JP2017140751A - Inkjet printing apparatus using photopolymerizable ink and cured product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently perform a photopolymerizable ink showing good adhesion to various substrates in an inkjet printing method which can be compactly and easily applied without using a large-scale facility such as spray coating. Provision of an inkjet printing device equipped with a curing means. An apparatus for printing using a photopolymerizable ink containing at least n-pentyl methacrylate and a polymer component, comprising at least an ultraviolet irradiation means, and using ultraviolet light in the UVA region (wavelength: 320 nm to 390 nm). An inkjet printing apparatus capable of raising the temperature of a stainless steel plate having a thickness of 0.5 mm from 23 ° C. to 36 ° C. or higher when the integrated light amount is 1.8 J / cm2 in one light irradiation. [Selection diagram] None

Description

  The present invention relates to an inkjet printing apparatus using a photopolymerizable ink and a cured product.

Photopolymerizable inkjet inks using (meth) acrylic acid esters are widely known (Patent Document 1, etc.). It is also known that various functions can be imparted to the coating film by blending a polymer component with the photopolymerizable ink (Patent Document 2 and the like).
One of the advantages of blending polymer components is that the liquid is difficult to permeate, and it is possible to ensure sufficient adhesion even for plastic materials and other substrates that are relatively smooth and difficult to ensure adhesion of the coating film. There is. However, when a polymer component is blended with a photopolymerizable inkjet ink, the increase in viscosity associated with the blending of the polymer component is significant, so discharge is possible unless a sufficiently low-viscosity monomer material is used. It is difficult to reduce the viscosity within a certain range.
However, many of the monomers used in conventional photopolymerizable ink-jet inks are toxic. Particularly, (meth) acrylic acid esters that are inexpensive and can be easily procured and have a sufficiently low viscosity are not suitable for the skin. Most skin sensitivities that cause allergies when touched are highly toxic. Therefore, there is no problem in skin sensitivity, and it is difficult to obtain a photopolymerizable inkjet ink having a sufficiently low viscosity that can be discharged at room temperature even when a polymer component is blended, and there has been no effective solution. . Therefore, the present inventors have intensively studied and found the ink according to Patent Document 3. However, it has been necessary to study a method for more efficiently curing and drying the ink.

  The present invention is a photopolymerizability that shows good adhesion to various substrates including a polymer component in ink-jet printing that can be applied in a small and simple manner without using large-scale equipment such as spray coating. An object of the present invention is to provide an ink jet printing apparatus provided with a means capable of efficiently curing ink.

The above problem is solved by the following invention 1).
1) An apparatus for printing using a photopolymerizable ink containing at least n-pentyl methacrylate and a polymer component, comprising at least an ultraviolet irradiation means, and one time by UV light in the UVA region (wavelength: 320 nm to 390 nm) An ink jet printing apparatus, wherein the temperature of a stainless steel plate having a thickness of 0.5 mm can be increased from 23 ° C. to 36 ° C. or more when the integrated light quantity is 1.8 J / cm ² in light irradiation.

  According to the present invention, light that exhibits good adhesion to various substrates including a polymer component in ink-jet printing that can be applied in a small and simple manner without using large-scale equipment such as spray coating. An ink jet printing apparatus provided with a means capable of efficiently curing a polymerizable ink can be provided.

It is the schematic which shows an example of the inkjet printing apparatus of this invention. It is the schematic which shows an example of the formation apparatus of the three-dimensional solid image which concerns on the inkjet printing apparatus of this invention. It is the schematic which shows the other example of the formation apparatus of the three-dimensional solid image which concerns on the inkjet printing apparatus of this invention. (A) It is the schematic which shows a mode that the ultraviolet-ray 4 is irradiated to the photopolymerizable ink 5 in the storage pool (accommodating part) 1, and the hardened layer 6 is formed on the movable stage 3. FIG. (B) It is the schematic which shows the state in which the hardened layer 6 became the predetermined shape. (C) It is the schematic which shows a mode that the movable stage 3 is fall | descended by predetermined height after the hardened layer 6 becomes a predetermined shape. (D) It is the schematic which shows a mode that the ultraviolet-ray 4 is irradiated to the photopolymerizable ink 5 in the storage pool (accommodating part) 1 until the hardened layer 6 becomes a predetermined shape, and the hardened layer 6 is laminated | stacked.

