JP6903283B2 - Active energy ray-curable composition, cured product, composition container, image forming apparatus, and image forming method - Google Patents

Description

The present invention relates to an active energy ray-curable composition, a cured product, a composition container, an image forming apparatus, and an image forming method.

Radical-polymerizable inks and cationically polymerizable inks are used in the active energy ray-curable inkjet recording method. Among these, radical-polymerizable inks are widely used from the viewpoint of ink production cost and storage stability. Has been done.
Since the active energy ray-curable radical polymerizable ink can have a low viscosity and can be cured with a small amount of energy, it is active with a polymerizable monomer represented by an acrylic acid ester as a main component. A composition containing a polymerization initiator that generates radicals when irradiated with energy rays is known.

However, many of the acrylic acid esters and the polymerization initiators have sensitizing properties to the skin, and if an ink containing them is mistakenly attached to the skin, there is a problem that an allergic reaction may occur. There is.

Therefore, an ink jet ink containing no acrylic acid ester has been proposed (see, for example, Patent Document 1).
Further, ink jet inks using a compound having a negative skin sensitization property have been proposed (see, for example, Patent Documents 2 to 4).

An object of the present invention is to provide an active energy ray-curable composition which does not have a problem of skin sensitization and can be cured with a small amount of energy.

The active energy ray-curable composition of the present invention as a means for solving the above-mentioned problems is
An active energy ray-curable composition containing a polymerizable monomer (A) and a polymerization initiator (B), in which 99.0% by mass or more of the active energy ray-curable composition has skin sensitization. The polymerization initiator (B) is composed of components that do not, and the polymerization initiator (B1) having skin sensitivities is contained in the active energy ray-curable composition in an amount of 0.1% by mass or more and less than 1.0% by mass. It is an active energy ray-curable composition, which is characterized by containing.

According to the present invention, it is possible to provide an active energy ray-curable composition which does not have a problem of skin sensitization and can be cured with a small amount of energy.

It is the schematic which shows an example of the image forming apparatus in this invention. It is the schematic which shows an example of another image forming apparatus in this invention. It is the schematic which shows an example of still another image forming apparatus in this invention.

The present invention relates to the active energy ray-curable composition described in (1) below, but the following (2) to (9) are also included as embodiments of the present invention. explain.
(1) An active energy ray-curable composition containing a polymerizable monomer (A) and a polymerization initiator (B).
99.0% by mass or more of the active energy ray-curable composition is composed of a component having no skin sensitization.
The polymerization initiator (B) is characterized by containing a skin-sensitizing polymerization initiator (B1) in the active energy ray-curable composition in an amount of 0.1% by mass or more and less than 1.0% by mass. Active energy ray-curable composition.
(2) The polymerization initiator (B) further contains a polymerization initiator (B2) having no skin sensitivities in the active energy ray-curable composition in an amount of 1.0% by mass or more and 20.0% by mass or less. The active energy ray-curable composition according to (1) above.
(3) The above-mentioned (1) or (2), wherein the polymerization initiator (B1) having skin sensitization is at least one selected from the group consisting of an acylphosphine oxide compound and an oxime ester compound. Active energy ray-curable composition.
(4) The above-mentioned (2) or (3), wherein the polymerization initiator (B2) having no skin sensitization is at least one selected from the group consisting of α-aminoketone compounds and α-hydroxyketone compounds. The active energy ray-curable composition according to.
(5) The active energy ray-curable composition according to any one of (1) to (4) above, wherein the polymerizable monomer (A) contains a monofunctional acrylamide compound having no skin sensitization property.
(6) A cured product of the active energy ray-curable composition according to any one of (1) to (5) above.
(7) A composition container containing the active energy ray-curable composition according to any one of (1) to (5) above.
(8) The composition storage container according to (7) above, the means for discharging the active energy ray-curable composition contained in the composition storage container, and the discharged active energy ray-curable composition. A two-dimensional or three-dimensional image forming apparatus including means for irradiating active energy rays.
(9) A step of discharging the active energy ray-curable composition according to any one of (1) to (5) above, and a step of irradiating the discharged active energy ray-curable composition with active energy rays. A two-dimensional or three-dimensional image forming method including.

