JP2017043699A - Active energy ray curable resin composition, seal material using the same and manufacturing method of the seal material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an active energy ray curable resin composition excellent in coatability and form accuracy, having low resilience and small in permanent compressive set after curing, and a seal material using the same.SOLUTION: There is provided an active energy ray curable resin composition containing an active energy ray curable resin (A), a polymerization initiator (B), and a silica particle (C), where the active energy ray curable resin (A) contains a (meth)acryloyl monomer (a) having an oligo glycol unit and an alkyl group, a (meth)acryloyl monomer (b) having a hydroxyl group and an alkyl (meth)acrylate monomer (c), in which percentage of the total of the component (a) and the component (b) to the active energy ray curable resin (A) is 50 wt.% or more, weight ratio of the total of the component (a) and the component (b) to the component (c) is 99:1 to 50:50, percentage of the active energy ray curable resin (A) to the active energy ray curable resin composition is 80 wt.% or more, and percentage of the silica particle (C) is 2 to 12 wt.%.SELECTED DRAWING: None

Description

  The present invention relates to an active energy ray-curable resin composition and a cured member using the same, and more specifically, it has excellent shape accuracy and productivity in discharge coating, and has a small compression set at the time of curing and an active energy excellent in low resilience. The present invention relates to a linear curable resin composition, a sealing material using the same, and a method for producing the sealing material.

  With the miniaturization of portable information terminal devices such as mobile phones and smartphones, and electronic devices such as digital cameras, component parts are becoming smaller and more integrated. For example, sealing materials (packings, gaskets, etc.) used for housings However, the line width has been shifted to a narrow design, and at present, for example, a sealing material having a width of about 1 mm is used. These components are often made of a soft material, and because of its softness, when the line width of the sealing material becomes thin or the size of the cushioning material becomes extremely small, the conventional component parts such as a fragmented sealing material As a result, it becomes difficult to incorporate the material into a housing or the like, resulting in a decrease in productivity and an increase in cost.

  As a countermeasure, a liquid sealing material such as an ultraviolet curable resin is directly applied to a portion to which a sealing material of a casing or the like (base body) is attached by spraying it from a needle in a bead shape (hereinafter referred to as “needle coating”). Then, a method of curing the bead-like discharge body with ultraviolet rays to form a sealing material and mounting it at the same time (so-called cured-in-place method: hereinafter referred to as CIP method) has been proposed (for example, Patent Documents). (See 1, 2 etc.). From the viewpoint of improving the dischargeability (coating property) of such a liquid sealing material and the shape retention of the applied bead-shaped discharge body before curing, Patent Document 1 discloses silica particles in an ultraviolet curable resin. Is disclosed, and Patent Document 2 discloses a technique in which the viscosity of the coating material is about 1 to 1000 Pa · s at the coating temperature. However, in the above methods and techniques, in order to narrow or narrow the line width of the sealing material, the smaller the diameter of the needle discharge port, the more difficult it is to discharge the liquid sealing material. If the viscosity of the liquid sealing material is lowered in an attempt to give priority to ejection properties or swell, the bead-like ejection body will sag after application and the line width of the sealing material will be widened to obtain a sealing material with a desired fine line width. There were problems and issues that made it difficult.

  On the other hand, when a sealing material is incorporated into a thinned member such as a housing, if the resilience of the sealing material is large, the housing is likely to be deformed. From the viewpoint of durability of the sealing material, it is required that the compression set is small (hereinafter sometimes referred to as low compression set). Compression set is a value that expresses how much the compression stress is restored after releasing the compression stress to a predetermined amount for a certain amount of time, and the amount of non-restoration is large. Since the sealing performance decreases with time, it is important for the sealing material that the compression set is small. That is, there is a need for an ultraviolet curable resin that has both ejection properties and shape retention in an uncured state, low resilience during curing, and low compression set. However, in order to realize dischargeability and shape retention in an uncured state, it is effective to impart thixotropy, and a method for producing a gasket obtained by curing a UV curable material containing a large amount of a compound having a relatively large molecular weight (Patent Document 1) and photocurable silicone gels for sealing materials to which thickeners such as silica particles are added (Patent Document 2) have been proposed, but have sufficient low resilience and low compression set. It was difficult to express.

  In addition, as a technique for imparting flexibility to a sealing material as a cured product, an energy ray curable resin composition for a gasket in which an acrylic compound and a thiol compound are mixed (for example, Patent Documents 3 to 4) and an acrylic monomer are used. A photocurable resin composition for gaskets (for example, Patent Documents 5 to 8) and a liquid gasket material for precision equipment that cures active energy rays using a mixture of urethane acrylate oligomer and acrylic monomer (for example, Patent Document 9) are disclosed. Yes. However, the energy ray curable elastomer composition disclosed in Patent Document 3 and the gasket material disclosed in Patent Document 4 have a large number of crosslinking points because a large amount of a crosslinking agent composed of polyfunctional thiol is added to the acrylic compound. Can't get enough softness. In addition, the photocurable resin composition for gaskets disclosed in Patent Document 5, the gasket described in Patent Document 6, and the liquid gasket material for precision instruments disclosed in Patent Document 8 use a large amount of oligomer components having a large molecular weight. However, sufficient softness could not be obtained, and even if the resin compositions disclosed in Patent Documents 7 and 8 were used, sufficient softness could not be obtained.

  Furthermore, if the cured product such as a sealing material is soft and has low resilience, compression set becomes large. Therefore, a monomer containing a hydroxyl group is used in the composition for the purpose of achieving both low hardness and low compression set. The photocurable composition (Patent Document 10) and the gasket composition (Patent Document 11) have been proposed, but the hardness has not been reduced so as to induce sufficient low resilience.

Japanese Patent Application Laid-Open No. 2004-289943 Japanese Patent Application Laid-Open No. 07-088430 JP 2010-254853 A JP 2010-260918 A JP 2004-26919 A Japanese Patent Application Laid-Open No. 2014-148643 WO2002 / 044299 JP 2014-80498 A JP 2003-105320 A WO96 / 10594 WO2012 / 073688

  The first problem to be solved by the present invention is that, in view of the above-mentioned problems of the prior art, it has fluidity and thixotropic properties suitable for the CIP method, is excellent in coating property and shape accuracy, and has low repulsion after curing. It is providing the active energy ray-curable resin composition which is excellent in the property and low compression set.

  In addition, the second object of the present invention is to have fluidity and thixotropy suitable for the CIP method, excellent coating properties and shape accuracy, and low rebound and low compression set after curing. It is providing the sealing material formed with the CIP method to which the energy-beam curable resin composition is applied.