Hereinafter, the present invention 1) will be described in detail. However, since the following 2) to 5) are also included in the embodiment of the present invention 1), these will be described together.
2) The inkjet printing apparatus according to 1), wherein the temperature of the stainless steel plate can be increased from 23 ° C. to 43 ° C. or more.
3) The temperature of the said stainless steel plate can be raised from 23 degreeC to 54 degreeC or more, The inkjet printing apparatus as described in 1) characterized by the above-mentioned.
4) The photopolymerizable ink contains 1-hydroxycyclohexyl phenyl ketone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1, 2-dimethylamino-2- (4-methylbenzyl) 1 including at least one selected from -1- (4-morpholin-4-yl-phenyl) butan-1-one and bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide. The inkjet printing apparatus according to any one of 3) to 3).
5) A photopolymerizable ink containing at least n-pentyl methacrylate and a polymer component is applied onto a base material, and the ink is irradiated with ultraviolet light in a UVA region (wavelength: 320 nm to 390 nm) using an ultraviolet irradiation device. When the integrated light quantity is 1.8 J / cm ² in a single light irradiation, light irradiation is performed under irradiation conditions that can raise the temperature of a stainless steel plate having a thickness of 0.5 mm from 23 ° C. to 36 ° C. or more. The cured product produced.

  As described above, the inventors have found an ink that exhibits good adhesion to a substrate such as that of Patent Document 3. The feature of this ink is that it is composed only of materials that have no problem with regard to the toxicity of skin sensitivity, which has been a problem with existing photopolymerizable inks. Details of SI value indicating the degree of skin sensitivity Is as described in Patent Document 3. However, it has a factor that is difficult to cure because it contains a polymer component that is not involved in polymerization, in addition to the main component of methacrylic acid ester, which is generally considered to be less reactive than acrylic acid ester. . Therefore, in order to cure and dry the ink more efficiently, the inventors have focused on the ultraviolet irradiation device that is a curing light source, and have studied the effective use of the generated heat, resulting in the present invention.

The photopolymerizable monomer having negative skin sensitivity refers to a compound corresponding to at least one of the following (1) to (3).
(1) In the skin sensitivity test by the LLNA method (Local Lymph Node Assay), a compound having a Stimulation Index (SI value) of less than 3 indicating the degree of sensitivity (2) MSDS (Chemical Safety Data Sheet) A compound evaluated as “negative skin sensibility” or “no skin sensibility” (3) “Skin sensibility negative” or “skin in literature [eg Contact Dermatitis 8 223-235 (1982)] Compounds rated as “no sensitivity”

Regarding (1), for example, “Functional Materials”, September 2005, Vol. 25, no. 9, as shown in P55, when the SI value is less than 3, it is determined that the skin sensitivity is negative. The lower the SI value, the lower the skin sensitivity. Therefore, in the present invention, it is preferable to use a monomer having an SI value as low as possible, preferably less than 3, preferably 2 or less, more preferably 1.6 or less. .

  The photopolymerizable ink used in the present invention desirably has negative skin sensitization. Examples of monofunctional monomers that are negative in skin sensitivity and that can be easily procured include t-butyl methacrylate, n-pentyl methacrylate, and n-hexyl methacrylate. Similarly, polyfunctional monomers that are negative in skin sensitivity and that can be easily procured are glycerol dimethacrylate, tricyclodecane dimethanol dimethacrylate, diethylene glycol dimethacrylate, trimethylolpropane trimethacrylate (alkylene oxide). It may be a modified one).

In addition, even if a simple substance has some problems in skin sensitivity, or a compound whose skin sensitivity has not been confirmed, it can be used in addition to a negative skin sensitivity if necessary. Examples thereof include the following (meth) acrylates, (meth) acrylamides, and vinyl ethers.
Ethylene glycol di (meth) acrylate, hydroxypivalic acid neopentyl glycol di (meth) acrylate, γ-butyrolactone acrylate, isobornyl (meth) acrylate, formalized trimethylolpropane mono (meth) acrylate, polytetramethylene glycol di (meth) acrylate, trimethylolpropane (meth) acrylate benzoate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate _{[CH 2 = CH-CO- (OC} 2 H 4) n- OCOCH = CH ₂ (n≈9), (n≈14), (n≈23)], dipropylene glycol di (meth) acrylate, tripropylene glycol Koruji (meth) acrylate, polypropylene glycol di methacrylate _{[CH 2 = C (CH 3)} -CO- (OC 3 H 6) n-OCOC (CH 3) = CH 2 (n ≒ 7) ], 1,3 Butanediol diacrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, Tricyclodecane dimethanol diacrylate, propylene oxide modified bisphenol A di (meth) acrylate, polyethylene glycol di (meth) acrylate, dipentaerythritol hexa (meth) acrylate, (meth) acryloylmorpholine, 2-hydroxypropyl (meth) acrylic Ami , Propylene oxide modified tetramethylolmethane tetra (meth) acrylate, dipentaerythritol hydroxypenta (meth) acrylate, caprolactone modified dipentaerythritol hydroxypenta (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, pentaerythritol tetra (meth) Acrylate, trimethylolpropane triacrylate, ethylene oxide modified trimethylolpropane triacrylate, propylene oxide modified trimethylolpropane tri (meth) acrylate, caprolactone modified trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, tris ( 2-Hydroxyethyl) isocyanurate tri (meth) acryl Ethoxylated neopentyl glycol di (meth) acrylate, propylene oxide modified neopentyl glycol di (meth) acrylate, propylene oxide modified glyceryl tri (meth) acrylate, polyester di (meth) acrylate, polyester tri (meth) acrylate, Polyester tetra (meth) acrylate, polyester penta (meth) acrylate, polyester poly (meth) acrylate, N-vinylcaprolactam, N-vinylpyrrolidone, N-vinylformamide, polyurethane di (meth) acrylate, polyurethane tri (meth) acrylate, Polyurethane tetra (meth) acrylate, polyurethane penta (meth) acrylate, polyurethane poly (meth) acrylate, triethyleneglycol Divinyl ether, cyclohexanedimethanol divinyl ether, cyclohexanedimethanol monovinyl ether, hydroxyethyl vinyl ether, diethylene glycol monovinyl ether, diethylene glycol divinyl ether, dicyclopentadiene vinyl ether, tricyclodecane vinyl ether, benzyl vinyl ether, ethyl oxetane methyl vinyl ether, triethylene glycol di Vinyl ether, hydroxybutyl vinyl ether, ethyl vinyl ether, etc.

