JP4045556B2 - Ink for inkjet recording - Google Patents

Description

Background of the Invention

FIELD OF THE INVENTION The present invention relates to an ink for ink jet recording capable of obtaining high print quality on various recording media and an ink jet recording method using the same.

Background Art Inkjet recording is a method of recording characters and figures on the surface of a recording medium by ejecting ink compositions as small droplets from fine nozzles. As an ink jet recording method, an electric signal is converted into a mechanical signal using an electrostrictive element, and an ink composition stored in a nozzle head portion is intermittently ejected to record characters and symbols on the surface of a recording medium. The ink composition stored in the nozzle head portion is rapidly heated at a location very close to the discharge portion to generate bubbles, and the characters and symbols are recorded on the surface of the recording medium by intermittent discharge due to volume expansion caused by the bubbles. Methods have been developed and put into practical use.

  Ink compositions used for such ink jet recording have good printing dryness, little printing blur, good printing on various recording media, and color mixing in the case of multicolor printing. Characteristics such as incompatibility are required.

  In particular, it is important to suppress bleeding to achieve a high-quality image. Paper is easy to bleed because it consists of various fibers with different permeability. In particular, since recycled paper is made of various types of fibers, the permeability of the fibers varies. Therefore, various proposals have been made to suppress the penetration of the ink composition into the recording medium or to improve the drying property in order to suppress bleeding.

  For example, use of glycol ether as a wetting agent as described in JP-B-2-2907, use of a water-soluble organic solvent as described in JP-B-1-15542, and description of JP-B-2-3837 As described above, the use of glycol ether as a dye dissolution accelerator is disclosed.

  Further, in order to improve the penetrability of the ink for ink jet recording, diethylene glycol monobutyl ether is added as described in US Pat. No. 5,156,675, and acetylene glycol-based surface activity is described as described in US Pat. No. 5,183,502. Adding Surfhinol 465 (manufactured by Nissin Chemical), or adding both diethylene glycol mono-n-butyl ether and Surfynol 465 as described in US Pat. No. 5,196,056, and further US Pat. The description in the specification of No. 2083372 discusses and teaches the use of ethers of diethylene glycol as the ink composition. Diethylene glycol mono-n-butyl ether is called by those skilled in the art under the name butyl carbitol, and is described in, for example, US Pat. No. 3,291,580.

  When a pigment is used as the ink composition, as a method for controlling the permeability of the ink composition, triethylene glycol monomethyl ether is used for the pigment as described in JP-A-56-147661, or JP-A-9 The use of ethylene glycol, diethylene glycol, or triethylene glycol ethers for the pigment as disclosed in JP-A-11111165 is disclosed.

  On the other hand, a method of printing an ink composition on a heated recording medium, evaporating the solvent component rapidly, and fixing the ink composition quickly has been proposed. May cause adverse effects. This method is also accompanied by the disadvantage of increased power consumption due to heating.

Summary of the Invention

  The present inventors have recently realized that an ink composition containing a compound having a specific structure can realize a good image with good drying property and less bleeding on various recording media, particularly recycled paper, by an inkjet recording method. Obtained knowledge.

  Accordingly, an object of the present invention is to provide an ink composition capable of realizing a good image on various recording media, particularly plain paper.

  The ink for ink jet recording according to the present invention contains at least a water-soluble coloring material, a water-soluble organic solvent, water, and a mixture of two or more compounds represented by the following formula (I). It will be.

［上記式中、
ＥＯはエチレンオキシ基を表し、
ＰＯはプロピレンオキシ基を表し、
Ｔは、ＯＨ基またはＳＯ_３Ｍを表し（ここで、Ｍは水素原子、アルカリ金属、無機塩基、または有機アミンを表す）、
ｍおよびｎは整数を表し、
ｋは１以上の自然数を表し、
ＲはＣ_ａＨ_{２ａ−ｋ−１}（ここで、ａは４〜１０の自然数を表す）を表すか、またはＲａ−Ｃ_ａＨ_{２ａ−ｋ−２}（ここで、ａは４〜１０の自然数を表す）を表し、ここでＲａは下記の基を表し：

（上記式中、ＥＯ、ＰＯ、Ｔ、およびｋは上記と同じ意味を表し、ｎ’およびｍ’は上記ｎおよびｍと同じ意味を表す）
ＥＯおよびＰＯは、［ ］内においてその順序は問わず、ランダムであってもブロックであってもよく、
ｎおよびｍならびにｎ’およびｍ’をインク組成物中に含まれる式（Ｉ）の化合物の混合物の平均値としてそれぞれ表した場合、ｎまたはｎ＋ｎ’は１〜１０の範囲にあり、ｍまたはｍ＋ｍ’は０〜５の範囲にある］

[In the above formula,
EO represents an ethyleneoxy group,
PO represents a propyleneoxy group,
T represents an OH group or SO ₃ M (where M represents a hydrogen atom, an alkali metal, an inorganic base, or an organic amine);
m and n represent integers;
k represents a natural number of 1 or more,
R represents C _a H _2a-k-1 (where a represents a natural number of 4 to 10), or Ra-C _a H _2a-k-2 (where a is a natural number of 4 to 10). Where Ra represents the following group:

(In the above formula, EO, PO, T, and k represent the same meaning as described above, and n ′ and m ′ represent the same meaning as n and m above)
EO and PO may be random or block in [] regardless of their order.
When n and m and n ′ and m ′ are expressed as average values of the mixture of the compounds of formula (I) contained in the ink composition, n or n + n ′ is in the range of 1 to 10, and m or m + m 'Is in the range of 0-5]

Detailed Description of the Invention

Ink for ink jet recording Ink for ink jet recording in the present invention means black ink for monochrome printing, and color ink for color printing, specifically yellow ink, magenta ink, and cyan. It shall mean ink, and possibly black ink.

Compound of Formula (I) The ink jet ink used in the present invention comprises a mixture of two or more compounds represented by the above formula (I).

In the formula (I), EO represents an O- ethyleneoxy i.e. _-CH 2 _CH 2, also PO is propyleneoxy i.e. _-CH 2 _CH 2 _CH 2 O- or _-CH (CH 3) represents a _CH 2 O-. The EO and PO are present in the molecule of the compound represented by the formula (I) (that is, in the brackets [] in the formula (I)), regardless of the order of existence, and may be random or block. Good.

M in S0 ₃ M represented by T represents a hydrogen atom, an alkali metal, an inorganic base, or an organic amine. Examples of the alkali metal include lithium, sodium, and potassium. Examples of the inorganic base include ammonia, and examples of the organic amine include mono-lower (preferably 1 to 6 carbon) alkylamines and di-lower (preferably 1 to 6 carbon) alkylamines. Examples include monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, and mono-s-butanolamine.

C _a H _2a-k-1 represented by R in the formula (I) may be branched or linear. Here, a represents a natural number of 4 to 10. K represents the number of-[(EO) n- (PO) m]-groups bonded to R. Thus, for example, when k = 1, R represents a C _4-10 alkyl group. Specific examples thereof include butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group and decyl group. By being an alkyl group having 4 to 10 carbon atoms, an ink composition having good permeability can be obtained. As described above, this alkyl group may be a branched chain or a straight chain, but a branched chain is generally preferred. For example, in the case of a butyl group, by using a compound having a branched structure of isobutyl group or t-butyl group as a main component, an ink composition having good penetrability can be obtained, and a good quality image can be obtained. In the present invention, the compound of the formula (I) is used as a mixture.

  In the formula (I), k represents a natural number of 1 or more, but is preferably about 1 to 4. That is, the compound of the formula (I) can be obtained by reacting an alcohol with ethylene oxide or propylene oxide as described later. However, when an alcohol containing one OH group is used, k is 1, and the OH group is 2, 3, And k are 2, 3 and 4, respectively, when four or four glycols, triols and tetraols are used. Further, there may be an OH group that does not react with ethylene oxide or propylene oxide. In the present invention, the compound of the formula (I) having such an unreacted OH group is also included in the scope of the present invention. It is.

R represents Ra—C _a H _2a-k-2 , which may be a branched chain or a straight chain. Ra represents the following group.

上記式中、ＥＯ、ＰＯ、およびＴ上記と同じ意味を表し、ｎ’およびｍ’は上記ｎおよびｍと同じ意味を表す。従って、ＥＯおよびＰＯは、［ ］内においてその順序は問わず、ランダムであってもブロックであってもよい。

In the above formula, EO, PO, and T represent the same meaning as described above, and n ′ and m ′ represent the same meaning as n and m described above. Therefore, the order of EO and PO is not limited in [], and may be random or block.

