JP6864748B2 - Inkjet printing composition and inkjet printed steel sheet using it - Google Patents

Description

The present invention relates to an inkjet print composition and an inkjet printed steel sheet using the same, and more particularly to an inkjet print composition capable of easily realizing a metallic texture and an inkjet printed steel sheet using the same.

Since the inkjet printing technology can realize various patterns and images, the market demand is expanding, and the demand for realizing patterns having various textures is increasing. In order to realize a metallic texture, metal particles must be mixed with the ink to achieve the metallic texture, and solvent-based inks having a metallic texture have been developed and put into practical use at present. However, solvent-based inks have problems such as VOC emission, discoloration and deformation of materials due to thermosetting, and increase in process cost, and development of an ultraviolet curable ink is required.

However, with solvent-free UV curable ink, it is not easy to dissolve the dispersant, and it is difficult to prevent the precipitation of metal powder with low viscosity and high specific gravity of the inkjet ink itself, so a metallic texture is realized. The reality is that it is difficult to do.

One of various objects of the present invention is to provide an inkjet printing composition capable of easily realizing a metallic texture and an inkjet printed steel sheet using the same.

One aspect of the present invention provides a composition for inkjet printing, which comprises polymer particles having a large number of pores and having a metal thin film formed on the surface.

Another aspect of the present invention is an inkjet printed steel sheet including a base steel sheet and a coating layer containing polymer particles formed on the surface of the base steel sheet, having a large number of pores, and having a metal thin film formed on the surface. I will provide a.

As one of the various effects of the present invention, the composition for inkjet printing according to the present invention has an advantage that a metallic texture can be easily realized.

It is a photograph which observed the polymer particle which formed the metal thin film on the surface. It is a photograph which observed the appearance of the inkjet printed steel sheet manufactured according to one Embodiment of this invention.

Hereinafter, the composition for inkjet printing, which is one aspect of the present invention, will be described in detail.

The composition for inkjet printing, which is one aspect of the present invention, contains polymer particles having a large number of pores and a metal thin film formed on the surface thereof.

As described above, conventionally, in order to realize a metallic texture in an inkjet printed steel sheet, metal particles have been simply mixed with the composition for inkjet printing. However, in the case of solvent-based inks, apart from the fact that metal particles can be dispersed in the composition by adding a dispersant, in the case of solvent-free UV-curable inkjet print compositions. Not only is it not easy to dissolve the dispersant, but it is also not easy to prevent the precipitation of metal powder having a low viscosity and a large specific gravity of the ink itself. There was a problem that it was difficult.

Therefore, the present inventors changed the idea and instead of adding the metal particles themselves to the composition for inkjet printing, formed a metal thin film on the surface of the polymer particles having a small specific gravity, and thus formed the metal thin film. The polymer particles in which the above was formed were added to the composition for inkjet printing.

However, it was confirmed that when a metal thin film is formed on the surface of a normal polymer, the effect of preventing precipitation by reducing the specific gravity of the metal-containing particles is not sufficient. Therefore, the present inventors have confirmed that the object of the present invention can be effectively achieved by forming a metal thin film on the surface of polymer particles having a large number of pores.

On the other hand, in order to further maximize the effect of the present invention, it is more preferable to form a metal thin film on the surface of the polymer particles having cavities formed therein. This is because the specific gravity of the metal-containing particles is remarkably lowered and the dispersibility of the metal-containing particles is remarkably improved.

According to an unrestricted example, the average particle size of the polymer particles having the metal thin film formed on the surface can be 50 to 2000 nm. If the average particle size is less than 50 nm, the effect of achieving a metallic texture due to diffused reflection of the particles is reduced, while if it exceeds 2000 nm, the head nozzle is clogged and the jetting property is lowered. Here, the average particle size means the average circular diameter of the polymer particles on which the metal thin film is formed.

According to an unrestricted example, the ratio of the volume of the cavity to the volume of the polymer particles on which the metal thin film is formed can be 8: 1-8: 7. If the volume of the cavity is too small and the ratio is less than 8: 1, the effect of reducing the specific gravity due to the formation of the cavity is insufficient, while if the ratio exceeds 8: 7, due to an external impact. The polymer particles may easily crack or deform.

