Photocurable resin composition, cured product, and laminate

Abstract

To provide a photocurable resin composition that can yield a cured product having a low reaction force over a wide range of compressibility (compression range).SOLUTION: The photocurable resin composition is characterized in that the cured product of the photocurable resin composition has a reaction force at 10% compression is 1 to 300 kPa, the reaction force at 50% compression of the cured product is 1 to 500 kPa, and the composition contains a hallow organic resin filler as a component (A) and does not contain a monofunctional acrylic monomer having a hydroxyl group.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a photocurable resin composition, a cured product, and a laminate. [Background technology]

[0002] BACKGROUND ART In recent years, laminated lithium ion secondary batteries have been widely used as power sources for portable devices such as multi-function mobile phones and digital cameras, with the aim of reducing their size and weight.

[0003] Japanese Patent Application Laid-Open No. 2008-235170 discloses a laminated lithium ion secondary battery in which, from the viewpoint of long-term reliability, a certain weight or more is applied in the stacking direction to fix the batteries so that they do not move relative to each other. Summary of the Invention [Problem to be solved by the invention]

[0004] Japanese Patent Application Laid-Open Publication No. 2008-235170 discloses a laminated lithium-ion secondary battery structure in which a buffer material is sandwiched between the batteries to create uniform surface pressure. However, when conventional buffer materials are used, if the compression ratio is too high, the reaction force generated by the buffer material and the expansion of the batteries themselves can cause problems such as deformation of the surface of the battery pack case.

[0005] The present invention has been made in view of the above circumstances, and has an object to provide a photocurable resin composition that can give a cured product with low repulsion over a wide range of compression ratios (compression range). Another object of the present invention is to provide a cured product obtained by curing the photocurable resin composition. Yet another object of the present invention is to provide a laminate obtained by laminating adherends using the cured product. [Means for solving the problem]

[0006] As a result of intensive research aimed at solving the above problems, the present inventors have found that, by using a photocurable resin composition described in detail below, a cured product having low repulsion can be obtained over a wide range of compression ratios (compression range), and have thus invented the present invention.

[0007] In order to achieve at least one of the above-mentioned objects, a photocurable resin composition according to one embodiment of the present invention provides a cured product having a reaction force of 1 to 300 kPa when compressed by 10% and a reaction force of 1 to 500 kPa when compressed by 50%, and includes a hollow organic resin filler as component (A) but does not include a monofunctional (meth)acrylic monomer having a hydroxyl group.

[0008] In order to achieve at least one of the above-mentioned objects, a photocurable resin composition according to another aspect of the present invention is a photocurable resin composition that does not contain a monofunctional (meth)acrylic monomer having a hydroxyl group and contains a hollow organic resin filler as component (A), and the cured product of the photocurable resin composition has a reaction force of 1 to 300 kPa when compressed by 10% and a reaction force of 1 to 500 kPa when compressed by 50%. DETAILED DESCRIPTION OF THE INVENTION

[0009] The following describes embodiments of the present invention. However, the present disclosure is not limited to the following embodiments. In this specification, "X to Y" means a range including the numerical values ​​(X and Y) before and after it as the lower and upper limits, respectively, and means "X or more and Y or less." Furthermore, unless otherwise specified, concentrations and % represent mass concentration and mass %, respectively, and ratios are mass ratios unless otherwise specified. Furthermore, unless otherwise specified, operations and measurements of physical properties, etc. are performed under conditions of room temperature (20 to 25°C) and relative humidity 40 to 55% RH. Furthermore, "A and / or B" means A and B, respectively, and combinations thereof.

[0010] [Photocurable resin composition] A photocurable resin composition according to one embodiment of the present invention (hereinafter also referred to as "photocurable resin composition" or simply "resin composition") is characterized in that the reaction force of the cured product when compressed by 10% is 1 to 300 kPa and the reaction force of the cured product when compressed by 50% is 1 to 500 kPa, and the composition contains a hollow organic resin filler (A) as component (A) but does not contain a monofunctional (meth)acrylic monomer having a hydroxyl group.

[0011] According to one aspect of the present invention, a cured product having low repulsion can be obtained over a wide range of compression ratios. That is, when a cured product obtained using the photocurable resin composition is compressed over a wide range of compression ratios, the repulsion generated in the cured product can be reduced. Specifically, the cured product obtained using the photocurable resin composition has a repulsion of 1 to 300 kPa at 10% compression and a repulsion of 1 to 500 kPa at 50% compression.

[0012] Thus, with the photocurable resin composition according to the present invention, when the cured product is compressed over a wide range of compression ratios, the reaction force generated in the cured product is small. Although the details of this mechanism are unknown, it is thought that the hollow organic resin filler contained as component (A) is softer than, for example, glass fillers, and because it is hollow, it acts as a buffer material, which reduces the reaction force generated when the cured product is compressed (especially when compressed at a high compression ratio). Furthermore, although the detailed mechanism is unknown, when a monofunctional (meth)acrylic monomer having a hydroxyl group is contained, the photocurability is reduced and a good cured product cannot be obtained (see Comparative Examples 3 and 4 described below).

[0013] The above mechanism is based on speculation, and the correctness of the mechanism does not affect the technical scope of the present invention.

[0014] A photocurable resin composition according to a preferred embodiment of the present invention further contains the following components (B) to (D): (B) Component: Monofunctional urethane (meth)acrylate Component (C): a monofunctional (meth)acrylic monomer other than the component (B) Component (D): Photoradical polymerization initiator.

[0015] Moreover, a photocurable resin composition according to a preferred embodiment of the present invention further contains, as component (E), a plasticizer having no (meth)acryloyl group.

[0016] Furthermore, the photocurable resin composition according to a preferred embodiment of the present invention further contains a di- or higher functional (meth)acrylic monomer as component (F).

[0017] Components contained in the photocurable resin composition according to one embodiment of the present invention will be described below.

[0018] <Monofunctional (meth)acrylic monomers having a hydroxyl group> The photocurable resin composition according to the present invention does not contain a monofunctional (meth)acrylic monomer having a hydroxyl group. By adopting such a configuration, the photocurability of the photocurable resin composition can be improved. On the other hand, if the photocurable resin composition contains a monofunctional (meth)acrylic monomer having a hydroxyl group, photocuring does not proceed sufficiently, making it impractical (see Comparative Examples 3 and 4 described below).

[0019] In addition, the fact that the composition does not contain a monofunctional (meth)acrylic monomer having a hydroxyl group is 1 H NMR and 13 This can be determined using C NMR.

[0020] In this specification, "not containing" a certain component means "substantially not containing" the component, and includes embodiments in which the target substance is contained as a contaminant. Specifically, this means that the target substance may be present in a proportion of 0.1% by mass or less (lower limit: 0% by mass) relative to the total mass of the composition.

[0021] As used herein, the term "(meth)acrylic monomer" refers to a monomer having one or more (meth)acryloyl groups. The term "(meth)acryloyl" encompasses both acryloyl and methacryloyl. Thus, for example, the term "(meth)acryloyl group" encompasses both an acryloyl group (HC=CH-C(=O)-) and a methacryloyl group (HC=C(CH)-C(=O)-). Similarly, the term "(meth)acrylate" encompasses both acrylate and methacrylate, and the term "(meth)acrylic" encompasses both acrylic and methacrylic.

[0022] Furthermore, a "monofunctional (meth)acrylic monomer having a hydroxyl group" refers to a monomer having one or more hydroxyl groups and one acryloyl group or one methacryloyl group. Examples of such monomers include 2-hydroxyethyl (meth)acrylate.

