JP2000178535A - Sealing agent composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide sealing agent compositions high in barrier curing to moisture which are quickly cured upon irradiation with rays and furthermore, can cure shadow portions without irradiation with rays with moisture in air. SOLUTION: In the photo-curable and moisture-curable sealing composition comprising (a) a polyisobutylene having a (meth)acrylic group and a hydrolyzable silicon group in the molecular chain, (b) a photoinitiator, and (c) a moisture curing catalyst, component (a) is obtained by the substitution reaction of a polyisobutylene having a silicon group bonded to two or more hydrolyzable groups in the molecular chain with a hydroxyl group-containing (meth)acrylate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photocurable and moisture-curable sealant composition. The present invention relates to a curable and moisture-curable sealant composition. In particular, the cured product of the composition of the present invention has low moisture permeability and is suitable for sealing electronic parts and the like that dislike moisture.

[0002]

2. Description of the Related Art Silicone resins which cure with moisture in the air have been well known as sealant compositions. Silicone resin is excellent in heat resistance and cold resistance and has sufficient performance as a general-purpose sealant, and is widely used for construction, automotive equipment and the like. However, as can be seen from the fact that a silicone resin cures a thick film by atmospheric moisture, the cured product has a relatively high moisture permeability. For this reason, silicone resin has been insufficient for sealing a case or the like of a component that stores therein an electronic component whose performance is deteriorated or damaged by moisture.

[0003] The above-mentioned silicone resin has a hydrolyzable group bonded to a silicon atom and has a silicon atom-containing group which can be crosslinked by forming a siloxane bond (hereinafter referred to as "hydrolyzable silicon group"). ), And those using an oxyalkylene-based polymer or an isobutylene-based polymer as the molecular main chain are already known. Since these are cured at normal temperature by moisture to obtain a rubber-like cured product, they have been conventionally used. However, in any case, there is a problem that curing by moisture has low reactivity and requires a long time for curing. Further, the isobutylene-based polymer having a hydrolyzable silicon group has a lower moisture permeability than the oxyalkylene-based polymer or dimethylsiloxane-based polymer having a hydrolyzable silicon group, so that the moisture curability is very poor, and the There is a problem that the curability is poor. Therefore, 2
It must be of a liquid mixing type, which is inconvenient.
As a rubber material having low moisture permeability, an isobutylene-based polymer is preferable. However, as described above, there are many problems such as a very low curing speed when curing is performed only with moisture.

[0004] In order to solve such a problem, some studies have been made on imparting photocuring performance to polyisobutylene. In the adhesive composition of JP-A-9-151366, a liquid resin having a functional group polymerizable by irradiation with high energy rays and a hydrolyzable silicon group at the end of a polyolefin polymer such as polyisobutylene is exemplified. However, there are problems that the synthesis process is very complicated and difficult and the reaction time is long. In addition, this moisture curability is intended to improve the adhesive strength after forming a film by photocuring.

Japanese Patent Application Laid-Open No. Hei 10-87726 proposes a method for producing an acrylic-functional polyisobutylene. However, since it has only an acrylic functional group and no moisture-curable functional group, it is not exposed to light. Shading does not cure. In addition, since a photoreactive group is added after synthesizing polyisobutylene having a terminal silanol, there is a problem that the production process is multi-step and the reaction time is long.

[0006]