  In the present invention, n and m and n ′ and m ′ are expressed as an average value of a mixture of compounds of formula (I) contained in the ink composition, and n or n + n ′ is in the range of 1 to 10, m or m + m ′ is in the range of 0-5. By setting n and m, and n 'and m' within the above ranges, an ink composition having good permeability and less foaming can be obtained, and a good quality image can be obtained. According to a preferred embodiment of the present invention, it is preferred that n and m in the mixture of compounds of formula (I) satisfy n / m ≧ 0.5.

  The molecular weight of the compound of the formula (I) may be appropriately determined, but the average molecular weight is preferably 2000 or less.

According to a first preferred embodiment of the invention, the mixture of compounds of formula (I) is a mixture of compounds of formula (I) in which R represents C _a H _2a-k-1 and T represents a hydrogen atom. Use is preferred.

According to a second preferred embodiment of the invention, the mixture of compounds of formula (I) is a mixture of compounds of formula (I) in which R represents Ra—C _a H _2a-k-2 and T represents a hydrogen atom. Use is preferred.

According to a third preferred embodiment of the invention, as a mixture of compounds of formula (I), compounds of formula (I) in which R represents a C _a H _2a-k-2 alkyl group and T represents SO ₃ M The use of a mixture of

According to a fourth preferred embodiment of the invention, as a mixture of compounds of formula (I), R represents C _a H _2a-k-1 , EO represents —CH ₂ CH ₂ O—, and PO represents — Use of a mixture of compounds of formula (I), which represents CH (CH ₃ ) —CH ₂ O—, T represents a hydrogen atom, and is bonded in the order of R— (EO) n — (PO) m —T Is preferred.

According to a fifth preferred embodiment of the invention, as a mixture of compounds of formula (I)
A compound of the formula (I) in which R represents C _a H _2a-k-1 , T represents a hydrogen atom and R— (EO) n — (PO) m —T is bonded in this order;
R is a compound of the formula (I) in which R represents C _a H _2a-k-1 , T represents a hydrogen atom, and R— (PO) m— (EO) n—T is bonded in this order. The use of a mixture is preferred.

  The compound of the formula (I) can be obtained by adding a target molar amount of ethylene oxide or propylene oxide under an atmosphere such as an alkali using an alcohol having a corresponding structure as a starting material. The compound of formula (I) thus obtained is generally a mixture of two or more compounds represented by formula (I).

  Further, it is desirable that the alcohol used in the production does not remain, and even if it remains, it is preferably 1% by weight or less. This is because if it is 1% by weight or less, wetting on the nozzle surface of the head will occur and printing will not easily deteriorate, and problems such as the generation of alcohol odor will not occur.

(Di) Propylene glycol monobutyl ether According to a preferred embodiment of the present invention, the ink composition according to the present invention preferably comprises (di) propylene glycol monobutyl ether. By containing (di) propylene glycol monobutyl ether, an ink composition having higher permeability can be obtained. The amount added may be appropriately determined within a range in which the permeability effect is obtained, but is preferably about 0 to 10% by weight, more preferably 0.5 to 5% by weight.

  Furthermore, according to the preferable aspect of this invention, it is preferable to add in the range whose weight ratio of the compound of the said formula (I) and (di) propylene glycol monobutyl ether is 1: 0 to 1:10.

Acetylene glycol surfactants According to a preferred embodiment of the present invention, the ink composition according to the present invention preferably comprises an acetylene glycol surfactant. By adding an acetylene glycol-based surfactant, an ink composition that realizes an image with even better print quality can be obtained. The amount of addition may be appropriately determined, but is preferably about 5% by weight or less, more preferably about 0.1 to 2% by weight.

  Furthermore, according to the preferable aspect of this invention, it is preferable to add in the range whose weight ratio of the compound of the said formula (I) and acetylene glycol surfactant is 1: 0 to 1: 3.

  Commercially available products may be used as the acetylene glycol surfactant, and for example, Surfynol 465, TG, 104 (Air Products) and their modified products may be added.

Di (tri) ethylene glycol monobutyl ether According to a preferred embodiment of the present invention, the ink composition according to the present invention preferably comprises di (tri) ethylene glycol monobutyl ether. By adding di (tri) ethylene glycol monobutyl ether, it is possible to obtain an ink composition that realizes an image with even better print quality. The amount added may be appropriately determined, but is preferably about 20% by weight or less.

  Furthermore, according to the preferable aspect of this invention, it is preferable to add in the range whose weight ratio of the compound of the said formula (I) and di (tri) ethylene glycol monobutyl ether is 1: 0 to 1:10.

Colorant The colorant contained in the ink of the present invention may be either a dye or a pigment.

  As the dye, various dyes used for inkjet recording such as direct dyes, acid dyes, food dyes, basic dyes, reactive dyes, disperse dyes, vat dyes, soluble vat dyes, reactive disperse dyes, etc. may be used. it can.

  As the pigment, inorganic pigments and organic pigments can be used without any particular limitation. As the inorganic pigment, in addition to titanium oxide and iron oxide, carbon black produced by a known method such as a contact method, a furnace method, or a thermal method can be used. Organic pigments include azo pigments (including azo lakes, insoluble azo pigments, condensed azo pigments, chelate azo pigments), polycyclic pigments (for example, phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazines). Pigments, thioindigo pigments, isoindolinone pigments, quinofullerone pigments, etc.), dye chelates (for example, basic dye chelate, acid dye chelate, etc.), nitro pigments, nitroso pigments, aniline black, and the like.

  The pigment preferably used in the present invention is a surface treatment in which at least one functional group of a carbonyl group, a carboxyl group, a hydroxyl group, or a sulfone group or a salt thereof is bonded to the surface of the pigment without adding a dispersant. It can be dispersed and / or dissolved. Specifically, it can be obtained by grafting a functional group or a molecule containing a functional group onto the surface of carbon black by physical treatment or chemical treatment such as vacuum plasma. In the present invention, the functional group grafted on one carbon black particle may be single or plural. The type and degree of the functional group to be grafted may be appropriately determined in consideration of dispersion stability in the ink composition, color density, drying property on the front surface of the inkjet head, and the like.

  In the present invention, a state where the pigment is stably present in water without a dispersant is expressed as “dispersion and / or dissolution”. In many cases, it is difficult to clearly distinguish whether a substance is dissolved or dispersed. In the present invention, as long as it is a pigment that can exist stably in water without a dispersant, such a pigment can be used regardless of whether the state is dispersed or dissolved. Therefore, in the present specification, a pigment that can exist stably in water without a dispersant is sometimes referred to as a water-soluble pigment, but it does not mean that even a pigment in a dispersed state is excluded.

  According to a preferred embodiment of the present invention, it is preferably used as a pigment dispersion having an average particle size of 50 to 200 nm and a dispersity of 10 or less.

  The pigment preferably used in the present invention can be obtained, for example, by the method described in JP-A-8-3498. Moreover, a commercial item can also be utilized as the pigment, and a preferred example is Microjet CW1 manufactured by Orient Chemical Industries.

  The amount of the pigment added to the ink composition is preferably 3 to 30% by weight, more preferably about 5 to 17% by weight.

Examples of water-soluble organic solvent contained in the ink composition of the water-soluble organic solvent present invention, ethanol, methanol, butanol, propanol, alkyl alcohols from C 1 to 4 carbon atoms such as isopropanol, ethylene glycol monomethyl ether, ethylene glycol Monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-propyl ether, ethylene glycol mono-iso-propyl ether, diethylene glycol mono-iso-propyl ether, ethylene Glycol mono-n-butyl ether, diethylene glycol mono-n-butyl ether Triethylene glycol mono-n-butyl ether, ethylene glycol mono-t-butyl ether, diethylene glycol mono-t-butyl ether, 1-methyl-1-methoxybutanol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-t- Butyl ether, propylene glycol mono-n-propyl ether, propylene glycol mono-iso-propyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol mono-n-propyl ether, dipropylene glycol mono-iso- Propyl ether, propylene glycol mono-n-butyl ether, dipropylene glycol mono-n Glycol ethers such as butyl ether, formamide, acetamide, dimethyl sulfoxide, sorbitol, sorbitan, acetin, diacetin, triacetin, and sulfolane.

  The amount of the aqueous organic solvent added to the ink composition is preferably 1 to 30% by weight, more preferably about 3 to 15% by weight.

Water and other components In the ink composition according to the present invention, water is a main solvent. As the water, pure water such as ion exchange water, ultrafiltration water, reverse osmosis water, distilled water, or ultrapure water can be used. In addition, the use of water sterilized by ultraviolet irradiation or addition of hydrogen peroxide is preferable because generation of mold and bacteria can be prevented when the ink composition is stored for a long period of time.