In order to solve the above problems, the active energy ray-curable resin composition of the present invention comprises an active energy ray-curable resin (A), a polymerization initiator (B), and silica particles (C), and has an active energy. The linear curable resin (A) has the following formula (1) having an oligoglycol unit and an alkyl group in the molecule (wherein R ₁ is hydrogen or a methyl group, R ₂ is an alkyl group, W is an alkylene group, n is (Meth) acryloyl monomer (a) represented by the following formula (2) having a hydroxyl group in the molecule (wherein R ₃ is hydrogen or a methyl group, R ₄ is a methylene group) And a (meth) acryloyl monomer (b) represented by the following formula (3) (wherein R ₅ is hydrogen or a methyl group, R ₆ has 5 carbon atoms) These are the above alkyl groups.) The ratio of the total weight of the (meth) acryloyl monomer (a) and the (meth) acryloyl monomer (b) to the weight of the active energy ray-curable resin (A) comprising the rualkyl (meth) acrylate monomer (c) is The ratio of the total weight of the (meth) acryloyl monomer (a) and the (meth) acryloyl monomer (b) to the weight of the alkyl (meth) acrylate monomer (c) {(a) + (b) }: (C) is 99: 1 to 50:50, and the weight ratio of the active energy ray-curable resin (A) in the active energy ray-curable resin composition is 80% by weight or more. The weight ratio of the silica particles (C) in the conductive resin composition is 2 to 12% by weight.

  Moreover, it is also preferable that weight ratio (a) :( b) of (meth) acryloyl monomer (a) and (meth) acryloyl monomer (b) is 99: 1 to 70:30.

  Moreover, (meth) acryloyl monomer (a) consists of (meth) acryloyl monomer (a1) whose n in Formula 1 is 1-5, and (meth) acryloyl monomer (a2) whose n is 6-20. It is also preferred that the weight ratio of the (meth) acryloyl monomer (a2) to the (meth) acryloyl monomer (a) is 1% by weight or more and less than 90% by weight.

  Moreover, it is also preferable that the active energy ray-curable resin (A) contains less than 20% by weight of urethane (meth) acrylate having a weight average molecular weight of 6000 or more.

And the active energy ray hardening composition of each embodiment of this invention WHEREIN: In the range of the shear rate 0.1-2 s < ^-1 > in an unhardened state, the viscosity (JIS-Z8803-compliant cone-plate type rotational viscometer 25 ° C) is 10 to 4000 Pa · s, and the thixotropic coefficient is 1.1 to 10, E hardness after active energy ray curing (according to JIS K6253) is 55 or less, and compression set (according to JIS K6262 is 70 ° C). 25% compression) is preferably 35% or less.

  The active energy ray-curable composition of each embodiment of the present invention is discharged and applied to a substrate surface in a bead shape or a dot shape to form a discharge body, and the discharge body is irradiated with active energy rays and cured. Thus, the sealing material of the present invention is obtained.

  The active energy ray-curable resin composition of the present invention is excellent in ejectability during needle application, is less likely to cause a bead-like ejector to expand in diameter (Swell), has a high ejection shape accuracy of the bead-like ejector, and Since the shape retaining property of the bead-shaped discharge body after application is excellent, a sealing material with high shape accuracy can be formed with high productivity. The active energy ray-curable resin composition of the present invention is specifically suitable for forming a bead-shaped sealing material to be applied with a needle using an ultrafine needle having an inner diameter of 1 mmφ or less. The above-described effect is remarkably exhibited when a needle having an even smaller diameter having an inner diameter of 0.75 mmφ or less is used. The active energy ray-curable resin composition can be instantly cured by irradiation with active energy rays, and the cured product has a low hardness, a small compression set, and a sealing material excellent in airtightness and durability. Contributes to downsizing and cost reduction of electronic equipment.

It is a schematic diagram which shows the example of the coating apparatus which discharges the active energy ray curable resin composition of this invention to bead shape, forms a bead-like discharge body, and makes active energy ray hardening. It is a schematic diagram which shows the application pattern of the test bead-shaped discharge body in an Example.

  The active energy ray-curable resin composition of the present invention (hereinafter sometimes simply referred to as a resin composition or a curable resin composition) includes an active energy ray-curable resin (A), a polymerization initiator (B), and The active energy ray-curable resin (A) comprises silica particles (C), and the (meth) acryloyl monomer (a) represented by the above formula (1) having an oligoglycol unit and an alkyl group in the molecule. And at least the (meth) acryloyl monomer (b) represented by the above formula (2) having a hydroxyl group in the molecule and the alkyl (meth) acryloyl monomer (c) represented by the above formula (3), The proportion of the total weight of the (meth) acryloyl monomer (a) and the (meth) acryloyl monomer (b) in the weight of the active energy ray-curable resin (A) is 50% by weight or more. The ratio of the total weight of (meth) acryloyl monomer (a) and (meth) acryloyl monomer (b) to the weight of alkyl (meth) acrylate monomer (c) {(a) + (b)}: (c) 99: 1 to 50:50, and the weight ratio of the active energy ray curable resin (A) in the active energy ray curable resin composition is 80% by weight or more, and occupies the active energy ray curable resin composition. The weight ratio of the silica particles (C) is 2 to 12% by weight. Hereinafter, each item will be described.

1. Composition of active energy ray-curable resin composition
1-1. Active energy ray curable resin (A)
The active energy ray-curable resin (A) used in the active energy ray-curable resin composition of the present invention is a component that cures by an active energy ray in the presence of the polymerization initiator (B). The following formula (1) having an oligoglycol unit and an alkyl group in the molecule (wherein R ₁ is hydrogen or a methyl group, R ₂ is an alkyl group, W is an alkylene group, and n is an integer of 1 to 20). And the following formula (2) having a hydroxyl group in the molecule (wherein R ₃ is a hydrogen or methyl group, R ₄ is a functional group having a molecular weight of 110 or less including a methylene group) A (meth) acryloyl monomer (b) represented by formula (3) and the above formula (3) (wherein R ₅ is hydrogen or a methyl group, and R ₆ is an alkyl group having 5 or more carbon atoms). Alkyl (meta A resin component containing acrylate monomer (c).

  Here, the active energy rays refer to infrared rays, visible rays, ultraviolet rays, X-rays, electron beams, alpha rays, beta rays, gamma rays, and the like, and ultraviolet rays are particularly preferably used. The ultraviolet rays in the present invention include near ultraviolet rays (near UV, wavelength 200 to 380 nm), far ultraviolet rays (wavelength 10 to 200 nm), and extreme ultraviolet rays (extreme UV, wavelength 1 to 10 nm). These active energy rays can be used alone or in combination of two or more. The source of these active energy rays is not particularly limited as long as the purpose of curing in a short time after coating or coating the resin composition on the substrate to be coated, but as a source of ultraviolet rays. For example, a known generation means such as a low-pressure mercury lamp, a high-pressure mercury lamp, an excimer ultraviolet (excimer UV) lamp, a halide lamp, an LED light, or a laser can be used. Examples of the infrared ray source include a lamp, a resistance heating plate, or a laser. Examples of the visible ray source include direct sunlight, a lamp, a fluorescent lamp, an LED light, and a laser. As an electron beam source, for example, a system using a thermoelectron generated from a commercially available tungsten filament, a cold cathode system that generates a metal through a high voltage pulse, and an ionized gaseous molecule and a metal electrode Examples include secondary electron type devices that utilize secondary electrons generated by collision. Furthermore, as a source of alpha rays, beta rays, and gamma rays, for example, a fission material such as Co60 can be cited. For gamma rays, a vacuum tube that collides accelerated electrons with the anode can be used. These active energy rays may be irradiated alone or in combination of two or more.