Basically, polysiloxane and polyalkylene have photo-curing and moisture-curing properties because they have both reactive groups such as hydrolyzable silicon groups and photo-curing groups such as acrylic groups. It is already known that dual curing can be achieved. It is expected that a dual cured composition having polyisobutylene in the main chain can also be easily achieved by the above method, but the moisture-curable isobutylene to which the ultraviolet-curable group added by the above method is added has a high moisture permeability of the cured product, It is insufficient as a sealant for a member or the like for accommodating an electronic component whose performance is deteriorated or damaged by moisture. In particular, the moisture permeability of the portion cured by light irradiation was further increased, and a material cured by a rapid curing method using light curing was not suitable for sealing from moisture.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the conventional curable resin composition,
Photo-curing and moisture curing quickly by light irradiation at room temperature, and also cures light-irradiated parts such as shaded areas with moisture in the air, and further cures semi-cured parts with light irradiation. An object of the present invention is to provide a curable resin composition. That is, the present invention can be photo-cured and moisture-cured comprising (a) polyisobutylene having a (meth) acryl group and a hydrolyzable silicon group in a molecular chain, (b) a photoinitiator, and (c) a moisture curing catalyst. In the sealant composition, (a) is obtained by a substitution reaction between polyisobutylene having a silicon group bonded to two or more hydrolyzable groups in a molecular chain and a hydroxyl group-containing (meth) acrylate. A photocurable and moisture-curable sealant composition characterized by the following characteristics.

In the present invention, the (a) polyisobutylene having a (meth) acrylic group and a hydrolyzable silicon group at the molecular terminal has a silicon group bonded to two or more hydrolyzable groups in the molecular chain. It can be obtained by reacting polyisobutylene with a hydroxyl group-containing (meth) acrylate. In this reaction, a hydrolyzed silicon group and a hydroxyl group are bonded by a substitution reaction. The substitution reaction can be obtained by heating at room temperature to 150 ° C. using a non-catalyst or a transesterification catalyst or a moisture curing catalyst. It is preferable to react one hydrolyzable silicon group with one hydroxyl group-containing (meth) acrylate. Here, the (meth) acryl group in the present invention represents an acryloyloxy group or a methacryloyloxy group.

The liquid resin having hydrolyzable silicon groups at both ends used in the synthesis of (a) has a main chain of polyisobutylene. The main chain polyisobutylene in which at least 50 mol%, preferably 80 mol%, of the repeating units are isobutylene units of the formula To achieve low moisture permeability, the component (a) has a number average molecular weight of 1,000.
It is preferably from 20,000 to 20,000.

[0010]

## STR1 ##-(CH ₂ -C (CH ₃ ) ₂ )-

[0011] Any linear or branched polymer or copolymer thereof. One or several hydrocarbon monomers, such as isomers of styrene or butylene and derivatives of styrene, isoprene and butadiene, are copolymerized with isobutylene. Particularly preferred comonomers are selected from 1-butene, α-methylstyrene, or isoprene. Most preferably, the polymer is a homopolymer consisting essentially of isobutylene units.

The hydrolyzable silicon group is a silicon group bonded to the hydrolyzable group, and the hydrolyzable group is not particularly limited, and a conventionally known hydrolyzable group can be used. Specific examples include a hydrogen atom, a halogen atom, an alkoxy group, an acyloxy group, a ketoximate group, an amino group, an amide group, an aminooxy group, a mercapto group, and an alkenyloxy group. Among these, an alkoxy group is particularly preferred. The hydrolyzable group bonded to the silicon group can be a moisture-curable reactive group.

Two or more hydrolyzable groups can be bonded to one silicon atom, that is, two or three. If only one hydrolyzable group is bonded to the silicon group, the addition of the (meth) acryl group eliminates the presence of a moisture-curable reactive group. Preferably, there are three hydrolyzable groups bonded to the silicon group. That is, a compound having trialkoxysilane in the molecule of isobutylene is a preferable example.

It is sufficient that at least one hydrolyzable silicon group is present in the polyisobutylene molecule.
It is better to have two or more in the molecule. The hydrolyzable silicon group may be present at the end of the polyisobutylene molecular chain, in the middle, or both. In particular, when hydrolyzable silicon groups are present at both ends of the molecular chain, the amount of effective network chains of the polyisobutylene component contained in the finally formed cured product increases, so that a high-strength, high-extension rubber is used. It is preferable from the viewpoint that a cured state can be easily obtained.

