Active energy ray-curable resin composition and cured product thereof

Abstract

To provide an active energy ray-curable type resin composition capable of obtaining a cured product having a high curing rate and excellent curl resistance, adhesiveness and solvent resistance.SOLUTION: There is provided an active energy ray-curable type resin composition which comprises a polyglycerol in which the total of the triglycerol concentration and the tetraglycerol concentration is 45 wt.% or more and each concentration of triglycerol and tetraglycerol is in the range of 10 to 70 wt.% and a (meth)acrylate of a polyglycerol alkylene oxide adduct comprising an alkylene oxide.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an active energy ray-curable resin composition and a cured product formed by curing the composition. [Background technology]

[0002] Active energy ray-curable resin compositions are fast-curing, highly productive, and can be used without solvents. Therefore, they are widely used as environmentally friendly materials in coating agents such as hard coats, lining agents, pressure-sensitive adhesives, adhesives, paints, inks, optical materials, electronic materials, medical resin materials, laminates, printed circuit boards, resist materials, semiconductor encapsulants, and the like. Active energy ray-curable resin compositions often contain multifunctional (meth)acrylates having three or more (meth)acryloyl groups to improve the surface hardness and scratch resistance of the cured film (Patent Document 1). However, these multifunctional (meth)acrylates, particularly when used as coating agents, have problems such as large cure shrinkage of the curing components, which results in a cured film that is prone to curling, as well as being brittle and prone to cracking.

[0003] Therefore, a method has been proposed in which a polyfunctional (meth)acrylate is diluted with a monofunctional (meth)acrylate or a bifunctional (meth)acrylate, as in Patent Document 2. However, the crosslinking density of the cured product made from this resin composition is reduced, which causes a problem of the inherent curability of the polyfunctional (meth)acrylate being reduced. Furthermore, Patent Document 3 discloses a method using a urethane (meth)acrylate obtained by reacting a polyfunctional (meth)acrylate with a polyisocyanate, but the cured product made from this resin composition does not have sufficient curl resistance.

[0004] Furthermore, in recent years, with growing concern about environmental issues such as global warming, there has been strong social demand, particularly for chemical manufacturers, to use plant-derived materials as alternatives to conventional petroleum-derived materials. In particular, biomass content has become important for UV inks and UV adhesives that use active energy ray-curable resins. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 06-248008 [Patent Document 2] Japanese Patent Application Laid-Open No. 2009-287017 [Patent Document 3] Japanese Patent Application Laid-Open No. 2012-229412 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide an active energy ray-curable resin composition that has a high cure rate and can give a cured product that is excellent in curl resistance, adhesion, and solvent resistance. [Means for solving the problem]

[0007] As a result of extensive research, the present inventors have solved the above-mentioned problems and completed the present invention by providing an active energy ray-curable resin composition characterized by containing a (meth)acrylate of a polyglycerin alkylene oxide adduct consisting of polyglycerin and alkylene oxide, in which the total concentration of triglycerin and tetraglycerin is 50% by weight or more and the concentrations of each of triglycerin and tetraglycerin are in the range of 10% by weight to 70% by weight. [Effects of the Invention]

[0008] By using the active energy ray-curable resin composition of the present invention, it is possible to obtain a cured product that can be cured with a small amount of radiation even in the presence of oxygen, has a high curing rate, and is excellent in curl resistance, adhesion, and solvent resistance. DETAILED DESCRIPTION OF THE INVENTION

[0009] The present invention will be described below based on an embodiment, but the scope of the present invention is not limited to this embodiment, and forms in which modifications are made within the scope that does not detract from the spirit of the present invention also belong to the present invention.