1-1a. (Meth) acryloyl monomer (a)
The (meth) acryloyl monomer (a) having an oligoglycol unit and an alkyl group in the molecule is represented by the above formula 1 having a (meth) acryloyl group that can be polymerized by irradiation with active energy rays at one position in the molecule. It is a compound having a structure, and is an important compound for achieving both low hardness and low compression set. In the above formula 1, R ₁ is hydrogen or a methyl group, R ₂ is an alkyl group, W is an alkylene group, and n is an integer of 1 to 20. When n is 21 or more, the physical properties of the cured product deteriorate, such as low hardness and low rebound characteristics at low temperatures, or increased compression set. The (meth) acryloyl monomer (a) includes a (meth) acryloyl monomer (a1) in which n in the above formula 1 is 1 to 5 or less, and a (meth) acryloyl monomer (a2) in which n is 6 to 20 or less. It is preferable that the content of the (meth) acryloyl monomer (a2) contained in the (meth) acryloyl monomer (a) is 1% by weight or more and less than 90% by weight. If the content of the (meth) acryloyl monomer (a2) is less than 1% by weight, the E hardness of the cured product of the active energy ray-curable resin composition may increase, and if it is 90% by weight or more, the cured product. Therefore, the content of the (meth) acryloyl monomer (a2) is preferably in the above range.

  Specific examples of the (meth) acryloyl monomer (a1) in the (meth) acryloyl monomer (a) include butoxyethyl acrylate, ethoxydiethylene glycol acrylate, methoxydipropylene glycol acrylate, methoxytriethylene glycol acrylate, methoxytetraethylene glycol acrylate, methoxy Examples include pentaethylene glycol acrylate and methacrylates of the aforementioned compounds.

  Specific examples of the (meth) acryloyl monomer (a2) include light acrylate (registered trademark) 130A, light ester 130MA (manufactured by Kyoeisha Chemical Co., Ltd.), AM-130G, S-12E, and S-20E (new, new). Nakamura Chemical Co., Ltd.).

1-1b. (Meth) acryloyl monomer (b)
The (meth) acryloyl monomer (b) having a hydroxyl group in the molecule contributes to the reduction of compression set together with the (meth) acryloyl monomer (a), and is a component represented by the above formula 2. R ₄ in the above formula 2 is a functional group having a molecular weight of 110 or less including a methylene group. When this R ₄ does not contain a methylene group (that is, when R ₄ is hydrogen), sufficient curing does not occur after irradiation with active energy rays, the compression set becomes large, stickiness remains on the surface, etc. Physical properties preferable as a sealing material cannot be obtained. _{On the} other hand, if the molecular weight of R ₄ is 111 or more, the compression set is increased or the E hardness is increased.

  Specific examples of the (meth) acryloyl monomer (b) include 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, 2-hydroxypentyl acrylate, 2-hydroxyhexyl acrylate, 2-hydroxyheptyl acrylate, 2-hydroxy-3- Examples include phenoxypropyl acrylate, 3-butoxy-2-hydroxypropyl acrylate, and methacrylates of the aforementioned compounds.

  The ratio of the total weight of the (meth) acryloyl monomer (a) and the (meth) acryloyl monomer (b) to the weight of the active energy ray-curable resin (A) is 50% by weight or more, more preferably 70% by weight. It is above, More preferably, it is 80 weight% or more. When this ratio is less than 50% by weight, it is difficult to achieve both low hardness and low compression set.

  The (meth) acryloyl monomer (a) and the (meth) acryloyl monomer (b) preferably have a composition ratio in a range where the weight ratio (a) :( b) is 99: 1 to 70:30. . When the constituent ratio of the (meth) acryloyl monomer (b) is less than the above-described value, the action of reducing the compression set may be small, and when it is larger than the above constituent ratio, the action of reducing the E hardness may be small. Therefore, it is preferable to set it as the said composition ratio.

1-1c. Alkyl (meth) acrylate monomer (c)
Moreover, it is also preferable that the active energy ray-curable resin (A) of the present invention further includes an alkyl (meth) acrylate monomer (c) having the structure of the above formula 3. The alkyl (meth) acrylate monomer (c) is a compound composed of alkyl groups represented by (meth) acrylic ester moiety and R _6, the number of carbon atoms in the alkyl group (R ₆₎ is located at least 5 5-17 are preferable, and 6-14 are more preferable. When the carbon number of the alkyl group is 4 or less, the compression set becomes large, or it is volatile due to the heat generated during irradiation with active energy rays and affects the use environment as an outgas. In addition, when the carbon number of the alkyl group is 18 or more, the cured product after irradiation with active energy rays has increased hardness and no low resilience is exhibited, or the compression set has increased physical properties of the cured product. In some cases, the carbon number is 5 to 17 as described above.

  The blending ratio of the alkyl (meth) acrylate monomer (c) is the weight ratio {(a) + (b)} to the total weight of the (meth) acryloyl monomer (a) and the (meth) acryloyl monomer (b): (c) However, it is preferable that it exists in the range of 99: 1-50: 50. When the blending ratio of the alkyl (meth) acrylate monomer (c) is less than the above range, the E hardness after curing may increase, and the blending ratio of the alkyl (meth) acrylate monomer (c) is larger than the above range. The above range is preferable because the compression set after curing may increase.

  Specific examples of the alkyl (meth) acrylate monomer (c) include pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, and nonyl (meth). ) Acrylate, decyl (meth) acrylate, undecyl (meth) acrylate, lauryl (meth) acrylate, myristyl (meth) acrylate, cetyl (meth) acrylate.

  The other component contained in the active energy ray-curable resin (A) can be applied without particular limitation as long as it is a compound having a (meth) acryloyl group and a functional group polymerizable in the molecule. Specifically, vinyl ether compounds, thiol compounds, urethane (meth) acrylates, polyester (meth) acrylates and the like can be preferably applied, but from the viewpoint of imparting low resilience due to curability after irradiation with active energy rays and low hardness, Urethane (meth) acrylate is preferable, its weight average molecular weight is 6000 or more, and the number of functional groups contained in one molecule is more preferably in the range of 1 to 4. The proportion of urethane (meth) acrylate contained in the active energy ray curable resin (A) is less than 20% by weight, preferably 15% by weight or less, more preferably 10% by weight or less. When the content of urethane (meth) acrylate exceeds 20% by weight, the E hardness of the cured product increases and the low resilience may be impaired, so the above range is preferable. Specific examples of urethane (meth) acrylates include the purple light (registered trademark) series (for example, UV-2000B, UV-3000B, UV-3200B, UV-3210EA, UV-3300B, UV-made by Nippon Synthetic Chemical Industry Co., Ltd.). 3500BA, UV-3520TL, UV-3700B, etc.), Art Resin (registered trademark) series (for example, UN-5590, UN-6202, UN-6301, KHP-22, TFX-1N, etc.) manufactured by Negami Kogyo Co., Ltd. It is done.