  According to a preferred embodiment of the present invention, it is preferable to add water-soluble glycols to the ink. Preferable examples of water-soluble glycols include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, polyethylene glycol having a molecular weight of 2000 or less, 1,3-propylene glycol, isopropylene glycol, isobutylene. There are glycol, 1,4-butanediol, 1,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, glycerin, mesoerythritol, pentaerythritol and the like. Water-soluble glycols have an effect of suppressing drying of the ink in front of the nozzles.

  The amount of glycols added to the ink composition is preferably 1 to 30% by weight, more preferably about 3 to 15% by weight.

  According to a preferred embodiment of the present invention, many types of saccharides can be used in the ink. Preferable examples of saccharides to be used include monosaccharides and polysaccharides. More specifically, glucose, mannose, fructose, ribose, xylose, arabinose, lactose, galactose, aldonic acid, glucitolose, maltose, cellobiose, sucrose, trehalose, malto In addition to triose, there are alginic acid and its salts, cyclodextrins, celluloses and the like. The amount of saccharide added to the ink is preferably about 0.05% to 30%.

  By adding saccharides, it is possible to avoid the clogging phenomenon that the ink is dried and clogged at the tip of the head. Note that. In the above examples, the addition amount of monosaccharides and polysaccharides, which are general saccharides, to the ink is preferably about 3 to 20%. In the above examples, the addition amount of alginic acid and its salts, cyclodextrins, and celluloses to the ink must be such that the low viscosity of the ink is maintained and proper printing can be performed.

  According to a preferred embodiment of the present invention, the ink composition can comprise a surfactant. The surfactant is preferably one having good compatibility with the other components of the ink composition, and among the surfactants, one having high permeability and stability is preferable. Preferable examples include amphoteric surfactants and nonionic surfactants. Examples of amphoteric surfactants include lauryldimethylaminoacetic acid betaine, 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, coconut oil fatty acid amidopropyldimethylaminoacetic acid betaine, polyoctylpolyaminoethylglycine and other imidazoline derivatives. Etc. Nonionic surfactants include, for example, polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene dodecyl phenyl ether, polyoxyethylene alkyl allyl ether, polyoxyethylene oleyl ether, polyoxyethylene lauryl ether, polyoxyethylene lauryl ether, Ethers such as oxyethylene alkyl ether and polyoxyalkylene alkyl ether, polyoxyethylene oleic acid, polyoxyethylene oleate, polyoxyethylene distearate, sorbitan laurate, sorbitan monostearate, sorbitan monooleate, sorbitan Esters such as sesquioleate, polyoxyethylene monooleate, polyoxyethylene stearate, Fluoroalkyl esters, such as fluorine-containing surfactants such as perfluoroalkyl carboxylate are exemplified.

  The amount of the surfactant added to the ink composition is preferably 0.01 to 5% by weight, more preferably about 0.1 to 3% by weight.

  According to a preferred embodiment of the present invention, when the colorant according to the present invention is a pigment, it is preferable that the ink further comprises an emulsion. By adding this emulsion, it is possible to improve the fixability and abrasion resistance of the print. This emulsion is preferably such that the continuous phase is water and the dispersed phase is an acrylic resin, methacrylic acid resin, styrene resin, urethane resin, acrylamide resin, epoxy resin, or a mixed form thereof. In particular, the dispersed phase is preferably made of a resin mainly composed of acrylic acid and / or methacrylic acid. These resins are not limited depending on the mode of copolymerization, and can be, for example, block copolymers, random copolymers, and the like. Furthermore, the emulsion used in the ink according to the present invention has a film-forming ability, and preferably has a minimum film-forming temperature of room temperature or lower, more preferably a temperature of 0 ° C. or higher and 20 ° C. or lower.

  According to a preferred embodiment of the present invention, the resin component of the emulsion is preferably a core-shell type resin particle comprising a core portion and a shell portion surrounding the core portion. For example, it is possible to adopt a configuration in which a resin component that can improve the finger touch and fixability of the ink is introduced into the core portion, and a resin component that causes the resin particles to stably exist in the ink is introduced into the shell portion. According to a preferred embodiment of the present invention, the shell part is preferably made of a resin having a crosslinked structure or a structure having more benzene nuclei than the core part.

  Examples of the substance forming the shell part include styrene, tetrahydrofurfuryl acrylate, butyl methacrylate, (α, 2, 3 or 4) -alkyl styrene, (α, 2, 3 or 4) -alkoxy styrene, 3,4-dimethyl. Styrene, α-phenylstyrene, divinylbenzene, vinylnaphthalene, dimethylamino (meth) acrylate, dimethylaminoethyl (meth) acrylate, dimethylaminopropylacrylamide, N, N-dimethylaminoethyl acrylate, acrylomorpholine, N, N -Dimethylacrylamide, N-isopropylacrylamide, N, N-diethylacrylamide, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, ethylhexyl (meth) acrylate Other alkyl (meth) acrylates, methoxydiethylene glycol (meth) acrylate, ethyl ester of diethylene glycol or polyethylene glycol, (meth) acrylate of propyl ester or butyl ester, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, phenoxyethyl (meth) ) Acrylate, isobornyl (meth) acrylate, hydroxyalkyl (meth) acrylate, fluorine-containing, chlorine-containing, silicon-containing (meth) acrylate, (meth) acrylamide, maleic acid amide and the like.

  In addition to the above (meth) acrylic acid, when a crosslinked structure is introduced, (mono, di, tri, tetra, poly) ethylene glycol di (meth) acrylate, 1,4-butanediol, 1,5-pentanediol , 1,6-hexanediol, 1,8-octanediol and 1,10-decanediol, etc. (meth) acrylate, trimethylolpropane tri (meth) acrylate, glycerin (di, tri) (meth) acrylate, bisphenol A Alternatively, di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, or the like of ethylene oxide adduct of F can be used.

  In the formation of the core part, the above-mentioned substance forming the shell part can be used.

  As the emulsifier used for forming such polymer fine particles, conventionally used sodium lauryl sulfate, potassium lauryl sulfate, an anionic surfactant, a nonionic surfactant, and an amphoteric surfactant can be used.

  As polymerization initiators, potassium persulfate, ammonium persulfate, hydrogen persulfate, azobisisobutyronitrile, benzoyl peroxide, dibutyl peroxide, peracetic acid, cumene hydroperoxide, t-butylhydroxyperoxide, paramentanehydroxy Peroxide can be used.

  Examples of chain transfer agents for polymerization include t-dodecyl mercaptan, n-dodecyl mercaptan, n-octyl mercaptan, xanthogens dimethylxanthogen disulfide, diisobutylxanthogen disulfide, dipentene, indene, 1,4-cyclohexadiene, dihydrofuran. , Xanthene and the like can be used.

  According to a preferred embodiment of the present invention, the molecular weight of the emulsion is preferably 1000 or more, more preferably about 10,000 to 100,000.

  Commercially available products can also be used as the emulsion used in the present invention, and examples thereof include Z116 manufactured by Mitsui Toatsu.

  Although the addition amount of this emulsion may be determined suitably, for example, about 0.5 to 10 weight% is preferable, More preferably, it is about 3 to 5 weight%.

  The ink composition according to the present invention includes preservatives, antioxidants, ultraviolet absorbers, conductivity adjusters, pH adjusters, viscosity adjusters, surface tension adjusters, oxygen absorbers, nozzle eyes as components other than those described above. It may further contain a clogging preventing agent or the like.

  In the present invention, the ink contains sodium benzoate, sodium pentachlorophenol, sodium 2-pyridinethiol-1-oxide, sodium sorbate, sodium dehydroacetate, 1,2-dibenzothiazoline as a preservative or fungicide. 3-one (Proxel CRL, Proxel BDN, Proxel GXL, Proxel XL-2, Proxel TN from ICI) and the like can be used.

  Inorganic amines such as diethanolamine, triethanolamine, propanolamine, morpholine and their modified products, potassium hydroxide, sodium hydroxide, lithium hydroxide and the like as pH adjusters, dissolution aids, or antioxidants in the ink , Ammonium hydroxide, quaternary ammonium hydroxide (tetramethylammonium, etc.), carbonates such as potassium carbonate, sodium carbonate, lithium carbonate and other phosphates, or N-methyl-2-pyrrolidone, urea, thiourea, tetra L-ascorbic acid and salts thereof, such as ureas such as methylurea, allophanates such as allophanate and methylallohanate, biurets such as biuret, dimethylbiuret, and tetramethylbiuret can be used.

  Examples of antioxidants and UV absorbers include Ciba Geigy's Tinuvin 328, 900, 1130, 384, 292, 123, 144, 622, 770, 292, Irgacor 252, 153, Irganox 1010, 1076, 1035, MD1024, or lanthanide oxidation Such as things.

