JP2001163931A - Photocurable sealant composition and member with sealing layer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photocurable sealant which gives by ultraviolet irradiation a cured product generating a suppressed amount of volatile gases, low water-absorptive and low hygroscopic and has excellent shape-retaining properties and an appropriate coating speed when applied on an adherend, thus permitting maintenance of mass productivity, cost reduction and high degree of freedom of design and ensuring stabilities (shape-retaining properties, surface smoothness and the like) of a cured sealing layer regardless of how the photocurable sealant applied on an adherend is photo-irradiated. SOLUTION: The photocurable sealant composition is mainly composed of (A) 10-80 wt.% of a urethane (meth)acrylate, (B) 20-90 wt.% of a (meth)acrylate monomer, (C) 0.3-10 wt.% of a photopolymerization initiator and (D) 1-30 wt.% of a filler and has a yield value in shear stress of 5-100 Pa.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photocurable sealant composition, and a method for forming a seal layer using the composition, and more particularly to a method for sealing an electronic component case containing an electronic circuit element or an electronic component. And a method for forming a sealing layer therefor.

[0002]

2. Description of the Related Art Conventionally known photocurable resin compositions include unsaturated polyester resins, epoxy (meth) acrylates, urethane (meth) acrylates, and the like.
A resin obtained by adding a photopolymerization initiator to an acrylate resin represented by a (meth) acrylate monomer or the like, or a resin obtained by adding a photopolymerization initiator to an epoxy resin is used. In particular, it is known that those using urethane (meth) acrylate can be used for various uses because they easily impart flexibility to the cured product. (Patent No. 260
0563)

[0003] These photocurable resin compositions are rapidly cured by irradiating light such as ultraviolet rays. However, these cured products have a low molecular weight even if the light irradiation is complete. There remains a problem that the low molecular weight compound volatilizes from the cured product. It is considered that this is caused by a low-molecular-weight unreacted substance or unreacted substance, an unreacted photopolymerization initiator, a product from a photopolymerization initiator decomposed or isomerized by light, and the like.

On the other hand, there is a great demand and demand for photocurable resins in the electric and electronic fields, but in the field of advanced technologies such as high-precision parts and recording media, low-molecular-weight compounds derived from the above-mentioned cured products are not used. The occurrence causes corrosion and malfunction. Also, when using a photocurable resin as a sealant or adhesive for a magnetic hard disk drive, dust or contaminants due to defective sealants may invade, or corrosive or contaminants generated from the cured product, A malfunction occurs when recording or reading a signal (Japanese Patent Laid-Open No. 6-105502, Japanese Patent Laid-Open No. 8-72189, Japanese Patent Laid-Open No. 8-74863, etc.). In addition, there is a concern that a catalyst used in synthesizing the photocurable resin may bleed out impurities (for example, an organic tin compound) and adversely affect the magnetic hard disk drive. further,
In order to use such a photocurable resin as a sealing material, it is also required that the cured product has low water absorbency and low moisture absorbency and excellent water resistance.

[0005]

In order to solve such a problem, the applicant of the present invention has previously disclosed Japanese Patent Application Laid-Open No. 6-16 / 1994.
749, JP-A-7-33837, and Japanese Patent Application No. 10-9108.
0 proposes a photocurable resin composition in which generation of volatile gas and bleeding out of impurities are suppressed. Although these inventions are excellent in terms of suppressing volatile gas from the cured product and bleeding out impurities, the cured product has poor water resistance and high water absorption and moisture absorption, and has a photocurable property to the adherend. There was a problem that the shape retention property when the composition was applied, that is, the thickness as a sealing material could not be secured due to the flow over time after application.

