Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G9/00—Developers
  • G03G9/08—Developers with toner particles
  • G03G9/093—Encapsulated toner particles
  • G03G9/09307—Encapsulated toner particles specified by the shell material
  • G03G9/09314—Macromolecular compounds
  • G03G9/09328—Macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06P—DYEING OR PRINTING TEXTILES; DYEING LEATHER, FURS OR SOLID MACROMOLECULAR SUBSTANCES IN ANY FORM
  • D06P1/00—General processes of dyeing or printing textiles, or general processes of dyeing leather, furs, or solid macromolecular substances in any form, classified according to the dyes, pigments, or auxiliary substances employed
  • D06P1/44—General processes of dyeing or printing textiles, or general processes of dyeing leather, furs, or solid macromolecular substances in any form, classified according to the dyes, pigments, or auxiliary substances employed using insoluble pigments or auxiliary substances, e.g. binders
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06P—DYEING OR PRINTING TEXTILES; DYEING LEATHER, FURS OR SOLID MACROMOLECULAR SUBSTANCES IN ANY FORM
  • D06P1/00—General processes of dyeing or printing textiles, or general processes of dyeing leather, furs, or solid macromolecular substances in any form, classified according to the dyes, pigments, or auxiliary substances employed
  • D06P1/44—General processes of dyeing or printing textiles, or general processes of dyeing leather, furs, or solid macromolecular substances in any form, classified according to the dyes, pigments, or auxiliary substances employed using insoluble pigments or auxiliary substances, e.g. binders
  • D06P1/52—General processes of dyeing or printing textiles, or general processes of dyeing leather, furs, or solid macromolecular substances in any form, classified according to the dyes, pigments, or auxiliary substances employed using insoluble pigments or auxiliary substances, e.g. binders using compositions containing synthetic macromolecular substances
  • D06P1/5207—Macromolecular compounds obtained by reactions involving only carbon-to-carbon unsaturated bonds
  • D06P1/5214—Polymers of unsaturated compounds containing no COOH groups or functional derivatives thereof
  • D06P1/5221—Polymers of unsaturated hydrocarbons, e.g. polystyrene polyalkylene
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06P—DYEING OR PRINTING TEXTILES; DYEING LEATHER, FURS OR SOLID MACROMOLECULAR SUBSTANCES IN ANY FORM
  • D06P1/00—General processes of dyeing or printing textiles, or general processes of dyeing leather, furs, or solid macromolecular substances in any form, classified according to the dyes, pigments, or auxiliary substances employed
  • D06P1/44—General processes of dyeing or printing textiles, or general processes of dyeing leather, furs, or solid macromolecular substances in any form, classified according to the dyes, pigments, or auxiliary substances employed using insoluble pigments or auxiliary substances, e.g. binders
  • D06P1/52—General processes of dyeing or printing textiles, or general processes of dyeing leather, furs, or solid macromolecular substances in any form, classified according to the dyes, pigments, or auxiliary substances employed using insoluble pigments or auxiliary substances, e.g. binders using compositions containing synthetic macromolecular substances
  • D06P1/5207—Macromolecular compounds obtained by reactions involving only carbon-to-carbon unsaturated bonds
  • D06P1/5214—Polymers of unsaturated compounds containing no COOH groups or functional derivatives thereof
  • D06P1/5228—Polyalkenyl alcohols, e.g. PVA
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06P—DYEING OR PRINTING TEXTILES; DYEING LEATHER, FURS OR SOLID MACROMOLECULAR SUBSTANCES IN ANY FORM
  • D06P1/00—General processes of dyeing or printing textiles, or general processes of dyeing leather, furs, or solid macromolecular substances in any form, classified according to the dyes, pigments, or auxiliary substances employed
  • D06P1/44—General processes of dyeing or printing textiles, or general processes of dyeing leather, furs, or solid macromolecular substances in any form, classified according to the dyes, pigments, or auxiliary substances employed using insoluble pigments or auxiliary substances, e.g. binders
  • D06P1/52—General processes of dyeing or printing textiles, or general processes of dyeing leather, furs, or solid macromolecular substances in any form, classified according to the dyes, pigments, or auxiliary substances employed using insoluble pigments or auxiliary substances, e.g. binders using compositions containing synthetic macromolecular substances
