JP2002302664A - Photocurable silicone composition for hardly adherable material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photocurable silicone composition excellent in adhesion to a hardly adherable material. SOLUTION: This photocurable silicone composition is characterized in that comprising (a) 100 pts.wt. curable organopolysiloxane represented by formula (1) and having (meth)acrylic groups at both the molecular ends, (b) 10-100 pts.wt. acrylic ester selected from among isobornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, and dicyclopentanyl (meth)acrylate, and (c) 0.01-10 pts.wt. photoinitiator selected from among benzophenone, benzophenone derivatives, benzyl formate, and methylbenzoyl formate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photocurable silicone composition, and more particularly to a photocurable silicone composition having excellent adhesion to hardly adherent materials. In particular, silicone rubber, EPDM rubber, soft PVC,
Polypropylene (PP), polyethylene (PE), polyacetal, polyethylene terephthalate (PET),
The present invention relates to a photocurable silicone composition having excellent adhesiveness to a poorly adhesive material such as polybutylene terephthalate (PBT) and polypropylene sulfite (PPS).

[0002]

2. Description of the Related Art Silicone is a substance having high industrial utility such as chemical resistance, impact resistance, vibration resistance, heat stress resistance and low-temperature properties, utilizing a flexible cured product and its elasticity. . However, conventional one-part RTV-silicone cures by condensation reaction due to moisture, and it takes a considerable time to completely cure. For this reason, silicones that cure by light irradiation have been developed. For example, there is one in which a silanol-organopolysiloxane at the terminal is reacted with aminoalkoxysilane, the terminal is changed to an amino group, and glycidyl (meth) acrylate is added to enable photocuring (Japanese Patent Application Laid-Open No. 55-112262). In addition, by reacting a terminal silanol organopolysiloxane with an acrylic-functional trialkoxy, a curable organopolysiloxane composition having both functions of moisture curing and light curing can be obtained (Japanese Patent Publication No. 6-51774). However, there is no mention of a composition having excellent adhesiveness to a poorly adhesive material.

On the other hand, a composition of a reactive organopolysiloxane in which an organopolysiloxane having a terminal amino group is blocked with a vinyl group-containing isocyanate, a (meth) acrylate and (meth) acrylic acid is excellent for a plastic substrate. (See Japanese Unexamined Patent Publication No.
184256). However, such a photocurable silicone composition generally has a low resin strength, a coating material,
Although it can be used for applications such as sealing materials, it is not suitable as an adhesive. Especially silicone rubber, EPDM rubber, P
P, PE, PET, PBT, PPS, polystyrene,
Poor adhesion and poor adhesion to poorly adherent materials such as soft PVC and polyacetal.

Various surface treatments have been applied to improve the adhesion and adhesion to such difficult-to-bond materials. For example,
Ozone treatment, ultraviolet irradiation, corona discharge and plasma treatment,
Ion beam processing, sputter etching processing, casi
Examples include ng treatment, steam treatment, surface grafting, solvent treatment, chemical treatment, primer treatment such as a coupling agent, and surface treatment such as monomer / polymer coating.
In addition, a method of forming a roughened surface by mechanical processing is actually used. Such a surface treatment process requires equipment and a process time, and in the case of a chemical treatment, there is a problem that the environment must be considered.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve the drawbacks of the prior art, and has particularly excellent photocurability, silicone rubber, EPDM rubber, soft PVC, PP, PE, polyacetal, and the like. An object of the present invention is to provide a silicone composition having a high adhesive strength even with difficult-to-bond materials such as PET and PBT and easy to manufacture.

[0006]

Means for Solving the Problems The present invention has been intensively studied in order to solve the above-mentioned problems, and (a) an acrylic or methacrylic group at both molecular terminals represented by the following general formula (1): Curable organopolysiloxane 10 having
0 parts by weight, (b) isobornyl (meth) acrylate,
10-100 parts by weight of an acrylate ester selected from dicyclopentenyl (meth) acrylate, dicyclopentanyl (meth) acrylate, and (c) a photoinitiator selected from benzophenone, a benzophenone derivative, benzyl or methylbenzoyl formate Agent 0.01 ~
An object of the present invention is to provide a photo-curable silicone composition for hard-to-adhesion materials, comprising 10 parts by weight.

