JP7293103B2 - White ink composition for inkjet textile printing - Google Patents

Description

TECHNICAL FIELD The present invention relates to a white ink composition for inkjet textile printing, a method for producing the same, an ink set for inkjet textile printing, and an inkjet textile printing method.

Textile printing is a coloring method for applying patterns to fabrics and textile products, and screen textile printing and roller textile printing are widely used. .
The inkjet textile printing method is a method of printing by ejecting ink droplets and attaching them to a fabric, and has the advantage that the mechanism is relatively simple and high-definition and high-quality images can be formed. In addition, unlike conventional methods, there is no need to create a plate, so images with excellent gradation can be formed quickly, making it possible to handle small-lot, high-mix production. etc., are environmentally friendly.

Textile inks include dye inks and pigment inks. Pigment ink is advantageous over dye ink in that it has high light resistance and does not require post-treatment such as washing.
However, pigment inks require the addition of a fixing resin as a binder component in order to fix the pigments to the fibers and improve the fastness. The fixing resin forms a thin film on the surface of the fabric by being heated after droplets of water-based ink land on the surface of the fabric. It is believed that water-based ink containing a fixing resin can enhance the fastness of an image formed on a fabric by retaining the pigment in the film. However, there is a problem that the fabric feels stiff due to the hardness derived from the fixing resin, and the texture of the fiber is inferior to that of the dye ink.

Various proposals have been made as inkjet textile printing inks for improving the feel, durability, etc. of printed textiles.
For example, Patent Document 1 describes a white ink composition for inkjet textile printing that has a high degree of whiteness, does not impair the texture, and provides a dyed product with excellent coating durability and the like. An ink composition containing a resin emulsion and an aqueous medium, wherein a polymeric dispersant neutralizes an anionic water-soluble resin having a specific glass transition temperature (Tg), acid value, and weight average molecular weight. Disclosed is a white ink composition which is a molecular dispersant (A), the nonionic resin emulsion is a nonionic resin emulsion (B) having a Tg of 20° C. or less, and the (A) and (B) have a specific mass ratio. It is
Patent Document 2 describes an ink composition for inkjet textile printing that provides printed textiles with excellent abrasion resistance and flexibility, containing a pigment, a urethane resin emulsion, an emulsion-type silicone compound, and water, and containing a urethane resin emulsion. 3.5 to 14% by weight, an emulsion type silicone compound content of 0.4 to 3% by weight, and a water content of 20 to 80% by weight.
Patent Document 3 describes an ink composition for inkjet textile printing that provides sharpness of printed images and durability against external stresses such as scratches and rubbing without impairing the texture of the printed material. An ink composition is disclosed containing a binder component, an aqueous medium and a polyalkylsiloxane emulsion wax.

JP 2008-195767 A JP 2013-194222 A JP 2011-105915 A

In Patent Document 1, an acrylic nonionic resin emulsion having a Tg of 20° C. or less is used as a fixing resin in the ink in order to maintain the texture of the fabric. was enough.
In Patent Document 2, in addition to pigments and urethane-based fixing resin, an attempt is made to improve the flexibility by using emulsion-type silicone oil in combination with the ink. It was inadequate in terms of durability.
In Patent Document 3, in addition to the pigment and the acrylic fixing resin, an attempt is made to improve the texture by using polyalkylsiloxane emulsion wax in combination. , there is a problem that the suitability for superimposition with inks of other colors is lowered.
The present invention provides a white ink composition for inkjet textile printing that does not impair the texture of printed textiles and is excellent in durability against external stress such as rubbing, a method for producing the same, an ink set for inkjet textile printing, and an inkjet textile printing method. is the subject.

The present inventors used two types of fixing resins, ie, first and second fixing resins having different elastic moduli, as the fixing resins contained in the ink. The inventors have found that the above problems can be solved by setting the content to a specific range.
That is, the present invention provides the following [1] to [4].
[1] A white ink composition for inkjet textile printing containing a pigment, a fixing resin, and water, wherein the fixing resin includes a first fixing resin and a second fixing resin having different elastic moduli,
The elastic modulus of the first fixing resin at 23° C. is 1×10 ⁴ Pa or more and less than 1×10 ⁶ Pa, and the elastic modulus of the second fixing resin at 23° C. is 1×10 ⁶ Pa or more and 1×10. ⁸ Pa or less,
mass ratio of the first fixing resin to the total fixing resin is 0.2 or more and 0.8 or less;
A white ink composition for inkjet textile printing.
[2] A pigment, a first fixing resin having an elastic modulus of 1×10 ⁴ Pa or more and less than 1×10 ⁶ Pa at 23° C., and an elastic modulus of 1×10 ⁶ Pa or more and 1×10 ⁸ Pa or less at 23° C. and the second fixing resin and water.
[3] An ink set for inkjet textile printing, comprising the white ink composition described in [1] above and a treatment liquid containing a polyvalent metal salt.
[4] An inkjet textile printing method comprising the following steps 1 to 3.
Step 1: A step of attaching a treatment liquid containing a polyvalent metal salt to a fabric to obtain a treated fabric Step 2: The white ink composition described in [1] above is applied to the treated fabric obtained in Step 1 by inkjet. Step 3: Drying the printed fabric obtained in Step 2.

INDUSTRIAL APPLICABILITY According to the present invention, there are provided a white ink composition for inkjet textile printing that does not impair the texture of printed textiles and is excellent in durability against external stress such as rubbing, a method for producing the same, an ink set for inkjet textile printing, and an inkjet textile printing method. can do.

[White ink composition for inkjet textile printing]
The white ink composition for inkjet textile printing of the present invention (hereinafter also simply referred to as "the ink of the present invention") is a white ink composition for inkjet textile printing containing a pigment, a fixing resin, and water, wherein the fixing resin is , including a first fixing resin and a second fixing resin having different elastic moduli,
The first fixing resin has an elastic modulus of 1.0×10 ⁴ Pa or more and less than 1.0×10 ⁶ Pa at 23° C., and the second fixing resin has an elastic modulus of 1.0×10 at 23° C. ⁶ Pa or more and 1.0 × 10 ⁸ Pa or less,
The mass ratio of the first fixing resin to the total fixing resin is 0.2 or more and 0.8 or less.
As used herein, “inkjet textile printing” refers to printing ink on the surface of a fabric, which is a printing medium, using an inkjet method, and “printed fabric” means printing on the surface of a fabric, which is a printing medium. An image formed by imprinting (printing) ink.