  As the viscosity modifier, rosins, alginic acids, polyvinyl alcohol, hydroxypropyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose, polyacrylate, polyvinyl pyrrolidone, gum arabic starch and the like can be used.

Inkjet recording method and apparatus The inkjet recording method in which the ink composition according to the present invention is used means a recording method in which droplets of the ink composition are ejected and the droplets are attached to a recording medium for printing. As an example of such an ink jet recording method, for example, an electrostrictive element is used to convert an electrical signal into a mechanical signal, and ink stored in the nozzle head portion is intermittently ejected to write characters and symbols on the surface of the recording medium. The ink stored in the nozzle head part is rapidly heated at a location very close to the discharge part to generate bubbles, and the characters and symbols are recorded on the surface of the recording medium by intermittently discharging with the volume expansion caused by the bubbles. The method of recording is mentioned. According to a preferred embodiment of the present invention, the ink composition according to the present invention is preferably used in an ink jet recording method using an electrostrictive element. This is because, in the method of heating the head portion, the colorant and other components contained in the ink are decomposed and the head may be easily clogged.

  In the case of an ink having a relatively large amount of solid matter that can contain a pigment as a colorant, such as the ink according to the present invention, a nozzle that does not discharge for a long time tends to be thickened due to drying of the ink on the front surface of the nozzle, and printing is likely to be disturbed. Therefore, by finely moving the ink so as not to be ejected from the front surface of the nozzle, the ink is stirred and the ink can be ejected stably. The fine movement method can be generated by controlling the pressurizing means for ejecting ink so as not to eject ink. When performing such control, it is preferable to use an electrostrictive element as the pressurizing means because of the ease of control. Also, by using this mechanism, the pigment concentration in the ink can be increased, so that the color density of the pigment ink is high and the ink can be ejected stably.

  Further, when the fine movement is performed on the nozzle surface in the ink jet recording apparatus, it is effective for an ink composition having a pigment content of about 5% to 15% by weight, more preferably about 7% to 10% by weight. Ink composition.

  In addition, the ink composition according to the present invention may be used by being filled in an ink tank filled with polyurethane foam and having a structure in which the ink and urethane foam are in contact with each other. In this case, glycol ethers and acetylene glycol surfactants that are preferably used in the present invention are adsorbed to the urethane foam. Therefore, it is preferable to add excessively in consideration of the adsorbed amount. In addition, the urethane foam can secure a negative pressure by using the ink composition according to the present invention, and further, the urethane foam is decomposed by each component of the ink used in the present invention and causes foreign matters to cause clogging. Less is. The urethane foam curing catalyst does not use metal salts or cationic ones, but includes polyfunctional isocyanates such as tolylene diisocyanate and metaxylylene diisocyanate and glycols such as polypropylene glycol and polyethylene glycol having an average molecular weight of about 300 to 3000. A urethane foam comprising a substance having a plurality of hydroxy groups, such as glycerin, pentaerythritol, dipentaerythritol, neopentyl glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol. It is preferable to use it from the viewpoint of securing a negative pressure due to the stability of the foam shape and chemical stability.

  When an acetylene glycol surfactant is used, the polyurethane foam adsorbs a part of the acetylene glycol surfactant. Therefore, when adding an acetylene glycol surfactant to the ink composition, it should be noted that it is necessary to determine the composition of the ink composition in consideration of the amount adsorbed on the urethane foam.

  Furthermore, according to a preferred aspect of the present invention, it is preferable that the ink composition according to the present invention is printed using a nozzle having a tip of a water-repellent surface as a nozzle for ejecting ink droplets. More specifically, the nozzle tip has a structure in which a stainless steel material is used as a base material, a eutectoid plating of tetrafluoroethylene and nickel is performed thereon, and a water repellent layer is formed by heat treatment. preferable. Further, it is also preferable to use eutectoid plating with a metal having high oxidation resistance such as chromium, titanium, gold, platinum, silver, iridium instead of nickel. By combining the ink composition according to the present invention and such nozzles, continuous printing stable for a long period of time can be realized.

  According to a more preferred aspect of the present invention, the contact angle of the nozzle tip of the ink composition with the water-repellent surface is 50 ° or more at a normal printer operating temperature (for example, 15 ° C. to 60 ° C.). preferable. According to this aspect, the print quality can be improved and continuous printing can be performed.

  In the following description, the following abbreviations are used.

DEGmBE: Diethylene glycol mono-n-butyl ether DMI: 1,3-dimethyl-2-imidazolidinone PGmBE: Propylene glycol mono-n-butyl ether MPD: 2-methyl-2,4-pentanediol DPGmBE: Dipropylene glycol mono- n-butyl ether TEGmBE: triethylene glycol mono-n-butyl ether In the following, the values of n, m, n ′, and m ′ are average values based on the weight of the compound of formula (I) present in the system. .

Preparation of polymer fine particles Polymer fine particles A to D used in the following examples were prepared as follows.

Polymer fine particles A
In a reaction vessel equipped with a dropping device, a thermometer, a water-cooled reflux condenser, and a stirrer, 100 parts of ion-exchanged water is added, and a superficial acid potassium as a polymerization initiator is 0.2 in a nitrogen atmosphere at 70 ° C. with stirring. Parts were added. A monomer solution was prepared by adding 0.05 part of sodium lauryl sulfate, 5 parts of styrene, 6 parts of tetrahydrofurfuryl acrylate, 5 parts of butyl methacrylate, and 0.02 of t-dodecyl mercaptan to 7 parts of ion-exchanged water. Was added dropwise to a reaction vessel at 70 ° C. to cause a reaction to produce a primary substance. To this primary substance, 2 parts of a 10% ammonium persulfate solution was added and stirred, and further 30 parts of ion exchange water, 0.2 part of potassium lauryl sulfate, 30 parts of styrene, 15 parts of butyl methacrylate, 16 parts of butyl acrylate. Then, a reaction solution consisting of 2 parts of acrylic acid, 1 part of 1,6-hexanediol dimethacrylate, and 0.5 part of t-dodecyl mercaptan was added at 70 ° C. with stirring to cause polymerization reaction. Then, it neutralized with ammonia, it was set as pH 8-8.5, and it filtered with the filter of 0.3 micrometer, and obtained the polymer fine particle A as an emulsion.

Polymer fine particle B
In a reaction vessel equipped with a dropping device, a thermometer, a water-cooled reflux condenser, and a stirrer, 100 parts of ion-exchanged water is added, and a superficial acid potassium as a polymerization initiator is 0.2 in a nitrogen atmosphere at 70 ° C. with stirring. Parts were added. A monomer solution was prepared by adding 0.05 part of sodium lauryl sulfate, 10 parts of styrene, 10 parts of butyl methacrylate, and 0.02 part of t-dodecyl mercaptan to 7 parts of ion-exchanged water. The primary material was prepared by adding dropwise and reacting. To this primary substance, 2 parts of 10% ammonium persulfate solution was added and stirred, and further 30 parts of ion exchange water, 0.2 part of potassium lauryl sulfate, 35 parts of styrene, 25 parts of butyl methacrylate, 10 parts of acrylic acid. Then, a reaction solution consisting of 1 part of bisphenol A dimethacrylate and 0.5 part of t-dodecyl mercaptan was added with stirring at 70 ° C. to cause polymerization reaction. Then, it neutralized with ammonia, it was set to pH 8-8.5, and it filtered with the 0.3 micrometer filter, and obtained the polymer microparticles | fine-particles B as an emulsion.

Polymer fine particle C
In a reaction vessel equipped with a dropping device, a thermometer, a water-cooled reflux condenser, and a stirrer, 100 parts of ion-exchanged water is added, and a superficial acid potassium as a polymerization initiator is 0.2 in a nitrogen atmosphere at 70 ° C. with stirring. Parts were added. A monomer solution was prepared by adding 0.05 part of sodium lauryl sulfate, 15 parts of styrene, 6 parts of benzyl methacrylate, 10 parts of butyl methacrylate, and 0.02 part of t-dodecyl mercaptan to 7 parts of ion-exchanged water. A primary substance was prepared by adding dropwise a reaction to the reaction vessel at 70 ° C. for reaction. To this primary material, 2 parts of a 10% ammonium persulfate solution was added and stirred. Further, 30 parts of ion exchange water, 0.2 part of potassium lauryl sulfate, 30 parts of styrene, 15 parts of butyl methacrylate, 10 parts of acrylic acid. A reaction solution consisting of 1 part of triethanolpropane trimethacrylate, 1 part of 1,6-hexanediol dimethacrylate and 0.5 part of t-dodecyl mercaptan was added at 70 ° C. with stirring to cause polymerization reaction. Then, it neutralized with ammonia, it was set as pH 8-8.5, and it filtered with the filter of 0.3 micrometer, and obtained the polymer fine particle C as the emulsion C.

