KR102140258B1 - Photocurable pigment dispersion liquid and photocurable ink composition using the same - Google Patents

Abstract

The present invention is a vinyl-based copolymer comprising 46% to 73% by weight of a vinyl acetal repeating unit, 0.1% to 5% by weight of a vinyl ester repeating unit, and 26% to 52% by weight of a vinyl alcohol repeating unit; Pigment; Photo-curable resins; And an organic solvent; and a photocurable ink composition using the same.

Description

Photocurable pigment dispersion and photocurable ink composition using the same{PHOTOCURABLE PIGMENT DISPERSION LIQUID AND PHOTOCURABLE INK COMPOSITION USING THE SAME}

The present invention relates to a photocurable pigment dispersion and a photocurable ink composition using the same. More specifically, the present invention relates to a photocurable pigment dispersion and a photocurable ink composition using the same, which can exhibit high mechanical properties, low viscosity, and excellent stability even when stored for a long time.

Inkjet printing has increased in popularity in recent years due to its relatively high speed and excellent image resolution. In addition, inkjet printing devices associated with computers can provide versatility in design and final images. Due to the increasing popularity and efficiency of use for inkjet printing, inkjet printing has become a suitable alternative to previously known printing methods.

Inks commonly used in inkjet printers include water-based inks, solvent-based inks, and photo-curable inks. Among them, photo-curable ink is widely considered as an alternative ink for printing on various types of uncoated and non-porous substrates. By using photocuring, the ink can be dried quickly without the need for volatilization of large amounts of water or solvent, minimizing the use of volatile solvents, curing time is short, and curing is possible even at low temperatures. It can be applied to various fields through the formation of coloring patterns.

In general, the photo-curable ink composition is composed of a photopolymerizable resin and an initiator, a pigment, a diluent, and other additives. The photo-curable ink composition that can be applied to an inkjet printer is low viscosity, low volatility, long-term stability, spraying from the nozzle of the print head Rapid drying of ink dots derived from the droplets to be obtained, resistance to scratching and adhesion to a substrate are essential.

Particularly, in the case of a pigment, it must be properly dispersed in a photocurable ink composition to maintain stability, but uniformity of a film thickness of a coating film may be reduced in a coating process of a photocurable ink, or sensitivity may be prevented in an exposure process. In addition, stability caused by long-term storage is rapidly reduced, thereby preventing problems such as clogging of the head.

To this end, studies are being conducted to disperse the pigment in a more stable state in the photocurable ink composition. In particular, in US Patent Publication 2010-0215921 (Photocurable ink composition, ink jet recording method, recorded matter, ink set, ink cartridge, and recording apparatus), a method of improving dispersibility of a pigment by adding a dispersing agent to a photocurable ink, etc. Although this has been proposed, there is a limitation in that the dispersant acts as an impurity in the photocurable ink to increase the viscosity of the photocurable ink, and decrease the curing sensitivity and the properties of the formed film.

Accordingly, there is a need to develop a photocurable ink capable of exhibiting low viscosity, high mechanical properties, and excellent stability while improving the dispersibility of the pigment.

The present invention is to provide a photocurable pigment dispersion having low viscosity, high mechanical properties, and excellent stability even when stored for a long time.

In addition, the present invention is to provide a photocurable ink composition using the photocurable pigment dispersion.

In the present specification, a vinyl-based copolymer comprising 46% to 73% by weight of a vinyl acetal repeat unit, 0.1% to 5% by weight of a vinyl ester repeat unit, and 26% to 52% by weight of a vinyl alcohol repeat unit; Pigment; Photo-curable resins; And an organic solvent; a photocurable pigment dispersion is provided.

In addition, in the present specification, a vinyl-based copolymer including 46 to 73 wt% of a vinyl acetal repeating unit, 1 to 5 wt% of a vinyl ester repeating unit, and 25 to 50 wt% of a vinyl alcohol repeating unit; Pigment; Photo-curable resins; Provided is a photocurable ink composition comprising an organic solvent and a photoinitiator.

Hereinafter, a photocurable pigment dispersion according to a specific embodiment of the present invention and a photocurable ink composition using the same will be described in more detail.

In the present specification, (meth)acrylate is meant to include both acrylate (acrylate) and (meth)acrylate [(meth)acrylate].

According to an embodiment of the present invention, a vinyl copolymer comprising 46% to 73% by weight of a vinyl acetal repeating unit, 0.1% to 5% by weight of a vinyl ester repeating unit, and 26% to 52% by weight of a vinyl alcohol repeating unit; Pigment; Photo-curable resins; And an organic solvent; a photocurable pigment dispersion may be provided.

The present inventors use the vinyl-based copolymer as a dispersant, including 46% to 73% by weight of the aforementioned vinyl acetal repeating unit, 0.1% to 5% by weight of the vinyl ester repeating unit, and 26% to 52% by weight of the vinyl alcohol repeating unit. Then, while improving the dispersibility of the pigment in the photocurable pigment dispersion, it was confirmed through experiments that the viscosity of the dispersion can be kept low and the invention was completed.

