JP2007051239A - Method for producing sealing material, sealing material and gasket using the same sealing material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a sealing material having excellent long-term preservation stability and affording a high-precision extrusion shape, to provide the sealing material obtained by the method for production and to provide a gasket using the sealing material. <P>SOLUTION: The method for producing the sealing material comprises the following steps when the sealing material comprising an energy ray curing liquid resin (A) and a thickening agent (B) is produced. a step (step 1) of stirring and mixing the component (A) with the component (B) using a mixer and a step (step 2) of aging (maturing) the resultant mixture liquid in a thermostatic chamber. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a method for producing a sealing material, and more particularly relates to a method for producing a sealing material that is excellent in long-term storage stability and obtains a highly accurate extruded shape, a sealing material, and a gasket using the sealing agent material. .

In recent years, as electronic devices have become smaller, higher performance and smaller size have progressed, and complex circuit configurations have been created. Even small amounts of dust can cause damage, so a gasket is used to prevent dust from entering. It is generally done.
As a method for manufacturing a gasket of a small electronic device, a method of injection molding a thermoplastic elastomer or the like, a method of punching a heat-resistant rubber sheet into a predetermined shape, and adhering the same have been adopted.
Recently, as a method for manufacturing gaskets for electronic devices, a dispensing method in which an energy beam curable solution resin is extruded using a dispenser, extruded into a gasket shape with a single stroke on the plate surface, and pasted is used. Since there is a merit that a process such as a process is unnecessary, it is widely used industrially.

On the other hand, along with downsizing of electronic devices, it is necessary to mold gaskets in a narrow range with a good dimensional system and high aspect ratio. In order to solve this problem, the gasket shape extruded from the dispenser was crushed by its own weight by adding an inorganic filler or an organic thickener to the energy ray curable solution resin and imparting thixotropy. In some cases, a device for improving the accuracy of the shape of the gasket has been proposed (see, for example, Patent Document 1).
Further, organic thickeners, particularly hydrogenated castor oil and amide wax, develop thixotropy by forming a network structure by swelling when applied with temperature in a dispersed state in the material. Usually, the material and the thixotropic agent are mixed in a mixer for a time required for swelling at a constant temperature. However, this swelling often takes time, and if time is taken to sufficiently swell during kneading, the productivity decreases, and when kneading is completed with insufficient swelling, the material increases with time. When this is used as a sealing material, there is a problem that the storage stability of the material is deteriorated and an extruded shape with high accuracy cannot be obtained.
Furthermore, coupled with the miniaturization of electronic equipment, there is a tendency for the demand for a sealing material that can obtain an extruded shape with high accuracy to be further increased.

JP 2003-007047 A

  The present invention provides a method for producing a sealing material that is excellent in long-term storage stability and provides a highly accurate extruded shape, a sealing material obtained by the production method, and a gasket using the sealing material. It is intended.