The active energy ray-curable composition of the present invention contains a polymerizable monomer (A) and a polymerization initiator (B), and 99.0% by mass or more of the active energy ray-curable composition is skin sensitizing. In the active energy ray-curable composition, 0.1% by mass or more and 1.0% by mass of the polymerization initiator (B1) having the polymerization initiator (B) having skin sensitivities, which is composed of a component having no It is an active energy ray-curable composition characterized by containing less than.

In the present invention, the fact that a compound has skin sensitization means that the compound is determined to be positive in a skin sensitization test. The method of the skin sensitization test is not particularly limited, and a known method can be appropriately selected and applied. For example, the degree of sensitization is determined by evaluation by the LLNA (Local Lymph Node Assay) method. When the indicated SI (Stimulation Index) is 3 or more, it is determined to be positive.
In addition, the fact that the compound does not have skin sensitization means that the compound is judged to be negative in the skin sensitization test.

All compounds can be classified as having or not having skin sensitization by such a skin sensitization test. Compounds whose skin sensitization is unknown due to the absence of data are also essentially classified as those having or not having skin sensitization.
The active energy ray-curable composition of the present invention is composed of 99.0% by mass or more of components having no skin sensitization, but if it is clear that this is satisfied, a trace amount of components The skin sensitization property may remain unknown.

Information on the skin sensitization of commercially available compounds can be obtained from the "Safety Data Sheet" (hereinafter referred to as SDS) provided with the compounds. The SDS is preferably compliant with the "Globally Harmonized System for Classification and Labeling of Chemicals" (hereinafter referred to as GHS), and in such SDS, if the compound has skin sensitization, it is considered to be skin sensitizing as a hazard. Information on "Category 1" is notified, or in more detail, skin sensitizer "Subcategory 1A" (strong skin sensitizer) or "Subcategory 1B" (other skin sensitizers). Information will be notified. Even if the SDS is not GHS compliant, information such as positive / negative in the skin sensitization test or skin sensitization / non-skin sensitization based on the skin sensitization test results may be provided.
Information on the skin sensitization of compounds can also be obtained from the literature [eg, Contact Dermatitis 8 223-235 (1982)].

The polymerization initiator (B) contains a polymerization initiator (B1) having skin sensitization properties. As will be described later, some polymerization initiators are known to have no skin sensitization property, but a polymerization initiator having skin sensitization property generally has a high ability to initiate polymerization and is advantageous in improving curability. Is.
The polymerization initiator (B1) having skin sensitization is contained in the active energy ray-curable composition in an amount of 0.1% by mass or more and less than 1.0% by mass, but for functioning as a polymerization initiator. A content of 0.1% by mass or more is required as a practical lower limit, while the content is less than 1.0% by mass from the viewpoint of reducing the risk of skin sensitization as an active energy ray-curable composition. It is necessary to suppress the upper limit of.

It is preferable that the polymerization initiator (B1) having skin sensitization is not a compound having a skin sensitization subcategory 1A because of its hazard in GHS. That is, the polymerization initiator (B1) having skin sensitization is preferably a compound of skin sensitization category 1 or skin sensitization subsection 1B, and further, skin sensitization subcategory 1B. More preferably, it is a compound.

The polymerization initiator (B1) having skin sensitization property is preferably selected from acylphosphine oxide-based or oxime ester-based compounds. Specific examples include, but are not limited to, the following compounds.