[0023] <Component (A)> The component (A) contained in the photocurable resin composition is a hollow resin filler (hollow organic resin filler). A hollow resin filler is a particle formed of a resin and has a hollow portion. By including such a component (A), the cured product obtained by curing the photocurable resin composition according to the present invention generates a small reaction force even when compressed over a wide range of compression ratios (particularly high compression ratios). Furthermore, by combining the component (A) with other components (preferably components (B) to (F)) described below, not only can a cured product generating such a small reaction force be obtained, but the photocurable resin composition can also be rapidly cured by photocuring.

[0024] The shape of the hollow resin filler is not particularly limited and may be any shape, such as spherical, needle-like, fibrous, or plate-like. However, a spherical shape is preferred from the viewpoints of not only reducing the reaction force during compression of the cured product but also facilitating uniform dispersion in the resin composition. Here, "spherical" refers to a shape with an aspect ratio of 1.0 to 2.0, preferably 1.0 to 1.5, but does not necessarily mean a perfect sphere. In the case of a spherical filler, the aspect ratio refers to the ratio of the major axis to the minor axis.

[0025] The average particle size of the hollow resin filler as component (A) is not particularly limited, but is preferably 5 to 300 μm, more preferably 10 to 200 μm, even more preferably 50 to 150 μm, particularly preferably 60 to 130 μm, and most preferably 70 to 100 μm. The average particle size of component (A) can be determined using a particle size distribution analyzer employing analytical means such as laser diffraction. By ensuring that the average particle size of component (A) falls within the above range, a cured product with low repulsion can be obtained over an even wider range of compression ratios (compression range).

[0026] Component (A) is formed from a resin (organic resin). The resin constituting component (A) is not particularly limited, but is preferably a thermoplastic resin, more preferably a polymer (homopolymer) of at least one monomer selected from the group consisting of vinylidene chloride, acrylonitrile, methacrylonitrile, acrylic acid esters (acrylates), and methacrylic acid esters (methacrylates), or a copolymer of two or more monomers selected from the above. These resins may be used alone or in combination of two or more. From the viewpoint of the toughness (strength) of the hollow resin filler, the resin constituting the hollow resin filler is preferably a polymer (polyacrylonitrile resin) or copolymer containing acrylonitrile as a constituent unit, more preferably a copolymer containing acrylonitrile as a constituent unit, and particularly preferably an acrylonitrile-methacrylonitrile-methyl methacrylate copolymer. That is, the hollow resin filler is preferably composed of an acrylonitrile-methacrylonitrile-methyl methacrylate copolymer.

[0027] The hollow resin filler as component (A) is preferably surface-treated to improve compatibility with other components such as components (B) to (F) described below. The type of surface treatment is not particularly limited, but the hollow resin filler may be surface-treated with a silane coupling agent, fatty acid, or the like, or may have calcium carbonate attached to its surface. Of these, it is more preferable that component (A) is a hollow resin filler with calcium carbonate attached to its surface. These types of surface treatment may be used alone or in combination.

[0028] The true specific gravity of component (A) is not particularly limited, but is, for example, 0.03 to 0.50 g / cm 3 It is preferable that the concentration is 0.05 to 0.40 g / cm 3 It is more preferable that the concentration is 0.07 to 0.30 g / cm 3The true specific gravity of component (A) can be determined in accordance with JIS Z 8807:2012. When the true specific gravity of component (A) is within the above range, a cured product can be obtained that exhibits low repulsion over an even wider range of compression ratios (compression range).

[0029] The content of component (A) is not particularly limited, but is preferably 3 to 80 parts by mass, more preferably 5 to 50 parts by mass, particularly preferably 8 to 30 parts by mass, and most preferably 10 to 20 parts by mass, relative to 100 parts by mass of the total mass of the photocurable resin composition.

[0030] Furthermore, the content of component (A) is not particularly limited, but is preferably 3 to 70 parts by mass, more preferably 5 to 60 parts by mass, particularly preferably 10 to 50 parts by mass, and most preferably 20 to 30 parts by mass, relative to 100 parts by mass of the total of components (B) and (C) described below.

[0031] The hollow resin filler used as component (A) may be either a synthetic product or a commercially available product. Examples of commercially available products of component (A) include EMC-40B, EMC-80B, and EMC-120α (manufactured by Nippon Fillite Co., Ltd.).

[0032] The hollow resin filler as component (A) may be used alone or in combination of two or more types. When two or more types are used in combination, the content of component (A) refers to the total amount.

[0033] <(B) component> The photocurable resin composition according to the present invention preferably contains a monofunctional urethane (meth)acrylate as component (B). By combining component (B) with component (A), the reaction force generated in the cured product can be reduced even when the cured product is compressed over a wide range of compression ratios (compression range).

[0034] Here, urethane (meth)acrylate refers to an ester compound having a urethane bond formed by reacting an isocyanate group with a hydroxy group, and a (meth)acryloyl group. That is, urethane (meth)acrylate refers to a (meth)acrylic acid ester having a urethane bond. In the monofunctional urethane (meth)acrylate used as component (B), the number of urethane bonds may be one or more per molecule, and the number of (meth)acryloyl groups per molecule is one. The (meth)acryloyl group may be contained in the compound in the form of a (meth)acryloyloxy group. The use of a urethane (meth)acrylate having two or more (meth)acryloyl groups is undesirable because it increases the reaction force of the cured product of the photocurable resin composition. Furthermore, from the viewpoint of reducing the compression set of the resulting cured product, the (meth)acryloyl group contained in component (B) is preferably an acryloyl group. Here, the phrase "low compression set" of a material refers to a material having a high recovery force when compressed for a long period of time. Such properties are important when the photocurable resin composition (and its cured product) according to the present invention is used as a buffer material for the laminate-type lithium-ion secondary battery described above. Since the reactivity of acryloyl groups is higher than that of methacryloyl groups, it is believed that the compression set is reduced as described above when the (meth)acryloyl groups contained in component (B) are acryloyl groups.

[0035] The monofunctional urethane (meth)acrylate as component (B) is preferably a monofunctional urethane (meth)acrylate oligomer in order to improve the desired effect. In this specification, the term "oligomer" refers to a polymer in which two to several tens of monomer units (including monomer units other than (meth)acrylate monomers) are repeated, and which has a weight-average molecular weight of 1,000 (1,000) or more.

[0036] The monofunctional urethane (meth)acrylate as component (B) may contain a structure other than a urethane bond and a (meth)acryloyl group, such as a polyester skeleton, a polycaprolactone skeleton, a polycarbonate skeleton, or a polyether skeleton. One or more of these skeletons may be contained in a single molecule. From the viewpoint of further enhancing the desired effects, it is preferable that component (B) have a polyether skeleton. In this specification, the term "polyether skeleton" refers to a skeleton having an alkylene oxide as a repeating unit, such as polyethylene oxide, polypropylene oxide, or polybutylene oxide.

[0037] From the viewpoint of further improving the intended effect, the (B) component is preferably a monofunctional urethane (meth)acrylate oligomer having a polyether skeleton (a polyether-based monofunctional urethane (meth)acrylate oligomer), and more preferably a monofunctional urethane acrylate oligomer having a polyether skeleton.

[0038] On the other hand, from the viewpoint of photocurability, the component (B) is preferably a monofunctional urethane (meth)acrylate that does not have a hydroxyl group.

[0039] The monofunctional urethane (meth)acrylate (monofunctional urethane (meth)acrylate oligomer) used as component (B) may be either a synthetic product or a commercially available product.

[0040] The method for producing component (B) is not particularly limited, but examples thereof include a method of reacting a polyol compound having a hydroxyl group with a (meth)acrylate having an isocyanate group, or a method of reacting a polyol compound having a hydroxyl group, a polyisocyanate compound, and a (meth)acrylate having a hydroxyl group, etc. These reactions are preferably carried out in the presence of a catalyst.