[式（Ｉ）中、Ｒ¹は（メタ）アクリロイル基およびビニル基の少なくともいずれかの不飽和基を含有するモノオール化合物の脱水酸基残基、Ｒ²は有機ジイソシアナート化合物の脱イソシアナート残基、Ｒ³は、数平均分子量1×１０³〜1×１０⁴で環状基または分岐鎖状基を含有するポリエステルジオール化合物の脱水酸基残基、数平均分子量1×１０³〜1×１０⁴のポリエーテルジオール化合物の脱水酸基残基、または脂肪族基含有ジオール化合物の脱水酸基残基、スチレンブタジエン共重合体含有ジオールの脱水酸基残基、または水添スチレンブタジエン共重合体含有ジオールの脱水酸基残基であり、Ａはジアミン化合物の脱水酸基残基またはジオール化合物の脱水素残基、ｐおよびｒの各々は０〜７、ｑは０〜３、ただし、ｑ＝０のとき、１≦ｐ＋ｒ≦１０である。]
で表され、かつ数平均分子量が５×１０³〜５×１０⁴である不飽和基含有ウレタンオリゴマーである上記（１）〜（４）のシーリング用材料の製造方法、
（６） 式（Ｉ）におけるＲ³が、環状基含有ジカルボン酸とジオールとが縮合した前記ポリエステルジオール化合物の脱水素残基、又は環状基含有ジカルボン酸無水物がジオールに反応して変性したポリエステルジオール化合物の脱水酸基残基である上記（５）のシーリング用材料の製造方法、
（７） 式（Ｉ）におけるＲ¹が、ヒドロキシアルキル（メタ）アクリレートおよびヒドロキシアルキルビニルエーテルのいずれかの前記モノオール化合物の脱水酸基残基である上記（５）に記載のシーリング用材料の製造方法、
（８） （Ａ）成分の不飽和基含有ウレタンオリゴマー（ただし、一般式（Ｉ）においてｑ＝０の場合）が、前記脂肪族基含有ジオール化合物、前記ポリエステルジオール化合物、または前記ポリエーテルジオール化合物と、前記有機ジイソシアナート化合物とを重付加反応させてイソシアナート基を両末端に有する付加物を形成した後、該イソシアナート基に、前記モノオール化合物を付加して得られるものである上記（５）〜（７）のシーリング用材料の製造方法、
（９） （Ａ）成分の不飽和基含有ウレタンオリゴマー（ただし、一般式（Ｉ）においてｑ≠０の場合）が、前記脂肪族基含有ジオール化合物、前記ポリエステルジオール化合物、または前記ポリエーテルジオール化合物と、前記有機ジイソシアナート化合物とを重付加反応させてイソシアナート基を両末端に有する付加物を形成した後、前記ジアミン化合物または前記ジオール化合物の末端の各々を、該付加物の片端のイソシアナート基に付加させ、該付加物の他の片端のイソシアナート基に、前記モノオール化合物を付加して得られるものである上記（１）〜（８）のシーリング用材料の製造方法、
（１０） （Ａ）成分１００質量部に対して、増粘剤（Ｂ）を０．５〜１０質量部を含有する上記（１）〜（９）のシーリング用材料の製造方法、
（１１） （Ｂ）成分としての増粘剤が、有機増粘剤である上記（１０）のシーリング用材料の製造方法、
（１２） 有機増粘剤が、水添ひまし油である上記（１１）のシーリング用材料の製造方法、
（１３） さらに、（Ｃ）成分として、重合開始剤、架橋剤、及びモノマーのうちの少なくとも一つを含有してなる上記（１）〜（１２）のシーリング用材料の製造方法、
（１４） 上記（１）〜（１３）のシーリング用材料の製造方法を用いて得られたシーリング用材料、及び
(１５) 請求項１４のシーリング用材料を用いたガスケット、 As a result of intensive studies to achieve the above object, the inventor conducted kneading and swelling at a specific temperature and time in the first step, and then controlled at a specific temperature in the second step. It has been found that the above-mentioned problems can be solved by performing curing (aging) for a specific time in a thermostatic chamber. The present invention has been completed based on such findings.
That is, the present invention
(1) A step of stirring and mixing the component (A) and the component (B) with a mixer in producing a sealing material containing the energy ray curable liquid resin (A) and the thickener (B) (step) 1) and a method for producing a sealing material comprising the step of aging (curing) the mixed solution in a thermostatic bath (step 2),
(2) The method for producing a sealing material according to the above (1), wherein the temperature range of stirring and mixing by the mixer in Step 1 is 30 to 120 ° C.
(3) In step 2, the aging temperature range is 40 to 100 ° C., and the aging is performed until the change rate after 8 hours of the viscosity (Pa · s) of the mixed solution at the aging temperature becomes 5% or less. A method for producing the sealing material according to (1),
(4) The method for producing the sealing material according to the above (1) to (3), wherein the liquid viscosity of the mixture after completion of the step 2 is ¹ to 100 Pa · s at 10 s-1
(5) The energy ray-curable liquid resin (A) is represented by the following general formula (I)

[In the formula (I), R ¹ is a hydroxyl group-removed residue of a monool compound containing at least ^one of a (meth) acryloyl group and a vinyl group, and R ² is a deisocyanate of an organic diisocyanate compound. Residue, R ³ is a dehydroxylated residue of a polyester diol compound having a number average molecular weight of 1 × 10 ³ to 1 × 10 ⁴ and containing a cyclic group or a branched chain group, and a number average molecular weight of 1 × 10 ³ to 1 × 10 Dehydroxylation residue of polyether diol compound ⁴ or dehydroxylation residue of aliphatic group-containing diol compound, dehydroxylation residue of styrene-butadiene copolymer-containing diol, or hydrogenated styrene-butadiene copolymer-containing diol A is a hydroxyl group residue, A is a dehydroxylation residue of a diamine compound or a dehydrogenation residue of a diol compound, each of p and r is 0 to 7, q is 0 to 3, provided that q = 0 ≦ p + a r ≦ 10. ]
And the method for producing a sealing material according to (1) to (4) above, which is an unsaturated group-containing urethane oligomer having a number average molecular weight of 5 × 10 ^{3 to} 5 × 10 ⁴ ,
(6) A polyester in which R ³ in formula (I) is a dehydrogenated residue of the polyester diol compound in which a cyclic group-containing dicarboxylic acid and a diol are condensed, or a cyclic group-containing dicarboxylic acid anhydride is modified by reacting with the diol. A process for producing a sealing material according to the above (5), which is a dehydroxylated residue of a diol compound;
(7) The method for producing a sealing material according to (5), wherein R ¹ in the formula (I) is a hydroxyl group-removed residue of the monool compound of any one of hydroxyalkyl (meth) acrylate and hydroxyalkyl vinyl ether ,
(8) The unsaturated group-containing urethane oligomer of component (A) (where q = 0 in the general formula (I)) is the aliphatic group-containing diol compound, the polyester diol compound, or the polyether diol compound. And an organic diisocyanate compound to form an adduct having an isocyanate group at both ends, and then the monool compound is added to the isocyanate group. (5) to (7) a method for producing a sealing material,
(9) The unsaturated group-containing urethane oligomer of the component (A) (provided that q ≠ 0 in the general formula (I)) is the aliphatic group-containing diol compound, the polyester diol compound, or the polyether diol compound. And an organic diisocyanate compound to form an adduct having isocyanate groups at both ends, and then each of the diamine compound or the diol compound ends is converted to an isocyanate at one end of the adduct. A method for producing a sealing material according to the above (1) to (8), which is obtained by adding to a narate group and adding the monool compound to an isocyanate group at the other end of the adduct,
(10) The method for producing a sealing material according to (1) to (9) above, containing 0.5 to 10 parts by mass of the thickener (B) with respect to 100 parts by mass of the component (A),
(11) The method for producing a sealing material according to (10), wherein the thickener as the component (B) is an organic thickener,
(12) The method for producing a sealing material according to (11), wherein the organic thickener is hydrogenated castor oil,
(13) Further, as the component (C), the method for producing a sealing material according to the above (1) to (12), which contains at least one of a polymerization initiator, a crosslinking agent, and a monomer,
(14) A sealing material obtained using the method for producing a sealing material according to (1) to (13) above, and
(15) A gasket using the sealing material according to claim 14,

