JP2001303013A - Ultraviolet curable adhesive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultraviolet curable adhesive composition excellent in adhesive strength (shear strength) and in curing rate, in particular when an inorganic material such as glass is used as an adherend and capable of providing a cured product having a high hardness. SOLUTION: This ultraviolet curing type adhesive composition comprises an oxetane compound (a compound having an oxetane ring), a coupling agent and photopolymerization initiator and further preferably an alicyclic epoxy compound and a modified silicone oil.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an ultraviolet-curable adhesive composition. More specifically, the present invention relates to an ultraviolet-curable adhesive composition comprising an oxetane compound (a compound containing an oxetane ring).

[0002]

2. Description of the Related Art As an ultraviolet-curable adhesive composition, particularly an ultraviolet-curable adhesive composition containing an oxetane compound (compound containing an oxetane ring), for example,
An active energy ray-curable adhesive composition for lamination comprising a compound having four oxetane rings and a cationic photopolymerization initiator (JP-A-8-231938) is known. However, this composition is not satisfactory in terms of adhesive strength (shear strength) and curing speed, particularly when an inorganic material such as glass is used as the adherend.

[0003]

The object of the present invention is to provide a cured product having excellent adhesive strength (shear strength) and curing speed and high hardness, particularly when an inorganic material such as glass is used as an adherend. An object of the present invention is to provide a UV-curable adhesive composition that can be used.

[0004]

The object of the present invention is achieved by an ultraviolet-curable adhesive composition comprising an oxetane compound, a coupling agent, and a photopolymerization initiator.

[Oxetane compound] As the oxetane compound (compound containing an oxetane ring) used in the present invention, an ether-type bisoxetane compound represented by the formula (1) and having two oxetane rings in the molecule is used. Preferred examples are given.

[0006]

Embedded image (Wherein, R ¹ and R ² represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, n represents an integer of 0 to 30. Z represents n = 1
Represents an alkylene group (which may form an unsaturated bond, an aliphatic hydrocarbon ring, or an aromatic ring inside the carbon chain), and an integer of n = 2 to 30 represents an ethylene group. )

In the compound represented by the formula (1),
R ¹ and R ² represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and may be the same or different. Among the compounds, those in which R ¹ and R ² are the same as each other are preferable. Among them, those in which R ¹ and R ² are the same as each other and are any of a hydrogen atom, a methyl group, and an ethyl group are preferable. Among them, those in which R ¹ and R ² are the same as each other and are either a methyl group or an ethyl group are more preferable.

The following are specific examples of the compound represented by the formula (1). monoether bisoxetanes wherein n = 0, z = 1, wherein Z is an alkylene group (which may contain an unsaturated bond, an aliphatic hydrocarbon ring, or an aromatic ring in the carbon chain); Ether bis oxetanes n = an integer of 2 to 30, and Z is an ethylene group, polyether bis oxetanes

The monoether bisoxetanes include, for example, bis (3-ethyl-3-oxetanyl) methyl ether and bis (3-methyl-3-oxetanyl) methyl ether. The monoether bisoxetanes are, for example, 3-alkyl-3
It is synthesized by reacting -hydroxymethyloxetane with p-toluenesulfonyl chloride of 3-alkyl-3-hydroxymethyloxetane.

In the above diether bisoxetanes, the alkylene group (Z) may form an unsaturated bond, an aliphatic hydrocarbon ring or an aromatic ring inside the carbon chain. That is, examples of the alkylene group include an alkylene group having 2 to 12 carbon atoms such as an ethylene group, a tetramethylene group, and a hexamethylene group. An aliphatic hydrocarbon ring (cyclohexane ring) such as an alkylene group having 4 to 6 carbon atoms forming an unsaturated bond (such as a carbon-carbon double bond) or a group represented by the formula (3). And the like, an alkylene group having 2 to 6 carbon atoms (excluding ring carbon atoms), an xylylene group, and an aromatic ring (such as a benzene ring) in a carbon chain such as a group represented by the formula (4). An alkylene group having 2 to 6 carbon atoms (excluding ring carbon atoms) (o
-, M- and p- isomers).

