently attached to the metal oxide particles;
- at least a portion of the surface of the metal oxide-polymer composite particles is modified with a second hydrophobizing agent, wherein the polymer of the polymer matrix is a polymer or co-polymer of the bifunctional component;
- and,
- a tribocharge of the toner at HH conditions is at least at least 9% greater in magnitude than that of a toner comprising a control metal oxide-polymer composite in which the monofunctional component is replaced with the bifunctional component.
A method of making a composite particle, comprising:
- preparing an aqueous dispersion comprising metal oxide particles and a first hydrophobizing system comprising a bifunctional component and a monofunctional component, wherein the bifunctional component and the monofunctional component become chemically attached to the metal oxide particles;
- adding a polymerization initiator to the aqueous dispersion to form metal oxide-polymer composite particles having metal oxide particles at their surfaces, wherein a polymer matrix of the metal oxide-polymer composite particles is a polymer or copolymer of the first hydrophobizing system;
- and
- drying the metal oxide-polymer composite particles to form a powder.
25-48. (canceled)
Dependencies are inferred from the claim text.