The introduction of the hydrolyzable silicon group into the polyisobutylene may be carried out by a known method, for example, a saturated hydrocarbon polymer having a functional group such as a hydroxyl group or an acid anhydride group at the terminal or main chain. To react an organic compound having an active group and an unsaturated group that are reactive with the functional group,
Next, hydrosilylation may be carried out by reacting the obtained reaction product with hydrosilane having a hydrolyzable group. Also,
The polyisobutylene having a hydrolyzable silicon group can produce a terminal functional type, preferably an all-terminal functional type polyisobutylene obtained by a polymerization method called an inifer method. Such a production method is described, for example, in JP-A-63-663.
041, 63-6003, and JP-A-9-2
No. 86895.

The number average molecular weight of the saturated hydrocarbon polymer having a hydrolyzable silicon group is preferably about 500 to 50,000, particularly preferably about 1,000 to 20,000. In the present invention, such a saturated hydrocarbon polymer may be used alone or in combination of two or more. Such a liquid resin having a hydrolyzable silicon group is very easy to synthesize, but it is easy to obtain a finished product on the market such as "Epion" manufactured by Kanegafuchi Chemical Industry Co., Ltd.

The hydroxyl group-containing (meth) acrylate used in the synthesis of (a) has at least one (meth) acryl group and a hydroxyl group in the molecule. For example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, hydroxydiethylene glycol (meth) acrylate, butoxyhydroxypropyl acrylate, phenoxyhydroxypropyl acrylate, hydroxypropyl dimethacrylate , Diethylene glycol bis (hydroxypropyl acrylate),
Examples include trimethylolpropane di (meth) acrylate, pentaerythritol tri (meth) acrylate, butanediol monoacrylate, polyethylene glycol (meth) acrylate, and glycerol acrylate methacrylate.

Since the addition amount of the hydroxyl group-containing (meth) acrylate is only required to sensitize the system, it is sufficient that at least one hydroxyl group-containing (meth) acrylate is present in one molecule of the oligomer. The range may be 0.01 to 30% by weight based on the total weight of the oligomer,
Generally, it is preferable to be in the range of 5 to 20% by weight.

As the photocuring catalyst (B) used in the present invention, acetophenone, propiophenone, benzophenone, xanthol, fluorein, benzaldehyde, anthraquinone, camphorquinone, 2.4.6-
Trimethylbenzoyldiphenylphosphine oxide, triphenylamine, carbazole, 3-methylacetophenone, 4-methylacetophenone, 3-pentylacetophenone, 4-methoxyacetophenone, 3-
Bromoacetophenone, p-diacetylbenzene, 3-
Methoxybenzophenone, 4-allylacetophenone,
4-methylbenzophenone, 4-chloro-4 -.- benzylbenzophenone, 3-chloroxanthone, 3,9-
Examples include dichloroxantone, 3-chloro-8-nonylxantone, benzoyl, benzoin methyl ether, benzoin butyl ether, bis (4-dimethylaminophenyl) ketone, benzyl methoxy ketal, and 2-chlorothioxatone. The amount of the photopolymerization catalyst to be added is only 0.01% based on the total weight of the oligomers present in the composition since it is only necessary to slightly lighten the system.
The content may be in the range of 10 to 10% by weight, but is generally 0.1 to 10% by weight.
It is preferred to be in the range of 5% by weight.

As the moisture curing catalyst of the component (c) added to the sealant composition of the present invention, known ones can be used. Examples of the moisture curing catalyst include lead-2-ethyl octoate, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin bisacetylacetonate, dibutyltin dimethoxide, dibutyltin bis (trimethoxysilyl), and butyltin tri-2-ethyl. Hexoate,
Iron-2-ethylhexoate, cobalt-2-ethylhexoate, manganese-2-ethylhexoate, zinc-2-ethylhexoate, stannous caprylate, tin naphthenate, tin oleate, Metal lead of organic acid carboxylic acids such as tin butyrate, tin naphthenate, zinc naphthenate, cobalt naphthenate, zinc stearate, tetrabutyl titanate, tetra-2-ethylhexyl titanate, triethanolamine titanate, tetra (isopropenyloxy) ) Titanates, organic titanates such as diisopropoxybis (ethyl acetoacetate) titanium, diisopropoxybis (acetylacetone) titanium, organic titanium compounds such as organosiloxytitanium and β-carbonyltitanium, alkoxyaluminum compounds, benzyltriethyl Quaternary ammonium salts such as Nmo iodonium acetate, potassium acetate, sodium acetate, alkali metal lower fatty acids such as lithium oxalate, dimethyl hydroxylamine, such as dialkylhydroxylamine such as diethylhydroxylamine and the like.