[0011]

Embedded image

Examples of the diether bisoxetanes include 1,2-bis (3-ethyl-3-oxetanylmethoxy) ethane, 1,4-bis (3-ethyl-3-oxetanylmethoxy) butane, 1,6 -Bis (3-ethyl-3-oxetanylmethoxy) hexane, 1,4-bis (3-ethyl-3-oxetanylmethoxy) -2-butene, 1,4-bis (3-ethyl-3-oxetanylmethoxy) ) Methylcyclohexane and 1,4-bis (3
-Ethyl-3-oxetanylmethoxy) methylbenzene, 4,4'-bis (3-ethyl-3-oxetanylmethoxy) methylbiphenyl, 4,4'-bis (3-methyl-3-oxetanylmethoxy) methylbiphenyl, etc. No.

The diether bisoxetanes are synthesized, for example, by reacting the corresponding dibromide (xylylene dibromide, ethylene dibromide, etc.) with 3-alkyl-3-hydroxymethyloxetane.

The polyether bisoxetanes include, for example, diethylene glycol bis (3-ethyl-3-oxetanylmethyl) ether, triethylene glycol bis (3-ethyl-3-oxetanylmethyl) ether, tetraethylene glycol bis ( 3-ethyl-3-oxetanylmethyl) ether and the like. The polyether bisoxetanes are synthesized, for example, by reacting the corresponding polyethylene glycol (diethylene glycol, triethylene glycol, tetraethylene glycol, etc.) with p-toluenesulfonyl chloride of 3-alkyl-3-hydroxymethyloxetane. Is done.

Among the above ether type bisoxetane compounds, bis (3-ethyl-3-oxetanyl) methyl ether, 1,2-bis (3-ethyl-3-oxetanylmethoxy) ethane, 1,4-bis (3 -Ethyl-3-oxetanylmethoxy) methylbenzene, 4,4'-bis (3-ethyl-3-oxetanylmethoxy) methylbiphenyl and the like are particularly preferred.

[Coupling Agent] As the coupling agent used in the present invention, any coupling agent capable of chemically bonding the oxetane compound to the surface of an adherend (particularly, an inorganic material such as glass) can be used. Any material can be used. Among them, a silane coupling agent capable of chemically bonding the oxetane compound to the inorganic material is preferable. Examples of such a silane coupling agent include a reactive group (alkoxysilyl group, silanol, etc.) that chemically bonds to an inorganic material and a reactive group that chemically bonds to or has an affinity for the oxetane compound (vinyl group, epoxy group, amino group, etc.). And a methacryl group) are preferred. For example, KBM-303, KBM-40
3 (above, manufactured by Shin-Etsu Chemical), AL-M, KR-TTS (above, manufactured by Ajinomoto) and the like.

[Photopolymerization Initiator] As the photopolymerization initiator used in the present invention, a compound capable of generating a cation by ultraviolet irradiation to initiate ring-opening of the oxetane ring and cationic polymerization is preferably exemplified. As such a compound, an onium salt capable of releasing a Lewis acid represented by the following formula is preferable.

[0018]

Embedded image (Where Q is S, Se, Te, P, As, Sb, B
i, Fe, O, I, Br, Cl, or N≡N;
³ , R ⁴ , R ⁵ and R ⁶ represent the same or different organic groups. M is a metal or metalloid constituting the central atom of the anion portion of the above formula, and for example, B, P, As, Sb, Fe, S
n, Bi, Al, Ca, In, Tl, Zn, Sc, V,
Represents Cr, Mn, or Co. X represents a halogen atom. a, b, c, and d represent an integer of 0 to 3, and a + b + c
+ D equals the valency of M and m equals the valency of M. The organic group includes an aryl group and the like, and the halogen atom includes F, Cl, Br and the like. )

As the cation (onium ion) in the above formula, for example, diphenyliodonium ion, bis (4-methoxyphenyl) iodonium ion, bis (4-methylphenyl) iodonium ion,
Bis (4-t-butylphenyl) iodonium ion,
Iodonium ions such as bis (dodecylphenyl) iodonium ion, triphenylsulfonium ion,
Sulfonium such as diphenyl-4-thiophenoxyphenylsulfonium ion, bis [4- (diphenylsulfonio) phenyl] sulfide ion, and bis [4- (di (4- (2-hydroxyethyl) phenyl) sulfonio) phenyl] sulfide ion ions and, η ⁵ -2,
4- (cyclopentadienyl) [(1,2,3,4,
5,6-η)-(methylethyl) benzene] -iron (1
+) Ions and the like.

