Claims:We Claim:

1. A dye-adsorbing polymer nanosphere composition comprising crosslinked polar nanosphere-A, derived from monomers of Structures I, II and III, and monomer selected from a group consisting of crosslink monomer-IV, graft monomer-V, monomer-VI and a combination thereof;

Structure I Structure II Structure III
Wherein R1 = H, aliphatic group of 1 to 2 carbon atoms or aromatic group;
R2 = Aliphatic group of 1 to 18 carbon atoms, HOCH2CH2- or HOCH2CH2CH2- and R3 = H or aliphatic group of 1 to 3 carbon atoms and
R4 = H or Me;
wherein the crosslink monomer-IV is selected from a group consisting of trimethylol propane trimethacrylate, trimethylolpropane (EO)n triacrylate, where n=3-15, glycerinetriacrylate, glycerine (EO)3 triacrylate, pentaerythritol triacrylate, tris(2-hydroxyethyl)isocyanurate triacrylate, pentaerythritol(EO)n tetraacrylate, ditrimethylolpropanetriacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dierythritolhexaacrylate and a combination thereof;

wherein, the graft monomer-V is selected from a group consisting of phenoxybenzylacrylate (M1122), biphenylmethylacrylate (M1192), o-phenylphenoethoxyacrylate (M1142), benzyl methacrylate, caprolactone acrylate, phenol(EO)n acrylate, where n ranges from 1 to 4, nonylphenol (EO)n acrylate, where n is either 4 or 8, ethoxyethyl acrylate, poly(EO) methoxy monoether methacrylate, where number of EO units in the poly(EO) ranges from 200 to 2000, polypropyleneglycol monomethacrylate and a combination thereof;

wherein, the monomer-VI is selected from a group consisting of acrylic acid, methacrylic acid, sodium salt of vinylsulphonic acid, sodium salt of vinylbenzene sulphonic acid or sodium salt of vinylbenzoic acid, sodium salt of 2-acrylamido-2-methyl-1-propane sulphonic acid, N,N-dimethyl acrylamide, diacetone acrylamide, N-hydroxymethyl acrylamide and a combination thereof;

Wherein, the crosslinked polar nanosphere-A is in the form of a colorless aqueous dispersion having solid content ranging from 1 to 25 weight%; and

wherein, the amount of monomer with the Structure III, is not more than about 32 weight% of the total weight of the monomer composition of crosslinked polar nanosphere-A.

2. The dye-adsorbing polymer nanosphere composition of claim 1, wherein the amounts of monomers of structural units derived from the Structure I, the Structure II, the Structure III, the monomer-IV, the monomer-V and the monomer-VI present in the polymer nanosphere composition range from about 18 to about 29 weight%, about 18 to about 32 weight%, about 16 to about 32 weight%, about 6 to about 25 weight%, about 0 to about 15 weight% and about 2 to about 12 weight% respectively based on the total weight of the monomer composition of crosslinked polar nanosphere-A.
3. The dye-adsorbing polymer nanosphere composition of claim 1, wherein the amounts of monomers of structural units derived from the structure I, the structure II, the structure III, the monomer-IV and the monomer-V present in the polymer nanosphere composition ranges from about 19 to about 26 weight %, about 20 to about 29 weight %, about 20 to about 30 weight%, about 7 to about 22 weight %, about 0 to about 8.0 weight % and about 3 to about 11 weight% respectively based on the total weight of the monomer composition of crosslinked polar nanosphere-A.
4. The dye-adsorbing polymer nanosphere composition of claim 1, wherein 100% of the crosslinked polar nanosphere-A in the aqueous dispersion form passes through 0.45 µm HPLC filters.

5. The dye-adsorbing polymer nanosphere composition of claim 1, wherein the crosslinked polar nanosphere-A is produced by using free radical microemulsion polymerization or other dispersion polymerization methods.

6. The dye-adsorbing polymer nanosphere composition of claim 1, further comprising one or more water soluble organic or water insoluble organic dye.

7. The dye-adsorbing polymer nanosphere composition of claim 6, wherein the organic dye is selected from a group consisting of fluorescent dyes, UV-absorbers, whitening compositions, color dyes, invisible dyes or a combination thereof.

8. The dye-adsorbing polymer nanosphere composition of Claim 7, wherein the amount of the
Organic dye ranges from 0.1 to 8 weight % of the weight of crosslinked polar nanosphere-A.

9. The dye-adsorbing polymer nanosphere composition of claim 8, wherein the nanosphere composition is thermally stable at 80oC for four days.
10. The dye-adsorbing polymer nanosphere composition of claim 9, wherein the composition is useful for coloring paper, leather, wood and textile fabrics such as cotton, nylon, polyester and wool.
, Description:DESCRIPTION