[0006] The above-mentioned shape retention can be solved to some extent by photo-curing immediately after application of the photo-curable resin composition.
If the application distance of the sealant is long or the application takes a long time, the height of the seal layer differs between the application start position and the application end position, resulting in an uneven seal layer. Further, when the surface to be coated is not horizontal, the tendency is more remarkable. Therefore, it is conceivable to operate the ultraviolet lamp so as to follow the trajectory of the applied photocurable resin and to irradiate and cure the ultraviolet rays.However, in this case, the application irradiation apparatus becomes large-scale and leads to an increase in cost. Wrinkles are formed on the surface of the cured product of the photocurable resin, making it difficult to obtain a smooth seal layer.

Therefore, an object of the present invention is to solve the above-mentioned problems, that is, to suppress generation of volatile gas from a cured product cured by irradiation with ultraviolet rays, to reduce water absorption and moisture absorption, and It has high shape retention when applied to a surface, maintains mass productivity by having an appropriate application speed, reduces costs and gives design freedom, and has a photocurable seal applied to an adherend. It is an object of the present invention to provide a photocurable sealant capable of securing the stability (shape retention and surface smoothness, etc.) of a cured seal layer regardless of the method of irradiating light to the agent, and a member to which the seal layer is attached. Aim.

[0008]

In order to solve the above-mentioned problems, (A) urethane (meth) acrylate 10 to 80% by weight (B) (meth) acrylate monomer 20 to 90%
(C) Photopolymerization initiator 0.3 to 10% by weight (D) Filler 1 to 30% by weight A composition containing the above (A) to (D) as a main component, and this composition is Shear stress
s) A photocurable sealant composition having a yield value in the range of 5 to 100 Pa (Pascal) was obtained. In addition, a member with a seal layer was cured by light irradiation so that the cross-sectional shape of the seal layer formed from the composition became 0.5 to 0.9 with respect to the width of 1.

The urethane (meth) acrylate (A) which can be used in the present invention includes polycarbonate-based urethane (meth) acrylates disclosed in JP-A-5-70535 and JP-A-6-301206. Urethane (meth) acrylate obtained by adding ethyl isocyanate (meth) acrylate to an alcohol obtained by chain-extending bisphenol A with polyethylene glycol or the like, or (meth) acrylate-modified perfluoropoly as disclosed in JP-A-10-237392 Examples include ether urethane prepolymers and urethane (meth) acrylates obtained by adding a (meth) acrylate having an active hydrogen group to a reaction product of a polyether polyol or a polyether diol with an organic diisocyanate compound. Among these, a urethane prepolymer obtained by mixing and reacting a polyether polyol or a polyether diol with an organic diisocyanate compound in a molar ratio of 1: 1 to 1: 2 in a diluent, and further comprising the urethane prepolymer The remaining isocyanate groups of the polymer have a sufficient amount of active hydrogen groups to react therewith (meth)
Compounds obtained by reacting acrylate monomers are preferred. In addition, specific examples of the polyether polyol and the polyether diol are described in Japanese Patent No. 2568.
Bisphenol A in the molecule as described in US Pat.
Examples thereof include a polyol compound or a diol compound having a skeleton and having a hydroxyl group at a terminal or a side chain, and a polyol compound or a diol compound having an ethylene oxide or propylene oxide structure in a molecule. These polyether polyols and polyether diols are used alone or in combination of two or more. Also,
Among these compounds, a polyether polyol compound or a polyether diol compound having a bisphenol A skeleton and an ethylene oxide structure in the molecule is particularly preferable from the viewpoint of photocurability, water absorption, and outgassing.

As the organic diisocyanate compound, for example, diphenylmethane diisocyanate (MD
I), tolylene diisocyanate (TDI), xylene diisocyanate (XDI), isophorone diisocyanate (IPDI), naphthylene diisocyanate (ND
I), tolidine diisocyanate (TPDI), hexamethylene diisocyanate (HDI), dicyclohexylmethane diisocyanate (HMDI), trimethylhexamethylene diisocyanate (TMHDI) and the like, and these may be used alone or in combination of two or more. Among them, hexamethylene diisocyanate (HDI), dicyclohexylmethane diisocyanate (HMDI),
Trimethylhexamethylene diisocyanate (TMHD
I) is preferred.