Polymer fine particle D
In a reaction vessel equipped with a dropping device, a thermometer, a water-cooled reflux condenser, and a stirrer, 100 parts of ion-exchanged water is added, and a superficial acid potassium as a polymerization initiator is 0.2 in a nitrogen atmosphere at 70 ° C. with stirring. Parts were added. A monomer solution was prepared by adding 0.05 part of sodium lauryl sulfate, 15 parts of styrene, 15 parts of butyl methacrylate and 0.02 part of t-dodecyl mercaptan to 7 parts of ion-exchanged water. The primary material was prepared by adding dropwise and reacting. To this primary substance, 2 parts of a 10% ammonium persulfate solution was added and stirred. Further, 30 parts of ion exchange water, 0.2 part of potassium lauryl sulfate, 30 parts of styrene, 15 parts of butyl methacrylate, dipentaerythritol hexa A reaction solution consisting of 1 part of methacrylate and 0.6 part of t-dodecyl mercaptan was added at 70 ° C. with stirring to cause polymerization reaction. Then, it neutralized with ammonia, it was set to pH 8-8.5, and it filtered with the filter of 0.3 micrometer, and obtained the polymer fine particle D as an emulsion.

Example A
Preparation of ink composition Water-soluble pigments 1 to 4 in the following examples have a carbonyl group, a carboxyl group, a hydroxyl group, and / or a sulfone group at the terminal by oxidation treatment on the surface of carbon black having a particle size of 10 to 300 nm. It means a water-soluble pigment having a group. Further, the average particle diameter of the water-soluble pigment was as indicated by the unit of nm in parentheses.

  In addition, the compound of the formula (I) used in the following Example A is a compound in which T is a hydrogen atom.

  In the following, the water-soluble dye 1 is direct black 154, the water-soluble dye 2 is direct yellow 132, the water-soluble dye 3 is direct blue 86, and the water-soluble dye 4 is acid red 52.

  In addition, all of the following ink compositions contain 0.1 to 1% by weight of Proxel XL-2 to prevent ink corrosion and 0.001 to 0.05% by weight of benzotriazole to prevent corrosion of ink jet head members. % Was added.

Example A1 addition amount (% by weight)
Water-soluble pigment 1 (105) 5.0
Compound A1 of Formula (I) 8.0
DEGmBE 2.0
Polymer fine particles A 3.0
Glycerin 6.0
1,5-pentanediol 5.0
Triethanolamine 0.8
Residual amount of ion-exchanged water The compound A1 of the formula (I) is a compound of the formula (I) in which R is a neopentyl group, n is 3, and m is 1.5.

Example A2
Water-soluble pigment 2 (85) 4.5
Compound A2 of Formula (I) 10.0
Polymer fine particles A 3.0
Dipropylene glycol 5.0
Surfinol 465 1.2
Triethanolamine 0.9
Residual amount of ion-exchanged water Compound A2 of formula (I) is a compound of formula (I) in which R is a t-butyl group, n is 3, and m is 1.3.

Example A3
Water-soluble pigment 3 (90) 5.5
Compound A3 of formula (I) 10.0
Polymer fine particle B 10.0
Diethylene glycol 7.0
Thiodiglycol 3.5
1,6-hexanediol 5.0
Triethanolamine 1.0
Potassium hydroxide 0.1
Residual amount of ion-exchanged water The compound A3 of the formula (I) is a compound of the formula (I) in which R is a 1,3-dimethylbutyl group, n is 3, and m is 1.5.

Example A4
Water-soluble pigment 4 (80) 5.0
Water-soluble dye 1 1.0
Compound A4 of formula (I) 8.0
TEGmBE 3.0
Polymer fine particle C 1.0
Diethylene glycol 3.0
1,5-pentanediol 2.0
Dimethyl-2-imidazolidinone 2.0
Sodium benzoate 0.1
Triethanolamine 0.7
Residual amount of ion-exchanged water The compound A4 of the formula (I) is a compound of the formula (I) in which R is an isobutyl group, n is 3, and m is 0.5.

Example A5
Water-soluble pigment 1 (105) 3.0
Water-soluble dye 1 1.0
Compound A5 of formula (I) 7.0
DEGmBE 2.0
Polymer fine particle D 1.0
Glycerol 14.0
Triethanolamine 0.9
Residual amount of ion-exchanged water Compound A5 of the formula (I) is prepared by mixing 50% by weight of the compound of the formula (I) in which R is an n-hexyl group, n is 4, and m is 2, and R is 2-ethylhexyl. A mixture of 50% by weight of a compound of the formula (I) in which n is 4 and m is 0.

Example A6
Water-soluble dye 2 5.0
Compound A6 of formula (I) 6.0
TEGmBE 4.0
Glycerin 15.0
Thiodiglycol 2.0
1,5-pentanediol 1.0
Triethanolamine 0.9
Residual amount of ion-exchanged water The compound A6 of the formula (I) is a compound of the formula (I) in which R is a 1,1-dimethylbutyl group, n is 4, and m is 1.

Example A7
Water-soluble dye 3 5.0
Compound A7 of formula (I) 10.0
DEGmBE 3.0
Glycerin 5.0
Trimethylolpropane 1.0
Trimethylolethane 1.0
Surfinol 465 1.0
Triethanolamine 0.5
KOH 0.05
Remaining amount of ion-exchanged water Compound A7 of the formula (I) has a compound in which R is 1,3-dimethylbutyl, n is 3, m is 1, and 50% by weight of the compound of the formula (I), R is A mixture with 50% by weight of a compound of formula (I) which is an n-heptyl group, n is 3.5 and m is 1.

Example A8
Water-soluble dye 4 5.5
Compound A8 of formula (I) 6.0
Glycerin 5.0
Diethylene glycol 5.0
Tetrapropylene glycol 5.0
Triethanolamine 0.9
KOH 0.1
Remaining amount of ion-exchanged water In the compound A8 of the formula (I), R is a neopentyl group, n is 1.0, m is 0.3, and 50% by weight of the compound of the formula (I), and R is n -30% by weight of the compound of formula (I), which is a pentyl group, n is 2.5 and m is 1.0, R is an isopentyl group, n is 3.0 and m is 1 A mixture with 20% by weight of a compound of the formula (I) which is .5.

Comparative Example A
In the following comparative examples, the water-soluble pigment means carbon black dispersed using a random copolymer styrene acrylic acid dispersant, and the average particle size is shown in parentheses in parentheses. It was as it was.

Comparative Example 1
Water-soluble pigment 9 (90) 5.0
Glycerin 10.0
Dispersant 3.0
Nonionic surfactant 1.0
Ion exchange water

Comparative Example 2
Water-soluble dye (food black 2) 5.5
DEGmME 7.0
Diethylene glycol 10.0
2-pyrrolidone 5.0
Ion exchange water

Comparative Example 3
Water-soluble pigment 11 (110) 5.5
Water-soluble dye (Food Black 2) 2.5
Diethylene glycol 10.0
Nonionic surfactant 1.0
Ion exchange water

Printing Evaluation Test Characters were printed using the ink compositions of Examples A1 to 8 and Comparative Examples A1 to A3 described above using an inkjet printer-MJ-930C (manufactured by Seiko Epson Corporation). The paper used for the evaluation is plain paper commercially available in Europe, the United States, and Japan, Conqueror paper, Favorit paper, Modo Copy paper, Rapid Copy paper, EPSON EPP paper, Xerox 4024 paper, Xerox 10 paper, Neenha. Bond paper, Rcopy 6200 paper, Yamayuri paper, and Xerox R paper.

  The degree of bleeding of the obtained printed matter was evaluated according to the following criteria.

  The evaluation is based on the assumption that a spherical ink droplet of 10 to 50 mg spreads in a circle on the paper surface, and the ratio r2 / r of the radius r1 of the inscribed circle and the radius r2 of the circumscribed circle formed by the ink droplet. The value of r1 was compared. The results were evaluated according to the following criteria.

Evaluation A: r2 / r1 ≦ 2.0
Evaluation B: 2.0 <r2 / r1 ≦ 4.0
Evaluation C: 4.0 <r2 / r1 ≦ 6.0
Evaluation D: 6.0 <r2 / r1
The results were as shown in the table below.

Example B
The water-soluble pigments 1 to 4 in the following examples are water-soluble pigments having a group having a carbonyl group, a carboxyl group, a hydroxyl group, or a sulfone group at the terminal by oxidation treatment on the surface of carbon black having a particle size of 10 to 300 nm. Means. Further, the average particle diameter of the water-soluble pigment was as indicated by the unit of nm in parentheses.

  The compound of formula (I) used in the following Example B is a compound in which T is a hydrogen atom.

