Polyurethane dispersion and ink composition

Abstract

This polyurethane dispersion is obtained by dispersing a polyurethane resin in water. The polyurethane resin is a reaction product of an isocyanate group-terminated prepolymer and a chain extender. The isocyanate group-terminated prepolymer is a reaction product of a polyisocyanate component and a polyol component that includes a macropolyol and a hydrophilic group-containing active hydrogen compound. The chain extender includes a trifunctional amine. The polyurethane resin has an acid value of 6.5 to 15.5 mgKOH / g inclusive. The total urea group concentration and urethane group concentration in the polyurethane resin is 20.0% or less. The weight-average molecular weight of the polyurethane resin is 50,000 or more.

Description

Polyurethane dispersion and ink composition

[0001] The present invention relates to polyurethane dispersions and ink compositions.

[0002] It is known that ink jet printing is performed on fabric by ejecting droplets of an ink composition from a nozzle using an ink jet method. The ink composition contains, for example, a colorant and a resin in which the colorant is dispersed.

[0003] As such an ink composition, a water-based inkjet ink containing a pigment (coloring material) and a water-soluble urethane resin (resin) having a weight-average molecular weight of 12,000 or more and 40,000 or less has been proposed (see, for example, Patent Document 1 below).

[0004] Japanese Patent Application Laid-Open No. 2022-093959

[0005] On the other hand, the water-soluble urethane resin of Patent Document 1 has a small weight-average molecular weight, which causes a problem of reduced fastness to friction and washing (hereinafter referred to as fastness) when used to print fabrics. This reduced fastness can lead to discoloration of the printed area or color transfer to white fabrics.

[0006] In order to improve fastness, increasing the weight-average molecular weight of the water-soluble urethane resin has been considered; however, increasing the weight-average molecular weight of the water-soluble urethane resin tends to reduce the mechanical stability of the polyurethane dispersion (particles tend to coalesce and form aggregates due to shear forces during mixing, stirring, and transport). In other words, fastness and mechanical stability are in a trade-off relationship. In addition, in order to improve texture, decreasing the acid value, urethane group concentration, and urea group concentration of the polyurethane resin has been considered; however, decreasing the acid value, urethane group concentration, and urea group concentration of the polyurethane resin tends to reduce the mechanical stability. In other words, texture and mechanical stability are also in a trade-off relationship.

[0007] The present invention provides a polyurethane dispersion that has excellent mechanical stability, and when used to print fabrics, has excellent texture and fastness, and also provides an ink composition containing the polyurethane dispersion.

[0008] The present invention [1] is a polyurethane dispersion in which a polyurethane resin is dispersed in water, wherein the polyurethane resin is a reaction product of an isocyanate-terminated prepolymer and a chain extender, the isocyanate-terminated prepolymer is a reaction product of a polyisocyanate component and a polyol component containing a macropolyol and a hydrophilic-group-containing active hydrogen compound, the chain extender contains a trifunctional amine, the acid value of the polyurethane resin is 6.5 mgKOH / g or more and 15.5 mgKOH / g or less, the sum of the urethane group concentration and the urea group concentration of the polyurethane resin is 20.0 mass% or less, and the weight-average molecular weight of the polyurethane resin is 50,000 or more.

[0009] The present invention [2] includes the polyurethane dispersion according to the above [1], in which the chain extender contains other amines, the other amines being monofunctional amines and difunctional amines, and the amine equivalent ratio of the trifunctional amine to the other amines is 0.17 or more and 5.67 or less.

[0010] The present invention [3] includes the polyurethane dispersion according to the above [1] or [2], in which the weight-average molecular weight of the polyurethane resin is 200,000 or more.

[0011] The present invention [4] includes an ink composition containing the polyurethane dispersion according to any one of the above [1] to [3].

[0012] In the polyurethane dispersion of the present invention, the chain extender contains a trifunctional amine, which can improve the mechanical stability.

[0013] In addition, in this polyurethane dispersion, the acid value of the polyurethane resin is 6.5 mgKOH / g or more, which improves the mechanical stability.

[0014] In this polyurethane dispersion, the polyurethane resin has an acid value of 15.5 mgKOH / g or less, a weight-average molecular weight of 50,000 or more, and a total of a urethane group concentration and a urea group concentration of 20.0 mass% or less, thereby improving fastness and texture when used for printing fabrics.

[0015] The ink composition of the present invention contains the polyurethane dispersion of the present invention, and therefore it is possible to produce printed textiles that are excellent in mechanical stability, fastness, and texture.

[0016] The polyurethane dispersion is prepared by dispersing a polyurethane resin in water.

[0017] The polyurethane resin is a reaction product of an isocyanate-terminated prepolymer and a chain extender.

[0018] <Isocyanate Group-Terminated Prepolymer> The isocyanate group-terminated prepolymer is a reaction product of a polyisocyanate component and a polyol component containing a macropolyol and a hydrophilic group-containing active hydrogen compound.

[0019] [Polyisocyanate Component] The polyisocyanate component includes a polyisocyanate and / or a derivative of a polyisocyanate.

[0020] (Polyisocyanate) Examples of polyisocyanates include alicyclic polyisocyanates, aliphatic polyisocyanates, aromatic polyisocyanates, and araliphatic polyisocyanates.

[0021] Examples of alicyclic polyisocyanates include alicyclic diisocyanates, such as 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate, IPDI), 4,4'-, 2,4'-, or 2,2'-methylenebis(cyclohexyl isocyanate), or mixtures thereof (H １２MDI), 1,3- or 1,4-bis(isocyanatomethyl)cyclohexane or a mixture thereof (H ６ Examples of the alicyclic polyisocyanate include bis(isocyanatomethyl)norbornane (NBDI), 1,3-cyclopentene diisocyanate, 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, methyl-2,4-cyclohexane diisocyanate, and methyl-2,6-cyclohexane diisocyanate. １２ MDI and H ６ XDI is an example.

[0022] Examples of aliphatic polyisocyanates include aliphatic diisocyanates. Examples of aliphatic diisocyanates include 1,6-hexamethylene diisocyanate (1,6-HDI), 1,5-pentamethylene diisocyanate (1,5-PDI), tetramethylene diisocyanate, trimethylene diisocyanate, 1,2-, 2,3-, or 1,3-butylene diisocyanate, and 2,4,4- or 2,2,4-trimethylhexamethylene diisocyanate. Preferred aliphatic polyisocyanates include 1,6-HDI and 1,5-PDI.

[0023] Examples of aromatic polyisocyanates include aromatic diisocyanates, such as 4,4'-, 2,4'-, or 2,2'-diphenylmethane diisocyanate or a mixture thereof (MDI), 2,4- or 2,6-tolylene diisocyanate or a mixture thereof (TDI), o-tolidine diisocyanate, 1,5-naphthalene diisocyanate (NDI), m- or p-phenylene diisocyanate or a mixture thereof, 4,4'-diphenyl diisocyanate, and 4,4'-diphenyl ether diisocyanate.