According to the ink of the present invention, it is possible to obtain a printed fabric excellent in durability against external stress such as rubbing without impairing the texture of the fabric. Although the reason is not clear, it is considered as follows.
In the present invention, as the fixing resin, a first fixing resin having an elastic modulus of 1×10 ⁴ Pa or more and less than 1×10 ⁶ Pa and an elastic modulus of 1×10 ⁶ Pa or more and 1×10 ⁸ Pa or less are used. By using the second fixing resin, after the ink lands on the fabric and the water is adsorbed by the fibers, the fixing resin quickly spreads uniformly on the fiber surface of the fabric, and the pigment particles are removed from the outside. can be protected from stresses of
In addition, the coating film of this fixing resin maintains flexibility, and by setting the mass ratio of the first fixing resin to the total fixing resin to 0.2 or more and 0.8 or less, the fiber surface of the fabric is It is considered that the coating is properly performed and the occurrence of stiffness can be suppressed.

<Pigment>
The pigment used in the present invention is a white pigment, preferably an inorganic pigment.
Examples of inorganic pigments include metal oxides such as titanium dioxide, zinc oxide, silica, alumina and magnesia, metal sulfates such as calcium sulfate and barium sulfate, and metal carbonates such as calcium carbonate and magnesium carbonate. Among these, from the viewpoint of obtaining a high degree of whiteness, metal oxides such as titanium dioxide, zinc oxide, silica, alumina, and magnesia are preferred, and one or more selected from titanium dioxide and zinc oxide are more preferred, and titanium dioxide is preferred. More preferred.
The pigments may be used alone or in combination of two or more.

As titanium dioxide, rutile-type titanium dioxide and anatase-type titanium dioxide can be used, but from the viewpoint of stability and availability, rutile-type titanium dioxide is preferable.
Titanium dioxide is preferably surface-treated from the viewpoint of obtaining good dispersibility in the ink of the present invention. The surface treatment of titanium dioxide is not particularly limited, and may be either surface treatment with an organic substance or surface treatment with an inorganic substance. From the viewpoint of avoiding photocatalytic effects, titanium oxide surface-treated with an inorganic substance is preferred, and titanium dioxide surface-treated with silica and alumina is more preferred.
The average primary particle size of titanium dioxide is preferably 100 nm or more, more preferably 150 nm or more, and still more preferably 200 nm or more, from the viewpoint of whiteness, and preferably 500 nm or less, more preferably from the viewpoint of redispersibility. is 400 nm or less, more preferably 350 nm or less, still more preferably 300 nm or less.
The average primary particle size of titanium oxide is measured by the method described in Examples.
Commercially available examples of rutile-type titanium dioxide include the trade names of Typaque R, CR, and PF series manufactured by Ishihara Sangyo Co., Ltd., the trade names of R series manufactured by Sakai Chemical Industry Co., Ltd., and the trade names of JR manufactured by Tayca Corporation. , MT series, Titan Kogyo Co., Ltd. trade name: KURONOS KR series, Fuji Titanium Kogyo Co., Ltd. trade name: TR series, and the like.

The pigment used in the ink of the present invention is preferably held in a dispersed state in the ink by a dispersant. A polymer dispersant is preferred as the dispersant for dispersing the pigment.
The form of the pigment and polymer dispersant in the ink of the present invention is more preferably in the form of polymer particles containing the pigment (hereinafter also referred to as "pigment-containing polymer particles").
Pigment-containing polymer particles include particles in which a polymer dispersant encloses a pigment, particles in which a part of the pigment is exposed on the surface of particles composed of a polymer dispersant and a pigment, and particles in which the polymer dispersant is a part of the pigment. It means any of the particles in the form adsorbed to the part or a mixture thereof.

(Polymer dispersant)
The polymer dispersant preferably has a structural unit derived from the anionic group-containing monomer (a) from the viewpoint of improving the durability against external stress without impairing the texture of the printed fabric.
The polymer dispersant may further contain a structural unit derived from the nonionic monomer (b) or a structural unit derived from the hydrophobic monomer (c) within a range that does not impair the effects of the present invention.

(Anionic group-containing monomer (a))
Examples of the anionic group in the anionic group-containing monomer (a) include a carboxylic acid group, a sulfonic acid group, a phosphoric acid group, and the like, and a carboxylic acid group is preferable from the viewpoint of dispersion stability and ejection stability.
Examples of the monomer having a carboxylic acid group include monocarboxylic acid monomers such as (meth)acrylic acid and crotonic acid, and dicarboxylic acid monomers such as fumaric acid, maleic acid and itaconic acid. Acrylic acid, more preferably methacrylic acid.
In addition, "(meth)acrylic acid" means one or more selected from acrylic acid and methacrylic acid. "(Meth)acrylic acid" below has the same meaning.

It is preferred that some or all of the anionic groups of the polymeric dispersant are neutralized. By being neutralized, the polymer dispersant becomes ionic and can disperse titanium oxide in an aqueous medium.
Basic compounds as neutralizing agents include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide and potassium hydroxide, ammonia, water-soluble organic amine compounds and the like, but alkali metal hydroxides are preferred. , sodium hydroxide is more preferred.

(Nonionic monomer (b))
The nonionic monomer (b) includes 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, polyalkylene glycol (meth) acrylate, alkoxypolyalkylene glycol (meth) acrylate and the like. Alkylene glycol (meth)acrylates are preferred.
In addition, "(meth)acrylate" means one or more selected from acrylate and methacrylate. "(Meth)acrylate" below has the same meaning.
A structural unit derived from polyalkylene glycol (meth)acrylate is specifically represented by the following formula (1).

In formula (1), R ¹ represents a hydrogen atom or a methyl group, R ² represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, OA represents an oxyalkylene group having 2 to 4 carbon atoms, n represents the average number of added moles of (OA) and is a number of 4 or more and 100 or less. However, the n oxyalkylene groups may be the same or different.