[0010] The polyglycerin used in the (meth)acrylate of the polyglycerin alkylene oxide adduct of the present invention has a triglycerin concentration and a tetraglycerin concentration of 45% by weight or more in total, and each of the triglycerin and tetraglycerin concentrations is in the range of 10% to 70% by weight, preferably a triglycerin concentration and a tetraglycerin concentration of 50% by weight or more in total, and each of the triglycerin and tetraglycerin concentrations is in the range of 10% to 70% by weight, more preferably a triglycerin concentration of 30% to 55% by weight and a tetraglycerin concentration of 10% to 40% by weight. Polyglycerol can be obtained by dehydration condensation of glycerol, synthesis using glycerol analogues such as glycidol, epichlorohydrin, and glycerol halohydrin, or recovery of synthetic glycerol from glycerol distillation residues. A common method involves adding a small amount of an alkaline catalyst to glycerol, heating the mixture to a high temperature of 200°C or higher, and then polycondensing the glycerol while removing the resulting water. The reaction involves sequential intermolecular dehydration reactions, resulting in the production of high polymers, resulting in a complex mixture of unreacted glycerol, diglycerol, triglycerol, tetraglycerol, and other components. The desired polyglycerol can then be obtained by distilling off the unreacted glycerol and diglycerol, or by further distilling the resulting polyglycerol and collecting the resulting fraction. Furthermore, the polyglycerol is derived from biomass resources, enabling inexpensive mass production, enabling the economical and stable production of active energy ray-curable resins.

[0011] The composition of polyglycerol can be determined by precisely weighing approximately 0.5 g of a polyglycerol sample and approximately 0.05 g of methyl palmitate (first-grade reagent; Kishida Chemical) as an internal standard, dissolving them in approximately 1.8 ml of pyridine (special-grade reagent; Kishida Chemical), injecting 0.2 ml of TMS-HT (reagent; Tokyo Chemical Industry Co., Ltd.) into 20 μl of this solution, allowing it to react in a hot bath, and then subjecting 1 μl of the supernatant to the analysis described below.

[0012] Gas chromatograph: GC2014 (Shimadzu Corporation) Column: OV-1 (GL Science, inner diameter 3 mm, length 1.5 m) Column temperature: 100°C to 350°C (heating rate 10°C / min) Carrier gas: Helium (50 ml / min) Injection part temperature: 350℃ Detector temperature: 350℃ Detector: FID

[0013] The polyglycerol used in the (meth)acrylate of the polyglycerol alkylene oxide adduct of the present invention preferably has an average degree of polymerization calculated from the hydroxyl value of 2.5 to 4.5, more preferably 2.5 to 3.5. In this specification, the average degree of polymerization (n) of the polyglycerol calculated from the hydroxyl value is a value calculated by terminal analysis, and is calculated from (Equation 1) and (Equation 2). (Formula 1) Molecular weight=74n+18 (Equation 2) Hydroxyl value = 56110(n+2) / molecular weight The hydroxyl value is a numerical value that indicates the number of hydroxyl groups contained in polyglycerol, and refers to the number of milligrams of potassium hydroxide required to neutralize the acetic acid required to acetylate the free hydroxyl groups contained in 1 g of polyglycerol. The number of milligrams of potassium hydroxide is calculated in accordance with the "Standard Test Methods for the Analysis of Fats, Oils, and Related Materials, 2013 Edition" compiled by the Japan Oil Chemists' Society. Commercially available polyglycerols include R-PG and PGL-S (manufactured by Sakamoto Pharmaceutical Co., Ltd.).

[0014] The alkylene oxide used in the (meth)acrylate of the polyglycerin alkylene oxide adduct of the present invention preferably has 2 to 4 carbon atoms. Examples include ethylene oxide, propylene oxide, and butylene oxide, with ethylene oxide and propylene oxide being preferred. These alkylene oxides may be used alone or in combination of two or more. The average number of alkylene oxides added per hydroxyl group of the polyglycerin raw material is preferably more than 0 and 20 or less, and more preferably 10 or less. When the average number of alkylene oxides added per hydroxyl group of the polyglycerin is within this range, a cured product with a high cure rate and high surface hardness can be obtained.