[0024] Examples of araliphatic polyisocyanates include araliphatic diisocyanates. Examples of araliphatic diisocyanates include xylylene diisocyanate (1,2-, 1,3-, or 1,4-xylylene diisocyanate or a mixture thereof) (XDI), 1,3- or 1,4-tetramethylxylylene diisocyanate or a mixture thereof (TMXDI), and ω,ω'-diisocyanato-1,4-diethylbenzene. Preferred araliphatic polyisocyanates include XDI.

[0025] The polyisocyanate is preferably an alicyclic polyisocyanate, an aliphatic polyisocyanate, or an araliphatic polyisocyanate, and more preferably an alicyclic polyisocyanate from the viewpoint of improving filterability.

[0026] The polyisocyanates can be used alone or in combination of two or more kinds.

[0027] (Polyisocyanate Derivatives) Examples of polyisocyanate derivatives include the above-mentioned polyisocyanate polymers, allophanate derivatives, polyol derivatives, biuret derivatives, urea derivatives, oxadiazinetrione derivatives, carbodiimide derivatives, uretdione derivatives, and uretonimine derivatives.

[0028] The polyisocyanate derivatives can be used alone or in combination of two or more kinds.

[0029] The polyisocyanate component preferably does not contain a derivative of polyisocyanate but contains a polyisocyanate, and more preferably contains an alicyclic polyisocyanate.

[0030] [Polyol Component] The polyol component contains a macropolyol and a hydrophilic group-containing active hydrogen compound.

[0031] (Macropolyol) The macropolyol is a compound having two or more hydroxyl groups at the molecular terminals and a number average molecular weight of 400 to 10,000, preferably 500 to 5,000.

[0032] The average functionality of the macropolyol is, for example, 2 or more, and for example, 3 or less, and preferably 2.

[0033] Examples of the macropolyol include polycarbonate polyol, polyether polyol, polyester polyol, polyurethane polyol, epoxy polyol, polyolefin polyol, acrylic polyol, silicone polyol, fluorine polyol, and vinyl monomer-modified polyol. Preferred examples of the macropolyol include polycarbonate polyol, polyether polyol, and polyester polyol.

[0034] Examples of polycarbonate polyols include polycarbonate diols, such as a ring-opening polymer of ethylene carbonate using a low-molecular-weight polyol (preferably a dihydric alcohol) as an initiator, as described below, and polycarbonate diols obtained by copolymerizing a ring-opening polymer with a dihydric alcohol (e.g., 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, and 1,6-hexanediol).

[0035] Examples of polyether polyols include polyoxyalkylene (having 2 to 3 carbon atoms) polyols and polytetramethylene ether polyols.

[0036] Examples of polyoxyalkylene (carbon number: 2 to 3) polyols include addition polymers of alkylene oxides having 2 to 3 carbon atoms using, as an initiator, low-molecular-weight polyols described below and known low-molecular-weight polyamines.

[0037] Examples of alkylene oxides having 2 to 3 carbon atoms include propylene oxide and ethylene oxide. These alkylene oxides can be used alone or in combination of two or more.

[0038] Specific examples of polyoxyalkylene (carbon number 2 to 3) polyols include polyoxyethylene glycol, polyoxypropylene glycol, and random and / or block copolymers of propylene oxide and ethylene oxide.

[0039] Furthermore, the polyoxyalkylene (carbon number 2 to 3) polyol also includes polytrimethylene ether glycol.

[0040] An example of polytrimethylene ether glycol is a glycol obtained by polycondensation reaction of 1,3-propanediol derived from plant components.

[0041] Examples of polytetramethylene ether polyols include ring-opening polymers (polytetramethylene ether glycol (crystalline (solid at 25°C))) obtained by cationic polymerization of tetrahydrofuran, and amorphous (non-crystalline (liquid at 25°C)) polytetramethylene ether glycols obtained by copolymerizing polymerization units of tetrahydrofuran or the like with alkyl-substituted tetrahydrofuran or the above-mentioned dihydric alcohols.

[0042] As the polyether polyol, preferably, polytetramethylene ether polyol is used, and more preferably, polytetramethylene ether glycol is used.

[0043] Examples of polyester polyols include polycondensates obtained by reacting a low-molecular-weight polyol (described below) with a polybasic acid under known conditions.

[0044] The low molecular weight polyol is preferably an alkanediol having 2 to 6 carbon atoms, and more preferably 3-methyl-1,5-pentanediol.

[0045] Examples of polybasic acids include aromatic dibasic acids, alicyclic dibasic acids, and aliphatic dibasic acids.

[0046] Examples of aromatic dibasic acids include aromatic carboxylic acids. Examples of aromatic carboxylic acids include phthalic acid (orthophthalic acid, isophthalic acid, terephthalic acid) and trimellitic acid. Examples of aromatic dibasic acids include phthalic acid, preferably phthalic acid. Examples of aromatic dibasic acids include terephthalic acid, more preferably terephthalic acid.

[0047] Examples of alicyclic dibasic acids include alicyclic carboxylic acids, such as hexahydroxybenzoic acid and 1,2-hexahydrophthalic acid.

[0048] Examples of the aliphatic dibasic acid include aliphatic carboxylic acids, such as oxalic acid, malonic acid, succinic acid, methylsuccinic acid, 2,2-dimethylsuccinic acid, 2,3-dimethylsuccinic acid, hexylsuccinic acid, glutaric acid, 2-methylglutaric acid, 3-methylglutaric acid, 2,2-dimethylglutaric acid, 3,3-dimethylsuccinic acid, adipic acid, pimelic acid, suberic acid, azelaic acid, and sebacic acid, and preferably adipic acid and sebacic acid.

[0049] The polybasic acid is preferably an aromatic dibasic acid.

[0050] A preferred example of such a polyester polyol is a polycondensation product of 3-methyl-1,5-pentanediol and terephthalic acid.

[0051] As the macropolyol, preferably, polycarbonate polyol is used.

[0052] The macropolyols can be used alone or in combination of two or more kinds.

[0053] The blending ratio of the macropolyol relative to 100 parts by mass of the total amount of the polyol components is, for example, 80 to 99 parts by mass, or preferably 90 to 98 parts by mass.

[0054] (Hydrophilic Group-Containing Active Hydrogen Compound) The hydrophilic group-containing active hydrogen compound is a compound containing a hydrophilic group and two or more active hydrogen groups. Examples of the active hydrogen groups include a hydroxyl group and an amino group.