In particular, the photocurable ink composition prepared using the photocurable pigment dispersion can exhibit a low level of viscosity and high adhesion strength to be used as a photocurable ink, and has excellent stability due to little change in viscosity even when stored for a long time. It was confirmed that it can be implemented.

In addition, the photocurable pigment dispersion may contain a photocurable resin, improve miscibility within the photocurable ink composition, and minimize the content of volatile components such as organic solvents. When the photocurable pigment dispersion does not contain a photocurable resin or is excessively reduced, as the content of a solvent that is a volatile component in the photocurable ink composition prepared from the photocurable pigment dispersion increases, the surface quality of the coating finally formed This may decrease or the physical properties may decrease.

Specifically, the content of the photocurable resin with respect to the photocurable pigment dispersion may be 10 wt% to 40 wt%, or 20 wt% to 35 wt%, or 30 wt% to 35 wt%.

The photocurable resin may include monomers and oligomers curable by energy ray irradiation. Examples of the photo-curable resin are not particularly limited. For example, epoxy-based resin, oxetane-based resin, vinyl ether-based resin, (meth)acrylate-based resin, unsaturated polyester-based resin, or a mixture of two or more thereof Can be used.

The epoxy-based resin may include an epoxy monomer and an epoxy oligomer in any organic or inorganic system having an epoxy functional group. Examples of the epoxy-based resin are not particularly limited, for example, bisphenol A-type epoxy resin, bisphenol F-type epoxy resin, biphenyl-type epoxy resin, tetramethylbiphenyl-type epoxy resin, phenol novolac-type epoxy resin, cresol Novolak type epoxy resin, triphenyl methane type epoxy resin, tetraphenyl ethane type epoxy resin, dicyclopentadiene-phenol addition reaction type epoxy resin, phenol aralkyl type epoxy resin, naphthol novolak type epoxy resin, naphthol aralkyl type Epoxy resins Naphthol-phenol coaxial novolac type epoxy resin, naphthol-cresol coaxial novolac type epoxy resin, aromatic hydrocarbon formaldehyde resin modified phenol resin type epoxy resin, biphenyl modified novolac type epoxy resin, tetrabromo bisphenol A type epoxy Resins, brominated phenol novolac-type epoxy resins, or mixtures of two or more thereof.

The oxetane-based resin may include oxetane monomers and oxetane oligomers in any organic or inorganic system having oxetane functional groups. Examples of the oxetane-based resin are not particularly limited, for example, 3-ethyl-3-hydroxymethyloxetane, 1,4-bis[(3-ethyl-3-oxetanyl)methoxy]methyl] Benzene, 3-ethyl-3-(phenoxy methyl) oxetane, 3-ethyl-3-(2-ethylhexyloxymethyl) oxetane, 4,4´-bis[3-ethyl-(3-oxeta) Neil) methoxymethyl] biphenyl, silsesquioxane-modified oxetane, oxetane (meth) acrylate, and the like can be used.

The vinyl ether-based resin may include a vinyl ether monomer and a vinyl ether oligomer. Examples of the vinyl ether monomer are not particularly limited, but for example, an aliphatic divinyl ether compound, an alicyclic divinyl ether compound, an aromatic divinyl ether compound, or the like can be used.

The (meth)acrylate-based resin may include a (meth)acrylate monomer and a (meth)acrylate oligomer. The example of the (meth)acrylate monomer is not particularly limited, but, for example, a substituted or unsubstituted (meth)acrylate, (meth)diacrylate, or the like can be used.

Specifically, for example, acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, butyl acrylate, butyl methacrylate, polyethylene glycol Monoacrylate, polyethylene glycol monomethacrylate, glycerin diacrylate, glycerin dimethacrylate, trimethylol propane diacrylate, trimethylol propane dimethacrylate, trimethylol propane triacrylate, trimethylol propane trimethacryl Rate, pentaerythritol triacrylate, pentaerythritol trimethacrylate, dipentaerythritol pentaacrylate, dipentaerythritol pentamethacrylate, glycyridyl isocyanurate diacrylate, glyceride Cyridyl isocyanurate dimethacrylate, propoxylate diglycidyl triacrylate, tris(2-hydroxyethyl)isocyanurate diacrylate, tris(2-hydroxyethyl)isocyanurate Dimethacrylate, tris(2-hydroxyethyl)isocyanurate triacrylate, tris(2-hydroxyethyl)isocyanurate trimethacrylate, hydroxyethyl methacrylate, hydroxyethyl acrylate , Hydroxy propyl methacrylate, hydroxy propyl acrylate, hydroxy butyl methacrylate, hydroxy butyl acrylate, and the like.

The unsaturated polyester resin may include a diacid or diacid anhydride monomer containing an unsaturated functional group, a polyol monomer, and an oligomer reacting the monomers. Examples of the divalent acid or diacid anhydride monomer including the unsaturated group are not particularly limited. For example, phthalic acid, isophthalic acid, maleic acid, phthalic anhydride, maleic anhydride, or a mixture of two or more thereof may be used. In addition, the examples of the polyol monomer are not particularly limited, for example, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, neopentyl glycol, or mixtures of two or more thereof can be used.