[0041] The polyol compound having a hydroxyl group is not particularly limited, but examples thereof include polyester polyols, polycarbonate polyols, polyether polyols such as polyethylene oxide, polypropylene oxide, and polybutylene glycol. The number of repeating units of alkylene oxide contained in the polyether polyol is not particularly limited, but is, for example, 3 to 500, more preferably 5 to 100, and particularly preferably 10 to 50.

[0042] The (meth)acrylate having an isocyanate group is not particularly limited, but examples thereof include 2-isocyanatoethyl (meth)acrylate and 2-(2-(meth)acryloyloxyethyloxy)ethyl isocyanate.

[0043] The polyisocyanate compound is not particularly limited, and examples thereof include aromatic polyisocyanates such as 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, tetramethylxylylene diisocyanate, diphenylmethane diisocyanate, naphthalene-1,5-disocyanate, and triphenylmethane triisocyanate; isophorone diisocyanate, bis( Examples of suitable polyisocyanates include alicyclic polyisocyanates such as 4-isocyanatocyclohexyl)methane, 1,3-bis(isocyanatomethyl)cyclohexane, 1,4-bis(isocyanatomethyl)cyclohexane, norbornane diisocyanate, and bicycloheptane triisocyanate; and linear or branched aliphatic polyisocyanates such as hexamethylene diisocyanate, 1,3,6-hexamethylene triisocyanate, and 1,6,11-undeca triisocyanate. Among these, from the viewpoint of obtaining a flexible cured product, it is preferable that the polyisocyanate compound be selected from linear or branched aliphatic polyisocyanates and alicyclic polyisocyanates. These compounds may be used alone or in combination.

[0044] The (meth)acrylate having a hydroxyl group is not particularly limited, but examples thereof include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxycyclohexyl (meth)acrylate, 1,6-hexanediol mono(meth)acrylate, neopentyl glycol mono(meth)acrylate, (poly)ethylene glycol mono(meth)acrylate, (poly)propylene glycol mono(meth)acrylate, and pentaerythritol tri(meth)acrylate. Among these, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and 4-hydroxycyclohexyl (meth)acrylate are preferred from the viewpoint of obtaining a cured product with excellent flexibility. These may be used alone or in combination.

[0045] Examples of catalysts used in the synthesis of component (B) include lead oleate, antimony trichloride, triphenylaluminum, trioctylaluminum, tetrabutyltin, dibutyltin dilaurate, copper naphthenate, zinc naphthenate, zinc octylate, zinc octenate, zirconium naphthenate, cobalt naphthenate, tetra-n-butyl-1,3-diacetyloxydistannoxane, triethylamine, 1,4-diaza[2,2,2]bicyclooctane, and N-ethylmorpholine. Among these, dibutyltin dilaurate, zinc naphthenate, zinc octylate, and zinc octenate are preferred because they cure rapidly even with a small cumulative dose of irradiated light and produce a cured product with low elasticity. The amount of these catalysts added is preferably 0.0001 to 10 parts by mass per 100 parts by mass of the total mass of the reactants. The reaction temperature is usually 10 to 100°C, and it is particularly preferred to carry out the reaction at 30 to 90°C.

[0046] The weight-average molecular weight of component (B) is not particularly limited. Because photocuring allows for rapid production of a cured product that exhibits low repulsion over a wide range of compression ratios (compression range), the weight-average molecular weight of component (B) is preferably, for example, 1,000 to 300,000 (1,000 to 300,000), more preferably 3,000 to 50,000 (3,000 to 50,000), and particularly preferably 5,000 to 40,000 (5,000 to 40,000). Unless otherwise specified, the weight-average molecular weight used herein is a value calculated using size exclusion chromatography (SEC) in terms of standard polystyrene.

[0047] The content of component (B) is not particularly limited, but is preferably 20 to 90 parts by mass, more preferably 30 to 85 parts by mass, even more preferably 40 to 80 parts by mass, particularly preferably 50 to 75 parts by mass, and most preferably 60 to 70 parts by mass, relative to 100 parts by mass of the total of component (B) and component (C), which will be described later. By keeping the content within the above range, a photocurable resin composition can be obtained that can more quickly obtain a cured product by photocuring and that can provide a cured product with low repulsion over a wide range of compression ratios (compression range).

[0048] The monofunctional urethane (meth)acrylate as component (B) may be used alone or in combination of two or more. When two or more types are used in combination, the content of component (B) refers to the total amount.

[0049] <(C) component> The photocurable resin composition according to the present invention preferably contains, as component (C), a monofunctional (meth)acrylic monomer other than component (B). By combining component (C) with component (A), a cured product can be obtained quickly by photocuring, and the cured product can have low repulsion over a wide range of compression ratios (compression range).

[0050] Here, the monofunctional (meth)acrylic monomer is a compound having one (meth)acryloyl group. The (meth)acryloyl group may be contained in the monomer in the form of a (meth)acryloyloxy group. Note that compounds having one or more urethane bonds and one (meth)acryloyl group per molecule (however, ester compounds) are included in the above-mentioned component (B), but are not included in the component (C).

[0051] Furthermore, for the purpose of improving photocurability, the (meth)acryloyl group contained in component (C) is preferably an acryloyl group, which also has the advantage of increasing the reaction rate and reducing the compression set of the resulting cured product.

[0052] The monofunctional (meth)acrylic monomer as component (C) is preferably a monofunctional (meth)acrylate monomer (i.e., an ester compound having one (meth)acryloyloxy group, a (meth)acrylic acid ester) in order to improve the desired effect.

[0053] Component (C) may contain a structure other than a (meth)acryloyl group. From the viewpoint of further improving the intended effects, it is preferable that component (C) has a polyether skeleton as such a structure. The definition of "polyether skeleton" is as described in the section on component (B) above. The number of repeating units of alkylene oxide constituting the polyether skeleton is not particularly limited, but is, for example, 2 to 300, preferably 2 to 100, more preferably 2 to 30, and particularly preferably 2 to 10. Furthermore, the number of carbon atoms constituting the alkylene oxide is not particularly limited, but the number of carbon atoms in one repeating unit is preferably 2 to 10, more preferably 2 to 5, particularly preferably 2 to 4, and most preferably 2. That is, the polyether skeleton contained in component (C) is preferably a polyethylene oxide skeleton.

[0054] The molecular weight of component (C) is not particularly limited, but from the viewpoint of improving the curability of the photocurable resin composition, it is preferably less than 1000, more preferably 500 or less, and particularly preferably 300 or less. Furthermore, from the viewpoint of excellent compatibility with component (B), the molecular weight of the compound of component (C) is preferably more than 100, more preferably 130 or more. In this specification, the molecular weight of a compound (low molecular weight compound) can be measured by a known method such as gas chromatography-mass spectrometry (GC-MS). Furthermore, if it is not possible to measure by this method, the molecular weight can be determined by identifying the structure of the compound by a method such as NMR and performing calculations based on the structure.

[0055] On the other hand, from the viewpoint of photocurability, component (C) is preferably a monofunctional (meth)acrylic monomer having no hydroxyl group, more preferably a monofunctional (meth)acrylate monomer having no hydroxyl group, and particularly preferably a monofunctional acrylate monomer having no hydroxyl group.

