JP6763612B2 - Active energy ray-curable resin composition, sealing material and cushioning material made of the cured product - Google Patents

Description

The present invention relates to an active energy ray-curable resin composition and a cured product thereof. Specifically, the present invention is excellent in shape accuracy and productivity in discharge coating, and the cured product has an active energy ray-curable resin composition having low hardness and high cushioning property. The present invention relates to a sealing material and a cushioning material made of a material and a cured product thereof.

With the miniaturization of mobile information terminal devices such as mobile phones and smartphones and electronic devices such as digital cameras, the miniaturization and integration of components are progressing. For example, the sealing materials (packing, gaskets, etc.) used for the housings of these devices have also shifted to designs with narrow line widths, and at present, sealing materials having a width of about 1 mm are used. In addition, cushioning materials (shock absorbing materials) and anti-vibration materials used in small camera units and actuator units built into these devices are also becoming smaller. These components such as sealing materials, cushioning materials, and vibration-proofing materials are often made of soft materials, and due to their softness, the line width of the sealing materials becomes narrower, and the size of the cushioning materials and vibration-proofing materials is extremely small. In that case, it becomes difficult to incorporate the components into the housing or the like, which reduces productivity and causes an increase in cost.

As a countermeasure, in Patent Document 1 and Patent Document 2, a liquid sealing material such as an ultraviolet curable resin is discharged from a needle in a bead shape (linearly) and applied to a portion where the sealing material is attached to a housing or the like (hereinafter, A method (so-called "cured-in-place method": hereinafter referred to as "CIP method") is proposed in which a bead-shaped ejector is cured with ultraviolet rays to directly form a sealing material and at the same time attached to a housing or the like. Has been done. Further, in order to improve the discharge property (coatability) of such a liquid sealing material and the shape retention of the applied bead-shaped discharge body before curing, Patent Document 1 describes an ultraviolet curable resin. A technique for adding silica particles is described, and Patent Document 2 describes a technique for adjusting the viscosity of a coating material such as an ultraviolet curable resin to about 1 to 1000 Pa · s at a coating temperature.

On the other hand, when a sealing material or a cushioning material is incorporated into a member such as a housing that has been thinned for miniaturization, if the resilience is large, the housing or the like is easily deformed. Is required to have low resilience, that is, sufficiently flexible and low hardness. In addition, electronic components such as personal digital assistants, digital cameras, and wearable electronic devices are densely integrated due to miniaturization, and in recent years, various sensors have been implemented, and the electronic components are damaged or erroneously depending on the usage pattern and environment. For the purpose of preventing operation, sealing materials and cushioning materials are required to have better cushioning and vibration isolation.

Therefore, Patent Documents 3 and 4 propose an energy ray-curable resin composition in which an acrylic compound and a polyfunctional thiol compound are mixed as a constitution of an ultraviolet curable resin for obtaining a flexible sealing material. In Patent Documents 5 to 7, a photocurable resin composition using an acrylic monomer is proposed, and in Patent Document 8, an active energy ray-curable resin composition in which a urethane acrylate oligomer and an acrylic monomer are mixed is proposed. ..

Japanese Unexamined Patent Publication No. 07-88430 Japanese Unexamined Patent Publication No. 2004-289943 Japanese Unexamined Patent Publication No. 2010-254853 JP-A-2010-260918 Japanese Unexamined Patent Publication No. 2004-26919 International Publication No. 2002/044299 Japanese Unexamined Patent Publication No. 2014-80498 Japanese Unexamined Patent Publication No. 2003-105320

However, in the techniques described in Patent Document 1 and Patent Document 2, 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 becomes to discharge the liquid sealing material, and when the liquid sealing material is discharged at high pressure. If the bead-shaped discharge body expands in diameter (swell) or the viscosity of the liquid sealing material is lowered in order to prioritize the discharge property, the bead-shaped discharge body will sag after application and the line width of the sealing material will be widened, which is desired to be thin. There has been a problem and a problem that it becomes difficult to obtain a sealing material having a line width.

Further, although Patent Document 1 and Patent Document 2 describe that an ultraviolet curable resin is cured to obtain a sealing material, a sealing material having sufficient flexibility and high cushioning and vibration-proofing properties is provided. The composition of the UV curable resin for obtaining has not been studied. Further, the energy ray-curable resin compositions described in Patent Documents 3 and 4 have a large number of cross-linking points and are sufficiently soft because a large amount of a cross-linking agent composed of a polyfunctional thiol is added to the acrylic compound. It was difficult to obtain a cured product such as a sealing material having the above. As for the resin compositions described in Patent Documents 5 to 8, it was not possible to obtain a cured product such as a sealing material or a cushioning material having sufficient flexibility. As described above, the composition of the active energy ray-curable resin for obtaining the sealing material and the cushioning material having sufficient flexibility and high cushioning and vibration-proofing properties has not been sufficiently studied.

The present invention has been made in view of the above points, and an object of the present invention is to have fluidity and chixolotopy suitable for the CIP method, and to reduce the diameter of the needle discharge port in order to obtain a sealing material having a narrow line width. Even in the case, the activity of forming a cured product having excellent coatability and shape accuracy, sufficient flexibility (low hardness) and high cushioning and vibration isolation properties (loss coefficient: large tan δ) after curing. The present invention is to provide an energy ray curable resin composition. The loss coefficient tan δ in the present invention is defined as a value obtained by dividing the loss elastic modulus G ″ in the dynamic viscoelastic property by the storage elastic modulus G ′.

Another object of the present invention is to provide a sealing material, a cushioning material, a vibration-proof material, etc., which have sufficient flexibility (low hardness) and high cushioning / vibration-proofing property (loss coefficient: large tan δ). There is.

In order to solve the above problems, the active energy ray-curable resin composition of the present invention comprises a photopolymerizable oligomer (A), a photopolymerizable monomer (B), a photopolymerization initiator (C) and a thixotropic agent (D). The photopolymerizable oligomer (A) is a urethane (meth) acrylate having an ether bond having a mass average molecular weight of 10,000 or more, and the photopolymerizable monomer (B) has the following formulas (1) (in the formula). , R ₁ is a hydrogen atom or a methyl group, W is an ethylene group or a propylene group, and n is an integer of 0 to 4). The (meth) acryloyl compound (b1) is a photopolymerizable monomer (B1). ) Is contained in an amount of 80% by mass or more, and the total content (A + B) of the photopolymerizable oligomer (A) and the photopolymerizable monomer (B) is the photopolymerizable oligomer (A) and the photopolymerization. It is 94 to 99.99% by mass with respect to the total mass (A + B + C) of the sex monomer (B) and the photopolymerization initiator (C), and the content of the photopolymerizable monomer (B) is the photopolymerizable oligomer (B). It is 80 to 99% by mass with respect to the total mass (A + B) of A) and the photopolymerizable monomer (B), and the thixotropy-imparting agent (D) is a photopolymerizable oligomer (A) and a photopolymerizable monomer (B). ) And the photopolymerization initiator (C) totaling (A + B + C) 100 parts by mass, containing 1 to 40 parts by mass, and in an uncured state, the viscosity at a shear rate of 0.1 to 2s ^-1 is 10 to 5000 Pa. -S and the chixotropy coefficient in the range of the shear rate of 0.1 to 2s ^-1 is 1.1 to 10.

By adopting urethane (meth) acrylate having an ether bond having a mass average molecular weight of 10,000 or more as the photopolymerizable oligomer (A) constituting the active energy ray-curable resin composition, excellent cushioning property and vibration isolation property are obtained. A cured product having (high loss coefficient) and flexibility (low hardness) can be obtained. Further, since the (meth) acryloyl compound (b1) represented by the formula (1) is contained in an amount of 80% by mass or more of the total mass of the photopolymerizable monomer (B), it has excellent cushioning and vibration isolation (high loss). A cured product having a coefficient) can be obtained. Further, the total content (A + B) of the photopolymerizable oligomer (A) and the photopolymerizable monomer (B) is adjusted to the photopolymerizable oligomer (A), the photopolymerizable monomer (B) and the photopolymerization initiator (C). The curing reaction is preferably made by setting 94 to 99.99% by mass with respect to the total mass (A + B + C). Further, by setting the content of the photopolymerizable monomer (B) to 80 to 99% by mass with respect to the total mass (A + B) of the photopolymerizable oligomer (A) and the photopolymerizable monomer (B), the cured product is obtained. It is possible to achieve both excellent cushioning and vibration isolation (high loss coefficient) and flexibility (low hardness). Then, the thixotropy-imparting agent (D) is added in an amount of 1 to 40 parts by mass with respect to 100 parts by mass of the total (A + B + C) of the photopolymerizable oligomer (A), the photopolymerizable monomer (B) and the photopolymerization initiator (C). By containing it, suitable thixotropic properties can be obtained while achieving both excellent cushioning and vibration isolation (high loss coefficient) and flexibility (low hardness). Further, in the uncured state, the viscosity at a shear rate of 0.1 to 2s ^-1 is 10 to 5000 Pa · s, and the thixotropy coefficient in the range of a shear rate of 0.1 to 2s ^-1 is 1.1 to 10. As a result, an active energy ray-curable resin composition having fluidity and thixotropy suitable for the CIP method and having excellent coatability and shape accuracy can be obtained even when the diameter of the needle discharge port is reduced. The active energy ray-curable resin composition having each configuration of the present invention has an E hardness (JIS K6253 compliant) of 40 or less and dynamic viscoelasticity by irradiating and curing the active energy ray. It has physical properties with a loss coefficient of 0.3 or more at 10 Hz in measurement (JIS K7244-10 compliant), and has sufficient flexibility (low hardness) and excellent cushioning and vibration isolation (large loss coefficient). A cured product can be formed.