Examples of the organic solvent are not particularly limited, for example, ketone types such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene, and tetramethyl benzene; cellosolve, methyl cellosolve, and propylene glycol mono Glycol ethers such as methyl ether and propylene glycol monoethyl ether; acetic acid esters such as ethyl acetate, butyl acetate and cellosolve acetate; alcohols such as ethanol and propano; aliphatic hydrocarbons such as pentane, octane and decane; Petroleum-based solvents such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, and absorbent naphtha Etc. are mentioned, Preferably butyl cellosolve can be used.

According to the use of the butyl cellosolve, the polyvinyl acetal repeating unit 46 wt% to 73 wt%, the polyvinyl ester repeating unit 1 wt% to 5 wt% and the polyvinyl alcohol repeating unit 25 wt% in the photocurable pigment dispersion The solubility in the copolymer containing 50% by weight may be improved, and an appropriate level of boiling point may be formed in the inkjet process.

The photo-curable resin and the organic solvent may be included in a weight ratio of 1:1.2 to 1:3. Accordingly, it is possible to improve the coating property through inkjet printing by maintaining the viscosity of the ink finally produced.

On the other hand, the photocurable pigment dispersion is a vinyl-based copolymer containing 46% to 73% by weight of a vinyl acetal repeating unit, 0.1% to 5% by weight of a vinyl ester repeating unit, and 26% to 52% by weight of a vinyl alcohol repeating unit. It can contain. The vinyl-based copolymer may be used as a dispersant for dispersing the pigment in the photocurable pigment dispersion.

The vinyl acetal repeating unit means a repeating unit included in a polymer obtained by homopolymerizing a vinyl acetal monomer, and the vinyl ester repeating unit means a repeating unit included in a polymer obtained by homopolymerizing a vinyl ester monomer, and the vinyl The alcohol repeating unit means a repeating unit included in a polymer obtained by homopolymerizing a vinyl alcohol monomer.

Examples of the vinyl acetal repeating unit are not particularly limited, for example, a vinyl butyral repeating unit, a vinyl isobutyral repeating unit, and a vinyl propyral repeating unit. It may include a unit, a vinyl acetacetal repeating unit, a vinyl formal repeating unit, or a mixture of two or more of these, preferably repeating a polyvinyl butyral represented by the following formula (1) Units can be used.

[Formula 1]

The content of the polyvinyl acetal repeating unit may be 46% to 73% by weight, or 50% to 70% by weight based on the weight of the vinyl-based copolymer. When the content of the vinyl acetal repeating unit is less than 46% by weight based on the weight of the vinyl-based copolymer, the solubility of the vinyl-based copolymer in an organic solvent and a photo-curable resin decreases, and thus it may be difficult to implement sufficient dispersibility. have. In addition, when the content of the vinyl acetal repeating unit is more than 73% by weight based on the weight of the vinyl copolymer, stability of the ink composition and physical properties of the coating prepared from the ink composition may be reduced.

The vinyl ester repeating unit may include a repeating unit represented by Formula 2 below.

[Formula 2]

In Chemical Formula 2, R may be hydrogen or a straight or branched alkyl group having 1 to 20 carbon atoms.

Specifically, the vinyl ester repeating unit is a vinyl acetate repeating unit, a vinyl formate repeating unit, a vinyl propionate repeating unit, and a vinyl butyrate repeating unit. It may include a unit, a vinyl caprate repeating unit, or a mixture of two or more thereof, and preferably, a vinyl acetate repeating unit represented by the following Chemical Formula 3 may be used.

[Formula 3]

The content of the vinyl ester repeating unit may be 0.1 wt% to 5 wt%, or 1 wt% to 4 wt% based on the weight of the vinyl copolymer. When the content of the vinyl ester repeating unit is more than 5% by weight based on the weight of the vinyl-based copolymer, stability of the ink composition may be reduced.

The vinyl alcohol repeating unit may include a repeating unit represented by Formula 4 below.

[Formula 4]

The content of the vinyl alcohol repeating unit may be 26% to 52% by weight, or 30% to 40% by weight based on the weight of the vinyl-based copolymer. When the content of the repeating unit of vinyl alcohol is less than 26% by weight based on the weight of the vinyl-based copolymer, adhesive strength may decrease when manufacturing the film. In addition, when the content of the repeating unit of vinyl alcohol is greater than 52% by weight based on the weight of the vinyl-based copolymer, the storage stability may decrease due to an increase in viscosity during long-term storage of the ink.

The weight average molecular weight of the vinyl-based copolymer may be 1,000 g/mol to 80,000 g/mol, or 10,000 g/mol to 60,000 g/mol, or 30,000 g/mol to 50,000 g/mol. If the weight-average molecular weight of the vinyl-based copolymer is less than 1,000 g/mol, dispersion stability may decrease, and if the weight-average molecular weight of the vinyl-based copolymer exceeds 80,000 g/mol, the viscosity increases during ink preparation and the ink May degrade the performance.