[0056] The component (C) is not particularly limited, and examples thereof include methoxydiethylene glycol mono(meth)acrylate, methoxytriethylene glycol mono(meth)acrylate, methoxytetraethylene glycol mono(meth)acrylate, methoxypentaethylene glycol mono(meth)acrylate, methoxyhexaethylene glycol mono(meth)acrylate, methoxyheptaethylene glycol mono(meth)acrylate, methoxyhectaethylene glycol mono(meth)acrylate, methoxyoctaethylene glycol mono(meth)acrylate, methoxynonaethylene glycol mono(meth)acrylate, methoxydecaethylene glycol mono(meth)acrylate, methoxytripropylene glycol mono(meth)acrylate, methoxytetrapropylene glycol mono(meth)acrylate, methoxypentapropylene glycol mono(meth)acrylate, methoxyhexapropylene glycol mono(meth)acrylate, methoxyheptapropylene glycol mono(meth)acrylate, methoxyhectapropylene glycol mono(meth)acrylate, Methoxyoctapropylene glycol mono(meth)acrylate, methoxynonapropylene glycol mono(meth)acrylate, methoxydecapropylene glycol mono(meth)acrylate, methoxytributylene glycol mono(meth)acrylate, methoxytetrabutylene glycol mono(meth)acrylate, methoxypentabtylene glycol mono(meth)acrylate, methoxyhexabtylene glycol mono(meth)acrylate, methoxyheptabtylene glycol mono(meth)acrylate, methoxyhectabtylene glycol Lithium mono(meth)acrylate, methoxyoctabutylene glycol mono(meth)acrylate, methoxynonabutylene glycol mono(meth)acrylate, methoxydecabutylene glycol mono(meth)acrylate, ethoxydiethylene glycol mono(meth)acrylate, ethoxytriethylene glycol mono(meth)acrylate, ethoxytetraethylene glycol mono(meth)acrylate, ethoxypentaethylene glycol mono(meth)acrylate, ethoxyhexaethylene glycol mono(meth)acrylate,Ethoxyheptaethylene glycol mono(meth)acrylate, ethoxyhexaethylene glycol mono(meth)acrylate, ethoxyoctaethylene glycol mono(meth)acrylate, ethoxynonaethylene glycol mono(meth)acrylate, ethoxydecaethylene glycol mono(meth)acrylate, ethoxytripropylene glycol mono(meth)acrylate, ethoxytetrapropylene glycol mono(meth)acrylate, ethoxypentapropylene glycol mono(meth)acrylate, ethoxyhexapropylene glycol mono(meth)acrylate, ethoxyheptapropylene glycol mono(meth)acrylate, ethoxyhexapropylene glycol mono(meth)acrylate, ethoxyoctapropylene glycol butylene glycol mono(meth)acrylate, ethoxynonapropylene glycol mono(meth)acrylate, ethoxydecapropylene glycol mono(meth)acrylate, ethoxytributylene glycol mono(meth)acrylate, ethoxytetrabutylene glycol mono(meth)acrylate, ethoxypentabtylene glycol mono(meth)acrylate, ethoxyhexabtylene glycol mono(meth)acrylate, ethoxyheptabtylene glycol mono(meth)acrylate, ethoxyhexabtylene glycol mono(meth)acrylate, ethoxyoctabtylene glycol mono(meth)acrylate, ethoxynonabtylene glycol mono(meth)acrylate, ethoxydecabutylene glycol mono(meth)acrylate, and the like. Among these, ethoxydiethylene glycol mono(meth)acrylate, ethoxytriethylene glycol mono(meth)acrylate, ethoxytetraethylene glycol mono(meth)acrylate, ethoxypentaethylene glycol mono(meth)acrylate, ethoxyhexaethylene glycol mono(meth)acrylate, ethoxyheptaethylene glycol mono(meth)acrylate, ethoxyhexaethylene glycol mono(meth)acrylate, ethoxyoctaethylene glycol mono(meth)acrylate, ethoxynonaethylene glycol mono(meth)acrylate, ethoxydecaethylene glycol mono(meth)acrylate, ethoxytripropylene glycol mono(meth)acrylate,Ethoxytetrapropylene glycol mono(meth)acrylate, ethoxypentapropylene glycol mono(meth)acrylate, ethoxyhexapropylene glycol mono(meth)acrylate, ethoxyheptapropylene glycol mono(meth)acrylate, ethoxyhexapropylene glycol mono(meth)acrylate, ethoxyoctapropylene glycol mono(meth)acrylate, ethoxynonapropylene glycol mono(meth)acrylate, ethoxydecapropylene glycol mono(meth)acrylate, ethoxytributylene glycol Cholesterol mono(meth)acrylate, ethoxytetrabutylene glycol mono(meth)acrylate, ethoxypentabtylene glycol mono(meth)acrylate, ethoxyhexabtylene glycol mono(meth)acrylate, ethoxyheptabtylene glycol mono(meth)acrylate, ethoxyhexabtylene glycol mono(meth)acrylate, ethoxyoctabtylene glycol mono(meth)acrylate, ethoxynonabtylene glycol mono(meth)acrylate, and ethoxydecabutylene glycol mono(meth)acrylate are preferred. These can be used alone or in combination of two or more.

[0057] The content of component (C) is not particularly limited, but is preferably in the range of 10 to 80 parts by mass, more preferably 20 to 70 parts by mass, even more preferably 25 to 60 parts by mass, and particularly preferably 30 to 50 parts by mass, per 100 parts by mass of the total of components (B) and (C). By keeping the content within the above range, a photocurable resin composition can be obtained that can more quickly obtain a cured product by photocuring and that can provide a cured product with low repulsion over a wide range of compression ratios (compression range).

[0058] The content (total) of the (B) component and the (C) component is not particularly limited, but is preferably 30 to 90 parts by mass, more preferably 40 to 80 parts by mass, and particularly preferably 50 to 70 parts by mass, relative to 100 parts by mass of the total mass of the photocurable resin composition.

[0059] The monofunctional (meth)acrylate monomer as component (C) may be used alone or in combination of two or more. When two or more types are used in combination, the content of component (C) refers to the total amount.

[0060] <(D) component> The photocurable resin composition according to the present invention preferably contains a photoradical polymerization initiator as component (D). Component (D) can be a compound that generates radical species upon irradiation with active energy rays such as visible light, ultraviolet light, or electron beams. Examples of such photoradical polymerization initiators include acetophenone-based photoradical polymerization initiators, benzoin-based photoradical polymerization initiators, benzophenone-based photoradical polymerization initiators, thioxanthone-based photoradical polymerization initiators, acylphosphine oxide-based photoradical polymerization initiators, and titanocene-based photoradical polymerization initiators. Among these, component (D) is preferably an acetophenone-based photoradical polymerization initiator and / or an acylphosphine oxide-based photoradical polymerization initiator, and more preferably an acetophenone-based photoradical polymerization initiator, because these initiators provide a photocurable resin composition with a fast curing rate even with a small cumulative light dose. These initiators can be used alone or in combination of two or more.

[0061] Examples of acetophenone-based photoradical polymerization initiators include, but are not limited to, diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, benzyl dimethyl ketal, 4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)ketone, 1-hydroxy-cyclohexyl-phenyl-ketone, 2-methyl-2-morpholino(4-thiomethylphenyl)propan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone, and 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone oligomer. Commercially available acetophenone-based photoradical polymerization initiators include Omnirad (registered trademark, the same applies hereinafter) 184, Omnirad 1173, Omnirad 2959, Omnirad 127 (manufactured by IGM Resins BV), and ESACURE (registered trademark) KIP-150 (manufactured by IGM Resins BV).

[0062] Examples of acylphosphine oxide-based photoradical polymerization initiators include, but are not limited to, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, etc. Commercially available acylphosphine oxide-based photoradical polymerization initiators include Omnirad TPO, Omnirad819, and Omnirad819DW (manufactured by IGM Resins BV).

[0063] The content of component (D) is not particularly limited, but is preferably 0.1 to 15 parts by mass, more preferably 0.3 to 7.0 parts by mass, particularly preferably 0.5 to 5.0 parts by mass, and most preferably 1.0 to 3.0 parts by mass, relative to 100 parts by mass of the total of components (B) and (C). By keeping the content within the above range, a photocurable resin composition can be obtained that can give a cured product with low repulsion over an even wider range of compression ratios (compression range).