  Further, from the viewpoint of achieving both low hardness and low compression set, a compound containing at least one (meth) acryloyl group in the molecule and having one or two functional groups polymerizable by irradiation with active energy rays It is also preferable to include a glycol ester of (meth) acrylate which is

  The active energy ray-curable resin (A) is blended so as to be 80% by weight or more of the entire active energy ray-curable resin composition. When the blending ratio of the active energy ray curable resin (A) is less than 80% by weight, it is suitable because the compression set cannot be reduced or the uncured material oozes out when used as a sealing material. Absent.

1-2. Polymerization initiator (B)
The polymerization initiator (B) used in the active energy ray-curable resin composition of the present invention is a compound that can cure the active energy ray-curable resin (A) by being irradiated with active energy rays. Although not particularly limited, a compound generally called a photoradical generator is preferably used. The preferable content of the polymerization initiator (B) is 0.01 to 6% by weight, more preferably 0.1 to 3% by weight, based on the active energy ray-curable resin (A). When the content of the polymerization initiator (B) is less than 0.01% by weight, it is not preferable because sufficient curing is not performed after the active energy ray irradiation, and the content of the polymerization initiator (B) is 6% by weight. When it exceeds, the amount of polymerizable active energy ray-curable resin (A) becomes relatively small, the cured product becomes brittle, or excess polymerization initiator (B) becomes active energy ray-curable. The above-mentioned range is preferable because it may ooze out from the surface of the resin composition and cause problems. Specific examples of the polymerization initiator (B) include Irgacure 184, Irgacure 500, Irgacure 754, Irgacure 369, Irgacure 907, Irgacure 819, Darocur 1173, Darocur MBF, Darocur TPO (Irgacure, Darocur are registered trademarks) of BASF Japan. Are well known, and may be used alone or in combination.

1-3. Silica particles (C)
The silica particles (C) used in the active energy ray-curable resin composition of the present invention are components that impart thixotropic properties to the uncured active energy ray-curable resin composition and function as a thixotropic agent. To do. Since the active energy ray-curable resin composition in which the silica particles (C) are uniformly dispersed has a gentle stitch structure in which a plurality of silica particles (C) are formed in a low shear rate region. The apparent viscosity is high, and in the high shear rate region, the stitch structure is destroyed by the shearing force and exhibits a thixotropic property that lowers the viscosity. By imparting this thixotropic property, it has excellent fluidity (dischargeability) when a small-diameter needle is applied (high shear rate state) in the CIP method, and has a high viscosity in the natural state (low shear rate state) after discharge. Thus, the shape of the discharged material is maintained.
Examples of such thixotropy-imparting agents include long-chain fatty acid ester polymers, amide waxes, polyethylene oxide waxes, sulfate anion activators, polycarboxylic acids, polycarboxylic acid amine salts, organic compounds such as polyethers, and calcium carbonate. Inorganic fine particles such as heavy calcium carbonate, bentonite and sepiolite, resin fine particles such as Teflon (registered trademark) and silicone can be preferably used, but from the viewpoint of balance between fluidity and thixotropic properties, Silica fine particles are applied.

  As the silica particles (C), fumed silica fine particles are preferable, and fumed silica particles subjected to hydrophobic treatment are more preferable. Hydrophobic treatment means treatment for coating the surface of silica particles formed by siloxane bonds with an organic compound or a (poly) dimethylsiloxane compound. In addition, when hydrophobicity is imparted by coating with an organic compound, the degree of hydrophobicity corresponds to the amount of organic matter on the surface of the silica particles (C), that is, the amount of carbon. The carbon content in the particles (C) is preferably 0.5% by weight or more, more preferably 1.0% by weight or more, and further preferably 2.0% by weight or more. Specific examples of the silica particles (C) include Aerosil (registered trademark) series (for example, 150, 200, 300, R974, R976, RX200, RX300, RY200, R711, NX90G, etc.) manufactured by Nippon Aerosil Co., Ltd., Asahi Kasei Wacker Silicone WACKER HDK (registered trademark) series (for example, S13, V15, N20, N20P, T30, T40, etc.) manufactured by the company can be mentioned.

  The amount of silica particles (C) added is preferably 2 to 12% by weight, more preferably 4 to 12% by weight, based on the entire active energy ray-curable resin composition. When the addition amount of silica particles is less than 2% by weight, good thixotropic properties cannot be obtained, and when it exceeds 12% by weight, at least one of E hardness and compression set of the cured product is increased and the effect of the present invention is obtained. Therefore, the above-mentioned blending range is set.

2. Physical Properties of Active Energy Ray Curable Resin Composition The active energy ray curable resin composition of the present invention has the effect of the present invention that the bead-like ejected substance is less likely to undergo swell and the shape retention after application is high. In order to exert an effect, the viscosity at the time of uncuring is 10 to 4000 Pa · s (cone JIS Z8803 compliant cone-plate rotational viscometer in the shear rate range of 0.1 to 2 s ⁻¹ , based on the above-described composition. 25 ° C.) and the thixotropy coefficient is preferably adjusted to 1.1 to 10.

First, the viscosity will be described in detail. Since the active energy ray-curable resin composition of the present invention is blended with a thixotropy imparting agent to exhibit thixotropy and exhibit non-Newtonian fluid properties, the viscosity in the present invention is an apparent viscosity, which will be described as an apparent viscosity hereinafter. To do.
The apparent viscosity of the active energy ray-curable resin composition of the present invention in the uncured state (hereinafter sometimes simply referred to as apparent viscosity) is “viscosity measured by a cone-plate rotational viscometer” in JIS Z8803 (1991). According to the “Measurement Method”, it is a value measured in a range of a shear rate of 0.1 to 2 s ⁻¹ under 25 ° C., and specifically, a value at a shear rate of 1.0 s ⁻¹ is preferable. The uncured state is a state where the active energy ray-curable resin composition is not irradiated with an active energy ray for curing. The apparent viscosity of the active energy ray-curable resin composition of the present invention is preferably 10 to 4000 Pa · s, more preferably 20 to 3000 Pa · s, still more preferably 30 to 3000 Pa · s, and particularly preferably 40 to 800 Pa · s. . If the apparent viscosity is less than 10 Pa · s, it will flow too much after being ejected from a needle or the like, resulting in poor shape retention, and if it exceeds 4000 Pa · s, it will be difficult to eject from the needle or the like, and the tensile stress during application will be The above range is preferable because it may be easily cut or diametrical expansion may occur.

1.1-10 are preferable, as for the thixotropy coefficient (henceforth only called a thixotropy coefficient) of the active energy ray curable resin composition of this invention, 2-9 are more preferable, and 2.5-8 are. Further preferred. If the thixotropy coefficient is less than 1.1, it will flow too much after being discharged from a needle or the like, resulting in a decrease in shape retention, and if it exceeds 10, the dischargeability from the needle or the like will be reduced, resulting in tensile stress at the time of application. In some cases, the bead-shaped discharge body is likely to be cut or the diameter is likely to be expanded. Therefore, the above range is preferable. Here, the thixotropy coefficient (TI) is the apparent viscosity η (D ₁ ) at the shear rate D ₁ measured with a cone-plate rotational viscometer (25 ° C.) according to JIS Z8803, and the shear rate D _2. since the apparent viscosity eta _{(D 2)} at a value determined by the following formula 1 ^{_{(wherein, 0.1s -1 ≦ D 1 <D}} 2 ≦ 2s -1). Here, the thixotropy coefficient varies depending on the combination of the shear rate D ₁ and the shear rate D ₂ , but the active energy ray-curable resin composition of the present invention has a shear rate of 0.1 to 2 s ⁻¹ . thixotropic factor obtained by the equation 1 from the viscosity at any shear rate D ₁ and D ₂ is intended to be in the range of 1.1 to 10. The selection of the shear rate is generally set to D ₂ = D ₁ × 10.