SURFACE-ENGINEERED CROSSLINKED NANOSPHERE FOR COATING APPLICATIONS
FIELD OF INVENTION
The present invention discloses composition, preparation and use of novel polymer nanospheres. More particularly the present invention is directed to composition and preparation of surface engineered, crosslinked, polymeric polar nanospheres, coloring of the said nanospheres and their end use in coloring of surfaces such as those of textile fabrics.
BACKGROUND OF THE INVENTION
Prior art reports reveal that adsorption of organic dye molecules over the surfaces of the nanospheres (Dye-Adsorption) and encapsulation of dye molecules during formation of polymeric particles (Dye-Encapsulation) provide viable alternatives to pigments for coloring of surfaces such as those of various textile fabrics. Both the techniques are attractive in terms of cost of raw materials, energy consumption, greater flexibility in manufacturing, effort required for coloring of surfaces and minimizing environmental pollution.
The Dye-Adsorption technique provides high dye fixation with long-term stability as compared to Dye-Encapsulation technique, where during polymerization, the polymer-dye interactions lead to a formation of a precipitate known as coagulum, especially when dye loading is more than about 3%. The choice of polymerizable unsaturated monomers influences the characteristics of the eventual polymer particles or nanospheres and their interactions with dye molecules during either dye-encapsulation or dye-adsorption. If the compositions of unsaturated monomers are in disproportion, it may lead to formation of polymer gels or hydrogel structures, which could adversely influence their performance in printed textile fabrics. Specifically, in Dye-Adsorption technique, polymer–dye interactions are structure sensitive; the polymer requires selective structural and geometrical modifications based on the type of dye. But such modifications if not done adequately and appropriately, have the potential to lead to several rheological changes, which in turn could affect aggregation of un-adsorbed dye molecules (forming crystalline structures), agglomeration of polymer nanospheres and colored polymer nanospheres (aggregates) and ultimately long-term stability. Various textile fabrics colored with inappropriately modified dispersions may face technical challenges such as poor fastness properties especially color migration, and poor quality of finished goods in terms of brightness, stiffness of fabric and fluorescence performance as revealed in the prior art references mentioned immediately below.
Patent publications, US2938873 and US3116256 disclose the Dye-Adsorption processes for obtaining colored resin particulates, where aromatic sulfonamide and formaldehyde condensates were pulverized into particulates and then colored with dye stuff. The disadvantages of these polymeric particulates appear to be a) use of hazardous formaldehyde and b) an energy intensive pulverization process.
GB822709 discloses a process for polymer particles prepared through emulsion polymerization by using unsaturated monomers, such as vinyl chloride. The polymer particles were dyed with organic dye stuff in presence of dyeing assistants such as formic acid and acetone alcohol. Further, when such colored polymer particles were applied on a textile fabric by screen printing or a pad technique method, the dye stuff was found leaching out especially on being subjected to washing with either liquor detergent or a sodium carbonate or lime. One of the limitations of the invention disclosed in ‘709 publication, is the difficulty in obtaining the colored polymer particles in concentrations, especially higher than 3% dye loading based on the total weight of polymer composition.
Patent publication, US3190850 discloses a process where a polymer particulate is composed of styrene and vinyl acetate having basic or polar groups on the surface of the particles, prepared through a graft polymerization technique and a method by which the resultant particles are dyed with acid dyes or basic dyes or direct dyes. In order to overcome poor washing performance, use of materials such as tannic acid, molybdic acid, or sodium tungstate was sought. However, such additions affected color clarity and daylight fluorescence.
Patent publication, GB770889 discloses a process for preparing a thermoplastic based pigment containing polyacrylonitrile or an acrylonitrile-based polymer and a fluorescent dye primarily for making ink or paint wherein the thermoplastic-dye combination is dispersed in a binder. Textile coloring was not part of the invention disclosed in ‘889 patent.
Patent publication, US4016133 discloses a dye-encapsulation process, where polymerization of unsaturated monomers was carried out in presence of dye stuff. Patent publication, US10494762B2 discloses a similar process, where dye stuff as one of the active ingredients, was encapsulated during microemulsion polymerization. Cotton fabrics printed with these dispersions exhibit acceptable light fastness. However, both the ‘133 and ‘762 publications are silent on a) coagulam formation if any during emulsion or microemulsion polymerization, b) color migration property related to saliva, water, perspiration and rub c) whether any melt flow occurred during baking at 150 deg C on printed cotton fabric contributing to any dye-aggregation and hence adverse aesthetic look, color and feel.
Technical challenges of the aforementioned inventions span issues such as a) avoidance of formation of coagulum, especially when dye loading is high, b) improvement of color performance of dye during application on various fabric substrates, c) improvement in fastness properties, especially related to resistance to color migration. There is a dire need for a superior and economic coloring solution which overcomes the above challenges combined with acceptable aesthetic appeal and feel of colored fabric.
In this context, the inventors have provided a practical solution to the coloring industry as disclosed in the present invention by leveraging their experience and innovative skills to overcome key technical challenges, which are assumed to be closely dependent on extent of formation of dye aggregates and extent of agglomeration of polymer nanospheres and dye-adsorbed polymer nanospheres.

SUMMARY OF INVENTION
The present invention discloses composition, preparation and use of novel polymer nanospheres. More particularly the present invention is directed to composition and preparation of surface engineered, crosslinked, polymeric polar nanospheres, coloring of the said nanospheres and their end use in coloring of surfaces such as those of textile fabrics.
The invention provides a crosslinked nanosphere composition comprising a crosslinked polar nanosphere-A, derived from monomers of Structures I, II and III, and one or more monomers selected from a group consisting of crosslink monomer-IV, graft monomer-V, monomer-VI and a combination thereof;

Structure I Structure II Structure III
Wherein R1 = H, aliphatic group of 1 to 2 carbon atoms or aromatic group;
R2 = Aliphatic group of 1 to 18 carbon atoms, HOCH2CH2- or HOCH2CH2CH2- and R3 = H or aliphatic group of 1 to 3 carbon atoms and
R4 = H or Me;
wherein the crosslink monomer-IV is selected from a group consisting of trimethylol propane trimethacrylate, trimethylolpropane (EO)n triacrylate, where n=3-15, glycerinetriacrylate, glycerine (EO)3 triacrylate, pentaerythritol triacrylate, tris(2-hydroxyethyl)isocyanurate triacrylate, pentaerythritol(EO)n tetraacrylate, ditrimethylolpropanetriacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dierythritolhexaacrylate and a combination thereof;

wherein, the graft monomer-V is selected from a group consisting of phenoxybenzylacrylate (M1122), biphenylmethylacrylate (M1192), o-phenylphenoethoxyacrylate (M1142), benzyl methacrylate, caprolactone acrylate, phenol(EO)n acrylate, where n ranges from 1 to 4, nonylphenol (EO)n acrylate, where n is either 4 or 8, ethoxyethyl acrylate, poly(EO) methoxy monoether methacrylate, where number of EO units in the poly(EO) ranges from 200 to 2000, polypropyleneglycol monomethacrylate and a combination thereof;

wherein, the monomer-VI is selected from a group consisting of acrylic acid, methacrylic acid, sodium salt of vinylsulphonic acid, sodium salt of vinylbenzene sulphonic acid or sodium salt of vinylbenzoic acid, sodium salt of 2-acrylamido-2-methyl-1-propane sulphonic acid (Na AMPS), N,N-dimethyl acrylamide, diacetone acrylamide, N-hydroxymethyl acrylamide and a combination thereof;

wherein, the crosslinked polar nanosphere-A is in the form of a colorless aqueous dispersion having solid content ranging from 1 to 25 weight%.

The dye-adsorbing polymer nanosphere composition of claim 1, wherein the amounts of monomers of structural units derived from the Structure I, the Structure II, the Structure III, the monomer-IV, the monomer-V and the monomer-VI present in the polymer nanosphere composition range from about 18 to about 29 weight%, about 18 to about 32 weight%, about 16 to about 32 weight%, about 6 to about 25 weight%, about 0 to about 15 weight% and about 2 to about 12 weight% respectively based on the total weight of the monomer composition of crosslinked polar nanosphere-A.
More particularly, the dye-adsorbing polymer nanosphere composition of claim 1, wherein the amounts of monomers of structural units derived from the structure I, the structure II, the structure III, the monomer-IV and the monomer-V present in the polymer nanosphere composition ranges from about 19 to about 26 weight %, about 20 to about 29 weight %, about 20 to about 30 weight%, about 7 to about 22 weight %, about 0 to about 8.0 weight % and about 3 to about 11 weight% respectively based on the total weight of the monomer composition of crosslinked polar nanosphere-A.
100% of the crosslinked polar nanosphere-A in the aqueous dispersion form passes through 0.45 µm HPLC filters.

The polymer nanosphere composition-A is produced by using free radical microemulsion polymerization or other dispersion polymerization methods.
The composition further comprises an aqueous dispersion of one or more water soluble organic or water insoluble organic dyes selected from the group consisting of fluorescent dyes, UV-absorbers, whitening compositions, color dyes, invisible dyes and a combination thereof. The resultant composition is free from molecular dye aggregation and agglomeration of the crosslinked polar nanosphere-A and useful for coloring textile fabrics such as cotton, nylon, polyester and wool and other surfaces such as paper, wood and leather.

The foregoing features of invention will be more readily understood by reference to the following detailed description, taken with reference to an accompanying Drawing (Figure 1).