The amount of the moisture curing catalyst used is 0.01 to 10 parts by weight, especially 0.1 to 5 parts by weight, based on the total weight of the oligomer.
Parts by weight are preferred. If the amount is too small, the curing of the present composition will be slow, and if it is too large, the curing will be too fast or the storage stability will be poor.

The sealant composition of the present invention basically comprises the above-mentioned components. Further, if necessary, the flow characteristics before curing are improved, and the mechanical properties required for the rubber-like elastic body after curing are improved. In order to provide, an inorganic filler in the form of fine powder can be added. As inorganic fillers, fumed silica, quartz fine powder, calcium carbonate, fumed titanium dioxide, diatomaceous earth, aluminum hydroxide, particulate alumina, magnesia, zinc oxide, zinc carbonate, and silanes, silazanes, Examples thereof include low-polymerization degree siloxanes, organic compounds, and the like, which are surface-treated.

Further, an organic solvent, a fungicide, a flame retardant, a plasticizer, a thixotropy-imparting agent, an adhesion-imparting agent, a curing accelerator, a pigment and the like can be added to the sealant composition of the present invention. Examples of the plasticizer include hydrocarbon compounds such as polybutene, hydrogenated polybutene, liquid polybutadiene, hydrogenated polybutadiene, paraffin oil and naphthenic oil, chlorinated paraffins, phthalic acid such as dibutyl phthalate and di (2-ethylhexyl) phthalate. Non-aromatic dibasic acid esters such as esters, dioctyl adipate, dioctyl sebacate, esters of polyalkylene glycol,
Phosphoric esters such as tricresyl phosphate and the like can be mentioned.

In addition to the photoinitiator as the radical polymerization initiator, a thermal polymerization, a rezox polymerization initiator or the like may be used in combination to impart thermal polymerization, rezox polymerization or the like. Then, for further adjusting the viscosity, a hydrolyzable diluent or the like may be added. Examples of the hydrolyzable diluent include a compound containing an unsaturated (vinyl double bond) group and a compound containing a hydrolyzable group. Specific examples include acrylic acid, methacrylic acid, and isobornyl acrylate. (Meth) acrylates such as isobornyl methacrylate, dicyclopentenyl acrylate, phenoxyethyl acrylate, 3- (meth) acryloylpropyltrimethoxysilane, 3- (meth) acryloylpropyldimethoxymethylsilane, vinyltrimethoxysilane Etc. may be added.

Since the composition of the present invention has extremely low moisture permeability, its performance is deteriorated by moisture or humidity in the air, and it is suitable for a sealant in a place where the moisture is not desirable, such as an electronic component, which is damaged. . Specifically, it is an in-vehicle outdoor electronic device, an electric device, a housing or a substrate of a control board, or the like.

The sealant composition of the present invention is used as a sealant for shutting off moisture, such as a sealant for a main body and a lid of a housing container and the like, a coating of an entire surface of an electronic substrate, and potting for embedding components in the container.