The ink used in the present invention preferably uses a photo radical polymerization initiator, and more preferably uses a photo radical polymerization initiator having negative skin sensitivity.
It is known that (meth) acrylic acid esters, (meth) acrylamides and derivatives thereof, and vinyl ether compounds also have ionic polymerizability. However, ionic polymerization initiators are generally expensive and generate slightly strong acids and strong alkalis even in the absence of light irradiation, so that acid and alkali resistance is provided in the ink supply path in the ink jet coating system. Special consideration is required. For this reason, there is a restriction on the selection of members constituting the inkjet coating system. On the other hand, the ink used in the present invention is inexpensive and can use a photo radical polymerization initiator that does not generate strong acid or alkali, so that the ink can be manufactured at low cost and the ink jet coating system can be selected. Will also be easier. Of course, when using a high energy light source such as an electron beam, α, β, γ ray, X-ray, etc., it can be polymerized without using a polymerization initiator, but this is a generally known matter. There is no explanation here.

Examples of the photo radical polymerization initiator include a molecular cleavage type photo polymerization initiator and a hydrogen abstraction type photo polymerization initiator.
Examples of molecular cleavage type photopolymerization initiators include 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropane-1 -One, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1- {4- [4- (2-hydroxy -2-methylpropionyl) benzyl] phenyl} -2-methyl-1-propan-1-one, phenylglyoxyc acid methyl ester, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane -1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1,2-dimethylamino-2- (4- Tilbenzyl) -1- (4-morpholin-4-yl-phenyl) butan-1-one, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2, 4,4-trimethyl-pentylphosphine oxide, 2,4,6-trimethylbenzoylphosphine oxide, 1,2-octanedione- [4- (phenylthio) -2- (o-benzoyloxime)], ethanone-1 -[9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl] -1- (O-acetyloxime), [4- (methylphenylthio) phenyl] phenylmethanone, etc. .

Examples of hydrogen abstraction type photopolymerization initiators include benzophenone, methylbenzophenone, methyl-2-benzoylbenzoate, 4-benzoyl-4'-methyldiphenyl sulfide, benzophenone compounds such as phenylbenzophenone, 2,4-diethylthioxanthone Thioxanthone compounds such as 2-chlorothioxanthone, isopropylthioxanthone, and 1-chloro-4-propylthioxanthone.
An amine can be used in combination as a polymerization accelerator. Examples thereof include ethyl p-dimethylaminobenzoate, 2-ethylhexyl p-dimethylaminobenzoate, methyl p-dimethylaminobenzoate, 2-dimethylaminoethyl benzoate, butoxyethyl p-dimethylaminobenzoate, and the like. Is mentioned.

The polymer component contained in the photopolymerizable ink is added to improve the adhesion to the substrate to be printed. Thereby, sufficient adhesion can be secured even for a substrate such as a plastic material which is relatively smooth and difficult to secure adhesion of the coating film. In addition, since the polymer component has a high molecular weight, it is difficult to pass through the skin, and usually it does not have skin sensitivity.
The polymer component needs to have good solubility in the monomer component described above. For this reason, those having a crosslinked structure are unsuitable, and those having a chain structure are desirable. Moreover, even if it is chain-like, those having an excessively high molecular weight are not preferred because they significantly impair workability when dissolved in ink, and those having a mass average molecular weight of less than 100,000 are preferred. Furthermore, regarding solubility, it is also important that the polymer is not very rigid and the crystallinity is not too high. In addition, it is also important that it can be procured practically at low cost. In view of these points, the polymer species is preferably a polymer or copolymer consisting of at least one selected from styrene, styrene derivatives, acrylic acid esters, and acrylic acid, and chlorinated polyolefin. Vinyl monomers, polymers containing acrylamide and its derivatives, polyurethane, polyester, etc. can be used, but considering the fact that smaller molecular weight is preferable, it is assumed that operations such as three-dimensional stacking of printed coatings A polymer having a high glass transition temperature is desirable because it does not easily cause stickiness to the surface of the cured coating film of the ink. Therefore, the above-mentioned polymer or copolymer made of styrene or the like and chlorinated polyolefin are preferable. Since the monomers t-butyl methacrylate, n-pentyl methacrylate, and n-hexyl methacrylate described above are highly hydrophobic, it is better that the polymer component does not contain many polar groups in terms of solubility, and the acid value is 108 mgKOH. / G or less is desirable.