ADVANTAGE OF THE INVENTION According to this invention, it is excellent in long-term storage stability and can provide the manufacturing method and sealing agent of the material for sealing which can control an extrusion shape with high precision.
Further, by using the sealing agent, a gasket having a narrow line width and a high height can be easily formed on the cover body. Therefore, it is suitably used for applications of a downsized gasket for electronic equipment.
Furthermore, the sealing agent by the manufacturing method of this invention can reduce the usage-amount of an organic thickener, and can reduce generation | occurrence | production of outgas (volatile organic compound).

The method for producing a sealing material according to the present invention stabilizes the value of the viscosity of the sealing material for 6 months at room temperature in order to suppress the thickening phenomenon over time during storage at room temperature and to reduce variations in the dispenser operation. It is necessary to be in the state. For that purpose, the step of stirring and mixing the energy ray-curable liquid resin (A) component and the thickener (B) component with a mixer (step 1) and the step of aging (curing) the mixed solution in a thermostatic bath It is necessary to have two steps (step 2).
The method for producing a sealing material of the present invention will be described with reference to FIGS. The vertical axis represents the viscosity (Pa · s) of the sealing material, the horizontal axis represents time (days), and a represents the preferred viscosity range.
FIG. 1 is a schematic diagram showing a change in viscosity of a sealing material according to a conventional example with time. Stir and mix the energy ray curable liquid resin (A) component and thickener (B) component with a mixer under a certain temperature condition, and stop when curve (1) reaches the desired viscosity (X). Used as a sealing agent.
However, when a dispenser is used, the viscosity increases during use because it is used while keeping the temperature warm, causing a deviation from the preferred range of the viscosity. When it is necessary to further shorten the time to reach (X), the thickener may be increased, but the variation due to the operation of the dispenser further increases.

FIG. 2 is a schematic diagram showing the change of the viscosity of the sealing material according to the embodiment of the present invention with time.
In the present invention, stirring and mixing of the component (A) and the component (B) by the mixer under a constant temperature condition are stopped at the (Y) point of the curve (2), and then the mixed solution is controlled to a constant temperature from the mixer. The viscosity is further increased by being transferred to a constant temperature bath and ripening, and may be appropriately determined depending on the combination of materials. Usually, aging for 1 to 7 days stabilizes the viscosity as shown in FIG. Even if a dispenser is used while keeping heat using this stable sealing material, there is almost no change in viscosity, and a stable operation can be performed.
In the case of FIG. 2, there is no particular limitation on the time until reaching (Y), and the viscosity is increased by mixing the components (A) and (B) uniformly except that the temperature for stirring and mixing is specified. If the thickener is swollen, it can be transferred to the next aging step.
In order to make a viscosity into a preferable range, it determines suitably by the kind of matrix which is (A) component, the kind and amount of (B) component, and the temperature conditions of the process 1 and the process 2.