Further, the polymerizable monomer (B) in the active energy ray-curable resin composition of the present invention further includes the following formula (2) (in the formula, R ₂ is a hydrogen atom or a methyl group, Y is an ethylene group or a propylene group. It is also preferable that m contains a (meth) acryloyl compound (b2) represented by (each of which represents an integer from 0 to 20). As a result, in addition to the above-mentioned effects, the compression set of the cured product can be reduced. Further, the content of the (meth) acryloyl compound (b2) represented by the formula (2) is represented by the (meth) acryloyl compound (b1) represented by the formula (1) and the (meth) acryloyl represented by the formula (2). It is also preferable that it is 0.1 to 5% by mass with respect to the total mass (b1 + b2) of the compound (b2). As a result, it is possible to reduce the compression set while achieving both excellent cushioning and vibration isolation (high loss coefficient) and flexibility (low hardness) of the cured product.

Further, it is also preferable that the thixotropy-imparting agent (D) in the active energy ray-curable resin composition of the present invention is silica fine particles, and the carbon content of the silica fine particles is less than 0.5% by mass. As a result, a suitable substance as a thixotropy-imparting agent is selected.

Further, it is also preferable that the photopolymerization initiator (C) in the active energy ray-curable resin composition of the present invention comprises at least two or more kinds of compounds, and at least one kind is a phosphine-based compound or an aminoalkylphenone-based compound. As a result, the stickiness of the surface of the cured product cured by irradiation with light energy rays is reduced or the compression set is improved.

Further, it is also preferable that the sealing material or cushioning material of the present invention is made of a cured product of the above-mentioned active energy ray-curable resin composition. As a result, a sealing material and a cushioning material having excellent flexibility, cushioning and vibration isolation can be obtained.

According to the present invention, it is possible to provide an active energy ray-curable resin composition having the following excellent effects, and a sealing material and a cushioning material made of the cured product thereof.
(1) The active energy ray-curable resin composition of the present invention is excellent in ejection property at the time of needle application, and the diameter expansion (Swell) of the bead-shaped ejection body is unlikely to occur, and the ejection shape accuracy of the bead-shaped ejection body is high. Since it is high and has excellent shape retention after coating, it is possible to produce a sealing material or a cushioning material having high shape accuracy with high productivity.
(2) Since the cured product of the active energy ray-curable resin composition of the present invention has low hardness and a large loss coefficient, it is a sealing material, cushioning material, or vibration-proof material having excellent flexibility, cushioning property, and vibration-proofing property. Materials and the like can be obtained.
(3) Further, by adjusting the components contained in the photopolymerizable monomer (B) constituting the active energy ray-curable resin composition of the present invention, the loss coefficient of the cured product can be further improved, or the cured product can be further improved. The compression set can be reduced.
(4) The active energy ray-curable resin composition of the present invention is suitable for forming a bead-shaped sealing material or the like to which a needle is applied by using a needle having a small diameter of 1 mmφ or less, and particularly, the inner diameter is 0. When a needle with an ultra-fine diameter of .75 mmφ or less is used, the diameter expansion (Swell) of the bead-shaped ejector is less likely to occur, the diameter accuracy of the bead-shaped ejector is excellent, and the shape retention after coating is high. It has the effect of. In addition, the cured product has low hardness and a large loss coefficient, so it is excellent in flexibility, cushioning and vibration isolation. Therefore, it is possible to obtain a sealing material that is flexible and has excellent cushioning properties, a cushioning material that has excellent shock absorption, and an anti-vibration material while realizing an ultra-fine wire diameter, and it is possible to reduce the size of electronic devices that incorporate these materials. Contributes to cost reduction.

It is explanatory drawing which shows the coating apparatus which discharges the active energy ray curable resin composition of this invention in a bead shape to form a bead shape discharge body, and irradiates the active energy ray, and the state of coating. It is a schematic diagram which shows the coating pattern of the bead-shaped discharge body for test in an Example.

The active energy ray-curable resin composition of the present invention (hereinafter, may be simply referred to as a resin composition or a curable resin composition) includes a photopolymerizable oligomer (A), a photopolymerizable monomer (B), and the like. It contains a photopolymerization initiator (C) and a thixotropy-imparting agent (D). In the active energy ray resin composition of the present invention, the mixed composition of the photopolymerizable oligomer (A) and the photopolymerizable monomer (B) is polymerized and cured by being irradiated with the active energy ray. Hereinafter, each component will be described in detail.

1. 1. Photopolymerizable oligomer (A)
The photopolymerizable oligomer (A) used in the active energy ray-curable resin composition of the present invention has a polymerizable functional group that can be cured by active energy rays, and is a component that contributes to the loss coefficient after curing. Therefore, it is a urethane (meth) acrylate having a plurality of ether bonds in the molecule and having a mass average molecular weight of 10,000 or more. The mass average molecular weight of the photopolymerizable oligomer (A) is more preferably 15,000 or more, and further preferably 20,000 or more, from the viewpoint of improving the loss coefficient of the cured product. When the number of polymerizable functional groups of the photopolymerizable oligomer (A) is less than 2, unpolymerized photopolymerizable oligomers bleed on the surface of the cured product of the active energy ray-curable resin composition. As a result, defects in the sealing property and appearance of the cured product may occur, and in the case of 5 or more, the crosslink density may become too high and the hardness thereof may increase, so 2 to 4 are preferable. The presence of an ether bond in the molecule of the photopolymerizable oligomer (A) is indispensable because it greatly contributes to the flexibility of the molecular structure of urethane (meth) acrylate and the reduction of hardness (low resilience) of the cured product. .. The blending ratio of the photopolymerizable oligomer (A) enhances the buffering performance of the cured product (increases the loss coefficient) with respect to the total mass (A + B) of the photopolymerizable oligomer (A) and the photopolymerizable monomer (B) described later. ), 1 to 20% by mass is preferable, 1 to 15% by mass is more preferable, and 3 to 10% by mass is further preferable. Specific examples of the photopolymerizable oligomer (A) include Shikou (registered trademark) series manufactured by Nippon Kayaku Chemical Co., Ltd. (for example, UV-6640B, UV-3300B, UV-3700B, etc.) and Hitachi Kasei Co., Ltd. Hitaroid® series (eg, 4861, 7981, etc.), Art Resin (registered trademark) series manufactured by Negami Kogyo Co., Ltd. (eg, UN-6202, UN-6301, UN-5590, KHP-22, etc.), Asia SUA series manufactured by Kogyo Co., Ltd. (for example, SUA-008, SUA-015, etc.), KUA series manufactured by KSM Co., Ltd. (for example, KUA-PEA2I, KUA-PEC2I, etc.), KAYARAD (registered trademark) manufactured by Nippon Kayaku Co., Ltd. Series UX (for example, UXF-4002, UXF-4001, etc.) can be mentioned, but the present invention is not limited thereto.

2. 2. Photopolymerizable monomer (B)
The photopolymerizable monomer (B) used in the active energy ray-curable resin composition of the present invention has a polymerizable functional group that can be cured by active energy rays and polymerizes with the above-mentioned photopolymerizable oligomer (A). It is a possible ingredient. The photopolymerizable monomer (B) contains at least a monomer component composed of the (meth) acryloyl compound (b1) represented by the above formula (1).