Meanwhile, the photocurable pigment dispersion may include a pigment.

Examples of the pigment are not particularly limited, for example, CI pigment yellow 1, 3, 12, 13, 14, 15, 16, 17, 20, 24, 31, 53, 83, 86, 93, 94, Yellow pigments such as 109, 110, 117, 125, 128, 137, 138, 139, 147, 148, 150, 153, 154, 166, 173, 194, 214; Brown pigments such as C.I. pigment orange 13, 31, 36, 38, 40, 42,43, 51, 55, 59, 61, 64, 65, 71, 73; CI Pigment Red 9, 97, 105, 122, 123, 144, 149, 166, 168, 176, 177, 180, 192, 209, 215, 216, 224, 242, 254, 255, 264, 265 Pigment; Blue pigments such as C.I. pigment blue 15, 15:3, 15:4, 15:6, 60; Violet pigments such as C.I. pigment violet 1, 19, 23, 29, 32, 36, 38; Green pigments such as C.I. pigment green 7, 36, and 58; Color pigments such as C.I. pigment brown 23 and 25; Black pigments such as C.I. pigment black 1, 7, carbon black, titanium black, iron oxide, etc. can be used, preferably carbon black.

The carbon black may have an oil absorption of 10 ml/100 g to 200 ml/100 g, or 30 ml/100 g to 150 ml/100 g, or 40 ml/100 g to 100 ml/100 g. The oil absorption is an index indicating the performance of the pigment, and means the amount of oil required to knead the pigment with oil to make a hard dough.

When the oil absorption amount of the carbon black is less than 10 ml/100 g, it may be difficult to implement blackness, and when the oil absorption amount of the carbon black is more than 200 ml/100 g, workability of the inkjet process may decrease due to an increase in viscosity. .

The pigment may be included in 10% by weight to 40% by weight, or 15% by weight to 30% by weight based on the weight of the photocurable pigment dispersion, and if the content of the pigment is less than 10% by weight, the photocurable pigment dispersion Pigment content in the ink composition using may be excessively reduced. In addition, when the content of the pigment is more than 40% by weight, the viscosity of the photocurable pigment dispersion may be excessively increased, making it difficult to perform the dispersion process.

5 parts by weight to 40 parts by weight of the vinyl-based copolymer, or 7 parts by weight to 30 parts by weight based on 100 parts by weight of the pigment. When the content of the vinyl-based copolymer is less than 5 parts by weight based on 100 parts by weight of the pigment, it may be difficult to secure dispersion stability of the photocurable pigment dispersion, and the content of the vinyl-based copolymer based on 100 parts by weight of the pigment When it exceeds 40 parts by weight, the viscosity of the ink may increase.

에서 측정한 점도가 1,500 mPa·s 이하, 또는 5 mPa·s 내지 1,500 mPa·s, 또는 10 mPa·s 내지 1,000 mPa·s일 수 있다. 상기 광경화성 안료 분산액의 점도가 1,500 mPa·s 초과로 지나치게 증가하면, 비드밀을 이용한 분산이 효과적으로 이루어지기 어려울 수 있고, 상기 광경화성 안료 분산액을 이용한 잉크 조성물에서도 점도 상승이 발생할 수 있다.The photocurable pigment dispersion is 25

The viscosity measured at may be 1,500 mPa · s or less, or 5 mPa · s to 1,500 mPa · s, or 10 mPa · s to 1,000 mPa · s. When the viscosity of the photocurable pigment dispersion is excessively increased to more than 1,500 mPa·s, dispersion using a bead mill may be difficult to be effectively achieved, and viscosity increase may occur in an ink composition using the photocurable pigment dispersion.

Examples of a method for preparing the photocurable pigment dispersion are not particularly limited, for example, 46 to 73 wt% of the vinyl acetal repeating unit, 0.1 to 5 wt% of the vinyl ester repeating unit, and a repeating unit of vinyl alcohol A method of mixing a vinyl-based copolymer containing 26% by weight to 52% by weight, a photocurable resin, and an organic solvent, followed by linear dispersion by adding a pigment to the mixture, and dispersion using a bead mill after linear dispersion may be used. have.

More specifically, the linear dispersion may be performed at a rate of 300 to 20,000 rpm for 15 minutes to 1 hour, and dispersion using the bead mill may be performed for 1 to 50 passes.

On the other hand, according to another embodiment of the invention, vinyl acetal repeat unit 46 wt% to 73 wt%, vinyl ester repeat unit 1 wt% to 5 wt% and vinyl alcohol repeat unit 25 wt% to 50 wt% vinyl-based air containing coalescence; Pigment; Photo-curable resins; A photocurable ink composition comprising an organic solvent and a photoinitiator may be provided.

Since the photo-curable ink composition is used as a photo-curable ink, it can exhibit an appropriate level of low viscosity and high adhesive strength, and even when stored for a long time, little change in viscosity can realize excellent stability.