[Polymerization initiator (B1)]
<Acylphosphine oxide system>
Diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide [BASF Japan Ltd. "Irgacure TPO", skin sensitization subdivision 1B (SDS information)]
Phenylbis (2,4,6-trimethylbenzoyl) phosphine oxide [BASF Japan Ltd. "Irgacure 819", skin sensitization category 1 (SDS information)]

<Oxime ester type>
1- [4- (Phenylthio) phenyl] octane-1,2-dione = 2- (O-benzoyloxime) [BASF Japan Ltd. "Irgacure OXE01", skin sensitization category 1 (SDS information)]
1- [9-Ethyl-6- (2-Methylbenzoyl) -9H-Carbazole-3-yl] Etanone = O-Acetyl Oxime [BASF Japan Ltd. "Irgacure OXE02", Skin Sensitization Subdivision 1B (SDS) information)〕
These may be used alone or in combination of two or more.

The polymerization initiator (B) can further contain a polymerization initiator (B2) having no skin sensitization in an active energy ray-curable composition in an amount of 1.0% by mass or more and 20.0% by mass or less. .. The polymerization initiator (B2) having no skin sensitization is generally not so high in ability to initiate polymerization, but can be used for the purpose of supplementing the polymerization initiator (B1) having skin sensitization. ..

The polymerization initiator (B2) having no skin sensitization property is preferably selected from α-aminoketone-based or α-hydroxyketone-based compounds. Specific examples include, but are not limited to, the following compounds.

[Polymerization initiator (B2)]
<Α-Aminoketone system>
2-Methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1-one [BASF Japan Ltd. "Irgacure 907", skin sensitization test negative (SDS information)]
2- (Dimethylamino) -2-[(4-methylphenyl) methyl] -1- (4-morpholinophenyl) butane-1-one [BASF Japan Ltd. "Irgacure 379", skin sensitization test negative ( SDS information)]

<Α-Hydroxyketone system>
1-Hydroxycyclohexyl = phenyl = ketone [BASF Japan Ltd. "Irgacure 184", negative skin sensitization test (SDS information)]
1- [4- (2-Hydroxyethoxy) phenyl] -2-hydroxy-2-methylpropan-1-one [BASF Japan Ltd. "Irgacure 2959", skin sensitization test negative (SDS information)]
These may be used alone or in combination of two or more.

[Polymerizable Monomer (A)]
As the polymerizable monomer (A), a compound having at least one polymerizable reactive group and having no skin sensitization property is used.
Examples of the polymerizable reactive group include, but are not limited to, groups having a polymerizable unsaturated bond such as an acryloyl group, a methacryloyl group, an acrylamide group, a methacrylicamide group, a vinyl group, a vinyloxy group, and an allyl group. Specific examples of the compound that can be used as the polymerizable monomer (A) are exemplified in Patent Documents 1 to 4, and the viscosity and curability of the target active energy ray-curable composition and the obtained cured films are various. It can be appropriately selected and used according to its physical properties (hardness, adhesion, optical properties, etc.). The number of polymerizable reactive groups (number of functional groups) of the polymerizable monomer (A) and the molecular weight of the polymerizable monomer (A) are not particularly limited, and the polymerizable monomer (A) may be an oligomer or the like. It also includes compounds such as macromonomers.

In the present invention, the polymerizable monomer (A) preferably contains a monofunctional acrylamide compound having no skin sensitization property.
Specific examples of the monofunctional acrylamide compound having no skin sensitization include the following compounds.
Acryloyl morpholine ["ACMO" manufactured by KJ Chemicals Co., Ltd., negative skin sensitization test (SDS information)]
N- (2-Hydroxyethyl) acrylamide ["HEAA" manufactured by KJ Chemicals Co., Ltd., negative skin sensitization test (SDS information)]
The monofunctional acrylamide compound is useful because it gives a cured product having excellent curability and excellent hardness and adhesion.

Further, as the polymerizable monomer (A), a polyfunctional (meth) acrylic acid ester having no skin sensitization is also preferable, for example, tricyclodecanedimethanol dimethacrylate (bifunctional), neopentyl glycol dimethacrylate. Examples thereof include (bifunctional) and caprolactone-modified dipentaerythritol hexaacrylate (bifunctional).

In addition, the active energy ray-curable composition of the present invention may contain other components described later, if necessary.