2-1. (Meta) Acryloyl compound (b1)
This (meth) acryloyl compound (b1) (hereinafter, may also be referred to as the first (meth) acryloyl compound (b1)) has a (meth) acryloyl group at the molecular end as described in the above formula (1). It has a molecular structure having a phenyl group and further having ethyl ether or propyl ether in the molecule. In the (meth) acryloyl compound (b1) represented by this formula (1), R ₁ is a hydrogen atom or a methyl group, W is an ethylene group or a propylene group, and n is an integer of 0 to 4. The value of n in the formula (1) is preferably an integer of 0 to 4, because when n is 5 or more, the loss coefficient of the cured product becomes small and good buffering performance cannot be obtained. Further, the molecular weight of the (meth) acryloyl compound (b1) is more preferably 192 to 325. In the case of the (meth) acryloyl compound (b2) having a molecular weight of less than 192, that is, a compound having no portion indicated by a glycol group, the hardness of the cured product increases (increases in impact resilience) due to the decrease in acrylic equivalent, and This is because the amount of curing shrinkage during curing may increase and the shape accuracy may decrease, and when the molecular weight becomes 326 or more, the loss coefficient of the cured product may decrease and the cushioning property may decrease. Specific examples of the compound represented by the formula (1) include phenoxyethyl acrylate, phenoxypropyl acrylate, phenoxydiethylene glycol acrylate, phenoxydipropylene glycol acrylate, phenoxytriethylene glycol acrylate, phenoxytripropylene glycol acrylate, and phenoxyethyl meta. Examples thereof include acrylate, phenoxypropyl methacrylate, phenoxydiethylene glycol methacrylate, phenoxydipropylene glycol methacrylate, phenoxytriethylene glycol methacrylate, etc. Among them, phenoxydiethylene glycol acrylate, phenoxydi from the viewpoint of balance between hardness and loss coefficient. Propylene glycol acrylate and phenoxydiethylene glycol methacrylate are preferably used.

The ratio of the (meth) acryloyl compound (b1) to the total mass of the photopolymerizable monomer (B) improves the loss coefficient of the cured product at 10 Hz in the dynamic viscoelasticity measurement, and from the viewpoint of obtaining good cushioning performance. , 80% by mass or more is preferable, 85% by mass or more is more preferable, and 90% by mass or more is further preferable. By adopting the (meth) acryloyl compound (b1) represented by the formula (1) as the photopolymerizable monomer (B) constituting the resin composition of the present invention, the loss coefficient is large, and the cushioning property and vibration isolation are achieved. A cured product having excellent properties can be obtained.

The blending ratio of the photopolymerizable monomer (B) is preferably 80 to 99% by mass, preferably 85 to 99% by mass, based on the total mass (A + B) of the photopolymerizable oligomer (A) and the photopolymerizable monomer (B). % Is more preferable, and 90 to 97% by mass is further preferable. If the compounding ratio of the photopolymerizable monomer (B) is less than 80% by weight, the loss coefficient at 10 Hz in the dynamic viscoelasticity measurement of the cured product becomes small, so that good buffering performance cannot be obtained, and photopolymerization If the compounding ratio of the sex monomer (B) exceeds 99% by weight, the curability of the active energy ray-curable resin composition is significantly lowered, which is not preferable. The compound constituting the photopolymerizable monomer (B) may be composed of only the (meth) acryloyl compound (b1) described above, but any monomer compound that can be polymerized with the photopolymerizable oligomer (A) is the first compound. It may be configured in combination with the (meth) acryloyl compound (b1) of. Among these, as a preferable example of the other monomer compound constituting the photopolymerizable monomer (B), the monomer compound represented by the above formula (2) will be described in detail below.

2-2. (Meta) Acryloyl compound (b2)
By using the first (meth) acryloyl compound (b1) in combination as the photopolymerizable monomer (B) and the (meth) acryloyl compound (b2) represented by the formula (2), the cured product is permanently compressed. Distortion is reduced. This (meth) acryloyl compound (b2) (hereinafter, may also be referred to as a second (meth) acryloyl compound (b2)) has (meth) acryloyl groups at both ends of the molecule as shown in the formula (2). It is composed of a molecular structure having ethyl ether or propyl ether in the molecule. In the (meth) acryloyl compound (b2) represented by this formula (2), R ₂ is a hydrogen atom or a methyl group, Y is an ethylene group or a propylene group, and m is an integer of 0 to 20. Regarding the value of m in the formula (2), m = 0, that is, the cured product may become too hard when there is no ethyl ether or propyl glycol unit, and when m exceeds 20, the cured product may become too hard. Since the value of the compressive permanent strain of the above may be large, it is preferably an integer of 1 to 20, more preferably 3 to 20, and even more preferably 5 to 20. Here, the compression set is the value of the compression set after being held for 23 hours under a 25% compression condition under a temperature environment of 70 ° C. indicated by JIS K6262. Specific examples of the (meth) acryloyl compound (b2) represented by the formula (2) include light esters manufactured by Kyoeisha Chemical Co., Ltd. (EG, 2EG, 3EG, 4EG, 9EG, 14EG) and light acrylates manufactured by Kyoeisha Chemical Co., Ltd. (Registered Trademarks) Series (3EG-A, 4EG-A, 9EG-A, 14EG-A), KAYARAD (Registered Trademarks) Series (PEG400DA) manufactured by Nippon Kayaku Co., Ltd., Aronix (Registered Trademarks) manufactured by Toagosei Co., Ltd. Series (M-220, M-225, M-240, M-270), NK Ester (A-200, A-400, A-600, APG-100, APG-200, APG) manufactured by Shin-Nakamura Chemical Co., Ltd. -400, APG-700) and the like.

The blending ratio of the first (meth) acryloyl compound (b1) and the second (meth) acryloyl compound (b2) is the first (meth) acryloyl compound (b1) and the second (meth) acryloyl compound (b2). The ratio of the second (meth) acryloyl compound (b2) to the total mass of) is preferably 0.1 to 5% by mass. When the ratio of the second (meth) acryloyl compound (b2) is less than 0.1% by mass, it is difficult to obtain effects such as reduction of the compression set of the cured product, and when it exceeds 5% by mass, the E hardness of the cured product is obtained. This is because, as the value increases and becomes harder, the value of the loss coefficient becomes smaller, and the shock absorption performance may deteriorate.

3. 3. Photopolymerization initiator (C)
The active energy ray-curable resin composition of the present invention contains a photopolymerization initiator (C) for initiating the polymerization of the photopolymerizable oligomer (A) and the photopolymerizable monomer (B). The photopolymerization initiator (C) is preferably used in combination of at least two or more kinds of compounds, one of which is preferably a phosphine-based compound or an aminoalkylphenon-based compound, and a phosphine-based compound and an aminoalkylphenon-based compound. It is more preferable to use it in combination with a compound.

When a phosphine-based compound is used as the photopolymerization initiator (C), the energy on the long wavelength side of near ultraviolet rays can be effectively utilized in the polymerization initiation reaction, so that the internal curability of the active energy ray-curable resin composition is enhanced. It is also effective in reducing the compression set of the cured product. The above-mentioned phosphine-based compound is a compound containing a phosphine oxide group represented by P = O in the molecule, and more specifically, a compound in which a phosphine group and an acyl group are bonded in the molecule. is there. The phosphine-based compound is not particularly limited, but is not particularly limited.
2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,6-dimethylbenzoyldiphenylphosphine oxide, 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2,6-dichlorobenzoyldiphenylphosphine oxide, 2,3,5,6- Monoacylphosphine oxide compounds such as tetramethylbenzoyldiphenylphosphine oxide; bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl-pentyl Bisacylphosphinoxide-based compounds such as phosphine oxide; 2,4,6-trimethylbenzoylphenylphosphinic acid methyl ester, 2,4,6-trimethylbenzoylphenylphosphinic acid ethyl ester, 2,4,6-trimethylbenzoylphenylphosphinic acid Phenyl esters and their analogs are well known, and examples of commercially available products include LUCIRIN (registered trademark) TPO, TPO-L, and IRGACURE (registered trademark) 819 manufactured by BASF.

When an aminoalkylphenone-based compound is used as the photopolymerization initiator (C), the energy in the short to medium wavelength region of near ultraviolet rays can be effectively utilized for the curing initiation reaction, so that the surface of the active energy ray-curable resin composition The effect of improving the curability of the cured product can be obtained, and the stickiness of the surface of the cured product can be reduced. The aminoalkylphenone-based compound is not particularly limited, but is 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone, 2- (dimethylamino) -2-[(). 4-Methylphenyl) Methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone, 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one and these Relatives are well known, and commercially available products include 907, 369, 379EG of the IRGACURE (registered trademark) series manufactured by BASF.

The blending ratio of the photopolymerization initiator (C) is 0.01 to 6 with respect to the total mass (A + B + C) of the photopolymerizable oligomer (A), the photopolymerizable monomer (B) and the photopolymerization initiator (C). It is preferably 0.1 to 5% by mass, more preferably 0.5 to 3% by mass. If the blending ratio of the photopolymerization initiator is less than 0.01% by mass, curing by active energy ray irradiation does not proceed sufficiently, and if it exceeds 6% by mass, unreacted light remaining in the polymer structure after curing This is because the polymerization initiator volatilizes and becomes outgas, which may cause a problem when incorporated into an electronic device. Therefore, the total content (A + B) of the photopolymerizable oligomer (A) and the photopolymerizable monomer (B) is that of the photopolymerizable oligomer (A), the photopolymerizable monomer (B) and the photopolymerization initiator (C). It is preferably in the range of 94 to 99.99 mass%, more preferably 95 to 99.9 mass%, and further preferably 97 to 99.5 mass% with respect to the total mass (A + B + C). preferable.