  • D06P1/5207—Macromolecular compounds obtained by reactions involving only carbon-to-carbon unsaturated bonds
  • D06P1/5214—Polymers of unsaturated compounds containing no COOH groups or functional derivatives thereof
  • D06P1/5242—Polymers of unsaturated N-containing compounds
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06P—DYEING OR PRINTING TEXTILES; DYEING LEATHER, FURS OR SOLID MACROMOLECULAR SUBSTANCES IN ANY FORM
  • D06P1/00—General processes of dyeing or printing textiles, or general processes of dyeing leather, furs, or solid macromolecular substances in any form, classified according to the dyes, pigments, or auxiliary substances employed
  • D06P1/44—General processes of dyeing or printing textiles, or general processes of dyeing leather, furs, or solid macromolecular substances in any form, classified according to the dyes, pigments, or auxiliary substances employed using insoluble pigments or auxiliary substances, e.g. binders
  • D06P1/52—General processes of dyeing or printing textiles, or general processes of dyeing leather, furs, or solid macromolecular substances in any form, classified according to the dyes, pigments, or auxiliary substances employed using insoluble pigments or auxiliary substances, e.g. binders using compositions containing synthetic macromolecular substances
  • D06P1/5207—Macromolecular compounds obtained by reactions involving only carbon-to-carbon unsaturated bonds
  • D06P1/525—Polymers of unsaturated carboxylic acids or functional derivatives thereof
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06P—DYEING OR PRINTING TEXTILES; DYEING LEATHER, FURS OR SOLID MACROMOLECULAR SUBSTANCES IN ANY FORM
  • D06P1/00—General processes of dyeing or printing textiles, or general processes of dyeing leather, furs, or solid macromolecular substances in any form, classified according to the dyes, pigments, or auxiliary substances employed
  • D06P1/44—General processes of dyeing or printing textiles, or general processes of dyeing leather, furs, or solid macromolecular substances in any form, classified according to the dyes, pigments, or auxiliary substances employed using insoluble pigments or auxiliary substances, e.g. binders
  • D06P1/52—General processes of dyeing or printing textiles, or general processes of dyeing leather, furs, or solid macromolecular substances in any form, classified according to the dyes, pigments, or auxiliary substances employed using insoluble pigments or auxiliary substances, e.g. binders using compositions containing synthetic macromolecular substances
  • D06P1/5207—Macromolecular compounds obtained by reactions involving only carbon-to-carbon unsaturated bonds
  • D06P1/525—Polymers of unsaturated carboxylic acids or functional derivatives thereof
  • D06P1/5257—(Meth)acrylic acid
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06P—DYEING OR PRINTING TEXTILES; DYEING LEATHER, FURS OR SOLID MACROMOLECULAR SUBSTANCES IN ANY FORM
  • D06P1/00—General processes of dyeing or printing textiles, or general processes of dyeing leather, furs, or solid macromolecular substances in any form, classified according to the dyes, pigments, or auxiliary substances employed
  • D06P1/44—General processes of dyeing or printing textiles, or general processes of dyeing leather, furs, or solid macromolecular substances in any form, classified according to the dyes, pigments, or auxiliary substances employed using insoluble pigments or auxiliary substances, e.g. binders
  • D06P1/52—General processes of dyeing or printing textiles, or general processes of dyeing leather, furs, or solid macromolecular substances in any form, classified according to the dyes, pigments, or auxiliary substances employed using insoluble pigments or auxiliary substances, e.g. binders using compositions containing synthetic macromolecular substances
  • D06P1/54—Substances with reactive groups together with crosslinking agents
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G9/00—Developers
  • G03G9/08—Developers with toner particles
  • G03G9/093—Encapsulated toner particles
  • G03G9/0935—Encapsulated toner particles specified by the core material
  • G03G9/09357—Macromolecular compounds
  • G03G9/09371—Macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G9/00—Developers
  • G03G9/08—Developers with toner particles
  • G03G9/093—Encapsulated toner particles
  • G03G9/09392—Preparation thereof

Definitions

• the present invention relates to a core-shell type binder for pigment printing, a paste comprising such binder, and a method of production thereof.