In the present invention, the structure and specific type of the polymer particles having a large number of pores are not particularly limited, but according to an example without limitation, a core-shell structure can be obtained, and more specifically, hydrophilicity. It can include a core layer polymer polymerized from a monomer containing an acid monomer and at least one or more cell layer polymers surrounding the core layer polymer. At this time, a cavity can be formed inside the core layer polymer.

The core layer polymer is spherical nanoparticles that form micelles and is preferably an amphipathic polymer because of its affinity with the cells surrounding the core, more specifically the core. The layer polymer is preferably a copolymer of a hydrophilic acid monomer and an ethylenically unsaturated monomer.

The hydrophilic acid monomer is not particularly limited, and for example, ethylenically unsaturated carboxylic acid, monoalkyl ester of unsaturated carboxylic acid, vinyl benzoic acid and the like can be used.

The ethylenically unsaturated monomer is not particularly limited, but is, for example, an aromatic vinyl monomer such as styrene, methylstyrene, halogenated styrene, or divinylbenzene; methyl (meth) acrylate, ethyl (meth). ) (Meta) acrylic acid esters such as acrylates, butyl (meth) acrylates, 2-ethylhexyl (meth) acrylates, lauryl (meth) acrylates; diene monomers such as butadiene, isoprene; N-butoxymethyl ( (Meta) acrylamides such as meta) acrylamide and derivatives thereof; vinyl carboxylic acid esters such as vinyl acetate; vinyl halides such as vinyl chloride; vinylidene halides such as vinylidene chloride; or vinylpyridine can be used. , Two or more kinds of the above-mentioned monomers can be used.

The cell layer polymer can be used without limitation as long as it can maintain a particle shape, for example, a spherical shape or a tubular shape during the production process. For example, the cell layer polymer surrounds the intermediate layer polymer which is a copolymer of a hydrophilic acid monomer and an ethylenically unsaturated monomer, and the intermediate layer polymer, and is polymerized from the hydrophobic monomer. It can be formed with a two-layer structure of an outer layer polymer, and in some cases, can contain more functional layers.

Here, the types of the hydrophilic acid monomer and the ethylenically unsaturated monomer are as described above. On the other hand, the hydrophobic monomer is an aromatic vinyl monomer such as styrene, methylstyrene, halogenated styrene, or divinylbenzene; methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, and the like. (Meta) acrylic acid esters such as 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate; diene-based monomers such as butadiene, isoprene; vinyl carboxylic acid esters such as vinyl acetate; vinyl chloride Such as vinyl halide; vinyl halide such as vinylidene chloride; or vinylpyridine and the like can be used.

On the other hand, in the present invention, the method for producing polymer particles having a large number of pores as described above is not particularly limited, and for example, emulsion polymerization, radical polymerization, ion polymerization, suspension polymerization, urethane polymerization, sol-gel. Any of the commonly known polymerization methods, such as polymerization, can be used. If it is produced by emulsion polymerization, the following method can be used as a preferable example.

The core layer polymer uses distilled water as a reaction medium, emulsifies a monomer capable of emulsion polymerization, and if necessary, a chain transfer agent with a surfactant, and then uses a water-soluble initiator. It can be added to initiate the reaction and synthesize. More specifically, an emulsion obtained by emulsifying a monomer with a surfactant is emulsified by an ultrasonic emulsifier and then charged into a reactor, and nitrogen is charged to maintain the inside of the reactor in a nitrogen atmosphere. Then, after raising the temperature of the reactor to 50 to 1000 ° C. using an oil bath, a water-soluble initiator is added to start the reaction, and the core layer polymer can be synthesized. ..

Here, the monomers capable of emulsion polymerization are as described above. On the other hand, as the surfactant, an anionic surfactant such as sodium lauryl sulfate, tetradecyl trimethylammonium bromide, hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium bromide. Cationic surfactants such as trimethylammonium chloride and nonionic surfactants such as nonyl phenyl ether can be used. In particular, in the present invention, when a coating agent is used, a cationic surfactant can be preferably used in order to improve the adhesiveness with the substrate. The reaction ratio of the monomer to the surfactant is preferably 1: 0.001 to 0.2 by weight, more preferably 1: 0.005 to 0.1. If the reaction ratio of the monomer to the surfactant is out of the above range, there is a problem that the state of the emulsion becomes unstable.