The active energy ray curable resin composition of the present invention is within the combination range of the apparent viscosity and the thixotropy coefficient, and by adjusting the apparent viscosity and the thixotropy coefficient, the discharge property, the shape retention property of the bead-like ejector, the low diameter It is possible to variously adjust the balance between the expandability (shape accuracy) and the strength of the stiffness against the tensile stress at the time of application.
As a specific example of the adjustment, in the case of coating by discharging at a low pressure, it is a composition in which the thixotropy coefficient is adjusted so that the shape of the coated bead-shaped discharge body is maintained while adjusting the apparent viscosity to the lower limit side, On the other hand, when coating is performed by discharging at a high pressure, the apparent viscosity may be adjusted to the upper limit side and adjusted to a thixotropy coefficient that reduces the apparent viscosity in a high shear rate region to suppress the radial expansion. If the combination is outside the range of the apparent viscosity and the thixotropy coefficient of the present invention, the effect of the present invention is difficult to obtain. Specifically, when the apparent viscosity is less than 10 Pa · s and the thixotropy coefficient is less than 1.1, it is easy to discharge, but it is not preferable because it flows too much after discharge and is inferior in shape retention. In addition, when the apparent viscosity exceeds 4000 Pa · s and the thixotropy coefficient exceeds 10, the discharge pressure becomes high and the discharge becomes difficult, and in addition, it becomes easy to break against the tensile stress at the time of coating, or the radial expansion occurs. Since it becomes easy, it is not preferable.

3. Cured product of active energy ray curable resin composition The cured product obtained by irradiating the active energy ray curable resin composition of the present invention with an active energy ray and cured has an E hardness (conforming to JIS K6253) of 55 or less, More preferably, it is 50 or less, more preferably 40 or less, and the compression set is 35% or less under a 25% compression condition in a 70 ° C. temperature environment (according to JIS K6262), more preferably 30% or less. Yes, more preferably 20% or less. By setting it as the range of this characteristic, since it is low hardness and low compression set property is exhibited, it can be used suitably as a sealing material.

4). Container filled with active energy ray-curable resin composition The active energy ray-curable resin composition of the present invention is used for forming a sealing material or the like in a state of being filled in a container. The container in the present invention is sold as "a container filled and encapsulated with an active energy ray curable resin composition" in which the active energy ray curable resin composition of the present invention is filled and enclosed in a container. For example, a syringe, a tube, etc. are mentioned. Therefore, the container according to the present invention includes a fluid storage portion, a fluid inlet, a fluid outlet, a piston or impeller for injecting and extracting fluid, a cap, a seal, etc., and can store fluid. A container is included that has the ability to inject and / or dispense an amount. The container is further used with a needle-shaped coating portion that can be discharged in a bead shape. The needle-shaped coating portion may be previously attached to the container, or may be integrally formed. May be. Furthermore, when the active energy ray curable resin is an ultraviolet curable resin, it is preferable to use a light-shielding container in order to prevent the natural light from being cured by ultraviolet rays.

  The container filled with the active energy ray-curable resin composition only needs to include a fluid inlet, a fluid outlet, a piston or impeller for injecting or discharging fluid, a cap, a seal, and the like. The most frequently used ones include a container shaped like a syringe and a tube-type container. For example, in the case of a tube-type container, a type having a fluid inlet and a fluid outlet, a type having both a fluid inlet and a fluid outlet and only one port, and an initial fluid inlet and a fluid outlet. After injecting the fluid while holding it, the fluid inlet is sealed and only the fluid outlet is left.In the initial type, the fluid inlet and the fluid outlet are sealed and both are sealed. There are various types such as a type in which the means for sealing the inlet and the fluid outlet is selected from a stopper, a cap with a rotating groove, heat sealing or sealing. The container includes heating means, cooling means, decompression means, pressurization means, suction means, evaporation means, motor, hydraulic means, pneumatic means, weighing means, dustproof means, handling assist means, display means, and generated gas discharge means. Further, a backflow prevention unit or a temperature detection unit may be provided.

5). SEAL MATERIAL USING ACTIVE ENERGY RAY-CURABLE RESIN COMPOSITION AND METHOD FOR PRODUCING THE SAME At the same time or subsequently, the bead-shaped discharge member is irradiated with an active energy ray and cured to obtain a bead-shaped sealing material. The sealing material of the present invention has good sealing properties, low hardness and low resilience, so that the casing does not distort due to the resilience of the sealing material, and the compression set is small, so the sealing performance over time Since it is excellent in reliability, it is suitable as a sealing material for a small and thin casing.

The manufacturing method of the sealing material will be described in detail with reference to FIG. 1 as an example. Fig.1 (a) shows the front view of the coating device 9 which manufactures the bead-shaped sealing material 1, and FIG.1 (b) has shown the right view. As shown in FIG. 1 (a) and FIG. 1 (b), the container 5 filled with the active energy ray-curable resin composition of the present invention can be controlled to move in the XYZ axis directions. It is attached to the coating device 9. In the present embodiment, the container 5 is supplied with high-pressure air as a pressurizing means via a pressurized air supply pipe 90. As shown in FIG. 1A to FIG. 1C, a container 5 having a needle-like coating unit 4 is moved in accordance with a seal-shaped drawing pattern programmed in advance in a three-dimensional coating apparatus 9. The active energy ray-curable resin composition for the sealing material is discharged in the form of a bead onto the surface of the substrate to be coated 20 placed on the sample stage (stage) B from the needle-like coating portion 4 provided at the lower end of 5. Thus, the bead-shaped discharge body 10 is formed. Next, the active energy ray irradiating unit 8 irradiates the bead-shaped discharge body 10 with active energy rays, whereby the active energy ray-curable resin composition for sealing material constituting the bead-shaped discharge body 10 is cross-linked and the bead-shaped discharge body. 10 is cured, and the sealing material 1 is obtained. The pressurizing means for discharging the active energy ray-curable resin composition for sealing material from the needle-shaped coating portion 4 of the container 5 is exemplified by a pressurized air type using high-pressure air in FIG. A publicly known thing can be applied. Further, the bead-shaped discharge body 10 can be cured by irradiation with active energy rays at any time after discharge, but from the viewpoint of maintaining the shape of the bead-shaped discharge body 10, the needle-shaped coating that forms the bead-shaped discharge body 10. It is preferable that the discharge from the processing section 4 is almost simultaneously. Further, when manufacturing a higher sealing material, the bead-shaped discharge body 10 may be applied in two stages by being applied twice so as to overlap the bead-shaped discharge body on the formed bead-shaped discharge body.
The shape and diameter of the bead-shaped sealing material can be adjusted by the discharge hole diameter of the needle-shaped coating part and the coating conditions. The inner diameter (in the case of a circle) of the discharge hole of the needle-shaped coating part can be selected as appropriate depending on the application, but the effect of the present invention is exerted predominantly at 1 mm or less compared to the prior art, and is 0.75 mm or less. More preferably, it is remarkably exhibited at 0.5 mm or less.