The content of the pigment component includes the content described above with respect to the one embodiment. The content of the pigment with respect to the photocurable ink composition may be 0.1 wt% to 10 wt%, or 1 wt% to 8 wt%, or 3 wt% to 6 wt%. If the content of the pigment for the photo-curable ink composition is less than 0.1% by weight, the pigment content is excessively reduced, thereby reducing the color development effect. In addition, when the content of the pigment for the photocurable ink composition is more than 10% by weight, the physical properties of the film formed from the photocurable ink composition may decrease while the pigment acts as an impurity, and in the case of a pigment, especially carbon black Due to light absorption in the region, as the transmittance of ultraviolet light decreases, curing of the photocurable ink composition may become difficult.

The photo-curable resin may be an epoxy-based resin, an oxetane-based resin, a vinyl ether-based resin, an acrylate-based resin, an unsaturated polyester-based resin, or a mixture of two or more thereof. The epoxy-based resin, oxetane-based resin, vinyl ether-based resin, acrylate-based resin, and unsaturated polyester-based resin include the contents described above with respect to the one embodiment.

The content of the photo-curable resin with respect to the photo-curable ink composition may be 50% to 80% by weight, or 55% to 75% by weight, or 60% to 70% by weight. Accordingly, the viscosity of the photocurable ink composition may be kept low to improve coating properties through inkjet printing, and physical properties of the formed film may also be improved.

The vinyl acetal repeating unit 46 wt% to 73 wt%, vinyl ester repeating unit 1 wt% to 5 wt% and vinyl alcohol repeating unit 25 wt% to 50 wt% for the content of the vinyl-based copolymer in the above implementation The above-mentioned contents are included.

The photoinitiator may serve to generate radicals by energy ray irradiation for curing of the photocurable ink composition. The photoinitiator may be included in an amount of 0.1% to 10% by weight, or 4% to 9% by weight based on the weight of the photocurable ink composition.

Examples of the photoinitiator are not particularly limited, and examples thereof include alpha hydroxy ketone compounds, alpha amino ketone compounds, phenylglyoxylate compounds, acrylphosphine oxide compounds, and benzophenone compounds. .

More specifically, the photoinitiators include non-acetyl, benzoin, benzyl, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2, 2-diethoxy-2-phenyl acetophenone, 1,1-dichloroacetophenone, 1-hydroxycyclohexylphenylketone, 1-hydroxy-1-methylethyl-phenol ketone, p-isopropyl-α-hydroxy Isobutylphenone, N,N-dimethylaminoacetophenone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, ethyl-p-dimethylaminobenzoate, 2- Methylanthraquinone, 2-ethylanthraquinone, 2-t-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone, 2-aminoanthraquinone, 2,4-dimethylthioxanthone, 2-chlorothiokine Xanthone, 2,4-diisopropylthioxanthone, acetophenone dimethyl ketal, benzyl dimethyl ketal, benzophenone, methyl benzophenone, trimethyl benzophenone (TZT), 4-benzoyl 4'-methyldiphenyl sulfide, 4, 4'-dichlorobenzophenone, diethylthioxanthone (DETX), 2-isopropylthioxanthone (ITX), 4,4'-bisdiethylaminobenzophenone, 2-methyl-1-[4-(methylthio) Phenyl]-2-morpholinopropanone-1 (IRGACURE 907), 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1 (IRGACURE 369), 2-dimethylamino-2 -(4-methylbenzyl)-1-(4-morpholinylphenyl)-butanone-1 (IRGACURE 379), bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (IRGACURE 819), 2 ,4,6-trimethylbenzoyldiphenylphosphine oxide (TPO), bis(eta 5-2,4-cyclopentadien-1-yl)bis[2,6-difluoro-3-(1H-pyrrole- 1-yl)phenyl]titanium, 2-hydroxy-1-{1-[4-(2-hydroxy-2-methyl-propionyl)-phenyl]-1,3,3-trimethyl-indan-5-yl}- 2-methyl-propan-1-one (ESACURE ONE), 1-propanone, 1-[4-[(4-benzoylphenyl)thio] phenyl]-2-methyl-2-[(4-methylphe nyl)sulphonyl] (ESACURE 1001M), bis-N,N-[4-dimethyiaminobenzoyl) oxyethylen-l-yl]-methylamine (ESACURE A198), or mixtures of two or more thereof.

The viscosity of the photocurable ink composition may be 30 mpa·s or less at 25° C., or 5 mPa·s to 30 mPa·s, or 10 mPa·s to 22 mPa·s. Inkjet printing performance may be improved as the viscosity of the photocurable ink composition is lowered to a certain level or less. When the viscosity of the photo-curable ink composition is more than 30 mPa·s at 25° C., the coatability by inkjet printing decreases and film properties may deteriorate.

