Method of combining optical brighteners with polymers for stability in bleach and encapsulated product

Claim 2

Method according to claim 1 including maintaining a reaction temperature above about 130* F in the polymerization mixture during steps (d) and (f).

Claim 3

Method according to claim 3 including also cooling the reaction mixture to less than 130* F between step (d) and step (f).

Claim 4

Method according to claim 1 including forming particles in step (f) having an average particle size between 0.1 and 2 microns.

Claim 5

Method according to claim 1 including also adding from 0.5 to 25 parts of a hydrophylic monomer selected from acrylic monomers selected from the hydroxyester, ether, amide and cyano derivatives of methacrylic and acrylic acid and vinyl sulfonate monomers having the formula R-CH=CH-SO3Me in which R is hydrogen or a hydrocarbon radical free of aliphatic unsaturation having up to 10 carbon atoms and Me is an alkali metal, in place of an equal weight amount of the styrene monomer.

Claim 6

Method according to claim 1 in which said optical brightener compound is selected from 4,4''-diaminostilbene-2,2''-disulfonic acids, dibenzothiophene-5,5-dioxides, azoles, coumarin, pyrazine, and 4-aminonaphthalimides.

Claim 7

Method of combining an optical brightener compound with synthetic organic polymer consisting essentially per 100 parts by weight of 88 to 92 parts of styrene and eight to 12 parts of an acrylic or methacrylic acid to retain optical brightening properties in aqueous bleach solutions, which includes the steps of: a. dissolving at least 10% by weight based on the total amount of styrene in the polymer of an optical brightener compound selected from 4,4''-diaminostilbene-2,2''-disulfonic acid derived, dibenzothiophene-5,5-dioxide derived, and azole derived optical brightener compounds in from 60 to 80 percent by weight of the total styrene monomer; b. dissolving from 50 to 100% by weight of the total acrylic or methacrylic monomer in water; c. combining the optical brightener containing styrene from step (a) and the aqueous vinyl acid solution of steps (b) with surfactant to form an emulsion polymerization mixture; d-1. heating the mixture of step (c) to an elevated temperature less than 130* F in the presence of a polymerization reaction catalyst and reacting the monomers at the temperatures of the exotherm; d-2. cooling the polymerization reaction mixture to less than 130* F; e. adding the balance of the styrene and acrylic acid or methacrylic acid monomer and maintaining at less than 130* F for at least 15 minutes following addition; f. adding additional polymerization catalyst to the reaction mixture heating the mixture with the ensuing exotherm to a temperature above 130* F to polymerize the added styrene monomer onto the polymer of step (d-1) to form a particulate polymer having an average particle size between 0.1 and 2 microns which protectively incorporates said brightener compound.

Claim 8

Method according to claim 8 including also substituting for a like weight amount of styrene in step (a) from 60 to 80 percent by weight of from five to 10 parts per 100 parts of polymer of an acrylic monomer selected from the hydroxyester, ether, amide and cyano derivatives of acrylic or methacrylic acid or a vinyl sulfonate monomer having the formula R-CH=CH-SO3Me in which R is hydrogen or an aromatic or alkyl radical having up to 10 carbon atoms and Me is an alkali metal and incorporating the balance of said acrylic or sulfonate monomer into the reaction mixture in step (e).

Claim 9

Method according to claim 9 in which said polymer contains from 0.5 to 5 percent by weight of said optical brightening compound, based on the weight of styrene in the polymer.

Claim 10

ParTicles for protectively carrying oxidizer sensitive optical brightening compounds in aqueous bleach said particles comprising an inner portion consisting essentially of an oxidizer sensitive compound and a styrene-acrylic polymer and an outer portion forming an encapsulating layer over the inner portion and consisting essentially of styrene polymer free of said compound, said particles comprising per 100 parts of polymer from 65 to 98 parts of a styrene monomer selected from the group consisting of styrene, bromostyrene, chlorostyrene and alkyl substituted styrenes having up to 12 carbon atoms and conversely from 2 to 35 parts of methacrylic or acrylic acid monomer copolymerized therewith, said inner portion polymer containing a major proportion but less than 90 percent by weight of said styrene and at least a major weight proportion of said acid monomers, said outer portion polymer containing the balance of said monomers.

Claim 11

Particles according to claim 11 in which said particles contain from 0.5 to 5 percent by weight of said compound based on the weight of the styrene in said polymer.

Claim 12

Particles according to claim 11 in which said optical brightener compound is selected from the group consisting of 4, 4'' diaminostilbene-2,2''-disulfonic acid, dibenzothiophene-5,5-dioxides azoles, coumarin, pyrazine, and 4-aminonaphthalimide.

Claim 13

Particles according to claim 11 in which said particles have an average particle size between 0.5 and 2 microns.

Claim 14

Particles according to claim 11 in which said particles comprise per 100 parts from 88 to 92 parts of styrene monomer and from eight to 12 parts of methacrylic or acrylic acid.

Claim 15

Particles according to claim 15 in which said inner portion contains from 60 to 80 weight percent of said styrene and from 50 to 100 weight percent of said acid.

Claim 16

Particles according to claim 16 including also from five to 10 parts by weight per 100 parts of polymer in replacement of a like amount of styrene of a hydrophilic monomer selected from the hydroxy-ester, ether, amide and cyano derivatives of acrylic or methacrylic acid or a vinyl sulfonate monomer having the formula R-CH=CH-SO3Me in which R is hydrogen or an aromatic or alkyl radical having up to 10 carbon atoms and Me is an alkali metal.

Claim 17

Particles according to claim 11 including also from five to 10 parts by weight per 100 parts of polymer in replacement of a like amount of styrene of a hydrophilic monomer selected from the hydroxy-ester, ether, amide and cyano derivatives of acrylic or methacrylic acid or a vinyl sulfonate monomer having the formula R-CH=CH-SO3Me in which R is hydrogen or an aromatic or alkyl radical having up to 10 carbon atoms and Me is an alkali metal.

Claim 18

Particles for protectively carrying an optical brightener compound selected from the group consisting of 4,4''-diaminostilbine-2,2''-disulfonic acids, dibenzothiophene-5,5-dioxides and azoles in aqueous bleach comprising particles of an average particle size between 0.5 and 2 microns and having a center portion consisting essentially of said brightener compound in an amount between 0.5 and 5 percent by weight based on the styrene weight in the particles and a styrene-acrylic copolymer and an outer encapsulating layer formed over the center portion and consisting essentially of styrene polymer free of said compound, said particles consisting essentially of from 65 to 98 parts of styrene and from two to 35 parts of methacrylic or acrylic acid copolymerized therewith said center portion containing from 60 to 80 weight percent of the styrene present in said particles and from 50 to 100 percent of the acid present in said particles, said outer portion containing the balance of the styrEne and acid present in the particles.

Claim 19

Particles according to claim 19 including also in replacement of a like weight amount of styrene in said particles from 5 to 10 parts by weight of a hydrophilic comonomer selected from the hydroxyester, ether, amide and cyano derivatives of acrylic or methacrylic acid or a vinyl sulfonate monomer having the formula R-CH=CH-SO3Me in which R is hydrogen or an aromatic or alkyl radical having up to 10 carbon atoms and Me is sodium or potassium, said center portion containing from 60 to 80 percent of said hydrophilic comonomer and said outer portion the balance thereof.