[0064] The photoradical polymerization initiator as component (D) may be used alone or in combination of two or more. When two or more types are used in combination, the content of component (D) refers to the total amount.

[0065] <(E) component> The photocurable resin composition according to the present invention preferably contains, as component (E), a plasticizer that does not have a (meth)acryloyl group. The use of a plasticizer that does not have a (meth)acryloyl group reduces the reaction force generated in the resulting cured product over a wide range of compression ratios (compression ranges). By combining component (E) with component (A), a photocurable resin composition can be obtained that rapidly produces a cured product upon photocuring and that exhibits low reaction force over a wide range of compression ratios (compression ranges).

[0066] The plasticizer as component (E) preferably has a polyether skeleton to improve the desired effect. The definition of "polyether skeleton" is as described in the section on component (B) above. There are no particular restrictions on the number of carbon atoms constituting the alkylene oxide, but the number of carbon atoms in one repeating unit is preferably 2 to 10, more preferably 2 to 5, particularly preferably 2 to 4, and most preferably 3. In other words, the polyether skeleton contained in component (E) is preferably a polypropylene oxide skeleton.

[0067] The number of repeating units of alkylene oxide constituting the polyether skeleton is not particularly limited, but is, for example, 3 to 300, more preferably 5 to 100, particularly preferably 10 to 60, and most preferably 20 to 50.

[0068] The number-average molecular weight of component (E) is not particularly limited, but is, for example, 200 to 30,000, preferably 350 to 10,000, particularly preferably 500 to 5,000, and most preferably 1,000 to 3,000. Unless otherwise specified, the number-average molecular weight used herein is a value calculated using size exclusion chromatography (SEC) in terms of standard polystyrene. By keeping the number-average molecular weight within the above range, a photocurable resin composition can be obtained that can more quickly produce a cured product by photocuring and that exhibits low repulsion over a wide range of compression ratios (compression ranges).

[0069] Examples of plasticizers that can be used as component (E) include polyols and condensates thereof, such as glycerin, diglycerin, triglycerin, ethylene glycol, propylene glycol, and polyethylene glycol.

[0070] The plasticizer used as component (E) may be either a synthetic product or a commercially available product. Examples of commercially available products for component (E) include, but are not limited to, PEG#300, PEG#400, PEG#600, PEG#1000, PEG#1500, PEG#15400, PEG#2000, PEG#4000, PEG#6000, PEG#1100, PEG#2000, and Uniol® D-700, D-1000, D1200, D2000, D4000, PB-500, PB-700, PB-1000, and PB-2000 (manufactured by NOF Corporation).

[0071] The content of component (E) is not particularly limited, but is preferably 20 to 200 parts by mass, more preferably 25 to 150 parts by mass, particularly preferably 30 to 100 parts by mass, and most preferably 35 to 70 parts by mass, per 100 parts by mass of the total of components (B) and (C). By keeping the content within the above range, a photocurable resin composition can be obtained that can more quickly obtain a cured product by photocuring and that can provide a cured product with low repulsion over a wide range of compression ratios (compression range).

[0072] The plasticizer as component (E) may be used alone or in combination of two or more types. When two or more types are used in combination, the content of component (E) refers to the total amount.

[0073] <(F) Component> The photocurable resin composition according to the present invention preferably contains a difunctional or higher polyfunctional (meth)acrylic monomer as component (F). By combining component (F) with component (A), a photocurable resin composition can be obtained that rapidly cures to a cured product and exhibits low repulsion over a wide range of compression ratios (compression ranges).

[0074] Here, the polyfunctional (meth)acrylic monomer is a compound having two or more (meth)acryloyl groups. The (meth)acryloyl groups may be contained in the monomer in the form of (meth)acryloyloxy groups.

[0075] The number of (meth)acryloyl groups contained in the polyfunctional (meth)acrylic monomer as component (F) is not particularly limited as long as it is two or more, but since a photocurable resin composition with a fast curing rate can be obtained even with a small cumulative light dose, it is preferably three or more (trifunctional or more), more preferably four or more (tetrafunctional or more), and particularly preferably five or more (pentafunctional or more). Meanwhile, the upper limit of the number of (meth)acryloyl groups is not particularly limited, but is, for example, eight or less (octafunctional or less). Furthermore, for the purposes of improving photocurability and reducing the compression set of the resulting cured product, the (meth)acryloyl groups contained in component (F) are preferably acryloyl groups.

[0076] In order to improve the desired effects, the polyfunctional (meth)acrylic monomer as component (F) is preferably a polyfunctional (meth)acrylate monomer (i.e., an ester compound having two or more (meth)acryloyloxy groups, or a (meth)acrylic acid ester). The preferred number of (meth)acryloyl groups contained in the polyfunctional (meth)acrylate monomer is the same as above.

[0077] The molecular weight of component (F) is not particularly limited, but from the viewpoint of improving the curability of the photocurable resin composition, it is preferably less than 1000, and more preferably not more than 600. Furthermore, from the viewpoint of excellent compatibility with component (A), the molecular weight of the compound of component (F) is preferably more than 200, and more preferably 300 or more.

[0078] On the other hand, from the viewpoint of photocurability, the component (F) is preferably a polyfunctional (meth)acrylic monomer having no hydroxyl groups, more preferably a polyfunctional (meth)acrylate monomer having no hydroxyl groups, and particularly preferably a polyfunctional acrylate monomer having no hydroxyl groups.

[0079] The component (F) is not particularly limited, but examples thereof include tetrafunctional (meth)acrylate monomers such as ditrimethylolpropane tetra(meth)acrylate and pentaerythritol tetra(meth)acrylate; pentafunctional (meth)acrylate monomers such as dipentaerythritol monohydroxypenta(meth)acrylate and alkyl-modified dipentaerythritol penta(meth)acrylate; and hexafunctional (meth)acrylate monomers such as dipentaerythritol hexa(meth)acrylate. Among these, dipentaerythritol monohydroxypenta(meth)acrylate, alkyl-modified dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexa(meth)acrylate are preferred. These monomers can be used alone or in combination of two or more.

[0080] The content of component (F) is not particularly limited, but is preferably in the range of 0.1 to 15 parts by mass, more preferably 0.2 to 5 parts by mass, and particularly preferably 0.3 to 3 parts by mass, per 100 parts by mass of the total of components (B) and (C). By keeping the content within the above range, a photocurable resin composition can be obtained that can more quickly give a cured product by photocuring and that gives a cured product with low repulsion over a wide range of compression ratios (compression range).

[0081] The polyfunctional (meth)acrylic monomer as component (F) may be used alone or in combination of two or more. When two or more types are used in combination, the content of component (F) refers to the total amount.

[0082] <(G) component> The photocurable resin composition according to the present invention preferably contains an inorganic filler as component (G). Component (G) is not particularly limited, but examples include glass, fumed silica, alumina, talc, mica, ceramics, silicone rubber powder, calcium carbonate, aluminum hydroxide, aluminum nitride, carbon powder, kaolin clay, dried clay minerals, and dried diatomaceous earth. Among these, fumed silica and talc are preferred for the purpose of obtaining a photocurable resin composition that can produce a cured product with low repulsion over a wide range of compression ratios (compression ranges). These can be used alone or in combination of two or more.

[0083] For the purpose of obtaining a photocurable resin composition that can produce a cured product with low repulsion over a wide range of compression ratios (compression range), the fumed silica is preferably hydrophobized with at least one surface treatment agent selected from the group consisting of organochlorosilanes, dimethylsilicones, and hexamethyldisilazanes. Specific examples of silica include Aerosil (registered trademark) R974, R972, R972V, R972CF, R805, R812, R812S, R816, R8200, RY200, RX200, RY200S, and R202 (manufactured by Nippon Aerosil). These can be used alone or in combination of two or more.