[0055] Examples of the hydrophilic group include a nonionic group and an ionic group. More specific examples of the hydrophilic group-containing active hydrogen compound include an active hydrogen group-containing compound containing a nonionic group and an active hydrogen group-containing compound containing an ionic group.

[0056] The active hydrogen group-containing compound containing a nonionic group is a compound having one or more nonionic groups and two or more active hydrogen groups. Examples of the nonionic group include a polyoxyethylene group. Examples of the active hydrogen group-containing compound containing a nonionic group include polyoxyethylene glycol, one-end-blocked polyoxyethylene glycol, and polyols containing polyoxyethylene side chains.

[0057] Examples of active hydrogen group-containing compounds containing an ionic group include active hydrogen group-containing compounds containing an anionic group and active hydrogen group-containing compounds containing a cationic group.

[0058] The active hydrogen group-containing compound containing anionic group is a compound that has one or more anionic groups and two or more active hydrogen groups.The anionic group can be exemplified by a carboxy group (carboxylic acid group) and a sulfo group (sulfonic acid group), and preferably by a carboxy group.In addition, in the active hydrogen group-containing compound containing anionic group, the active hydrogen group can be exemplified by a hydroxyl group and an amino group, and preferably by a hydroxyl group.That is, the active hydrogen group-containing compound containing anionic group can be preferably an organic compound that has one carboxyl group and two hydroxyl groups.

[0059] An example of an organic compound having one carboxy group and two hydroxyl groups is a carboxy group-containing polyol. An example of a carboxy group-containing polyol is a dihydroxyalkanoic acid. Examples of dihydroxyalkanoic acids include 2,2-dimethylolacetic acid, 2,2-dimethylollactic acid, 2,2-dimethylolpropionic acid (also known as dimethylolpropionic acid), 2,2-dimethylolbutanoic acid, 2,2-dimethylolbutyric acid, and 2,2-dimethylolvaleric acid. A preferred example of an organic compound having one carboxy group and two hydroxyl groups is 2,2-dimethylolpropionic acid.

[0060] The active hydrogen group-containing compound containing cationic group is a compound that has one or more cationic groups and two or more active hydrogen groups.The cationic group can be, for example, a tertiary amino group (a tertiary amine that can form a tertiary ammonium salt).In addition, in the active hydrogen group-containing compound containing cationic group, the active hydrogen group can be, for example, a hydroxyl group and an amino group, and preferably a hydroxyl group.That is, the active hydrogen group-containing compound containing cationic group can be, preferably, an organic compound that has one tertiary amino group and two hydroxyl groups.

[0061] Examples of organic compounds having one tertiary amino group and two hydroxyl groups include N-alkyldialkanolamines, such as N-methyldiethanolamine, N-propyldiethanolamine, N-butyldiethanolamine, and N-methyldipropanolamine.

[0062] The hydrophilic group-containing active hydrogen compound is preferably an active hydrogen group-containing compound containing an ionic group, and more preferably an active hydrogen group-containing compound containing an anionic group, from the viewpoint of adjusting the acid value of the polyurethane resin described below to a predetermined range.

[0063] The hydrophilic group-containing active hydrogen compounds can be used alone or in combination of two or more kinds.

[0064] The blending ratio of the hydrophilic group-containing active hydrogen compound is, for example, 1 to 20 parts by mass, or preferably 2 to 10 parts by mass, per 100 parts by mass of the total amount of the polyol components.

[0065] In particular, when the hydrophilic group-containing active hydrogen compound is an active hydrogen group-containing compound containing an anionic group (preferably a carboxy group), by setting the blending ratio within the above range, the acid value of the polyurethane resin described below can be set within a predetermined range.

[0066] (Low Molecular Weight Polyol) The polyol component may also contain a low molecular weight polyol (a low molecular weight polyol excluding hydrophilic group-containing active hydrogen compounds) as an optional component.

[0067] The low-molecular-weight polyol is a compound having a number-average molecular weight of 40 or more but less than 400, preferably 40 or more but less than 300.

[0068] The number of functional groups of the low molecular weight polyol is not particularly limited, but is preferably 2.

[0069] Examples of low molecular weight polyols include diols having 2 to 6 carbon atoms and other low molecular weight polyols (excluding diols having 2 to 6 carbon atoms).

[0070] The diol having 2 to 6 carbon atoms has a number average molecular weight of 40 or more but less than 400, preferably 40 or more but less than 300, and is a compound having 2 to 6 carbon atoms and two hydroxyl groups. Examples of the diol include an alkanediol having 2 to 6 carbon atoms (an alkylene glycol having 2 to 6 carbon atoms), an etherdiol having 2 to 6 carbon atoms, and an alkenediol having 2 to 6 carbon atoms.

[0071] Examples of alkanediols having 2 to 6 carbon atoms include ethylene glycol, propylene glycol (1,2- or 1,3-propanediol or a mixture thereof), butylene glycol (1,2-, 1,3-, or 1,4-butanediol or a mixture thereof), 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, and 1,3- or 1,4-cyclohexanediol.

[0072] Examples of the ether diol having 2 to 6 carbon atoms include diethylene glycol, triethylene glycol, and dipropylene glycol, and preferably triethylene glycol.

[0073] An example of the alkenediol having 2 to 6 carbon atoms is 1,4-dihydroxy-2-butene.

[0074] The other low-molecular-weight polyols are compounds having a number-average molecular weight of 40 or more but less than 400, preferably 40 or more but less than 300, and having two or more hydroxyl groups in one molecule, and examples thereof include diols (dihydric alcohols) having 7 or more carbon atoms and low-molecular-weight polyols having 3 or more hydric atoms.

[0075] The diol (dihydric alcohol) having 7 or more carbon atoms is a compound having a number average molecular weight of 40 or more but less than 400, preferably 40 or more but less than 300, and having 7 or more carbon atoms and two hydroxyl groups per molecule. Examples of such compounds include alkane-1,2-diols having 7 to 20 carbon atoms, 2,6-dimethyl-1-octene-3,8-diol, 1,3- or 1,4-cyclohexanedimethanol, and mixtures thereof, hydrogenated bisphenol A, and bisphenol A.

[0076] Examples of diols (dihydric alcohols) having 7 or more carbon atoms include dihydric polyalkylene oxides having a number-average molecular weight of less than 400, preferably 300 or less. Such polyalkylene oxides can be obtained, for example, by addition reaction of alkylene oxides such as ethylene oxide and / or propylene oxide with the above-mentioned dihydric alcohols as an initiator, to give polyethylene glycols (polyoxyethylene ether glycols), polypropylene glycols (polyoxypropylene ether glycols), polyethylenepolypropylene glycols (random or block copolymers), etc. Further examples include polytetramethylene ether glycols having a number-average molecular weight of less than 400, preferably 300 or less, obtained by ring-opening polymerization of tetrahydrofuran, for example.

