Oil-containing microcapsules and method for their production

Claim 2

total amount of hydrophilic colloids present. 3. The method of claim .[.1.]. .Iadd.32 .Iaddend.wherein said modified cellulose is selected from the group consisting of carboxymethyl cellulose, carboxyethyl cellulose,

Claim 3

cellulose sulfate, cellulose phosphate and a metal salt thereof. 4. The method of claim .[.1.]. .Iadd.32 .Iaddend.wherein in said anionic starch derivative is selected from the group consisting of carboxymethyl starch, carboxyethyl starch, starch sulfate, starch phosphate and starch xanthate.

Claim 4

. The method of claim .[.1.]. .Iadd.32 .Iaddend.wherein said

Claim 5

polyelectrolyte is an anionic acid polysaccharide. 6. The method of claim .[.1.]. .Iadd.32 .Iaddend.wherein said polyelectrolyte is a hydroxyethyl

Claim 6

cellulose derivative. 7. The method of claim .[.1.]. .Iadd.32 .Iaddend.wherein said polyelectrolyte is a vinylbenzene sulfonate

Claim 7

copolymer. 8. The method of claim .[.1.]. .Iadd.32 .Iaddend.wherein said

Claim 8

polyelectrolyte is an acrylic acid copolymer. 9. The method of claim .[.1.]. .Iadd.32 .Iaddend.wherein said microcapsules contain a colorless

Claim 9

leuco dye capable of forming a color dye when contacted with clay. 10. Oil-containing microcapsules produced according to the method of claim

Claim 10

.[.1.]. .Iadd.32. .Iaddend. 11. Oil-containing microcapsules produced

Claim 11

according to the method of claim 9. 12. The method of claim .[.1.]. .Iadd.32.Iaddend., wherein said condensate of naphthalene sulfonic acid

Claim 12

and Formalin has a degree of polymerization ranging from 5 to 9. 13. The method of claim .[.1.]. .Iadd.32.Iaddend., wherein said vinyl-benzene sulfonate in said vinyl-benzene sulfonate copolymer is present in an

Claim 13

amount of from 45 to 95 mol percent. 14. The method of claim .[.1.]. .Iadd.32.Iaddend., wherein said vinyl-benzene sulfonate in said vinyl-benzene sulfonate copolymer is present in an amount of from 60 to 85

Claim 14

mol percent. 15. The method of claim .[.1.]. .Iadd.32.Iaddend., wherein the molecular weight of said vinyl-benzene sulfonate copolymer ranges from

Claim 15

10,000 to 3,000,000. 16. The method of claim .[.1.]. .Iadd.32.Iaddend., wherein the molecular weight of said vinyl-benzene sulfonate copolymer

Claim 16

ranges from 100,000 to 1,000,000. 17. The method of claim .[.1.]. .Iadd.32.Iaddend., wherein said acrylic acid in said acrylic acid

Claim 17

copolymer is present in an amount of from 40 to 95 mol percent. 18. The method of claim .[.1.]. .Iadd.32.Iaddend., wherein said acrylic acid in said acrylic acid copolymer is present in an amount of from 50 to 85 mol

Claim 18

percent. 19. The method of claim .[.1.]. .Iadd.32.Iaddend., wherein said acrylic acid copolymer has a molecular weight of from 6,000 to 2,000,000.

Claim 20

to 1,000,000. 21. The method of claim .[.1.]. .Iadd.32.Iaddend., wherein said hydrophilic colloid is a member selected from the .[.roup.]. .Iadd.group .Iaddend.consisting of gelatin, casein, alginate, gum arabic, styrene-maleic anhydride copolymers, and polyethylene-maleic anhydride

Claim 21

copolymers. 22. The method of claim .[.1.]. .Iadd.32.Iaddend., wherein the addition of said polyelectrolyte takes place at a temperature of below

Claim 22

20° C. 23. The method of claim .[.1.]. .Iadd.32.Iaddend., wherein the addition of said polyelectrolyte takes place at a temperature of below