[0084] The content of component (G) is not particularly limited, but is preferably in the range of 0.01 to 100 parts by mass, more preferably 0.1 to 50 parts by mass, particularly preferably 0.5 to 20 parts by mass, and particularly preferably 3 to 10 parts by mass, per 100 parts by mass of the combined total of components (B) and (C). By keeping the content within the above range, a photocurable resin composition can be obtained that can give a cured product with low repulsion over an even wider range of compression ratios (compression range).

[0085] The inorganic filler as component (G) may be used alone or in combination of two or more. When two or more types are used in combination, the content of component (G) refers to the total amount.

[0086] <Optional ingredients> The photocurable resin composition according to the present invention may further contain additives such as epoxy-modified (meth)acrylate oligomers (excluding monofunctional (meth)acrylate oligomers having a urethane bond), polyfunctional (difunctional or higher) urethane-modified (meth)acrylate oligomers; various elastomers such as styrene copolymers; organic peroxides; polythiols; silane coupling agents such as silane compounds having a (meth)acrylic group; storage stabilizers; antioxidants; light stabilizers; rust inhibitors; solvents; pigments; dyes; flame retardants; tackifiers; and surfactants, provided that the object of the present invention is not impaired.

[0087] <Method for producing photocurable resin> The photocurable resin composition of the present invention can be produced by a conventional method. For example, the photocurable resin composition of the present invention can be obtained by weighing out predetermined amounts of component (A) and other optional components and mixing them using a mixing means such as a planetary mixer. The production conditions are not particularly limited, but it is preferable to carry out the process under light-shielded conditions to prevent the viscosity from increasing. The mixing conditions are also not particularly limited, but the mixing temperature is preferably 10 to 70°C, more preferably 20 to 50°C, and particularly preferably room temperature (25°C). The mixing time is preferably 0.1 to 5 hours, more preferably 30 to 3 hours, and particularly preferably around 60 minutes.

[0088] [Cured product] Another aspect of the present invention is a cured product (cured product of the photocurable resin composition) obtained by curing the photocurable resin composition. As will be described in detail below, the cured product is preferably obtained by curing the photocurable resin composition by irradiating it with light (for example, active energy rays such as ultraviolet light or visible light). More specifically, the cured product according to one embodiment of the present invention is preferably obtained by applying the photocurable resin composition to an adherend and then irradiating the applied photocurable resin composition with light.

[0089] <Application method> The method for applying the photocurable resin composition according to the present invention to an adherend such as a substrate is not particularly limited, and any known application method for adhesives or paints can be used, such as dispensing using an automatic coater, spraying, inkjet printing, screen printing, gravure printing, dipping, spin coating, or the like.

[0090] The thickness of the coating is not particularly limited, but is preferably adjusted so that the film thickness after drying is 0.1 to 5 mm, more preferably 0.5 to 3 mm.

[0091] <Curing method> The photocurable resin composition according to the present invention can be cured by irradiation with light (for example, active energy rays such as ultraviolet light or visible light). The term "light" as used herein refers to light in a broad sense, including various active energy rays such as radiation such as α-rays and β-rays, electromagnetic waves such as γ-rays and X-rays, electron beams (EB), ultraviolet rays with a wavelength of about 100 to 400 nm, and visible light with a wavelength of about 400 to 800 nm.

[0092] The light source used when curing the photocurable resin composition is not particularly limited, and examples thereof include low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, black light lamps, microwave-excited mercury lamps, metal halide lamps, sodium lamps, halogen lamps, xenon lamps, LEDs, fluorescent lamps, sunlight, and electron beam irradiation devices. Furthermore, as a device for curing the photocurable resin composition according to the present invention by light irradiation (active energy ray irradiation), an irradiation device having the above-mentioned light source (high-pressure mercury lamp, LED, etc.) can be used. Specific examples of such devices include, but are not limited to, a belt conveyor-type irradiator and a spot irradiator. Furthermore, the lower limit of the cumulative light dose is not particularly limited, but is preferably 0.5 kJ / m. 2 It is preferable that the concentration is 1.0 kJ / m or more. 2 Thus, the photocurable resin composition according to the present invention can be sufficiently cured even with a small cumulative light dose, and the properties of the resulting cured product are also excellent. There is no particular upper limit to the cumulative light dose, but it is preferably 50 kJ / m or more. 2 It is preferably less than or equal to 30 kJ / m 2 The following is the result.

[0093] The reaction force of the cured product according to the present invention when compressed is 1 to 300 kPa when compressed by 10%, and 1 to 500 kPa when compressed by 50%. In this specification, "reaction force when compressed by 10%" refers to the reaction force when the cured product is compressed to a thickness that is 90% of its original thickness. Similarly, "reaction force when compressed by 50%" refers to the reaction force when the cured product is compressed to a thickness that is 50% of its original thickness. The reaction force is measured specifically according to the method described in the section below under "Reaction Force of Cured Product When Compressed."

[0094] Furthermore, the cured product of the photocurable resin composition according to the present invention has the advantage that the generated repulsive force is small, particularly when compressed at a high compression ratio. Specifically, the repulsive force at 10% compression is preferably 2 to 250 kPa, more preferably 2 to 100 kPa, particularly preferably 2 to 50 kPa, and most preferably 2 to 10 kPa. Furthermore, the repulsive force at 50% compression is preferably 2 to 400 kPa, more preferably 50 to 400 kPa, particularly preferably 110 to 400 kPa, and most preferably 120 to 380 kPa. Furthermore, it is preferable that the repulsive force at 10% compression and the repulsive force at 50% compression are both within any combination of the above ranges.

[0095] (Preferred composition of photocurable resin composition) In order to obtain a cured product that generates the above-mentioned reaction force, the photocurable resin composition according to the present invention preferably has the following composition.

[0096] That is, the photocurable resin composition according to the present invention is a photocurable resin composition that does not contain a monofunctional (meth)acrylic monomer having a hydroxyl group and contains a hollow organic resin filler as component (A), and preferably further contains the above-mentioned components (B) to (E). In this case, the above-mentioned components (B), (C), and (E) are preferably compounds each containing a polyether skeleton. The polyether skeletons contained in components (B), (C), and (E) may all be the same or different. Furthermore, the preferred contents of the above-mentioned components (A) to (E) in the above embodiment can be determined by referring to the content ranges described in the sections describing each component, and the preferred ranges can be selected and combined.

[0097] Furthermore, in order to obtain a cured product that generates the aforementioned reaction force, the photocurable resin composition according to the present invention is a photocurable resin composition that does not contain a monofunctional (meth)acrylic monomer having a hydroxyl group and contains a hollow organic resin filler as component (A), and preferably further contains the above-mentioned components (B) to (F). In this case, the above-mentioned components (B), (C), and (F) preferably contain an acryloyl group. This configuration provides better photocurability of the resin composition and a smaller compression set of the resulting cured product than when one or more of the components (B), (C), and (F) contain a compound having a methacryloyl group. Furthermore, the preferred contents of the above-mentioned components (A) to (F) in the above embodiment can be determined by referring to the content ranges described in the sections describing each component, and the preferred ranges can be selected and combined.

[0098] Furthermore, in order to obtain a cured product that generates the aforementioned reaction force, the photocurable resin composition according to the present invention preferably does not contain a monofunctional (meth)acrylic monomer having a hydroxyl group and consists of the above components (A) to (G). Note that "consisting of the above components (A) to (G)" means "consisting essentially only of the above components (A) to (G)," and the inclusion of 1% by mass or less of impurities is acceptable. Furthermore, the preferred content of the above components (A) to (G) in the above embodiment can be determined by referring to the content ranges described in the sections describing each component, and the preferred ranges can be selected and combined.