[0007]

Embedded image

(Wherein R ¹ and R ⁵ are divalent hydrocarbon groups,
² represents a monovalent hydrocarbon group; R ³ and R ⁴ represent hydrogen or a monovalent hydrocarbon group; X represents a hydroxyl group or a hydrolyzable group; k is an integer of 0 or 1; Integer, m is 10
An integer of 10000, n is an integer of 0 or 1, and a is an integer of 0 to 2)

Next, the components constituting the silicone composition of the present invention will be described. The curable organopolysiloxane having an acrylic group or a methacrylic group at both molecular terminals, which is the component (a) of the present invention, is represented by the general formula (1). (Wherein R ¹ and R ⁵ are divalent hydrocarbon groups, R ² is a monovalent hydrocarbon group, R ³ and R ⁴ are hydrogen or a monovalent hydrocarbon group, X is a hydroxyl group or a hydrolyzable group. And k is 0
Or an integer of 1, j is an integer of 0 to 4, m is 10 to 10000
, N is an integer of 0 or 1, and a is an integer of 0 to 2.)

Examples of the divalent hydrocarbon group represented by R ¹ and R ⁵ in the formula (1) include an alkylene group such as a methylene group, an ethylene group and a propylene group, and an arylene group such as a phenylene group. It may be different at the ends.
Further, a monovalent hydrocarbon group represented by R ² and R ³ , R ⁴
Examples of the hydrogen or monovalent hydrocarbon group represented by are an alkyl group such as a methyl group, an ethyl group, a propyl group and a butyl group, an alkenyl group such as a vinyl group and an allyl group, a benzyl group, and a substituted alkyl group (isobornylalkyl). Or a dicyclopentenylalkyl group), or a group in which a hydrogen atom of these groups is partially substituted with a halogen atom or the like, and they need not all be the same. Also, X
Examples of the hydrolyzable group represented by are an alkoxy group such as a methoxy group, an ethoxy group, and a propoxy group, an oxime group, an aminooxy group, a propenoxy group, and an acetoxy group.

[0011] Such an organopolysiloxane can be synthesized by a conventionally known method. To illustrate, the following formula

Embedded image

(Wherein R has the same meaning as R ² described above, and n represents a positive integer) and a diorganopolysiloxane in which both terminals of the molecular chain are blocked by a hydroxyl group and one molecule of water. It can be synthesized by reacting a reactive silane compound having two or three decomposable groups and having a (meth) acryl group as another reactive group in the absence or presence of a catalyst. Alternatively, it can be synthesized by reacting a reactive silane compound having an amino group in the absence or presence of a catalyst, and further reacting a group having an amino group such as isocyanate and a compound having a (meth) acryl group.

The catalyst used includes amines, carboxylic acids and metal carboxylates such as zinc, tin and iron, titanates and organic titanates. The molar ratio of the alkoxysilane compound having a (meth) acrylic group or an amino group / SiOH in the condensation reaction is at least 1, preferably 1 to 10, and the reaction can be carried out at room temperature to 150 ° C. Although not essential, it is preferred that by-product alcohol be removed.

The reactive silane compound having a (meth) acrylic group used in the above reaction includes 3-acryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-acryloyloxypropylmethyldimethoxysilane, -Methacryloyloxypropylmethyldimethoxysilane and the like.

The reactive silane compound having an amino group used in the above reaction includes 3-aminopropyltrimethoxysilane, (β-aminoethyl) -γ-aminopropyltrialkoxysilane, (γ-aminopropyl) -Β-aminoethyl trialkoxysilane, (γ-
Silane compounds of primary amines such as aminopropyl) -γ-aminopropyltrialkoxysilane, aminopropyltrialkoxysilane, aminopropylmethyldialkoxysilane and N-methylaminotrimethoxysilane, N-benzylaminopropyltrimethoxysilane, etc. Secondary amine silane compound or primary amine silane compound [3-aminopropyltrimethoxysilane, (β-
(Aminoethyl) -γ-aminopropyl trialkoxysilane, (γ-aminopropyl) -β-aminoethyl trialkoxysilane, (γ-aminopropyl) -γ-aminopropyl trialkoxysilane, aminopropyl trialkoxysilane, aminopropyl Methyl dialkoxy silane] and various acrylate monomers, and a secondary amino silane compound obtained by a Michael addition reaction, or a compound of the following formula.

[0016]

Embedded image

In general, when a photocurable acrylic group is introduced into the above-mentioned amino group-containing organopolysiloxane,
For example, an addition reaction of an isocyanate containing a (meth) acrylic group-containing isocyanate or a carboxylic anhydride having an unsaturated double bond to an amino group, or (meth) acrylic acid, (meth) acrylic anhydride, (meth) acrylic chloride, or the like. , And N-alkoxycarbonyl (meth) acrylamide.

The (meth) acrylic group-containing isocyanate contains at least one vinyl group as a photocurable functional group in one molecule.
And a compound having an isocyanate group as a functional group for further reaction with an amino group. Specific examples include methacryloyl isocyanate, 2-isocyanatoethyl methacrylate, isopropenyl-2,2-dimethylbenzyl isocyanate, and , 4-tolylene diisocyanate, 2,6-tolylene diisocyanate,
Isocyanate group-containing (meth) acrylate obtained by the reaction of a compound having two or more isocyanate groups such as 1,5-naphthalenediisocyanate and a (meth) acrylate having a hydroxyl group such as 2-hydroxyethyl methacrylate and 2-hydroxypropyl methacrylate. Etc. are exemplified.