4. Thixotropy-imparting agent (D)
In the active energy ray-curable resin composition of the present invention, a thixotropic agent (D) is added to the resin material component composed of the above-mentioned photopolymerizable oligomer (A), photopolymerizable monomer (B) and photopolymerization initiator (C). ) Is blended and dispersed. By being dispersed in the resin material, the thixotropy-imparting agent (D) can impart thixotropy, that is, a property that the viscosity is high in the low shear rate region and the viscosity is low in the high shear rate region. It refers to all agents, for example, a compound that swells when added to a resin material and forms a loose stitch structure due to a relatively weak bonding force such as hydrogen bonding force or van der Waals force. Can be mentioned. These are commercially available as paint additives under the names of anti-sagging agent, anti-sedimentation agent, thixotropy agent and the like. The resin composition in which the thixotropy-imparting agent is uniformly dispersed has a high apparent viscosity in the low shear rate region because a gentle stitch structure is maintained, and the stitch structure is destroyed by the shear force in the high shear rate region. Therefore, it exhibits the property of lowering the viscosity.

Specific examples of such a thixotropy-imparting agent (D) include long-chain fatty acid ester polymers, amido wax, polyethylene oxide wax, sulfate ester-based anion activators, polycarboxylic acids, polycarboxylic acid amine salts, and polyethers. Organic compounds such as fine silica, calcium carbonate, heavy calcium carbonate, bentonite, sepiolite and other inorganic fine particles, and Teflon (registered trademark), silicone and other resin fine particles can be preferably used, and the shape of the fine particles is spherical. It can be appropriately used in a rod shape or a scale shape. Of these, as the thixotropy-imparting agent (D) in the present invention, silica fine particles are more preferable, and fumed silica fine particles are further preferable, from the viewpoint of the balance between fluidity and thixotropy. Further, among the fumed silica fine particles, hydrophilic silica fine particles that have not been subjected to hydrophobic treatment are particularly preferably used. By using hydrophilic silica fine particles as the thixotropy-imparting agent (D), the desired viscosity before curing can be obtained with a small amount of addition, and the E hardness (JIS K6253 compliant) of the cured product after curing can be increased. It can be kept to a minimum and a large loss factor can be maintained. Here, the fumed silica fine particles are a general term for aggregates obtained by treating a silane compound in a high temperature atmosphere, and the obtained aggregates are compounds composed of silicon, oxygen and hydrogen, similarly to glass. It is generally called hydrophilic silica. In addition, fumed silica fine particles are industrially used in various fields, and a treatment called hydrophobization may be performed depending on the application and manufacturing method. This hydrophobic treatment is carried out by treating hydrophilic silica with a compound having an organic functional group containing carbon, and therefore the hydrophobic silica fine particles contain a carbon component. Therefore, from the viewpoint of having hydrophilicity, the carbon content of the silica fine particles is preferably low, and specifically, the carbon content of the silica fine particles is less than 0.5% by mass with respect to the entire silica fine particles, which is more preferable. Is 0.3% by mass or less, more preferably 0.1% by mass or less, and it is particularly preferable that the carbon component is substantially not contained. Specific examples of silica fine particles include AEROSIL (registered trademark) manufactured by Aerosil Japan, REOLOSIL (registered trademark) manufactured by Tokuyama Corporation, CAB-O-SIL (registered trademark) manufactured by CABOT, and WACKER HDK (registered trademark) manufactured by Asahi Kasei Wacker Co., Ltd. Examples include fumed silica, NIPSIL (registered trademark) of Nippon Silica Industry Co., Ltd., Silicon (registered trademark) of Fuji Silicia, and TOKUSIL (registered trademark) of Tokuyama Corporation.

When the fine particles such as the silica fine particles are dispersed in the active energy ray-curable resin composition, the primary particles agglomerate to form a network structure, and the thixotropy property is imparted due to this network structure. The primary particle size of the fine particles is selected so that the dispersibility in the resin material, the effect of imparting thixotropy, and the viscosity are in a preferable state of the present invention. Specifically, 0.002 to 10 μm is preferable, and more preferably 0. It is .005 to 1 μm, more preferably 0.007 to 0.1 μm. For the numerical value of the primary particle size of the fine particles, the longest diameter of the contour of each of 1000 randomly selected primary particle images of 1000 fine particles is measured in an image at a magnification at which the primary particles can be visually recognized by SEM or TEM (transmission electron microscope). , It is a numerical value obtained by additive averaging. The specific surface area (DIN66131 compliant BET method) corresponding to the primary particle size is 0.3 to 600 m ² / g, more preferably 3 to 430 m ² / g, and more preferably 3 to 430 m ² / g when the fine particles are silica. Is 30-600 m ² / g.

The blending amount of the thixotropy-imparting agent (D) is 1 to 40 mass by mass with respect to 100 parts by mass of the total (A + B + C) of the photopolymerizable oligomer (A), the photopolymerizable monomer (B) and the photopolymerization initiator (C). is preferably part, more preferably 2 to 30 parts by weight in the case of using the silica fine particles thixotropic agent as (D), more preferably 3 to 20 parts by weight, 3 to 15 parts by weight is particularly preferred. If the amount of the thixotropy-imparting agent (D) added is less than 1 part by mass, good thixotropy cannot be obtained, and if it exceeds 40 parts by mass, the E hardness of the cured product becomes too large and the loss coefficient becomes small. Is.

If necessary, the active energy ray-curable resin composition of the present invention may contain other additives as long as the effects of the present invention are not impaired. Examples of other additives include fillers, and include not only powder fillers but also conductive agents, antistatic agents, flame retardants, buffering improvers, colorants and the like. Examples of these powder fillers include crystalline silica, molten silica, calcium carbonate, talc, mica, alumina, aluminum hydroxide, white carbon and the like. Further, carbon black, expanded graphite powder, powdered graphite, metal fine particles, or the like can be used to impart conductivity and static elimination property. As the flame retardant, powdered organic halogen compounds, red phosphorus, antimony trioxide, expanded graphite, magnetite, aluminum hydroxide and the like can be used. As the buffering property improving agent, a hollow filler having an organic shell (for example, Expandel (registered trademark) manufactured by Nippon Philite Co., Ltd.) can be used. Examples of the colorant include various pigments and dyes, and these additives may be appropriately selected and used depending on the intended use.

Further, the active energy rays that cure the active energy ray-curable resin composition of the present invention 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 preferable. Used for. 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). Further, 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 resin composition can be coated on the substrate to be coated or cured in a short time after being coated, and is not particularly limited. For example, a low-pressure mercury lamp, a high-pressure mercury lamp, or an excima. Known generating means such as an ultraviolet (exima UV) lamp, a halide lamp, an LED light, or a laser can be used. Further, examples of the infrared ray source include a lamp, a resistance heating plate, a laser, and the like, and examples of the visible light source include direct sunlight, a lamp, a fluorescent lamp, an LED light, a laser, and the like. Examples of the source of the electron beam include a commercially available device that utilizes thermions generated from a tungsten filament, a cold cathode method that generates a metal through a high voltage pulse, and an ionized gaseous molecule and a metal electrode. Examples thereof include a secondary electron type device that utilizes secondary electrons generated by collision. Further, examples of sources of alpha rays, beta rays and gamma rays include fissile materials such as Co60, and for gamma rays, a vacuum tube or the like that causes accelerated electrons to collide with the anode can be used. These active energy rays may be irradiated alone or in combination of two or more.

5. Physical properties of the 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 discharge material is less likely to expand in diameter (Swell) and has high shape retention after coating. In order to achieve the effect, the viscosity when uncured is 10 to 5000 Pa · s (JIS Z8803 compliant conical-plate type rotational viscometer 25 ° C.) and the shear rate is 0.1 to 0.1 at a shear rate of 0.1 to 2s ^-1 . It is important that the thixotropy coefficient in the range of 2s ^-1 is 1.1-10.

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 exhibits the characteristics of a non-Newtonian fluid, the viscosity of the active energy ray-curable resin composition of the present invention is apparent. This refers to the viscosity, which will be described below as the apparent viscosity. The apparent viscosity of the active energy ray-curable resin composition of the present invention in an uncured state (hereinafter, may be simply referred to as apparent viscosity) is the viscosity obtained by a conical-plate type rotational viscometer in JIS Z8803 (1991). according measurement methods ", at 25 ° C. under a measured value in the range of shear rate 0.1～2S ^-1, it is specifically a value measured at a shear rate of 1.0 s ^-1 Is preferable. The uncured state is a state in which the active energy ray-curable resin composition is not irradiated with the active energy rays for curing. The apparent viscosity of the active energy ray-curable resin composition of the present invention is preferably 10 to 5000 Pa · s, more preferably 20 to 5000 Pa · s, further preferably 30 to 1000 Pa · s, and particularly preferably 50 to 800 Pa · s. .. If the apparent viscosity is less than 10 Pa · s, it will flow too much after being discharged from the needle or the like and the shape retention will be poor. If it is more than 5000 Pa · s, it will be difficult to discharge from the needle or the like and the tensile stress at the time of coating will be applied. However, it is not preferable because it is easy to cut and the diameter is easily expanded. The apparent viscosity is such that the thixotropy-imparting agent (D) is dispersed in the photopolymerizable oligomer (A), the photopolymerizable monomer (B) and the photopolymerization initiator (C) and then left to stand, and the change in viscosity is 5% or less. It is preferable that the viscosity and thixotropy coefficient are in the range of / day.