BRIEF DESCRIPTION OF DRAWING

Figure 1. An illustration of an embodiment of dye-adsorbed crosslinked polar nanosphere of the present invention
P = Nanosphere interior - It is made of polymer based on predominantly non-polar monomer such as styrene;
Q = Polar surface - It is made predominantly of polymers based on polar monomers including acrylics and acrylic crosslinkers used in the invention;
R = Adsorbed dye molecules;
G = Graft polymer – It is made primarily of polymeric chains based on graft monomers.

DETAILED DESCRIPTION OF THE INVENTION
In the present disclosure, the expressions “coating applications” and “coloring applications” are interchangeably used.
The present invention discloses a novel crosslinked polar nanosphere-A, which is surface-engineered for efficient dye adsorption and coating of surfaces such as those of textile fabric.
The expression “surface-engineered” encompasses a) provision of polar surface of the nanosphere and/or b) provision of graft polymer chains or dispersant polymer on the surface of nanospheres for effective interaction with dye molecules. These provisions are achieved by choice of monomers and their amounts, mode of addition, timing of respective monomer additions and duration of polymerization in various stages.
In order to obtain surface polarity, the polymer nanospheres are synthesized by minimizing the weight compositions of nonpolar unsaturated monomers and hydroxyalkyl acrylic ester monomers and compensating with selected acrylates, which do not have hydroxy groups, more precisely with unsaturated monomers such as bifunctional, trifunctional, tetrafunctional or other multi-functional acrylic crosslink polar unsaturated monomers and grafting the resultant crosslinked nanospheres with mono functional monomers such as aryl-substituted acrylic ester-based unsaturated monomers in order to form the electrostatically and sterically stabilized crosslinked nanosphere, hereinafter referred to as the crosslinked polar nanosphere-A.
The grafting unsaturated monomers used in the invention form a homopolymer and certain amount of polymer-B, which become part of the crosslinked polar nanosphere-A, and is present on the surface of the crosslinked polar nanosphere-A. The aryl substituted groups present in the form of a dispersant polymer which is homopolymer or polymer-B on the surface of nanospheres are deemed to make the nanospheres interact smoothly and gently with organic dye molecules, which are priorly dissolved molecularly by using a variety of polymer dispersants in preparation of dye solutions.
In another aspect, the present invention is related to the composition of nano-sized, narrowly dispersed, highly crosslinked polar nanospheres and a process for the preparation thereof. More particularly, the present invention is directed to making a colorless polymer nanosphere dispersion having surface polarity and having superior ability to interact with organic dye stuff without forming coagulum, especially at higher dye concentrations (up to 8 weight percent to the total solid polymer) and ultimately act as ideal carrier for delivering the dye molecules to the surface of various textile fabrics such as cotton, nylon, polyester and wool and surfaces of paper, leather and wood.
The composition of the invention comprises structural units derived from several types of monomers. The terms “Functional group” of monomer refers to a polymerizable carbon-carbon double bond. For example, a monofunctional unsaturated monomer refers to an unsaturated monomer with one polymerizable carbon-carbon double bond. A multifunctional monomer refers to an unsaturated monomer with more than one polymerizable carbon-carbon double bond.
First monofunctional unsaturated monomer, having low affinity for an organic dye, hereinafter is represented by Structure I,
Second monofunctional unsaturated monomer, having one cyano group, has affinity for the dye molecule, hereinafter is represented by Structure II.
Third monofunctional unsaturated monomer is an acrylic monomer which has high affinity for dyes, hereinafter represented by Structure III,
Fourth unsaturated monomer is a crosslink multifunctional monomer-IV, for example, trimethylol propane trimethacrylate (TMPTMA).
Fifth monofunctional unsaturated monomer different from any of the monomers represented by Structures I, II and III and the crosslink monomer IV, having high ability for dispersing or dissolving the dye molecules near the vicinity of the surface of the particulates, hereinafter referred to as monomer-V, being used to graft the polymer nanospheres, which is expected to control interactions with organic dye molecules and thereby resulting in better control on aggregation of organic dye molecules and also agglomeration of colored polymer nanospheres.
Sixth monofunctional unsaturated monomer is a commonly used monomer-VI to provide electrostatic stability to polymer nanospheres formed.
The invention is further described in detail as follows.
The first unsaturated monomer, styrene (St) or alpha-methyl styrene as represented by Structure I bestows on the polymer, which it forms part of, a very low affinity for a water soluble or a water insoluble organic dye. The monomers having Formula-I may be used alone or in combination.
Polymerizable unsaturated monomers having the Structure II, have at least one “cyano” group as in the specific examples, acrylonitrile (ACN), methacrylonitrile or a combination thereof.
Polymerizable unsaturated monomer represented by Structure III is hydroxyethyl methacrylate (HEMA), hydroxypropyl methacrylate or an alkyl acrylate wherein the alkyl group has 1 to 18 carbon atoms. More particularly, the monomer represented by Structure III is selected from a group consisting of hydroxyethyl methacrylate (HEMA), hydroxypropyl methacrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, ethylhexyl acrylate, undecyl acrylate, dodecyl acrylate, stearyl acrylate and a combination thereof. The monomers of Structure III bestow on the polymer, which they form part of, high affinity for water soluble fluorescent dye molecules.

Structure I Structure II Structure III
Wherein R1 = H, aliphatic group of 1 to 2 carbon atoms or aromatic group;
R2 = Aliphatic group of 1 to 18 carbon atoms, HOCH2CH2- or HOCH2CH2CH2- and R3 = H or aliphatic group of 1 to 3 carbon atoms and
R4 = H or Me;
The aliphatic group represented by R2 can by cyclic or linear or branched or partly cyclic.
Unsaturated crosslink monomer-IV, is a multifunctional unsaturated monomer. The crosslink monomer-IV is selected from a group consisting of trimethylolpropane trimethacrylate (TMPTMA), trimethylolpropane (EO)n triacrylate (where n=3-15), glycerinetriacrylate, glycerine (EO)3 triacrylate, pentaerythritol triacrylate, tris(2-hydroxyethyl)isocyanurate triacrylate, pentaerythritol(EO)n tetraacrylate, ditrimethylolpropanetriacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate and dierythritolhexaacrylate.

The graft monomer V is selected from a group consisting of phenoxybenzylacrylate (M1122), biphenylmethylacrylate (M1192), o-phenylphenoethoxyacrylate (M1142), benzyl methacrylate, caprolactone acrylate, phenol(EO)n acrylate, where n ranges from 1 to 4, nonylphenol (EO)p acrylate, where p is either 4 or 8, ethoxyethyl acrylate, poly(EO) methoxy monoether methacrylate, where number of EO units in the poly(EO) ranges from 200 to 2000, polypropyleneglycol monomethacrylate and a combination thereof;

Preferably, the monomer-V, is selected from the group consisting of phenoxybenzyl acrylate (M1122), and o-phenylphenoxyethyl acrylate (M1142) and biphenylmethyl acrylate (M1192), as shown in some of the inventive examples of the examples section. The monomer-V may be used as a single or a mixture of two or more of the graft monomers employed for grafting the crosslinked particulates.