Examples of the carboxylic anhydride having an unsaturated double bond include maleic anhydride. Further, (meth) acrylic acid, (meth) acrylic anhydride, (meth) acrylic acid chloride, and N-alkoxycarbonyl (meth) acrylamide are also exemplified.

The addition reaction is usually carried out using an amino group-containing organopolysiloxane containing an amino group and a (meth) acrylic group-containing isocyanate or a carboxylic anhydride having an unsaturated double bond;
It is carried out by mixing (meth) acrylic acid, (meth) acrylic anhydride, (meth) acrylic acid chloride, N-alkoxycarbonyl (meth) acrylamide, and the like in a sufficient relationship to sufficiently react. Usually, the former is added in an amount of 2 mols or more per mol of the former, and is added at room temperature to 150
The reaction is carried out under heating at about ℃.

The viscosity of the curable organopolysiloxane at 25 ° C. is in the range of 10 mPa · s to 1000 Pa · s. If the viscosity is less than 10 mPa · s, the cured elastomer has excellent physical properties, particularly high flexibility and high flexibility. This is because elongation cannot be provided, and 1000 Pa. s
If it is larger than this, the viscosity of the composition becomes high, and the workability at the time of construction becomes extremely poor. Therefore, more preferably 100 mPa. s to 500 Pa. s.

Next, the component (b) used in the present invention is a component that acts as an adhesion-imparting agent for the present composition and improves the resin strength and adhesion of the cured product. It is selected from isobornyl (meth) acrylate, dicyclopentenyl (meth) acrylate, and dicyclopentanyl (meth) acrylate. Other (meth) acrylic acid esters do not show good adhesion to poorly adherent substances. Component (b) is added in an amount of 10 to 100 parts by weight per 100 parts by weight of component (a). In other ranges, no improvement in adhesion to poorly adherent substances is exhibited.

The component (c) of the present invention is a photocuring catalyst selected from benzophenone, a benzophenone derivative, benzyl or methylbenzoyl formate. Examples of the benzophenone derivative include 1,4-dibenzoylbenzene, 2-benzoylnaphthalene, 4-benzoylbiphenyl, 4-enzoyldiphenyl ether,
Acrylated benzophenone, 2,4,6-trimethylbenzophenone, 4-methylbenzophenone, 4,4'-
Bisdiethylaminobenzophenone and the like can be mentioned.
The amount of the component (c) added may be in the range of 0.01 to 10% by weight based on the total weight of the oligomers present in the composition, but is generally in the range of 0.1 to 5% by weight. Is preferred.

In order to improve the photocurability, a small amount of a photocuring catalyst or a photosensitizer other than the component (c) can be added.
When the composition of the present invention has a moisture reactive group, a moisture curing catalyst can be added to impart moisture curability.
Known moisture curing catalysts can be used.

Examples of the moisture curing catalyst include lead-2-ethyl octoate, dibutyltin diacetate, dibutyltin dilaurate, butyltin tri-2-ethylhexoate, iron-2-ethylhexoate, and cobalt-2- Ethylhexoate, manganese-2-ethylhexoate,
Zinc-2-ethylhexoate, stannous caprylate,
Metal lead of organic acid carboxylic acid such as tin naphthenate, tin oleate, tin butylate, tin naphthenate, zinc naphthenate, cobalt naphthenate, zinc stearate; tetrabutyl titanate, tetra-2-ethylhexyl titanate, triethanol Organic titanates such as amine titanate, tetra (isopropenyloxy) titanate, diisopropoxybis (ethyl acetoacetate) titanium, diisopropoxybis (acetylacetone) titanium; organic titanium compounds such as organosiloxytitanium and β-carbonyltitanium An alkoxyaluminum compound; a quaternary ammonium salt such as benzyltriethylammonium acetate; a lower fatty acid of an alkali metal such as potassium acetate, sodium acetate and lithium oxalate; Min, dialkylhydroxylamine such as diethylhydroxylamine; and the like. The amount of the moisture curing catalyst used is preferably 0.01 to 10 parts by weight, particularly preferably 0.1 to 5 parts by weight, based on the total weight of the oligomer. 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 composition of the present invention basically comprises the above-mentioned components. If necessary, the composition further improves the flow characteristics before curing and imparts necessary mechanical properties to the rubber-like elastic body after curing. For this purpose, a finely powdered inorganic filler 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 composition of the present invention.