  Further, as required, 4-methoxy-1-naphthol, methylhydroquinone, hydroquinone, t-butylhydroquinone, di-t-butylhydroquinone, methoquinone, 2,2'-dihydroxy-3,3'-di (α- Methylcyclohexyl) -5,5'-dimethyldiphenylmethane, p-benzoquinone, di-t-butyldiphenylamine, 9,10-di-n-butoxycyantracene, 4,4 '-[1,10-dioxo-1,10 -Decandiylbis (oxy)] bis [2,2,6,6-tetramethyl] -1-piperidinyloxy and other polymerization inhibitors, higher fatty acid esters having polyether, amino group, carboxyl group and hydroxyl group, side Polydimethylsiloxaneization with polyether, amino group, carboxyl group or hydroxyl group at chain or terminal Things, polyethers, amino group, carboxyl group, a surfactant or the like fluoroalkyl compound having a hydroxyl group can be used such as a polar group-containing polymeric pigment dispersant.

<Ultraviolet light>
In the present invention, ultraviolet rays are used to cure the photopolymerizable ink. As for ultraviolet irradiation, mercury-free is strongly desired from the viewpoint of environmental protection, and replacement with a GaN-based semiconductor ultraviolet light-emitting device is very useful industrially and environmentally. Furthermore, an ultraviolet light emitting diode (UV-LED) and an ultraviolet laser diode (UV-LD) are small, have a long lifetime, high efficiency, and low cost, and are preferable as an ultraviolet light source.

<Color material>
The photopolymerizable ink used in the present invention may contain a color material. As the color material, various pigments and dyes that impart black, white, magenta, cyan, yellow, green, orange, glossy colors such as gold and silver, etc., depending on the purpose and required characteristics of the ink used in the present invention Can be used. The content of the color material may be appropriately determined in consideration of a desired color density, dispersibility in the ink, and the like, and is not particularly limited. However, the content of the color material is 0.1 to It is preferably 20% by mass. The photopolymerizable ink used in the present invention may be colorless and transparent without containing a color material. In that case, for example, it is suitable as an overcoat layer for protecting an image.
As the pigment, an inorganic pigment or an organic pigment can be used, and one kind may be used alone, or two or more kinds may be used in combination.
As the inorganic pigment, for example, carbon blacks (CI pigment black 7) such as furnace black, lamp black, acetylene black, channel black, iron oxide, and titanium oxide can be used.
Examples of the organic pigment include azo pigments such as insoluble azo pigments, condensed azo pigments, azo lakes and chelate azo pigments, phthalocyanine pigments, perylene and perinone pigments, anthraquinone pigments, quinacridone pigments, dioxane pigments, thioindigo pigments, isoindolinone pigments, and quinophthalone. Polycyclic pigments such as pigments, dye chelates (for example, basic dye type chelates, acidic dye type chelates), dyeing lakes (basic dye type lakes, acid dye type lakes), nitro pigments, nitroso pigments, aniline black, A daylight fluorescent pigment is mentioned.
Moreover, in order to make the dispersibility of a pigment more favorable, you may further contain a dispersing agent. Although it does not specifically limit as a dispersing agent, For example, the dispersing agent conventionally used for preparing pigment dispersions, such as a polymer dispersing agent, is mentioned.
As the dye, for example, an acid dye, a direct dye, a reactive dye, and a basic dye can be used. One kind may be used alone, or two or more kinds may be used in combination.

<Organic solvent>
The photopolymerizable ink used in the present invention may contain an organic solvent, but it is preferable not to contain it if possible. If the ink does not contain an organic solvent, particularly a volatile organic solvent (VOC (Volatile Organic Compounds) free), the safety of the place where the ink is handled is further improved, and environmental pollution can be prevented. The “organic solvent” means a general non-reactive organic solvent such as ether, ketone, xylene, ethyl acetate, cyclohexanone, and toluene, and should be distinguished from a reactive monomer. is there. Further, “not including” an organic solvent means that it does not substantially include, and is preferably less than 0.1% by mass.

<Other ingredients>
The photopolymerizable ink used in the present invention may contain other known components as necessary. Other components are not particularly limited. For example, conventionally known surfactants, polymerization inhibitors, leveling agents, antifoaming agents, fluorescent whitening agents, penetration accelerators, wetting agents (humectants), fixing Agents, viscosity stabilizers, antifungal agents, antiseptics, antioxidants, ultraviolet absorbers, chelating agents, pH adjusters, and thickeners.

