NON-AQUEOUS SILVER-CONTAINING DISPERSIONS
A non-aqueous silver-containing dispersion is prepared containing a silver nanoparticle composite comprising silver and a cellulosic polymers so that the silver nanoparticle composite is present at a weight ratio to a cellulosic polymers of at least 5:1 and up to and including 50:1. This dispersion also contains an organic solvent that has a boiling point, at atmospheric pressure, of 100° C. to 500° C. The Hansen parameter (δ T Polymer ) of the cellulosic polymer is less than or equal to the Hansen parameter (δ T Solvent ) of the organic solvent. A nitrogenous base having a pKa in acetonitrile of 15 to 25 at 25° C. is also present in an equimolar amount or molar excess in relation to the amount of silver.
1 . A non-aqueous silver-containing dispersion, comprising:
a silver nanoparticle composite comprising silver and one or more (a) 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, wherein silver is present in the silver nanoparticle composite at a weight ratio to the one or more (a) polymers of at least 5:1 and up to and including 50:1;
(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 (δ T Polymer ) of each of the one or more polymers is less than or equal to the Hansen parameter (δ T Solvent ) 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., the nitrogenous base being present in an equimolar amount or molar excess in relation to the amount of silver.
2 . The non-aqueous silver-containing dispersion of claim 1 , wherein the silver is present at a weight ratio to the one or more (a) polymers of at least 5:1 and up to and including 20:1.
3 . The non-aqueous silver-containing dispersion of claim 1 , wherein the one or more (c) organic solvents is one or more hydroxylic organic solvents each having an α-hydrogen atom and is chosen from the group consisting of ethanol, n-propanol, n-butanol, n-pentanol, n-hexanol, n-octanol, 2-ethyl-1-hexanol, n-decanol, ethylene glycol, propylene glycol, benzyl alcohol, isobutyl alcohol, isoamyl alcohol, secondary butylcarbinol, isopropyl alcohol, secondary butyl alcohol, secondary amyl alcohol, diethyl carbinol, methyl isobutyl carbinol, methyl-3-heptanol, diisobutyl carbinol, dodecanol-Z, methyl allyl carbinol, cyclohexanol, methyl cyclohexyl carbinol, phenyl methyl carbinol, 2-methoxyethanol, 2-ethoxyethanol, diethylene glycol monoethyl ether, methoxy isopropanol, and a combination thereof.
4 . The non-aqueous silver-containing dispersion of claim 1 , wherein the nitrogenous base is an aromatic cyclic compound.
5 . The non-aqueous silver-containing dispersion of claim 1 , wherein the nitrogenous base is selected from the group consisting of 1,4-diazabicyclo[2.2.2]octane (DABCO), cyclohexylamine, piperidine, N-methyl pipperidine, N-methyl-3-piperidinol, ethanol amine, 2-(ethylamino)ethanol, 2-(methylamino)ethanol, 2-(butylamino)ethanol, methyldiethanolamine (MDEA), diethanolamine (DEA), diglycolamine (DGA), diethylaminoethanol (DEAE), substituted or unsubstituted non-polymeric pyridine, picolines, lutidines, quinoline, purine, isoquinoline, imidazole, benzimidazole, benzthiazole, thiazole, oxazole, benzoxazole, 4,4′-bipyridine, pyrazine, triazine, pyrimidine, nicotinic acid, and isonicotinic acid compounds, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), and a combination thereof.
6 . The non-aqueous silver-containing dispersion of claim 1 , wherein the (a) one or more polymers is one or more of carboxymethyl cellulose, cellulose acetate butyrate, ethyl cellulose, cellulose acetate, and cellulose acetate propionate.
7 . The non-aqueous silver-containing dispersion of claim 1 , further containing (e) a carbon black.
8 . The non-aqueous silver-containing dispersion of claim 1 , having a viscosity of at least 1 centipoise (0.001 Pascal sec) and up to and including 5000 centipoise (5 Pascal sec) at 25° C.
9 . The non-aqueous silver-containing dispersion of claim 1 , having a viscosity of at least 3 centipoise (0.003 Pascal sec) and up to and including 10 centipoise (0.01 Pascal sec) at 25° C.
10 . The non-aqueous silver-containing dispersion of claim 1 , wherein the silver nanoparticle composite has a mean particle size (d50) of at least 10 nm and up to and including 1500 nm.
11 . The non-aqueous silver-containing dispersion of claim 1 , wherein the silver nanoparticle composite has a mean particle size (d50) of at least 20 nm and up to and including 500 nm.