Further, examples of the water-soluble initiator include persulfate-based initiators such as ammonium persulfate, sodium persulfate, and potassium persulfate, and 4,4-azobis (4-cyano). Azo-based initiators such as valeric acid) (4,4-Azobis (4-cyanovaleric acid)), azobis (2-amidinopropane) dihydrochloride (Azobis (2-amidinopropane) dihydrochloride) can be used and used. The amount may be 0.1 to 5 parts by weight, preferably 0.5 to 2 parts by weight, based on 100 parts by weight of the monomer.

Further, as the chain transfer agent, those usually used in emulsion polymerization can be used.

Further, in order to form an intermediate layer before the stage of forming the outer layer polymer, for example, it is a copolymer of an aqueous acid monomer and an ethylenically unsaturated monomer in the presence of the core layer polymer. A step of forming an intermediate layer polymer can be further included. The monomer of the outer layer is as described above, and the emulsion polymerization method described above can be used as the polymerization method.

On the other hand, the cavities inside the particles can be formed by a method in which an alkaline substance is mixed with the core layer polymer to expand the core particles. In the present invention, the type of alkaline substance is not particularly limited, but for example, ammonia, ethanolamine, triethanolamine, 5-amino-1-pentanol, diethanolamine, propylamine, dipropylamine and the like can be used. The size of the cavity can be appropriately adjusted according to the amount of the alkaline substance to be mixed and the mixing time.

In the present invention, the specific type of the metal thin film formed on the surface of the polymer particles having a large number of pores is not particularly limited. For example, the metal forming the metal thin film is Zn, Mg, Au, Ag, etc. It can be one or more selected from the group consisting of Cu and Al. On the other hand, the metal thin film can also be an ordinary stainless (STS) thin film.

Further, in the present invention, the thickness of the metal thin film is not particularly limited, but to give an example without limitation, the thickness of the metal thin film can be 10 to 200 nm. If the average thickness of the metal thin film is less than 10 nm, the effect of achieving a metallic texture may not appear, while if it exceeds 200 nm, not only the process cost increases excessively, but also the specific gravity and particles Dispersibility and jetting property may decrease due to the increase in size.

Further, in the present invention, the method of forming a metal thin film on the surface of polymer particles having a large number of pores is not particularly limited, but an example without limitation is electroplating or physical vapor deposition (PVD, Physical Vapor Deposition). , Aerosol Deposition, dipping and the like.

In the present invention, the content of the polymer particles on which the metal thin film is formed contained in the composition for inkjet printing is not particularly limited, but according to an example without limitation, 5 per 100 parts by weight of the composition for inkjet printing. It can contain up to 50 parts by weight. If the content is less than 5 parts by weight, the effect of realizing the metallic texture may not appear, while if it exceeds 50 parts by weight, the metal particles may not adhere to the printed surface and may be peeled off. There is. In one embodiment of the present invention, as a more preferable range of the content of the polymer particles on which the metal thin film is formed, 20 to 40 parts by weight can be included with respect to 100 parts by weight of the composition for inkjet printing.

In the present invention, the specific types of the components that can be contained in the composition for inkjet printing are not particularly limited except for the polymer particles on which the metal thin film is formed, and the composition for ordinary solvent-based inks and the like. It can be composed of the components contained in the composition for ultraviolet curable ink. However, as described above, the solvent-based ink has problems due to VOC emission, discoloration and deformation of the material due to thermosetting, an increase in process cost, etc. Therefore, the following is a composition for ultraviolet curable ink. The remaining components other than the polymer particles on which the metal thin film is formed will be described in detail on the premise of.

"Acrylic monomer"
The acrylic monomer participates in the photocuring reaction and acts as a binder in the coating layer.

The acrylic monomer can be contained in an amount of 10 to 60 parts by weight, preferably 20 to 50 parts by weight, based on 100 parts by weight of the composition for inkjet printing. If the content of the acrylic monomer is too small, the viscosity becomes excessive and it becomes difficult to apply the inkjet ink to the steel material. On the contrary, if the content of the acrylic monomer is too large, the overall physical characteristics of the coating film may be adversely affected.