The photo-curable ink composition may have an adhesion strength of 4B or more, or 4B to 5B, to glass measured by ASTM D3359. When the adhesive strength of the photo-curable ink composition is 4B or less, or 1B to 3B, adhesion of the coating prepared by curing the photo-curable ink composition to the substrate decreases, and surface quality may be deteriorated.

The photocurable ink composition may further include an additive including a surfactant, an antioxidant, a photopolymerization accelerator, a surface control agent, or a mixture of two or more thereof. Examples of specific surfactants, antioxidants, photopolymerization accelerators, and surface control agents are not particularly limited, and various additives widely used in the field of photocurable ink technology can be used without limitation.

Examples of the method of manufacturing the photo-curable ink composition is not particularly limited, and for example, a base material including a photo-curable resin, an organic solvent, a photoinitiator, and other additives, and a vinyl acetal repeating unit of 46% to 73% by weight of the embodiment. , Vinyl-based copolymer containing 0.1% to 5% by weight of a vinyl ester repeating unit and 26% to 52% by weight of a vinyl alcohol repeating unit; Pigment; Photo-curable resins; And an organic solvent; a method of mixing and dispersing a photocurable pigment dispersion containing a stirrer or a homogenizer until it becomes uniform using a disperser such as a roll mill, a sand mill, a ball mill, a bead mill or an attritor can be used. have.

Specifically, the photo-curable resin and the organic solvent included in the parent agent may include content for the photo-curable resin and the organic solvent contained in the photo-curable pigment dispersion of the embodiment.

The photo-curable ink composition may be applied to an inkjet printer, for example, and applied to various substrates to form a film on the substrate through curing using ultraviolet (UV) light. The example of the inkjet printer is not particularly limited, and for example, an on-demand or piezo-type inkjet printer may be used. In addition, although the example of the said base material is also not specifically limited, For example, a printed wiring board formed with circuits etc. can be used.

According to the present invention, a photocurable pigment dispersion and a photocurable ink composition using the same can be provided with a low viscosity, high mechanical properties, and excellent stability even when stored for a long time.

The invention is described in more detail in the following examples. However, the following examples are only illustrative of the present invention, and the contents of the present invention are not limited by the following examples.

<Examples 1 to 2: Preparation of carbon black dispersion and ink composition>

Example 1

(1) Preparation of carbon black dispersion

14 g of the dispersant described in Table 1 was dissolved in 546 g of a 4:6 mixture of an epoxy resin and butyl cellosolve. Carbon black (NEROX 3500, oil absorption: 50.3 ml/100 g, ORION carbon Co.) 140 g was added to the solution, stirred for 30 minutes at 5,000 rpm, and pre-dispersed, and then dispersed using a bead mill for 10 passes to obtain a carbon black dispersion. It was prepared.

(2) Preparation of ink composition

After mixing 25 parts by weight of the carbon black dispersion with 57.3 parts by weight of an epoxy resin, 2.5 parts by weight of a surfactant, 8 parts by weight of a photopolymerization initiator, and 7.2 parts by weight of a butyl cellosolve, the mixture was stirred to prepare an ink composition.

Example 2

A carbon black dispersion and an ink composition were prepared in the same manner as in Example 1, except that the dispersant shown in Table 1 below was used.

<Comparative Examples 1 to 7: Preparation of carbon black dispersion and ink composition>

Comparative Example 1

Without using the dispersing agent, except for adding 140 g of carbon black (NEROX 3500, oil absorption: 50.3 ml/100 g, ORION carbon) to 560 g of a 4:6 mixture of epoxy resin and butyl cellosolve, Example 1 and Similarly, a carbon black dispersion and an ink composition were prepared.

Comparative Example 2

A carbon black dispersion and an ink composition were prepared in the same manner as in Example 1, except that 186.7 g of the dispersant shown in Table 1 was dissolved in 373.3 g of a 4:6 mixture of an epoxy resin and butyl cellosolve.

Comparative Example 3

A carbon black dispersion and an ink composition were prepared in the same manner as in Example 1, except that the dispersant shown in Table 1 below was used.

Comparative Example 4

A carbon black dispersion and an ink composition were prepared in the same manner as in Example 1, except that the dispersant shown in Table 1 below was used.

Comparative Example 5

A carbon black dispersion and an ink composition were prepared in the same manner as in Example 1, except that the dispersant shown in Table 1 below was used.

Comparative Example 6

A carbon black dispersion and an ink composition were prepared in the same manner as in Example 1, except that the dispersant shown in Table 1 below was used.

Comparative Example 7

A carbon black dispersion and an ink composition were prepared in the same manner as in Example 1, except that 70 g of the dispersant shown in Table 1 was dissolved in 490 g of a 4:6 mixture of an epoxy resin and butyl cellosolve.