The coating conditions include a discharge speed from the needle and a moving speed of the needle (more precisely, a moving speed of the needle discharge port). The discharge speed from the needle is appropriately adjusted according to the viscosity and thixotropy coefficient of the active energy ray-curable resin composition. However, since the discharge speed depends on the discharge pressure, if the discharge speed is too high (the discharge pressure is too high) And the bead-like ejector is twisted or shaken at the time of ejection, which is not preferable because problems such as unstable ejection and increased swell are likely to occur.
In addition, the moving speed of the needle is appropriately adjusted according to the balance with the discharge speed, but as the moving speed becomes larger than the discharge speed, the distance between the bead-shaped discharge body discharged onto the substrate to be coated and the needle discharge port is increased. Although the tensile stress applied to the bead-shaped discharge body is increased, the active energy ray-curable resin composition of the present invention is strong, so that the moving speed can be increased as compared with the conventional product. Further, the advantage of the strength of the stiffness may be utilized to increase the moving speed of the needle and intentionally apply a tensile stress to reduce the diameter of the bead-shaped discharge body. However, if the moving speed is too high, the bead-shaped discharge member is cut or the diameter of the bead-shaped discharge member becomes extremely thin, and the function as a bead-shaped sealing material is not preferable.

6). Other uses of the active energy ray curable resin composition The active energy ray curable resin composition of the present invention is ejected in a bead shape or a dot shape from at least two action members by a pressurizing means from a needle-like coating part. By disposing the discharge body and simultaneously or subsequently irradiating the discharge body with an active energy ray and curing it, various functions, for example, waterproof, dustproof, gap complementarity, rattling prevention, It can be suitably applied as a bead-like or dot-like sealing material that exhibits functions such as slip prevention and impact noise reduction. In addition to applications that are arranged between two action members, for example, a structure in which a plurality of bead-like or dot-like coating cured products are arranged on the surface of the casing by the CIP method, and impacts from the outside collide. The present invention is also effective for applications in which a buffering action is exerted at the time of application, and in applications in which one side is opened, such as when applied to a structure in which sealing properties and buffering properties are exhibited only when opposing members are close to each other.
Further, the excellent effect of the coating property of the active energy ray-curable resin composition of the present invention is remarkably exhibited when the inner diameter of the discharge hole of the needle-shaped coating portion is 1 mm or less. Even when the inner diameter of the discharge hole of the part exceeds 1 mm, it is excellent in coating property, shape retention, low resilience after curing, and low compression set, and thus can be suitably applied to such applications.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not particularly limited to these examples.

  Table 1 shows the specifications of the active energy ray-curable resin (A), the polymerization initiator (B), and the silica particles (C) constituting the active energy ray-curable resin used in the examples and comparative examples described below. To Table 3 below. The molecular weights of urethane (meth) acrylates A-9 and A-10 in Table 1 are values obtained by gel permeation chromatography (GPC), and GPC-104 (separation column LF-404 manufactured by SHODEX) is used as a measuring device. (3 connections), guard column LF-G, RI detector RI-74S (both manufactured by SHODEX)), eluent was tetrahydrofuran, sample concentration 10 mg / 4 ml, eluent flow rate 0.3 ml / min , And the column temperature was 40 ° C. Light acrylates in Table 1, Irgacure in Table 2, and Aerosil in Table 3 are registered trademarks.

The measurement methods of physical properties and the evaluation methods of effects in Examples and Comparative Examples are as follows.
(1) Apparent viscosity According to JIS Z8803 (cone-plate type rotational viscometer), using a corn plate type viscometer DT-3T manufactured by Brookfield, it was apparent at a shear rate of 1.0 s ^-1 at 25 ° C. The viscosity was measured.

(2) Thixotropy coefficient The thixotropy coefficient was calculated using Equation 1 above from the apparent viscosities at shear rates of 0.1 s ^-1 and 1.0 s ^-1 , which were measured by the same measurement method as the above (1) apparent viscosity.

(3) Hardness (low resilience)
On the transparent PET film, the active energy ray-curable resin composition was molded into a sheet shape so as to have a thickness of 2 mm after curing, and cured by irradiating 365 nm ultraviolet rays at ² J / cm ² each from the top surface and the bottom surface. Later, five sheets formed and cured in the same manner were stacked to form a measurement sample, and the hardness was measured using a type E durometer according to JIS K6253. The low resilience is evaluated from the measured hardness. When the E hardness is less than 50, “◯” (pass: good), when the E hardness is 50 or more and 55 or less, “Δ” (pass: acceptable), E hardness is 56 or more. The case was judged as “x” (failed).

(4) Compression set The active energy ray-curable resin composition was cast into a transparent resin mold having a diameter of 13 mm and a height of 6.3 mm, and irradiated with ² J / cm ^{2 of} 365 nm ultraviolet rays from the top and bottom surfaces. The cured product was used as a sample, and the strain rate after being held for 23 hours under a 25% compression condition in a 70 ° C. temperature environment according to JIS K-6262 was measured and evaluated. “O” (pass: good), more than 30% to 35% or less was judged as “Δ” (pass: acceptable), and more than 35% was judged as “x” (failed).

(5) Effect of reducing the diameter expansion (Swell) of the bead-shaped discharge body Fill the active energy ray-curable resin composition into a light-shielding syringe fitted with a needle having an inner diameter cross-sectional shape (discharge port diameter) and an inner diameter of 0.5 mm. The container was attached to an air pressurization type dispensing device (model Shotmaster (registered trademark) 200DS manufactured by Musashi Engineering Co., Ltd.) with an ultraviolet irradiation device, and an air pressure of 150 kPa was applied to the active energy ray curable resin from the needle. The composition was discharged to form a bead-like discharge body, and at the same time, UV irradiation was performed to obtain a bead-like cured product. The cross-sectional outer diameter (application width) of the bead-shaped cured product was measured with a microscope (MM-800 / LFA magnification of 20 times manufactured by Nikon Corporation), and the ratio ODb / the ratio of the discharge needle inner diameter IDn to the outer diameter ODb of the bead-shaped cured product. When evaluated by IDn, the case where the ratio was 1.5 or less was evaluated as “◯” (pass: good), and the case where the ratio exceeded 1.5 was determined as “x” (fail).

(6) Dischargeability (coatability)
Air pressurizing type dispensing apparatus in which a UV-irradiating device is attached to a container filled with an active energy ray-curable resin composition in a light-shielding syringe having a circular inner diameter cross-section (discharge port diameter) and a needle having an inner diameter of φ0.5 mm. (Model No. Shotmaster (registered trademark) 200DS manufactured by Musashi Engineering Co., Ltd.), 150 kPa air pressure is applied, the active energy ray-curable resin composition is discharged from the needle at 16 mm / s, and the needle is 15 mm / s. When the bead-shaped discharge body having the pattern shown in FIG. 2 is formed while moving at a speed of, the case where the active energy ray-curable resin composition can be discharged from the needle at 16 mm / s is indicated by “◯” (pass: good ), Discharge is possible, but the discharge speed is slower than the needle moving speed (15 mm / s), and the bead-shaped discharge body is extended There composition "△" (pass: Yes), or significantly discharge speed is low, and the discharge difficult compositions as "×" (failure).

