US 10,444,618 B2Granted

Method of making silver-containing dispersions

AssigneeEastman Kodak Company

InventorsDeepak Shukla, Kevin M. Donovan, Kevin P. Klubek

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Abstract

A method is used to prepare silver nanoparticles in the form of a silver nanoparticle cellulosic polymeric composite. A cellulosic polymer, organic solvent having a boiling point at atmospheric pressure of 100° C. to 500° C. and a Hansen parameter (δTPolymer) equal to or greater than that of the cellulosic polymer, and a nitrogenous base are mixed to form a premix solution. Upon heating the premix solution to a temperature of at least 75° C., a solution of reducible silver ions is added that is equimolar or less in relation to the nitrogenous base. The weight ratio of reducible silver ions to the cellulosic polymer is 5:1 to 50:1. The resulting silver nanoparticle composite is cooled, isolated, and re-dispersed in an organic solvent, providing a non-aqueous silver-containing dispersion comprising the silver nanoparticle cellulosic polymeric composite.

Claims20

Dependent claims

A method comprising, in sequence:

A) mixing:
(a) one or more polymers selected from one or more of cellulose acetate, cellulose acetate phthalate, cellulose acetate butyrate, cellulose acetate propionate, cellulose acetate trimellitate, hydroxypropylmethyl cellulose phthalate, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropylmethyl cellulose, and carboxymethyl cellulose;
(c) one or more organic solvents, each of which has a boiling point at atmospheric pressure of at least 100° C. and up to but less than 500° C., wherein the Hansen parameter (δTPolymer) of each of the one or more polymers is less than or equal to the Hansen parameter (δTSolvent) of each of the one or more organic solvents;
and
(d) a nitrogenous base having a pKa in acetonitrile of at least 15 and up to and including 25 at 25° C.,
to form a premix solution;
B) heating the premix solution to a temperature of at least 75° C.;
C) while keeping the premix solution at the temperature of at least 75° C., adding a solution of (b) reducible silver ions in (c) the one or more organic solvents to provide an amount of (b) the reducible silver ions in the premix solution that is equimolar or less in relation to the (d) nitrogenous base, and to provide a weight ratio of (b) the reducible silver ions to the one or more (a) polymers of at least 5:1 and up to and including 50:1,
to form a silver nanoparticle composite;
D) after cooling, isolating the silver nanoparticle composite;
and
E) re-dispersing the silver nanoparticle composite in the same or different one or more (c) organic solvents used in A), to provide a non-aqueous silver-containing dispersion comprising the silver nanoparticle composite.

9 more elements

Dependencies are inferred from the claim text.

Facts

Application: 15/713,777Filed 25 Sep 2017
Published: US 2019/0094679 A128 Mar 2019
Granted: 15 Oct 2019
Term ends: Not estimatedThe source records don’t support an estimate.

Classification25 codes

G03C 1/49809
Photothermographic systems, e.g. dry silver: organic silver compounds
C08B 3/16
Preparation of cellulose esters of organic acids: preparation of mixed organic cellulose esters , e.g. cellulose aceto-formate or cellulose…
C08L 1/12
Esters of organic acids , i.e. acylates: cellulose acetate
C08L 1/14
Esters of organic acids , i.e. acylates: mixed esters, e.g. cellulose acetate-butyrate