• the coating composition for pigment printing includes an emulsion of conventional or in rare cases core-shell type polymeric binders, water, pigments and rheology modifiers, as well as other additives.
• the binder must provide a good bond with the fiber of the textile substrate.
• insoluble pigments which have basically no affinity for the fiber, are fixed thereon with binding agents applied according to a desired pattern.
• a good quality pigment print is characterized by its brilliance and high color value relative to the pigment concentration in the paste (printing composition), minimum stiffening in the handle of textile and generally acceptable fastness properties.
• Successful pigment printing systems are based upon three equally important components: pigment dispersions, binders and crosslinking agents, and auxiliary agents (e.g. thickener) giving a required rheology to the printing composition and the final product ( W.C. Miles, Textile Printing, Society of Dyers and Colourist Bradford England, p. 140 (2004 )).
• Crosslinking increases crocking, washing and dry cleaning fastness properties, but detrimentally affects the handle of the fabric.
• an additional crosslinking agent such as urea formaldehyde or melamine formaldehyde condensate, methylolated urethane compounds etc, having at least two reactive groups per molecule are added in the binder system ( V.A. Shenai, Chemistry of Textile Auxiliaries, Sevak Publisher Mumbai, p. 231 (2002 )).
• NMA N-methylolacrylamide
• binders and coatings A primary use of these emulsions is for imparting adequate resistance to water and solvents depending on the performance desired in the final products, such as with nonwoven fabrics and coated papers.
• crosslinking agent 4-6% (w/w) crosslinking agent is used based on total monomer content, to have more resistant printing against water and alkali media.
• Crosslinking of NMA can be achieved by thermal curing or by catalysis with acids or bases. Also formaldehyde release during the crosslinking reactions of (NMA) in the binders can be caused by instability of the crosslinks, during thermal curing or catalysis with acids or bases [Bufkin, 1978].
• EP 0 438 284 A1 discloses acid curing lacquers based on nonaqueous alkyl-urea resin combinations having reduced formaldehyde emissions through use of a compound having an acidic alpha-methylene group such as acetoacetamide.
• various formaldehyde scavengers have been developed in the textile industry including the use of urea, nitrogen containing aromatic heterocyclics and nonaromatic alcohols, e.g. as in EP 0302 289 A1 .
• emulsion polymers are prepared by reacting radically reactive monomers in an aqueous medium that contains an emulsifier and a water-soluble radical initiator.
• the emulsifier include surfactants such as alkylbenzenesulfonates (e.g. sodium dodecylbenzenesulfonate), dialkyl sulfosuccinates (e.g. sodium dodecylsulfosuccinate) and polyoxyethylene alkylphenyl ether sulfate (e.g. sodium polyoxyethylene alkylphenyl ethoxy sulfate).
• water soluble radical initiator examples include persulfates (e.g. ammonium persulfate, sodium persulfate, potassium persulfate) and water soluble hydroperoxide (e.g. hydrogen peroxide, t-butyl hydroperoxide).
• persulfates e.g. ammonium persulfate, sodium persulfate, potassium persulfate
• water soluble hydroperoxide e.g. hydrogen peroxide, t-butyl hydroperoxide
• Preparation of core-shell polymers is generally achieved by stepwise emulsion polymerization, which basically comprises a first step of preparing core particles of latex and a second step of preparing the shell polymer.
• the core particles act as seed particles onto whose surface the shell polymers become preferentially deposited.
• An emulsion polymer contains at least one copolymerized ethylenically unsaturated monomer. At a high temperature above 75°C, ethylenically unsaturated monomer forms reactive radicals if any initiator is present in the reaction media.
• Ethylenically unsaturated monomers include, for example, (meth)acrylic ester monomers including methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethyl acrylate, decyl acrylate, lauryl acrylate, methyl methacrylate, butyl methacrylate, isodecyl methacrylate, lauryl methacrylate, hydroxyethyl (meth)acrylate and hydroxypropyl (meth)acrylate; (meth)acrylamide; (meth)acrylonitrile; styrene and substituted styrenes, butadiene; vinyl acetate, vinyl butyrate and other vinyl esters; and other vinyl monomers such as ethylene, vinyl chloride, vinylidene chloride.
