JP2005187615A - Ultraviolet-curing acrylic composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultraviolet-curing acrylic composition which has a rubber elasticity suitable for sealing use, to which ultraviolet-curing and moisture-curing properties can be imparted through an easy operation. <P>SOLUTION: The ultraviolet-curing acrylic composition comprises a (meth)acryloyl group-containing acrylic polymer, a hydrolyzable isocyanate group-containing silane compound of the formula: R<SP>1</SP><SB>n</SB>R<SP>2</SP><SB>m</SB>Si(OR)<SB>4-n-m</SB>(wherein R is a 1-3C linear or branched alkyl group; R<SP>1</SP>is an isocyanate alkyl group containing ≥3 carbons; R<SP>2</SP>is an alkyl group or an aralkyl group; n is 1 or 2; and m is 0 or 1), an ultraviolet-curing catalyst and a moisture-curing catalyst. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an ultraviolet curable acrylic composition. More specifically, the present invention relates to an acrylic composition that cures by moisture with respect to a portion that is cured by ultraviolet irradiation and is not cured by ultraviolet irradiation.

  Ultraviolet curing is performed in combination with anaerobic curing or moisture curing because curing does not occur in shaded areas where ultraviolet rays do not hit or deep areas where light is difficult to reach. However, a composition that combines anaerobic curability has the property that it is cured only at locations where air is blocked and metal ions are supplied.

  On the other hand, since there are no restrictions such as anaerobic curing, a number of compositions having a combination of moisture curing properties are conventionally known as follows.

A compound having a functional group that reacts with at least two isocyanates in one molecule is reacted with a diisocyanate, and further a compound having a hydroxyl group or the like and a (meth) acryloyl group in one molecule and a hydroxyl group in one molecule. An ultraviolet curable resin obtained by reacting a compound having an alkoxysilyl group has been proposed, but only a hard product is disclosed which is complicated and expensive in reaction.
JP 62-172010 JP

An adhesive composition containing a photopolymerization initiator in a reaction product of 1 molar equivalent of diisocyanate and 0.5 to 1.5 molar equivalent of a (meth) acrylic monomer containing one hydroxyl group at the end has been proposed. It has the property that the cured product is hard.
JP-A 64-85268

A cured resin composition comprising an isocyanate group-containing (meth) acrylate, a photopolymerization initiator, and an elastomer has been proposed, but only a hard cured product is disclosed.
JP-A-5-97963

A reactive adhesive composition comprising a compound having an isocyanate group and two or more terminal vinyl groups in one molecule and a photopolymerization initiator has been proposed, but has a property that the cured product is hard.
JP 2001-240811 A

A rubber elastic composition comprising a polymer having an alkoxysilyl group and a (meth) acryloxy group at both ends of a linear rubber elastic polymer chain, a photopolymerization initiator, and a moisture curing catalyst has been proposed, but the reaction is complicated. Expensive.
Japanese Patent No. 2,660,549

A resin polymer having a hydrolyzable silyl group and a radically polymerizable (meth) acrylic group at the end is prepared by an addition reaction using the difference in reactivity between primary amine and secondary amine, and this is combined with radical polymerization initiator and moisture curing. A resin composition comprising a catalyst has been proposed, but the reaction is complicated and expensive.
Japanese Patent Laid-Open No. 5-311082

There has been proposed a resin composition comprising a reaction product of a polybutadienediol compound esterified with maleic anhydride at both ends and an epoxysilane coupling agent, a vinyl group-containing alkoxysilyl compound, a photopolymerization initiator, and a moisture curing catalyst. However, the oil resistance and heat resistance of the cured product are low.
JP-A-6-80825

A composition comprising a polymer having a (meth) acrylic group and a hydrolyzable silicon group in one molecule and a tackifier resin has been proposed, but a raw material having hydrolyzable groups introduced at both ends of the molecular chain The reaction process to obtain is complicated and expensive.
Japanese Unexamined Patent Publication No. 9-151366

A sealant composition comprising polyisobutylene having a (meth) acrylic group and a hydrolyzable silicon group in the molecular chain, a photopolymerization initiator, and a moisture curing catalyst has been proposed, but the oil resistance and heat resistance of the cured product have been proposed. Low.
JP 2000-178535 A

  These compositions are not suitable for sealing because the cured product is hard as described above, or the polymer is polysiloxane, polyisobutylene, polyether, polyester even if it is suitable for sealing. , Polybutadiene, acrylonitrile butadiene copolymer, etc., which have a relatively low level of oil resistance and heat resistance, and have a long process of imparting UV curability and moisture curability. In short, it was expensive.

