RU2021105968A - OPTICALLY CLARIFIED LATEXES - Google Patents

Claims (55)

1. A process for preparing an aqueous composition, preferably an aqueous latex binder, by emulsion polymerization of at least one ethylenically unsaturated monomer in the presence of at least one water-soluble diaminostilbene-disulfone optical brightener of formula (1)

(one), in which R ¹ and R ⁶ are independently hydrogen, linear or branched C ₁ -C ₄ alkyl, linear or branched C ₁ -C ₄ hydroxyalkyl, CH ₂ CH ₂ CONH ₂ or CH ₂ CH ₂ CN, R ² and R ⁴ are independently hydrogen, linear or branched C ₁ -C ₄ alkyl, linear or branched C ₁ -C ₄ hydroxyalkyl, CH ₂ CO ₂ M, CH ₂ CH ₂ CONH ₂ or CH ₂ CH ₂ CN , R ³ and R ⁵ are independently linear or branched C ₁ -C ₄ alkyl, linear or branched C ₁ -C ₄ hydroxyalkyl, CH ₂ CO ₂ M, CH(CO ₂ M)CH ₂ CO ₂ M, CH( CO ₂ M)CH ₂ CH ₂ CO ₂ M, benzyl or R ² and R ³ together with their neighboring nitrogen atom represent a morpholine ring and/or R ⁴ and R ⁵ together with their neighboring nitrogen atom represent a morpholine ring, R ⁷ and R ⁸ are independently hydrogen, linear or branched C ₁ -C ₄ alkyl X and Y are independently CO ₂ M or SO ₃ M, n and m are independently an integer selected from 0, 1, or 2, and M is at least one cation for balancing the anionic charge of the optical brightener and is selected from the group consisting of or essentially consisting of hydrogen, an alkali metal cation, an alkaline earth metal cation, ammonium, an ammonium which is mono-, di-, tri-, or tetra-substituted linear or branched C ₁ -C ₄ alkyl radical, ammonium, which is a mono-, di -, tri - or tetrasubstituted linear or branched C ₁ -C ₄ hydroxyalkyl radical, ammonium, which is a di-, tri - or tetrasubstituted mixture of linear or branched C ₁ -C ₄ alkyl radicals, or linear or branched C ₁ -C ₄ hydroxyalkyl radicals, or a mixture of these cations. 2. The method according to p. 1, in which at least one water-soluble diaminostilbene-disulfone optical brightener of formula (1) R ¹ and R ⁶ are independently hydrogen, methyl, linear or branched C ₁ -C ₄ hydroxyalkyl or CH ₂ CH ₂ CONH ₂ , R ² and R ⁴ are independently hydrogen, linear or branched C ₁ -C ₄ alkyl, linear or branched C ₁ -C ₄ hydroxyalkyl, CH ₂ CH ₂ CONH ₂ or CH ₂ CH ₂ CN, R ³ and R ⁵ are independently linear or branched C ₁ -C ₄ alkyl, linear or branched C ₁ -C ₄ hydroxyalkyl, CH(CO ₂ M)CH ₂ CO ₂ M, CH(CO ₂ M)CH ₂ CH ₂ CO ₂ M, benzyl or R ² and R ³ together with their neighboring nitrogen atom represent a morpholine ring and/or R ⁴ and R ⁵ together with their neighboring nitrogen atom represent a morpholine ring, and R ⁷ and R ⁸ are independently hydrogen or methyl, and M means at least one cation, as defined in paragraph 1 of the claims. 3. The method according to at least one of paragraphs. 1 or 2, in which at least one water-soluble diaminostilbene-disulfone optical brightener of formula (1) R ¹ and R ⁶ are hydrogen, R ² and R ⁴ are independently hydrogen, linear or branched C ₁ -C ₂ alkyl, linear or branched C ₁ -C ₃ hydroxyalkyl, R ³ and R ⁵ are independently linear or branched C ₁ -C ₂ alkyl, linear or branched C ₁ -C ₃ hydroxyalkyl, CH(CO ₂ M)CH ₂ CO ₂ M, CH(CO ₂ M)CH ₂ CH ₂ CO ₂ M, or R ² and R ³ together with their neighboring nitrogen atom represent a morpholine ring and/or R ⁴ and R ⁵ together with their neighboring nitrogen atom represent a morpholine ring, and R ⁷ and R ⁸ are independently hydrogen or methyl, and M means at least one cation, as defined in paragraph 1 of the claims. 4. The method according to at least one of paragraphs. 1-3, in which at least one ethylenically unsaturated monomer is selected from (a) C ₁ -C ₁₈ -alkyl esters of (meth)acrylic acid, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl versatates, styrene and α-methylstyrene; (b) hydrophilic monomers such as (meth)acrylic acid, itaconic acid, vinylsulfonic acid, C ₁ -C ₈ -hydroxyalkyl esters of C ₁ -C ₆ -carboxylic acids, (meth) acrylamide, N-methylol (meth) acrylamide, ( meth)acrylonitrile, N-vinylformamide and N-vinylpyrrolidone; or (c) crosslinkers that have two or more ethylenically unsaturated double bonds, such as ethylene glycol di(meth)acrylate, butanediol di(meth)acrylate, hexanediol di(meth)acrylate, divinylbenzene and trivinylbenzene; or mixtures of two or more of them. 5. The method according to at least one of paragraphs. 1-4, in which at least one ethylenically unsaturated monomer is selected from (a) C ₁ -C ₆ -alkyl esters of (meth)acrylic acid, vinyl acetate, vinyl propionate and styrene; (b) hydrophilic monomers such as (meth)acrylic acid, vinylsulfonic acid, (meth)acrylamide and (meth)acrylonitrile; or mixtures of two or more of them. 6. The method according to at least one of paragraphs. 1-5, wherein at least one ethylenically unsaturated monomer is selected from (a) methyl methacrylate, butyl acrylate, vinyl acetate, and styrene; (b) hydrophilic monomers such as (meth)acrylic acid, vinylsulfonic acid and acrylamide; or mixtures of two or more of them. 7. The method according to at least one of paragraphs. 1-6, in which the emulsion polymerization is initiated with a water-soluble azo compound of formula (2) and/or formula (3)