(M1122) (M1142) (M1192)

The monomer-V is part of the crosslinked polymer nanosphere-A and is present on the surface of crosslinked polymer nanosphere-A as a homopolymer, a polymer-B or a combination thereof; wherein, the polymer-B is derived from a combination of the monomer-V with other monomers used in the invention.

The monomer VI is selected from a group consisting of acrylic acid, methacrylic acid, sodium salt of vinylsulphonic acid, sodium salt of vinylbenzene sulphonic acid or sodium salt of vinylbenzoic acid, sodium salt of 2-acrylamido-2-methyl-1-propane sulphonic acid (Na AMPS), N,N-dimethyl acrylamide, diacetone acrylamide, N-hydroxymethyl acrylamide and a combination thereof.

The amounts of monomers of structural units derived from the Structure I, the Structure II, the Structure III, the monomer-IV, the monomer-V and the monomer-VI present in the polymer nanosphere composition range from about 18 to about 29 weight%, about 18 to about 32 weight%, about 16 to about 32 weight%, about 6 to about 25 weight%, about 0 to about 15 weight% and about 2 to about 12 weight% respectively based on the total weight of the monomer composition of crosslinked polar nanosphere-A

More particularly, the amounts of monomers of structural units derived from the Structure I, the Structure II, the Structure III, the monomer-IV, the monomer-V and the monomer-VI present in the polymer nanosphere composition ranges from about 19 to about 26 weight %, about 20 to about 29 weight %, about 20 to about 30 weight%, about 7 to about 22 weight %, about 0 to about 8.0 weight % and about 3 to about 11 weight% respectively based on the total weight of the monomer composition of crosslinked polar nanosphere-A
The preparation technique used for preparing the polymer nanosphere dispersions of the invention is a dispersion polymerization.
Preferably, the preparation technique used for preparing the polymer nanosphere dispersion is an aqueous free radical dispersion polymerization such as emulsion polymerization.
More preferably, the preparation technique used for preparing the polymer nanosphere dispersion is a free radical microemulsion polymerization.
Other dispersion polymerization methods which can be used to carry out polymerization of monomers employ a continuous phase which contains polar solvents such as isopropanol and free radical initiators such as asobisisobutyrosonitrile (AIBN).
In an embodiment, the crosslinked polymer nanospheres of the invention are used in preparing organic dye-adsorbed crosslinked polymer nanospheres useful for dyeing textile fabric surfaces.
A wide range of color dyes is available for coloring textile fabrics. Any of the color dyes belonging to the class of triphenylmethane, azo, anthraquinone, perylene and indigoid dyes can be adsorbed over the surfaces of crosslinked nanospheres of the invention to form dye adsorbed crosslinked colored nanosphere dispersions which can be used for coloring surfaces such as textile fabric surfaces. Analogous to incorporation of color dyes, other ingredients such as optical brighteners, UV-absorbers, whitening compositions, fluorescent dyes, and invisible dyes can also be surface adsorbed in the compositions of the invention.
Optical brighteners are known to compensate through their bluish fluorescence (complementary color) for greying and yellowing. They may contribute to increasing the whiteness of substrates. Examples of suitable optical brighteners include the commercially available Ultraphor® (BASF), Leucophor® (Clariant) or Tinopal® (Ciba) or other products from the chemical categories of the stilbenes, distyrylbiphenyls, coumarins, naphthalic acid imides and the benzoxazole and benzimidazole systems linked via double bonds.
UV absorbers function by absorption of damaging UV radiation. These additives generally absorb UV radiation much more strongly than the polymers that they protect. The excited states formed upon UV absorption relax to the ground state extremely rapidly and efficiently through radiation-less processes, which imparts high stabilization efficiency and excellent photostability. UV absorbers are categorized by chemical class, for example benzotriazoles, benzophenones, and triazines. Each class has its own UV absorbance characteristics. For example, benzophenone- and triazine-types tend to absorb more strongly in the short wavelength UV-B region than the benzotriazole-types. In one embodiment, any UV ray absorber that may withstand the process conditions described herein may be employed to form the polymeric UV ray absorbing composition. Suitable examples of UV ray absorber include: (a) 2-hydroxybenzophenones, (b) 2-hydroxybenzotriazoles and (c) substituted acrylonitrile and the like.
The concept behind whitening compositions is based on the principle of color cancellation to mask or alter the initial fabric color for the fabric to appear whiter. In order for masking say the yellow color of a fabric, a blue dye and violet dye is mixed in some proportion, so that appropriate color cancellation is effected and emission of multiple colors that blend to form white light results. The blue dye is selected from the group consisting of direct blue 1, direct blue 71, direct blue 80, direct blue 279, acid blue 15, acid blue 17, acid blue 25, acid blue 29, acid blue 40, acid blue 45, acid blue 75, acid blue 80, acid blue 83, acid blue 90, acid blue 113 (also known as and commercially available as Erionyl Navy R), basic blue 3, basic blue 16, basic blue 22, basic blue 47, basic blue 66, basic blue 75, basic blue 159, reactive blue 17, reactive blue 19 (also may be referred to as Remazol brilliant blue R, CI Reactive Blue 19, Remazol Br Blue BW, Remazol Navy Blue, Remazol Navy Blue RGB, and/or Remazol Br Blue BB), Cyan Blue WW-GS (also known and available as Terasil® Blue TC), and combinations thereof. The violet dye is selected from the group consisting of direct violet 7, direct violet 9, direct violet 11, direct violet 26, direct violet 31, direct violet 35, direct violet 40, direct violet 41, direct violet 48, direct violet 51, direct violet 66, direct violet 99, acid violet 9, acid violet 15, acid violet 17, acid violet 24, acid violet 43, acid violet 49, acid violet 50, basic violet 1, basic violet 3, basic violet 4, basic violet 10, basic violet 35, and combinations thereof. In a particular embodiment of the method, the violet dye is direct violet 9.
Fluorescence dyes form an important class of dyes in textile applications. Fluorescent dyes used in this invention can be water soluble dyes or water insoluble organic dyes. Preferred dyes include but are not limited to dyes selected from the classes of benzothioxanthane, xanthane, coumarin, naphthalimide, benzoxanthane, perylene, and acridine. Examples of water-soluble dyes which may be used include the sulfonate and carboxylate dyes, specifically, those that are commonly employed in ink-jet printing. Specific examples include: Sulforhodamine B (sulfonate), Acid Blue 113 (sulfonate), Acid Blue 29 (sulfonate), Acid Red 4 (sulfonate), Rose Bengal (carboxylate), Acid Yellow 17 (sulfonate), Acid Yellow 29 (sulfonate), Acid Yellow 42 (sulfonate), Acridine Yellow G (sulfonate), Nitro Blue Tetrazolium Chloride Monohydrate or Nitro BT, Rhodamine 6G, Rhodamine 123, Rhodamine B, Rhodamine B Isocyanate, Safranine O, Azure B, Azure B Eosinate, Basic Blue 47, Basic Blue 66, Thioflacin T (Basic Yellow 1), and Auramine O (Basic Yellow 2), all available from Aldrich Chemical Company. Examples of water-insoluble dyes which may be used include azo, xanthene, methine, polymethine, and anthroquinone dyes. Specific examples of water-insoluble dyes include Ciba-Geigy Orasol Blue GN, Ciba-Geigy Orasol Pink, Ciba-Geigy Orasol Yellow, Lumogen™ fluorescent dyes from BASF, and the like.
In another embodiment, invisible dyes may be incorporated in the polymer nanosphere compositions of the invention. Invisible dyes are used as color markers which show up as striking colors on exposure to UV light or in some cases IR and in some other cases Far IR rays. Under normal light, they generally are not colored. Invisible dyes are also called fluorophores. The term “fluorophore” generally involves a chemical composition which is capable of absorbing light and thereafter emitting fluorescent light upon excitation with light of a given wavelength. Representative materials in each of these classes are as follows: (1) stilbenes: 4,4'-bis(triazin-2-ylamino)stilbene-2,2'-disulfonic acid; benzenesulfonic acid-2,2'-(1,2-ethenediyl)bis[5-[4-bis(2-hydroxyethyl)amino]-6-[(4-sulfophenyl)amino]-1,3,5-triazin-2yl]amino-tetrasodium salt; and 4,4-bis [4-diisopropanolamino-6-(p-sulfoanilino)-s-triazin-2-yl-amine]stilbene-sodium disulfonate; (2) pyrazolines: 1,2-diphenyl-2-pyrazoline; (3) coumarins: 7-diethylamino-4-methylcoumarin; 7-hydroxy-4-methylcoumarin; and 3-(2-benzimidazolyl)-7-(diethylamino)coumarin; (4) carbostyrils: 2-hydroxyquinoline; and (5) pyrenes: N-(1-pyrenebutanoyl)cysteic acid. Also of interest as an ultraviolet fluorophore is dibenzothiophene-5,5-dioxide, as well as C.I. (Color Index) Fluorescent Brightener 28; C.I. Fluorescent Brightener 220; and C.I. Fluorescent Brightener 264, with some or all of these C.I. compositions being comparable or structurally equivalent to the specific materials listed above. The foregoing ultraviolet fluorophores and others are commercially available from numerous sources including but not limited to the Aldrich Chemical Co. of Milwaukee, Wis. (USA); Bayer Corporation of Pittsburgh, Pa. (USA) under the names “BLANKOPHORE” or “PHORWHITE”; Ciba-Geigy Corporation of Greensboro, N.C. (USA)/Basil, Switzerland; Molecular Probes of Eugene, Oreg. (USA); Sandoz Chemicals of Charlotte, N.C. (USA) under the name “LEUKOPHOR”; and Sigma Co. of St. Louis, Mo. (USA). These materials are characterized by their ability to generate fluorescent light upon ultraviolet illumination and can be seen by the unaided eye.