  In general, acrylic rubber is known as a millable rubber with excellent heat resistance and oil resistance. However, almost all compositions that can be prepared by a simple operation are moisture-curing compositions that are UV-cured with an acrylic polymer. The current situation is not.

  An object of the present invention is to provide an ultraviolet curable acrylic composition having rubber elasticity suitable for sealing use, which can impart ultraviolet curable properties and moisture curable properties by a simple operation.

The object of the present invention is to provide a (meth) acryloyl group-containing acrylic polymer, a general formula
R ¹ _n R ² _m Si (OR) _4-nm
(Where R is a linear or branched alkyl group having ¹ to 3 carbon atoms, R ¹ is an isocyanate alkyl group having 3 or more carbon atoms, R ² is an alkyl group or an aralkyl group, n is 1 or 2, and m is 0 or 1) .This is achieved by an ultraviolet curable acrylic composition comprising a hydrolyzable isocyanate group-containing silane compound represented by: an ultraviolet curing catalyst and a moisture curing catalyst. The

  The ultraviolet curable acrylic composition according to the present invention is easy to prepare, and since it is one-component, it does not require the trouble of adding a catalyst and mixing two components, and there are problems such as air entrainment due to mixing. Not only is it possible to cure the seals by UV irradiation online, but then it can be further moisture cured offline, thus covering insufficient curing due to changes in the UV amount, such as changes in product shape and line speed. The reliability of the product can be improved.

  As the (meth) acryloyl group-containing acrylic polymer, an acrylic polymer having a functional group such as a carboxyl group, a hydroxyl group, an amino group, or a lower alkylamino group having 1 to 5 carbon atoms is preferably used. Such a functional group-containing acrylic polymer (prepolymer) is a vinyl monomer having these functional groups in an alkyl acrylate such as methyl acrylate, ethyl acrylate, butyl acrylate, etc., preferably unsaturated having these functional groups. About 5 to 20% by weight of a carboxylic acid monomer such as acrylic acid, methacrylic acid, maleic acid monoalkyl ester, 2-hydroxy (meth) acrylate, p-vinylaniline, 2- (tert-butylamino) ethyl methacrylate A product obtained by copolymerization to a certain extent can be used, and a commercially available product can also be used.

  As a method for introducing a (meth) acryloyl group into the acrylic prepolymer having a functional group thus obtained, a compound containing a group that reacts with these functional groups and a (meth) acryloyl group, preferably Includes a method of reacting an isocyanate compound or glycidyl compound containing a (meth) acryloyl group that can be reacted under relatively mild conditions near room temperature. The amount of the reaction may be 1 equivalent of the functional group of the prepolymer, and all functional groups may be reacted using 1 equivalent of the reaction compound, or the functional group may be left using 1 equivalent or less of the reaction compound. good.

For example, a carboxyl group-containing acrylic prepolymer and a (meth) acryloyl group-containing isocyanate compound CH ₂ = CR ₁ COOR ₂ NCO (R ₁ : hydrogen atom or methyl group, R ₂ : linear or branched having 0 to 4 carbon atoms) The product of the reaction with (like alkylene group) is preferably used as a (meth) acryloyl group-containing acrylic polymer. Such (meth) acryloyl group-containing isocyanate compounds include methacryloyloxyethyl isocyanate CH ₂ = C (CH ₃ ) COOCH ₂ CH ₂ NCO, acryloyl isocyanate CH ₂ = CHCOONCO, methacryloyloxyisobutyl isocyanate CH ₂ = C (CH ₃ ) COOCH ₂ C (CH ₃ ) ₂ NCO or the like is used, and methacryloyloxyethyl isocyanate is preferably used because it is easily available. As the (meth) acryloyl group-containing glycidyl compound, glycidyl (meth) acrylate is generally used.