Dispersants of Examples and Comparative Examples division product name Solid content
(weight%) Molecular Weight
(g/mol) Polyvinyl butyral repeat unit
(weight%) Polyvinyl acetate repeating unit
(weight%) Polyvinyl alcohol repeating unit
(weight%) Example 1 B30T 100 42,900 57.5 2.6 39.9 Example 2 B20H 100 40,900 66.1 2.7 31.2 Comparative Example 2 BYK-161 30 - - - - Comparative Example 3 BYK-9150 100 - - - - Comparative Example 4 BX-L 100 40,300 44.8 1.7 53.5 Comparative Example 5 B30HH 100 105,000 73.7 4.2 22.2 Comparative Example 6 B14S 100 27,000 67 5.5 27.5 Comparative Example 7 B30T 100 42,900 57.5 2.6 39.9

In Table 1, the molecular weight is 0.1% by weight of the dispersant in Table 1 in tetrahydrofuran (tetrahydrofuran) by passing a solution through a syringe filter (0.02㎛) to remove foreign substances, and then adding 100µl to Agilent's 1200 product It was measured. The solvent used at this time is tetrahydrofuran, and was measured using a PLmixedB column at a rate of 40° C. and 1 ml/min. In addition, in Table 1, polyvinyl butyral repeat units, polyvinyl acetate repeat units, and polyvinyl acetate The content of the alcohol repeating unit was measured by using Bruker AVANCE IIIHD 700MHz NMR (1H) in a solution mixed at room temperature for 4 hours with 25 mg of the dispersant shown in Table 1 in 1 ml DMSO-d6. At this time, the measurement temperature was room temperature, and the number of scans was measured with a waiting time of 16 times and 3 seconds.

<Experimental Example: Measurement of physical properties of carbon black dispersion and ink composition obtained in Examples and Comparative Examples>

The physical properties of the carbon black dispersion and ink composition obtained in the above Examples and Comparative Examples were measured by the following methods, and the results are shown in Tables 2 and 3, respectively.

1. Viscosity (mPa·s)

For the carbon black dispersion and ink composition obtained in the above Examples and Comparative Examples, the viscosity was measured 5 times at 25°C and 50 rpm using a viscometer (TOKI SANGYO) to obtain an average value.

2. Viscosity change rate (%)

With respect to the ink composition obtained in the above Examples and Comparative Examples, the initial viscosity (a) and the viscosity (b) after one week at room temperature were measured by using a viscometer (TOKI SANGYO) to measure the viscosity five times at 25°C and 50 rpm. After that, an average value was obtained. And the viscosity change rate was calculated|required by following Formula (1).

[Equation 1]

Viscosity change rate (%) = (b-a) / a * 100

In Equation 1, a means the initial viscosity of the ink composition, and b means the viscosity after 1 week at room temperature of the UV curing ink composition.

3. Sedimentation speed (㎛/s)

For the ink composition obtained in the above Examples and Comparative Examples, 0.4 ml of the ink composition was loaded into a PA 110-134XY cell, and then settled by measuring 1,000 times at 25°C, 4,000 rpm, and a measurement interval of 60 seconds using LUMiSizer (LUM). The speed was determined.

4. Adhesive strength

With respect to the ink composition obtained in the above Examples and Comparative Examples, the ink composition was coated onto glass using No. 24 mayer bar (Samji Tech), and then cured for 3 minutes using a Black Light UV irradiation device (CANA tech). Ordered. Cross-cut grade was measured according to ASTM D3359 standard on the film formed through the curing.

Carbon black dispersion composition and experimental example results of Examples and Comparative Examples division Carbon black content (% by weight) SOP(%) Viscosity (mPa · s) Example 1 20 10 47.2 Example 2 20 10 36 Comparative Example 1 20 - >3,000 Comparative Example 2 20 40 >3,000 Comparative Example 3 20 20 22 Comparative Example 4 20 10 44 Comparative Example 5 20 10 96.8 Comparative Example 6 20 10 36.9 Comparative Example 7 20 50 >3,000

* >3,000: means a value measured over 3,000* SOP (Solid On Pigment): ratio of solid content of dispersant to carbon black solid content

Ink composition composition and experimental example results of Examples and Comparative Examples division Carbon black content
(weight%) Viscosity (mPa · s) Viscosity change rate (%) Sedimentation speed (㎛/s) Adhesion strength Example 1 5 20 6 8.8E-02 5B Example 2 5 20.3 7.6 9.9E-02 4B Comparative Example 1 - - - - - Comparative Example 2 - - - - - Comparative Example 3 5 25.2 19.5 2.5E+01 2B Comparative Example 4 5 21 26.2 1.1E-01 5B Comparative Example 5 5 24.1 34.9 9.9E-02 2B Comparative Example 6 5 23.1 13.9 5.1E-01 1B Comparative Example 7 5 52.8 gel 3.4E-02 5B

As shown in Table 2, in the case of Comparative Examples 1 to 2, the viscosity at the time of pre-dispersion was excessively increased, so that a carbon black dispersion could not be prepared, and an ink composition could also not be prepared. , Comparative Example 3 and the ink composition of Comparative Example 6 has a large viscosity change rate, the sedimentation rate is fast, the adhesion strength was measured low. The ink composition of Comparative Example 4 had a high adhesive strength, but a large rate of viscosity change and a fast sedimentation rate. The ink composition of Comparative Example 5 had a very large viscosity change rate and low adhesive strength. The ink composition of Comparative Example 7 had too high a viscosity that the composition gelled when measuring the rate of viscosity change, making it difficult to secure stability.