In formula (1), R ¹ is preferably a methyl group.
In formula (1), R ² is preferably a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, still more preferably a methyl group. is. The alkyl group may be straight or branched.
The oxyalkylene group (OA) includes an oxyethylene group, an oxypropylene group and an oxybutylene group, preferably one or more selected from an oxyethylene group and an oxypropylene group, more preferably oxyethylene is the base.
The average number of added moles of (OA), n, is preferably 8 or more, more preferably 12 or more, and is preferably 100 or less, more preferably 50 or less, and still more preferably 25 or less. When a plurality of (OA) are different from each other, either block addition, random addition, or alternate addition may be used.

Examples of the structural unit monomer represented by formula (1) include polyethylene glycol mono(meth)acrylate; methoxypolyethylene glycol mono(meth)acrylate, ethoxypolyethyleneglycol mono(meth)acrylate, propoxypolyethyleneglycol mono(meth)acrylate, One or more selected from alkoxypolyethylene glycol mono(meth)acrylates such as butoxypolyethyleneglycol mono(meth)acrylate, octoxypolyethyleneglycol mono(meth)acrylate, and stearoxypolyethyleneglycol mono(meth)acrylate can be mentioned. Among these, alkoxypolyethylene glycol mono(meth)acrylates are preferred, and at least one selected from methoxypolyethyleneglycol mono(meth)acrylate, ethoxypolyethyleneglycol mono(meth)acrylate, and propoxypolyethyleneglycol mono(meth)acrylate. More preferred is methoxypolyethylene glycol mono(meth)acrylate.
Examples of commercially available nonionic monomers (b) include NK Ester M-230G, 450G, 900G (manufactured by Shin-Nakamura Chemical Co., Ltd.), Blenmer PME-1000, 4000 (manufactured by NOF Corporation (manufactured by Kyoeisha Chemical Co., Ltd.), Light Ester 041MA (manufactured by Kyoeisha Chemical Co., Ltd.), and the like.

(Hydrophobic monomer (c))
Examples of the hydrophobic monomer (c) include one or more selected from alkyl (meth)acrylates, aromatic group-containing monomers, and the like.
The alkyl (meth)acrylate preferably has an alkyl group having 1 to 22 carbon atoms, preferably 6 to 18 carbon atoms, such as methyl (meth)acrylate, ethyl (meth)acrylate, (isopropyl (meth)acrylate), ) acrylate, (iso- or tertiary) butyl (meth) acrylate, (iso) amyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (iso) octyl (meth) acrylate, (iso) Decyl (meth)acrylate, (iso)dodecyl (meth)acrylate, (iso)stearyl (meth)acrylate and the like.
In addition, "(iso or tertiary)" and "(iso)" mean both when these groups are present and when these groups are not present, and when these groups are not present, normal is indicated.
The aromatic group-containing monomer, which may have a substituent containing a hetero atom, is preferably a vinyl monomer having an aromatic group having 6 to 22 carbon atoms, a styrene-based monomer, an aromatic group-containing (meth)acrylate is more preferable, and these may be used in combination.
Styrene-based monomers are preferably styrene, 2-methylstyrene, and divinylbenzene, and more preferably styrene.
As the aromatic group-containing (meth)acrylate, benzyl (meth)acrylate, phenoxyethyl (meth)acrylate and the like are preferable, and benzyl (meth)acrylate is more preferable.

The content of the structural units derived from the anionic group-containing monomer (a) in all the structural units of the polymer dispersant is preferably 3% by mass or more, more preferably 5% by mass or more, from the viewpoint of dispersion stability and the like. It is preferably 10% by mass or more, more preferably 15% by mass or more, and preferably 100% by mass or less, most preferably 100% by mass.
The polymer dispersant preferably does not contain structural units derived from the nonionic monomer (b), and the content of the structural units is preferably 40% by mass or less, more preferably 30% by mass or less, and still more preferably 20% by mass. % or less, more preferably 10 mass % or less.
The polymer dispersant preferably does not contain a structural unit derived from the hydrophobic monomer (c), and the content thereof is preferably 20% by mass or less, more preferably 10% by mass or less, still more preferably 5% by mass or less, Even more preferably, it is 3% by mass or less.

The acid value of the polymer dispersant is preferably 100 mgKOH/g or more, more preferably 200 mgKOH/g or more, still more preferably 400 mgKOH/g or more, still more preferably 600 mgKOH/g or more, and preferably 1000 mgKOH/g or more. g or less, more preferably 900 mgKOH/g or less, still more preferably 800 mgKOH/g or less.
The method for measuring the acid value conforms to the JIS K 0070 potentiometric titration method.
The polystyrene equivalent weight average molecular weight of the polymer dispersant is preferably 2,000 or more, more preferably 3,000 or more, still more preferably 4,000 or more, and preferably 4, from the viewpoint of dispersion stability and the like. 10,000 or less, more preferably 30,000 or less, and still more preferably 20,000 or less.
A commercial product can also be used for the polymer dispersant. Examples of commercially available products include polyacrylic acid manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., trade name of Kao Corporation: Poise 520, special polycarboxylic acid such as Poise 530, and trade name of Toagosei Co., Ltd.: Aron 6012. Aron series water-soluble acrylic acid-based dispersants such as
The weight average molecular weight of the polymer is measured by the method described in Examples.

A polymer dispersant can be produced by copolymerizing a monomer mixture containing the above monomers by a known polymerization method. Specifically, it can be obtained by the method described in paragraphs [0021] and [0022] of JP-A-2017-75302. Moreover, you may purchase and use a commercial item.

<Fixing resin>
The fixing resin is used to form a film when the ink of the present invention is applied to the fabric to impart durability against external stress to the printed fabric. In the present invention, the fixing resin contains at least two of a first fixing resin and a second fixing resin.