<Active energy ray>
The active energy rays used for curing the active energy ray-curable composition of the present invention include polymerizable components in the composition such as electron beams, α rays, β rays, γ rays, and X rays in addition to ultraviolet rays. It is not particularly limited as long as it can impart the energy required for advancing the polymerization reaction of. In particular, when a high-energy light source is used, the polymerization reaction can proceed without using a polymerization initiator. Further, in the case of 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. Further, the ultraviolet light emitting diode (UV-LED) and the ultraviolet laser diode (UV-LD) are compact, have a long life, have high efficiency, and are low in cost, and are preferable as an ultraviolet light source.

<Color material>
The active energy ray-curable composition of the present invention may contain a coloring material. As the coloring 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 composition in the present invention. Can be used. The content of the coloring material may be appropriately determined in consideration of the desired color concentration, dispersibility in the composition, etc., and is not particularly limited, but is 0. It is preferably 1 to 20% by mass.
The active energy ray-curable composition of the present invention may be colorless and transparent without containing a coloring material, and 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 type may be used alone or two or more types may be used in combination.
As the inorganic pigment, for example, carbon black (CI pigment black 7) such as furnace black, lamp black, acetylene black, and channel black, iron oxide, and titanium oxide can be used.
Examples of organic pigments include azo pigments such as insoluble azo pigments, condensed azo pigments, azolakes and chelate azo pigments, phthalocyanine pigments, perylene and perinone pigments, anthraquinone pigments, quinacridone pigments, dioxane pigments, thioindigo pigments, isoindolinone pigments and quinophthalones. Polycyclic pigments such as pigments, dye chelate (for example, basic dye type chelate, acidic dye type chelate, etc.), dyeing lake (basic dye type lake, acidic dye type lake), nitro pigment, nitroso pigment, aniline black, Daylight fluorescent pigments can be mentioned.
In addition, a dispersant may be further contained in order to improve the dispersibility of the pigment. The dispersant is not particularly limited, and examples thereof include dispersants commonly used for preparing pigment dispersions such as polymer dispersants.
As the dye, for example, an acid dye, a direct dye, a reactive dye, and a basic dye can be used, and one type may be used alone or two or more types may be used in combination.

<Organic solvent>
The active energy ray-curable composition of the present invention may contain an organic solvent, but it is preferable not to contain it if possible. If the composition does not contain an organic solvent, particularly a volatile organic solvent (VOC (Volatile Organic Compounds) free), the safety of the place where the composition is handled is further enhanced, and it is possible to prevent environmental pollution. .. The "organic solvent" means, for example, a general non-reactive organic solvent such as ether, ketone, xylene, ethyl acetate, cyclohexanone, and toluene, and should be distinguished from the reactive monomer. is there. Further, "not containing" the organic solvent means that it is substantially not contained, and it is preferably less than 0.1% by mass.

<Other ingredients>
The active energy ray-curable composition of the present invention may contain other known components, if necessary. The other components are not particularly limited, but are, for example, conventionally known surfactants, polymerization inhibitors, leveling agents, antifoaming agents, fluorescent whitening agents, penetration promoters, wetting agents (moisturizers), and fixing agents. Agents, viscosity stabilizers, fungicides, preservatives, antioxidants, UV absorbers, chelating agents, pH regulators, thickeners and the like.

<Adjustment of active energy ray-curable composition>
The active energy ray-curable composition of the present invention can be prepared by using the above-mentioned various components, and the adjusting means and conditions thereof are not particularly limited. For example, a polymerizable monomer, a pigment, a dispersant and the like are used in a ball mill. It is put into a disperser such as a kitty mill, a disc mill, a pin mill, or a dyno mill, and dispersed to prepare a pigment dispersion liquid, and a polymerizable monomer, an initiator, a polymerization inhibitor, a surfactant, etc. are further mixed with the pigment dispersion liquid. It can be adjusted by making it.