According to the present invention, it is possible to obtain a sealant having extremely low moisture permeability of a cured product by reacting (meth) acrylate having a hydroxyl group with polyisobutylene having a hydrolyzable silicon group in a molecular chain. . In particular, those cured by light irradiation, cured by moisture, and moisture-cured after light irradiation can all be low moisture-permeable sealants. On the other hand, by reacting methacryloxypropyltrimethoxysilane with polyisobutylene having an active hydrogen such as a hydroxyl group, polyisobutylene having a hydrolyzable silicon group and a (meth) acryl group can be obtained. The object has high moisture permeability, and cannot be used to seal a case of a component or the like that stores therein an electronic component whose performance is deteriorated or damaged by moisture. In particular, the portion cured by light irradiation had higher moisture permeability.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Example 1 400 g of Epion 303S (manufactured by Kanebuchi Chemical Industry Co., Ltd.), which is a polyisobutylene having a main chain having an average molecular weight of 10,000 and a methyldialkoxysilane added to a molecular weight terminal,
60 g of NK ester A-TMM-3 (manufactured by Shin-Nakamura Chemical Co., Ltd.), which is tetramethylol methane triacrylate,
200 g of an olefinic saturated hydrocarbon PS-32 (manufactured by Idemitsu Kosan Co., Ltd.) as a plasticizer, 4 g of 2,2-diethoxyacetophenone as a photoinitiator, and 4 g of dibutyltin dimethoxide as a moisture curing catalyst were mixed under reduced pressure. By stirring at 6 ° C. for 6 hours, a resin composition capable of photo-curing and moisture-curing was obtained.

Example 2 400 g of Epion 505S (manufactured by Kaneguchi Chemical Industry Co., Ltd.), which is a polyisobutylene having a main chain having an average molecular weight of 20,000 and a methyldialkoxysilane added to a molecular weight terminal,
NK ester A-TMM-3 (manufactured by Shin-Nakamura Chemical Co., Ltd.)
3 g, olefinic saturated hydrocarbon PS-3 as a plasticizer
2 (Idemitsu Kosan Co., Ltd.) 150 g, 2,2-
4 g of diethoxyacetophenone and 4 g of dibutyltin dimethoxide as a moisture curing catalyst were mixed under reduced pressure,
By stirring at 6 ° C. for 6 hours, a resin composition capable of photo-curing and moisture-curing was obtained.

Example 3 400 g of Epion 103S (manufactured by Kanebuchi Chemical Industry Co., Ltd.), which is a polyisobutylene having a main chain having an average molecular weight of 5,000 and methyl dialkoxysilane added to a molecular weight terminal,
40 g of NK ester 701A (manufactured by Shin-Nakamura Chemical Co., Ltd.)
100 g of an olefinic saturated hydrocarbon PS-32 (manufactured by Idemitsu Kosan Co., Ltd.) as a plasticizer, 4 g of 2,2-diethoxyacetophenone as a photoinitiator, and 4 g of dibutyltin dimethoxide as a moisture curing catalyst are mixed under reduced pressure, and then mixed at 80 ° C. At 6
After stirring for a time, a resin composition capable of being cured by light and moisture was obtained.

Comparative Example 1 2.6 g of methacryloxypropyltrimethoxysilane and 0.21 g of tetraisopropyl orthotitanate as a moisture curing catalyst were added to 50 g of polyisobutylene having a main chain having an average molecular weight of 10,000 and having hydroxyl groups at both ends. In a bottom flask, pressure was 10 mmHg and temperature was 80
C. and reacted for 6 hours using a rotary evaporator.
Further, 0.34 g of 2,2-diethoxyacetophenone as a photoinitiator and 0.1 g of dibutyltin dimethoxide were added thereto.
2 g was added and stirred to obtain a resin composition expected to be light-curable and moisture-curable.

Comparative Example 2 The procedure of Example 1 was repeated except that the hydroxyl group-containing acrylate was not used.

Curing Experiment The resin compositions obtained in Examples 1, 2 and 3 and Comparative Examples 1 and 2 were filled immediately after production with a capacity of 2 mm × 100 mm × 150 mm and 150 mW / cm ² with a 4 kW high-pressure mercury lamp.
Upon irradiation for 20 seconds, the liquid material became non-fluid. Furthermore, in order to cure the ultraviolet cured product with moisture, the temperature is 25 ° C.
It was left in an atmosphere of 50% humidity for 7 days.

The hardness of these cured products (Shore hardness A,
Asker hardness C), tensile strength and elongation were measured. The tensile strength and the elongation were measured by punching and cutting a cured product into a No. 3 rubber dumbbell mold in accordance with JIS-K-6301.