[0099] Furthermore, in order to obtain a cured product that generates the above-mentioned reaction force, the photocurable resin composition according to the present invention does not contain a monofunctional (meth)acrylic monomer having a hydroxyl group, and preferably contains a hollow organic resin filler as component (A), and the content of the compound having a hydroxyl group is less than 7.6 parts by mass per 100 parts by mass of the total mass of the photocurable resin composition.

[0100] <Reaction force when cured product is compressed> In this specification, the reaction force of the cured product is measured by the following procedure.

[0101] The photocurable resin composition was sandwiched between two polyethylene terephthalate films for release, and a spacer with a thickness of 1 mm was used to form a film. Next, an ultraviolet irradiation device was used to irradiate the film with an integrated light dose of 15 kJ / m. 2 The photocurable resin composition between the films was cured by irradiating the film with ultraviolet light (wavelength 365 nm) until the peeling polyethylene terephthalate film was removed (i.e., the cured product). A sample (a 1 mm thick, 35 mm diameter disk) was prepared from the cured product. Next, using a tension compression device (Shimadzu Corporation; model number AGX-50kNV) in a 25°C atmosphere, the sample was compressed at a test compression rate of 50 mm / min to 10% (i.e., the sample was compressed to a thickness of 0.9 mm) or 50% (i.e., the sample was compressed to a thickness of 0.5 mm) of the 1 mm thickness. The stress (unit: kPa) applied from the test piece (sample) to the sensor was measured as the reaction force. The reaction force of the cured sample was measured in accordance with JIS K 7181:2011.

[0102] In the present invention, the reaction force of the cured product when compressed by 10% is preferably 1 to 300 kPa, more preferably 2 to 250 kPa. Furthermore, the reaction force of the cured product when compressed by 50% is preferably 1 to 500 kPa, more preferably 2 to 400 kPa. When the reaction force is within the above range, the reaction force generated in the cured product is small, and therefore, when a cured product of the photocurable resin composition according to the present invention is sandwiched between batteries as a cushioning material, deformation of the surface of the battery pack case can be effectively suppressed.

[0103] [Laminate] Another aspect of the present invention is a laminate formed by laminating using the photocurable resin composition. Specifically, a laminate according to one aspect of the present invention is a laminate including a first adherend, a second adherend, and the cured product, and having a configuration in which the first adherend and the second adherend are bonded together via the cured product. That is, a laminate according to one aspect of the present invention is a laminate formed by laminating a first adherend, a cured product of the photocurable resin composition, and a second adherend in this order.

[0104] There are no particular limitations on the materials that make up the first adherend and the second adherend, and for example, materials used in the fields described in the section below under [Applications] are applicable.

[0105] The method for producing the laminate is not particularly limited, but an example thereof includes a method in which the photocurable resin composition of the present invention is applied to a first adherend, a second adherend is then placed on the applied resin composition, and the applied resin composition is then irradiated with light.

[0106] [Application] The photocurable resin composition according to the present invention can be used in a variety of fields, including the automotive field, the electrical and electronic parts field, the aerospace field, etc. Among these, since a cured product having low repulsion force can be obtained over a wide range of compression ratios (compression range), particularly preferred applications include a resin for bonding a display unit and a protective panel of a liquid crystal display, and an elastic curable resin for adjusting the surface pressure applied in the stacking direction between cells when stacking cells of a fuel cell or sensor, or secondary battery (see, for example, JP 2009-158381 A).

[0107] Although the embodiments of the present invention have been described in detail, it is clear that this is by way of illustration and example only and not of limitation, and that the scope of the present invention should be interpreted by the appended claims.

[0108] The present invention encompasses the following aspects and embodiments.

[0109] [1] The cured product has a reaction force of 1 to 300 kPa when compressed by 10% and a reaction force of 1 to 500 kPa when compressed by 50%. The component (A) contains a hollow organic resin filler but does not contain a monofunctional (meth)acrylic monomer having a hydroxyl group.

[0110] [2] The photocurable resin composition according to [1], further comprising the following components (B) to (D): (B) Component: Monofunctional urethane (meth)acrylate Component (C): a monofunctional (meth)acrylic monomer other than the component (B) Component (D): Photoradical polymerization initiator.

[0111] [3] The photocurable resin composition according to [2], comprising 3 to 70 parts by mass of the component (A) per 100 parts by mass of the total of the components (B) and (C).

[0112] [4] The photocurable resin composition according to [2] or [3], wherein the weight average molecular weight of the component (B) is from 1,000 to 300,000.

[0113] [5] The photocurable resin composition according to any one of [1] to [4], further comprising a plasticizer having no (meth)acryloyl group as the component (E).

[0114] [6] The photocurable resin composition according to [5], wherein the component (B), the component (C), and the component (E) are each a compound containing a polyether skeleton.

[0115] [7] The photocurable resin composition according to any one of [1] to [6], wherein the average particle size of the component (A) is 5 to 300 μm.

[0116] [8] The photocurable resin composition according to any one of [1] to [7], wherein the organic resin of the component (A) comprises an acrylonitrile-methacrylonitrile-methyl methacrylate copolymer.

[0117] [9] The photocurable resin composition according to any one of [1] to [8], further comprising a di- or higher functional (meth)acrylic monomer as a component (F).

[0118]

[10] A cured product of the photocurable resin composition according to any one of [1] to [9].

[0119]

[11] A laminate comprising a first adherend, a second adherend, and the cured product according to

[10] , wherein the first adherend and the second adherend are bonded together via the cured product.

[0120] The present invention also includes the following aspects.

[0121] [1'] A photocurable resin composition that does not contain a monofunctional (meth)acrylic monomer having a hydroxyl group and contains a hollow organic resin filler as component (A), wherein a cured product of the photocurable resin composition has a reaction force of 1 to 300 kPa when compressed by 10% and a reaction force of 1 to 500 kPa when compressed by 50%.

[0122] Furthermore, the present invention may take the above-mentioned embodiments [2] to

[11] in the above-mentioned embodiment [1']. [Example]

[0123] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, operations and tests were carried out in an environment of 25°C and 55% RH.

[0124] <Preparation of Photocurable Resin Composition> Example 1 The following components (A) to (G) were weighed and mixed for 60 minutes using a mixer at 25°C in a light-shielded environment to obtain a photocurable resin composition that was liquid at 25°C (Example 1); As component (A), component (a1): average particle size 80 μm, true specific gravity 0.13 g / cm 3 20 parts by mass of hollow filler (microsphere) made of acrylonitrile-methacrylonitrile-methyl methacrylate copolymer with calcium carbonate attached to the surface (manufactured by Nippon Phillite Co., Ltd.; EMC-80B) As the component (B), (b1): 80 parts by mass of a monofunctional polyether-based urethane acrylate (manufactured by Negami Chemical Industrial Co., Ltd.) having a weight-average molecular weight of 30,000 As the component (C), (c1): 35 parts by mass of ethoxydiethylene glycol monoacrylate (Miramer (registered trademark) M170, molecular weight 188, manufactured by Toyo Chemicals Co., Ltd.) As the component (D), (d1): 3 parts by mass of 2-hydroxy-2-methyl-1-phenyl-propan-1-one (manufactured by DOUBLE BOND CHEMICAL IND. CO., LTD.; Double Cure (registered trademark) 173) As the component (E), (e1): 44 parts by mass of polypropylene glycol (manufactured by NOF Corporation; Uniol (registered trademark) D2000) having a number average molecular weight of 2000 and a repeating number of alkylene oxide of 34 As the component (F), (f1): 1.6 parts by mass of dipentaerythritol hexaacrylate (manufactured by Daicel Allnex Corporation; DPHA; molecular weight 579) As the component (G), component (g1): 7 parts by mass of silica particles (fumed silica) surface-treated with dimethyl silicone.