<Preparation of photopolymerizable ink>
The photopolymerizable ink used in the present invention can be prepared using the above-described various components, and the preparation means and conditions thereof are not particularly limited. For example, a polymerizable monomer, a pigment, a dispersant, etc. , Put into a disperser such as a disk mill, pin mill, dyno mill, and so on to prepare a pigment dispersion, which is further mixed with a polymerizable monomer, an initiator, a polymerization inhibitor, a surfactant, and the like. Can be prepared.

<Viscosity>
The viscosity of the photopolymerizable ink used in the present invention may be appropriately adjusted depending on the application and application means, and is not particularly limited.For example, when applying an ejection means for ejecting the ink from a nozzle, The viscosity in the range of 20 ° C. to 65 ° C., desirably the viscosity at 25 ° C. is preferably 3 to 40 mPa · s, more preferably 5 to 15 mPa · s, and particularly preferably 6 to 12 mPa · s. Moreover, it is particularly preferable that the viscosity range is satisfied without including the organic solvent. In addition, the said viscosity uses a cone rotor (1 ° 34 ′ × R24) by a cone plate type rotational viscometer VISCOMETER TVE-22L manufactured by Toki Sangyo Co., Ltd., and has a rotation speed of 50 rpm and a constant temperature circulating water temperature of 20 ° C. It can be measured by appropriately setting in the range of ~ 65 ° C. VISCOMATE VM-150III can be used for temperature adjustment of circulating water.

<Application>
The use of the photopolymerizable ink used in the present invention is not particularly limited as long as it is a field in which photopolymerizable ink is generally used, and can be appropriately selected according to the purpose. For example, a molding resin, a paint, Examples thereof include adhesives, insulating materials, release agents, coating materials, sealing materials, various resists, and various optical materials.
Furthermore, the photopolymerizable ink used in the present invention not only forms two-dimensional characters and images, and design coatings on various substrates, but also three-dimensional for forming a three-dimensional solid image (three-dimensional model). It can also be used as a modeling material. This three-dimensional modeling material may be used, for example, as a binder between powder particles used in a powder lamination method in which three-dimensional modeling is performed by repeatedly curing and laminating a powder layer, as shown in FIGS. 2 and 3. You may use as a three-dimensional constituent material (model material) and support member (support material) which are used in such a layered modeling method (optical modeling method). FIG. 2 shows a method of performing three-dimensional modeling by sequentially laminating the photopolymerizable ink used in the present invention onto a predetermined region and sequentially irradiating and curing ultraviolet rays (details will be described later). Irradiates the storage pool (container) 1 of the photopolymerizable ink 5 used in the present invention with ultraviolet rays 4 to form a hardened layer 6 having a predetermined shape on the movable stage 3, and sequentially stacks these to form a three-dimensional model. How to do it.
As a three-dimensional modeling apparatus for modeling a three-dimensional modeled object using the photopolymerizable ink used in the present invention, a known one can be used, and is not particularly limited. And those equipped with a discharge means, an ultraviolet irradiation means and the like.
The present invention also includes a cured product obtained by curing a photopolymerizable ink and a molded product obtained by processing a structure in which the cured product is formed on a substrate. The molded product is obtained by subjecting a cured product or structure formed in a sheet shape or a film shape to a molding process such as heat stretching or punching, for example, an automobile, an OA device, an electric -It is suitably used for applications that require the surface to be molded after decorating, such as meters for electronic devices and cameras, and panels for operation units.
The substrate is not particularly limited and can be appropriately selected depending on the purpose. For example, paper, yarn, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, or a composite material thereof. From the viewpoint of processability, a plastic substrate is preferable.

<Ink container>
The ink storage container used in the present invention means a container in which a photopolymerizable ink is stored, and is suitable for use in the above applications. For example, a container containing ink can be used as an ink cartridge or an ink bottle, which eliminates the need for direct contact with ink in operations such as ink transport and ink replacement, and prevents dirt on fingers and clothes. be able to. In addition, foreign matters such as dust can be prevented from entering the ink. Further, the shape, size, material, and the like of the container itself may be suitable for use and usage, and are not particularly limited, but the material is a light-shielding material that does not transmit light, or the container is shielded from light. It is desirable to be covered with an adhesive sheet.

<Inkjet printing method, inkjet printing apparatus>
The inkjet printing method of the present invention includes an irradiation step of irradiating ultraviolet rays to cure at least the photopolymerizable ink used in the present invention. The inkjet printing apparatus of the present invention includes an ultraviolet irradiation means and light used in the present invention. A storage portion for storing the polymerizable ink, but the storage portion may store the above-described ink storage container. Furthermore, you may have the discharge process and discharge means which discharge photopolymerizable ink. The discharge method is not particularly limited, and examples thereof include a continuous injection type and an on-demand type. Examples of the on-demand type include a piezo method, a thermal method, and an electrostatic method.