[0015] There are no particular limitations on the method for producing the (meth)acrylate of a polyglycerol alkylene oxide adduct of the present invention. Examples include a dehydration esterification method in which a specific polyglycerol is subjected to an addition reaction with an arbitrary amount of alkylene oxide by a known method, and the resulting polyglycerol alkylene oxide adduct is heated and stirred with (meth)acrylic acid while the generated water is removed from the system to produce an esterified product, and a transesterification method in which a polyglycerol alkylene oxide adduct is heated and stirred with a (meth)acrylic acid ester of a lower alcohol while the generated lower alcohol is removed from the system to produce an esterified product.

[0016] The (meth)acrylate of the polyglycerol alkylene oxide adduct of the present invention is preferably one in which two or more, and more preferably four or more, of the hydroxyl groups of the polyglycerol alkylene oxide adduct are esterified with (meth)acrylic acid. When two or more hydroxyl groups are esterified with (meth)acrylic acid, a (meth)acrylate with sufficient curability is obtained.

[0017] The polyglycerol alkylene oxide adduct (meth)acrylate of the present invention is characterized by a biomass degree of 20% or more. This allows for a reduction in greenhouse gas emissions from the active energy ray-curable resin composition. Furthermore, a high biomass degree can also reduce the amount of fossil resource materials used, such as petroleum, and is therefore beneficial in terms of sustainable resource utilization. The biomass degree is preferably 25% or more. When greenhouse gas reduction is a major priority, the biomass degree may be 30% or more. The upper limit of the biomass degree is 100%, but may be set to approximately 50% or less, taking into account the properties of the active energy ray-curable resin composition. In this specification, the term "biomass degree" refers to the weight ratio of biomass materials to the weight of the polyglycerol alkylene oxide adduct (meth)acrylate. The biomass degree of the (meth)acrylate of the polyglycerin alkylene oxide adduct can be calculated by determining the biomass degree of the raw materials that make it up, multiplying this by the weight ratio of the compound (weight ratio of the component to the total weight) to determine the total biomass amount of all components (total of the above values), and dividing this by the total weight of the (meth)acrylate of the polyglycerin alkylene oxide adduct.

[0018] Furthermore, the term "biomass material" refers to a material derived from a renewable organic resource. Typically, it refers to a material derived from a biological resource that can be sustainably reproduced in the presence of sunlight, water, and carbon dioxide. Therefore, it excludes materials derived from fossil resources that are depleted through use after mining. The biomass material may be, for example, the renewable organic resource itself, or a material obtained by chemically or biologically synthesizing the organic resource.

[0019] Although the above-mentioned biomass materials emit CO2 when burned or otherwise processed, this CO2 is typically absorbed from the atmosphere through photosynthesis during plant growth, and therefore does not substantially increase atmospheric CO2. Based on this concept, the technology disclosed herein considers the above-mentioned biomass materials to be carbon-neutral, meaning that they circulate in the global environment over a relatively short period of time and do not substantially increase or decrease carbon. Based on this concept, the use of the above-mentioned biomass materials at a predetermined ratio or higher can reduce emissions of CO2, a major greenhouse gas.

[0020] There are no particular limitations on the method for producing the active energy ray-curable resin composition of the present invention, and examples thereof include a method in which a plurality of components are mixed using equipment such as a mechanical stirrer or a magnetic stirrer.

[0021] The active energy ray-curable resin composition of the present invention can be cured by a known method using active energy rays. Examples of active energy rays include light rays such as ultraviolet rays, visible light, and infrared rays, and electromagnetic waves such as electron beams, X-rays, and gamma rays. However, curing by ultraviolet irradiation is preferred in terms of curing speed, equipment cost, and widespread use. Examples of light sources for curing by ultraviolet irradiation include high-pressure mercury lamps, metal halide lamps, xenon lamps, electrodeless discharge lamps, and LEDs.