If the conditions are met, the viscosity can be stabilized with almost the same curve only by stirring and mixing. However, the exclusive use of the mixer for this purpose for 1 to 7 days leads to a very high cost. .
Furthermore, in the production method of the present invention, in order to use the thickener most effectively and efficiently, the amount of the thickener used can be reduced, and the outgas derived from the thickener (volatile organic compound). The amount of can be reduced. It is desirable to reduce the amount of volatile organic compounds (VOC) to a negligible range from the viewpoint of avoiding the destruction of precision electronic equipment due to outgas and not deteriorating the environment of offices and houses.
From this viewpoint, the amount of gas generated when the cured sealing material is heated at a temperature of 150 ° C. for 20 minutes is preferably 500 ppm (mass basis) or less in terms of n-decane.
Therefore, if the amount of the thickener is reduced too much, the preferred viscosity range is not reached, and if it is too much, the viscosity rises.

The temperature range of stirring and mixing by the mixer in step 1 is usually 30 to 120 ° C, more preferably 50 to 100 ° C, although it may be appropriately determined depending on the solubility of component (A) and component (B). It is. The temperature range for aging in step 2 is 40-100.
° C is preferable, more preferably 50 to 90 ° C. In step 1, component (B) is completely dissolved at 50 to 120 ° C, and then gradually cooled to the aging temperature range in step 2 to develop viscosity. Create a structure to do. In step 2, the structure that develops the viscosity is grown. The setting of the temperature conditions in step 1 and step 2 is particularly important. By setting the temperature condition in the above temperature range, the thickener can swell efficiently, and a sealing material having a stable viscosity can be obtained.
The aging time in step 2 is preferably aging so that the change rate after 8 hours of the viscosity (Pa · s) of the mixed solution at the aging temperature is 5% or less.
Furthermore, it is preferable that the viscosity of the mixed solution after the completion of step 2 is ¹ to 100 Pa · s at 50 ° C. at a shear rate of 10 s ⁻¹ .

  As the energy ray-curable liquid resin (A) component, for example, a silicone-modified resin, a polysulfide resin, a polyurethane resin, or the like can be used. Among these, the following general formula (I)

[In the formula (I), R ¹ is a hydroxyl group-removed residue of a monool compound containing at least ^one of a (meth) acryloyl group and a vinyl group, and R ² is a deisocyanate of an organic diisocyanate compound. Residue, R ³ is a dehydroxylated residue of a polyester diol compound having a number average molecular weight of 1 × 10 ³ to 1 × 10 ⁴ and containing a cyclic group or a branched chain group, and a number average molecular weight of 1 × 10 ³ to 1 × 10 Dehydroxylation residue of polyether diol compound ⁴ or dehydroxylation residue of aliphatic group-containing diol compound, dehydroxylation residue of styrene-butadiene copolymer-containing diol, or hydrogenated styrene-butadiene copolymer-containing diol A is a hydroxyl group residue, A is a dehydroxylation residue of a diamine compound or a dehydrogenation residue of a diol compound, each of p and r is 0 to 7, q is 0 to 3, provided that q = 0 ≦ p + a r ≦ 10. ]
And an unsaturated group-containing urethane oligomer having a number average molecular weight of 5 × 10 ^{3 to} 5 × 10 ⁴ .

In the present invention, the unsaturated group-containing urethane oligomer (A) is represented by the general formula (I).
In general formula (I), R ¹ is a dehydroxylated residue of a monool compound containing an unsaturated group of at least ^one of a (meth) acryloyl group and a vinyl group.
Preferred examples of the monool compound include hydroxyalkyl (meth) acrylate and hydroxyalkyl vinyl. For example, diethylene glycol (meth) acrylate, dipropylene glycol (meth) acrylate, tripropylene glycol (meth) acrylate, triethylene glycol (meta ) Acrylate and polyethylene glycol (meth) acrylate. The (meth) acryloyl group refers to an acryloyl group or a methacryloyl group.

R ² is a deisocyanate residue of the organic diisocyanate compound. For example, alkylene groups such as methylene group, ethylene group, propylene group, butylene group and hexamethylene group, cycloalkylene groups such as cyclohexylene group, arylene groups such as phenylene group, tolylene group and naphthylene group, xylylene groups and the like are included. Here, the alkyl group may be linear, branched or cyclic. Organic diisocyanate compounds include isophorone diisocyanate, hexamethylene diisocyanate, norbornane diisocyanate, tolylene diisocyanate, xylene diisocyanate, trimethylhexamethylene diisocyanate, naphthalene diisocyanate, hydrogenated xylates. Preferred examples include range isocyanate, hydrogenated diphenylmethane diisocyanate and diphenylmethane diisocyanate.