• Calculated glass transition temperature (T g ) of an emulsion polymer is typically from -65°C to 65°C, or alternatively, from -55°C to 20°C.
• T g 's of the co- or terpolymers can be estimated using Fox equation.
• Glass transition temperatures of co- or terpolymers (here, core and shell) can be tuned by mixing and polymerizing of predetermined relative amounts of different monomers (1 to n) having different glass transition temperatures (T g,1 to T g,n ) when they are polymerized to form their homopolymers, said relative amounts being approximately calculated using e.g.
• Primary object of the present invention is to overcome the abovementioned shortcomings of the prior art.
• Another object of the present invention is to provide a binder which reduces the amount of released formaldehyde from pigment printing binder during and after curing on a printed textile substrate, without decreasing the fastness performances; and a pigment printing paste comprising such binder.
• a further object of the present invention is to provide a method for preparation of such binder.
• the present invention proposes a core-shell type binder wherein each of core and shell comprise copolymer or terpolymer of acrylic-based monomers; at least one of the core or the shell comprises a suitable crosslinking agent; core and shell have different glass transition temperatures, and the crosslinking agent content of the binder is less than 4% (w/w) based on the total weight of said monomers.
• the present invention proposes a core-shell type binder for pigment printing.
• Said binder is a multi-layer emulsion particle having a polymeric core component and polymeric shell component which can be employed in coating compositions for pigment printing applications in textile industry.
• each of core and shell comprise copolymer or terpolymer of acrylic-based monomers. At least one of the core or the shell comprises a suitable crosslinking agent.
• the core and shell of the binder according to the present invention have different glass transition temperatures.
• the crosslinking agent content is less than 4% (w/w) based on the total weight of said monomers.
• said copolymer or terpolymer is one or more substance selected from the list consisting of acrylic copolymers such as styrene acrylic copolymer, vinyl acrylic copolymer, copolymer of vinyl acetate with vinyl ester of a branched organic acid having 9 to 11 Carbon atoms (vinyl acetate/VeoVaTM copolymer), terpolymer of vinyl acetate and acrylate with vinyl ester of a branched organic acid having 9 to 11 Carbon atoms (vinyl acetate/acrylic/VeoVaTM terpolymer), vinyl acetate/ethylene copolymer (VAE), vinyl acetate/ethylene/acrylic terpolymer (VAEA), and a styrene/acrylic acid ester copolymer.
• acrylic copolymers such as styrene acrylic copolymer, vinyl acrylic copolymer, copolymer of vinyl acetate with vinyl ester of a branched
• the styrene/acrylic acid ester copolymer is selected from the list consisting of styrene ethyl acrylate copolymer, styrene butyl acrylate copolymer, styrene 2-ethylhexyl acrylate copolymer and styrene cyclohexyl acrylate copolymer. These substances are also highly available and affordable, and they showed suitable performance in laboratory tests.
• the core has a glass transition temperature within the range between -30 and 0°C, preferably within the range between -20°C and -5°C; and the shell has a glass transition temperature within the range between 0°C and 50°C, preferably within the range between 10°C and 30°C.
• mechanical resistance of the binder is enhanced by providing that the shell is rather hard.
• the glass transition temperature of the shell allows film formation under room temperature (20°C) or standard temperature (25°C), in which case the film formation can be achieved without additional heating costs. This is easily achieved when the glass transition temperature of the shell is within the range between 10°C and 20°C.
• the core has a glass transition temperature within the range between 0°C and 50°C, preferably within the range between 10°C and 30°C; and the shell has a glass transition temperature within the range between -30°C and 0°C, preferably within the range between -20°C and -5°C.
• film formation is easily achieved at ambient temperatures even in cold places, for instance at an unheated factory in winter, e.g. under normal temperature (0°C).
• the crosslinking agent content of the core is less than 1% (w/w) based on the total weight of the polymeric material (i.e. based on the total weight of the co- or terpolymerization products of respective monomers) comprised by the core; and the crosslinking agent content of the shell is within the range between 1% and 3% (w/w), preferably within the range between 1.5% and 2.5% (w/w), more preferably within the range between 1.8% and 2.2% (w/w), based on the total weight of the polymeric material (i.e. based on the total weight of the co- or terpolymerization product of respective monomers) comprised by the shell.