FIG. 1 is a schematic view showing an example of the ink jet printing apparatus of the present invention.
The recording medium 22 supplied from the supply roll 21 by the ink jet discharge portions 23a, 23b, 23c, and 23d of each color of the printing unit 23 including the ink cartridges and discharge heads of the photopolymerizable inks of yellow, magenta, cyan, and black. Ink is discharged. Thereafter, the ink is cured by irradiating with ultraviolet rays from the light sources 24a, 24b, 24c, and 24d for curing the ink, thereby forming a color image. In addition, when the printing speed is increased, higher curability can be obtained by irradiating ultraviolet rays every time each color is printed. Thereafter, the recording medium 22 is conveyed to the processing unit 25 and the printed matter winding roll 26. A heating mechanism may be provided in each color inkjet discharge section 23a, 23b, 23c, 23d so that the ink is liquefied. Further, if necessary, a mechanism for cooling the recording medium to about room temperature by contact or non-contact may be provided. In addition, as an ink jet recording system, a serial system in which ink is ejected onto a recording medium by moving the head relative to a recording medium that moves intermittently according to the ejection head width, or the recording medium is moved continuously, Any of the line systems in which ink is ejected onto a recording medium from a head held at a fixed position can be applied.

The recording medium 22 is not particularly limited, and examples thereof include paper, film, metal, a composite material thereof, and the like, and may be in a sheet form. Moreover, the structure which enables only surface printing, or the structure which enables double-sided printing may be sufficient.
Further, the ultraviolet light from the light sources 24a, 24b, and 24c may be weakened or omitted, and after printing a plurality of colors, the ultraviolet light may be irradiated from the light source 24d. Thereby, energy saving and cost reduction can be achieved.
The recorded matter recorded by the present invention is not only printed on a smooth surface such as ordinary paper or resin film, but also printed on a surface to be printed having irregularities, and various types such as metal and ceramic. It includes those printed on the printing surface made of material. In addition, by stacking two-dimensional images, it is possible to form a three-dimensional image (a two-dimensional and three-dimensional image) or a three-dimensional object in part.

  FIG. 2 is a schematic diagram illustrating an example of a three-dimensional stereoscopic image forming apparatus according to the inkjet printing apparatus of the present invention. The ink jet printing apparatus 39 uses a head unit (movable in the AB direction) in which ink jet heads are arranged, and the first photopolymerizable ink from the shaped article discharge head unit 30 from the support discharge head units 31 and 32. A second photopolymerizable ink having a composition different from that of the first photopolymerizable ink is ejected and laminated while curing each ink by the adjacent ultraviolet irradiation means 33 and 34. More specifically, for example, the second photopolymerizable ink is discharged from the support discharge head units 31 and 32 on the model support substrate 37 and irradiated with ultraviolet rays to be solidified to have a reservoir. After forming the support layer, the step of discharging the first photopolymerizable ink from the modeling object discharge head unit 30 to the reservoir and irradiating it with ultraviolet rays to solidify and forming the first modeling layer. According to the number of times of stacking, the support layer and the modeled object layer are stacked by repeating a plurality of times while lowering the stage 38 that is movable in the vertical direction, thereby producing the three-dimensional modeled object 35. Thereafter, the support laminate 36 is removed as necessary. In FIG. 2, only one modeling object ejection head unit 30 is provided, but two or more modeling object ejection head units 30 may be provided.

The light source for curing is one in which each ultraviolet region such as UVA, UVB, and UVC is output as an emission spectrum, for example, a high-pressure mercury lamp, a metal halide lamp, an electrodeless UV lamp, a UV laser, a xenon lamp, an LED lamp, and a germicidal lamp. Etc. are used. In using these, in order to irradiate a fixed amount of light without using a reflector that actively blocks infrared rays, it has been found that the illuminance should be low and a smaller amount of UVA light. In addition, UVA here refers to the wavelength range of 320 to 390 nm, which is a relatively long wavelength among ultraviolet light.
The curing light source is equipped with a power change control function for the total output of the emission spectrum of each output region, in order to obtain the desired film characteristics necessary for ink curing from 0% output to 100% output. It is a system that can arbitrarily change the required irradiation intensity and integrated light quantity. This is a means for adjusting the irradiation intensity and the integrated light quantity.