  In the following, the water-soluble dye 1 is direct black 154, the water-soluble dye 2 is direct yellow 132, the water-soluble dye 3 is direct blue 86, and the water-soluble dye 4 is acid red 52.

  In addition, 0.1 to 1% of Proxel XL-2 is added to all of the ink compositions below, and 0.001 to 0.05% of benzotriazole is added to prevent corrosion of the inkjet head member. did.

Example B1 Addition amount (% by weight)
Water-soluble pigment 1 (105) 5.0
Compound B1 of formula (I) 8.0
DEGmBE 2.0
Polymer fine particles A 3.0
Diethylene glycol 16.0
2-pyrrolidone 5.0
Triethanolamine 0.8
Remaining amount of ion-exchanged water In the compound B1 of the formula (I), R is a Ra-neopentyl group (Ra- (2,2-dimethyl) propylene group), n + n ′ is 3, and m + m ′ is 1.5. A compound of formula (I).

Example B2
Water-soluble pigment 2 (85) 4.5
Compound B2 of formula (I) 10.0
Polymer fine particles A 3.0
Dipropylene glycol 5.0
Surfinol 465 1.2
Triethanolamine 0.9
Remaining amount of ion-exchanged water In the compound B2 of the formula (I), R is a Ra-t-butyl group (Ra- (1,1-dimethyl) ethylene group), n + n ′ is 3, and m + m ′ is 1. 3 is a compound of formula (I).

Example B3
Water-soluble pigment 3 (90) 5.5
Compound B3 of formula (I) 2.0
Polymer fine particle B 10.0
Diethylene glycol 7.0
Thiodiglycol 3.5
1,6-hexanediol 5.0
Triethanolamine 1.0
Potassium hydroxide 0.1
Residual amount of ion-exchanged water In the compound B3 of the formula (I), R is a Ra-1,3-dimethylbutyl group (Ra- (1,3-dimethyl) butylene group), n + n ′ is 3, m + m ′ Is a compound of formula (I) in which is 1.5.

Example B4
Water-soluble pigment 4 (80) 5.0
Water-soluble dye 1 1.0
Compound B4 of formula (I) 8.0
TEGmBE 3.0
Polymer fine particle C 1.0
Diethylene glycol 3.0
1,5-pentanediol 2.0
Dimethyl-2-imidazolidinone 2.0
Sodium benzoate 0.1
Triethanolamine 0.7
Remaining amount of ion-exchanged water In the compound B4 of the formula (I), R is a Ra-isobutyl group (1-methylpropenyl group), n + n ′ is 3, and m + m ′ is 0.5. A compound.

Example B5
Water-soluble pigment 1 (105) 3.0
Water-soluble dye 1 1.0
Compound B5 of formula (I) 7.0
DEGmBE 2.0
Polymer fine particle D 1.0
Glycerol 14.0
Triethanolamine 0.9
Residual amount of ion-exchanged water In the compound B5 of the formula (I), R is a Ra-n-hexyl group (Ra-n-hexylene group), n + n ′ is 4, and m + m ′ is 2. 50% by weight of the compound of formula (I) wherein R is a Ra-2-ethylhexyl group (Ra-2-ethylhexylene group), n + n ′ is 4, and m + m ′ is 0 It is a mixture of

Example B6
Water-soluble dye 2 5.0
Compound B6 of formula (I) 6.0
TEGmBE 4.0
Glycerin 15.0
Thiodiglycol 2.0
1,5-pentanediol 1.0
Triethanolamine 0.9
Residual amount of ion-exchanged water In the compound B6 of the formula (I), R is a Ra-1,1-dimethylbutyl group (Ra-1,1-dimethylbutylene group), n + n ′ is 4, and m + m ′ is 1. Is a compound of formula (I).

Example B7
Water-soluble dye 3 5.0
Compound B7 of formula (I) 10.0
DEGmBE 3.0
Glycerin 5.0
Trimethylolpropane 1.0
Trimethylolethane 1.0
Surfinol 465 1.0
Triethanolamine 0.5
KOH 0.05
Residual amount of ion-exchanged water In the compound B7 of the formula (I), R is a Ra-1,3-dimethylbutyl group (Ra-1,3-dimethylbutyl group), n + n ′ is 3, and m + m ′ is 1. 50% by weight of the compound of the formula (I), R is a Ra-n-heptyl group (Ra-n-heptylene group), n + n ′ is 3.5, and m + m ′ is 1. ) With 50% by weight of the compound.

Example B8
Water-soluble dye 4 5.5
Compound B8 of formula (I) 6.0
Glycerin 5.0
Diethylene glycol 5.0
Tetrapropylene glycol 5.0
Triethanolamine 0.9
KOH 0.1
Residual amount of ion-exchanged water In the compound B8 of the formula (I), R is a Ra-neopentyl group (Ra- (2,2-dimethyl) propylene group), n + n ′ is 1.0, and m + m ′ is 0.00. 3 and a compound of formula (I) wherein R is a Ra-n-pentyl group (Ra-n-pentylene group), n + n ′ is 2.5, and m + m ′ is 1.0. ), 30% by weight of the compound of formula (I) wherein R is a Ra-isopentyl group (Ra- (1-methyl) butylene group), n + n ′ is 3.0 and m + m ′ is 1.5. A mixture with 20% by weight of the compound.

Print evaluation test The ink compositions of Examples B1 to 8 were subjected to the same print evaluation tests as in Examples A1 to 8 and Comparative Examples B1 to B3, and the bleeding of the obtained printed matter was evaluated. The results were as shown in the table below.

Example C
The pigments 1-4 used in the following examples are as follows.

Pigment 1
Styrene-acrylic acid copolymer (weight average molecular weight 25000, acid value 200) resin 4 parts, 2.7 parts of triethanolamine, 0.4 part of isopropyl alcohol, and 72.9 parts of ion-exchanged water were heated at 70 ° C. It was completely dissolved below. Next, 20 parts of carbon black MA-100 (manufactured by Mitsubishi Kasei Co., Ltd.) is added, premixed, and then dispersed with an Eiger mill (manufactured by Eiger Japan) until the average particle size of the pigment reaches 100 nm (bead filling). The pigment 1 was obtained as a pigment dispersion. The average dispersed particle size of the obtained pigment 1 was 105 nm.

Pigment 2
A dispersion of Pigment 2 was obtained in the same manner as Pigment 1. The average dispersed particle size of Pigment 2 was 85 nm.

Pigments 3 and 4
The surface of carbon black was subjected to oxidation treatment (nitric acid treatment), and a group having a carbonyl group, a carboxyl group, a hydroxyl group, and / or a sulfone group at the terminal was introduced to the surface to obtain pigments 3 and 4. The average dispersed particle size was 90 nm and 80 nm, respectively.

  In the following, dye 1 is direct black 154, dye 2 is direct yellow 132, dye 3 is direct blue 86, and dye 4 is acid red 52.

Example C1 addition amount (% by weight)
Pigment 1 5.0
Compound C1 of the formula (I) 15.0
DEGmBE 2.0
Glycerin 6.0
1,5-pentanediol 5.0
Triethanolamine 0.8
Remaining amount of ion-exchanged water The compound C1 of the formula (I) is a compound in which R is a neopentyl group, n is 1.0, m is 1.5, and T is SO ₃ M (M is sodium). It is a compound of (I).

Example C2
Pigment 2 4.5
Compound C2 of formula (I) 10.0
Dipropylene glycol 5.0
Surfinol 465 1.2
Triethanolamine 0.9
Residual amount of ion-exchanged water In the compound C2 of the formula (I), R is a t-butyl group, n is 1.0, m is 2.0, and T is SO ₃ M (M is triethanolamine). ) Of the formula (I).

Example C3
Pigment 3 5.5
Compound C3 of formula (I) 10.0
Diethylene glycol 7.0
Thiodiglycol 3.5
1,6-hexanediol 5.0
Triethanolamine 1.0
Potassium hydroxide 0.1
Remaining amount of ion-exchanged water In the compound C3 of the formula (I), R is 1,3 dimethylbutyl group, n is 0, m is 4.5, and T is SO ₃ M (M is H). A compound of formula (I).

Example C4
Pigment 4 5.0
Dye 1 1.0
Compound C4 of formula (I) 8.0
TEGmBE 3.0
Diethylene glycol 3.0
1,5-pentanediol 2.0
Dimethyl-2-imidazolidinone 2.0
Sodium benzoate 0.1
Triethanolamine 0.7
Ion-exchanged water balance Compound C4 of formula (I) is a compound in which R is an isobutyl group, n is 3.0, m is 1.0, and T is SO ₃ M (M is ammonia). It is a compound of (I).

