Process for preparing silver halide dispersions

Claim 2

A process for preparing silver halide dispersion in the absence of a binder as a protective colloid which comprises reacting an aqueous solution of a compound capable of releasing halogen ions with an aqueous solution of a compound capable of releasing silver ions wherein said compound capable of releasing silver salt having a solubility of higher than about 0.2g/100g. H 2 O at 20° C. to form a silver halide product wherein a surface active agent is present in the reaction mixture and wherein an organic solvent sightly soluble in water is added to one of said two solutions before said reaction or to the reaction mixture during said reaction or after said reaction wherein said organic solvent slightly soluble in water has a solubility of 10 parts or less per 100 parts of water at 20° C.

Claim 3

The process of claim 1, wherein said surface active agent is a cationic surface active agent, an anionic surface active agent, an amphoteric surface active agent, and a non-ionic surface active agent.

Claim 4

The process of claim 2, wherein said surface active agent is a cationic surface active agent or a non-ionic surface active agent.

Claim 5

The process of claim 3, wherein said surface active agent is a cationic surface active agent represented by the General Formula (I); ##STR17## wherein R 1 is an alkyl group having 8 to 22 carbon atoms; R 2 , R 3 and R 4 each is an alkyl group having 1 to 10 carbon atoms or an aralkyl group; and X is an anion; or an alkyl pyridinium salt represented by the General Formula (II); ##STR18## wherein R 5 is an alkyl group having from 8 to 22 carbon atoms; and X is as defined with respect to General Formula (I); and wherein the pyridine ring moiety can be substituted with an alkyl group or an aryl group substitutent.

Claim 6

The process of claim 3, wherein said surface active agent is non-ionic surfactant and is an alkyl ether compound having the General Formula (III) r.sub.6 -- o--ch.sub.2 ch.sub.2 o.sub.m H (III) wherein R 6 is an alkyl group having 8 to 22 carbon atoms; and m is an integer of 8 to 50; an alkylaryl ether compound having the General Formula (IV); ##STR19## wherein R 7 is an alkyl group having 4 to 10 carbon atoms; and n is an integer of 8 to 50; an alkyl ester compound represented by the General Formula (V) or the General Formula (VI); r.sub.8 --coo--ch.sub.2 ch.sub.2 o.sub.p H (V) r.sub.8 --coo--ch.sub.2 ch.sub.2 o.sub.p-1 CH.sub.2 CH.sub.2 COOR.sub.8 (VI) wherein R 8 is an alkyl group having 8 to 18 carbon atoms; and p is an integer of 3 to 40; a sorbitan monoalkyl ester compound having the General Formula (VII); ##STR20## wherein R 9 is an alkyl group having 8 to 18 carbon atoms; and q is an integer of 5 to 30; or a polyoxyethylene alkylamine having the General Formula (VIII) ##STR21## wherein R 10 is an alkyl group having 8 to 18 carbon atoms; a and b each is an integer of 0 to 20; and the sum of a and b ranges from 6 to 40.

Claim 7

The process of claim 1, wherein said compound capable of releasing a halogen ion is an inorganic compound represented by the General Formula: MX'.sub.n.sbsb.1 wherein M is a hydrogen atom, an ammonium group or a metal atom; X' is a halogen atom; and n .sbsb.1 is 1 when M is a hydrogen atom or an ammonium group and n .sbsb.1 is the valence of the metal atom when M is metal atom; or an organic halide compound selected from the group consisting of triphenylmethyl chloride, triphenylmethylbromide, monoiodoacetic acid, N-bromosuccinimide, N-bromoacetamide, N-iodoacetamide, iodoform and carbon tetrabromide; wherein said compound capable of releasing a silver ion is a water soluble silver salt having a solubility of higher than about 0.2 g/100 of water at 20° C; wherein either said aqueous solution of said halogen ion-releasing compound or said aqueous solution of said silver ion includes said solvent slightly soluble in water; and wherein the concentration of said surface active agent ranges from about 0.3 to 30% by weight.

Claim 8

The process of claim 1, wherein said surface active agent is present in said solution of said compound capable of releasing a halogen ion.

Claim 9

The process of claim 2, wherein said surface active agent is present in said solution of said compound capable of releasing a halogen ion, in said solution of said compound capable of releasing silver ion, or in both of said solutions.

Claim 10

The process of claim 1, wherein the molar ratio of said silver halide to said surface active agent is from about 1:8 to 1:0.01.

Claim 11

The process of claim 9, therein said molar ratio of said halide to said surface active agent is from 1:4 to 1:0.1.

Claim 12

The process of claim 1, wherein the volume ratio of said water to said solvent is about 1:10 to 10:1.

Claim 13

The process of claim 11, wherein said volume ratio is 1:6 to 6:1.

Claim 14

The process of claim 1, wherein said solvent is liquid at room temperature.

Claim 15

The process of claim 13, wherein said solvent is selected from the group consisting of esters of alcohols having from 1 to 12 carbon atoms and phenols having from 6 to 12 carbon atoms with phosphoric acid, phthalic acid and carboxylic acid, aliphatic hydrocarbons having 5 to 12 carbon atoms and aromatic hydrocarbons.

Claim 16

The process of claim 14, wherein said solvent is tricresyl phosphate, tributyl phosphate, monooctyldibutyl phosphate, dimethyl phthalate, dioctyl phthalate, dimethoxyethyl phthalate, amyl acetate, isoamyl acetate, isobutyl acetate, isopropyl acetate, isobutyl acetate, ethyl acetate, 2-ethylbutyl acetate, butyl acetate, propyl acetate, dioctyl sebacate, dibutyl sebacate, diethyl sebacate, diethyl succinate, propyl formate, butyl formate, amyl formate, ethyl valerate, diethyl tartarate, methyl butyrate, ethyl butyrate, butyl butyrate, isoamyl butyrate, pentane, hexane, heptane, cyclohexane, benzene, toluene or xylene.

Claim 17

The process of claim 1, including the step of subsequently emulsifying said silver halide dispersion.

Claim 18

The process of claim 1, wherein said water soluble silver salt is selected from the group consisting of silver nitrate, silver perchlorate, silver sulfate, silver acetate, a silver ammonium complex salt and a silver amine complex salt.

Claim 19

The process of claim 17, wherein said silver ammonium complex salt has Ag + [(C 2 H 5 ) 3 N] 2 ions or Ag + (H 2 NCH 2 CH 2 NH 2 ) 2 ions.

Claim 20

The process of claim 1, wherein said compound capable of releasing silver ions is silver nitrate.

Claim 21

The process of claim 1, wherein said organic solvent slightly soluble in water has a solubility of 2 parts or less per 100 parts of water at 20° C.

Claim 22

The process of claim 1, wherein said organic solvent slightly soluble in water is added to one of said aqueous solutions prior to said reaction.