<Viscosity>
The viscosity of the active energy ray-curable composition of the present invention may be appropriately adjusted according to the application and application means, and is not particularly limited. For example, when a discharge means for discharging the composition from a nozzle is applied. The viscosity in the range of 20 ° C. to 65 ° C., preferably 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. Further, it is particularly preferable that the viscosity range is satisfied without containing the organic solvent. For the above viscosity, a cone rotor (1 ° 34'x R24) was used with a cone plate type rotational viscometer VISCOMETER TVE-22L manufactured by Toki Sangyo Co., Ltd., the rotation speed was 50 rpm, and the temperature of constant temperature circulating water was 20 ° C. It can be appropriately set and measured in the range of ~ 65 ° C. VISCOMATE VM-150III can be used to adjust the temperature of the circulating water.

<Use>
The application of the active energy ray-curable composition of the present invention is not particularly limited as long as it is in a field in which an active energy ray-curable material is generally used, and can be appropriately selected depending on the intended purpose, for example, for molding. Examples thereof include resins, paints, adhesives, insulating materials, mold release agents, coating materials, sealing materials, various resists, and various optical materials.
Further, the active energy ray-curable composition of the present invention can be used as an ink to not only form two-dimensional characters and images and design coatings on various substrates, but also to form a three-dimensional three-dimensional image (three-dimensional model). It can also be used as a three-dimensional modeling material for forming. 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, and is also shown in FIGS. 2 and 3. It may be used as a three-dimensional constituent material (model material) or a support member (support material) used in such a laminated modeling method (stereolithography). Note that FIG. 2 is a method in which the active energy ray-curable composition of the present invention is discharged into a predetermined region, and those cured by irradiating with active energy rays are sequentially laminated to perform three-dimensional modeling (details will be described later). FIG. 3 shows that the storage pool (accommodation portion) 1 of the active energy ray-curable composition 5 of the present invention is irradiated with the active energy ray 4 to form a cured layer 6 having a predetermined shape on the movable stage 3. This is a method of sequentially laminating and performing three-dimensional modeling.
As a three-dimensional modeling device for modeling a three-dimensional model using the active energy ray-curable composition of the present invention, a known one can be used, and the present invention is not particularly limited, but for example, a means for accommodating the composition. , A supply means, a discharge means, an active energy ray irradiation means, and the like.
The present invention also includes a cured product obtained by curing an active energy ray-curable composition and a molded product obtained by processing a structure in which the cured product is formed on a substrate. The molded product is, for example, a cured product or structure formed in a sheet shape or a film shape that has been subjected to molding processing such as heat stretching or punching, and is, for example, an automobile, an OA device, or electricity. -Suitably used for applications that require molding after decorating the surface, such as electronic devices, meters for cameras, panels for operation units, and the like.
The base material is not particularly limited and may be appropriately selected depending on the intended purpose. For example, paper, thread, fiber, cloth, leather, metal, plastic, glass, wood, ceramics, or a composite material thereof and the like. From the viewpoint of processability, a plastic base material is preferable.

<Composition container>
The composition container of the present invention means a container in which an active energy ray-curable composition is contained, and is suitable for use in the above-mentioned applications. For example, when the active energy ray-curable composition of the present invention is used for ink, the container containing the ink can be used as an ink cartridge or an ink bottle, whereby ink transfer, ink replacement, etc. It is not necessary to directly touch the ink in the work, and it is possible to prevent the fingers and clothes from getting dirty. In addition, it is possible to prevent foreign substances such as dust from being mixed into the ink. The shape, size, material, etc. of the container itself may be suitable for the intended use and usage, and is not particularly limited, but the material is a light-shielding material that does not transmit light, or the container blocks light. It is desirable that it is covered with a sex sheet or the like.