[0022] When the active energy ray curable resin composition of the present invention is cured by ultraviolet irradiation, it is necessary to use a photopolymerization initiator. The photopolymerization initiator may be any known one, for example, benzyl ketals such as 2,2-dimethoxy-1,2-diphenylethan-1-one, α-hydroxyacetophenones such as 1-hydroxycyclohexyl phenyl ketone, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, aminoacetophenones such as 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone-1, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, bis(2,4,6-trimethylbenzoyl) ) acylphosphine oxides such as phenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, monoacylphosphine oxide, etc., benzoins such as benzoin methyl ether, benzoin ethyl ether, benzoin butyl ether, benzoin isopropyl ether, etc., benzophenones such as benzophenone, methylbenzophenone, 4,4'-bisdiethylaminobenzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, etc., thioxanthones such as 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2-isopropylthioxanthone, etc. These may be used alone or in combination of two or more.

[0023] When a photopolymerization initiator needs to be used, the amount used is 0.1 to 15% by weight, preferably 0.5 to 10% by weight, based on the total amount of the active energy ray-curable resin.

[0024] When a photopolymerization initiator is used, it can be used alone or in combination with two or more photosensitizers, such as triethanolamine, triisopropanolamine, 4,4-dimethylaminobenzophenone, 4,4-diethylaminobenzophenone, 2-dimethylaminoethylbenzoic acid, ethyl 4-dimethylaminobenzoate, (n-butoxy)ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, and 2-ethylhexyl 4-dimethylaminobenzoate.

[0025] The active energy ray-curable resin composition of the present invention is characterized by containing a (meth)acrylate of a polyglycerin alkylene oxide adduct, but one or more other compounds having an ethylenically unsaturated group can be blended in as long as the effects of the present invention are not impaired.

[0026] Among the compounds having an ethylenically unsaturated group that can be blended in the active energy ray-curable resin composition of the present invention, specific examples of monofunctional compounds having one ethylenically unsaturated group include alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate, alicyclic alkyl (meth)acrylates such as cyclohexyl (meth)acrylate and isobornyl (meth)acrylate, aralkyl (meth)acrylates such as benzyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, and the like. Examples of the polymerizable monomer include alkoxyalkyl (meth)acrylates such as ω-acrylate, dimers or higher oligomers which are Michael addition reaction products of unsaturated carboxylic acids such as (meth)acrylic acid, crotonic acid, and cinnamic acid, carboxyl group-containing (meth)acrylates such as ω-carboxypolycaprolactone mono(meth)acrylate, monohydroxyethyl phthalate (meth)acrylate, and monohydroxyethyl succinate (meth)acrylate, alkoxysilyl group-containing (meth)acrylates, vinyl monomers such as N-vinylpyrrolidone and N-vinylcaprolactam, and vinyl ethers such as triethylene glycol divinyl ether and hydroxyethyl vinyl ether.

[0027] Among the compounds having an ethylenically unsaturated group, specific examples of bifunctional compounds having two ethylenically unsaturated groups include glycol di(meth)acrylates such as ethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, and tripropylene glycol di(meth)acrylate.

[0028] Among the compounds having an ethylenically unsaturated group, specific examples of polyfunctional compounds having three or more ethylenically unsaturated groups include (meth)acrylates of alkylene oxide adducts of polyhydric alcohols such as glycerin, diglycerin, trimethylolpropane, pentaerythritol, tris(2-hydroxyethyl)isocyanurate, ditrimethylolpropane, dipentaerythritol, and xylitol, as well as oligomers such as polyester (meth)acrylates, epoxy (meth)acrylates, and urethane (meth)acrylates.