(First fixing resin)
The first fixing resin has an elastic modulus of 1×10 ⁴ Pa or more and less than 1.0×10 ⁶ Pa at 23°C.
The elastic modulus of the first fixing resin is preferably 2×10 ⁴ Pa or more, more preferably 5×10 ⁴ Pa or more at 23° C., from the viewpoint of maintaining good texture of the fabric. It is 5×10 ⁵ Pa or less, more preferably 1×10 ⁵ Pa or less.
Elastic modulus is measured by the method described in Examples.
The first fixing resin preferably contains a silicone group.
The content of the silicone groups in the first fixing resin, that is, the ratio of the silicone groups to the entire first fixing resin, is preferably 30% by mass or more, more preferably 35% by mass, from the viewpoint of maintaining good texture of the fabric. % by mass or more, more preferably 40% by mass or more, and preferably 80% by mass or less, more preferably 70% by mass or less, and even more preferably 60% by mass or less.
The silicone group content of the first fixing resin is measured by the method described in Examples.
The first fixing resin is preferably used in an emulsion state.
The first fixing resin can be synthesized, but a commercially available product may be used. modulus: 8.4×10 ⁴ Pa), CHALINE FE502 (silicone acrylic resin water-based emulsion, modulus of elasticity at 23° C.: 25×10 ⁴ Pa), CHALINE NS-651 (silicone acrylic resin water-based emulsion, elasticity at 23° C. modulus: 89×10 ⁴ Pa), Charine LC-190 (silicone acrylic resin water-based emulsion, elastic modulus at 23° C.: 28×10 ⁴ Pa).

(Second fixing resin)
The second fixing resin has an elastic modulus at 23° C. of 1×10 ⁶ Pa or more and 1×10 ⁸ Pa or less.
The elastic modulus of the second fixing resin is preferably 2×10 ⁶ Pa or more, more preferably 3×10 ⁶ Pa or more at 23° C., from the viewpoint of enhancing the durability of the resulting printed material against external force. , and preferably 5×10 ⁷ Pa or less, more preferably 1×10 ⁷ Pa or less.
The second fixing resin preferably does not contain silicone groups. Since the second fixing resin does not contain a silicone group, it is possible to increase the elastic modulus of the resin and increase the durability of the resulting printed material against external force.
Preferable examples of the second fixing resin include urethane resin, polyester resin, acrylic resin, etc. Among these, urethane resin is preferable.

Examples of the urethane resin include a polycarbonate urethane resin having a carbonate bond, a polyester urethane resin having an ester bond, and a polyether urethane resin having an ether bond. From the viewpoint, a polycarbonate-based urethane resin is preferable. The polycarbonate-based urethane resin preferably contains crosslinkable groups such as isocyanate groups and silanol groups.
The second fixing resin is preferably used in an emulsion state.
The second fixing resin can be synthesized, but a commercially available product may also be used. Examples of commercially available polycarbonate-based urethane resins include Superflex 150, 170, 420, and 460 manufactured by Daiichi Kogyo Seiyaku Co., Ltd. , 470, 610, 700, 800, Permaline UA manufactured by Sanyo Kasei Co., Ltd., Ukote UX, and the like.

<Water-soluble organic solvent>
The white ink of the present invention preferably contains a water-soluble organic solvent. The water-soluble organic solvent is used to form a uniform film between the first fixing resin, the second fixing resin, and the pigment, and to adhere this film to the fabric.
From the above viewpoint, the water-soluble organic solvent preferably contains alkylene glycol.
The alkylene glycol is preferably selected from aliphatic diols having 2 or more and 6 or less carbon atoms, more preferably 3 or more and 5 or less carbon atoms, and still more preferably 3 or 4 carbon atoms, from the viewpoint of enhancing affinity with the fixing resin. more preferably one or more selected from propylene glycol (boiling point 187° C.), 1,2-butanediol (boiling point 190° C.), 1,3-butanediol (boiling point 207° C.) and the like, and propylene Glycols are more preferred.
The water-soluble organic solvent may contain an alkylene glycol ether from the viewpoint of forming a good film in the ink of the present invention. Examples of alkylene glycol include monoalkylene glycol ethers in which the alkylene group has 1 to 6 carbon atoms, preferably 3 to 6 carbon atoms. Glycol ethers constituting alkylene glycol ethers include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, isopropyl ether and the like.

<Surfactant>
From the viewpoint of improving ejection stability, the ink of the present invention preferably contains a surfactant. The surfactant is preferably a nonionic surfactant, more preferably one or more selected from silicone surfactants and acetylene glycol surfactants, and at least one silicone surfactant and an acetylene glycol surfactant. is more preferably used in combination of at least two.
Examples of commercially available silicone-based surfactants include the "Silface" series manufactured by Nisshin Chemical Co., Ltd., the "KF" series manufactured by Shin-Etsu Chemical Co., Ltd., and the "BYK" series manufactured by Big Chemie.
Commercially available examples of acetylene glycol-based surfactants include the "Surfinol" series and "Olfine" series manufactured by Air Products and Chemicals Co., Ltd. or Nissin Chemical Industry Co., Ltd., and the "Acetylenol" series manufactured by Kawaken Fine Chemicals Co., Ltd. etc.

[Production of Ink Composition for Inkjet Textile Printing]
The ink of the present invention is prepared by mixing water-insoluble polymer particles containing a pigment, a fixing resin, water, and, if necessary, a water-soluble organic solvent, a surfactant, etc. to prepare an aqueous pigment dispersion. Furthermore, by adding and mixing water, an organic solvent, etc., it can be produced efficiently. There is no particular limitation on the method of mixing them.

The content of each component of the ink of the present invention and the physical properties of the ink are selected from the viewpoints of improving the durability against external stress, improving the printing density, ensuring ejection stability, etc. without impairing the texture of the printed material. From, it is as follows.
(Pigment content)
The content of the pigment in the ink of the present invention is preferably 2% by mass or more, more preferably 5% by mass or more, still more preferably 8% by mass or more, and is preferably 20% by mass or less, more preferably 15% by mass. % or less, more preferably 12 mass % or less.
(Content of pigment-containing polymer particles)
The content of the pigment-containing polymer particles in the ink of the present invention is preferably 3% by mass or more, more preferably 5% by mass or more, still more preferably 8% by mass or more, and preferably 20% by mass or less, more preferably is 15% by mass or less, more preferably 12% by mass or less.