in which X and Y are independently O or NH, R and R' are independently hydrogen or linear or branched C ₁ -C ₄ alkyl substituted with one or more hydroxyl, CO ₃ M ¹ or CO ₃ M ² groups, where M ¹ and M ² represent at least one cation to balance the anionic charge of the azo compound of formula (3) and are independently selected from the group consisting of or essentially consisting of hydrogen, an alkali metal cation, an alkaline earth metal cation, ammonium, an ammonium which is mono-, di-, tri-, or tetra-substituted linear or branched C ₁ -C ₄ alkyl radical, ammonium, which is a mono-, di -, tri - or tetrasubstituted linear or branched C ₁ -C ₄ hydroxyalkyl radical, ammonium, which is a di-, tri - or tetrasubstituted mixture of linear or branched C ₁ -C ₄ alkyl radicals, or linear or branched C ₁ -C ₄ hydroxyalkyl radicals, or a mixture of these cations. 8. The method according to at least one of the previous paragraphs. 1-7, wherein the emulsion polymerization comprises at least the following four steps (a) to (d): a) preparing an aqueous solution containing or consisting of at least one water-soluble diaminostilbene-disulfone optical brightener of formula (1) and optionally at least one dispersing agent, and b) preparing a homogeneous pre-dispersion, wherein the pre-dispersion contains or consists of at least one ethylenically unsaturated monomer, water and at least one dispersing agent, and c) preparing an aqueous solution containing or consisting of a water-soluble azo compound of formula (2) and/or formula (3), and d) adding the pre-dispersion obtained in step (b) and the aqueous solution obtained in step (c) simultaneously to the aqueous solution obtained in step (a). 9. An aqueous composition obtainable by a process for preparing an aqueous composition, preferably an aqueous latex binder, by emulsion polymerization of at least one ethylenically unsaturated monomer in the presence of at least one water-soluble diaminostilbene-disulfone optical brightener of formula (1)

, in which R ¹ and R ⁶ are independently hydrogen, linear or branched C ₁ -C ₄ alkyl, linear or branched C ₁ -C ₄ hydroxyalkyl, CH ₂ CH ₂ CONH ₂ or CH ₂ CH ₂ CN, R ² and R ⁴ are independently hydrogen, linear or branched C ₁ -C ₄ alkyl, linear or branched C ₁ -C ₄ hydroxyalkyl, CH ₂ CO ₂ M, CH ₂ CH ₂ CONH ₂ or CH ₂ CH ₂ CN , R ³ and R ⁵ are independently linear or branched C ₁ -C ₄ alkyl, linear or branched C ₁ -C ₄ hydroxyalkyl, CH ₂ CO ₂ M, CH(CO ₂ M)CH ₂ CO ₂ M, CH( CO ₂ M)CH ₂ CH ₂ CO ₂ M, benzyl or R ² and R ³ together with their neighboring nitrogen atom represent a morpholine ring and/or R ⁴ and R ⁵ together with their neighboring nitrogen atom represent a morpholine ring, R ⁷ and R ⁸ are independently hydrogen, linear or branched C ₁ -C ₄ alkyl X and Y are independently CO ₂ M or SO ₃ M, n and m are independently an integer selected from 0, 1, or 2, and M is at least one cation for balancing the anionic charge of the optical brightener and is selected from the group consisting of or essentially consisting of hydrogen, an alkali metal cation, an alkaline earth metal cation, ammonium, an ammonium which is mono-, di-, tri-, or tetra-substituted linear or branched C ₁ -C ₄ alkyl radical, ammonium, which is a mono-, di -, tri - or tetrasubstituted linear or branched C ₁ -C ₄ hydroxyalkyl radical, ammonium, which is a di-, tri - or tetrasubstituted mixture of linear or branched C ₁ -C ₄ alkyl radicals, or linear or branched C ₁ -C ₄ hydroxyalkyl radicals, or a mixture of these cations. 10. An aqueous composition according to claim 9, wherein at least one other additive is present, wherein the additive is selected from one or more biocides, one or more antifoam agents, one or more preservatives, one or more antifreeze additives, one or more thickeners, or mixtures thereof. 11. Aqueous composition according to at least one of paragraphs. 9 or 10, in which more than 90% by weight, or more than 92% by weight, or more than 94% by weight, or more than 96% by weight, or more than 98% by weight, or more than 99% by weight of an optical brightener of the formula ( 1) were retained in the polymer, the weight % being based on the total amount of formula (1) optical brightener present in the aqueous composition. 12. The use of an aqueous composition according to at least one of paragraphs. 9-11 for optically brightening a cellulose substrate, preferably wherein an aqueous composition is used in the coating composition. 13. Coating composition containing at least an aqueous composition in accordance with at least one of paragraphs. 9-11. 14. A method for optically brightening a cellulose substrate, comprising steps i) applying an aqueous composition according to at least one of paragraphs. 9-11 or the coating composition of claim 13 on a cellulose substrate; and ii) drying the cellulose substrate. 12. Cellulose substrate treated with an aqueous composition as stated in at least one of paragraphs. 9-11 or the coating composition according to claim 13.