According to one example, the acrylic monomer can be one or a mixture of one or more of a monofunctional acrylic monomer, a bifunctional acrylic monomer, and a polyfunctional acrylic monomer.

Further, according to one example, the monofunctional acrylic monomer used as the acrylic monomer is one or a mixture of two or more selected from the group consisting of alkyl acrylates, allyl acrylates, alkoxy acrylates, and tetrahydrofurfuryl acrylates. There can be.

Further, according to one example, the bifunctional acrylic monomer used as the acrylic monomer can be one kind or a mixture of two or more kinds selected from the group consisting of tripropylene glycol diacrylate and hexanediol diacrylate. ..

Further, according to one example, the polyfunctional acrylic monomer used as the acrylic monomer may be one kind or a mixture of two or more kinds selected from the group consisting of trimethylpropane ethoxylate triacrylate and trimethylpropane triacrylate. it can.

"Acrylic oligomer"
Acrylic oligomers also participate in the photocuring reaction and play a role as a binder in the coating layer. Here, the acrylic oligomer means an oligomer having at least one acrylic group in the molecule.

The acrylic oligomer can be contained in an amount of 10 to 40 parts by weight, preferably 10 to 30 parts by weight, based on 100 parts by weight of the composition for inkjet printing. If the content of the acrylic oligomer is less than 10 parts by weight, the adhesiveness, processability, solvent resistance, etc. deteriorate, while if it exceeds 30 parts by weight, the viscosity becomes excessively increased and injection becomes difficult. This makes it difficult to apply the inkjet ink.

According to one example, acrylic oligomers include epoxy acrylates, urethane-based modified epoxy acrylates, urethane acrylates, polyester acrylates, polyether acrylates, acrylic acrylates, silicon acrylates, melamine acrylates, acrylic acrylates, polythiol acrylate derivatives, and polythiol spiroacetals. It can be one or a mixture of two or more selected from the group consisting of acrylates.

"Light initiator"
The photoinitiator serves to initiate the photocuring reaction. In the present invention, the content of the photoinitiator is not particularly limited, but it can be contained in an amount of 1 to 10 parts by weight with respect to 100 parts by weight of the composition for inkjet printing. If it is less than 1 part by weight, the photocuring reaction may not sufficiently occur, and if it exceeds 10 parts by weight, the physical properties of the coating layer may be deteriorated.

According to one example, the photoinitiator can be a benzophenone-based, diphenoxybenzophenone-based, anthraquinone derivative, xanthone derivative, thioxanthone derivative, or benzyl-based. In addition, initiators such as the currently commercially available photoinitiators Microure HP-8, Irgacure 819, Darocur TPO, and Microcure CP-4 can be used, but are not necessarily limited thereto.

"Other additives"
In addition to the above-mentioned components, the composition for inkjet printing of the present invention comprises a defoaming agent, a leveling agent, an adhesion enhancer, a stabilizer, an antioxidant, an ultraviolet absorber, a thermal polymerization inhibitor, a smoothing agent, a dispersant, and the like. It can contain 0.01 to 10 parts by weight of one or more additives selected from the group consisting of antistatic agents and silane coupling agents. When the additive is added within the above content range, the original effect of the additive can be exhibited without changing the physical properties of the coating film.

The defoaming agent is for removing air bubbles generated in the coating, and specific examples thereof include TEGO Airex 920, TEGO Airex 932, BYK 088, and BYK 1790.

The leveling agent is for improving the surface appearance and scratchability, and specific examples thereof include TEGO Glide 410, TEGO Glide 440, TEGO Rad 2250, BYK-UV 3500, and BYK-UV 3510. be able to.

The adhesion enhancer is for improving the adhesion with the base steel sheet, and specific examples thereof include acrylic phosphate-based adhesion enhancers such as hydroxyethylacryloyl phosphate or hydroxyethyl methacrylate phosphate. ..