• the binder has a core:shell weight ratio within the range between 20:80 and 80:20, more preferably within the range between 20:80 and 60:40, even more preferably within the range between 20:80 and 40:60.
• core:shell weight ratios secure that both core and shell are substantially present without being basically omittable, and the above mentioned advantages of core-shell morphology is significantly observed with these ratios.
• the crosslinking agent is selected from a list consisting of N-methylolacrylamide, diacetone acrylamide, adipic acid dihydrazide, and acetoacetoxy ethylmethacrylate, polyamine.
• a method for obtainment of the binder according to the present invention.
• the method comprises a first emulsion polymerization step for formation of a core from a first pre-emulsion comprising a copolymerizable or terpolymerizable (shortened as co- or terpolymerizable) first mixture of monomers, followed by a second emulsion polymerization step for formation of a shell coated on said core, from a second pre-emulsion different from the first pre-emulsion comprising a copolymerizable or terpolymerizable second mixture of monomers different than said first mixture of monomers; such that the first pre-emulsion and the second pre-emulsion in total comprise less than 4% (w/w) of crosslinking agent based on the total weight of respective monomers; and such that the glass transition temperatures of the copolymerization or terpolymerization products of the first mixture of monomers and the second mixture of monomers are different.
• the method preferably comprises the following steps of:
• the monomers in the first and/or second pre-emulsions are suitable for obtainment of one or more copolymer or terpolymer is one or more substance selected from the list consisting of acrylic copolymers such as styrene acrylic copolymer, vinyl acrylic copolymer, copolymer of vinyl acetate with vinyl ester of a branched organic acid having 9 to 11 Carbon atoms, terpolymer of vinyl acetate and acrylate with vinyl ester of a branched organic acid having 9 to 11 Carbon atoms, vinyl acetate/ethylene copolymer, vinyl acetate/ethylene/acrylic terpolymer, and a styrene/acrylic acid ester copolymer.
• acrylic copolymers such as styrene acrylic copolymer, vinyl acrylic copolymer, copolymer of vinyl acetate with vinyl ester of a branched organic acid having 9 to 11 Carbon atoms
• the styrene/acrylic acid ester copolymer is selected from the list consisting of styrene ethyl acrylate copolymer, styrene butyl acrylate copolymer, styrene 2-ethylhexyl acrylate copolymer and styrene cyclohexyl acrylate copolymer.
• the monomers in the first and/or second pre-emulsions are selected from the list consisting of vinyl acetate (VAc), butyl acrylate (BA), styrene (St), methyl methacrylate (MMA), 2-ethylhexyl acrylate (2-EHA).
• VAc vinyl acetate
• BA butyl acrylate
• St styrene
• MMA methyl methacrylate
• 2-EHA 2-ethylhexyl acrylate
• the radical initiator is preferably tert-butyl hydroperoxide and/or the activator comprises one or more substance selected from the list consisting of sodium metabisulfite, tartaric acid, and ascorbic acid.
• the glass transition temperature of the copolymerization or terpolymerization products of the first mixture of monomers is within the range between -30 and 0°C, preferably within the range between -20°C and -5°C and the glass transition temperature of the copolymerization or terpolymerization products of the second mixture of monomers is within the range between 0°C and 50°C, preferably within the range between 10°C and 30°C.
• the glass transition temperature of the copolymerization or terpolymerization products of the first mixture of monomers is within the range between 0°C and 50°C, preferably within the range between 10°C and 30°C
• the glass transition temperature of the copolymerization or terpolymerization products of the second mixture of monomers is within the range between -30°C and 0°C, preferably within the range between -20°C and -5°C.
• the crosslinking agent content of the first pre-emulsion is less than 1% (w/w) based on the total weight of the monomers comprised by the first mixture of monomers; and the crosslinking agent content of the second pre-emulsion is within the range between 1% and 3%(w/w), preferably within the range between 1.5% and 2.5%(w/w), more preferably within the range between 1.8% and 2.2% (w/w), based on the total weight of the monomers comprised by the second mixture of monomers.
• the first and second mixtures of monomers have a weight ratio within the range between 20:80 and 80:20, preferably within the range between 20:80 and 60:40, more preferably within the range between 20:80 and 40:60 for obtainment of a binder having a core:shell weight ratio mainly within said ranges.