The anion [MX _{m + k} ] ^-k in the above formula is, for example, a tetrafluoroborate ion (BF
₄ ^-), hexafluorophosphate ion (PF ₆ ^-),
Examples include hexafluoroantimonate ion (SbF ₆ ⁻ ), hexafluoroarsenate ion (AsF ₆ ⁻ ), and hexachloroantimonate ion (SbCl ₆ ⁻ ).

Further, perchlorate ion (ClO ₄ ⁻ ), trifluoromethanesulfonic acid ion (CF ₃ SO ₃ ⁻ ), fluorosulfonic acid ion (FSO ₃ ⁻ ), toluenesulfonic acid ion (CH ₃ C ₆ H ₅ SO 4) ₃ ^-), trinitrobenzene sulfonic acid ion, and also such as trinitrotoluene sulfonate ion.

Further, as the photopolymerization initiator of the present invention, an aromatic onium salt can also be used. For example, aromatic halonium salts (see Japanese Patent Application Laid-Open Nos. 50-151996 and 50-158680) and aromatic onium salts VIA (Japanese Patent Laid-Open Nos. 50-151997 and 52-30899). JP-A-56-55420, JP-A-55-125105, etc.), VA
Aromatic onium salts (see, for example, JP-A-50-158699) and oxosulfoxonium salts (see JP-A-56-15898).
149402, JP-A-57-192429, etc.), aromatic diazonium salts (JP-A-49-17)
040) and thiopyrylium salts (U.S. Pat. No. 4,139,655). Also,
An iron / allene complex, an aluminum complex / photolytic silicon compound-based initiator and the like can also be mentioned as the photopolymerization initiator of the present invention.

Commercially available photopolymerization initiators include, for example,
Thyracure UVI-6974 (a mixture of bis [4- (diphenylsulfonio) phenyl] sulfide bishexafluoroantimonate and diphenyl-4-thiophenoxyphenylsulfonium hexafluoroantimonate), Cyracure UVI-6990 (UVI-69
74 hexafluorophosphate) (all manufactured by Union Carbide), Adeka Optomer SP-151, and Adeka Optomer SP-170 (bis [4- (di (4-
(2-Hydroxyethyl) phenyl) sulfonio) phenyl] sulfide), adecaoptomer SP-150
(Hexafluorophosphate of SP-170), ADEKA OPTOMER SP-171 (all manufactured by Asahi Denka),

DTS-102, DTS-103, NAT
-103, NDS-103 ((4-hydroxynaphthyl) -dimethylsulfonium hexafluoroantimonate), TPS-102 (triphenylsulfonium hexafluorophosphate), TPS-103 (triphenylphosphonium hexafluoroantimonate),
MDS-103 (4-methoxyphenyl-diphenylsulfonium hexafluoroantimonate), MPI-
103 (4-methoxyphenyliodonium hexafluoroantimonate), BBI-101 (bis (4-t
-Butylphenyl) iodonium tetrafluoroborate), BBI-102 (bis (4-t-butylphenyl) iodonium hexafluorophosphate), BB
I-103 (bis (4-t-butylphenyl) iodonium hexafluoroantimonate) (all manufactured by Midori Kagaku) and

Irgacure 261 (η ⁵ -2,4-
Cyclopentadien-1-yl) [(1,2,3,4,
5,6-η)-(1-methylethyl) benzene] -iron (1+) hexafluorophosphate (1-)) (manufactured by Ciba-Geigy), CD-1010, CD-1011, C
D-1012 (4- (2-hydroxytetradecanyloxy) diphenyliodonium hexafluoroantimonate) (all manufactured by Sartomer), SI-60L, S
I-100L, SI-180L (manufactured by Sanshin Chemical)
And

CI-2481, CI-2624, CI-
2639, CI-2064 (all manufactured by Nippon Soda), D
egacure K126 (bis [4- (diphenylsulfonio) phenyl] sulfide bishexafluorophosphate) (manufactured by Degussa) and RHODORSIL
PHOTOINITIATOR 2074 ((tricumyl) iodonium tetrakis (pentafluorophenyl) borate) (manufactured by Rhodia) may be used.

Of these, UVI-6974, UVI-6
990, Adeka Optomer SP-170, Adeka Optomer SP-171, CD-1013 and MPI-103 can be preferably used, and UVI-6990 is particularly preferable.