Stabilizers are intended to facilitate storage, and specific examples include phenolic antioxidants, alkylated monophenols, alkylthiomethylphenols, hydroquinones, alkylated hydroquinones, tocopherols, etc. Hydroxyylated thiodiphenyl ether, alkylidenebisphenol, O-, N- and S-benzyl compounds, hydroxybenzylated malonate, aromatic hydroxybenzyl compounds, triazine compounds, amine-based antioxidants, allylamine, diallylamine, polyallylamine, Examples thereof include acylaminophenol, oxamide, metal inactivator, phosphite, phosphonite, benzylphosphonate, ascorbic acid, hydroxylamine, nitron, thiocinergist, benzofuranone, or indolinone. In addition, BASF products such as the currently commercially available stabilizers Tinuvin 292, Tinuvin 144 or Tinuvin 622LD, and Sanol LS-770, Sanol. Sankyo products such as LS-765 (sanol LS-765), Sanol LS-292 (sanol LS-292) or Sanol LS-744 (sanol LS-744) can be used.

The antioxidant is for preventing an oxidation reaction and as a result facilitating storage, and specific examples thereof include Irganox 1010, Irganox 1035, and Irganox. BASF products such as 1076 (Irganox 1076) or Irganox 1222 (Irganox 1222) can be mentioned.

The ultraviolet absorber is for assisting UV absorption in the photocuring reaction to increase the efficiency of the photocuring reaction, and specific examples thereof include Tinuvin P, Tinuvin 234, and Tinubin 320. BASF products such as (Tinuvin 320) or Tinuvin 328 (Tinuvin 328) and Sumisorb 110, Sumisorb 130, Sumisorb 140, Sumisorb 220, Sumisorb 220. 250), Sumisorb 320, Sumisorb 400, and other Sumitomo products.

The thermal polymerization inhibitor is for increasing the efficiency of the photocuring reaction by preventing the reaction from being terminated by a side reaction due to heat, and specific examples thereof include HQ, THQ, and HQMME. it can.

The smoothing agent and the dispersant are for smoothing dispersion in a solvent, and products of ordinary paint additive manufacturers such as BYK, TEGO and EFKA can be selected and used.

The antistatic agent is added for antistatic in the photocuring reaction, and specific examples thereof include polyoxyethylene alkyl ether type, polyoxyethylene amine type, glycerin or sorbitol fatty phase ester type. Examples thereof include nonionic systems and anionic systems such as alkyl sulfonates, alkyl benzene sulfonates, alkyl sulfates, and alkyl phosphates, or quaternary ammonium salts or mixtures thereof.

The silane coupling agent is for improving the adhesive strength of the composition for inkjet printing of the present invention, and specific examples thereof include methacryloxypropyltrimethoxysilane, gamma-methacryloxypropylethoxysilane, and gamma-. Chloropropylmethoxysilane, vinyltriethoxysilane, vinyltris (beta-methoxyethoxy) silane, vinyltriacetoxysilane, gamma-glycidoxypropyltrimethoxysilane, gamma-glycidoxypropyltriethoxysilane, beta- (3,4) -Epoxycyclohexyl) ethyltrimethoxysilane, vinyltrichlorosilane, gamma-mercaptopropylmethoxysilane, gamma-aminopropyltriethoxysilane, N-beta- (aminoethyl) -gamma-aminopropyltrimethoxysilane or a mixture thereof. be able to.

Hereinafter, the inkjet printed steel sheet, which is another aspect of the present invention, will be described in detail.

The inkjet printed steel sheet, which is another aspect of the present invention, comprises a base steel sheet and a coating layer containing polymer particles formed on the surface of the base steel sheet, having a large number of pores, and having a metal thin film formed on the surface. Including.

In the present invention, the type of the base steel sheet is not particularly limited, but to give an example without limitation, the base steel sheet is a cold-rolled steel sheet; a hot-rolled steel sheet; a galvanized steel sheet; an aluminum-plated steel sheet; cobalt, molybdenum, tungsten, nickel, titanium. , Manganese, iron, magnesium, tin, copper, or a galvanized steel sheet containing a mixture thereof; or an aluminum alloy plate containing silicon, copper, magnesium, iron, manganese, titanium, zinc, or a mixture thereof. it can.