[0029] The active energy ray-curable resin composition of the present invention can be blended with organic solvents such as methyl ethyl ketone, ethanol, toluene, hexane, ethyl acetate, methyl cellosolve, etc.; non-reactive polymer resins such as polyester elastomers, polyurethane elastomers, acrylic polymers, etc.; reactive polymer resins such as polydiallyl phthalate, polydiallyl isophthalate, etc.; additives such as leveling agents, antifoaming agents, silane coupling agents, antioxidants, ultraviolet absorbers, pigments / dyes, light stabilizers, polymerization inhibitors, antistatic agents, flame retardants, etc.; inorganic fillers such as calcium carbonate, talc, silica, zirconium compounds, etc.; cellulose fiber, carbon fiber, etc., within the range that does not impair the effects of the present invention.

[0030] The form of the cured product obtained by curing the active energy ray-curable resin composition of the present invention is not particularly limited, and can be selected from various forms such as coatings, films, three-dimensional objects, etc. formed by known methods. When used by coating on a substrate, the composition can be applied to various substrates such as plastics, metals, inorganic materials, wood, paper, and composite substrates thereof. [Example]

[0031] The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following examples as long as it does not depart from the gist of the invention. In the examples, "parts" are by weight. In the examples, ethylene oxide is abbreviated as "EO."

[0032] <Synthesis of Polyglycerol EO Acrylate> Purified glycerin (manufactured by Sakamoto Pharmaceutical Co., Ltd.) and sodium hydroxide as a catalyst were placed in a four-neck flask equipped with a thermometer and a stirrer, and the mixture was reacted at 250°C under a nitrogen stream to obtain polyglycerin. This composition was then distilled under reduced pressure to obtain polyglycerin A with an average degree of polymerization of 3 and a specific composition of about 25% diglycerin or less, about 52% triglycerin, about 18% tetraglycerin, about 4% pentaglycerin, and about 1% hexaglycerin or more. Polyglycerin A and potassium hydroxide as a catalyst were then added, and an addition reaction was carried out while blowing in ethylene oxide gas to obtain a polyglycerin EO adduct. Furthermore, a reaction vessel equipped with a thermometer, stirrer, Dean-Stark apparatus, and air inlet was charged with 382.68 g (0.81 mol) of polyglycerol EO adduct, 600 g of toluene, 30.00 g of p-toluenesulfonic acid, 0.60 g of hydroquinone monomethyl ether, 0.24 g of cupric chloride, 0.60 g of sodium hypophosphite monohydrate, and 376.52 g (5.22 mol) of acrylic acid. The mixture was heated to a toluene reflux atmosphere with stirring and air blowing, and a dehydration esterification reaction was carried out over approximately 5 hours. After completion of the reaction, the mixture was washed with alkaline water and water, and the toluene in the organic layer was removed under reduced pressure to obtain 446.09 g of the acrylate of polyglycerol EO adduct (hereinafter referred to as "A1"). Similarly, A2 and A3, shown in Table 1, were obtained by varying the type of polyglycerol and the average number of EO adducts. The polyglycerin B used in A3 is a polyglycerin with an average degree of polymerization of 4 (the total of the triglycerin concentration and the tetraglycerin concentration is about 34% by weight).

[0033] [Table 1]

[0034] The viscosity and water solubility of the polyglycerol EO adduct acrylate obtained above and DPHA (dipentaerythritol hexaacrylate), a general-purpose multifunctional acrylate, were evaluated. The results are shown in Table 2.

[0035] <Viscosity> The viscosity at 25°C of the acrylates (A1) to (A3) of the polyglycerin EO adducts and DPHA was measured using an E-type rotational viscometer (HBDV-II+ProCp, manufactured by Brookfield).

[0036] <Water-soluble> Water was added to the acrylates (A1) to (A3) of the polyglycerin EO adduct and DPHA, and the maximum amount of water added that could maintain the transparency of the appearance was determined according to the following criteria. (Judgment criteria) ◎: Can dissolve 5% water. ○: 5% water can be dissolved, but the color becomes slightly dull. ×: 5% water cannot be dissolved, and separation and dullness are observed.