[UV-curable adhesive composition] The UV-curable adhesive composition of the present invention comprises the oxetane compound described above,
It comprises a coupling agent and a photopolymerization initiator. In this composition, the coupling agent is used in an amount of 0.1 to 10 parts by weight, more preferably 2 to 10 parts by weight, based on 100 parts by weight of the oxetane compound.
Preferably, the photopolymerization initiator is contained in an amount of 0.1 to 1 part by weight based on 100 parts by weight of the oxetane compound.
0 parts by weight, more preferably 0.5 to 6 parts by weight.

That is, as the ultraviolet-curable adhesive composition of the present invention, 0.1 to 10 parts by weight of a coupling agent and 0.1 to 10 parts by weight of a photopolymerization initiator are used for 100 parts by weight of an oxetane compound. (A) is preferable, and (B) more preferably contains 2 to 10 parts by weight of a coupling agent and 0.5 to 6 parts by weight of a photopolymerization initiator with respect to 100 parts by weight of an oxetane compound. .

Further, the ultraviolet-curable adhesive composition of the present invention preferably contains one or more alicyclic epoxy compounds in addition to the coupling agent. Although the content ratio is not particularly limited, it is 1 to 200 parts by weight, more preferably 5 to 100 parts by weight, based on 100 parts by weight of the oxetane compound.
It is preferably about 100 parts by weight.

As the alicyclic epoxy compound, for example,
UVR-6110, UVR-6128 (above, UCC
Made), celloxide 2021, celloxide 2081,
Commercially available products such as Celloxide 3000 (all manufactured by Daicel) can be used.

The ultraviolet-curable adhesive composition of the present invention preferably further contains one or more modified silicone oils. The content ratio is preferably 0.1 to 10 parts by weight based on 100 parts by weight of the oxetane compound.

Examples of the modified silicone oil include reactive silicone oils (amino-modified, epoxy-modified, carboxyl-modified, carbinol-modified, methacryl-modified, phenol-modified, one-terminal-modified, heterofunctional-group-modified, etc.).
And non-reactive silicone oils (polyether modified, methylstyryl modified, alkyl modified, higher fatty acid modified, hydrophilic special modified, higher alkoxy modified, higher fatty acid containing,
Fluorine-modified one) can be used. Specifically, KF-105 is used as a reactive silicone oil.
Non-reactive silicone oils such as KF-303 and FL-100 (Shin-Etsu Chemical)
And the like are preferably used.

That is, the ultraviolet-curable adhesive composition of the present invention has the above-mentioned composition (A) or (B), and the alicyclic epoxy compound is added to 100 parts by weight of the oxetane compound. Those further containing 1 to 200 parts by weight are preferred. Further, the composition further has the composition of (A) or (B), and the alicyclic epoxy compound is added in an amount of 1 to 200 parts by weight with respect to 100 parts by weight of the oxetane compound.
Those containing 0.1 to 10 parts by weight of the modified silicone oil are particularly preferred. The ultraviolet-curable adhesive composition of the present invention is prepared, for example, by blending each component in the air at room temperature, but the conditions are not particularly limited as long as it is not irradiated with ultraviolet light.

The method of using the ultraviolet-curable adhesive composition of the present invention is not particularly limited. For example, the composition may be applied to a first adherend and then adhered to a second adherend. Alternatively, the first and second adherends can be laminated, and the composition can be permeated into the gap between them, and then cured by irradiation with ultraviolet light to be used as an adhesive.

As the adherend, an inorganic material (particularly, glass) is preferable. That is, the ultraviolet-curable adhesive composition of the present invention is useful for inorganic materials (particularly for glass). The adherend can be selected from glass, cement mortar, concrete, ceramics (including films, plates, molded parts, and other shaped products), iron, stainless steel, aluminum, other metals, alloys, etc.
At least one of them must be able to transmit ultraviolet light. Glass is preferable as the adherend capable of transmitting ultraviolet rays, but the type and thickness are not particularly limited as long as the transmission of ultraviolet rays is not hindered.

The ultraviolet irradiation is preferably performed at a wavelength of about 200 to 400 nm and in an irradiation amount of about 10 to 3000 mJ / cm ² , more preferably about 50 to 1000 mJ / cm ² . For example, using an ultraviolet lamp of 120 W / cm, an irradiation distance of 11 cm, and 0.7 to 3.5 m / m
Irradiation may be performed at an in feed speed. The temperature at this time is not particularly limited as long as the curing of the composition is not hindered, and may be usually room temperature.