(Content of fixing resin)
The content of the total fixing resin in the ink of the present invention is preferably 2% by mass or more, more preferably 5% by mass or more, still more preferably 8% by mass or more, and preferably 20% by mass or less, more preferably is 15% by mass or less, more preferably 12% by mass or less.
The mass ratio of the first fixing resin to the total fixing resin is 0.2 or more, preferably 0.25 or more, more preferably 0, from the viewpoint of further increasing the durability of the resulting printed material against external force. 0.4 or more, more preferably 0.5 or more, and from the viewpoint of improving the texture of the fabric, it is 0.8 or less, preferably 0.75 or less, more preferably 0.7 or less.
The mass ratio of the fixing resin to the pigment-containing polymer particles [fixing resin/pigment-containing polymer particles] is preferably 0.2 or more, more preferably 0.4 or more, still more preferably 0.6 or more, and It is preferably 2 or less, more preferably 1.8 or less, still more preferably 1.5 or less.

(Content of water-soluble organic solvent)
When the ink of the present invention contains a water-soluble organic solvent, the content is preferably 5% by mass or more, more preferably 10% by mass or more, still more preferably 15% by mass or more, and preferably 45% by mass or less. , more preferably 40% by mass or less, and still more preferably 30% by mass or less.
When the water-soluble organic solvent contains propylene glycol, the ratio of propylene glycol to the entire water-soluble organic solvent is preferably 60% by mass or more, more preferably 80% by mass or more, and still more preferably 90% by mass or more, and It is preferably 100% by mass or less, and most preferably 100% by mass.

(Content of surfactant)
When the ink of the present invention contains a surfactant, the content thereof is preferably 0.5% by mass or more, more preferably 0.7% by mass or more, and still more preferably 0.9% by mass or more. is 2% by mass or less, more preferably 1.7% by mass or less, and still more preferably 1.5% by mass or less.
When the ink of the present invention contains a silicone-based surfactant, the content thereof is preferably 0.01% by mass or more, more preferably 0.02% by mass or more, and preferably 0.2% by mass or less, It is more preferably 0.1% by mass or less, still more preferably 0.05% by mass or less.
When the ink of the present invention contains an acetylene glycol-based surfactant, the content thereof is preferably 0.3% by mass or more, more preferably 0.4% by mass or more, and still more preferably 0.5% by mass or more, The content is preferably 1.5% by mass or less, more preferably 1.3% by mass or less, and even more preferably 1.2% by mass or less.

(water content)
The water content in the ink of the present invention is preferably 30% by mass or more, more preferably 40% by mass or more, still more preferably 45% by mass or more, and preferably 80% by mass or less, more preferably 75% by mass. % or less, more preferably 65 mass % or less.

<Physical properties of water-based ink>
The viscosity at 25° C. of the ink of the present invention is preferably 2 mPa·s or more, more preferably 3 mPa·s or more, still more preferably 4 mPa·s or more, and preferably 20 mPa·s or less, more preferably 15 mPa·s. s or less, more preferably 10 mPa·s or less.
The pH of the ink at 20° C. is preferably 5 or higher, more preferably 6 or higher, still more preferably 7 or higher, and is preferably 11 or lower, more preferably 10 or lower, and still more preferably 9.5 or lower.

[Method for producing white ink composition for inkjet textile printing]
The method for producing a white ink composition for inkjet textile ^printing of the present ^invention comprises: a pigment; A second fixing resin having a pressure of 1×10 ⁶ Pa or more and 1×10 ⁸ Pa or less and water are mixed.
The details of the pigment, the first fixing resin, and the second fixing resin are as described above.
There is no particular limitation on the method of mixing each component, and it can be carried out by a conventional method.

[Ink set for inkjet textile printing]
The ink set for inkjet textile printing of the present invention (hereinafter also simply referred to as "ink set") includes the ink of the present invention and a treatment liquid containing a polyvalent metal salt.
The treatment liquid reacts with components such as the pigment and the fixing resin contained in the ink of the present invention to agglomerate them and deposit the fixing resin to form a strong film on the ink dots on the fabric. It has the action of causing and immobilizing.

(Polyvalent metal salt)
A polyvalent metal salt is a compound composed of a divalent or higher valent metal ion and an anion. Examples of divalent or higher metal ions include ions of calcium, magnesium, copper, nickel, zinc, barium, aluminum, titanium, strontium, chromium, cobalt, and iron. Among these, calcium ions and magnesium ions are preferred, and calcium ions are more preferred, from the viewpoint of improving the durability against external stress without impairing the texture of the printed fabric.
Anions (counter ions of polyvalent metals) constituting polyvalent metal salts include inorganic ions and organic ions, and inorganic ions include chloride ions, bromide ions, iodine ions, nitrate ions, sulfate ions, and hydroxides. ions and the like, and examples of organic ions include organic acid ions such as carboxylate ions.

Specific examples of polyvalent metal salts include calcium chloride, calcium nitrate, calcium sulfate, calcium acetate, calcium hydroxide, calcium carbonate, magnesium chloride, magnesium acetate, magnesium sulfate, magnesium carbonate, barium sulfate, barium chloride, zinc sulfide, zinc carbonate, copper nitrate and the like. The polyvalent metal salt may have water of hydration in the raw material form. Among these, calcium nitrate and calcium chloride are preferred, and calcium nitrate is more preferred, from the viewpoint of ensuring water solubility and reducing traces of the flocculant.
The above polyvalent metal salts can be used singly or in combination of two or more.

The treatment liquid used in the present invention may further contain aggregating agents such as organic acids, cationic resins, and metal chelating agents, if necessary.
Organic acids include poly(meth)acrylic acid, acetic acid, glycolic acid, malonic acid, malic acid, maleic acid, ascorbic acid, succinic acid, glutaric acid, fumaric acid, citric acid, tartaric acid, lactic acid, sulfonic acid, and orthophosphoric acid. etc.
Cationic resins include polyallylamine, polyvinylamine, polyethyleneimine, polydiallyldimethylammonium chloride and the like.
Examples of metal chelating agents include acetylacetone, methyl acetoacetate, and acetylacetone having nitrogen-containing groups on metals such as aluminum, zinc, cadmium, nickel, cobalt, copper, calcium, barium, titanium, manganese, iron, lead, zirconium, chromium, and tin. Examples thereof include metal chelate compounds coordinated with ethyl acetoacetate, ethyl lactate, methyl salicylate, and the like.