Claim 23

15° C. 24. The method of claim .[.1.]. .Iadd.32.Iaddend., wherein

Claim 24

said pH is 7.0. 25. The method of claim .[.1.]. .Iadd.32.Iaddend., wherein

Claim 25

said pH is 7.5. 26. The method of claim .[.1.]. .Iadd.32.Iaddend., wherein

Claim 26

said pH is 8.0. 27. The method of claim .[.1.]. .Iadd.32.Iaddend., wherein

Claim 27

said pH is 10.0. 28. The method of claim 4, wherein the cellulose of said anionic starch derivative has a degree of polymerization ranging from 50

Claim 28

to 500. 29. The method of claim 4, wherein the cellulose of said anionic starch derivative has a degree of esterification or etherification of from

Claim 29

5 to 1.2. 30. The method of claim .[.1.]. .Iadd.32.Iaddend., wherein the

Claim 30

adjustment of pH occurs before addition of the hardening agent. 31. The method of claim .[.1.]. .Iadd.32.Iaddend., wherein the adjustment of pH occurs after the addition of the hardening agent. .Iadd. 32. In a method for producing oil-containing microcapsules by: (a) emulsifying a water-immiscible oil and an aqueous solution containing gelatin and another hydrophilic colloid, or (b) emulsifying a water-immiscible oil and an aqueous solution of a hydrophilic colloid to obtain a first sol, ionizable in water and admixing said first sol and an aqueous solution of a hydrophilic colloid to obtain a second sol, ionizable in water and having an electric charge opposite to that of said first sol, one of said colloids being gelatin, (c) adding water to either emulsion derived from (a) or (b) and/or adjusting the pH thereof to cause coacervation, thus to obtain coacervates, wherein the complex colloids are deposited around the individual oil drops, (d) cooling the coacervates to cause gelation thereof, and converting the pH to alkalinity, and (e) adding a hardening agent to the system and adjusting the pH thereof to a range of from 7 to 11, the improvement which comprises: adding an aqueous solution of a polyelectrolyte having anionic functional groups to the dispersion containing said coacervates at a temperature lower than the gelling point of the gelatin, in an amount sufficient to prevent a rise in viscosity thereof, said addition being made after gelation of the coacervates has occurred and before the adjustment of said pH to a range of from 7 to 11 and the adding of said hardening agent to the system has occurred, and said adjusting of said pH occurring before, after, or simultaneously with the addition of said hardening agent, said polyelectrolyte being a member selected from the group consisting of a modified cellulose comprising polysaccharides having beta-1,4-glucoside bonds of glucoses and having anionic functional groups, an anionic starch derivative composed of a linear polysaccharide amylose formed by only alpha-1,4 bonds of D-glucose, and a branched polysaccharide amylopectin formed by mainly alpha-1,4 bonds of D-glucose and a partially side chain branched by alpha-1,6 bonds, an anionic acid polysaccharide, obtained by polycondensing linearly D-galacturonic acid between the alpha-1,4 bonds thereof, said acid polysaccharide containing pectin, pectic acid, and pectinic acid, a condensate of naphthalene sulfonic acid and formalin, which condensate is represented by the formula: ##SPC5## wherein X is a hydrogen atom, an alkali metal, or an ammonium group, and n is a positive integer, a hydroxyethyl cellulose derivative selected from the group consisting of the carboxymethyl ether of hydroxyethyl cellulose, hydroxyethyl cellulose sulfate, and hydroxyethyl cellulose phosphate, a vinyl-benzene sulfonate copolymer selected from the group consisting of a vinylbenzene sulfonate-acryloylmorpholine copolymer, a vinylbenzene sulfonate-morpholino-methylacrylamide copolymer, a vinylbenzene sulfonate acrylamide copolymer, a vinylbenzene sulfonate-vinylpyrrolidone copolymer, and a vinylbenzene sulfonate-methyloxymethylacrylamide; said copolymer having the following group within its molecular structure: ##SPC6## wherein M is an alkali metal and n is a positive integer, and an acrylic acid copolymer selected from the group consisting of an acrylic acid acryloylmorpholine copolymer, an acrylic acid-morpholinomethylacrylamide copolymer, an acrylic acid-acrylamide copolymer, an acrylic acid-vinylpyrrolidone copolymer, and an acrylic acid-methoxymethylacrylamide copolymer, said copolymer having the following group within its molecular structure: ##EQU3## wherein X is a hydrogen atom or an alkali metal and n is a positive integer. .Iaddend.