[0125] Example 2 A photocurable resin composition that was liquid at 25°C (Example 2) was obtained in the same manner as in Example 1, except that the content of component (a1) was changed from 20 parts by mass to 25 parts by mass.

[0126] Example 3 In Example 2, component (a1) was replaced with component (a2): average particle size 120 μm, true specific gravity 0.10 g / cm 3 A photocurable resin composition that was liquid at 25°C was prepared in the same manner as in Example 2, except that hollow fillers (microspheres) made of acrylonitrile-methacrylonitrile-methyl methacrylate copolymer (manufactured by Nippon Fillite Co., Ltd.; 120α) with calcium carbonate attached to the surface were added, to obtain a photocurable resin composition (Example 3) that was liquid at 25°C.

[0127] Example 4 In Example 3, the 80 parts by mass of component (b1) was replaced with 70 parts by mass of component (b2): a monofunctional polyether-based urethane acrylate (manufactured by Negami Chemical Industrial Co., Ltd.) having a weight-average molecular weight of 20,000, and the content of component (e1) was changed from 44 parts by mass to 60 parts by mass. Except for this, a photocurable resin composition that was liquid at 25°C was obtained in the same manner as in Example 3 (Example 4).

[0128] Example 5 A photocurable resin composition that was liquid at 25°C (Example 5) was obtained in the same manner as in Example 4, except that the content of component (f1) was changed from 1.6 parts by mass to 3.2 parts by mass.

[0129] Comparison Example 1 A photocurable resin composition that was liquid at 25° C. was obtained in the same manner as in Example 1, except that the component (a1) was not added (Comparative Example 1).

[0130] Comparison Example 2 In Example 1, component (a1) was replaced with component (a'1): average particle size 65 μm, true specific gravity 0.13 g / cm 3 A photocurable resin composition that was liquid at 25°C was obtained in the same manner as in Example 1, except that the glass hollow filler (manufactured by 3M; Glass Bubbles K1) was used instead (Comparative Example 2).

[0131] Comparative Example 3 A photocurable resin composition that is liquid at 25°C (Comparative Example 3) was obtained in the same manner as in Example 4, except that the component (c1) in Example 4 was changed to 2-hydroxyethyl acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd.) (c'1).

[0132] Comparative Example 4 In Example 4, the content of the (c1) component was changed from 35 parts by mass to 15 parts by mass, and further, the content of the (c'1) component was changed to 15 parts by mass. In the same manner as in Example 4, a photocurable resin composition that was liquid at 25°C was obtained (Comparative Example 4).

[0133] The components and amounts contained in the photocurable resin compositions of the Examples and Comparative Examples are shown in Table 1. Note that blank spaces indicate that the corresponding component was not added.

[0134] The photocurable resin compositions according to the above-mentioned Examples and Comparative Examples were subjected to the following tests (1) and (2). The test methods for tests (1) and (2) are as follows.

[0135] <Test (1): Reaction force when cured product is compressed> Each photocurable resin composition was sandwiched between two polyethylene terephthalate release films and formed into a film using a spacer with a thickness of 1 mm. Next, an ultraviolet irradiation device was used to irradiate the film with an integrated light dose of 15 kJ / m. 2 The photocurable resin composition between the films was cured by irradiating the film with ultraviolet light (wavelength 365 nm) until the film thickness reached 0.9 mm. The polyethylene terephthalate peeling film was then removed (i.e., the cured product). A 1 mm thick, 35 mm diameter disk was cut from the cured product and used as a sample. Next, using a compression device (Shimadzu Corporation; Model No. AGX-50kNV) in a 25°C atmosphere at a compression rate of 50 mm / min, the reaction force (unit: kPa) applied to the sensor was measured when the sample was compressed by 10% (i.e., the sample was compressed to a thickness of 0.9 mm) or 50% (i.e., the sample was compressed to a thickness of 0.5 mm) of the 1 mm thickness. The reaction force of the cured product of each sample was measured in accordance with JIS K 7181:2011. The results are shown in Table 1. Note that "uncured" in the table means that the sample remained liquid even after irradiation with ultraviolet light.

[0136] <Test (2): Photocuring test> 0.01 g of each photocurable resin composition was dropped onto a glass test piece measuring 25 mm wide, 100 mm long, and 5 mm thick. Then, the test piece was placed in an ultraviolet irradiator (conveyor UV irradiator; light source: LED; UV wavelength: 365 nm; peak irradiance: 650 mW / cm). 2 ) with an integrated light output of 1.5kJ / m 2 The test pieces were then contacted with a sharpened glass rod, and the curability of each photocurable resin composition was evaluated based on the following criteria: [Evaluation criteria] ○: No adhesions on the rod ×: There is something attached to the rod.

[0137] [Table 1]

[0138] As shown in Table 1, it was confirmed that the photocurable resin compositions of Examples 1 to 5 rapidly yield cured products by photocuring, and that cured products with low repulsion force were obtained over a wide range of compression ratios (compression ranges).

[0139] On the other hand, Comparative Example 1 is a photocurable resin composition that does not contain the component (A) of the present invention, but the reaction force of the cured product when compressed by 50% was too high. Comparative Example 2 is a photocurable resin composition that contains the component (a'1), a hollow glass filler, instead of the component (A) of the present invention, but the reaction force of the cured product when compressed by 50% was too high. Furthermore, Comparative Examples 3 and 4 are photocurable resin compositions that contain the component (c'1), a monofunctional acrylic monomer having a hydroxyl group, but the photocurability was significantly poor. [Industrial Applicability]

[0140] The photocurable resin composition according to the present invention provides a cured product with low repulsion over a wide range of compression ratios (compression ranges), and therefore can be used in a variety of fields and is industrially useful. Furthermore, the photocurable resin composition according to the present invention not only provides a cured product quickly upon photocuring, but is also liquid before curing, so that surface coating, screen printing, or the like can be selected to obtain the cured product, which can contribute to improved productivity.

[0141] This application is based on Japanese Patent Application No. 2020-187535, filed on November 10, 2020, the disclosure of which is incorporated by reference in its entirety.

Claims

1. A photocurable resin composition, the reaction force of which when compressed by 10% is 2 to 100 kPa and when compressed by 50% is 110 to 400 kPa, comprising the following components (A) to (E), but not containing a monofunctional (meth)acrylic monomer having a hydroxyl group: (A) Hollow organic resin filler Component (B): monofunctional urethane (meth)acrylate Component (C): a monofunctional (meth)acrylic monomer other than the component (B) Component (D): Photoradical polymerization initiator Component (E): a plasticizer that does not have a (meth)acryloyl group.

2. 2. The photocurable resin composition according to claim 1, wherein the component (A) is contained in an amount of 3 to 70 parts by mass per 100 parts by mass of the total of the component (B) and the component (C).

3. 3. The photocurable resin composition according to claim 1, wherein the weight average molecular weight of the component (B) is 1,000 to 300,000.

4. The photocurable resin composition according to any one of claims 1 to 3, wherein the component (B), the component (C), and the component (E) are each a compound containing a polyether skeleton.

5. 5. The photocurable resin composition according to claim 1, wherein the component (A) has an average particle size of 5 to 300 μm.

6. 6. The photocurable resin composition according to claim 1, wherein the organic resin of the component (A) comprises an acrylonitrile-methacrylonitrile-methyl methacrylate copolymer.

7. The photocurable resin composition according to any one of claims 1 to 6, further comprising a di- or higher functional (meth)acrylic monomer as component (F).

8. A cured product of the photocurable resin composition according to any one of claims 1 to 7.

9. 9. A laminate comprising a first adherend, a second adherend, and the cured product according to claim 8, wherein the first adherend and the second adherend are bonded together via the cured product.

Images