The (meth) acrylate monomers having an active hydrogen group include, for example, ethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol and polyethylene glycol. Mono (meth) acrylates or di (meth) acrylates of trihydric alcohols such as dihydric alcohols such as trimethylolethane, trimethylolpropane, and glycerin. Seeds can be mixed and used.

The urethane (meth) acrylate (A) obtained as described above has an average molecular weight of MW of 1,000.
It is preferably 0 to 100,000, and
It is particularly preferred that it is in the range of 000 to 50,000. If the average molecular weight exceeds 100,000 in MW, the viscosity is too high, so that application by a coating machine becomes difficult and workability deteriorates. If it is less than 1,000, the cured product becomes hard and lacks flexibility.

The polymerization catalyst used for synthesizing the urethane (meth) acrylate (A) is not particularly limited as long as it is conventionally known. In consideration of the occurrence of bleeding and bleed-out of impurities, an organic zinc or amine compound is preferred. Specific examples of the organic zinc include zinc salt compounds of carboxylic acids such as zinc octenoate and zinc 2-ethylcaproate, and triethylamine, dimethylcyclohexylamine, tetramethylethylenediamine, pentamethyldiethylenetriamine, pentamethyldipropylenediamine, and tetramethylguanidine. , Triethylenediamine, N-methylmorpholine, 1,2-dimethylimidazole, dimethylaminoethanol, dimethylaminoethoxyethanol, trimethylaminoethylethanolamine, (2-hydroxyethyl) morpholineetheramine, N-methylpiperazine, N, N ' Amine compounds such as -dimethylpiperazine and N-endoethylenepiperazine.

The (B) (meth) acrylate monomer that can be used in the present invention is a (meth) acrylate monomer having at least one cyclic structure in the molecule, and specifically, for example, isobornyl (meth) acrylate ) Acrylate, cyclohexyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, phenoxy (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, Dicyclopentadiene di (meth) acrylate and the like are preferable, and phenoxy (meth) acrylate and tetrahydrofurfuryl (meth) acrylate are preferable, and while having low water absorption, high reactivity, or having a cyclic structure, Gala Phenoxy and the like transition (TG) point is low (meth) acrylate are particularly preferred. Also,
It is desirable that the molecular weight of these (meth) acrylate monomers be 1000 or less.

Examples of the photopolymerization initiator (C) that can be used in the present invention include acetophenone, diethoxyacetophenone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1, benzoin and benzoin. Examples include, but are not limited to, ethyl ether, benzyldimethyl ketal, benzophenone, benzyl, methylbenzoyl formate, thioxanthone, diethylthioxanthone, and conventionally known photopolymerization initiators can be used. In particular, 2-hydroxy-2-methyl-1-phenylpropan-1-one (trade name: DAROCURE) as exemplified in JP-A-7-33837
1173 Ciba Geigy), 4- (2-
(Hydroxyethoxy) phenyl- (2-hydroxy-2
-Propyl) ketone (trade name IRGACURE 29)
59 Ciba Geigy), 4- (2-acryloyloxyethoxy) phenyl- (2-hydroxy-
2-propyl) ketone, 1-hydroxycyclohexyl-phenyl ketone (trade name: IRGACURE 184)
Ciba Geigy), 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropane-1
-One, 1- (4-dodecylphenyl) -2-hydroxy-2-methylpropan-1-one, 2-methyl-2-
Morpholino (4-thiomethylphenyl) propane-1-
ON (Product name IRGACURE 907 Ciba G
eigy), 2-benzyl-2-dimethylamino-
1- (4-morpholinophenyl) -butanone (trade name
IRGACURE 369 Ciba Geigy), 2-hydroxy-2-methyl-1- [4- (1-
Methylvinyl) phenyl] propane oligomer (trade name: ESACURE KIP 150 Lambert)
is used as a photopolymerization initiator,
Generation of volatile gas can be suppressed, and in particular, 2-hydroxy-2-methyl-1- [4- (1-methylvinyl)
An oligomer of [phenyl] propane is particularly preferred because of its large effect.