MATERIALS
Polyvinyl alcohol (PVA, (Grade: Poval 203) was procured from Dorado Chem Private Limited, 302, Sunil Enclave, Pereira Hill Road, Off Western Express Highway, Andheri Kurla Road, Andheri 400099, Mumbai, India and used as received.
2-acrylamido-2-methylpropane sulphonic acid sodium salt (Na-AMPS), 50% aqueous solution, was procured from Vinati Organic Limited, Bandra-Kurl Complex, Mumbai (East)-51 was used as received.
Ammonium lauryl sulphate was procured from SD Fine Chemicals and used as received.
Ammonium persulphate (APS), 98.0% purity, sodium metabisulphite (SMBS), 95.01% Purity, and ACN, 98% purity were procured from SD Fine Chemicals.
HEMA, 98% purity, styrene, 98% purity, trimethylol propane trimethacrylate, 98% purity and rhodamine 6G were procured from ChemPure Private Limited, Jigani 560105, Bangalore.
Acrylic ester monomers, M1192, M1122 & M1142 were procured from Miwon, Head Quarters, 20, Poeum-Daero, 59Beon-Gil, Suji-gu, Yongin-Si, Gyeon-ggi; 16864; Korea and used as received.
Deionized water with resistivity of ~18 M? cm was used as inert medium for all synthesis of fluorescent dispersions.
High molecular weight chitosan was procured from Everest Biotech, #39, SLV Plaza, 3rd Floor, Bulltemple Road, Basavanagudi, Bangalore 560004.
EO/PO polymer block, Product EP3100 (g) was procured from Esteem Industries Private Limited, Plot No.115, Bicholim Industries Estate, Bicholim 403529, Goa, India and used as received.
Borges Canola Oil, Borges Agricultural & Industrial Edible Oils, SAU, Avda>Josep Trepats/n 25300, Tarrega, Spain, was used as received.
Bentonite clay procured from Mekasa products private limited C-47, East of Kailash, New Delhi, was used as received.
Kadpol 940, from Shree chemicals, Plot No. 3495, Phase -4, GIDC, Chhatral 382729, Gujarat, was used as received.
Textile cotton woven fabric (100%) having construction of 23.6 ends/cm2 with an area density of 112.2 g/m2 was used as fabric for printing. (Matic, PO Box 14760, Mumbai 400099)
Detergent Surf excel, procured was used as received.
The other chemicals, otherwise not specified, are of LR grade, and used as received.
EXAMPLES
I. Preparation of crosslinked polar nanosphere-A
General Method: As in a typical emulsion or microemulsion polymerization system, a water-soluble initiator system, preferably a redox initiator system, is used. Surfactant system employed includes ionic and non-ionic surfactants used in the industry. Preferably, an anionic surfactant system is employed. Additionally, any emulsion stabilizer, preferably polyvinyl alcohol, is used as emulsion stabilizer. Addition of monomers either individually or as a mixture is generally done continuously in one lot or in different lots. A premixture of monomers is initially introduced to form the nucleus particles, after which the rest of the monomer mixtures is added to grow and form particles. Like the addition of monomers, addition of redox initiator solution is also done continuously in one lot or in different lots. The monomer addition time and initiator addition time can be in the range between 30 min to 120 hours. Graft monomers are generally included among the final lots of monomer addition. Ionic monomers such as Na AMPS can be introduced at any juncture during the polymerization. Use of ultrasonic bath to control the droplet size is typical of microemulsion polymerization technique, which is adopted in the preparation of the nanosphere of the invention. Towards the end of polymerization, initiators such as tert-butyl hydroperoxide is added to polymerize any residual monomers. The solid content of the nanosphere dispersions of the invention were within ±1.5 weight% of theoretical solids the calculation of which is based on complete polymerization of monomers and amounts of other solid additives present in the dispersion. Other process steps employed are typical of any emulsion or microemulsion or other dispersion polymerization techniques.
Measurements
Solid contents of the crosslinked polar nanosphere dispersions of the invention were measured by weighing (0.5g) of the nanosphere dispersion into Borosilicate glass Petri dish (40X15 mm2) and placing in a preheated oven at 120°C for 30 minutes. The dish was then taken out and placed in a glass desiccator and allowed to come to room temperature. The percent solid was calculated after weighing the dish. The solid content data are presented in Table 2.
The method of particle size measurement was based on the verification that 100% of the aqueous dispersions of crosslinked polar nanosphere of the inventive examples pass through a 0.45µ HPLC filter and assigning particle size of the crosslinked polar nanosphere of the invention as less than 0.45 µ.