If the thixotropy coefficient (hereinafter, also simply referred to as the thixotropy coefficient) of the active energy ray-curable resin composition of the present invention is less than 1.1, it flows too much after being discharged from the needle, resulting in shape retention. Inferior, if it is more than 10, it becomes difficult to discharge from the needle, the bead-shaped discharger is easily cut due to the tensile stress at the time of application, and the diameter expansion is likely to occur. Preferably, 2 to 9 are more preferable, and 2.5 to 8 are even more preferable. Here, the thixotropy coefficient (TI) is the apparent viscosity η (D ₁ ) at the shear rate D ₁ measured by a JIS Z8803 compliant conical-plate type rotational viscometer (25 ° C.) and the shear rate D _2. It is a value obtained by the following equation 1 from the apparent viscosity η (D ₂ ) in (however, 0.1s ^-1 ≤ D ₁ <D ₂ ≤ 2s ^-1 ). Here, the thixotropy coefficient changes 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 in the range of 0.1 to 2s ^-1 . The thixotropy coefficient obtained by the following formula 1 from each viscosity at arbitrary shear velocities D ₁ and D _{2 is} in the range of 1.1 to 10. The shear rate is generally selected as D ₂ = D ₁ × 10.

The active energy ray-curable resin composition of the present invention has a discharge property, a bead-like ejector shape retention property, and a low diameter by adjusting the apparent viscosity and thixotropy coefficient within the range of the combination of the apparent viscosity and the thixotropy coefficient. The balance between expandability (shape accuracy) and stiffness against tensile stress during coating can be adjusted in various ways. To adjust the apparent viscosity and thixotropy coefficient, for example, in the case of discharging and coating at a low pressure, the thixotropy coefficient is adjusted so that the shape of the bead-shaped discharger coated while adjusting the apparent viscosity to the lower limit side is maintained. When the composition is adjusted, on the other hand, when the coating is applied by discharging at high pressure, the apparent viscosity is adjusted to the upper limit side and the thixotropy coefficient is adjusted so that the apparent viscosity becomes smaller in the high shear rate range to suppress the diameter expansion. do it. Combinations outside the range of the apparent viscosity and thixotropy coefficient of the present invention make it difficult to obtain the effects of the present invention. Specifically, when the apparent viscosity is less than 10 Pa · s and the thixotropy coefficient is less than 1.1, it becomes easy to discharge, but it flows too much after discharge and is inferior in shape retention, which is not preferable. Further, when the apparent viscosity exceeds 5000 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 due to the tensile stress at the time of coating and the diameter expands. It is not preferable because it becomes easy.

6. Physical properties of the cured product of the active energy ray-curable resin composition The cured product obtained by irradiating the active energy ray-curable resin composition of the present invention with active energy rays and cured has an E hardness (JIS K6253 compliant) of 40 or less. Yes, and the loss coefficient at 10 Hz in the dynamic viscoelasticity measurement (JIS K7244-10 compliant) is 0.3 or more. When the cured product falls within this range of physical properties, it has low hardness and low resilience, and exhibits excellent cushioning and vibration isolation. Further, by appropriately adjusting the compounding component of the polymerizable monomer (B), the compression set can be reduced, so that it is also suitable as a sealing material. In particular, when applied to a sealing material, the compounding components of the active energy ray-curable resin composition are adjusted so that the value of compression set is 50% or less, more preferably 40% or less, still more preferably 30% or less. do it.

7. 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 container-filled manner. The container in the present invention is sold as a "container filled / sealed with the active energy ray-curable resin composition in an uncured state" in which the active energy ray-curable resin composition of the present invention is filled / sealed in the container. Examples thereof include syringes and tubes. Therefore, the container in the present invention is provided with a fluid storage part, a fluid inlet, a fluid inlet / outlet, a piston or an impeller for injecting / discharging a fluid, a cap, a seal, etc., and can store the fluid, which is optional. Includes containers capable of injecting and / or injecting volumes. The container is further attached with a needle-shaped coating portion capable of discharging in a bead shape, but the needle-shaped coating portion may be attached to the container in advance or is integrally formed. You may. Further, when the active energy ray-curable resin is an ultraviolet curable type, it is preferable to use a light-shielding container in order to prevent curing by ultraviolet rays of natural light.

The container filled with the active energy ray-curable resin composition may be provided with a container selected from a fluid inlet, a fluid inlet / outlet, a piston or impeller for injecting / or injecting fluid, a cap, a seal, and the like. The most frequently used ones are containers in the form of syringes and tube-shaped containers. For example, in the case of a tube type container, a type that has a fluid inlet and a fluid inlet, a type that has both a fluid injection and a fluid injection and has only one port, and an initial fluid inlet and a fluid inlet. A type that closes the fluid inlet after injecting fluid while holding it and leaves only the fluid inlet, a type that initially has a fluid inlet and a fluid inlet but then seals both after injecting fluid, fluid injection There are various types such as a type in which the means for sealing the inlet and the fluid inlet / outlet is selected from a stopper, a cap with a rotating groove, a heat seal, a seal sticking, and the like. The container includes heating means, cooling means, decompression means, pressurizing means, suction means, evaporation means, motor, hydraulic means, pneumatic means, measuring means, dustproof means, handling assisting means, display means, generated gas discharging means. , Backflow prevention means, temperature detection means, etc. may be installed side by side.

8. Method for Producing Active Energy Ray Curable Resin Composition The active energy ray curable resin composition for a sealing material of the present invention is produced by a known method for producing a resin composition. Specifically, as an example, a photopolymerizable oligomer (A), a photopolymerizable monomer (B), and photopolymerization using a kneader such as a single-screw extruder, a twin-screw extruder, a kneader, a Banbury mixer, or a roll mill. It is produced by adding a thixotropy-imparting agent (D) to a resin material in which the initiator (C) is kneaded, further kneading the mixture, and uniformly dispersing the mixture.

9. Sealing material using the active energy ray-curable resin composition and its manufacturing method The active energy ray-curable resin composition of the present invention is discharged from the needle-like coating portion in a bead shape by a pressurizing means to form a bead-like discharge body. Then, at the same time or subsequently, the bead-shaped discharger is irradiated with active energy rays and cured to obtain a bead-shaped sealing material. Since the sealing material of the present invention has good sealing properties, low hardness and low resilience, it can be used stably without distorting the housing due to the repulsive force of the sealing material. Further, since the compression set is small and the sealing property is excellent over time, it is suitable as a sealing material for a small and thin housing.