As the filler (D) that can be used in the present invention, an inorganic filler such as silica powder can be preferably used. As the fine powder silica, the average primary particle diameter is 1 to 100.
in hydrolyzing finely divided silica, preferably 5 to 50 nm, in silicon oxychloride in an oxyhydrogen flame,
Fine powdered silica such as alumina-containing silica, titanium oxide-containing silica, iron oxide-containing silica and the like can be used in the presence of chlorides such as titanium chloride, aluminum chloride, and iron chloride. Those that have been used are preferably used.

Hydrophobic finely divided silica is prepared by coating the surface of ordinary hydrophilic finely divided silica with an alkyl, aryl, aralkyl-based silane coupling agent having a hydrophobic group such as n-octyl trialkoxysilane, dimethyldichlorosilane, hexamethyldisilazane. Or a silylating agent such as polydimethylsiloxane having a hydroxyl group at a terminal, or a higher alcohol such as stearyl alcohol, or a higher fatty acid such as stearic acid, and specifically obtained as follows. Commercial products can be used. 1) A treated as dimethyldichlorosilane
EROSIL-R972, R974, R976 (all manufactured by Nippon Aerosil Co., Ltd.) 2) A as hexamethyldisilazane-treated
EROSIL-RX50, NAX50, NX90, RX
200, RX300 (all manufactured by Nippon Aerosil Co., Ltd.) 3) AEROS treated with octylsilane
IL-R805 (all manufactured by Nippon Aerosil Co., Ltd.) 4) AEROSIL-RY50, NY50, RY200S,
R202, RY200, RY300 (all manufactured by Nippon Aerosil Co., Ltd.), CAB ASIL TS-720 (CABO
(Manufactured by T Company) In addition, several companies also sell hydrophobic fine powdered silica that has been subjected to the same treatment. This finely divided silica may be used alone or in combination of two or more. Among these, the use of silica powder surface-treated with polydimethylsiloxane is particularly preferable because the photocurable sealant composition of the present invention can be imparted with appropriate thixotropic properties and viscosity, that is, ease of application and shape retention.

The mixing ratio of the above-mentioned components (A) to (D) is (A) 10 to 80% by weight, preferably 20 to 60% by weight of urethane (meth) acrylate, and (B) (meth) acrylate. 20 to 90% by weight of a monomer, preferably 40 to 80% by weight, and (C) a photoinitiator of 0.3 to 10%.
Wt%, (D) 1 to 30 wt% filler, preferably 3 to
Desirably, it is 20% by weight.

If the amount of the urethane (meth) acrylate (A) is more than 80% by weight, the composition becomes too high in viscosity, making it difficult to apply by a coating machine and reducing workability.
If it is less than 0% by weight, the cured product becomes hard and lacks flexibility. (B) If the amount of the (meth) acrylic acid ester monomer is more than 90% by weight, the cured product becomes hard and lacks flexibility. If the amount is less than 20% by weight, the composition becomes too high in viscosity and cannot be applied by a coating machine. It becomes difficult and workability worsens.
(C) If the amount of the photopolymerization initiator is more than 10% by weight, the storage stability of the composition is reduced, the physical properties of the cured product are reduced, or the generation of outgas is increased. Also, 0.
If it is less than 3% by weight, the photocurability will be reduced. (D) If the amount of the filler exceeds 30 parts by weight, the composition may have too high a viscosity to be applied by an applicator, or the applied sealant may lose its surface smoothness. If the amount is less than 1 part by weight, the shape retention of the sealant when applied is reduced, and the sealant tends to flow. Therefore, it is difficult to form a thick seal layer.

The photocurable sealant composition of the present invention can be produced by mixing the above-mentioned components (A) to (D) by an ordinary method. It is preferable to perform stirring, and it is desirable to perform stirring in a vacuum so as not to trap air bubbles.