[0077] The trihydric or higher low-molecular-weight polyol has a number-average molecular weight of 40 or more but less than 400, preferably 40 or more but less than 300, and is a compound having three or more hydroxyl groups per molecule. Examples of the trihydric alcohol include trihydric alcohol (low-molecular-weight triol), tetrahydric alcohol, pentahydric alcohol, hexahydric alcohol, heptahydric alcohol, and octahydric alcohol. Examples of the trihydric alcohol include glycerin, 2-methyl-2-hydroxymethyl-1,3-propanediol, 2,4-dihydroxy-3-hydroxymethylpentane, 1,2,6-hexanetriol, trimethylolpropane, and 2,2-bis(hydroxymethyl)-3-butanol. Examples of the tetrahydric alcohol include tetramethylolmethane (pentaerythritol) and diglycerin. Examples of the pentahydric alcohol include xylitol. Examples of hexahydric alcohols include sorbitol, mannitol, allitol, iditol, dulcitol, altritol, inositol, and dipentaerythritol. Examples of heptahydric alcohols include perseitol. Examples of octahydric alcohols include sucrose.

[0078] Examples of the trivalent or higher low-molecular-weight polyol also include trivalent or higher polyalkylene oxides having a number average molecular weight of 40 or more but less than 400, preferably 40 or more and 300 or less. Such polyalkylene oxides can be obtained as polyethylene polyols, polypropylene polyols, and polyethylene-polypropylene polyols (random or block copolymers) by addition reaction of alkylene oxides such as ethylene oxide and / or propylene oxide with the above-mentioned trivalent or higher low-molecular-weight polyols or known polyamines as initiators.

[0079] The low molecular weight polyols can be used alone or in combination of two or more kinds.

[0080] The blending ratio of the low-molecular-weight polyol is, for example, 1 to 15 parts by mass with respect to 100 parts by mass of the total amount of the polyol components.

[0081] The polyol component preferably does not contain a low-molecular-weight polyol, and is composed of a macropolyol and a hydrophilic group-containing active hydrogen compound.

[0082] [Preparation of Isocyanate-Terminated Prepolymer] The isocyanate-terminated prepolymer is obtained by reacting a polyisocyanate component with a polyol component.

[0083] As a method for reacting the polyisocyanate component and the polyol component, a known polymerization method (e.g., bulk polymerization or solution polymerization) is selected, and preferably, solution polymerization is selected from the viewpoint of easier adjustment of reactivity and viscosity.

[0084] In solution polymerization, for example, the above components are mixed in an organic solvent (solvent) under a nitrogen atmosphere and reacted.

[0085] In this reaction, the equivalent ratio of isocyanate groups in the polyisocyanate component to active hydrogen groups (hydroxyl groups and / or amino groups) in the polyol component (isocyanate groups / active hydrogen groups) exceeds 1, for example, 1.2 or more, preferably 1.3 or more, and for example, 3.0 or less, preferably 2.5 or less. In such a case, the terminal functional group of the resulting reaction product is an isocyanate group. In other words, an isocyanate-terminated prepolymer is obtained.

[0086] As for reaction conditions, the reaction temperature is, for example, 20° C. to 100° C., preferably 40° C. to 90° C. The reaction time is 1 hour to 20 hours.

[0087] Examples of the organic solvent include those which are inert to isocyanate groups and highly hydrophilic, such as acetone, methyl ethyl ketone, ethyl acetate, tetrahydrofuran, acetonitrile, and N-methylpyrrolidone. Acetonitrile is preferred.

[0088] In the polymerization, a reaction catalyst (for example, an amine-based, tin-based, or lead-based catalyst) may be added as needed.

[0089] In the above reaction, unreacted polyisocyanate components and / or unreacted polyol components can be removed by known methods such as distillation or extraction.

[0090] This produces an isocyanate-terminated prepolymer, which is a reaction product of the polyisocyanate component and the polyol component.

[0091] When the polyisocyanate component and the polyol component are reacted by solution polymerization, the isocyanate-terminated prepolymer is obtained as a reaction liquid containing the isocyanate-terminated prepolymer and an organic solvent.

[0092] The isocyanate-terminated prepolymer is a polyurethane prepolymer having at least one (preferably multiple, more preferably two) free isocyanate group at its molecular end, and the isocyanate group content (isocyanate group content calculated as solid content excluding solvent, i.e., isocyanate group concentration) is, for example, 1.2 to 5.0 mass%, preferably 1.3 to 3.0 mass%, more preferably 1.5 to 2.0 mass%.

[0093] Furthermore, when the reaction product contains an ionic group, it is preferable to neutralize it by adding a neutralizing agent to form a salt of the ionic group.

[0094] As the neutralizing agent, when the ionic group is an anionic group, a conventional base (e.g., triethylamine, trimethylamine, preferably triethylamine) is used, and when the ionic group is a cationic group, a conventional acid (e.g., acetic acid) is used.

[0095] In particular, when the ionic group is an anionic group (preferably a carboxy group), the neutralizing agent is added in an amount of 0.6 to 1.2 equivalents, preferably 0.8 to 1.1 equivalents, per equivalent of the anionic group.

[0096] <Chain extender> The chain extender contains a trifunctional amine. When the chain extender contains a trifunctional amine, mechanical stability can be improved.

[0097] The trifunctional amine has a primary amino group and / or a secondary amino group, and has three primary amino groups and three secondary amino groups in total. Note that the number of tertiary amino groups in the trifunctional amine is not limited.

[0098] Examples of trifunctional amines include diethylenetriamine and tris(2-aminoethyl)amine.

[0099] As the trifunctional amine, from the viewpoint of suppressing shrinkage during drying, preferably, diethylenetriamine is used.

[0100] The trifunctional amines can be used alone or in combination of two or more kinds.

[0101] The chain extender preferably contains another amine from the viewpoint of suppressing shrinkage during drying.

[0102] Other amines include monofunctional amines and difunctional amines. If the chain extender contains such other amines, shrinkage during drying can be suppressed.

[0103] A monofunctional amine has one primary amino group or one secondary amino group, and the number of tertiary amino groups in a monofunctional amine is not limited.

[0104] Examples of monofunctional amines include alkylamines and dialkylamines. Examples of alkylamines include 2-ethylhexylamine and cyclohexylamine. Examples of dialkylamines include diethylamine, dipropylamine, and dibutylamine.

[0105] The monofunctional amine is preferably a dialkylamine, and the monoamine is more preferably diethylamine.

[0106] The bifunctional amine has a primary amino group and / or a secondary amino group, i.e., two primary amino groups and two secondary amino groups in total. Note that the number of tertiary amino groups in the bifunctional amine is not limited.