The method for producing the sealing material will be described in detail with reference to FIG. 1 as an example. FIG. 1A shows a front view of a coating device 9 for manufacturing a bead-shaped sealing material 1, and FIG. 1B shows a right side view thereof. As shown in FIGS. 1A and 1B, the container 5 filled with the active energy ray-curable resin composition of the present invention can be moved and controlled in the XYZ axes in three dimensions. It is attached to the coating device 9. In the present embodiment, high-pressure air is supplied to the container 5 as a pressurizing means via the compressed air supply pipe 90. As shown in FIGS. 1 (a) to 1 (c), the container 5 provided with the needle-shaped coating unit 4 moves according to a seal-shaped drawing pattern programmed in the three-dimensional coating device 9 in advance, and is a container. The active energy ray-curable resin composition for a sealing material is discharged in a bead shape from the needle-shaped coating portion 4 provided at the lower end of 5 to the surface of the substrate 20 to be coated placed on the sample table (stage) B. The bead-shaped discharge body 10 is formed. Next, by irradiating the bead-shaped discharge body 10 with active energy rays from the active energy ray irradiation unit 8, the active energy ray-curable resin composition for a sealing material constituting the bead-shaped discharge body 10 is crosslinked to form a bead-shaped discharge body. 10 is cured to obtain a sealing material 1. As the pressurizing means for discharging the active energy ray-curable resin composition for a sealing material from the needle-shaped coating portion 4 of the container 5, the pressurized air type using high-pressure air was exemplified in FIG. 1, but the hydraulic or gear pump type was used. Any known material such as is applicable. Further, the bead-shaped discharge body 10 can be cured by irradiation with active energy rays at any time after the discharge, but from the viewpoint of maintaining the shape of the bead-shaped discharge body 10, a needle-like coating for forming the bead-shaped discharge body 10 is possible. It is preferable that the discharge from the work unit 4 is almost simultaneous. Further, in the case of producing a higher sealing material, the bead-shaped discharge body 10 may be stacked in two stages by coating the bead-shaped discharge body twice so as to be overlapped on the formed bead-shaped discharge body. The shape and diameter of the bead-shaped sealing material can be adjusted by adjusting the discharge hole diameter of the needle-shaped coating portion and the coating conditions. The inner diameter (in the case of a circular shape) of the discharge hole of the needle-shaped coating portion can be appropriately selected depending on the application, but when it is 1 mm or less, the action and effect of the present invention are superiorly exhibited as compared with the prior art, and 0.75 mm or less. , More preferably, it is remarkably exhibited at 0.5 mm or less. The coating conditions include the discharge speed from the needle-shaped coating portion and the movement speed of the needle (to be exact, the movement speed of the needle discharge port). The discharge rate from the needle is appropriately adjusted by the viscosity and thixotropy coefficient of the active energy ray-curable resin composition. However, since the discharge rate depends on the discharge pressure, if the discharge speed is too large (the discharge pressure is too large). And), the bead-shaped discharge body is twisted or shaken at the time of discharge, and problems such as unstable discharge state and large diameter expansion (swell) are likely to occur, which is not preferable. Further, the moving speed of the needle-shaped coating portion is appropriately adjusted in balance with the discharging speed, but the larger the moving speed than the discharging speed, the more the bead-shaped discharging body and the needle-shaped coating discharged on the substrate to be coated. The tensile stress applied to the bead-shaped discharger increases with the discharge port of the work part, but the active energy ray-curable resin composition of the present invention has a strong stiffness, so that the moving speed is higher than that of the conventional product. can do. Further, the diameter of the bead-shaped ejector may be reduced by increasing the moving speed of the needle-shaped coated portion and intentionally applying tensile stress by utilizing the advantage of the strength of the stiffness. .. However, if the moving speed is too high, the bead-shaped discharge body is cut or the diameter of the bead-shaped discharge body becomes extremely small, and the bead-shaped discharge body does not function as a bead-shaped sealing material, which is not preferable.

10. Cushioning material using active energy ray-curable resin composition and its manufacturing method The active energy ray-curable resin composition of the present invention is discharged from a needle-shaped coating portion in a bead shape or a dot shape by a pressurizing means. A cushioning material can be formed at a desired location by forming the body and simultaneously or subsequently irradiating the discharge body with active energy rays to cure it. Since the cushioning material of the present invention has a large loss coefficient, it has excellent cushioning performance. The method of adjusting the shape and diameter of the pressurizing means and the cushioning material is omitted because it is the same as the sealing material described above.

11. Other Uses of Cured Product of Active Energy Ray Curable Resin Composition The cured product of the active energy ray curable resin composition of the present invention is beaded between at least two working members by a pressurizing means from a needle-like coating portion. By arranging the discharge bodies by discharging them in a shape or a dot shape, and simultaneously or subsequently irradiating the discharge bodies with active energy rays to cure them, various applications such as waterproofing, dustproofing, and vibration-proofing are used. It can also be suitably applied to applications such as vibration suppression, stress relaxation, gap complementation, rattling prevention, slip prevention, and collision noise reduction. Further, the application is not limited to the use of being arranged between two working members. For example, as a structure in which a plurality of bead-shaped or dot-shaped coated cured products are arranged on the surface of a housing by the CIP method, an impact object from the outside collides. It is also effective for applications where one side is open, such as when it is applied to a structure that exerts a cushioning action when it is used, or when it is applied to a structure that exerts a sealing property or a buffering property only when opposing members are close to each other. .. Further, the excellent coatability 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 coated portion is 1 mm or less, but that of the needle-shaped coated portion. Even when the inner diameter of the discharge hole exceeds 1 mm, it is excellent in coatability, shape retention, low resilience after curing, cushioning property, etc., and therefore can be suitably applied to various applications as described above.

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 photopolymerizable oligomer (A), the photopolymerizable monomer (B), the photopolymerization initiator (C), and the thixotropy-imparting agent (D) used in Examples and Comparative Examples described below. ~ Shown in Table 4. The weight average molecular weight of each material A-1 to A-5 of the photopolymerizable oligomer (A) shown in Table 1 is a value measured by a gel permeation chromatography (GPC) method, and specifically, as a measuring device, THFEX. GPC-104 manufactured by GPC-104 (separation column LF-404 (three connected), guard column LF-G, RI detector RI-74S (all manufactured by SHODEX)) was used, and tetrahydrofuran was used as an eluent, and the sample concentration was 10 mg. It is a value measured under the conditions of / 4 mL, eluent flow rate 0.3 mL / min, and column temperature 40 ° C.

As the photopolymerizable monomer (B) shown in Table 2, materials B-1 to B-5 are used as the first (meth) acryloyl compound (b1), and material B is used as the second (meth) acryloyl compound (b2). -6 to B-10 were used, and materials B-11 to B-13 were used as other acryloyl compounds. Of these, the phenoxytetraethylene glycol acrylate, which is the material B-4, was produced and used in the required amounts in the following Examples and Comparative Examples. As a specific production method, 24.8 g of tetraethylene glycol monoacrylate (Blemmer AP-200, manufactured by Nichiyu Co., Ltd.) is refluxed in 160 mL of tetrahydrofuran with 10.5 g of sodium carbonate while stirring for 1 hour. After that, 17.3 g of bromobenzene was added dropwise, and the mixture was further refluxed for 4 hours and then cooled to room temperature. The reaction solution was filtered, tetrahydrofuran was distilled off, and then silica gel chromatography was passed to obtain a phenoxytetraethylene glycol acrylate of material B-4.

The method for measuring the physical properties of the resin composition (uncured product) and the cured product thereof and the method for evaluating the effect in Examples and Comparative Examples are as follows.
(1) Apparent viscosity According to JIS Z8803 (conical-plate type rotational viscometer), using a cone plate type viscometer DT-3T manufactured by Brookfield, apparent viscosity at a shear rate of 1.0 s ^-1 at 25 ° C. The viscosity was measured.

(2) thixotropy coefficient above (1) was measured in the same manner as the apparent viscosity, the apparent viscosity of a shear rate 0.1s ^-1 and 1.0 s ^-1, was calculated thixotropic coefficients using the equation (1).

(3) Loss coefficient (buffering property)
The active energy ray-curable resin composition was formed into a sheet on a transparent PP film so as to have a thickness of 2 mm after curing, and was cured by irradiating ² J / cm ² of ultraviolet rays of 365 nm from the top surface and the bottom surface. .. The sheet-shaped cured product was punched to φ29 mm and molded to prepare a measurement sample. For the measurement, a rheometer (ARES-G2, a product of TA Instruments Japan Co., Ltd.) was used to measure the loss coefficient at 25 ° C. and 10 Hz (JIS K7244-10 compliant). The cushioning property is evaluated from the measured loss coefficient, and when the loss coefficient is 0.3 or more, the buffering property is "○" (good), and when the loss coefficient is less than 0.3, the buffering property is "x" (nonconforming). I decided.

(4) Hardness (flexibility / low resilience)
The active energy ray-curable resin composition was formed into a sheet on a transparent PET film so as to have a thickness of 2 mm after curing, and was cured by irradiating ² J / cm ² of ultraviolet rays of 365 nm from the top surface and the bottom surface. .. Five sheet-shaped cured products thus obtained were stacked to prepare a measurement sample. For the measurement, the E hardness was measured using a type E durometer according to JIS K6253. The flexibility was evaluated from the measured E hardness, and it was judged that the flexibility was "○" (good) when the E hardness was 40 or less, and the flexibility was "x" (nonconforming) when the E hardness was more than 40.

(5) Compressed Permanent Strain The active energy ray-curable resin composition is 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 ultraviolet rays of 365 nm from the top and bottom surfaces. The cured sample was used as a measurement sample. According to JIS K-6262, the distortion factor after holding for 23 hours under a 25% compression condition under a temperature environment of 70 ° C. was measured.

(6) Diameter accuracy: Reduction of diameter expansion (Swell) of bead-shaped discharger A light-shielding syringe equipped with a needle having a circular cross-sectional shape and an inner diameter of φ0.5 mm is filled with an active energy ray-curable resin composition. The container was attached to an air-pressurized dispensing device (Musashi Engineering Co., Ltd. model Shotmaster (registered trademark) 200DS) to which an ultraviolet irradiation device was attached. An air pressure of 400 kPa was applied to discharge an active energy ray-curable resin composition from a needle having an inner diameter of φ0.5 mm to form a bead-shaped ejector, and at the same time, UV irradiation was performed to obtain a bead-shaped cured product. The cross-sectional outer diameter (coating width) of the bead-shaped cured product was measured with a microscope (Nikon MM-800 / LFA magnification 20 times), and the ratio ODb / of the discharge needle inner diameter IDn to the outer diameter ODb of the bead-shaped cured product. Evaluated by IDn, the diameter accuracy was rated as "○" (good) when the ratio was 1.5 or less, and the diameter accuracy was rated as "x" (nonconforming) when the ratio exceeded 1.5.