カルボキシル基の活性水素1モルに対してイソシアネート基1モルが反応すると考えて、カルボキシル基1当量に対して同当量以下のイソシアネート化合物、好ましくはカルボキシル基を残すためにカルボキシル基1当量に対して約0.1〜0.8当量のイソシアネート化合物を、室温乃至約50℃で約1〜10日間程度反応させることにより行われる。 The reaction between the carboxyl group in the carboxyl group-containing acrylic prepolymer and the methacryloxy group-containing isocyanate compound is

Assuming that 1 mole of isocyanate group reacts with respect to 1 mole of active hydrogen of the carboxyl group, the isocyanate compound is less than or equal to 1 equivalent of carboxyl group, preferably about 1 equivalent of 1 equivalent of carboxyl group to leave the carboxyl group. The reaction is carried out by reacting 0.1 to 0.8 equivalents of an isocyanate compound at room temperature to about 50 ° C. for about 1 to 10 days.

  Also, a (meth) acryloyl group-containing isocyanate compound or a (meth) acryloyl group-containing glycidyl compound is reacted with an acrylic prepolymer having a functional group such as a hydroxyl group, an amino group, or a lower alkylamino group having 1 to 5 carbon atoms. In this way, a (meth) acryloyl group-containing acrylic polymer can be obtained. Also in this case, the reaction amount of the isocyanate group may be less than the equivalent of the functional group, and the reaction is carried out at a temperature of room temperature to about 50 ° C. for about 1 to 10 days.

General formula R ¹ _n R ² _m Si (OR) _4-nm
R: a linear or branched alkyl group having 1 to 3 carbon atoms
R ¹ : isocyanate alkyl group having 3 or more carbon atoms
R ² : alkyl group or aralkyl group having any carbon number
n: 1 or 2
m: 0 or 1
As the hydrolyzable isocyanate group-containing silane compound represented by γ-isocyanatopropyltrimethoxysilane (CH ₃ O) ₃ SiCH ₂ CH ₂ CH ₂ NCO or γ-isocyanatopropyltriethoxysilane ( CH ₃ CH ₂ O) ₃ SiCH ₂ CH ₂ CH ₂ NCO is used. The hydrolyzable isocyanate group-containing silane compound is used in an amount of 1 to 30 parts by weight, preferably 5 to 20 parts by weight, per 100 parts by weight of the acrylic polymer. If it is used in a proportion below this, the moisture curability will be insufficient, while if it is used in a proportion above this, the rubber will become too hard. Those having an R group having 4 or more carbon atoms have a slow hydrolysis rate, and those having an R ¹ group having less than 3 carbon atoms are not suitable for use because the compound is unstable.

  UV curing catalysts include intramolecular cleavage types such as bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, 1-hydroxycyclohexyl phenyl ketone, and 2,2-dimethoxy-1,2-diphenylethane-1-one. Any of these initiators can be used, and one or a combination of two or more of these can be used. The ultraviolet curing catalyst is used in a proportion of 0.1 to 5 parts by weight, preferably 0.5 to 3 parts by weight, per 100 parts by weight of the acrylic polymer. If it is used at a ratio below this, the curing rate will be slow, whereas if it is used at a ratio above this, the physical properties such as oil resistance will be reduced.

  Examples of moisture curing catalysts include dibutyltin dilaurate, tin soaps such as dibutyltin acetate, titanium chelates such as bisacetylacetonate diisopropoxytitanium, alkoxytitanium such as tetrabutyltitanate and tetraisopropyltitanate, acidic phosphoric acid monobutyl ester, Acid phosphates such as acid dibutyl ester are used alone or in combination of two or more. The moisture curing catalyst is used in a ratio of 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, per 100 parts by weight of the acrylic polymer. If it is used at a ratio below this, the moisture curing rate will be slow, and if it is used at a ratio above this, the rubber will become too hard.

  A reactive diluent, an organic solvent, a polyfunctional (meth) acrylate compound, and the like can be added to each of the above essential components as long as the objects of the present invention such as storage stability and rubber elasticity are not deviated.

  Examples of the reactive diluent include monoacrylates such as lauryl acrylate, 2-hydroxybutyl acrylate, 3-methoxybutyl acrylate, and methoxydipropylene glycol acrylate, and these are used for viscosity adjustment purposes.