<Image formation method, forming device>
The method for forming an image of the present invention includes, at least, an irradiation step of irradiating an active energy ray to cure the active energy ray-curable composition of the present invention, and the image forming apparatus of the present invention has an active energy. An irradiation means for irradiating the rays and an accommodating portion for accommodating the active energy ray-curable composition of the present invention may be provided, and the container may be accommodated in the accommodating portion. Further, it may have a discharge step and a discharge means for discharging the active energy ray-curable composition. The method of discharging 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 an example of an image forming apparatus provided with an inkjet ejection means. Ink is ejected to the recording medium 22 supplied from the supply roll 21 by each color printing unit 23a, 23b, 23c, 23d provided with an ink cartridge for each color active energy ray-curable ink of yellow, magenta, cyan, and black and an ejection head. Will be done. Then, the light sources 24a, 24b, 24c, and 24d for curing the ink are irradiated with active energy rays to cure the ink, and a color image is formed. After that, the recording medium 22 is conveyed to the processing unit 25 and the printed matter take-up roll 26. Each printing unit 23a, 23b, 23c, 23d may be provided with a heating mechanism so that the ink is liquefied at the ink ejection portion. Further, if necessary, a mechanism for cooling the recording medium to about room temperature by contact or non-contact may be provided. Further, as an inkjet recording method, a serial method in which the head is moved to eject ink onto the recording medium or a recording medium is continuously moved with respect to a recording medium that moves intermittently according to the width of the ejection head. Any of the line methods of ejecting ink onto the recording medium from the head held at a fixed position can be applied.
The recording medium 22 is not particularly limited, and examples thereof include paper, film, metal, and composite materials thereof, and may be in the form of a sheet. Further, the configuration may be such that only single-sided printing is possible, or double-sided printing is also possible.
Further, the activation energy rays from the light sources 24a, 24b, and 24c may be weakened or omitted, and after printing a plurality of colors, the activation energy rays may be irradiated from the light source 24d. As a result, energy saving and cost reduction can be achieved.
The recorded matter recorded by the ink of the present invention includes not only those printed on a smooth surface such as ordinary paper or resin film, but also those printed on an uneven surface to be printed, metal, ceramic, and the like. It also includes those printed on the surface to be printed made of various materials. Further, by superimposing two-dimensional images, it is possible to form a partially three-dimensional image (an image composed of two-dimensional and three-dimensional) or a three-dimensional object.
FIG. 2 is a schematic view showing an example of another image forming apparatus (three-dimensional stereoscopic image forming apparatus) according to the present invention. The image forming apparatus 39 of FIG. 2 uses a head unit (movable in the AB direction) in which inkjet heads are arranged to discharge the first active energy ray-curable composition from the discharge head unit 30 for a modeled object for a support. The second active energy ray-curable composition having a composition different from that of the first active energy ray-curable composition is discharged from the head units 31 and 32, and each of these compositions is cured by the adjacent ultraviolet irradiation means 33 and 34. While stacking. More specifically, for example, the second active energy ray-curable composition is discharged from the support discharge head units 31 and 32 onto the modeled object support substrate 37, and is irradiated with active energy rays to be solidified. After forming the first support layer having the reservoir portion, the first active energy ray-curable composition is discharged from the discharge head unit 30 for a modeled object to the reservoir portion, and is solidified by irradiating the reservoir portion with the active energy ray. By repeating the process of forming the first modeled object layer a plurality of times while lowering the vertically movable stage 38 according to the number of times of stacking, the support layer and the modeled object layer are laminated to form the three-dimensional modeled object 35. To make. After that, the support laminated portion 36 is removed as needed. In FIG. 2, only one discharge head unit 30 for a modeled object is provided, but two or more may be provided.

Hereinafter, examples of the present invention will be described, but the present invention is not limited to these examples.
First, the names of various reagents and manufacturers used in Examples and Comparative Examples are shown in Table 1 below.
Here, for skin sensitization, the information is described for those for which information can be obtained from SDS (refer to the English SDS issued outside Japan as necessary). Further, for those in which the SI by the LLNA method is described, the values measured by the method described in Patent Document 1 are shown.

(Example 1)
<Preparation of active energy ray-curable composition 1>
Acryloylmorpholine (“ACMO” manufactured by KJ Chemicals Co., Ltd.) 99.1% by mass and diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide (“Irgacure TPO” manufactured by BASF Japan Ltd.) 0.9% by mass After adding them in order and stirring for 1 hour and visually confirming that there was no undissolved residue, the coarse particles were removed by filtration through a membrane filter to prepare an active energy ray-curable composition 1.