[0107] Examples of bifunctional amines include aromatic diamines, araliphatic diamines, alicyclic diamines, aliphatic diamines, bifunctional amino alcohols, polyoxyethylene group-containing diamines, alkoxysilyl compounds having a primary amino group and a secondary amino group, and hydrazine or derivatives thereof.

[0108] Examples of aromatic diamines include 4,4'-diphenylmethanediamine and tolylenediamine.

[0109] The araliphatic diamine may, for example, be 1,3- or 1,4-xylylenediamine or a mixture thereof.

[0110] Examples of alicyclic diamines include 3-aminomethyl-3,5,5-trimethylcyclohexylamine (also known as isophoronediamine), 4,4'-dicyclohexylmethanediamine, 2,5(2,6)-bis(aminomethyl)bicyclo[2.2.1]heptane, 1,4-cyclohexanediamine, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, bis-(4-aminocyclohexyl)methane, diaminocyclohexane, 3,9-bis(3-aminopropyl)-2,4,8,10-tetraoxaspiro[5,5]undecane, 1,3- and 1,4-bis(aminomethyl)cyclohexane, and mixtures thereof.

[0111] Examples of the aliphatic diamine include 1,2-ethylenediamine, propylenediamine, 1,3-propanediamine, 1,4-butanediamine, 1,5-pentanediamine, and 1,6-hexamethylenediamine. Of the aliphatic diamines, 1,2-ethylenediamine is preferred.

[0112] Examples of bifunctional amino alcohols include 2-(2-aminoethylamino)ethanol (also known as N-(2-aminoethyl)ethanolamine) and 2-((2-aminoethyl)amino)-1-methylpropanol (also known as N-(2-aminoethyl)isopropanolamine).

[0113] Examples of polyoxyethylene group-containing diamines include polyoxyalkylene ether diamines such as polyoxyethylene ether diamine, etc. More specific examples include PEG#1000 diamine manufactured by NOF Corporation, and Jeffamine ED-2003, EDR-148, and XTJ-512 manufactured by Huntsman.

[0114] Examples of alkoxysilyl compounds having a primary amino group and a secondary amino group include N-β(aminoethyl)γ-aminopropyltrimethoxysilane (also known as N-2-(aminoethyl)-3-aminopropyltrimethoxysilane), N-β(aminoethyl)γ-aminopropyltriethoxysilane (also known as N-2-(aminoethyl)-3-aminopropyltriethoxysilane), N-β(aminoethyl)γ-aminopropylmethyldimethoxysilane (also known as N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane), and N-β(aminoethyl)γ-aminopropylmethyldiethoxysilane (also known as N-2-(aminoethyl)-3-aminopropylmethyldiethoxysilane).

[0115] Examples of hydrazine or its derivatives include hydrazine (including hydrazine monohydrate), succinic acid dihydrazide, and adipic acid dihydrazide.Preferably, hydrazine monohydrate is used as the hydrazine or its derivatives.

[0116] As the bifunctional amine, preferably, an aliphatic diamine, and hydrazine or a derivative thereof are used. As the bifunctional amine, preferably, an aliphatic diamine is used from the viewpoint of improving mechanical stability.

[0117] The other amine preferably includes a difunctional amine. The other amine preferably does not include a monofunctional amine but includes a difunctional amine.

[0118] When the other amine does not contain a monofunctional amine but contains a difunctional amine, the tackiness (stickiness) is improved, resulting in a good feel to the touch. In addition, the weight average molecular weight of the polyurethane resin described below can be increased.

[0119] In the chain extender, the amine equivalent ratio of the trifunctional amine to the other amine is, for example, 0.10 to 10.0, preferably 0.17 to 5.67, more preferably 0.5 to 5.0, even more preferably 1.0 to 4.5, particularly preferably 1.2 to 3.5, and most preferably 1.4 to 2.0.

[0120] In detail, the above-mentioned equivalent ratio is, for example, 0.10 or more, and from the viewpoint of improving mechanical stability, preferably 0.17 or more, more preferably 0.5 or more, even more preferably 1.0 or more, particularly preferably 1.2 or more, and most preferably 1.4 or more; and from the viewpoint of suppressing shrinkage during drying, for example, 10.0 or less, preferably 5.67, more preferably 5.0 or less, even more preferably 4.5 or less, particularly preferably 3.5 or less, and most preferably 2.0 or less.

[0121] <Preparation of Polyurethane Resin> The polyurethane resin is obtained by reacting an isocyanate group-terminated prepolymer with a chain extender.

[0122] Specifically, an isocyanate-terminated prepolymer and a chain extender are reacted in water, for example, to obtain a polyurethane resin (polyurethane dispersion).

[0123] To react the isocyanate group-terminated prepolymer with the chain extender in water, for example, the isocyanate group-terminated prepolymer is first added to water to disperse the isocyanate group-terminated prepolymer in water, and then a chain extender is added thereto to extend the chain of the isocyanate group-terminated prepolymer with the chain extender.

[0124] To disperse the isocyanate-terminated prepolymer in water, 50 to 1,000 parts by mass of water (sometimes referred to as water dispersion water) is added to 100 parts by mass of the isocyanate-terminated prepolymer while stirring the water.

[0125] Thereafter, the chain extender is added dropwise to the water in which the isocyanate group-terminated prepolymer has been dispersed, while stirring, so that the equivalent ratio of the active hydrogen groups (amino groups and hydroxyl groups) of the chain extender to the isocyanate groups of the isocyanate group-terminated prepolymer (active hydrogen groups / isocyanate groups) is, for example, 0.8 or more and 1.2 or less.

[0126] Conversely to the above, water can be added to the isocyanate group-terminated prepolymer to disperse the isocyanate group-terminated prepolymer in water, and then a chain extender can be added thereto to extend the chains of the isocyanate group-terminated prepolymer with the chain extender.

[0127] In this method, the organic solvent and water can be removed as needed, and further, water can be added to adjust the solid content concentration.

[0128] This allows the chains of the isocyanate-terminated prepolymer to be extended by the chain extender, thereby obtaining a polyurethane resin prepared as an aqueous dispersion (polyurethane dispersion).

[0129] The acid value of the polyurethane resin is 6.5 mgKOH / g to 15.5 mgKOH / g, preferably 7.0 mgKOH / g to 14.0 mgKOH / g, more preferably 8.0 mgKOH / g to 12.0 mgKOH / g, even more preferably 8.5 mgKOH / g to 11.0 mgKOH / g, and particularly preferably 9.0 mgKOH / g to 10.0 mgKOH / g.