(7) Workability (discharge)
An air-pressurized dispensing device with an ultraviolet irradiation device attached to a container filled with an active energy ray-curable resin composition in a light-shielding syringe equipped with a needle having a circular discharge port and an inner diameter of φ0.5 mm. It was attached to Musashi Engineering's model shot master (registered trademark) 200DS). As shown in FIG. 2, an air pressure of 400 kPa is applied to discharge the active energy ray-curable resin composition from a needle having an inner diameter of φ0.5 mm in a bead shape at 16 mm / s, and the needle is moved at a speed of 15 mm / s. A bead-shaped discharger having the pattern shown was formed. At this time, when the active energy ray-curable resin composition can be discharged from the needle at 16 mm / s, the coatability is "○" (good), and the active energy ray-curable resin composition can be discharged, but the discharge is higher than the needle moving speed (15 mm / s). A composition with a slow speed and a bead-like discharger that easily stretches has a coatability of "△" (semi-good), and a composition with a significantly low discharge rate or a composition that is difficult to discharge has a coatability of "x" (nonconforming). did.

(8) Shape retention of bead-shaped discharger in uncured state A container filled with an active energy ray-curable resin composition in a light-shielding syringe equipped with a needle having a circular cross-sectional shape and an inner diameter of φ0.5 mm. Was attached to an air-pressurized dispensing device (Musashi Engineering Co., Ltd. model Shotmaster (registered trademark) 200DS) to which an ultraviolet irradiation device was attached. A bead-shaped discharger was formed on a glass plate (soda glass manufactured by Hiraoka Glass Co., Ltd.) by making the discharge speed of the active energy ray-curable resin composition from a needle having an inner diameter of φ0.5 mm and the movement speed of the needle the same. .. The bead-shaped discharger was allowed to stand naturally for 30 seconds, and the shape change (degree of sagging) of the bead-shaped discharger was observed. The evaluation standard is to measure the width and height of the bead-shaped ejector 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. When it is 1, the shape retention is "◎" (excellent), when it is less than 0.8 to 0.9, the shape retention is "○" (good), and when it is less than 0.5 to 0.8, the shape is retained. When the property was "Δ" (semi-good) and less than 0.5, the shape retention was "x" (nonconforming).

[Example 1]
In a plastic container with a lid, as shown in Table 5, 10 parts by mass of the material A-1 as the photopolymerizable oligomer (A) and the first (meth) acryloyl compound (b1) as the photopolymerizable monomer (B). 90 parts by mass of a certain material B-1 was taken, and the total of the photopolymerizable oligomer (A) and the photopolymerizable monomer (B) was taken as 100 parts by mass. To this, 0.5 parts by mass of material C-1 and 0.5 parts by mass of material C-2 were added as a photopolymerizable initiator (C), and 6.4 parts of material D-1 was added as a thixotropy-imparting agent (D). Added parts by mass. Next, this mixture is kneaded at 2000 rpm for 3 minutes using a rotation / revolution mixer (product name: Awatori Rentaro (registered trademark) ARE-250, Shinky Co., Ltd. product) to make an active energy ray-curable resin. The composition was obtained. A part of this active energy ray-curable resin composition is filled in a light-shielding syringe having an internal volume of 50 mL, and a centrifugal defoaming machine for syringes (product name: Awatron (registered trademark) AW-50, Musashi Engineering Co., Ltd. product) is used. A container filled with the active energy ray-curable resin composition was prepared by defoaming, and used as a sample for evaluating the diameter accuracy, coatability, and shape retention of the bead-shaped ejector. 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 sample for measuring apparent viscosity, thixotropy coefficient, loss coefficient, hardness, and compression set. Using these samples, the physical properties of the active energy ray-curable resin composition obtained in Example 1 were measured and evaluated.

[Examples 2 to 24]
The active energy ray-curable resin compositions of Examples 2 to 24 were obtained in the same manner as in Example 1 except that the constituents were the materials and formulations shown in Tables 5 to 9. Physical properties were measured and evaluated using the evaluation sample and the measurement sample of the active energy ray-curable resin composition obtained in each example. The results are shown in Tables 5-9.

[Example 25]
In a plastic container with a lid, as shown in Table 9, 20 parts by mass of the material A-1 as the photopolymerizable oligomer (A) and the first (meth) acryloyl compound (b1) as the photopolymerizable monomer (B). 80 parts by mass of a certain material B-1 was taken, and the total of the photopolymerizable oligomer (A) and the photopolymerizable monomer (B) was taken as 100 parts by mass. To this, 5 parts by mass of material D-5 as a thixotropy-imparting agent (D) was added, and the mixture was allowed to stand at 100 ° C. for 15 minutes, and the contents were stirred in a state where the thixotropy-imparting agent (D) was melted. After cooling to room temperature, 0.5 parts by mass of material C-3 and 0.5 parts by mass of material C-4 are added as a photopolymerizable initiator (C), and this mixture is mixed with a rotation / revolution mixer (product name: Awa). The active energy ray-curable resin composition of Example 25 was obtained by kneading at 2000 rpm for 3 minutes using Tori Rentaro (registered trademark) ARE-250, a product of Shinky Co., Ltd. Then, in the same manner as in Example 1, the physical properties were measured and evaluated using the obtained sample for evaluation and the sample for measurement of the active energy ray-curable resin composition. The results are shown in Table 9.

[Examples 26 to 31]
The active energy ray-curable resin compositions of Examples 26 to 31 were obtained in the same manner as in Example 1 except that the constituents were the materials and formulations shown in Table 10. Physical properties were measured and evaluated using the evaluation sample and the measurement sample of the active energy ray-curable resin composition obtained in each example. The results are shown in Table 10.

[Comparative Examples 1 to 15]
The active energy ray-curable resin compositions of Comparative Examples 1 to 11 and Comparative Examples 13 to 15 were obtained in the same manner as in Example 1 except that the constituents were the materials and formulations shown in Tables 11 to 13. .. Further, the active energy ray-curable resin composition of Comparative Example 12 was obtained in the same manner as in Example 25 except that the constituent components were the materials and formulations shown in Comparative Example 12 in Table 13. In the same manner as in Example 1, the physical properties of each active energy ray-curable resin composition obtained in Comparative Examples 1 to 15 were measured and evaluated. The results are shown in Tables 11 to 13.

From the evaluation results of Examples 1 to 31 shown in Tables 5 to 10, the active energy ray-curable resin composition of the present invention is excellent in needle coatability, shape retention and diameter accuracy, and the cured product is E. It was found that it had physical properties with a hardness of 40 or less and a loss coefficient of 0.3 or more, and was also excellent in flexibility and cushioning properties. Although not described in the evaluation column of Tables 5 to 10, the active energy ray-curable resin compositions of Examples 1 to 31 have needles for evaluation of diameter accuracy, coatability and shape retention. Even when the coating was performed using a needle having an inner diameter of φ1 mm, the result was the same as when a needle having an inner diameter of φ0.5 mm was used. Furthermore, it was found that the compression set can be reduced by adjusting the material used as a constituent component and the blending ratio thereof within the scope of the composition of the present invention.

Specifically, it was found that the following configurations (i) to (vi) are important for obtaining the active energy ray-curable resin composition having the action and effect of the present invention.
(I) From the comparison of the evaluation results of Examples 11 to 12 and Comparative Example 1 and the evaluation results of Examples 1 to 10 and Examples 13 to 31, the photopolymerizable oligomer (A), the photopolymerizable monomer (B) and The ratio of the total content (A + B) of the photopolymerizable oligomer (A) and the photopolymerizable monomer (B) to the total mass (A + B + C) of the photopolymerization initiator (C) is in the range of 94 to 99.99% by weight. There is.
(Ii) From the comparison of the evaluation results of Examples 1 to 31 and Comparative Examples 8 to 11 and the comparison of the evaluation results of Example 10 and Comparative Example 7, the photopolymerizable monomer (B) is derived from the structure of the above formula 1. The (meth) acryloyl compound (b1) is contained, and the ratio of the (meth) acryloyl compound (b1) to the photopolymerizable monomer (B) is 80% by weight or more.
(Iii) From the comparison of the evaluation results of Examples 1 to 31 and Comparative Examples 4 to 6, the photopolymerizable oligomer (A) is a urethane (meth) acrylate having an ether bond and having a weight average molecular weight of 10,000 or more. There is.
(Iv) From the comparison of the evaluation results of Examples 8 to 9 and Comparative Examples 2 to 3 and the evaluation results of Examples 1 to 25, the total mass (A + B) of the photopolymerizable oligomer (A) and the photopolymerizable monomer (B) ), The content of the photopolymerizable monomer (B) is 80 to 99% by mass.
(V) From the comparison of the evaluation results of Examples 20 to 21 and Comparative Examples 13 to 14 and the results of Examples 1 to 25, the addition ratio of the thixotropy-imparting agent (D) was determined by the photopolymerizable oligomer (A) and photopolymerization. 1 to 40% by mass based on 100 parts by mass of the total (A + B + C) of the sex monomer (B) and the photopolymerization initiator (C).
(Vi) From the comparison of the evaluation results of Examples 1 to 31 and Comparative Example 15, the photopolymerizable monomer (B) contains the first (meth) acryloyl compound (b1) represented by the formula (1). Moreover, the value of n in the equation (1) is an integer of 0 to 4.