Table 1: Composition of Nanosphere of Comparative Examples 1-2 and
Inventive Examples 3-6, 5A and 6A

Comparative Examples 1 to 2 and Example 3:
A 1000 ml five-neck round-bottom flask equipped with a reflux condenser, stainless steel stirrer and two separate feed streams were used to carry out microemulsion free radical polymerization. Oxygen was removed by purging high purity nitrogen gas into the specified quantity of demineralised (DM) water (290 g) transferred into the five-neck round-bottom flask. Then emulsifying agent, ammonium lauryl sulphate (10.00 g) and hot melt PVA (Poval 203, 0.20 g) were added and stirring was continued for around 30 minutes under a blanket of nitrogen at 80°C. After this, the temperature was gradually allowed to reach room temperature. Aqueous solution of Na AMPS (8.00 g) was then added to the reaction mixture followed by a premixture (12.00 g) taken from monomer feed mixture, prepared by mixing the monomers, St, ACN, HEMA and TMPTMA in amounts as given in Table 1. An aqueous initiator solution prepared by dissolving APS (0.19 g) and SMBS (0.04 g) in DM water (10.00 g) was charged into the reaction flask and stirred under ultra-sonic bath for 40 minutes. The remaining monomer feed mixture was split into 8 lots and added slowly for a period of 8 hours. In parallel, an aqueous initiator solution prepared by dissolving APS (0.47 g) and SMBS (0.11 g) in DM water (60.00 g) was charged into the reaction flask over a period of 8 hours. After completion of addition of four lots of the monomer feed mixture, the specified quantity (see Table 1) of monomer-V was added to the balance four lots of the monomer feed mixture and the polymerization was further continued at the same temperature. After completion of two hours, tert-butyl hydroperoxide (1.0 g) was added and the polymerization was further continued for another 2 hours. The resultant dispersion was allowed to cool to room temperature and then filtered through using stainless steel fine mesh strainer sieve colander 7-5/8 inch to separate coagulum formed during microemulsion polymerization. The resultant dispersion was preserved at room temperature under airtight caps. The solid contents of the dispersions are shown in Table 2.

Examples 4 and 5:
A 1000 ml five-neck round-bottom flask equipped with a reflux condenser, stainless steel stirrer and two separate feed streams were used to carry out microemulsion free radical polymerization. Oxygen was removed by purging high purity nitrogen gas into the specified quantity of demineralised (DM) water (350 g) transferred into the five-neck round-bottom flask. Then emulsifying agent, ammonium lauryl sulphate (10.00 g) and hot melt PVA (Poval 203, 0.20 g) were added and stirring was continued for around 30 minutes under a blanket of nitrogen at 80°C. After this, the temperature was gradually allowed to reach room temperature. Aqueous solution of Na AMPS (8.00 g) was then added to the reaction mixture followed by a premixture (12.00 g), taken from monomer feed mixture, prepared by mixing the monomers, St, ACN, HEMA and TMPTMA in amounts as given in Table 1. An aqueous initiator solution prepared by dissolving APS (0.19 g) and SMBS (0.04 g) in DM water (10.00 g) was charged into the reaction flask and stirred under ultra-sonic bath for 40 minutes. The remaining monomer feed mixture was split into 8 lots and added slowly for a period of 8 hours. In parallel, an aqueous initiator solution prepared by dissolving APS (0.47 g) and SMBS (0.11 g) in DM water (60.00 g) was charged into the reaction flask over a period of 8 hours. After completion of addition of four lots of the monomer mixture, the specified quantity (see Table 1) of monomer-V was added to the balance four lots of the monomer mixture and the polymerization was further continued at the same temperature. In the case of Example 5, monomer-V was not included and the feed mixture was continued as such. After completion of two hours, tert-butyl hydroperoxide (1.0 g) was added and the polymerization was further continued for another 2 hours. The resultant dispersion was allowed to cool to room temperature and then filtered through using stainless steel fine mesh strainer sieve colander 7-5/8 inch to separate coagulum formed during microemulsion polymerization. The solid contents of the dispersions are shown in Table 2.

Example 5A:
The procedure for preparation for the crosslinked nanosphere, Example 5A was identical to that for Example 5, excepting for the inclusion of monomer-V (M1142) (see Table 1). The juncture of addition of the monomer-V in the polymerization procedure of Example 5A was similar to that for Example 4. The properties are shown in Table 2.

Examples 6
A 1000 ml five-neck round-bottom flask equipped with a reflux condenser, stainless steel stirrer and two separate feed streams were used to carry out microemulsion free radical polymerization. Oxygen was removed by purging high purity nitrogen gas into the specified quantity of demineralised (DM) water (450 g) transferred into the five-neck round-bottom flask. Then emulsifying agent, ammonium lauryl sulphate (10.00 g) and hot melt PVA (Poval 203, 0.20 g) were added and stirring was continued for around 30 minutes under a blanket of nitrogen at 80°C. After this, the temperature was gradually allowed to reach room temperature. Aqueous solution of Na AMPS (8.00 g) was then added to the reaction mixture followed by a premixture (12.00 g), taken from monomer feed mixture, prepared by mixing the monomers, St, ACN, HEMA and TMPTMA in amounts as given in Table 1. An aqueous initiator solution prepared by dissolving APS (0.19 g) and SMBS (0.04 g) in DM water (10.00 g) was charged into the reaction flask and stirred under ultra-sonic bath for 40 minutes. The monomer feed mixture was then split into 3 lots and added slowly for a period of 3 hours. In parallel, an aqueous initiator solution prepared by dissolving APS (0.47 g) and SMBS (0.11 g) in DM water (30.00 g) was charged into the reaction flask over a period of 3 hours. After completion of two hours, tert-butyl hydroperoxide (1.0 g) was added and the polymerization was further continued for another 2 hours. The resultant dispersion was allowed to cool to room temperature and then filtered through using stainless steel fine mesh strainer sieve colander 7-5/8 inch to separate coagulum formed during microemulsion polymerization. The solid content of the dispersion is shown in Table 2.
Example 6A
The procedure for preparation for the crosslinked nanosphere, Example 6A was identical to that for Example 6, excepting for the inclusion of monomer V (M1142) (see Table 1). The juncture of addition of the monomer V in example 6A was similar to that for Example 4. The properties are shown in Table 2.
In the free radical microemulsion polymerization of the invention, during continuous addition of the feed, hydrophobic or nonpolar unsaturated monomers present in the feed monomer mixture move towards the centre of forming nanospheres, while the polar unsaturated monomers move towards the surface of the nanospheres and thus forming the surface polar. In the current invention, crosslinked polar nanospheres were synthesized by reducing largely the weight compositions of nonpolar unsaturated monomers and substituting them with multifunctional crosslink unsaturated monomers. An example of nonpolar monomers used in the invention is styrene or alpha-methyl styrene. Even though reduction in the weight compositions of styrene is expected to have impact on reducing the glass transition temperature of the resultant crosslinked nanospheres, this impact was nullified in the new invention by compensating the reduction with multifunctional crosslink acrylic unsaturated polar monomers.
In the case of compositions with high weight proportions of aliphatic hydroxyalkyl acrylic esters, the hydroxyl groups affect the interactions of nanospheres through formation of Vander Walls forces and inter macromolecular hydrogen bonding, which ultimately leads to agglomeration of nanospheres. Even though these hydroxyalkyl acrylic unsaturated monomers contribute to a great extent by conferring the desired surface polarity on the polymer nanospheres, the undesired agglomeration of these polymer nanospheres results in poor and nonuniform interactions with organic dye molecules during coloring process. In the current invention, the crosslinked nanospheres are designed and developed by using relatively lower weight proportions of these aliphatic hydroxyalkyl acrylic ester monomers.