• the first and/or the second pre-emulsions each comprise a different mixture of monomers with pre-calculated weight ratios of said monomers differing between the first and second pre-emulsions for each monomer; wherein the glass transition temperature of co- or terpolymers to be prepared by co- or terpolymerization of said monomers are pre-determined by such pre-calculation using a suitable correlation known in the art e.g. Fox Equation.
• the preferred co-/ or terpolymers to be used in core and/or shell are selected from the list consisting of acrylic copolymers such as styrene acrylic copolymer, vinyl acrylic copolymer, copolymer of vinyl acetate with vinyl ester of a branched organic acid having 9 to 11 Carbon atoms, terpolymer of vinyl acetate and acrylate with vinyl ester of a branched organic acid having 9 to 11 Carbon atoms, vinyl acetate/ethylene copolymer, vinyl acetate/ethylene/acrylic terpolymer, and a styrene/acrylic acid ester copolymer; suitable monomers to obtain said materials are to be used in preparation of the first and/or second pre-emulsions.
• acrylic copolymers such as styrene acrylic copolymer, vinyl acrylic copolymer, copolymer of vinyl acetate with vinyl ester of a branched organic acid having 9 to 11 Carbon atoms
• Suitable monomers for this purpose can be selected by a person skilled in the art of polymerization.
• Examples of such monomers suitable for employing in the first and/or second pre-emulsions include vinyl acetate (VAc), butyl acrylate (BA), styrene (St), methyl methacrylate (MMA), 2-ethylhexyl acrylate (2-EHA), but are not limited thereto and other suitable crosslinkable monomers can also be employed for obtainment of the core and/or shell of the binder according to the present invention.
• Both first and second emulsion polymerization steps are performed in a stirred reactor, and under a reaction temperature ranging between 70°C and 90°C, and more preferably 75°C and 85°C.
• a pre-mixture comprising (preferably de-ionized) water, a pH buffer and a minor amount of emulsifier which is 5-20%, preferably 8%-12% of a total amount of an emulsifier are loaded into the reactor, and heated to the reaction temperature under inert atmosphere.
• the first and second pre-emulsions for use in the method comprising the remaining amount of the emulsifier, which is 80-95%, preferably 88%-92% of the total amount of the emulsifier (e.g. the remaining 90% of the total amount of the emulsifier), and (preferably deionized) water is to be prepared along with a solution of a pre-initiator such as ammonium persulfate (APS).
• APS ammonium persulfate
• a first pre-emulsion and a second pre-emulsion are to be prepared for use in preparation of the core and the shell, with pre-determined total amounts of emulsifier for the first and second pre-emulsions, respectively.
• a minor first amount of a pre-initiator solution e.g. 5% of a total pre-initiator amount to be used throughout the method
• a minor first part of the first pre-emulsion e.g. 5% of a total amount of the first pre-emulsion to be used throughout the method
• remaining second part of the first pre-emulsion is slowly (e.g. in about 1 hour) introduced into the reactor, preferably throughout 45 minutes to 90 minutes.
• core particles start to grow in the reactor.
• Mean particle size of the core particles depends on the duration before the second pre-emulsion is introduced into the reactor. Preferably, said duration is within the range between 10 and 20 minutes, more preferably within the range between 13 and 17 minutes.
• the second pre-emulsion is slowly (e.g. in about 2 hours) introduced into the reactor, preferably throughout 90 minutes to 150 minutes.
• a second amount of the pre-initiator solution which is greater than the minor first amount of the pre-initiator solution (e.g. the remaining 95% of the total amount used throughout the method) is slowly introduced into the reactor, preferably from the beginning of the emulsion polymerization up to the end of the introduction of the second pre-emulsion.
• pre-initiator e.g. APS
• w/w 0.05% and 0.15%
• w/w 0.075% and 0.125%
• a radical initiator e.g. tert-butyl hydroperoxide and an activator e.g. sodium metabisulfite, tartaric acid, ascorbic acid are added into the reactor for scavenging and consuming any unreacted monomers; and the reactor is cooled down to a temperature below 50°C.
• additives such as antifoaming agent, biocide, pH control additives (acidic or basic additives or buffers) can be added into the reactor according to any further requirements of the binder.