Further, from the comparison of the results of Examples 20 to 21 and Comparative Examples 13 to 14, the results of Examples 1 to 31, and the results of Examples 20 and 25 and Comparative Examples 12 to 13, the active energy ray curing The apparent viscosity of the sex resin composition is 10 to 5000 Pa · s, and the thixotropy coefficient is in the range of 1.1 to 10 to realize excellent coatability, shape retention of bead-shaped ejector, and diameter accuracy. It turned out to be important to do.

Further, as shown in the evaluation results of Examples 2 to 4, Examples 11 to 16 and Examples 22 to 23, as the photopolymerizable monomer (B), the first (meth) acryloyl of the above formula (1) was used. It was found that the compression set of the cured product can be reduced by using the compound (b1) in combination with the second (meth) acryloyl compound (b2) of the above formula (2). Further, from the results of Examples 2 and 13 to 16, the first (meth) acryloyl compound (b1) and the second (meth) acryloyl compound (b2) were found in the blending ratio of the photopolymerizable monomer (B). When the content of the second (meth) acryloyl compound (b2) with respect to the total mass of the active energy ray-curable resin composition is in the range of 0.1 to 5% by weight, the E hardness, loss coefficient and E-hardness of the cured product of the active energy ray-curable resin composition and It was found that the physical properties of compression set were improved in a well-balanced manner.

Further, from the results of Examples 2 and 28 to 31, in the second (meth) acryloyl compound (b2) represented by the formula (2), the larger the value of m in the formula (2), the more the curing. It was found that m is preferably in the range of 1 to 20 because the measured value of the compression set of the object becomes large.

Further, from the comparison of the results of Examples 2 and 22 to 23, when the thixotropy-imparting agent (D) is silica fine particles, the smaller the carbon content of the silica fine particles, the smaller the E hardness of the cured product, and the loss coefficient. It was found that a cured product having a large value, low hardness and excellent cushioning property was obtained, and it was particularly preferable that the carbon content of the silica fine particles was less than 0.5% by weight.

Further, from the comparison between Examples 2 and 17 to 18 and Example 19, when the photopolymerizable initiator (C) is hydroxyalkylphenon-based Example 19, the evaluation column in Table 8 shows. Although not described, the photopolymerizable initiator (C) is at least a phosphine-based compound or at least a phosphine-based compound because the surface adhesiveness of the cured product may be strong or a portion that is insufficiently cured may be generated on the surface. It has been found that an aminoalkylphenon-based compound is more preferable. Further, it was found that the combined use of the phosphine compound and the aminoalkylphenon compound as in Example 2 further excellent the compression set of the cured product.

Furthermore, from the results of Example 25, it was found that the effect of the present invention can be obtained even when the organic compound amidowax is applied as the thixotropy-imparting agent (D), as in the case where the silica fine particles are applied.

On the other hand, as in Comparative Example 1, the total content (A + B) of the photopolymerizable oligomer (A) and the photopolymerizable monomer (B) is the photopolymerizable oligomer (A) and the photopolymerizable monomer (B). ) And the photopolymerization initiator (C) in excess of 99.99% by weight based on the total mass (A + B + C), or as in Comparative Examples 2 and 3, the photopolymerizable oligomer (A) and the photopolymerizable monomer The composition of the present invention is the composition of the active energy ray-curable resin composition having a composition in which the compounding ratio of (B) is out of the range of the composition of the present invention, and the compounding ratio of the thixotropic agent (D) as in Comparative Examples 13 to 14. Even if the active energy ray-curable resin composition out of the range of is excellent in needle coatability, shape retention, and diameter accuracy, the cured product has an E hardness of 41 or more and / or a loss coefficient of 0. It was found that the value was less than 3, the hardness was high, the flexibility and cushioning property were poor, and the effect of the present invention could not be obtained. Further, as in Comparative Examples 4 to 6, when the photopolymerizable oligomer (A) does not have an ether bond or the weight average molecular weight is less than 10,000, the E hardness of the cured product is 41 or more, and the hardness becomes high. It was found that the effect of the present invention could not be obtained because the flexibility was greatly reduced. Further, when the photopolymerizable monomer (B) does not contain the first (meth) acryloyl compound (b1) as in Comparative Examples 8 to 11, or as in Comparative Example 7, the photopolymerizable monomer (B) ), Even when the ratio of the first (meth) acryloyl compound (b1) is less than 80% by weight, the loss coefficient of the cured product is less than 0.3 and the buffering property is poor. Turned out not to be obtained. Further, as in Comparative Examples 12 to 14, when the viscosity and thixotropy coefficient of the active energy ray-curable resin composition deviate from the range of the present invention, the effect of the present invention is obtained in the coatability for forming a bead-shaped ejector and the like. It turned out that I couldn't get it.

The active energy ray-curable resin composition of the present invention is suitably used for forming a bead-shaped or dot-shaped sealing material or cushioning material by needle coating, and is optimal as a sealing material or cushioning material for a narrow space portion. This contributes to the miniaturization and cost reduction of electronic devices that incorporate it. Further, the cured product of the active energy ray-curable resin composition of the present invention has a large loss coefficient, is excellent in buffering property and vibration isolating property, and has low hardness, high flexibility, and low resilience. It can improve the impact resistance of equipment and contribute to the improvement of quality.

1 Bead-shaped sealant 10 Bead-shaped ejector 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 stand (stage)

Claims (5)

It contains a photopolymerizable oligomer (A), a photopolymerizable monomer (B), a photopolymerization initiator (C) and a thixotropy-imparting agent (D).
The photopolymerizable oligomer (A) is a urethane (meth) acrylate having an ether bond having a mass average molecular weight of 10,000 or more.
The photopolymerizable monomer (B) has the following formula (1) (in the formula, R ₁ represents a hydrogen atom or a methyl group, W represents an ethylene group or a propylene group, and n represents an integer of 1 to 4, respectively). The represented (meth) acryloyl compound (b1) is contained in an amount of 80% by mass or more of the total mass of the photopolymerizable monomer (B).

The photopolymerizable monomer (B) further has the following formula (2) (in the formula, R ₂ represents a hydrogen atom or a methyl group, Y represents an ethylene group or a propylene group, and m represents an integer of 1 to 20). Contains the (meth) acryloyl compound (b2) represented by

The content of the (meth) acryloyl compound (b2) represented by the formula (2) is the (meth) acryloyl compound (b1) represented by the formula (1) and the (meth) acryloyl represented by the formula (2). It is 0.1 to 5% by mass with respect to the total mass (b1 + b2) of the compound (b2).
The thixotropy-imparting agent (D) is silica fine particles and is
The total content (A + B) of the photopolymerizable oligomer (A) and the photopolymerizable monomer (B) is the photopolymerizable oligomer (A), the photopolymerizable monomer (B), and the photopolymerization initiator (the photopolymerization initiator). It is 94 to 99.99 mass% with respect to the total mass (A + B + C) of C).
The content of the photopolymerizable monomer (B) is 80 to 99% by mass with respect to the total mass (A + B) of the photopolymerizable oligomer (A) and the photopolymerizable monomer (B).
The thixotropy-imparting agent (D) is 3 to 15 based on 100 parts by mass of the total (A + B + C) of the photopolymerizable oligomer (A), the photopolymerizable monomer (B) and the photopolymerization initiator (C). Included by mass,
In the uncured state, the viscosity at a shear rate of 0.1 to 2s ^-1 is 10 to 5000 Pa · s, and the thixotropy coefficient in the range of a shear rate of 0.1 to 2s ^-1 is 1.1 to 10. An active energy ray-curable resin composition. The active energy ray-curable resin composition according to claim 1, wherein the silica fine particles, which are the thixotropy-imparting agent (D) , have a carbon content of less than 0.5% by mass. The active energy ray curing according to claim 1 or 2 , wherein the photopolymerization initiator (C) is composed of at least two or more kinds of compounds, and at least one kind is a phosphine-based compound or an aminoalkylphenon-based compound. Sex resin composition. A sealing material made of a cured product of the active energy ray-curable resin composition according to any one of claims 1 to 3 . A cushioning material made of a cured product of the active energy ray-curable resin composition according to any one of claims 1 to 3 .

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