Table 2: Properties of Nanosphere dispersions of Comparative examples 1-2 and inventive Examples 1-6, 5A and 6A
Example
? Comparative Example 1 Comparative Example 2 Example 3 Example 4 Example 5 Example 6 Example 5A Example 6A
pH @250C 3.00 3.43 3.96 3.54 4.10 3.95 4.3 3.8
Particle Size, Dv100 (µm) < 0.45 < 0.45 < 0.45 < 0.45 < 0.45 < 0.45 < 0.45 < 0.45
Viscosity by Ford Cup No.4@ 250C 14 14 12 11 11 11 11 11
Solid Content* weight % 19.6 19.2 18.7 15.7 15.1 7.5 15.7 8.1
*(0.5 g / 1500C; 30 minutes (±1.0%))

Addition of the acrylic aryl substituted ester monomers, M1192, M1122 and M1142, either during the end of addition of feed monomer mixtures or later, results in grafting around the surface of the nanospheres. Grafting with these monomers which contain aryls or phenoxyaryl groups, is expected to stabilize the nanospheres sterically and also expected to enable soft interactions with the organic dyes, near the vicinity of the surface of these nanospheres. It is also expected to increase the solubility of the dye molecules molecularly before interacting with the surface of the nanospheres.
In order to study thermal stability of the dispersions containing colored crosslinked nanospheres, (see Examples 7-12 for its preparation), the colored dispersion samples were placed in a preheated oven at 80oC for four days and then the resultant thermally treated dispersions were found quite stable and found passing through 0.45 µm HPLC filters without any semblance of formation of coagulum. The thermal stability observed indicates that in the present system, the aggregation of dye molecules and agglomeration of the colored crosslinked nanospheres is controlled as desired.

II. Preparation of colored crosslinked nanosphere dispersions
Example 7:
To DM Water (100 g), high molecular weight water soluble chitosan (0.25 g) was dissolved under ultrasonic bath for around 2 minutes. To the chitosan solution, sodium lauryl ether sulphate (0.2 g) was added and continued sonication for another 2 minutes, followed by addition of EO/PO copolymer block, EP3100 (0.2 g) and ultrasonication was continued for another 2 minutes. To the resulting solution, Rhodamine 6G (1.0 g) was added and sonicated for around 5 minutes after which the dye solution was added slowly to the crosslinked polar nanosphere-A in aqueous dispersion form (100 g) (as such from Example 1) and mixed at room temperature for 15 minutes to form a colored nanosphere dispersion which is then subjected to drying by employing a rotary evaporator at 680 mm Hg to obtain a dispersion with solids content of around 40 weight %, consistent with a general procedure wherein, solid content of such colored crosslinked nanosphere dispersions is generally maintained in the range of 40 to 50 weight%. Further, the dye-loading in Example 7 measures to about 5 weight% of the solid crosslinked polar nanosphere composition.
The resultant fluorescent dispersions were evaluated by printing on cotton fabrics and measuring light and wash fastness properties. An acrylic thickener prepared in accordance to the procedure described in US Patent 2004/0102553A1 was used to prepare the printing paste.

Examples 8 to 12:
Colored crosslinked nanosphere dispersions of Examples 8 to 12 were prepared according to the procedure identical to that of Example 7 except for the crosslinked polar nanosphere-A dispersion. In the case of Examples 8 and 9, the crosslinked nanosphere dispersions of Examples 2 and 3 were used respectively as such. However, in the case of Examples 10, 11 and 12, prior to the preparation of colored crosslinked nanosphere dispersions, the solid content of the crosslinked nanosphere dispersions of Examples 4, 5 and 6 were adjusted to 19±1% by subjecting the samples from microemulsion polymerisation to a rotovaporator. As in Example 7, the colored crosslinked nanosphere dispersions of Examples 8 to 12 were further adjusted to solid content of around 40 weight % prior to evaluation by printing on cotton fabric.

Example 13:
Colored crosslinked nanosphere dispersion of Examples 13 was prepared according to the procedure identical to that of Example 7 except for the crosslinked polar nanosphere-A. In the case of Example 13, the crosslinked nanosphere-A of Examples 5 and 6 were used at 85:15 weight percent ratio respectively as such. Prior to the preparation of color, the solid content of the crosslinked nanosphere-A was adjusted to 19±1% by subjecting the samples from microemulsion polymerisation to partial removal of water using a rotovaporator.