[0130] Specifically, the acid value of the polyurethane resin is 6.5 mgKOH / g or more, preferably 7.0 mgKOH / g or more, more preferably 8.0 mgKOH / g or more, even more preferably 8.5 mgKOH / g or more, particularly preferably 9.0 mgKOH / g or more, and 15.5 mgKOH / g or less, preferably 14.0 mgKOH / g or less, more preferably 12.0 mgKOH / g or less, even more preferably 11.0 mgKOH / g or less, particularly preferably 10.0 mgKOH / g or less.

[0131] When the acid value of the polyurethane resin is equal to or higher than the lower limit, the mechanical stability and filterability can be improved.

[0132] On the other hand, if the acid value of the polyurethane resin is less than the lower limit, the mechanical stability and filterability will be reduced.

[0133] Furthermore, if the acid value of the polyurethane resin is equal to or less than the above upper limit, the texture is excellent when the fabric is printed.

[0134] On the other hand, if the acid value of the polyurethane resin exceeds the upper limit, the feel deteriorates.

[0135] The acid value can be adjusted to fall within the above range, for example, by adjusting the blending ratio of the active hydrogen group-containing compound that contains an anionic group (preferably a carboxy group).

[0136] The acid value can be calculated from the ratio of the components. The acid value can also be measured by a method according to JIS K 0070 (1992). The acid value can also be calculated by the acid value of the hydrolysis product of the polyurethane resin by alkaline hydrolysis. １ It can also be measured by H-NMR.

[0137] The total concentration of urethane groups and urea groups in the polyurethane resin is 20.0% by mass or less, preferably 15.5% by mass or less, more preferably 15.0% by mass or less, even more preferably 12.0% by mass or less, particularly preferably 11.0% by mass or less, and most preferably 10.0% by mass or less.

[0138] If the total concentration of the urethane group and the urea group in the polyurethane resin is equal to or less than the above upper limit, the feel can be improved when the fabric is printed.

[0139] On the other hand, if the total concentration of the urethane group and the urea group in the polyurethane resin exceeds the upper limit, the feel deteriorates.

[0140] Furthermore, from the viewpoint of improving mechanical stability, the total concentration of urethane groups and urea groups in the polyurethane resin is, for example, 5.0 mass% or more, preferably 7.0 mass% or more, more preferably 8.0 mass% or more, and even more preferably 9.0 mass% or more.

[0141] The total of the urethane group concentration and the urea group concentration can be calculated from the charge ratio of the raw material components. １ It can also be measured by H-NMR.

[0142] The weight average molecular weight of the polyurethane resin is 50,000 or more, preferably 100,000 or more, more preferably 150,000 or more, even more preferably 180,000 or more, and particularly preferably 200,000 or more from the viewpoint of further improving robustness.

[0143] When the weight average molecular weight of the polyurethane resin is at least the above lower limit, fastness can be improved when printing fabrics.

[0144] On the other hand, if the weight average molecular weight of the polyurethane resin is less than the above lower limit, fastness decreases when a fabric is printed.

[0145] The weight average molecular weight of the polyurethane resin is, for example, 500,000 or less, or preferably 400,000 or less.

[0146] The weight-average molecular weight of the polyurethane resin is measured by gel permeation chromatography (GPC) and is calculated in terms of polystyrene. Specifically, it can be measured under the following conditions using dimethylacetamide dissolved in lithium bromide at a concentration of 0.86 g / L as the developing solvent. {Conditions} Apparatus: EcoSEC HLC-8320GPC (manufactured by Tosoh Corporation) Column: Two TSKgel α-M columns (manufactured by Tosoh Corporation) Flow rate: 0.6 ml / min Sample: Prepared by dissolving in the developing solvent at a concentration of 10 mg / mL Column temperature: 40°C Injection volume: 100 μl Detector: Differential refractometer Sampling time interval: 0.015 seconds

[0147] The solids concentration of the polyurethane dispersion is, for example, 10% by mass to 50% by mass, or preferably 20% by mass to 40% by mass.

[0148] <Use of Polyurethane Dispersion> The polyurethane dispersion is suitably used in the ink composition as a resin (dispersant) for dispersing the coloring material and as a resin (binder) for fixing the coloring material to the fabric.

[0149] The ink composition is a raw material for printing fabrics.

[0150] Examples of fabrics include natural fibers and chemical fibers. Examples of natural fibers include cotton, silk, wool, and hemp. Examples of chemical fibers include polypropylene fibers, polyester fibers, and polyamide fibers.

[0151] The ink composition contains a colorant and the polyurethane dispersion.

[0152] The coloring material is not particularly limited, and known coloring materials can be used.

[0153] The polyurethane dispersion is a component in the ink composition that disperses the coloring material or fixes the coloring material to the fabric.

[0154] When the polyurethane dispersion is used as a resin for dispersing a colorant, the blending ratio of the polyurethane dispersion is, for example, 500 parts by mass to 1000 parts by mass relative to 100 parts by mass of the colorant. When the polyurethane dispersion is used as a resin for fixing a colorant to a fabric, the blending ratio of the polyurethane dispersion is, for example, 3% by mass to 25% by mass relative to the ink composition.

[0155] The ink composition is prepared by mixing a colorant (including a colorant dispersed in a resin other than the polyurethane dispersion) and a polyurethane dispersion.

[0156] Furthermore, if necessary, known additives (for example, humectants, penetrants, chelating agents, preservatives, and pH adjusters) can also be blended into the ink composition. That is, the ink composition contains known additives if necessary. The humectants, penetrants, chelating agents, preservatives, and pH adjusters described in JP 2021-165353 A can be used.

[0157] The ink composition can also be diluted with water and / or an organic solvent (e.g., ethylene glycol).

[0158] Next, a method for printing fabric using this ink composition will be described in detail.

[0159] In order to print a fabric using the ink composition, the fabric is first pretreated as necessary.

[0160] To pretreat the fabric, the fabric is treated with a pretreatment agent (eg, an organic acid).

[0161] Next, the ink composition is applied to the fabric. A known method (e.g., a spray method or an inkjet method) is selected as the method for applying the ink composition to the fabric. In this manner, the ink composition is applied to the fabric.

[0162] Next, the fabric (the fabric to which the ink composition has been applied) is heated.

[0163] The heating temperature is, for example, 80° C. or more, preferably 100° C. or more, and for example, 180° C. or less. The heating time is, for example, 1 minute or more, preferably 5 minutes or more, and for example, 60 minutes or less, preferably 30 minutes or less, more preferably 15 minutes or less.

[0164] This results in printing of the fabric (i.e., obtaining a printed product).

[0165] The ink composition contains the polyurethane dispersion described above, and therefore it is possible to produce printed items that are excellent in mechanical stability, fastness, and texture.

[0166] <Effects> In the polyurethane dispersion, the chain extender contains a trifunctional amine, which improves mechanical stability.