  FIG. 3 is a schematic diagram illustrating another example of a three-dimensional stereoscopic image forming apparatus according to the inkjet printing apparatus of the present invention. In this apparatus, the storage pool (container) 1 of the photopolymerizable ink 5 is irradiated with ultraviolet rays 4 to form a hardened layer 6 having a predetermined shape on the movable stage 3, and this is sequentially laminated to perform three-dimensional modeling. That is, as shown in FIG. 3A, the photopolymerizable ink 5 in the storage pool (container) 1 is irradiated with ultraviolet rays 4 to form the cured layer 6 on the movable stage 3. Next, after the hardened layer 6 has a predetermined shape as shown in FIG. 3B, the movable stage 3 is lowered by a predetermined height as shown in FIG. Further, as shown in FIG. 3D, the photopolymerizable ink 5 in the storage pool (container) 1 is irradiated with ultraviolet rays 4 until the hardened layer 6 has a predetermined shape, and the hardened layer 6 is laminated. The three-dimensional modeling is performed by repeating the above.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated further more concretely, this invention is not limited by these Examples.

The following printing test was performed using the ink jet printing apparatus having the basic configuration shown in FIG. 1 and operating the ink jet discharge unit 23a and the curing light source 24a.
The following three types were used as UV light sources.
(I) Fusion system Japan UV irradiator LightHammer6 “D bulb” (with infrared cut reflector made by the company)
(II) Fusion Systems Japan UV irradiation machine “D bulb” (with reflector made by the company: does not actively cut infrared light)
(III) UV irradiation machine SubZero "D bulb" manufactured by Integration Technology (with reflector manufactured by the company: does not actively cut infrared light)

For the three types of light sources, the relationship between the irradiation conditions and the temperature rise (heating effect) was confirmed.
That is, using a stainless steel plate with a thickness of 0.5 mm, adjusting the illuminance and the conveyance speed so that the same integrated light amount is obtained, and the temperature rise width of the stainless steel plate when the belt conveyor is conveyed once under the light source ( ° C). The illuminance and the integrated light amount were measured using UV POWER PUCK II manufactured by EIT.
The results are shown in Table 1. It was found that even when the same UV integrated light amount was given, the temperature increase width was different when the type of light source, illuminance, and conveyance speed were different.

Examples 1-4, Comparative Examples 1-3
Curability evaluation was performed using the following evaluation inks A to C. The main monomer of each ink is a methacrylic acid ester, and the skin sensibility including all other components is negative. As described above, since the polymer component has a large molecular weight and it is difficult to pass through the skin, it usually does not have skin sensitivity.

(Evaluation ink A)
-N-pentyl methacrylate: 70 parts by weight Evaluation based on "n-AmylMethacrylate" (negative) literature manufactured by Zhangjiang Render Chemical (test method: maximization method)
Diethylene glycol dimethacrylate: 15 parts by weight “2G” (1.1) manufactured by Shin-Nakamura Chemical Co., Ltd.
・ Ethylene oxide-modified trimethylolpropane trimethacrylate 15 parts by weight “TMPT-3EO” (1.0) manufactured by Shin-Nakamura Chemical Co., Ltd.
Styrene acrylic resin: 14 parts by weight “JONCRYL611” manufactured by BASF (acid value 53 mgKOH / g weight average molecular weight 8100)
-Chlorinated polyolefin: 1 part by weight "Harlen DX-530P" manufactured by Toyobo Co., Ltd. (weight average molecular weight 40000)
2-dimethylamino-2- (4-methylbenzyl) -1- (4-morpholin-4-yl-phenyl) butan-1-one: 10 parts by weight “Irgacure 379” (none) manufactured by BASF Evaluation (Test method: OECD Test Guideline 406)

(Evaluation ink B)
-N-pentyl methacrylate: 70 parts by weight Evaluation based on "n-AmylMethacrylate" (negative) literature manufactured by Zhangjiang Render Chemical (test method: maximization method)
・ Glycerol dimethacrylate: 15 parts by weight “701” manufactured by Shin-Nakamura Chemical Co., Ltd.
・ Ethylene oxide-modified trimethylolpropane trimethacrylate 15 parts by weight “TMPT-3EO” (1.0) manufactured by Shin-Nakamura Chemical Co., Ltd.
Styrene acrylic resin: 14 parts by weight “JONCRYL611” manufactured by BASF (acid value 53 mgKOH / g weight average molecular weight 8100)
-Chlorinated polyolefin: 1 part by weight "Harlen DX-530P" manufactured by Toyobo Co., Ltd. (weight average molecular weight 40000)
2-dimethylamino-2- (4-methylbenzyl) -1- (4-morpholin-4-yl-phenyl) butan-1-one: 10 parts by weight “Irgacure 379” (none) manufactured by BASF Evaluation (Test method: OECD Test Guideline 406)