  As the organic solvent, for example, an aprotic solvent such as ethyl acetate, butyl acetate, acetone, methyl ethyl ketone, dimethyl ether, and diethyl ether is used, and these are used for viscosity adjustment.

  As the polyfunctional (meth) acrylate compound, for example, 1,6-hexanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate and the like are used, and these are used for adjusting the crosslinking density.

  Further, fumed silica, quartz fine powder, plasticizer, carbon black, metal powder, foaming agent, flame retardant, gelling agent, pigment and the like can be added as necessary.

Each of the above components is prepared as an ultraviolet curable acrylic composition simply by mixing and leaving for about 1 to 5 days. This composition is UV-cured by irradiating with UV light at a light intensity of 100 to 1000 mW / cm ² (wavelength 300 to 460 nm) for about 10 seconds to about 5 minutes, and further has a temperature of 25 to 30 ° C. and a humidity of 30 to 80 Moisture curing is performed by being left in the state of% for about 1 to 2 weeks.

  Next, the present invention will be described with reference to examples.

Example 1
[Prepolymer production]
Ethyl acrylate 16 g, butyl acrylate 15 g, acrylic acid 1.7 g and lauryl mercaptan 0.67 g were charged into a 3 L four-necked flask equipped with a condenser, a dropping funnel and a thermometer, and using the dropping funnel, ethyl acrylate 34 g, A mixture of 28 g of butyl acrylate, 3.3 g of acrylic acid, 1.33 g of lauryl mercaptan and 0.1 g of azobisisobutyronitrile was added dropwise over 10 hours at a liquid temperature of 60 to 70 ° C. A containing prepolymer was prepared. The weight average molecular weight Mw measured using GPC was 25,000.

[Preparation of acrylic polymer]
Add methacryloyloxyethyl isocyanate CH ₂ = C (CH ₃ ) COOC ₂ H ₄ NCO (Showa Denko product Karenz MOI) 1.8 parts by weight to 100 parts by weight of this prepolymer, and let stand at room temperature for 3 days, containing methacryloyl group An isocyanate compound-modified acrylic polymer A was obtained.

[Production of test pieces]
Methacryloyl group-containing isocyanate compound-modified acrylic polymer A 100 parts by weight γ-isocyanatopropyltriethoxysilane 20 部
(Nihon Unicar product A-1310)
Lauryl acrylate 30 〃
Bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide 1
(Irgacure 819, product of Ciba Specialty Chemicals)
Dibutyltin dilaurate 2 〃
After mixing the above components and allowing them to stand for 1 day, they were poured into a 7mm thick tetrafluoroethylene plate with a 2mm deep groove at room temperature and irradiated with 200mW / cm ² (wavelength 365nm). After irradiating with UV light for 1 minute, it was left in a room at 25 ° C and 60% for 1 week to obtain a test piece.

The obtained test pieces were measured and evaluated for storage elastic modulus, adhesiveness and bending resistance.
Storage elastic modulus (dynamic elastic modulus): Measured using viscoelastic spectrometer SDM5600 (Seiko Denshi Kogyo Co., Ltd.) Adhesion: Evaluate dry with finger touch ○, non-dry with x Curvature: evaluated at 25 ° C as ◯ for those with no cracks when bent by hand, and x for those with cracks.

Example 2
In Example 1, the amount of γ-isocyanatopropyltriethoxysilane was changed to 5 parts by weight.

Example 3
In Example 1, instead of the methacryloyl group-containing isocyanate compound-modified acrylic polymer A, about 1/2 equivalent of glycidyl methacrylate was reacted with an acrylic polymer having a carboxyl group as a functional group, and a methacryloyl group, a hydroxyl group and a carboxyl group were reacted. The same amount of acrylic polymer with a group (Gakken Chemicals BGV-11) was used.

Example 4
In Example 1, instead of the methacryloyl group-containing isocyanate compound-modified acrylic polymer A, an acrylic polymer having a carboxyl group as a functional group was allowed to react with about 1 equivalent of glycidyl methacrylate, and an acrylic polymer having a methacryloyl group and a hydroxyl group was reacted. The same amount was used (Soken Chemicals BGV-12).

Example 5
In Example 1, instead of dibutyltin dilaurate, an equal amount of a mixture of acidic phosphoric acid monobutyl ester and acidic phosphoric acid dibutyl ester having a molar ratio of 1: 1 (Daihachi Chemical Industry AP-4) was used.