The photocurable sealant composition of the present invention is applied to a flange portion of an adherend such as an electronic component, and then cured by irradiation with light, whereby the cured product forms a seal layer having rubber elasticity. This functions as a sealing material. In this case, it is firmly bonded to the flange portion of the adherend, so that it can be used not only as a sealing material but also as an adhesive or a surface coating agent. Especially metal, plastic, glass,
Alternatively, it can be adhered to many materials such as an adherend coated with these materials, and among them, the adhesiveness to a metal or a metal-plated material is good.

The photocurable sealant composition of the present invention is used as a member having a rubber elastic seal layer by being applied to the flange surface of a member requiring sealing and photocuring. Although it is particularly suitable, this is because the photocurable sealant composition of the present invention has a moderate viscosity and thixotropic property, that is, the application stability (quantitative and shape) of the sealant when applied to the flange portion. Target) and excellent shape maintaining properties for maintaining the shape as applied until light curing. After applying the photocurable sealant composition to the adherend, a small amount of light may be applied to cure the composition to a semi-gelled state to improve shape retention. Further, the photocurable sealant composition of the present invention is most effective for light containing an ultraviolet region emitted from a conventionally known light source, for example, a mercury lamp, a xenon lamp, etc., but has, for example, an absorption wavelength for visible light. If a photopolymerization initiator is used, curing by visible light is also possible.

As the coating device that can be used in the present invention, a conventionally known automatic coating device can be used. These automatic coating devices include a robot unit having a three-dimensionally movable arm unit, a nozzle unit that discharges a material fixed to the arm unit, a material supply unit that supplies a material to the nozzle unit, Generally comprises a control unit for controlling the In order to apply the photocurable sealant composition of the present invention using such an automatic application apparatus, the inner diameter of the nozzle for discharging the material is 0.1 to 2.0 mm (preferably 0.5 to 1. 2m
m), the discharge pressure is 0.001 to 0.05
MPa (preferably 0.005 to 0.5 MPa).
02 MPa), and the coating speed is 1 to 100 mm / sec.
(Preferably 10 to 30 mm / sec). At this time, it is desirable that the height / width ratio of the seal layer applied to the adherend is 0.5 or more with respect to the width 1. By using such a coating device, for example, a seal layer having a coating width of about 2.0 mm or less suitable for hermetic sealing of a magnetic recording device (hard disk) can be easily formed.

Further, the photocurable sealant composition of the present invention has a shear stress of 1 to 100.
It is desirable to have a yield value (yield stress) in the range of Pa (Pascal). By performing such a limitation, the photocurable sealant composition of the present invention starts flowing (applying) at a relatively low discharge pressure (shear stress), and after removing the discharge pressure, immediately returns to its original state. (Specific viscosity or thixotropy) and loses fluidity. This characteristic (viscoelasticity) can be shown in Tables 4 to 8 in another expression.

This shear stress (Shear stress)
s) and the measurement of stress yield value, etc., are described in the stress-controlled rheometer DAR-100 (Rheological (REO)
LOGICA). In this measuring apparatus, a sample (photocurable sealing agent composition) is sandwiched between two plates (A, B) using a measuring jig as shown in FIG. The viscoelasticity (rheology) of the sample is measured by applying an external force. The measurement conditions at this time are as follows: the movable plate A shown in FIG.
(Diameter 25 mm) and gap 1.0 between fixed plate B
mm, and after the sample is filled therein, the external force in the rotational direction with respect to the axis of the movable plate A is varied (variable angular velocity, temperature 2
5 ° C., frequency 0.0016 Hz to 16.0 Hz).

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to embodiments. The following examples show only one embodiment of the present invention, and the present invention is not limited thereto.