• the reaction product is then filtered and thus, a core-shell type binder according to the present invention is obtained.
• a pigment printing paste comprising the binder according to the present invention and a method for preparation thereof are also hereby provided.
• the paste has a viscosity within the range between 20 and 25 Pa ⁇ s, a pH value between 8 and 9.
• the paste preferably comprises 10% to 25% (w/w) of the binder according to the present invention; 1.5% to 2.5%, preferably 1.75% to 2% (w/w) of thickener (preferably a synthetic thickener), 0.05% to 0.15% (w/w) of a pH control additive (e.g. ammonia as a cost effective example), and a complementary amount of water, based on the total weight of the paste.
• a pH control additive e.g. ammonia as a cost effective example
• the method for preparation of a pigment printing paste comprises mixing a binder according to the present invention with a mixture comprising water, a pH control additive and a thickener; wherein the paste preferably comprises 10% to 25% (w/w) of said binder; 1.5% to 2.5% (w/w), more preferably 1.75% to 2% (w/w) of a synthetic thickener, 0.05% to 0.15% (w/w) of a pH control additive which is preferably ammonia, and a complementary amount of water, based on the total weight of the paste.
• Styrene/butyl acrylate copolymer binder comprising a polymeric core and shell with glass transition temperatures of 30°C ( ⁇ 303K) and -20°C ( ⁇ 253K), respectively, was prepared.
• Relevant T g calculations performed using Fox Equation are given below.
• additives here, acrylic acid, methacrylic acid, N-methylol Acrylamide etc. with total ratio in pre-emulsions lower than 4% (w/w) based on the total monomer content
• T g values are compared with relevant target T g values, and accepted if obtained values are within a ⁇ 1K interval from said target values.
• aqueous first pre-emulsion of monomers distributed homogeneously stabilized by emulgators was charged into the reactor and stirred for 20 minutes.
• an aqueous second pre-emulsion along with an initiator was charged into the reactor, at 80-82 °C. Afterwards, post additives mainly used in the relevant technical field were added, and then the reaction mixture (i.e. final emulsion) was cooled down to ambient temperature (around room temperature).
• This final emulsion was filtered and total amount of binder, mean particle size ( ⁇ m), MFFT (minimum film forming temperature, in °C), T g (°C), pH, Brookfield viscosity (Pa ⁇ s), solid content (%) and density (g/cm 3 ) thereof were determined.
• Pigment printing pastes were prepared from thus synthesized binder according the formulation (w/w) given in the below Table 1. Table 1. Formulation used for pigment printing pastes prepared for the Example. Component Weight percentage (based on the total weight of the paste) Binder 16 Thickener 2 Ammonia (25%) 0.5 Defoamer 0.1 Pigment 3 Water (complementary amount) Total 100
• Red and blue pigments were added to provide color to the pigment printing pastes prepared for the experiments.
• Each pigment printing paste comprised 30 grams of pigment per 1000 g of pigment printing paste.
• the pastes were applied onto cotton and polyester fabrics according to Zimmer pigment printing table.
• a 75 mesh template of artificial silk was used in transferring the paste onto fabric in a certain pattern.
• Two different fabrics of 100% cotton and 65% cotton/35% polyester blend were used.
• Printed fabrics were pre-dried at 120°C for 2 minutes and then cured at 150°C for 5 minutes. Then performance of the binder in terms of wet and dry abrasion fastness's, washing resistances, color measurements ( ⁇ E, L, a, b measurements) before and after washing, contour sharpness measurements, paste penetration (%P) and K/S values (color intensity comparisons of average values of spectrophotometric measurement results each obtained from several printed points on the fabric, and from several points on the non-printed back side of the printed fabric), etc., of the binder according to the present invention on the printed fabric was compared with a conventional binder containing 6% (w/w) crosslinking agent (NMA) by weight of the total monomer content in said conventional binder.
• NMA crosslinking agent
• Contour sharpness which serves as a comparative measure for comparing the lateral spread of printing pastes on the printed clothes, was performed visually.

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• Engineering & Computer Science (AREA)
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Citations (6)

• 2015
  • 2015-07-06 EP EP15175437.1A patent/EP3115846A1/de not_active Withdrawn

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