(Examples 2 to 8 and Comparative Examples 1 to 3)
<Preparation of active energy ray-curable compositions 2-11>
In Example 1, active energy ray-curable compositions 2 to 11 were prepared in the same manner as in Example 1 except that the composition and content were changed to those shown in Table 2 below.

<Evaluation of curability of active energy ray-curable compositions 1 to 11>
As an evaluation of the curability of the active energy ray-curable compositions 1 to 11, the amount of light irradiation required for curing the active energy ray-curable composition was measured by a viscoelasticity measuring device (“MCR302” manufactured by Anton Paar Japan K.K. ) Was measured by the following method, and the results are shown in Table 2.
(Measuring method)
A flat measuring jig having a diameter of 20 mm was placed on a glass stage with a gap of 10 μm, and an active energy ray-curable composition was sandwiched between the gaps to form a liquid film having a thickness of 10 μm. From the underside of the glass stage, an LED light source (“LIGHTNINGCURE LC-L1” manufactured by Hamamatsu Photonics Co., Ltd., wavelength 365 nm, illuminance 10 mW / cm ^{2 measured by an ultraviolet luminometer (“UIT-201” manufactured by Ushio Electric Co., Ltd.) on the glass stage)} ), The change in the storage elastic modulus of the active energy ray-curable composition is observed in the vibration mode, and the time from the start of the light irradiation until the increase in the storage elastic modulus is saturated and reaches a constant value. (Seconds) was measured as the curing time. ^{The amount of light irradiation (mJ / cm 2} ) required for curing the active energy ray-curable composition was calculated as the product of the illuminance and the curing time.

After the measurement, the liquid film of the active energy ray-curable composition became a transparent cured film, and the glass stage and the measuring jig were strongly adhered to each other via the cured film.
The values of the reached storage elastic modulus (Pa) are also shown in Table 1. Incidentally, the storage elastic modulus in the state before the light irradiation of the liquid film was ¹⁰ 0 ^~10 1 Pa.

From Table 2, the light irradiation amounts required for curing the active energy ray-curable compositions of Examples 1 to 4 and Comparative Example 1 and Examples 5 to 8 and Comparative Example 2 having the same amount of the polymerization initiator are shown. By comparison, it can be seen that the amount of light irradiation in the examples is small in each case and the curability is excellent. Further, in Examples 5, 6 and 8, the amount of the polymerization initiator compounded is 1/9 of that of Comparative Example 1, but the curability is superior to that of Comparative Example 1. Further, the reached storage elastic modulus was higher in Examples 1 to 8 than in Comparative Examples 1 and 2, suggesting that a cured product having excellent hardness was produced in Examples.

(Examples 9 to 13)
In Examples 1 to 8, the curability of the ink was evaluated by measuring the viscoelasticity.
In Examples 9 to 13, ink was applied to the base material by inkjet, and the ink was cured by ultraviolet irradiation to form a printed image, and the image quality and adhesion of the printed image were evaluated.
<Preparation of active energy ray-curable compositions 12 to 16>
In Example 1, active energy ray-curable compositions 12 to 16 were prepared in the same manner as in Example 1 except that the composition and content were changed to those shown in Table 3 below.