Synthesis of Urethane (meth) acrylate Synthesis Example 1: Hexamethylene diisocyanate (HD) was added to 1.9 mol of polyether diol represented by the structural formula (1).
I) 2.0 mol of butylhydroxytoluene (0.4% by weight, based on the total weight of the mixture of BHT polyether diol and HDI) as polymerization inhibitor and tetrahydrofurfuryl acrylate (polyether diol) as diluent And HDI in a total weight ratio of 20% by weight), and 0.01% by weight of octyl zinc was added as a catalyst to the mixture, and the mixture was reacted at 80 ° C. for 2 hours to obtain a terminal. To obtain a prepolymer having an isocyanate group. Then, 2-hydroxyacrylate (2
-HEA) was added at 4.0 mol, and the mixture was stirred at 80 ° C for 2 hours to synthesize a urethane (meth) acrylate having an acryloyl group at a terminal. The average molecular weight of the urethane prepolymer was determined to be approximately MW 50,000 by GPC.
0 and the degree of dispersion was 3.0.

[0028]

Embedded image n represents an integer of 1 to 5, and Ph represents a benzene ring.

Synthesis Example 2: 4.0 mol of hexamethylene diisocyanate (HDI) was added to 3.0 mol of the polyether diol used in Synthesis Example 1, and butyl hydroxytoluene (BHT polyether diol and HD was used as a polymerization inhibitor).
I) in the presence of 0.4% by weight based on the total weight of the mixture of I) and tetrahydrofurfuryl acrylate (20% by weight based on the total weight of the mixture of polyether diol and HDI) as a diluent. 0.01 for the mixture
Wt% octylzinc is added as a catalyst,
The reaction was carried out for an hour to obtain a prepolymer having an isocyanate group at a terminal. Next, 4.0 mol of 2-hydroxyacrylate (2-HEA) was added, and the mixture was stirred at 80 ° C. for 2 hours, and urethane (meth) having an acryloyl group at a terminal was added.
Acrylate was synthesized. The average molecular weight of this urethane prepolymer was approximately MW 8,0
00 and the degree of dispersion was 1.7.

[0030]

Examples 1 to 8 Photocurable sealant compositions were produced at the compounding ratios shown in Table 1, and the produced compositions were evaluated based on the following evaluation test methods. Table 1 shows the results.

Each evaluation test was measured by the following method. 1. Outgas test: 1 g of the cured product was stored in a high-temperature bath at 80 ° C. for 24 hours, and the change in weight was measured. 2. Water absorption test: 1 g of the cured product was immersed in boiling water at 100 ° C. for 2 hours, and the water absorption was measured. 3. Coatability test: Using a TSR-50 type automatic coater (manufactured by ThreeBond Co., Ltd.), the inner diameter of the nozzle is 1.0 mm, and the pressure is 0.
01 to 0.015 MPa, nozzle moving speed 20 mm / s
The applicability when applied under the conditions of ec was visually checked. 4. Shape retention: After leaving the photocurable sealant composition applied to the adherend by the applicator of 3 above at 25 ° C. × 2 h, photocured to measure the height / width of the cured product (seal layer). did. 5. Surface smoothness after curing: The surface smoothness after photocuring of the photocurable sealant composition (25 ° C. × 1 h) applied to the adherend in 4 above was visually confirmed. 6. Rubber physical properties of cured product: The rubber elasticity of the cured product of the above 5 was confirmed by finger touch. 7. Storage test: The condition after storage of the compounded photocurable sealant composition at room temperature for one week was observed.

[0032]

[Table 1] * 1 The urethane acrylates of Synthesis Examples 1 and 2 contain 20% by weight of tetrahydrofurfuryl acrylate. * 2 Polyester urethane acrylate manufactured by Negami Industry Co., Ltd. * 3 Photopolymerization initiator manufactured by Lamberti * 4 Photopolymerization initiator manufactured by Ciba Geigy

According to the results shown in Table 1, outgassing of polyether urethane acrylate can be suppressed more than that of polyester urethane acrylate. When a high molecular weight photopolymerization initiator is used, outgassing can be further reduced. Polyether urethane acrylate having an average molecular weight of 50,000 has a higher viscosity than that having an average molecular weight of 8,000, so that the coating amount decreases under the same coating conditions. In other words, the coating speed becomes slow, and it is necessary to increase the discharge pressure to secure the same coating amount.