In order to produce the inkjet printed steel sheet of the present invention, a coating layer can be formed by coating the surface of the steel sheet with the above-mentioned composition for inkjet printing and curing it, and the coating layer is formed on the surface of the base steel sheet. In the case, a metallic texture can be realized. The components that can be contained in the composition and their composition range are as described above.

In the present invention, the thickness of the coating layer is not particularly limited, but to give an example without limitation, it can be 0.1 to 15 μm. If the thickness is less than 0.1 μm, the metallic texture may not be sufficiently realized, while if it exceeds 15 μm, the printed layer after printing may be peeled off or uncured may occur. is there.

FIG. 2 is a photograph of an observation of the appearance of an inkjet printed steel sheet manufactured according to an embodiment of the present invention. With reference to FIG. 2, it can be visually confirmed that the metallic texture can be easily realized in spite of using the ultraviolet curable ink.

[Manufacturing of polymer particles, metal thin film coating]
The polymer particles were continuously produced via an emulsification polymerization method. A polymer cell was synthesized using a carboxylic acid latex core as a seed and methyl methacrylate and styrene as main components. In order to form a cavity inside the polymer particles, the seed substance was neutralized with ammonia, the polymer particles were produced, and then the target metal was sputtered in a vacuum chamber to produce a thin film.

[Test criteria]
The jetting property was determined based on whether or not the ink composition could be ejected from the inkjet head. That is, if the nozzle is clogged from the beginning and it is impossible to eject the ink composition, it is judged as x, and if the nozzle is clogged during the work although it is ejected at the beginning, the nozzle is clogged from the beginning to the end. The case where the ink can be discharged without any problem was judged as ◯.

The metal texture was evaluated by comparing the appearance based on the galvanized steel sheet. That is, when the printed steel sheet as shown in FIG. 2 has the same metallic texture as the galvanized steel sheet, it was judged as ◯, and when it was not, it was judged as x.

The degree of curing was evaluated by rubbing a cloth with MEK with a force of 1 kgf 50 times to see if the base material was exposed, and if the base material was exposed, it was judged to be x, and if not, it was judged to be ○.

The adhesion was based on the ISO 2409 paint adhesion test method, and one line was drawn vertically and horizontally on the test piece so that the interval was 1 mm, and cellophane adhesive tape was attached on it. .. Later, it was peeled off, and the adhesive strength was evaluated by the number of remaining pieces among the coated surfaces separated into 100 pieces. If 80% or more of all the pieces were dropped, it was judged as x, and if not, it was judged as ○.

As can be confirmed from Table 1 above, in the case of the invention example satisfying the condition of the present invention, excellent jetting property is exhibited, and also excellent curability while exhibiting a metallic texture in terms of the physical characteristics of the coating film. It showed adhesion.

However, in the case of Comparative Example 1, the thickness of the metal thin film formed on the polymer particles was thin and did not show a sufficient metallic texture, and in Comparative Example 2, the coating was thick and the degree of curing was poor. It was enough. Further, in Comparative Example 3, the proportion of the polymer particles contained in the composition for inkjet printing was high, and the sufficiently formed coating film did not have sufficient adhesion. Comparative Example 4 showed a result that the jetting property was insufficient in the case where the thickness of the metal thin film was a little thick, and Comparative Example 5 in which the thickness of the metal thin film was further thick was poor in jetting property. , The result that the coating film formation itself was impossible was shown. In Comparative Example 6, the content of the polymer particles in the inkjet composition was only 1% by weight, and it was difficult to obtain a metallic texture. Further, Comparative Example 7 is a case where the particle size of the polymer particles is as thick as 2200 nm, and in such a case, there is a problem in jetting property and a coating film is not formed.