(Evaluation ink C)
-N-pentyl methacrylate: 84 parts by weight Evaluation based on "n-AmylMethacrylate" (negative) literature manufactured by Zhangjiang Render Chemical Co. (test method: maximization method)
Diethylene glycol dimethacrylate: 15 parts by weight “2G” (1.1) manufactured by Shin-Nakamura Chemical Co., Ltd.
・ Ethylene oxide-modified trimethylolpropane trimethacrylate 15 parts by weight “TMPT-3EO” (1.0) manufactured by Shin-Nakamura Chemical Co., Ltd.
-Chlorinated polyolefin: 1 part by weight "Harlen DX-530P" manufactured by Toyobo Co., Ltd. (weight average molecular weight 40000)
2-dimethylamino-2- (4-methylbenzyl) -1- (4-morpholin-4-yl-phenyl) butan-1-one: 10 parts by weight “Irgacure 379” (none) manufactured by BASF Evaluation (Test method: OECD Test Guideline 406)

As an operation, an aluminum pouch bag in which ink is sealed to prevent bubbles from entering is stored in a plastic cartridge, and the ink flow path from the cartridge to the GEN4 head manufactured by Ricoh Printing Systems Co., Ltd. And a solid coating film was prepared by ink jet discharge.
The ejection conditions were such that the head temperature and ejection voltage were adjusted so that the flying speed of ink droplets was 7 m / s, and the ejection density was adjusted so that the average thickness of the coating film was 8 microns.
All curing was performed by one UV irradiation, and evaluation was performed by finger touch. The state where the stickiness was not felt was regarded as tack-free, which is generally called, and it was judged that it was cured.
The results are shown in Table 2. As the UVA integrated light amount required for tack-free is smaller, the curability is better.
In addition, the polypropylene film "Toyobo Co., Ltd. polypropylene film P-2161 (60 micron thickness)" considered to be heat-sensitive among plastic substrates was used for the substrate.

From the results of Examples 1 to 4 in Table 2, it can be seen that when UV irradiation conditions having a larger temperature increase range (higher heating effect) are adopted, curing can be performed with a smaller amount of UVA light.
In addition, since Comparative Example 1 is Condition 1 in which the temperature increase range is the smallest of Conditions 1 to 4 (the heating effect is low), the integrated light quantity required for tack-free is 3 J, and the efficiency is very low. It was.
Moreover, in the comparative example 2 which repeated condition 4 twice continuously, the base material and the coating film deform | transformed with the heat | fever, and it melted partially. In this way, if the heating effect is excessive, the base material and the coating film will be damaged by heat, so appropriate conditions are selected according to the base material used, especially for fabrics that are sensitive to heat. There is a need to.
In addition, as in Comparative Example 3, it is understood that even when the ink containing no polymer component is used, even under Condition 4, the base material and the coating film are deformed by heat and partially melt.

1 Reservation pool (container)
DESCRIPTION OF SYMBOLS 3 Movable stage 4 Ultraviolet ray 5 Photopolymerizable ink 6 Hardening layer 21 Supply roll 22 Recording medium 23 Printing unit 23a Inkjet ejection part 23b Inkjet ejection part 23c Inkjet ejection part 23d Inkjet ejection part 24a Curing light source 24b Curing light source 24c Curing light source 24d Curing light source 25 Processing unit 26 Printed material winding roll 30 Modeling object ejection head unit 31 Supporting body ejection head unit 32 Supporting body ejection head unit 33 Ultraviolet irradiation means 34 Ultraviolet irradiation means 35 Three-dimensional modeling object 36 Support laminate 37 Modeling object support substrate 38 Stage movable up and down 39 Inkjet printing apparatus A Movable direction B Movable direction

Japanese Patent No. 4733909 Japanese Patent Publication No. 07-10894 JP 2013-249357 A

Claims (5)

An apparatus for printing using a photopolymerizable ink containing at least n-pentyl methacrylate and a polymer component, comprising at least ultraviolet irradiation means, and one irradiation with UV light in the UVA region (wavelength: 320 nm to 390 nm) In the inkjet printing apparatus, the temperature of the stainless steel plate having a thickness of 0.5 mm can be increased from 23 ° C. to 36 ° C. or more when the integrated light quantity is 1.8 J / cm ² .   The inkjet printing apparatus according to claim 1, wherein the temperature of the stainless steel plate can be increased from 23 ° C. to 43 ° C. or more.   The inkjet printing apparatus according to claim 1, wherein the temperature of the stainless steel plate can be increased from 23 ° C. to 54 ° C. or more.   The photopolymerizable ink is 1-hydroxycyclohexyl phenyl ketone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1, 2-dimethylamino-2- (4-methylbenzyl) -1. 2. It contains at least one selected from-(4-morpholin-4-yl-phenyl) butan-1-one and bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide. The inkjet printing apparatus in any one of -3. A photopolymerizable ink containing at least n-pentyl methacrylate and a polymer component is applied on a base material, and the ink is applied once by UV light in a UVA region (wavelength: 320 nm to 390 nm) using an ultraviolet irradiation device. In the light irradiation, when the integrated light quantity is 1.8 J / cm ² , it was produced by light irradiation under irradiation conditions that can raise the temperature of a stainless steel plate having a thickness of 0.5 mm from 23 ° C. to 36 ° C. or more. Cured product.

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