Example 6
In the preparation of the methacryloyl group-containing isocyanate compound-modified acrylic polymer A of Example 1, the same amount of methacryloyl isocyanate CH ₂ = C (CH ₃ ) COONCO (reagent) was used instead of methacryloyloxyethyl isocyanate, and the acryloyl group-containing Isocyanate-modified acrylic polymer B was obtained. This acrylic polymer B was used in the same amount in place of the acrylic polymer A in the production of the test piece.

Comparative Example 1
In Example 1, 5 parts by weight of vinyltrimethoxysilane (Nihon Unicar product A-171) was used in place of γ-isocyanatopropyltriethoxysilane.

Comparative Example 2
In Example 1, vinyltrimethoxysilane (A-171) was used in the same amount instead of γ-isocyanatopropyltriethoxysilane.

Comparative Example 3
In Example 1, 5 parts by weight of γ-methacryloxypropyltrimethoxysilane (Nihon Unicar product A-174) was used in place of γ-isocyanatopropyltriethoxysilane.

Comparative Example 4
In Example 1, in place of γ-isocyanatopropyltriethoxysilane, the same amount of γ-methacryloxypropyltrimethoxysilane (A-174) was used.

Comparative Example 5
A 3L 4-neck flask equipped with a condenser, dropping funnel and thermometer was charged with 16 g of ethyl acrylate, 10 g of butyl acrylate, 10 g of methoxyethyl acrylate, and 0.67 g of lauryl mercaptan. A mixture of 15 g of butyl acrylate, 15 g of methoxyethyl acrylate, 1.33 g of lauryl mercaptan and 0.1 g of azobisisobutyronitrile was added dropwise over a period of 10 hours at a liquid temperature of 60 to 70 ° C. and then reacted for another 16 hours. A system polymer C (weight average molecular weight Mw 26,000) was obtained. A test piece was prepared using this acrylic polymer C in the same manner as in Example 1.

The results obtained in the above examples and comparative examples are shown in the following table.
table
Measurement / Evaluation Items Real 1 Real 2 Real 3 Real 4 Real 5 Real 6 Ratio 1 Ratio 2 Ratio 3 Ratio 4 Ratio 5
Storage modulus (MPa) 0.61 0.20 0.65 0.72 0.58 0.59 0.12 0.12 0.50 3.60 0.10
Adhesiveness ○ ○ ○ ○ ○ ○ × × ○ ○ ×
Bending resistance ○ ○ ○ ○ ○ ○ ○ ○ × × ○

Since the ultraviolet curable resin composition according to the present invention can be easily prepared without going through complicated steps, it not only has extremely high industrial value, but also the cured product exhibits rubbery elasticity. It is preferably used as a sealing material.

Claims (5)

(Meth) acryloyl group-containing acrylic polymer, general formula
R ¹ _n R ² _m Si (OR) _4-nm
(Where R is a linear or branched alkyl group having ¹ to 3 carbon atoms, R ¹ is an isocyanate alkyl group having 3 or more carbon atoms, R ² is an alkyl group or an aralkyl group, An ultraviolet curable acrylic composition comprising a hydrolyzable isocyanate group-containing silane compound represented by the following formula: n is 1 or 2, and m is 0 or 1; an ultraviolet curing catalyst and a moisture curing catalyst.   The ultraviolet curable acrylic composition according to claim 1, wherein the (meth) acryloyl group-containing acrylic polymer is a (meth) acryloyl group and functional group-containing acrylic polymer.   The ultraviolet curable acrylic composition according to claim 2, wherein the functional group is a carboxyl group, a hydroxyl group, an amino group, or a lower alkylamino group having 1 to 5 carbon atoms.   (Meth) acryloyl group-containing acrylic polymer is carboxyl group, hydroxyl group, amino group or C1-C5 lower alkylamino group-containing acrylic polymer and (meth) acryloyl group-containing isocyanate compound or (meth) acryloyl group-containing 2. The ultraviolet curable acrylic composition according to claim 1, which is a reaction product with a glycidyl compound. A sealing material obtained by subjecting the acrylic composition according to claim 1 to moisture curing after ultraviolet curing.