(7) Shape retention property of bead-shaped discharge body (uncured state)
Air pressurizing type dispensing apparatus in which a UV-irradiating device is attached to a container filled with an active energy ray-curable resin composition in a light-shielding syringe having a circular inner diameter cross-section (discharge port diameter) and a needle having an inner diameter of φ0.5 mm. (A model shot master (registered trademark) 200DS manufactured by Musashi Engineering Co., Ltd.), and a glass plate (Hiraoka Glass Co., Ltd.) having the same discharge speed of each active energy ray-curable resin composition from the needle and the moving speed of the needle. A bead-shaped discharge body was formed on a soda glass. The bead-shaped discharge body was left to stand for 30 seconds, and the shape change (degree of sagging) of the bead-shaped discharge body was observed. The evaluation standard is that the width and height of the bead-shaped ejector are measured using a microscope (MM-800-LFA manufactured by Nikon), and the ratio (height / width) of the line height to the line width is 0.9 to 1 is “◎” (pass: excellent), 0.8 to less than 0.9 is “◯” (pass: good), 0.5 to less than 0.8 is “△” (pass: acceptable), 0.5 Less than "x" (failed) was set.

[Example 1]
Table 1 shows a (meth) acryloyl monomer (a) having a glycol unit and an alkyl group as the active energy ray-curable resin (A) in a plastic container with a lid, based on 100 parts by weight of the active energy ray-curable resin (A). A-1 is 54 parts by weight and A-4 is 7.5 parts by weight. As a (meth) acryloyl monomer (b) having a hydroxyl group in the molecule, A-6 is 6 parts by weight, and an alkyl (meth) acrylate monomer (c ) A-9 as 22.5 parts by weight, urethane acrylate as A-15 as 10 parts by weight, polymerization initiator (B) as B-1 and B-2 in Table 2 as 0.5 parts by weight, and silica 10 parts by weight of c-1 in Table 3 was added as particles (C), respectively, and 3 at 2000 rpm using a rotation / revolution mixer Awatori Rentaro ARE-250 manufactured by Sinky Corporation. To obtain an active energy ray curable resin composition was between kneading. Part of this active energy ray-curable resin composition is filled into a 50 ml internal light-shielding syringe and subjected to defoaming treatment using Awatron (registered trademark) AW-50 manufactured by Musashi Engineering Co., Ltd. A container filled with the resin composition was prepared and used as a sample for evaluating the effect of reducing the expansion of the diameter of the bead-shaped discharge body, the discharge performance, and the shape retention of the bead-shaped discharge body. On the other hand, the remaining active energy ray-curable resin composition that was not filled in the light-shielding syringe was used as a measurement sample for evaluation of apparent viscosity, thixotropy coefficient, hardness, and compression set.

[Examples 2 to 8]
An active energy ray-curable resin composition of each example was obtained in the same manner as in Example 1 except that the types and blends of the constituent materials were as shown in Table 4. Using the evaluation sample and measurement sample of the obtained active energy ray-curable resin composition, the physical properties were evaluated and the effects were evaluated.

[Examples 9 to 16]
The type and composition of each constituent material was as shown in Table 5, and the weight ratio (a) :( b) of (meth) acryloyl monomer (a) and (meth) acryloyl monomer (b) was mainly changed. Except that, the active energy ray-curable resin composition of each example was obtained in the same manner as in Example 1. Using the evaluation sample and measurement sample of the obtained active energy ray-curable resin composition, the physical properties were evaluated and the effects were evaluated.

[Examples 17 to 24]
Except that the type and composition of each constituent material is as shown in Table 6, except that the content of the (meth) acryloyl monomer (a2) contained mainly in the (meth) acryloyl monomer (a) was changed. The active energy ray-curable resin composition of each example was obtained by the same method as 1. Using the evaluation sample and measurement sample of the obtained active energy ray-curable resin composition, the physical properties were evaluated and the effects were evaluated.

[Example 25 to Example 34]
Configurations in which the types and blends of the constituent materials are as shown in Tables 7 and 8, and mainly the types and blending ratios of the alkyl (meth) acrylate monomer (c) {(a) + (b)}: (c) Except that, the active energy ray-curable resin composition of each example was obtained in the same manner as in Example 1. Using the evaluation sample and measurement sample of the obtained active energy ray-curable resin composition, the physical properties were evaluated and the effects were evaluated.

[Examples 35 to 38]
In the same manner as in Example 1, except that the type and composition of each constituent material is as shown in Table 8, and the weight ratio of the urethane acrylate contained in the active energy ray-curable resin (A) is mainly changed. The active energy ray curable resin composition of each Example was obtained. Using the evaluation sample and measurement sample of the obtained active energy ray-curable resin composition, the physical properties were evaluated and the effects were evaluated.

[Comparative Examples 1 to 9]
An active energy ray-curable resin composition of each comparative example was obtained in the same manner as in Example 1 except that each constituent material was each constituent and composition shown in Table 9. Using the evaluation sample and measurement sample of the obtained active energy ray-curable resin composition, the physical properties were evaluated and the effects were evaluated.

  From the results of Examples 1 to 38 shown in Tables 4 to 8, the active energy ray-curable resin composition composed of the composition of the present invention has good coatability, shape retention of discharged matter, and diameter accuracy. It was found that a cured product that can be realized and has both low resilience and low compression set can be obtained.

  Further, in Table 5, Examples 9 and 16 were carried out with respect to Examples 9 to 16 in which the weight ratio (a) :( b) between the (meth) acryloyl monomer (a) and the (meth) acryloyl monomer (b) was changed. From the viewpoint of reducing the low resilience and compression set, it is preferable that the range of (a) :( b) = 99: 1 to 70:30 is more preferable from the comparison between the results and the results of Examples 10-15. all right.

  The (meth) acryloyl monomer (a) is composed of a (meth) acryloyl monomer (a1) in which n in Formula 1 is 1 to 5 and a (meth) acryloyl monomer (a2) in which n is 6 to 20. In comparison with the results of Examples 17 and 23 in Table 6 and the results of Examples 18 to 22 and Example 24, the (meth) acryloyl monomer (a It was found that the weight ratio of the (meth) acryloyl monomer (a2) occupying 1) is more preferably 1% by weight or more and less than 90% by weight.

Moreover, the comparison of the result of Example 20 of Table 6 and the result of Example 24, the group of Examples 1, 2, 4, and 8 of Table 1, and Examples 25 to 28 and Examples 29 to 32 of Table 7 were made. From the comparison of the results with each of the groups and the results of Example 33 and Example 34 in Table 8, if the number of carbon atoms in R ₆ is 5 or more in the structure of the above formula 3, the alkyl (meth) acrylate monomer (c It was found that the effects of the present invention can be obtained even if the type of () is changed.