[0167] In addition, in this polyurethane dispersion, the acid value of the polyurethane resin is 6.5 mgKOH / g or more, which improves the mechanical stability.

[0168] In this polyurethane dispersion, the polyurethane resin has an acid value of 15.5 mgKOH / g or less, a weight-average molecular weight of 50,000 or more, and a total of a urethane group concentration and a urea group concentration of 20.0 mass% or less, thereby improving fastness and texture when used for printing fabrics.

[0169] Specifically, when the weight average molecular weight of a polyurethane resin is small, such as the water-soluble urethane resin of Patent Document 1, fastness tends to decrease when a fabric is printed.

[0170] On the other hand, from the viewpoint of improving fastness, increasing the weight-average molecular weight of the water-soluble urethane resin has been considered, but increasing the weight-average molecular weight of the polyurethane resin tends to decrease the mechanical stability. In other words, fastness and mechanical stability have a trade-off relationship. Furthermore, from the viewpoint of improving texture, decreasing the acid value, urethane group concentration, and urea group concentration of the polyurethane resin has been considered, but decreasing the acid value, urethane group concentration, and urea group concentration of the polyurethane resin tends to decrease the mechanical stability. In other words, texture and mechanical stability also have a trade-off relationship.

[0171] In contrast, in the polyurethane dispersion, the weight-average molecular weight of the polyurethane resin is 50,000 or more, and the chain extender contains a trifunctional amine. Because the weight-average molecular weight of the polyurethane resin is 50,000 or more, fastness can be improved when printing fabrics, and because the chain extender contains a trifunctional amine, coalescence of particles can be suppressed by the trifunctional amine, even if the weight-average molecular weight of the polyurethane resin is 50,000 or more, and mechanical stability can be improved.

[0172] Furthermore, by setting the acid value of the polyurethane resin and the total of the urethane group concentration and urea group concentration of the polyurethane resin within a predetermined range, it is possible to improve all of the mechanical stability, fastness, and texture.

[0173] Specific numerical values ​​of the blending ratios (content ratios), physical property values, parameters, etc. used in the following description can be replaced with the upper limit values ​​(numerical values ​​defined as "not more than" or "less than") or lower limit values ​​(numerical values ​​defined as "not less than" or "exceeding") of the corresponding blending ratios (content ratios), physical property values, parameters, etc. described in the above "Modes for Carrying Out the Invention." Furthermore, unless otherwise specified in the following description, "parts" and "%" are based on mass.

[0174] <Component details> IPDI: Isophorone diisocyanate, manufactured by Evonik H １２ MDI: Dicyclohexylmethane diisocyanate, manufactured by Evonik 1,3-H ６ XDI: 1,3-bis(isocyanatomethyl)cyclohexane, manufactured by Mitsui Chemicals, 1,4-H ６XDI: 1,4-bis(isocyanatomethyl)cyclohexane, manufactured by Mitsui Chemicals HDI: hexamethylene diisocyanate, manufactured by Tosoh PDI: pentamethylene diisocyanate, manufactured by Mitsui Chemicals XDI: xylylene diisocyanate, manufactured by Mitsui Chemicals UH-200: polycarbonate diol (molecular weight 2000), manufactured by Ube Industries UH-50: polycarbonate diol (molecular weight 500), manufactured by Ube Industries C-2090: polycarbonate diol (molecular weight 2000), manufactured by Kuraray PTMG-2000: polytetramethylene ether glycol (molecular weight 2000), manufactured by Mitsubishi Chemical P-2020: polyester polyol (reaction product of terephthalic acid and 3-methyl-1,5-pentanediol), manufactured by Kuraray DMPA: dimethylolpropionic acid, manufactured by Perstorp TEA: Triethylamine, manufactured by Wako Pure Chemical Industries, Ltd. TMA: Trimethylamine (13% by mass acetonitrile solution), manufactured by Tokyo Chemical Industry Co., Ltd. DETA: Diethylenetriamine, manufactured by Wako Pure Chemical Industries, Ltd. TAEA: Tris(2-aminoethyl)amine, manufactured by Tokyo Chemical Industry Co., Ltd. EDA: 1,2-ethylenediamine, manufactured by Wako Pure Chemical Industries, Ltd. HYD·H ２ O: Hydrazine monohydrate, manufactured by Wako Pure Chemical Industries, Ltd. AEAE: 2-(2-aminoethylamino)ethanol, manufactured by Wako Pure Chemical Industries, Ltd. DEA: Diethylamine, manufactured by Wako Pure Chemical Industries, Ltd. TETRA: Triethylenetetramine, manufactured by Wako Pure Chemical Industries, Ltd. AN: Acetonitrile THF: Tetrahydrofuran AC: Acetone

[0175] Preparation of Polyurethane Dispersion Example 1 A four-neck flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen inlet tube was charged with 271.5 parts by mass of UH-200, 7.7 parts by mass of DMPA (a hydrophilic group-containing active hydrogen compound), and 79.1 parts by mass of acetonitrile. Next, 60.1 parts by mass of IPDI was added, and a urethane-forming reaction was carried out at 80°C until the isocyanate group concentration reached 1.6% by mass, thereby obtaining an isocyanate group-terminated prepolymer (a reaction liquid containing an isocyanate group-terminated prepolymer).

[0176] Next, 265.8 parts by mass of acetonitrile was added to this reaction liquid, and after cooling to 30° C., 5.7 parts by mass of TEA (neutralizing agent) was added.

[0177] Next, 724.1 parts by mass of ion-exchanged water (aqueous dispersion) was gradually added while continuing stirring to disperse the isocyanate-terminated prepolymer in water, thereby preparing an aqueous dispersion of the isocyanate-terminated prepolymer.

[0178] Next, 20.0 parts by mass of a 20% by mass aqueous solution of diethylenetriamine (4.0 parts by mass as diethylenetriamine) and 4.5 parts by mass of a 20% by mass aqueous solution of ethylenediamine (0.9 parts by mass as ethylenediamine) were added to the aqueous dispersion of the isocyanate group-terminated prepolymer, and then the mixture was allowed to react for 1 hour.

[0179] Next, acetonitrile was distilled off under reduced pressure at 50° C., and ion-exchanged water was added to prepare a polyurethane dispersion (solid content: 35% by mass).

[0180] Examples 2 to 22, Comparative Examples 1 to 7, 9 and 10 Polyurethane dispersions (solid content 35% by mass) were prepared according to the same procedure as in Example 1. However, the formulations were changed according to Tables 1 to 8.

[0181] Comparative Example 8 A water-soluble urethane resin UR8 described in JP-A No. 2022-93959 was prepared.