In the current invention, cloth prints of 50X150 mm2 were taken by using screen print method. The fastness properties of the printed cotton fabrics depend upon percentage of pigments used in the printing pastes, type of the binders and thickeners being used in the preparation of pastes, solid contents of the pigments or dispersions, pH, type and their weight percentages of unsaturated monomers being used in the free radical emulsion polymerization, other additives or ingredients being used in the preparation of printing pastes. Generally, the color migration or bleeding properties increases proportionally with increasing the percentage of pigment or dispersion in the printing paste. To evaluate the performance of light fastness, wash fastness and color migration, in the current invention, cotton fabrics were printed at 3 weight % of fluorescent dispersions.
One of the major limitations in the prior art inventions reported is the difficulty in meeting the desired high tinctorial strengths, which could be due to formation of larger quantities of coagulum during the free radical microemulsion polymerization in the presence of dye. One of the specific solutions of the inventors is avoiding polymerization of unsaturated monomers in the presence of dyestuff. Many organic dyes used for making fluorescent pigments or dispersions are based on ionic dyes or polar pigment dyes, which are rich in p-conjugation. They form electrolyte solutions, when dissolved in water. When free radical polymerization is carried out in presence of organic fluorescent dyes, it results in formation of coagulum, reducing the yields of the fluorescent dispersions and increasing the overall cost. Additionally, obtaining higher tinctorial strengths is difficult as formation of coagulum increases. Hence efforts of the inventors were to avoid situations that lead to such coagulum formation.
In the current invention, the preparation of dye solution for coloring of the crosslinked nanospheres is carried out by dispersing a water dispersible organic fluorescent dye in water with or without a surface-active agent and then mixing the dye solution with the crosslinked nanosphere dispersion of the invention. No coagulum formation was observed when dye stuff is adsorbed over the crosslinked nanospheres. A surface-active agent is used for preparing a solution. Such a surface-active agent can be a polymeric dispersing agent which can be added along with the dye stuff to dissolve and disperse the dye molecularly for interacting with the polymer nanospheres. The surface-active agent is selected from the group consisting of sodium polyoxy ethylene alkyl sulphate, sodium polyoxy ethylene alkyl phenol sulphate, condensate products of naphthalene sulphonic acid or a nonylphenol ethoxylate, alkali metal salts of dodecyl benzene sulphonic acid, nonionic surfactants such as fatty acid ethoxylates, fatty alcohol ethoxylates, EO/PO block copolymers and a combination thereof.
Preparation of Materials for printing on textile fabric & Measurements
Thickener paste was prepared in accordance to US Patent 2004/0102553A1, using Cadpol 940 and canola oil and Tween 20 as emulsifier. To the resultant thickener (3.0 g), DM water (85.5 g) was added and mixed gently for 15 minutes at 180 rpm and after 15 minutes, liquor ammonia (0.5 g) was added and mixed slowly for another 15 minutes. The resultant paste (9.0 g) was mixed with the newly synthesized fluorescent dispersions and then soaked for about 12 hours. After the printing paste was applied to the cotton fabrics by using printing pad method and then baked at 150°C for 5 minutes. The printed cotton fabrics were cut into the dimensions of 110X60 mm2 and then subjected to analysis.
In order to measure light fastness, the specimen of dimensions of 25X50 mm2 were exposed to natural sunlight in comparison to cloth prints of Comparative Example 1 for 8 hours. After the exposure to light, the cotton fabrics were taken and then scanned with Premier Color Scan Spectrophotometer to measure the variations in both strength and shade (dE*) and were as tabulated in Table 3).
In order to measure washing performance, Surfexcel solution (2.0 weight percent) was prepared in DM water. To the solution (20 times to the weight of the printed cotton fabric) weighed into a conical flask, the specimen was added and rinsed at 60°C for 10 minutes. Then after the fabric was rinsed two times with DM water (each time 5 minutes with 25 ml DM water), it was squeezed and dried in an oven at 100°C. The dried cotton fabric samples were then scanned with the Spectrophotometer to measure the variations both in strength and shade (dE*). The results are given in Table 3.

Table 3: Evaluation of performance of colored nanosphere dispersions of the invention
Colored nanosphere dispersion used for making printing paste to be applied on textile fabric surface Corresponding crosslinked polar nanosphere dispersion used Light Fastness Wash Fastness Color Migration
dE Strength% dE Strength % dE Strength %
Comparative Example 7 Comparative Example 1 5.0 70 4.5 72 3.5 100
Comparative Example 8 Comparative Example 2 5.0 75 4.0 70 3.0 95
Example 9 Example 3 6.0 90 3.5 75 2.0 80
Example 10 Example 4* 5.5 92 3.3 78 2.5 80
Example 11 Example 5* 5.8 85 4.0 75 3.0 78
Example 12 Example 6* 5.3 80 4.3 75 3.2 77
Example 13 Example 5 & 6A* (85:15) weight % 3 94 2.5 85 2.2 82
*Water amount was adjusted by partial water removal using a rotovaporator such that solid content of dispersion was 19 ± 1% prior to preparation of colored nanosphere.
In order to measure color migration, Surfexcel solution (2.0 weight percent) was prepared in DM water. After cutting printed cotton fabric samples to the specific dimensions, the unprinted cotton fabrics of 60X25 mm2 were cut and both were placed in the conical flask and the detergent solution (20 times to the weight of the printed cotton fabric) was transferred and then rinsed at 60°C for 10 minutes. Then after the two cotton fabrics were rinsed two times with DM water (each time 5 minutes with 25 mL DM water), they were squeezed and dried in the oven at 100°C for 5 minutes. The dried unprinted cotton fabrics of 60X25 mm2 were scanned with Premier Color Scan Spectrophotometer to measure the variations both in strength and shade (dE*) with reference to unprinted cotton fabric. The dE and Strength% values of the unprinted cotton fabric sample are shown in Table 3.
As per the inventive Examples 3 to 6, the major objective of the current invention is to design and develop crosslinked nanosphere dispersion with relatively increased crosslink density by incorporating higher weight compositions of multifunctional crosslink monomers and increasing the polarity of the surface of the polymer nanospheres, which can interact with the organic dye for better binding affinity and for better delivery of molecularly dissolved dye molecules to the surface of the textile fabric. In addition to this, the purpose of increasing the crosslink density of the nanospheres is that during the baking at 1500C of printed cotton fabrics, shifting the glass transition temperature of the crosslinked nanospheres relatively to higher side allows the dye to bind to cotton fabric as well as resulting in enhanced washing performance and color migration performance.
In the current invention, the weight compositions of acrylic esters containing hydroxyalkyl groups and also monomers having -C=N functional groups are so chosen that they reduce greatly the probability of formation of intermacromolecular hydrogen bonding thereby greatly reducing aggregation of dye molecules and also agglomeration of the corresponding colored crosslinked nanospheres. The use of crosslink acrylic ester monomers increases crosslink density of the resultant nanospheres and thereby it exhibits resistance to melt-flow during baking at 1500C of printed cotton fabrics. The cotton fabrics printed with fluorescent dispersions of inventive examples exhibit relatively better fluorescence visually, light fastness and wash fastness, and controlled color migration or bleeding and are expected to satisfy the desired textile properties adequately.
All the inventive Examples 9 to 12, demonstrate superior balance of performance in light-fastness, wash-fastness and color migration characteristics relative to the dye-encapsulated system represented by Comparative Examples 1-2.
Out of the various weight compositions of HEMA and ACN as specified in Examples 3 to 6, the crosslinked nanospheres dispersions prepared with nearly equi-weights of St, ACN and HEMA along with increased weight of crosslink unsaturated monomer particularly in Examples 3 to 6 corresponding to the colored nanospheres of Examples 9 to 12, show improved wash fastness and controlled color migration relative to those of Comparative Examples 1-2
In Examples 9 and 10, the printed cotton fabrics showed relatively better washing fastness performance and control on color migration. We attribute this result to the relatively reduced weight compositions of ACN and HEMA resulting in reduced inter macromolecular interactions to allow the dye molecules to diffuse uniformly over the nanosphere surface, which results in better control of either self-aggregation of dye molecules or agglomeration of nanospheres or colored nanospheres.
In the case of Comparative Examples 1-2, the measurements of shade change and strength of unprinted cloth specimen, indicate relatively higher color migration which could be due to presence of higher weight proportions of CAN and HEMA in the polymer.
In the case of inventive Examples 11 and 12 based on the nanospheres of Example 5 and 6 having no graft monomer, the color migration property was seen similar to the other inventive examples possibly due to judiciously enhanced proportion of crosslink monomer.
Example 13 provides an example to achieve excellent performance in light fastness, wash fastness and color migration properties by blending two or more nanosphere compositions of varying proportions of graft monomer and crosslink monomers in the monomer composition.
The inventors have provided a novel crosslinked polar nanosphere composition that affords higher tinctorial strengths, acceptable light fastness and wash fastness and resistance to color migration on textile surface.