R ³ is dehydroxylated residue of the polyester diol compounds with a number average molecular weight 1 × 10 ³ ~1 × 10 ⁴ containing a cyclic group or a branched chain group, the number-average molecular weight 1 × 10 ³ ~1 × 10 ⁴ Poly Dehydroxylation residue of ether diol compound, dehydroxylation residue of aliphatic group-containing diol compound, dehydroxylation residue of styrene butadiene copolymer-containing diol, or dehydroxylation residue of hydrogenated styrene butadiene copolymer-containing diol is there.
Among these, R ³ is a dehydrogenation residue of the polyester diol compound in which the cyclic group-containing dicarboxylic acid and the diol are condensed, and a dehydroxylation group in the polyester diol compound in which the cyclic group-containing dicarboxylic acid anhydride is modified by reacting with the diol. A residue, a dehydroxylated residue of a styrene butadiene copolymer-containing diol, or a dehydroxylated residue of a hydrogenated styrene butadiene copolymer-containing diol is preferred.
Examples of the cyclic group-containing dicarboxylic acid constituting R ³ or its acid anhydride include phthalic acid, phthalic anhydride, pyromellitic acid, pyromellitic anhydride, isophthalic acid, trimellitic acid, trimellitic anhydride, and tetrahydrophthalic acid. Tetrahydrophthalic anhydride, hexahydrophthalic acid, hexahydrophthalic anhydride and the like. Moreover, you may use these in mixture of multiple types.
Examples of the diol constituting R ³ include ethylene glycol, propylene glycol, 2,2,4-trimethyl-1,3-pentanediol, neopentyl glycol, 1,2-propanediol, 1,3-propanediol, 1, 4-propanediol, 1,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2,2-dimethyl-1,3-propanediol, bisphenol A, tetraethoxyxylate, 2,2 -Thiodiethanol, acetylene type diol, hydroxy-terminated polybutadiene, 1,4-cyclohexanedimethanol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-bis (2-hydroxyethoxy) cyclohexane, tri Methylene glycol, tetramethyle Glycol, pentamethylene glycol, hexamethylene glycol, decamethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, norbornylene glycol, 1,4-benzenedimethanol, 1,4-benzeneethanol, 2,4-dimethyl 2-ethylenehexane-1,3-diol, 2-butene-1,4-diol, 2,4-diethyl-1,5-pentanediol, 2-ethyl-2-butyl-1,3-propanediol, And 3-methyl-1,5-pentanediol.

In general formula (I), A is a dehydroxylated residue of a diamine compound or a dehydrogenated residue of a diol compound.
Such is not particularly limited, for example, diaminopropane, diaminobutane, nonanediamine, isophoronediamine, hexamethylenediamine, hydrogenated diphenylmethanediamine, bisaminopropyl ether, bisaminopropylethane, bisaminopropyldiethylene glycol Dehydroxylated residues of diamine compounds selected from ether, bisaminopropyl polyethylene glycol ether, bisaminopropoxyneopentyl glycol, diphenylmethane diamine, xylylene diamine, toluene diamine, and both terminal amino group-modified silicones, and ethylene glycol, propylene glycol , Polyethylene glycol, polypropylene glycol, butylene glycol, polytetramethylene glycol, penta Diol, hexane diol, are preferred dehydrogenation residue of a diol compound selected from the hydroxyl groups at both ends modified silicone, and a carboxyl group-containing diol.
R ¹ is preferably a dehydroxylated residue of a monool compound of either hydroxyalkyl (meth) acrylate or hydroxyalkyl vinyl ether. For example, R ¹ is a dehydroxylated residue such as hydroxyethyl acrylate or hydroxymethyl vinyl ether. Can be mentioned.
The urethane oligomer (A) can be preferably produced by the following method.

In general formula (I), when q = 0, the unsaturated group-containing urethane oligomer is the aliphatic group-containing diol compound, the polyester diol compound, the polyether diol compound, the styrene-butadiene copolymer diol, or the hydrogenated product. A styrene butadiene copolymer diol and the organic diisocyanate compound are subjected to a polyaddition reaction to form an adduct having an isocyanate group at both ends, and then the monool compound is added to the isocyanate group. Obtainable.
Further, the unsaturated group-containing urethane oligomer in the case of q ≠ 0 in the general formula (I) includes the aliphatic group-containing diol compound, the polyester diol compound, or the polyether diol compound, and the organic diisocyanate compound. To form an adduct having an isocyanate group at both ends, and then adding each of the diamine compound or the diol compound to the isocyanate group at one end of the adduct. It can be obtained by adding the monool compound to an isocyanate group at the other end of the other.
The number average molecular weight of the unsaturated group-containing urethane oligomer obtained as described above is preferably 5 × 10 ^{3 to} 5 × 10 ⁴ , but may exceed 5 × 10 ⁴ as long as the effects of the present invention are not impaired.