<Formation of images of active energy ray-curable compositions 12 to 16 by inkjet>
Each of the active energy ray-curable compositions 12 to 16 is filled in a plastic composition container, and an inkjet head as a discharge means (“MH5440” manufactured by Ricoh Co., Ltd.) and an ultraviolet irradiation machine as an active energy ray irradiation means (“MH5440”). It was incorporated into an image forming apparatus equipped with a "LH6" manufactured by Fusion Systems Japan Co., Ltd.), a controller for controlling discharge, and a supply path from a composition container to an inkjet head. The active energy ray-curable composition is discharged from the inkjet head onto a polycarbonate base material (“Panlight Sheet PC-1151” manufactured by Teijin Limited) with a thickness of 40 μm, and is irradiated with light of 500 mJ / cm ^{2 with} an ultraviolet irradiator. To produce a printed image.
Table 3 shows the observation results of the printed image.
In all of the active energy ray-curable compositions 11 to 15, a good printed image (a uniform printed image having a transparent gloss without defects due to ejection defects or curing defects) was formed by inkjet.
In addition, the adhesion of the printed image was tested by the cross-cut method standardized in Japanese Industrial Standards (JIS) K5600-5-6. In all of the active energy ray-curable compositions 11 to 15, good adhesion (the edges of the cuts were completely smooth and there was no peeling in the eyes of any lattice) was confirmed.

1 Storage pool (accommodation)
3 Movable stage 4 Active energy ray 5 Active energy ray Curable composition 6 Cured layer 21 Supply roll 22 Recording medium 23a, 23b, 23c, 23d Printing unit 24a, 24b, 24c, 24d Light source 25 Processing unit 26 Printed matter winding roll 30 Discharge head unit for modeled object 31, 32 Discharge head unit for support 33, 34 Ultraviolet irradiation means 35 Three-dimensional modeled object 36 Support laminated part 37 Modeled object support substrate 38 Stage 39 Image forming device

Japanese Unexamined Patent Publication No. 2012-140593 Japanese Unexamined Patent Publication No. 2012-251123 Japanese Unexamined Patent Publication No. 2013-7021 Japanese Unexamined Patent Publication No. 2013-95910

Claims (6)

An active energy ray-curable composition containing a polymerizable monomer (A) and a polymerization initiator (B).
99.0% by mass or more of the active energy ray-curable composition is composed of a component having no skin sensitization.
The polymerization initiator (B) contains a polymerization initiator (B1) having skin sensitization in the active energy ray-curable composition in an amount of 0.1% by mass or more and less than 1.0% by mass.
The polymerizable monomer (A) is at least one selected from the following A-1, A-3, A-4, and A-5.
An active energy ray-curable composition, wherein the polymerization initiator (B1) is at least one selected from the following B1-2, B1-3, and B1-4.
[Polymerizable monomer]
A-1: Acryloyl morpholine A-3: Caprolactone-modified dipentaerythritol hexaacrylate A-4: Tricyclodecanedimethanol dimethacrylate A-5: Neopentyl glycol dimethacrylate [polymerization initiator (B1)]
B1-2: Phenylbis (2,4,6-trimethylbenzoyl) phosphine oxide B1-3: 1- [4- (phenylthio) phenyl] octane-1,2-dione = 2- (O-benzoyloxime)
B1-4: 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazole-3-yl] ethanone = O-acetyloxime The polymerization initiator (B) further contains a polymerization initiator (B2) having no skin sensitization in an active energy ray-curable composition in an amount of 1.0% by mass or more and 20.0% by mass or less.
The active energy ray-curable composition according to claim 1, wherein the polymerization initiator (B2) is at least one selected from the following B2-1 to B2-4.
[Polymerization initiator (B2)]
B2-1: 2-Methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1-one B2-2: 2- (dimethylamino) -2-[(4-methylphenyl) methyl] 1 -(4-Molholinophenyl) butane-1-one B2-3: 1-hydroxycyclohexyl = phenyl = ketone B2-4: 1- [4- (2-hydroxyethoxy) phenyl] -2-hydroxy-2-methylpropane -1-On A cured product of the active energy ray-curable composition according to claim 1 or 2. A composition container containing the active energy ray-curable composition according to claim 1 or 2. The composition accommodating container according to claim 4, the means for discharging the active energy ray-curable composition contained in the composition accommodating container, and the activated energy ray-curable composition discharged. A two-dimensional or three-dimensional image forming apparatus including means for irradiating. A two-dimensional or three-dimensional step including a step of discharging the active energy ray-curable composition according to claim 1 or 2 and a step of irradiating the discharged active energy ray-curable composition with active energy rays. Image formation method.

Images