[0034]

Examples 9 to 14, Comparative Examples 1 and 2 Photocurable sealant compositions were produced at the compounding ratios shown in Table 2, and the produced compositions were evaluated based on the following evaluation test methods. .
Table 2 shows the results.

[0035]

[Table 2] -Represents unmeasured.

According to the results in Table 2, it is found that the use of a (meth) acrylate monomer having at least one or more cyclic structures in the molecule gives favorable results in outgassing properties and water absorption.

[0037]

Examples 15 to 19, Comparative Examples 3 and 4 Photocurable sealant compositions were produced at the compounding ratios shown in Table 3, and the produced compositions were evaluated based on the following evaluation test methods. . Table 3 shows the results.

[0038]

[Table 3] * 1 Liquid dripping occurs from the nozzle tip. * 2 The viscosity is too high to apply. * 3 Viscosity increased three times or more of the initial level. -Represents unmeasured.

According to the results shown in Table 3, the hydrophobically treated silica powder has good shape retention and storage properties, and the one treated with polydimethylsiloxane is particularly excellent in shape retention.

The results of measuring the viscoelasticity of the compositions of Examples 15 and 16 are shown in Tables 4 to 8. At the time of measurement, the compositions of Examples 15 and 16 were subjected to the stress control type rheometer DAR-100 type (REOLO
GICA), and 10 (1/1) for 60 seconds.
After stirring in s), the mixture was allowed to stand for 100 seconds and immediately measured. Detailed conditions are as follows. Street: 13 points were measured at 0.0016 to 16 Hz. Continuous on Strain 1.00
E-3 Time 1179.3s

[0041]

[Table 4] In the table, the dot ● represents the composition of Example 15 and the dot ○ represents the composition of Example 16.
Each represents a composition.

Table 4 shows the shear stress.
3 is a graph showing the relationship between storage elastic modulus (G'kPa) and storage elastic modulus (G'kPa). The composition of Example 16 has a stable storage modulus over a wider range of shear stress.

[0043]

[Table 5] In the table, the point を indicates the composition of Example 15, and the point □ indicates the composition of Example 16.
Respectively.

Table 5 shows the shear stress (Shear stress).
FIG. 5 is a graph showing the relationship between ss Pa) and viscosity.
It can be seen that the composition No. 6 has a yield value (yield stress) around 50 Pa.

[0045]

[Table 6] The dot indicates the composition of Example 15, and the dot indicates the composition of Example 16.

Table 6 shows the angular velocity (Omega rad / s).
And a graph showing the relationship between storage elastic modulus (G'kPa),
In particular, the composition of Example 16 was found to be excellent in stability at the time of application since the value of the storage modulus was stable at around 1.

[0047]

[Table 7] The dot indicates the composition of Example 15, and the dot indicates the composition of Example 16.

Table 7 shows the angular velocity (Omega rad / s).
Is a graph showing the relationship between the loss tangent (Tan phase) and the loss tangent (Tan phase).
Since the loss tangent was lower than that of the composition of Example 15 in the range of (ad / s), it was found that the loss tangent was closer to a non-fluid, and thus the shape retention was high.

[0049]

[Table 8] The dot indicates the composition of Example 15, and the dot indicates the composition of Example 16.

Table 8 shows the angular velocity (Omega rad / s).
In a graph showing the relationship between the viscosity and the viscosity, it can be seen that the viscosity decreases as the angular velocity increases.

[0051]

According to the photocurable sealant composition of the present invention, outgassing and impurities are not generated from the cured product and the influence on the surroundings is small. Especially polyether urethane (meta)
The effect is remarkable in a system using an acrylate or a system using a high molecular weight photopolymerization initiator.