Next, the thickener as the component (B) added in the sealing material of the present invention is 0.1 to 10 parts by mass with respect to 100 parts by mass of the unsaturated group-containing urethane oligomer of the component (A). It is preferable to contain. When this thickener is used in combination with the specific urethane oligomer of component (A), thixotropy is effectively improved, and the extruded shape can be controlled with high accuracy. From this point, the addition amount of the component (B) is particularly preferably 1 to 5 parts by mass. A preferable amount of the thickener may be appropriately determined depending on the type of the component (B) and the matrix of the component (A).
As this thickener, both inorganic fillers and organic thickeners can be used. Only the organic thickener is heated and swollen in the component (A), and strong thixotropy is effectively obtained.
Examples of the inorganic filler include surface-treated fine silica of wet silica and dry silica, and natural minerals such as organic bentonite. Specifically, fine silica powder pulverized by a dry method [for example, product name: Aerosil 300 manufactured by Nippon Aerosil Co., Ltd.], fine powder obtained by modifying this fine silica powder with trimethyldisilazane [for example, Nippon Aerosil Product name: Aerosil RX300, etc.] and fine powder obtained by modifying the above silica fine powder with polydimethylsiloxane [for example, product name: Aerosil RY300, manufactured by Nippon Aerosil Co., Ltd.]. The average particle diameter of the inorganic filler is preferably 5 to 50 μm and more preferably 5 to 12 μm from the viewpoint of thickening.

Examples of the organic thickener include amide wax, hydrogenated castor oil, or a mixture thereof. Specifically, hydrogenated castor oil that is a hydrogenated product of castor oil (non-drying oil whose main component is ricinoleic acid) [for example, manufactured by Zude Chemie Catalysts Co., Ltd., trade name: ADVITOLL 100, manufactured by Enomoto Kasei Co., Ltd. Name: Disparon 305 etc.] and higher amide waxes that are compounds in which hydrogen of ammonia is substituted with an acyl group [for example, trade name: Disparon 6500, etc., manufactured by Enomoto Kasei Co., Ltd.].
Of these thickeners, organic thickeners are preferred. Natural mineral-based inorganic fillers cannot avoid impurities such as heavy metals, and surface-treated fine silica may change the wettability of the surface and change the viscosity of the composition, and depending on the type of surface treatment agent May generate harmful gas to the equipment during use.
Further, among organic thickeners, amide wax is particularly preferably hydrogenated castor oil because the presence of amine derived from the raw material may increase the crosslinking density and increase the hardness.

In the sealing material of the present invention, as the component (C), at least one of a photopolymerization initiator, a crosslinking agent, and a monomer can be added. These additions are particularly preferable when ultraviolet irradiation is performed.
The photopolymerization initiator may be either an intramolecular cleavage type or a hydrogen abstraction type. Examples of the intramolecular cleavage type include benzoin derivatives, benzyl ketals [for example, Ciba Specialty Chemicals Co., Ltd., trade name: Irgacure 651], α-hydroxyacetophenones [for example, Ciba Specialty Chemicals. Product name: Darocur 1173, Irgacure 184], α-aminoacetophenones [for example, Ciba Specialty Chemicals, Inc., product names: Irgacure 907, Irgacure 369], α-aminoacetophenones Examples thereof include combined use with thioxanthones (for example, isopropyl thioxanthone, diethyl thioxanthone), acylphosphine oxides [for example, trade name: Irgacure 819, manufactured by Ciba Specialty Chemicals Co., Ltd.], and the like. Examples of the hydrogen abstraction type include a combined use of benzophenones and an amine, and a combined use of thioxanthone and an amine. Further, an intramolecular cleavage type and a hydrogen abstraction type may be used in combination. Of these, oligomerized α-hydroxyacetophenone and acrylated benzophenones are preferred. More specifically, oligo [2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl] propanone] [for example, Lamberiti S.P.A, trade name: ESACURE KIP150, etc.], acrylic Examples thereof include benzophenone [for example, trade name: Ebecryl P136, manufactured by Daicel UCB Co., Ltd.], imide acrylate, and the like.

As the crosslinking agent, organic peroxides are preferably exemplified. Specifically, for example, 2,5-dimethyl-2,5-di (t-butylperoxy) -hexane; 2,5-dimethyl-2 , 5-di (benzoylperoxy) -hexane; t-butylperoxybenzoate; dicumyl peroxide; t-butylcumyl peroxide; diisopropylbenzohydroperoxide; 1,3-bis- (t-butylperoxy Isopropyl) -benzene; benzoyl peroxide; 1,1-di (t-butylperoxy) -3,3,5-trimethylcyclohexane and the like.
As the monomer, a (meth) acrylic acid ester monomer is preferable. The molecular weight of the monomer is preferably less than 1,000, and more preferably 150 to 600. (Meth) acrylic acid ester monomers include cyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, diethylene glycol monoethyl ether ( (Meth) acrylate, dimethylaminoethyl (meth) acrylate, dimethylol dicyclopentane di (meth) acrylate, dipropylene glycol (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, ethoxylated phenyl (meth) acrylate, ethyl (meth) Acrylate, isoamyl (meth) acrylate, isobornyl (meth) acrylate, isobutyl (meth) acrylate, isodecyl (meth) acrylate, isooctyl (Meth) acrylate, isostearyl (meth) acrylate, isomyristyl (meth) acrylate, lauroxypolyethylene glycol (meth) acrylate, lauryl (meth) acrylate, methoxydipropylene glycol (meth) acrylate, methoxytripropylene glycol (meth) Examples include acrylate, methoxypolyethylene glycol (meth) acrylate, and methoxytriethylene glycol acrylate. In addition, (meth) acrylate means an acrylate or a methacrylate.