The ink set of the present invention preferably contains two or more inks with different hues.
Two or more inks with different hues refer to two or more inks selected from black and chromatic colors. Chromatic colors include colors of different densities such as light cyan, dark yellow, light magenta and light black, in addition to the three subtractive primary colors of magenta, yellow and cyan. Furthermore, adding one or more chromatic colors selected from red, blue, orange, green, and violet is preferable because the color reproduction range can be widened.
The ink set of the present invention includes a combination of two or more of these inks, and includes a two-color ink set, a three-color ink set, a four-color ink set, a five-color ink set, a six-color ink set, a seven-color ink set, and the like. is preferred.
In the present invention, an ink set containing a combination of two or more of the white ink composition according to the present invention and other inks is installed in each color ink cartridge of an inkjet printing apparatus, and each ejection corresponding to each ink cartridge is performed. Each ink droplet can be ejected from the nozzles to print onto the fabric.

[Inkjet printing method]
The inkjet textile printing method of the present invention has the following steps 1 to 3.
Step 1: A step of applying a treatment liquid containing a polyvalent metal salt to a fabric to obtain a treated fabric. Step 2: Applying the ink of the present invention to the treated fabric obtained in Step 1 by an inkjet method to obtain a printed fabric. Step 3: Step of drying the printed fabric obtained in Step 2

Step 1 is a step of applying the treatment liquid to the fabric. There is no particular limitation on the method of applying the treatment liquid to the printed area of the fabric. Either a non-contact method or a contact method may be adopted. Examples of non-contact deposition methods include a method using an inkjet printer, and a method such as an air spray method in which fine droplets are entrained in a gas having a flow velocity. Moreover, as a method of contacting and adhering, a roller pressing method, a brushing method, an immersion method, and the like can be mentioned. Among these, from the viewpoint of minimizing the amount of the liquid component to be applied to the fabric, the non-contact method of adhering the liquid component to the fabric is preferred.
From the viewpoint of printing density, the amount of the treatment liquid applied to the fabric is preferably 1 g/m ² or more, more preferably 2 g/m ² or more, still more preferably 3 g/m 2 or more, and even more preferably 3 g/m ² or more, in terms of mass after drying. It is preferably 4 g/m ² or more, and preferably 40 g/m ² or less, more preferably 30 g/m ² or less, even more preferably 20 g/m ² or less, still more preferably from the viewpoint of not impairing the texture. is 15 g/m ² or less.
The fabric used as the printing medium is not particularly limited, and examples include fabrics made of natural fibers such as cotton, silk, and hemp, synthetic fibers such as rayon fibers, acetate fibers, nylon fibers, and polyester fibers, and two types of these fibers. The mixed spinning fabric etc. which consist of the above are mentioned.

In step 2, the ink of the present invention is applied to the treated fabric obtained in step 1 by an inkjet method to obtain a printed fabric. It is preferable to obtain
A drop-on-demand type device is exemplified as an inkjet textile printing device. Examples of this device include a piezo type using a piezoelectric element provided on the head, a thermal type using heat energy from a heater of a heating resistance element provided on the head, and the like. Among these, a piezo-type ink jet printing device is more preferable.
The printing resolution of the inkjet head is preferably 600 dpi (Dots Per Inch) or more, more preferably 720 dpi or more, from the viewpoint of printing density.

After the step 2, the step 3 is performed, and it is preferable to have the following step 2' in between.
Step 2': Step of printing a color ink on the textile fabric obtained in the step 2 by an inkjet method Examples of the color ink include the chromatic inks described above.
The inkjet method is the same as in step 2.

In step 3, the printed fabric obtained in step 2 is dried.
The method for drying the fabric is not particularly limited, but from the viewpoint of the fixability of the treatment liquid and the color ink, it is preferably 40° C. or higher, more preferably 50° C. or higher, and is suitable for preventing deterioration of the fabric, the treatment liquid, and the color ink. From a viewpoint, it can be dried by heating at preferably 180° C. or lower, more preferably 160° C. or lower for 1 minute or more and 1 hour or less.
Examples of the heating method include a heat press method, a hot air drying method, a normal pressure to high pressure steam method, and a thermofix method using infrared rays (lamp). These drying methods may be used alone or in combination. Among these, the hot air drying method is preferable from the viewpoint of reducing damage to fabrics and the like and drying them efficiently.
After drying, the printed material is washed with water, and if necessary, a soaping treatment for washing off unfixed treatment liquid may be performed.
In this way, a printed fabric having an image derived from the ink set of the present invention formed on the fabric can be obtained.

In the following Production Examples, Preparation Examples, Examples and Comparative Examples, "parts" and "%" are "mass parts" and "mass%" unless otherwise specified. In addition, the measuring method of each physical property etc. is as follows.

(1) Measurement of weight-average molecular weight of polymer Gel chromatography method using a solution obtained by dissolving phosphoric acid and lithium bromide in N,N-dimethylformamide at concentrations of 60 mmol/L and 50 mmol/L, respectively, as an eluent. [Tosoh Corporation GPC apparatus (HLC-8120GPC), Tosoh Corporation column (TSK-GEL, α-M × 2), flow rate: 1 mL / min] using monodisperse polystyrene with a known molecular weight as a standard substance measured by

(2) Measurement of Solid Content Concentration of Pigment Water Dispersion 10.0 g of sodium sulfate that had been homogenized in a desiccator was weighed into a 30 ml polypropylene container (φ: 40 mm, height: 30 mm), and about 1.0 g of a sample was placed therein. After adding 0 g and mixing, accurately weigh, maintain for 2 hours in an environment of 105 ° C. and gauge pressure -0.08 MPa to remove volatiles, and further desiccator at room temperature (25 ° C.) After an additional 15 minutes in the chamber, the mass was measured. The mass of the sample after removing the volatile matter was defined as the solid content, and the mass of the added sample was divided to obtain the solid content concentration.

(3) Measurement of Average Particle Size of Pigment Aqueous Dispersion Cumulant analysis was performed using a laser particle analysis system "ELS-8000" (manufactured by Otsuka Electronics Co., Ltd.) to measure the average particle size. A dispersion diluted with water was used so that the concentration of particles to be measured was 5×10 ⁻³ wt % (converted to solid concentration). The measurement conditions are a temperature of 25 ° C., an angle between the incident light and the detector of 90 °, and the number of times of accumulation of 100 times. The particle size was taken as the average particle size of the particles in the pigment aqueous dispersion.