Further, Examples 1, 2, and 3 and Comparative Examples 1, 2
Was filled in the same container as described above, and was exposed to moisture without being irradiated with ultraviolet rays. Temperature 4 for moisture cured products
It was left for 7 days in an atmosphere of 0 ° C. and 95% humidity. Similarly, hardness (Shore hardness A, Asker hardness C), tensile strength,
The elongation was measured.

In addition, the cured thickness of the cured product after ultraviolet curing and moisture curing was measured. UV irradiation condition is 4
Irradiate 150mW / cm ² × 20 seconds with kW high pressure mercury lamp,
Moisture curing was measured after standing for 3 days in an atmosphere at a temperature of 25 ° C. and a humidity of 50%. Table 2 shows the results.

[0037]

[Table 1]

Comparative Example 3 Silyl SAT030, a polyether having a hydrolyzable silicon group at a terminal (manufactured by Kaneka Chemical Co., Ltd., viscosity 4500)
mPa · s) 800 g, tricresyl phosphate 800 g glycerol acrylate methacrylate 40 g 2,2-diethoxyacetophenone 8 as photoinitiator
g, 8 g of dibutyltin dimethoxide as a hydrolysis catalyst were mixed in a nitrogen atmosphere, and the mixture was stirred at 80 ° C. for 6 hours to obtain a resin composition capable of photo-curing and moisture-curing.

Comparative Example 4 400 g of polydimethylsiloxane (viscosity: 300 mPa · s) blocked with methyldimethoxysilyl groups at both ends, N
K ester A-TMM-3 (manufactured by Shin-Nakamura Chemical Co., Ltd.) 40
g, 2,2-diethoxyacetophenone 4 g, dibutyltin bisacetylacetonate 4 g, and the above were mixed in a nitrogen atmosphere, and stirred at 80 ° C. for 6 hours to obtain a resin composition capable of photo-curing and moisture-curing. Was.

Further, Examples 1, 2, and 3 and Comparative Examples 1, 2,
The moisture permeability test of a cured product obtained by curing the sealant composition adjusted in 3 and 4 with ultraviolet light and moisture was conducted according to JIS Z-0208 (19).
76). Using a cured product having a thickness of 1.6 mm, moisture permeability was tested at 60 ° C. × 95% RH for 24 hours, 48 hours, and 72 hours.

[0041]

[Table 2]

[0042]

The present invention relates to a resin composition which can be cured by light and moisture, and in particular, has excellent thick film curability by light curing, and is further cured by light irradiation, cured by moisture, and cured by light. All of the cured products that have been moisture-cured after irradiation can be low moisture-permeable sealants. Therefore, it is useful as a sealant in cases where electronic components or the like whose performance is deteriorated or damaged by moisture are housed inside.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4H017 AA03 AA31 AB01 AB07 AB15 AC05 AC08 AD05 AE04 4J011 QB01 SA01 SA21 SA51 SA64 WA06 4J027 AA00 AF05 CB10 CC00 CC04 CD06

Claims (3)

[Claims] 1. Photocurable and moisture curable compositions comprising (a) polyisobutylene having a (meth) acrylic group and a hydrolyzable silicon group in the molecular chain, (b) a photoinitiator and (c) a moisture curing catalyst. In the sealant composition, (a) is 2
Photocurable and moisture-curable seals obtained by a substitution reaction between polyisobutylene having a silicon group bonded to at least one hydrolyzable group in a molecular chain and a hydroxyl group-containing (meth) acrylate. Composition. 2. The amount of each component of the sealant composition is 100 parts by weight of polyisobutylene having a silicon group bonded to two or more hydrolyzable groups in a molecular chain, and a hydroxyl group-containing (meth) acrylate. 0.1 to 20 parts by weight, (b) photocuring catalyst 0.1 to 10 parts by weight, (c) moisture curing catalyst
The light-curable and moisture-curable sealant composition according to claim 1, wherein the amount is from 0.01 to 10 parts by weight. 3. The light-curable and moisture-curable sealant composition according to claim 1, wherein the sealant seals a part whose performance is deteriorated or damaged by moisture. .