[0037] [Table 2]

[0038] Example 1 100 parts of the acrylate (A1) of polyglycerin EO adduct and 5 parts of 1-hydroxycyclohexyl phenyl ketone (Irgacure 184: manufactured by BASF Japan, hereinafter referred to as "Irg184") as a photopolymerization initiator were uniformly mixed and stirred to obtain an active energy ray-curable resin composition.

[0039] <Example 2> An active energy ray-curable resin composition was obtained in the same manner as in Example 1, except that the acrylate (A2) of the polyglycerol EO adduct shown in Table 1 was used instead of the acrylate (A1) of the polyglycerol EO adduct in Example 1.

[0040] <Reference example> An active energy ray-curable resin composition was obtained in the same manner as in Example 1, except that the acrylate (A3) of the polyglycerol EO adduct shown in Table 1 was used instead of the acrylate (A1) of the polyglycerol EO adduct in Example 1.

[0041] <Comparative Example> An active energy ray-curable resin composition was obtained in the same manner as in Example 1, except that DPHA was used instead of the acrylate (A1) of the polyglycerol EO adduct of Example 1.

[0042] The active energy ray-curable resin compositions obtained in Examples 1 and 2, the Reference Example, and the Comparative Example were evaluated for curability and physical properties of the cured product by the following methods. The active energy ray-curable resin compositions obtained in Examples 1 and 2, the Reference Example, and the Comparative Example were applied to a polyethylene terephthalate film (hereinafter referred to as "PET film") using a bar coater to achieve the film thickness required for each evaluation, and the applied film was then irradiated with a belt conveyor-type UV irradiation device (product name: iGrantage ECS-401GX, manufactured by iGraphics Co., Ltd.) equipped with a high-pressure mercury lamp at an irradiation dose of 500 mJ / cm in an air atmosphere. 2 , illuminance 100mW / cm 2 The cured product was then irradiated with UV light under the conditions of 23°C and 50% RH for at least 12 hours, after which it was evaluated for surface hardness, curl resistance, adhesion, solvent resistance, and water contact angle. The results are shown in Table 3.

[0043] <Curing rate> The curing rate (hereinafter referred to as "final curing rate") when the active energy ray-curable resin composition is UV-cured can be determined by measuring the C=C stretching vibration peak (1635 cm) of the acryloyl group in Fourier transform infrared spectroscopy (hereinafter referred to as "FT-IR"). -1 The FT-IR measurement was performed using a Fourier transform infrared spectrometer (Spectrum 100, manufactured by PerkinElmer Japan Co., Ltd.) equipped with a reflectance measurement accessory. From the obtained FT-IR spectrum, the C=O stretching vibration peak of the ester group (1740 cm -1 The final cure rate was calculated using the absorption peak around 1000 nm as a reference using (Equation 3) and (Equation 4). (Equation 3) Absorption peak area ratio = C=C stretching vibration peak area / C=O stretching vibration peak area (Formula 4) Final curing rate (%) = {1-(a / b)}×100 a: Accumulated irradiation dose 100mJ / cm2 Absorption peak area ratio in b: Cumulative irradiation dose 0 mJ / cm 2 Absorption peak area ratio in

[0044] <Surface hardness> The surface hardness was evaluated by pencil hardness according to JIS K5600. The surface of the cured coating film, prepared to a film thickness of 10 μm, was scratched with a pencil under a load of 750 g, and the hardest point that did not leave a scratch was recorded as the pencil hardness. The PET film used was Lumirror 100-S10 (manufactured by Toray Industries, Inc., thickness 100 μm).