Further, as other additives, additives such as a flame retardant, a stabilizer, a tackifier, and a colorant can be added within a range not impairing the effects of the present invention.
The manufacturing method of the composition for photocurable sealing materials of this invention is not specifically limited, A well-known method is applicable. For example, it can be manufactured by kneading using a single screw extruder, twin screw extruder, planetary mixer, twin screw mixer, high-shear mixer, etc., capable of adjusting the temperature.

  As the active energy rays used for curing the composition, ionizing radiation such as ultraviolet rays, electron beams, α rays, β rays, and γ rays is used. Examples of the ultraviolet light source include a xenon lamp, a low pressure mercury lamp, a high pressure mercury lamp, and an ultrahigh pressure mercury lamp. The atmosphere for irradiating with ultraviolet rays is preferably an inert gas atmosphere such as nitrogen gas or carbon dioxide gas or an atmosphere with a reduced oxygen concentration, but can be cured with ultraviolet rays even in a normal air atmosphere. The irradiation atmosphere temperature can usually be 10 to 200 ° C.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
1. <Viscosity Pa · s of sealing material>
A parallel plate was used in the viscoelasticity measuring apparatus, and measurement was performed at 50 ° C. and a shear rate of 10 S ⁻¹ for 20 seconds.
2. <Curing method of sealing agent>
A film having a thickness of 0.6 mm was formed and irradiated with energy rays to obtain a cured product. The energy ray, using a metal halide lamp, intensity of about 130 mJ / cm ² under air atmosphere, was irradiated under conditions of integrated quantity of light of about 8000 mJ / cm ^2. This cured product was further baked at 120 ° C. for 4 hours in an air atmosphere.
3. <Method for producing urethane oligomer>
400 g of a polyester diol compound (number average molecular weight 2000) obtained from 2,4-diethyl-1,5-pentanediol and phthalic anhydride, 82.4 g of norbornane diisocyanate, and di-t-butyl as an antioxidant -0.10 g of hydroxyphenol was added to a 1 liter four-necked flask equipped with a stirrer, a condenser, and a thermometer, and reacted at 80 ° C for 2 hours. Then, 46.2 g of 2-hydroxyethyl acrylate, 0.10 g of p-methoxyphenol as a polymerization inhibitor and 0.06 g of titanium tetra (2-ethyl-1-hexanolate) as an addition reaction catalyst were added, and the mixture was heated at 85 ° C. for 6 hours. Reacted. A part of the reaction solution was taken out and the absorption peak of the isocyanate group at 2280 cm ⁻¹ disappeared in the infrared absorption spectrum, whereby the end point of the reaction was confirmed, and the target urethane oligomer was obtained as the component (A). It was 18000 when the number average molecular weight was calculated | required by the polystyrene conversion value about the obtained urethane oligomer using the gel permeation chromatography.
4). <Preparation of sealing material>
100 parts by mass of the urethane oligomer obtained as described above, 25 parts by mass of a monomer (phenoxyethyl acrylate) and 2 parts by mass of a polymerization initiator (4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone) A mixture prepared by blending the parts was prepared in advance.

Example 1
Planetary by adding 2 parts by mass of ADVITOL 100 (trademark, manufactured by Zude Chemie Catalysts Co., Ltd., hydrogenated castor oil) as a thickening agent to 100 parts by mass of urethane oligomer contained in the mixture. Using a mixer, the temperature was set to 80 ° C. and stirred for 1 hour. Thereafter, stirring was performed while gradually cooling, and after confirming that the thickener was dispersed and the material temperature was 40 ° C., Step 1 was completed, and Step 2 was aged. After confirming that the viscosity change rate after 8 hours of the viscosity (Pa · s) of the mixture was 5% or less, Step 2 was completed. The viscosity after completion was 75 Pa · s at 50 ° C.
While the obtained sealing material was heated using a dispenser, it was extruded into a gasket shape by a single stroke on the surface of the extrusion plate, but the viscosity was stable, the line width was narrow and the height was high on the cover body. A highly accurate extruded shape that can be easily formed was obtained.
The amount of gas generated when the cured sealing material was heated at 120 ° C. for 10 minutes was 500 ppm (mass basis) or less in terms of n-decane.