Claims (13)

Has a large number of pores, the polymeric particles with a metal thin film formed on a surface seen including,
The average particle size of the polymer particles on which the metal thin film is formed is 50 to 2000 nm.
The thickness of the metal thin film is 10 to 200 nm, and the thickness of the metal thin film is 10 to 200 nm.
The polymer particles on which the metal thin film was formed were contained in an amount of 5 to 50 parts by weight with respect to 100 parts by weight of the entire composition.
The polymer particles are
A core layer polymer polymerized from a monomer containing a hydrophilic acid monomer,
An intermediate layer polymer comprising a copolymer of a hydrophilic acid monomer and an ethylenically unsaturated monomer surrounding the core layer polymer and
A composition for inkjet printing , which comprises an outer layer polymer which surrounds the intermediate layer polymer and is polymerized from a hydrophobic monomer. The composition for inkjet printing according to claim 1, wherein cavities are formed inside the polymer particles. The composition for inkjet printing according to claim 2, wherein the ratio of the volume of the cavity to the volume of the polymer particles on which the metal thin film is formed is 8: 1 to 8: 7. The composition for inkjet printing according to any one of claims 1 to 3, wherein the metal forming the metal thin film is at least one selected from the group consisting of Zn, Mg, Au, Ag, Cu and Al. .. The composition for inkjet printing according to any one of claims 1 to 4 , wherein the metal thin film is a stainless steel thin film. Claims 1 to 5 further include 10 to 60 parts by weight of an acrylic monomer, 10 to 40 parts by weight of an acrylic oligomer, and 1 to 10 parts by weight of a photoinitiator with respect to 100 parts by weight of the total composition. The composition for inkjet printing according to any one of the items. The composition for inkjet printing according to claim 6 , wherein the acrylic monomer is one or a mixture of one or more of a monofunctional acrylic monomer, a bifunctional acrylic monomer, and a polyfunctional acrylic monomer. Stuff. The acrylic oligomer comprises an epoxy acrylate, a urethane-based modified epoxy acrylate, a urethane acrylate, a polyester acrylate, a polyether acrylate, an acrylic acrylate, a silicon acrylate, a melamine acrylate, an acrylic acrylate, a polythiol acrylate derivative, and a polythiol spiroacetal-based acrylate. The composition for inkjet printing according to claim 6 or 7 , which is one kind or a mixture of two or more kinds selected from the group. The composition for inkjet printing according to any one of claims 6 to 8, wherein the photoinitiator is a benzophenone-based, diphenoxybenzophenone-based, anthraquinone derivative, xanthone derivative, thioxanthone derivative, or benzyl-based. The composition is a group consisting of a defoaming agent, a leveling agent, an adhesion enhancer, a stabilizer, an antioxidant, an antistatic agent, an ultraviolet absorber, a thermal polymerization inhibitor, a smoothing agent, a dispersant, and a silane coupling agent. The composition for inkjet printing according to any one of claims 6 to 9, further comprising one or more additives selected from. And the base steel sheet, is formed on the surface of the base steel sheet has a plurality of pores, see contains a coating layer containing a polymer particles with a metal thin film formed on the surface,
The coating layer has a thickness of 0.1 to 15 μm and has a thickness of 0.1 to 15 μm.
The average particle size of the polymer particles on which the metal thin film is formed is 50 to 2000 nm.
The thickness of the metal thin film is 10 to 200 nm, and the thickness of the metal thin film is 10 to 200 nm.
The polymer particles on which the metal thin film was formed were contained in an amount of 5 to 50 parts by weight with respect to 100 parts by weight of the entire composition.
The polymer particles are
A core layer polymer polymerized from a monomer containing a hydrophilic acid monomer,
An intermediate layer polymer comprising a copolymer of a hydrophilic acid monomer and an ethylenically unsaturated monomer surrounding the core layer polymer and
An inkjet printed steel sheet containing the outer layer polymer that surrounds the intermediate layer polymer and is polymerized from a hydrophobic monomer. The base steel sheet is a cold-rolled steel sheet; a hot-rolled steel sheet; a galvanized steel sheet; an aluminum-plated steel sheet; a plated steel sheet containing cobalt, molybdenum, tungsten, nickel, titanium, manganese, iron, magnesium, tin, copper or a mixture thereof; The inkjet printed steel sheet according to claim 11 , which is an aluminum alloy sheet to which silicon, copper, magnesium, iron, manganese, titanium, zinc or a mixture thereof is added. The inkjet printed steel sheet according to claim 11 or 12 , wherein the coating layer contains 5 to 50 parts by weight of polymer particles on which the metal thin film is formed.

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