[0045] <Curl resistance> A cured product prepared to a film thickness of 10 μm was cut into a 100 mm × 100 mm piece and placed on a horizontal table with the coating surface facing up. The height of the raised corners was measured. The average value was calculated, and the curling was evaluated according to the following criteria. Cosmoshine A4300 (manufactured by Toyobo Co., Ltd., thickness 100 μm) was used as the PET film. (Judgment criteria) ◎: Average height is less than 3 mm ○: Average height is 3mm or more and less than 10mm △: Average height is 10mm or more and less than 20mm ×: Average height is 20mm or more

[0046] <Adhesion> In accordance with JIS K5600, 100 squares of 1 mm squares were cut into the coating surface of a cured product prepared to a film thickness of 10 μm using a utility knife. Cellophane tape (manufactured by Nichiban Co., Ltd.) was then applied over the 100 squares, and the tape was peeled off after 1 minute. The number of squares that did not peel off was counted using a fluorescence microscope (BZ-X800, manufactured by Keyence Corporation) and evaluated according to the following criteria. Cosmoshine A4300 (manufactured by Toyobo Co., Ltd., thickness 100 μm) was used as the PET film. (Judgment criteria) 〇: The number of remaining squares is 80 or more ×: The number of remaining squares is less than 80 squares

[0047] <Solvent resistance> A drop of each of the following solvents was dropped onto the surface of a 10 μm thick cured coating prepared in accordance with JIS K5600: methanol (Kishida Chemical Co., Ltd.), acetone (Kishida Chemical Co., Ltd.), methyl ethyl ketone (Fujifilm Wako Pure Chemical Co., Ltd.), ethyl acetate (Fujifilm Wako Pure Chemical Co., Ltd.), or toluene (Kishida Chemical Co., Ltd.). After one minute, the solvent was removed and the appearance of the coating was visually inspected and rated according to the following criteria: Cosmoshine A4300 (Toyobo Co., Ltd., thickness 100 μm) was used as the PET film. (Judgment criteria) ○: No change in appearance under all conditions △: Droplet marks remain under some conditions ×: Whitening or cracking occurs under some or all conditions.

[0048] <Water contact angle> A 1.0 μL droplet of water was dropped onto the surface of a 10 μm thick cured coating using a surface tensiometer (Drop Master 500, manufactured by Kyowa Interface Science Co., Ltd.), and the contact angle 1 minute after the droplet landed was measured using the θ / 2 method. The PET film used was Lumirror 100-S10 (manufactured by Toray Industries, Inc., thickness 100 μm).

[0049] [Table 3]

[0050] The evaluation results of Examples 1 and 2 in Table 3 show that the cured product obtained from the active energy ray-curable resin composition of the present invention, which is composed of a (meth)acrylate of a polyglycerol alkylene oxide adduct, exhibits curability, curl resistance, adhesion, and solvent resistance that are equal to or better than those of the Reference Example, which uses a polyglycerol with an average degree of polymerization of 4. In particular, the curing rate is about 2.5 times higher than that of the Comparative Example, and curl resistance is also good. Furthermore, as can be seen from Table 2, the low viscosity allows for both excellent handleability and cured coating film properties.

Claims

1. A polyglycerol having a total concentration of triglycerol and tetraglycerol of 45% by weight or more, a triglycerol concentration of 30% by weight to 55% by weight, and a tetraglycerol concentration of 10% by weight to 40% by weight, the polyglycerol having an average degree of polymerization of 2.5 to 3.5; and Polyglycerin alkylene oxide adducts consisting of alkylene oxides An active energy ray-curable resin composition comprising a (meth)acrylate.

2. 2. The active energy ray-curable resin composition according to claim 1, wherein the (meth)acrylate of the polyglycerin alkylene oxide adduct has a biomass ratio of 20% or more.

3. 3. The active energy ray-curable resin composition according to claim 1, wherein the alkylene oxide in the (meth)acrylate of the polyglycerin alkylene oxide adduct has 2 to 4 carbon atoms.

4. The active energy ray-curable resin composition according to any one of claims 1 to 3, wherein the average number of alkylene oxides added to the (meth)acrylate of the polyglycerin alkylene oxide adduct is more than 0 and 10 or less per hydroxyl group of the polyglycerin.

5. A cured product formed by curing the active energy ray-curable resin composition according to any one of claims 1 to 4.

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