The use of the silica powder which has been subjected to the hydrophobic treatment provides a composition having a higher shape retention, and the height / width ratio of the seal layer can be kept high, so that the effect as a sealant is greater. In particular, the effect of silica powder treated with polydimethyl silicone oil is remarkable. Furthermore, because it has properties (viscoelasticity) suitable for application using an automatic applicator, it can be applied without being affected by the shape and size of the adherend, so the design of the adherend is free. The degree increases.

After the photocurable sealant composition of the present invention is applied to an adherend, it does not easily shift or flow without being cured by light irradiation, so that it can be easily moved, and thus can be easily moved. High productivity because the process can be processed in a lump.

[Brief description of the drawings]

FIG. 1 is a partially enlarged view of an apparatus used for measuring a shear stress.

[Explanation of symbols]

 1 Photocurable sealant composition (uncured) A Movable plate B Fixed plate

Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat II (reference) C09J 7/02 C09J 7/02 Z 4J040 C09K 3/10 C09K 3/10 DF term (reference) 4H017 AA27 AA31 AA39 AC08 AC16 AC19 AD06 AE05 4J004 AA01 AA14 AA17 AB07 FA05 4J011 QA03 QB24 SA01 SA21 SA31 SA41 SA51 SA64 SA78 UA01 VA01 WA01 WA06 4J027 AG13 AG14 AG15 AG23 AG24 AJ01 BA07 BA08 BA11 CA18 CB04 CC04 CC05 CD06 4J0138 FA111 FA141 FA KA03 KA08 KA20 MA14 PA17 PB09 PB12 4J040 FA151 FA152 FA161 FA162 FA171 FA172 FA291 FA292 HA306 HB13 HB19 HD19 JB08 KA07 KA13 KA42 LA06 LA07

Claims (9)

[Claims] (A) Urethane (meth) acrylate 1
(B) (meth) acrylate monomer 20 to 90% by weight
(C) Photopolymerization initiator 0.3 to 10% by weight (D) Filler 1 to 30% by weight A composition containing the above (A) to (D) as a main component, and this composition is Shear stress
s) A photocurable sealant composition having a yield value (yield stress) in the range of 5 to 100 Pa (Pascal). 2. The (A) urethane (meth) acrylate has a hydroxyl group in a molecule thereof, in addition to a reaction product of a polyether diol or a polyether polyol or a mixture thereof and an organic diisocyanate compound. The photocurable sealant composition according to claim 1, which is a polyether urethane (meth) acrylate compound obtained by polymerizing an acrylate monomer. 3. The photocurable sealant composition according to claim 2, wherein the polyether diol, the polyether polyol, or a mixture thereof has a bisphenol skeleton in a molecule. 4. The photocurable sealant composition according to claim 1, wherein the urethane (meth) acrylate (A) has an average molecular weight of 1,000 to 100,000. 5. The photocurable sealant composition according to claim 1, wherein the (B) (meth) acrylate monomer has at least one cyclic structure in its molecular structure. 6. The photocurable sealant according to claim 1, wherein the (B) (meth) acrylate monomer has a molecular weight of less than 1,000. 7. The photocurable seal according to claim 1, wherein the photopolymerization initiator (C) is an oligomer of 2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl] propane. Agent. 8. The photocurable sealant according to claim 1, wherein the filler (D) is obtained by subjecting a surface of silica powder to a hydrophobic treatment. 9. (A) Urethane (meth) acrylate 1
(B) (meth) acrylate monomer 20 to 90% by weight
(C) Photopolymerization initiator 0.3 to 10% by weight (D) Filler 1 to 30% by weight A composition containing the above (A) to (D) as a main component, and this composition is Shear stress
s) A photocurable sealant having a yield value in the range of 5 to 100 Pa (Pascal) is applied to the adherend, and the cross-sectional shape of the applied photocurable sealant cured product (seal layer) corresponds to one width. A member having a seal layer, which is cured by light irradiation so as to have a height of 0.5 to 0.9.