(4) pH
Using a desktop pH meter "F-71" (manufactured by Horiba, Ltd.) using a pH electrode "6337-10D" (manufactured by Horiba, Ltd.), an aqueous dispersion of white pigment-containing polymer particles at 25 ° C. pH was measured.

(5) Measurement of Elastic Modulus of Fixing Resin A resin dispersion liquid was added dropwise to a 1 L polypropylene disposable beaker (manufactured by AS ONE Co., Ltd.) so that the resin solid content was 3 g, and then purified water was added so that the total amount was 30 g. added. After drying for 72 hours in an environment of 25° C. and a gauge pressure of −0.08 MPa, the pressure was returned to normal and the temperature was raised to 80° C., followed by drying for 6 hours. After the resin film was taken out, it was placed on a silicone film and maintained at a temperature of 150° C. for 3 minutes to obtain a dry resin film.
The thickness of the dry resin film is measured using a slide type M-30 u-mate digital micrometer (manufactured by Sony Magnescale Co., Ltd.), a portion with a thickness of 0.5 mm is selected, and the test piece is measured according to JIS. It was cut into a dumbbell shape with the specified dimensions for K7160-2. Using a Tensilon universal material testing machine (manufactured by A&D Co., Ltd., TENSIRON RTC-1150A), under the conditions of a load full scale of 50 N and a tensile speed of 5 mm / min, dry resin film under an environmental atmosphere of 23 ° C. A tensile test was performed on the specimen.
The elastic modulus of the resin was calculated from the slope of the obtained stress-strain curve. For other detailed conditions, the measurement was performed with reference to JIS-K7161.

(6) Measurement of Silicone Group Amount of Fixing Resin An aqueous dispersion of a silicone group-containing resin was dried, and 100 mg of the dispersion was added to heavy chloroform containing no tetramethylsilane (chloroform-d1 for NMR (deuteration rate 99.8). %), manufactured by Kanto Chemical Co., Ltd.) and diluted with 2.0 ml, and using a 1H-NMR tube with a diameter of 5.0 mm, Agilent-NMR-vnmrs400 (manufactured by Varian, 400 MHz), pulse width: 45 μs (45 ° pulse), observation width: 6410 Hz, waiting time: 10 s, number of times of accumulation: 8 times, measurement temperature: proton NMR measurement was performed under the conditions of room temperature, chemical shift value 0-0.5 ppm (methyl group of tetramethylsilane with the chemical shift value of hydrogen at 0) is calculated. In addition, based on the integral value obtained by measuring a known concentration of tetramethylsilane with the same NMR equipment, the silane in the silicone group-containing resin was regarded as the proton (H) of the methyl group (CH3) directly bonded to the Si element of silicone. The atomic mass was calculated and defined as the amount of silicone groups (% by mass).

(7) Viscosity of ink Using an E-type viscometer “TV-25” (manufactured by Toki Sangyo Co., Ltd., standard cone rotor 1°34′×R24, rotation speed 50 rpm), the viscosity was measured at 25 ° C. .

Production Example 1 (Production of aqueous dispersion of white pigment-containing polymer particles)
In a 2 L plastic container, 6 g of polyacrylic acid (PAA; manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., weight average molecular weight 5000) as a polymer dispersant, 4.2 g of 5N-NaOH aqueous solution, and 4.8 g of ion-exchanged water were added in advance. A material (polymer neutralization degree: 50 mol %) dissolved by mixing was added, and titanium oxide: C.I. I. Pigment White 6 (PW 6, manufactured by Ishihara Sangyo Co., Ltd., trade name: CR-80, rutile type, Al/Si treatment, average primary particle size 250 nm, average particle size: 0.25 μm) 300 g, water was added, 1000 g of zirconia beads were added, and dispersion was performed for 8 hours using a desktop pot mill stand (AS ONE Corporation). The zirconia beads were removed using a metal mesh, and the solid content concentration was adjusted with deionized water to obtain an aqueous dispersion of white pigment-containing polymer particles having an average particle size of 328 nm (solid content concentration: 53.2%, pigment introduction rate : 98%, pH: 7.3).

Example 1 (Preparation of White Ink Composition 1)
In a glass container, 18.8 parts of the aqueous dispersion of the white pigment-containing polymer particles obtained in Production Example 1, 16.3 parts of a silicone acrylic resin water-based emulsion (Charine FE230N) as the first fixing resin, and a second 13.2 parts of carbonate-based urethane resin water-based emulsion (Superflex 460) and 27.9 parts of ion-exchanged water were added as a fixing resin, and the mixture was stirred with a magnetic stirrer for 10 minutes to obtain a mixture Q.
Next, while stirring the mixture Q, 22.5 parts of propylene glycol, 0.025 parts of silicone-based activator SAG005 (manufactured by Shin-Etsu Chemical Co., Ltd.), acetylenic surfactant Surfynol 465 (manufactured by Nissin Chemical Co., Ltd.) ) and 0.5 part of an acetylenic surfactant Surfynol 420 (manufactured by Nissin Chemical Industry Co., Ltd.) were added, and the mixture was stirred for 1 hour. After that, filtration was performed using a 5 μm disposable membrane filter (manufactured by Sartorius, trade name: Minizart) to obtain a white ink composition 1 .

Examples 2-3, Comparative Examples 1-4 (Preparation of White Ink Compositions 2-3, 11-14)
By the same procedure as in Example 1, white ink compositions 2 to 3 and 11 to 14 having the compositions shown in Table 1 were obtained.