Claims (15)

Vinyl acetal repeating units 46 wt% to 73 wt%, vinyl ester repeating units 0.1 wt% to 5 wt% and vinyl alcohol repeating units 26 wt% to 52 wt%; Pigment; Photo-curable resins; And an organic solvent;
The photocurable resin and the organic solvent are contained in a weight ratio of 1:1.2 to 1:3,
The organic solvents are methyl ethyl ketone, a kind of ketone of cyclohexanone; aromatic hydrocarbons of toluene, xylene, and tetramethyl benzene; cellosolve, methyl cellosolve, propylene glycol monomethyl ether, glycol ethers of propylene glycol ethyl ether; ethyl acetate , Acetic acid esters of butyl acetate and cellosolve acetate; alcohols of ethanol and propano; aliphatic hydrocarbons of pentane, octane and decane; petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, absorbent naphtha, petroleum solvents It includes at least one selected from,
The pigment is CI pigment yellow 1, 3, 12, 13, 14, 15, 16, 17, 20, 24, 31, 53, 83, 86, 93, 94, 109, 110, 117, 125, 128, 137 , Yellow pigments of 138, 139, 147, 148, 150, 153, 154, 166, 173, 194, 214; Brown pigments of CI pigment orange 13, 31, 36, 38, 40, 42,43, 51, 55, 59, 61, 64, 65, 71, 73; CI Pigment Red 9, 97, 105, 122, 123, 144, 149, 166, 168, 176, 177, 180, 192, 209, 215, 216, 224, 242, 254, 255, 264, 265 red pigment ; CI pigment blue 15, 15: 3, 15: 4, 15: 6, 60 blue pigment; Violet pigments of CI pigment violet 1, 19, 23, 29, 32, 36, 38; Green pigment of CI pigment green 7, 36, 58; Color pigments of CI pigment brown 23, 25; CI pigment black 1, 7, carbon black, titanium black, contains at least one selected from the group consisting of black pigments of iron oxide,
The vinyl acetal repeating unit includes at least one selected from the group consisting of a vinyl butyral repeating unit, a vinyl isobutyral repeating unit, a vinyl propyral repeating unit, a vinyl acetal repeating unit, and a vinyl foam repeating unit,
The vinyl ester repeating unit includes a repeating unit represented by the following Chemical Formula 2,
The vinyl alcohol repeating unit includes a repeating unit represented by the following Chemical Formula 4, a photocurable pigment dispersion:
[Formula 2]

In the above Chemical Formula 2, R is hydrogen or a linear or branched alkyl group having 1 to 20 carbon atoms,
[Formula 4]

.
According to claim 1,
The photocurable resin comprises a photocurable monomer and oligomer, a photocurable pigment dispersion.
According to claim 1,
The photo-curable resin is an epoxy-based resin, oxetane-based resin, vinyl ether-based resin, (meth) acrylate-based resin and unsaturated polyester-based resin comprising at least one selected from the group consisting of, photocurable pigment dispersion.
According to claim 1,
The photocurable pigment dispersion has a pigment content of 10 to 40% by weight relative to the photocurable pigment dispersion.
According to claim 1,
A photocurable pigment dispersion comprising 5 parts by weight to 40 parts by weight of a vinyl-based copolymer based on 100 parts by weight of the pigment.
According to claim 1,
The photocurable pigment dispersion has a content of 10 to 40% by weight of the photocurable resin relative to the photocurable pigment dispersion.
According to claim 1,
The pigment is a photocurable pigment dispersion comprising carbon black having an oil absorption of 10 ml/100 g to 200 ml/100 g.
According to claim 1,
The vinyl ester repeating unit includes at least one selected from the group consisting of a vinyl acetate repeating unit, a vinyl formate repeating unit, a vinyl propionate repeating unit, a vinyl butyrate repeating unit, and a vinyl caprate repeating unit, a photocurable pigment dispersion. .
According to claim 1,
A photocurable pigment dispersion having a weight average molecular weight of 1,000 g/mol to 80,000 g/mol of the vinyl-based copolymer.
According to claim 1,
A photocurable pigment dispersion having a viscosity measured at 25°C of 1,500 mPa · s or less.
The photocurable pigment dispersion of claim 1; Photo-curable resins; An organic solvent and a photoinitiator; containing, photocurable ink composition.
The method of claim 11,
The content of the pigment with respect to the photo-curable ink composition is 0.1% to 10% by weight, a photo-curable ink composition.
The method of claim 11,
The photocurable ink composition, the content of the photocurable resin is 50% to 80% by weight relative to the photocurable ink composition.
The method of claim 11,
The photocurable ink composition has a viscosity of 30 mPa · s or less at 25°C.
The method of claim 11,
A photocurable ink composition having an adhesive strength to glass of 4B or more as measured by ASTM D3359.