Example C5
Pigment 1 3.0
Dye 1 1.0
Compound C5 of formula (I) 7.0
DEGmBE 2.0
Glycerol 14.0
Triethanolamine 0.9
Remaining amount of ion-exchanged water In the compound C5 of the formula (I), R is an n-hexyl group, n is 4.0, m is 1.0, and T is SO ₃ M (M is potassium). A compound of formula (I) 50% by weight, R is a 2-ethylhexyl group, n is 2.0, m is 1.0, and T is SO ₃ M (M is potassium) It is a mixture of 50% by weight of the compound (I).

Example C6
Dye 2 5.0
Compound C6 of formula (I) 6.0
TEGmBE 4.0
Glycerin 15.0
Thiodiglycol 2.0
1,5-pentanediol 1.0
Triethanolamine 0.9
Remaining amount of ion-exchanged water In the compound C4 of the formula (I), R is 1,1-dimethylbutyl group, n is 7.0, m is 1.0, and T is SO ₃ M (M is A compound of formula (I) which is lithium).

Example C7
Dye 3 5.0
Compound C7 of formula (I) 10.0
DEGmBE 3.0
Glycerin 5.0
Trimethylolpropane 1.0
Trimethylolethane 1.0
Surfinol 465 1.0
Triethanolamine 0.5
KOH 0.05
Remaining amount of ion-exchanged water In the compound C4 of the formula (I), R is an n-butyl group, n is 9.0, m is 1.0, and T is SO ₃ M (M is sodium). A compound of formula (I) 50% by weight, R is an n-heptyl group, n is 3.5, m is 2.0, and T is SO ₃ M (M is potassium) It is a mixture of 50% by weight of the compound (I).

Example C8
Dye 4 5.5
Compound C8 of formula (I) 6.0
Glycerin 5.0
Diethylene glycol 5.0
Tetrapropylene glycol 5.0
Triethanolamine 0.9
KOH 0.1
Ion-exchanged water remaining amount Compound C8 of formula (I) has the formula (I) wherein R is a neopentyl group, n is 0, m is 1.0, and T is SO ₃ M (M is potassium). ) Of the formula (I) wherein R is an n-pentyl group, n is 2.5, m is 1.0, and T is SO ₃ M (M is ammonia). 30% by weight of the compound, 20% by weight of the compound of the formula (I) in which R is an isopentyl group, n is 3.0, m is 1.5 and T is SO ₃ M (M is sodium) And a mixture.

Comparative Example C
Comparative Example C1
Pigment 1 5.0
Glycerin 10.0
Dispersant 3.0
Nonionic surfactant 1.0
Remaining amount of ion-exchanged water Nonionic surfactant: Neugen EA160 (Daiichi Kogyo Seiyaku Co., Ltd.)

Comparative Example C2
Dye 2 5.5
DEGmME 7.0
Diethylene glycol 10.0
2-pyrrolidone 5.0
Ion exchange water

Comparative Example C3
Pigment 3 5.5
Dye 1 2.5
Diethylene glycol 10.0
Nonionic surfactant 1.0
Remaining amount of ion-exchanged water Nonionic surfactant: Epan 450 (Daiichi Kogyo Seiyaku Co., Ltd.)

Printing Evaluation Test For the ink compositions of Examples C1 to 8 and Comparative Examples C1 to C3, a printing evaluation test similar to that of Examples A1 to 8 and Comparative Examples B1 to B3 is performed, and bleeding of the obtained printed matter is evaluated. did. The results were as shown in the table below.

Storage Stability Test The inks of Examples C1 to C8 were placed in glass sample bottles and sealed at 60 ° C./one week after sealing. The foreign matter and physical property values (viscosity and surface tension) of the ink before and after being left were examined. As a result, none of the inks had any foreign matter and no change in physical property values.

Example D
Pigment dispersion The pigment dispersion used in Examples D1 to 4 below was prepared as follows. First, 4 parts of a styrene-acrylic acid copolymer (weight average molecular weight 25000, acid value 200) resin, 2.7 parts of triethanolamine, 0.4 part of isopropyl alcohol, and 72.9 parts of ion-exchanged water were added at 70 ° C. It was completely dissolved under heating. Next, 20 parts of carbon black MA-100 (manufactured by Mitsubishi Kasei Co., Ltd.) was added, premixed, and then dispersed with an Eiger mill (manufactured by Eiger Japan) until the average particle size of the pigment reached 100 nm (bead filling The pigment dispersion liquid was obtained. The average dispersed particle size of the obtained pigment was 105 nm.

Water-soluble pigment The water-soluble pigment of Example D5 below is a group in which the surface of carbon black is oxidized (nitric acid treatment), and the terminal has a carbonyl group, a carboxyl group, a hydroxyl group, and / or a sulfone group on the surface. Means a water-soluble pigment into which The average dispersed particle size was 120 nm.

In the compound of formula (I) used in Example D below, EO represents —CH ₂ CH ₂ O—, PO represents —CH (CH ₃ ) —CH ₂ O—, and T represents a hydrogen atom. Is a mixture of compounds of the formula (I) formed by bonding in the order of R- (EO) n- (PO) m-T.

Example D1 Amount (% by weight)
Pigment dispersion 1 5.0
Compound D1 of formula (I) 8.0
DEGmBE 2.0
Glycerin 6.0
1,5-pentanediol 5.0
Triethanolamine 0.8
Residual amount of ion-exchanged water The compound D1 of the formula (I) is a compound of the formula (I) in which R is a neopentyl group, n is 3, and m is 1.5.

Example D2
Pigment dispersion 4.5
Compound D2 of formula (I) 10.0
Dipropylene glycol 5.0
Surfinol 465 1.2
Triethanolamine 0.9
Residual amount of ion-exchanged water The compound D2 of the formula (I) is a compound of the formula (I) in which R is a t-butyl group, n is 3, and m is 1.3.

Example D3
Pigment dispersion 5.5
Compound D3 of formula (I) 10.0
Diethylene glycol 7.0
Thiodiglycol 3.5
1,6-hexanediol 5.0
Triethanolamine 1.0
Potassium hydroxide 0.1
Residual amount of ion-exchanged water The compound D3 of the formula (I) is a compound of the formula (I) in which R is 1,3 dimethylbutyl group, n is 3, and m is 1.5.

Example D4
Pigment dispersion 5.0
Compound D4 of formula (I) 8.0
TEGmBE 3.0
Diethylene glycol 3.0
1,5-pentanediol 2.0
Dimethyl-2-imidazolidinone 2.0
Sodium benzoate 0.1
Triethanolamine 0.7
Residual amount of ion-exchanged water The compound D4 of the formula (I) is a compound of the formula (I) in which R is an isobutyl group, n is 3, and m is 0.5.

Example D5
Water-soluble pigment 3.0
Compound D5 of formula (I) 7.0
DEGmBE 2.0
Glycerol 14.0
Triethanolamine 0.9
Remaining amount of ion-exchanged water In the compound D5 of the formula (I), R is an n-hexyl group, n is 4, and m is 2, 50% by weight of the compound of the formula (I), and R is 2-ethylhexyl A mixture with 50% by weight of a compound of the formula (I) in which n is 4 and m is 0.

Evaluation Test Using the above Examples D1 to D5, Conqueror paper, Favorit paper, Modo Copy paper, Rapid Copy paper, EPSON EPP paper, Xerox 4024 paper, Xerox 10 paper, Nenha Bond paper, Ricopy 6200 paper, Yamari paper, Printing was performed on Xerox R paper, and the sharpness and quick drying property of the printed image were evaluated according to the following criteria. In addition, the evaluation result was made into the average value with respect to said various paper.

Evaluation item 1: Edge sharpness Evaluation A: There is no blur in most printing patterns, the edge is sharp, and there is no difference depending on the paper type.
Evaluation B: Edges are slightly disturbed depending on the printing pattern, but there is no practical problem and the difference depending on the paper type is small.
Evaluation C: Edges are disturbed by the printing pattern on all paper types or some of the paper types, and the image is blurred, which is not practical.

Evaluation item 2: Quick-drying evaluation A: The printed material does not soil even when touched with a finger after 30 seconds.
Evaluation B: The printed matter becomes soiled when touched with a finger after 30 seconds.
The results were as shown in the table below.

Example D1 D2 D3 D4 D5
Evaluation 1 B A B A B
Evaluation 2 A A A A A

Example E
The water-soluble pigments 1 to 4 in the following examples are water-soluble pigments having a group having a carbonyl group, a carboxyl group, a hydroxyl group, or a sulfone group at the terminal by oxidation treatment on the surface of carbon black having a particle size of 10 to 300 nm. Means. Further, the average particle diameter of the water-soluble pigment was as indicated by the unit of nm in parentheses.