[0182] [Acid Value] The acid value of the polyurethane dispersion of each Example and Comparative Example was calculated from the charging ratio of the raw material components. Specifically, the acid value was calculated based on the following formula (1). The results are shown in Tables 1 to 8. 56100 / {(mass of polyisocyanate component + mass of polyol component + mass of neutralizing agent + mass of chain extender) / (number of moles of carboxyl groups derived from hydrophilic group-containing active hydrogen compound)} (1)

[0183] [Total of Urethane Group Concentration and Urea Group Concentration] The total of the urethane group concentration and urea group concentration of the polyurethane dispersion of each Example and Comparative Example was calculated from the charging ratio of the raw material components. Specifically, the total of the urethane group concentration and urea group concentration of the polyurethane dispersion was calculated based on the following formula (2). The results are shown in Tables 1 to 8. {59 × (number of moles of hydroxyl groups derived from the polyol component) + 58 × (number of moles of amino groups having active hydrogen groups derived from the chain extender)} / (mass of polyisocyanate component + mass of polyol component + mass of neutralizing agent + mass of chain extender) × 100 (2)

[0184] [Filterability] 20 mL of the polyurethane dispersion (solid content concentration 35% by mass) of each Example and Comparative Example was sucked up into a syringe and extruded with a 0.45 μm or 0.80 μm syringe filter attached, and the filtration rate was calculated. In other words, the filtration rate when the entire 20 mL could be extruded was 100%. The results are shown in Tables 1 to 8.

[0185] [Mechanical Stability (Foreign Matter Formation Rate)] The polyurethane dispersion of each Example and Comparative Example was diluted with ion-exchanged water to prepare 100 g of polyurethane dispersion with a solid content concentration of 20 mass %.

[0186] The resulting polyurethane dispersion was then heated to 60°C, and its mechanical stability was evaluated using a Maron mechanical stability tester (manufactured by Tester Sangyo Co., Ltd.). The test conditions were a load of 15.0±0.5 kg, a rotation speed of 1000 rpm, and a test time of 15 minutes. If a large amount of foreign matter was produced and the load was not stable, the time when the test was interrupted was used as the test time.

[0187] After the test, the foreign matter generated was collected and dried at 150°C for 1 hour, and the amount of foreign matter generated was measured. The foreign matter generation rate was calculated using the following formula. The lower the foreign matter generation rate, the better the mechanical stability. (Foreign matter generation rate (g / min)) = (Amount of foreign matter generated (g)) / Test time (min)

[0188] [Shrinkage during drying] 7.0 g of the polyurethane dispersion of each Example and Comparative Example was spread evenly on a disposable PP tray (150 × 105 × 19 mm) and subjected to heat treatment at 110°C for 1 hour to form a coating film with a thickness of approximately 200 µm.

[0189] The resulting coating film was visually observed. The shrinkage of the coating film was evaluated according to the following criteria: {Criteria} Good: No shrinkage of the coating film was observed. Poor: The coating film shrunk and curled in parts.

[0190] [Tackiness] The coating film obtained in the evaluation of shrinkage upon drying was inspected by touch with a finger. The tackiness was evaluated according to the following criteria. {Criteria} 3: No stickiness was felt. 2: Slight stickiness was felt. 1: Stickiness was felt.

[0191] [Texture] Kanakin No. 3 (100% cotton) fabric was cut into a size of 210 mm lengthwise and 30 mm widthwise to prepare a woven fabric.

[0192] Next, 34.3 g of the polyurethane dispersion (solid content concentration 35% by mass) of each Example and Comparative Example, 8.0 g of a colorant (Dystone X Color Blue MX, manufactured by Matsui Pigment Chemical Industry Co., Ltd., active ingredient 25% by mass), 20.0 g of ethylene glycol, and 37.7 g of water were mixed to prepare an ink composition.

[0193] Next, the fabric was impregnated with the ink composition, and about 1.5 g of the ink composition was soaked into the fabric. Thereafter, the fabric was heat-treated at 150° C. for 10 minutes. This gave a printed item.

[0194] The printed textile was observed with a touch. The texture was evaluated according to the following criteria. The results are shown in Tables 1 to 8. {Criteria} 3: Felt slightly flexible. 2: Felt slightly hard. 1: Hard.

[0195] [Fastness (Color Transfer)] Kanakin No. 3 was cut into a piece of 50 mm length and 50 mm width, and moistened with distilled water to prepare a white friction cloth.

[0196] The printed fabric and the white cloth for rubbing used in the evaluation of texture were attached to a No. 428 Gakushin-type abrasion tester (Yasuda Seiki Seisakusho Co., Ltd., Friction Tester Type II), and tested under a load of 200 g, a swing width of 100 mm, and 100 reciprocal cycles (30 cycles / min).

[0197] The obtained white friction cloth was measured for its L value (the higher the value, the whiter the cloth and the less the degree of contamination) using a spectrocolorimeter (Spectro Color Meter 2000, Nippon Denshoku Industries Co., Ltd.). The L value of the white friction cloth before the test was 90 or more. Color transfer was evaluated according to the following criteria. The results are shown in Tables 1 to 8. (Criteria) 3: The L value was 75 or more. 2: The L value was 70 or more but less than 75. 1: The L value was 70 or less.

[0198]

[0199]

[0200]

[0201]

[0202]

[0203]

[0204]

[0205]

[0206] The above invention is provided as an exemplary embodiment of the present invention, but this is merely an example and should not be interpreted as limiting. Modifications of the present invention that are obvious to those skilled in the art are intended to be included in the scope of the following claims.

[0207] The polyurethane dispersion and ink composition of the present invention can be suitably used, for example, when printing fabrics.

Claims

1. A polyurethane dispersion in which a polyurethane resin is dispersed in water, wherein the polyurethane resin is a reaction product of an isocyanate-terminated prepolymer and a chain extender, the isocyanate-terminated prepolymer is a reaction product of a polyisocyanate component and a polyol component containing a macropolyol and a hydrophilic group-containing active hydrogen compound, the chain extender contains a trifunctional amine, the acid value of the polyurethane resin is 6.5 mg KOH / g or more and 15.5 mg KOH / g or less, the sum of the urethane group concentration and the urea group concentration of the polyurethane resin is 20.0 mass% or less, and the weight average molecular weight of the polyurethane resin is 50,000 or more.

2. The polyurethane dispersion according to claim 1, wherein the chain extender contains other amines, the other amines being monofunctional amines and difunctional amines, and the amine equivalent ratio of the trifunctional amine to the other amines is 0.17 or more and 5.67 or less.

3. The polyurethane dispersion according to claim 1, wherein the weight average molecular weight of the polyurethane resin is 200,000 or more.

4. An ink composition comprising the polyurethane dispersion according to any one of claims 1 to 3.

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