In addition to a photoinitiator as a radical polymerization initiator, a thermal polymerization initiator, 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, dimethyl silicone oil or a reactive diluent may be added. Unsaturated (vinyl double bond) as reactive diluent
There are a compound containing a group and a compound containing a hydrolyzable group, and specifically, acrylic acid, methacrylic acid,
(Meth) acrylic acid esters such as phenoxyethyl acrylate; unsaturated groups such as 3- (meth) acryloylpropyltrimethoxysilane, 3- (meth) acryloylpropyldimethoxymethylsilane, vinyltrimethoxysilane and tetraethoxysilane; A compound containing a decomposable group,

[0028]

Embedded image

Examples of the silane coupling agent include:

[0030]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Production Example 1 Silanol-terminated polydimethylsiloxane (viscosity 5 Pa.
s) To 1800 g, 36.0 g of 3-aminopropylmethyldimethoxysilane was added, and 100 ° C.
Stir for hours. Thereafter, vacuum is applied to remove excess by-product methanol. To this, 34.2 g of methacryloyloxyethyl isocyanate was added, and the mixture was stirred and reacted at room temperature for 1 hour while replacing with nitrogen to obtain a terminal methacrylate polydimethylsiloxane having a viscosity of 26 Pas.

Production Example 2 Silanol-terminated polydimethylsiloxane (viscosity 1 Pa.
s) 43.2 g of 3-aminopropyltrimethoxysilane was added to 1800 g, and the mixture was stirred and reacted at 100 ° C. for 2 hours while replacing with nitrogen. Thereafter, vacuum is applied to remove excess by-product methanol. To this, 41 g of 2-isocyanateethyl methacrylate was added, and the mixture was stirred and reacted at room temperature for 1 hour under nitrogen replacement to obtain a terminal methacrylate polydimethylsiloxane having a viscosity of 5 Pa · s.

Examples 1 to 6 and Comparative Examples 1 to 2 The resins obtained in Production Examples 1 and 2 were mixed with the compounds described in the table, such as isobornyl acrylate and methylbenzoyl formate, in parts by weight described in the table. In addition, the mixture was defoamed and stirred under reduced pressure until the mixture became uniform to obtain a photocurable silicone composition.
However, the fumed silica powder used had been surface-treated with dimethyldichlorosilane, and the benzophenone derivative was 2,2.
A mixture of 4,6-trimethylbenzophenone and 4-methylbenzophenone was used. In Comparative Examples 2 and 3, the respective components were not uniformly mixed and caused phase separation to be clouded.

The resin compositions obtained in these Examples and Comparative Examples were filled to a capacity of 2 mm × 150 mm × 150 mm in depth and irradiated with a 4 kW high-pressure mercury lamp at 150 mW / cm × 20 seconds to cure. In addition, JIS-K-624
According to No. 9, the hardness (Shore A), tensile strength, elongation and tensile shear adhesive strength of the ultraviolet cured product were measured. Table 1 shows the results.

[0034]

[Table 1]

[0035]

The present invention relates to a photocurable silicone composition, and more particularly to a photocurable silicone composition having excellent adhesion to hard-to-bond materials, particularly silicone rubber, EPDM rubber, Excellent adhesion to poorly adherent materials such as soft PVC, polypropylene (PP), polyethylene (PE), polyacetal, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polypropylene sulfite (PPS) A photocurable silicone composition could be achieved.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J011 AC04 QA03 QB25 SA21 SA22 SA23 SA24 SA25 SA26 SA28 SA29 SA42 SA61 UA01 VA01 WA06 4J027 AF06 AJ02 BA07 CB10 CC05 CD09 4J040 EK101 FA151 FA152 GA01 GA05 GA07 GA08 GA14 GA19 GA22 HB19 KA13 MA10 MA12 PA32

Claims (1)

[Claims] 1. (a) 100 parts by weight of a curable organopolysiloxane having an acrylic group or a methacrylic group at both molecular terminals represented by the following structural formula (1), (b) isobornyl (meth) acrylate, dicyclo Acrylate 10-10 selected from pentenyl (meth) acrylate and dicyclopentanyl (meth) acrylate
A photocurable silicone composition for a poorly adherent material, comprising: parts by weight; and (c) 0.01 to 10 parts by weight of a photoinitiator selected from benzophenone, a benzophenone derivative, benzyl or methylbenzoyl formate. (Wherein R ¹ and R ⁵ are divalent hydrocarbon groups, R ² is a monovalent hydrocarbon group, R ³ and R ⁴ are hydrogen or a monovalent hydrocarbon group,
X represents a hydroxyl group or a hydrolyzable group, and k represents 0 or 1.
J is an integer of 0 to 4, m is an integer of 10 to 10000, n is an integer of 0 or 1, and a is an integer of 0 to 2)