  In addition, the compound of the formula (I) used in Example E below has the formula (I) in which T represents a hydrogen atom and is bonded in the order of R- (EO) n1- (PO) m1-T. It is a mixture of a compound and a compound of formula (I) in which T represents a hydrogen atom and is bonded in the order of R- (PO) m2- (EO) n2-T. Hereinafter, the former is referred to as the compound of formula (I-1), and the latter is referred to as the compound of formula (I-2).

  In the following, the water-soluble dye 1 is direct black 154, the water-soluble dye 2 is direct yellow 132, the water-soluble dye 3 is direct blue 86, and the water-soluble dye 4 is acid red 52.

  In addition, 0.1 to 1% of Proxel XL-2 is added to all of the ink compositions below, and 0.001 to 0.05% of benzotriazole is added to prevent corrosion of the inkjet head member. did.

Example E1 Amount of addition (% by weight)
Water-soluble pigment 1 (105) 5.0
Compound E1 of formula (I-1) 1.0
Compound E1 of formula (I-2) 1.0
DEGmBE 3.0
Polymer fine particles A 3.0
Diethylene glycol 16.0
2-pyrrolidone 5.0
Residual amount of ion-exchanged water The compound E1 of the formula (I-1) is a compound of the formula (I) in which R1 is a neopentyl group, n1 is 3, and m1 is 1.5. In addition, the compound E1 of the formula (I-2) is a compound of the formula (I) in which R is a hexyl group, n2 is 5, and m2 is 2.

Example E2
Water-soluble pigment 2 (85) 4.5
Compound E2 of formula (I-1) 2.0
Compound E2 of formula (I-2) 1.0
Polymer fine particles A 3.0
Dipropylene glycol 5.0
Surfinol 465 1.2
Residual amount of ion-exchanged water The compound E2 of the formula (I-1) is a compound of the formula (I) in which R1 is a t-butyl group, n1 is 3, and m1 is 1.3. In addition, the compound E2 of the formula (I-2) is a compound of the formula (I) in which R is an iso-butyl group, n2 is 3, and m2 is 1.

Example E3
Water-soluble pigment 3 (90) 5.5
Compound E3 of formula (I-1) 1.0
Compound E3 of formula (I-2) 2.0
Polymer fine particle B 10.0
Diethylene glycol 7.0
Thiodiglycol 3.5
1,6-hexanediol 5.0
Potassium hydroxide 0.1
Remaining amount of ion-exchanged water In the compound E3 of the formula (I-1) and the compound E3 of the formula (I-2), R is 1,3-dimethylbutyl group, n1 + n2 is 3, m1 + m2 is 1.5 A compound of formula (I).

Example E4
Water-soluble pigment 4 (80) 5.0
Water-soluble dye 1 1.0
Compound E4 of formula (I-1) 4.0
Compound E4 of formula (I-2) 4.0
TEGmBE 3.0
Polymer fine particle C 1.0
Diethylene glycol 3.0
1,5-pentanediol 2.0
Dimethyl-2-imidazolidinone 2.0
Sodium benzoate 0.1
Triethanolamine 0.7
Remaining amount of ion-exchanged water Compound E4 of formula (I-1) and compound E4 of formula (I-2) are compounds of formula (I) wherein R is an isobutyl group, n1 + n2 is 3, and m1 + m2 is 0.5 It is.

Example E5
Water-soluble pigment 1 (105) 3.0
Water-soluble dye 1 1.0
Compound E5 of formula (I-1) 4.0
Compound E5 of formula (I-2) 3.0
DEGmBE 2.0
Polymer fine particle D 1.0
Glycerin 10.0
Diethylene glycol 4.0
Remaining amount of ion-exchanged water In the compound E5 of the formula (I-1) and the compound E5 of the formula (I-2), R is an n-hexyl group, n1 + n2 is 4, and m1 + m2 is 2. A mixture of 50% by weight of the compound of I) with 50% by weight of the compound of formula (I) in which R is a 2-ethylhexyl group, n1 + n2 is 4, and m1 + m2 is 0.

Example E6
Water-soluble dye 2 5.0
Compound E6 of formula (I-1) 5.0
Compound E6 of formula (I-2) 1.0
TEGmBE 4.0
Glycerin 10.0
Thiodiglycol 2.0
1,5-pentanediol 1.0
Remaining amount of ion-exchanged water In the compound E6 of the formula (I-1) and the compound E6 of the formula (I-2), R is a 1,1-dimethylbutyl group, n1 + n2 is 4, and m1 + m2 is 1. It is a compound of (I).

Example E7
Water-soluble dye 3 5.0
Compound E7 of formula (I-1) 8.0
Compound E7 of formula (I-2) 2.0
DEGmBE 3.0
Glycerin 5.0
Trimethylolpropane 1.0
Trimethylolethane 1.0
Surfinol 465 1.0
KOH 0.05
Remaining amount of ion-exchanged water In compound E7 of formula (I-1) and compound E7 of formula (I-2), R is a 1,3-dimethylbutyl group, n1 + n2 is 3, m1 + m2 is 1, A mixture of 50% by weight of a compound of the formula (I) with a compound of the formula (I) in which R is an n-heptyl group, n1 + n2 is 3.5 and m1 + m2 is 1.

Example E8
Water-soluble dye 4 5.5
Compound E8 of formula (I-1) 3.0
Compound E8 of formula (I-2) 3.0
Glycerin 5.0
Diethylene glycol 5.0
Tetrapropylene glycol 5.0
Remaining amount of ion-exchanged water In compound E8 of formula (I-1) and compound E8 of formula (I-2), R is a neopentyl group, n1 + n2 is 1.0, and m1 + m2 is 0.3. 50% by weight of the compound of the formula (I), 30% by weight of the compound of the formula (I) in which R is an n-pentyl group, n1 + n2 is 2.5, and m1 + m2 is 1.0, and R is an isopentyl group Wherein n1 + n2 is 3.0 and m1 + m2 is 1.5.

Print evaluation test About the ink composition of said Example E1-8, the print evaluation test similar to Example A1-8 and Comparative Example B1-3 was done, and the bleeding of the obtained printed matter was evaluated. The results were as shown in the table below.

Claims (13)

A coloring material, a water-soluble organic solvent, one or more selected from the group consisting of propylene glycol monobutyl ether, dipropylene glycol monobutyl ether, diethylene glycol monobutyl ether, and triethylene glycol monobutyl ether, water, and the following formula ( Ink for ink jet recording, comprising at least a mixture of two or more compounds represented by I):

[In the above formula,
EO represents an ethyleneoxy group,
PO represents a propyleneoxy group,
T represents SO ₃ M (where M represents a hydrogen atom, an alkali metal, an inorganic base, or an organic amine);
m and n represent integers;
k represents a natural number of 1 to 4 or more,
R represents C _a H _{2a + 2-k} (where a represents a natural number of 4 to 10),
The order of EO and PO is not limited in [], and may be random or block.
When n and m are each expressed as an average value of the mixture of the compounds of formula (I) contained in the ink composition, n is in the range of 1 to 10, and m is in the range of 0 to 5.]   The ink according to claim 1, wherein n and m in the mixture of compounds of formula (I) satisfy n / m ≧ 0.5.   The ink according to claim 1 or 2, wherein the compound of formula (I) has an average molecular weight of 2000 or less.   A mixture of compounds of formula (I) wherein R is a butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, or decyl group; and R is a butyl group, The ink according to any one of claims 1 to 3, which is a mixture with a compound of formula (I) which is a pentyl group, hexyl group, heptyl group, octyl group, nonyl group or decyl group. The ink according to any one of claims 1 to 4, wherein R represents linear or branched C _a H _{2a + 2-k} .   The ink according to any one of claims 1 to 5, comprising (di) propylene glycol monobutyl ether in an amount of 0 to 10% by weight.   The ink according to claim 6, wherein a weight ratio of the compound of the formula (I) to (di) propylene glycol monobutyl ether is 1: 0 to 1:10.   The ink according to any one of claims 1 to 7, comprising 0 to 5% by weight of an acetylene glycol surfactant.   The ink according to claim 8, wherein the weight ratio of the compound of the formula (I) to the acetylene glycol surfactant is 1: 0 to 1: 3.   The ink according to any one of claims 1 to 9, comprising 0 to 20% by weight of di (tri) ethylene glycol monobutyl ether.   The ink according to claim 10, wherein the weight ratio of the compound of the formula (I) to di (tri) ethylene glycol monobutyl ether is 1: 0 to 1:10.   The ink according to any one of claims 1 to 11, wherein the water-soluble colorant is a water-soluble dye and / or a water-soluble pigment dispersible in water.   An ink-jet recording method for performing printing by discharging droplets of an ink composition and attaching the droplets to a recording medium, wherein the ink composition according to any one of claims 1 to 12 is used. An ink jet recording method using