ADVANTAGE OF THE INVENTION According to this invention, it is excellent in long-term storage stability and can provide the manufacturing method and sealing material of the material for sealing which can control an extrusion shape with high precision.
Further, by using the sealing agent, a gasket having a narrow line width and a high height can be easily formed on the cover body. Therefore, it is suitably used especially for the use of gaskets for small electronic devices.
Furthermore, the sealing agent by the manufacturing method of this invention can reduce the usage-amount of an organic thickener, and can reduce generation | occurrence | production of outgas (volatile organic compound).

It is a schematic diagram which shows the change by the time of the viscosity of the sealing material which shows a prior art example. It is a schematic diagram which shows the change with the time of the viscosity of the sealing material which shows the embodiment of this invention.

Claims (15)

  In the production of the sealing material containing the energy ray curable liquid resin (A) and the thickener (B), a step of stirring and mixing the components (A) and (B) with a mixer (step 1) and A method for producing a sealing material comprising a step (step 2) of aging (curing) the mixed solution in a thermostatic bath.   2. The method for producing a sealing material according to claim 1, wherein a temperature range of stirring and mixing by the mixer in Step 1 is 30 to 120 ° C. 3.   In the step 2, the aging temperature range is 40 to 100 ° C., and the aging is performed until the rate of change after 8 hours of the viscosity (Pa · s) of the mixed solution at the aging temperature becomes 5% or less. The manufacturing method of the sealing material as described. The method for producing a sealing material according to any one of claims 1 to 3, wherein the viscosity of the mixed solution 10 s ^-1 after completion of step 2 is ¹ to 100 Pa · s at 50 ° C. The energy ray-curable liquid resin (A) is represented by the following general formula (I)

[In the formula (I), R ¹ is a hydroxyl group-removed residue of a monool compound containing at least ^one of a (meth) acryloyl group and a vinyl group, and R ² is a deisocyanate of an organic diisocyanate compound. Residue, R ³ is a dehydroxylated residue of a polyester diol compound having a number average molecular weight of 1 × 10 ³ to 1 × 10 ⁴ and containing a cyclic group or a branched chain group, and a number average molecular weight of 1 × 10 ³ to 1 × 10 ⁴ Hydroxyl group residue of polyether diol compound, dehydroxyl group residue of aliphatic group-containing diol compound, dehydroxyl group residue of diol containing styrene butadiene copolymer, or dehydroxyl group of diol containing hydrogenated styrene butadiene copolymer A is a dehydroxylated residue of a diamine compound or a dehydrogenated residue of a diol compound, each of p and r is 0-7, q is 0-3, provided that q ≦ 0, 1 ≦ p A r ≦ 10. ]
The method for producing a sealing material according to claim 1, wherein the unsaturated group-containing urethane oligomer has a number average molecular weight of 5 × 10 ^{3 to} 5 × 10 ⁴ . R ³ in the formula (I) is a dehydrogenated residue of the polyester diol compound in which a cyclic group-containing dicarboxylic acid and a diol are condensed, or a polyester diol compound in which a cyclic group-containing dicarboxylic acid anhydride is modified by reacting with a diol. The method for producing a sealing material according to claim 5, which is a dehydroxylated residue. The method for producing a sealing material according to claim 4, wherein R ¹ in formula (I) is a hydroxyl group-removed residue of the monool compound of any one of hydroxyalkyl (meth) acrylate and hydroxyalkyl vinyl ether.   The unsaturated group-containing urethane oligomer of component (A) (provided that q = 0 in the general formula (I)) is the aliphatic group-containing diol compound, the polyester diol compound, or the polyether diol compound, 6. A product obtained by polyaddition reaction with an organic diisocyanate compound to form an adduct having an isocyanate group at both ends, and then adding the monool compound to the isocyanate group. 8. A method for producing a sealing material according to any one of 7 above.   The unsaturated group-containing urethane oligomer of component (A) (provided that q ≠ 0 in the general formula (I)) is the aliphatic group-containing diol compound, the polyester diol compound, or the polyether diol compound, After the polyaddition reaction with an organic diisocyanate compound to form an adduct having an isocyanate group at both ends, each of the diamine compound or the diol compound is converted into an isocyanate group at one end of the adduct. The method for producing a sealing material according to any one of claims 1 to 8, which is obtained by adding the monool compound to an isocyanate group at the other end of the adduct.   (A) The manufacturing method of the sealing material of Claims 1-9 containing 0.5-10 mass parts of thickeners (B) with respect to 100 mass parts of component.   The method for producing a sealing material according to claim 10, wherein the thickener as component (B) is an organic thickener.   The method for producing a sealing material according to claim 11, wherein the organic thickener is hydrogenated castor oil.   Furthermore, the manufacturing method of the material for sealing in any one of Claims 1-12 formed by containing at least one of a polymerization initiator, a crosslinking agent, and a monomer as (C) component.   The sealing material obtained using the manufacturing method of the sealing material in any one of Claims 1-13.   A gasket using the sealing material according to claim 14.

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