Details of the fixing resins shown in Table 1 are as follows.
Charine FE230N (manufactured by Nissin Chemical Industry Co., Ltd., silicone acrylic resin water-based emulsion, silicone group content: 50%, solid concentration: 30.7%), elastic modulus at 23°C: 8.4 × 10 ⁴ Pa
・Superflex 460 (Daiichi Kogyo Seiyaku Co., Ltd., carbonate-based urethane resin water-based emulsion, solid content concentration: 38.0%), elastic modulus at 23°C: 5.0 × 10 ⁶ Pa

(Silicone-based surfactant)
・ Silface SAG005 (manufactured by Nissin Chemical Industry Co., Ltd., polyether-modified silicone, effective content 100%)
(acetylenic surfactant)
- Surfynol 465 (manufactured by Nissin Chemical Industry Co., Ltd., ethylene oxide (EO) adduct of Surfynol 104 (2,4,7,9-tetramethyl-5-decyne-4,7-diol), EO average addition mole number: 10, effective content 100%)
・ Surfynol 420 (manufactured by Nissin Chemical Industry Co., Ltd., EO adduct of Surfynol 104, average number of moles of EO added: 1.3, effective content 100%)

Preparation Example 1 (Preparation of treatment liquid)
In a glass container, calcium nitrate tetrahydrate (manufactured by Fujifilm Wako Pharmaceutical Co., Ltd., solid content concentration: 100%) 8.0 parts, silicone surfactant (manufactured by Big Chemie Japan Co., Ltd., product name: BYK -348, effective content 100%) 0.1 part, styrene / acrylic emulsion (manufactured by Japan Coating Resin Co., Ltd., trade name: Movinyl 966A, solid content concentration: 45%) 5.6 parts, deionized water 86.3 and stirred with a magnetic stirrer for 10 minutes to obtain a treatment liquid containing a polyvalent metal salt.

<Preparation and Evaluation of Printed Material>
The treatment liquid containing the polyvalent metal salt obtained in Preparation Example 1 was evenly spray-coated in such an amount that the polyvalent metal salt was 1 g per A4 size fabric, and then placed in a constant temperature dryer at 150°C. After drying by heating for 1 minute and returning to room temperature of 23 ± 1 ° C., using the white ink compositions 1 to 3 and 11 to 14 obtained in Examples 1 to 3 and Comparative Examples 1 to 4, the following It was printed under the conditions and evaluated. Table 1 shows the results.
(1) Fabrication of printed material In an environment with a room temperature of 23 ± 1 ° C and a relative humidity of 50 ± 5%, the white circulation head of a textile printer (manufactured by Mastermind Co., Ltd., trade name: MMP8130, using color / white ink) Filled with white ink. Under the conditions of printing mode (black fabric, white ink base, printing speed 10 (1440 x 1800 dpi), unidirectional printing), fabric (manufactured by Toms Co., Ltd., Printstar Beeweight, 100% cotton, black T-shirt A4 size A solid image with a duty of 100% was printed on a sheet of paper (cutting to 100%) to prepare a printed product. The printed fabric thus obtained was immediately dried by heating in a constant temperature dryer at 150° C. for 3 minutes.

(2) Evaluation of texture Pinch two points of the obtained printed fabric with the index fingers and thumbs of both hands, and move both hands in opposite directions up and down, back and forth, and left and right to evaluate the texture of the fabric according to the following criteria. bottom.
(Evaluation criteria)
5: There is no change in the softness of the fabric before and after printing.
4: A very slight change in the softness of the fabric is observed before and after printing.
3: The fabric becomes slightly stiff before and after printing.
2: The fabric becomes hard before and after printing.
1: The fabric becomes very hard before and after printing.
If the evaluation criteria is 3 or more, there is no practical problem.

(3) Evaluation of Durability by Fingernail Rubbing The obtained printed matter was placed on a horizontal and smooth desk with the printed surface facing up, and the nail of the right thumb was applied to the printed surface at right angles to maintain a weight of 200 g. The skin was rubbed continuously from left to right while keeping it on. The number of times of rubbing when the ink on the printed fabric was visually peeled off was used as the criterion for evaluating durability.
If the number of times of resistance to fingernail rubbing until the ink is peeled off is 10 times or more, it is a level that can be practically used, but it is more desirable that it is 15 times or more.

From Table 1, the printed materials obtained using the white ink compositions obtained in Examples 1 to 3 are compared with the printed materials obtained using the white ink compositions of Comparative Examples 1 to 4. It can be seen that the texture and the durability against fingernail rubbing are well balanced.

Claims (11)

A white ink composition for inkjet textile printing containing a pigment, a fixing resin, and water,
the fixing resin includes a first fixing resin and a second fixing resin having different elastic moduli;
The elastic modulus of the first fixing resin at 23° C. is 1×10 ⁴ Pa or more and less than 1×10 ⁶ Pa, and the elastic modulus of the second fixing resin at 23° C. is 1×10 ⁶ Pa or more and 1×10. ⁸ Pa or less,
mass ratio of the first fixing resin to the total fixing resin is 0.2 or more and 0.8 or less;
A white ink composition for inkjet textile printing. 2. The white ink composition according to claim 1, wherein the first fixing resin contains a silicone group. 3. The white ink composition according to claim 2, wherein the first fixing resin has a silicone group content of 30% by mass or more and 80% by mass or less. 4. The white ink composition according to any one of claims 1 to 3, wherein the total fixing resin content in the white ink composition is 4% by mass or more and 18% by mass or less. 5. The white ink composition according to claim 1, wherein the fixing resin is contained in the white ink composition in an emulsion state. 6. The white ink composition according to any one of claims 1 to 5, wherein the pigment is titanium dioxide. a pigment, a first fixing resin having an elastic modulus of 1×10 ⁴ Pa or more and less than 1×10 ⁶ Pa at 23° C., a second fixing resin having an elastic modulus of 1×10 ⁶ Pa or more and 1×10 ⁸ Pa or less at 23° C. 7. The method for producing a white ink composition for inkjet textile printing according to any one of claims 1 to 6, comprising a step of mixing two fixing resins and water. An ink set for inkjet textile printing, comprising the white ink composition according to any one of claims 1 to 6 and a treatment liquid containing a polyvalent metal salt. 9. The ink set according to claim 8, comprising two or more inks having different hues. An inkjet textile printing method having the following steps 1 to 3.
Step 1: A step of applying a treatment liquid containing a polyvalent metal salt to a fabric to obtain a treated fabric Step 2: The white ink according to any one of Claims 1 to 6 is applied to the treated fabric obtained in Step 1. Step of applying the composition by an inkjet method to obtain a printed fabric Step 3: Step of drying the printed fabric obtained in Step 2 11. The textile printing method according to claim 10, comprising the following step 2' between steps 2 and 3.
Step 2': A step of printing color ink on the textile fabric obtained in step 2 by an inkjet method.