  Moreover, in Examples 35-38 of Table 8, from the comparison of the result of Example 35 and Examples 36-38, in order to make a compression set small, active energy ray-curable resin (A) is urethane ( It has been found that a structure containing (meth) acrylate is more preferable. Moreover, from the comparison of the results of Example 37 and Examples 36 and 38, when the weight average molecular weight of urethane (meth) acrylate is less than 6000 (Example 36), the ratio of urethane (meth) acrylate is 20% by weight. (Example 38), the E hardness increases as compared with Example 37, so that the active energy ray-curable resin (A) is a urethane having a weight average molecular weight of 6000 or more from the viewpoint of low resilience. It has been found that it is particularly preferable to contain less than 20% by weight of (meth) acrylate.

On the other hand, when the results of Comparative Examples 1 to 9 in Table 9 deviate from the range of the mixing ratio of each component of the present invention, ejection performance (coating property, shape retention, diameter accuracy) and cured product properties (low resilience) It has been found that an active energy ray-curable resin composition having all of (low compression set) cannot be obtained. Specifically, when the (meth) acryloyl monomer (a) in Formula 1 exceeds 20 as in Comparative Example 1 or when (meth) acryloyl monomer (b) in Comparative Example 2 as in Comparative Example 2, When R _{4 in} Formula 2 does not contain a methylene group, the compression set cannot be reduced, and the molecular weight of the (meth) acryloyl monomer (b) exceeds 110 as in Comparative Example 3. It was found that E hardness increases and low resilience cannot be obtained. Moreover, from the result of Comparative Example 5, the ratio of the total weight of the (meth) acryloyl monomer (a) and the (meth) acryloyl monomer (b) to the weight of the active energy ray-curable resin (A) is less than 50% by weight. In some cases, it was found that the compression set could not be reduced. Further, as in Comparative Example 4, when the weight ratio of the active energy ray curable resin (A) in the active energy ray curable resin composition is less than 80% by weight, or as in Comparative Example 6, the active energy ray It was found that when the weight ratio of the silica particles (C) in the curable resin composition exceeded 12% by weight, the viscosity was remarkably increased and ejection was impossible. Moreover, from the result of the comparative example 7, when the weight ratio of the silica particles (C) in the active energy ray-curable resin composition is less than 2% by weight, the shape retention of the discharged material is poor and the shape accuracy is high. It turned out that a discharge body cannot be obtained. Further, as in Comparative Example 5 and Comparative Example 8, the ratio of the total weight of (meth) acryloyl monomer (a) and (meth) acryloyl monomer (b) to the weight of alkyl (meth) acrylate monomer (c) {( a) + (b)}: When (c) is outside the range of 99: 1 to 50:50, or as in Comparative Example 9, the alkyl (meth) acrylate monomer (c) represented by R _{6 in} Formula 3 It has been found that when the carbon number is 4 or less, the compression set cannot be reduced.

  Although not described in the evaluation columns of Tables 4 to 8, the active energy ray-curable resin compositions of Examples 1 to 38 have a needle inner diameter of φ1 mm for evaluation of coatability, shape retention, and diameter accuracy. In this case, the result was the same as the case where the needle inner diameter was 0.5 mm.

  The active energy ray-curable resin composition of the present invention is suitably used for forming a sealing material by curing a bead-like or dot-like discharge by needle application, and is optimal as a sealing material for narrow spaces. This contributes to downsizing and cost reduction of electronic devices that incorporate them. Moreover, since the cured product of the active energy ray-curable resin composition of the present invention has low hardness and small permanent compression strain, it is suitable as a sealing material excellent in sealing performance and durability.

DESCRIPTION OF SYMBOLS 1 Bead-shaped sealing material 10 Bead-shaped discharge body 11 Active energy ray-curable resin composition 4 Needle-shaped coating part 5 Container filled with active energy ray-curable resin composition 8 Active energy ray irradiation unit 9 Three-dimensional control type Coating device 90 Pressure air supply pipe B Sample stage (stage)

Claims (8)

An active energy ray-curable resin composition comprising an active energy ray-curable resin (A), a polymerization initiator (B), and silica particles (C),
The active energy ray-curable resin (A) has the following formula (1) having an oligoglycol unit and an alkyl group in the molecule (wherein R ₁ is hydrogen or a methyl group, R ₂ is an alkyl group, W is an alkylene group) , N is an integer from 1 to 20.) and (meth) acryloyl monomer (a) represented by the following formula (2) having a hydroxyl group in the molecule (wherein R ₃ is hydrogen or a methyl group, R ₄ Is a (meth) acryloyl monomer (b) represented by the following formula (3) (wherein R ₅ is hydrogen or a methyl group, R ₆ is carbon: The total weight of the (meth) acryloyl monomer (a) and the (meth) acryloyl monomer (b), which is an alkyl (meth) acrylate monomer (c) represented by the following formula: Live The proportion of the energy ray curable resin (A) in the weight is 50% by weight or more, and the total weight of the (meth) acryloyl monomer (a) and the (meth) acryloyl monomer (b) and the alkyl (meth) acrylate monomer. (C) weight ratio {(a) + (b)}: (c) is 99: 1 to 50:50,
The weight ratio of the active energy ray-curable resin (A) in the active energy ray-curable resin composition is 80% by weight or more,
The active energy ray-curable resin composition, wherein a weight ratio of the silica particles (C) in the active energy ray-curable resin composition is 2 to 12% by weight.
  The weight ratio (a) :( b) between the (meth) acryloyl monomer (a) and the (meth) acryloyl monomer (b) is 99: 1 to 70:30. Active energy ray-curable resin composition.   The (meth) acryloyl monomer (a) comprises a (meth) acryloyl monomer (a1) in which n in the formula 1 is 1 to 5 and a (meth) acryloyl monomer (a2) in which n is 6 to 20. The weight ratio of the (meth) acryloyl monomer (a2) in the (meth) acryloyl monomer (a) is 1% by weight or more and less than 90% by weight. Resin composition.   The active energy ray-curable resin according to claim 1, wherein the active energy ray-curable resin (A) contains less than 20% by weight of urethane (meth) acrylate having a weight average molecular weight of 6000 or more. Resin composition. The viscosity of the active energy ray-curable resin composition in the range of a shear rate of 0.1 to 2 s ⁻¹ in an uncured state (cone-flat plate viscometer at 25 ° C. according to JIS Z8803) is 10 to 4000 Pa · s, and 5. The active energy ray-curable resin composition according to claim 1, wherein the thixotropic coefficient is 1.1 to 10, and E hardness after active energy ray curing (based on JIS K6253) is 55 or less. object.   The active energy ray-curable resin composition according to claim 1, wherein the compression set after active energy ray curing (JIS K6262 compliant, 70 ° C., 25% compression) is 35% or less.   The sealing material which consists of hardened | cured material of the active energy ray curable resin composition of any one of Claims 1-6. The active energy ray-curable composition according to claim 1 is applied to the surface of the substrate in a bead shape or a dot shape to form a discharge body, and the discharge body is irradiated with active energy rays and cured to form a sealing material. Forming a sealing material.