Examples of the ultraviolet light source include a mercury arc lamp, a xenon arc lamp, a fluorescent lamp, a carbon arc lamp, a tungsten-halogen copying lamp, a sodium lamp, and an alkali metal lamp. These light sources are about 185-400 nm, and even about 240-400 nm.
A tube having a tube that transmits light having a wavelength of nm is preferable, but a tube having a tube made of quartz or Pyrex (registered trademark) may be used.

[0039]

Next, the present invention will be described specifically with reference to examples and comparative examples. However, the evaluation of the ultraviolet-curable adhesive composition was performed as follows.

(1) Shear strength As shown in FIG. 1, glass (slide glass; about 1 thickness)
mm × 25 mm) as the adherend. That is, a Teflon (registered trademark) adhesive tape (thickness: 150 μm × width: about 1 mm) is attached as a spacer to both ends of the slide glass, and about 5 mm from the end of the slide glass is overlapped and fixed with a clip. UV-curable adhesive composition was allowed to penetrate into the substrate, and was cured by irradiating UV rays with the UV irradiator (adhesive area 5).
× 25 mm ² ). Next, a steel plate was bonded to the glass test piece using an epoxy resin and reinforced, and the steel plate portion was sandwiched with a chuck, and a 180 ° shear strength was measured at a tensile strength of 5 mm / min using a Tensilon tensile tester.

The ultraviolet irradiation was performed using a UVC-1212 type UV irradiation device of Unicure System manufactured by Ushio Inc. (output: 1.
5 kw, UV lamp output: 120 W / cm, with a cold filter) at an irradiation distance of 11 cm and a conveyor speed of 2.5 m / min. In the measurement of the shear strength, irradiation was performed three times in the order of front, back, and front.

(2) Curing Speed The ultraviolet curable adhesive composition was applied to a slide glass and irradiated with ultraviolet rays, and the number of irradiations until the cured product no longer tacked was measured.

(3) Pencil Hardness An ultraviolet-curable adhesive composition is applied to a slide glass and irradiated with ultraviolet light to determine the hardness of the cured product (coating film) according to JIS K54.
It was evaluated by a pencil hardness test based on 00.

Examples 1 to 3 An oxetane compound, a coupling agent, a modified silicone oil, and a photopolymerization initiator were blended to prepare a liquid ultraviolet ray curable adhesive composition having the composition shown in Table 1. Next, the shear strength of each composition was measured by the above method. In the table, the numerical value of each component of the composition is in units of g (hereinafter, referred to as g).
Similar). As a result, all the compositions of the present invention had high shear strength (Table 1).

Comparative Examples 1 and 2 Liquid ultraviolet curable adhesive compositions were prepared in the same manner as in Examples 1 to 3 except that the compositions were changed as shown in Table 1, and the shear strength of each composition was measured. It was measured. As a result, those containing no coupling agent or oxetane compound had low shear strength and easily peeled off the glass (Table 1).

[0046]

[Table 1]

Examples 4 and 5 A liquid ultraviolet curable adhesive composition further containing an alicyclic epoxy compound was prepared in the same manner as in Example 2 except that the composition was changed as shown in Table 2. The shear strength of each composition was measured. Further, the curing speed and the pencil hardness including the composition of Example 2 were separately measured. As a result, the shear strength was significantly improved by further containing the alicyclic epoxy compound (Table 2). Further, the curing speed and the hardness of the cured product were improved (Table 2).

[0048]

[Table 2]

Examples 6 to 8 A liquid ultraviolet curable adhesive composition was prepared in the same manner as in Example 1 except that the composition was changed as shown in Table 3 (the type of the oxetane compound was changed). The shear strength of each composition was measured. As a result, all the compositions of the present invention had high shear strength (Table 3).

Examples 9 to 15 In the same manner as in Example 1, except that the composition was changed as shown in Table 3 (the type of the oxetane compound was changed to further contain an alicyclic epoxy compound). Liquid ultraviolet-curable adhesive compositions further containing an epoxy compound were prepared, and the shear strength of each composition was measured. As a result, all the compositions of the present invention had high shear strength (Table 3).

[0051]

[Table 3]

[0052]

According to the present invention, it is possible to provide an ultraviolet-curable adhesive composition which is excellent in adhesive strength (shear strength) and curing speed and gives a cured product having high hardness. The ultraviolet-curable adhesive composition of the present invention is particularly useful when an inorganic material (particularly glass) is used as an adherend.

[Brief description of the drawings]

FIG. 1 is a schematic view of a test piece when measuring shear strength.

Claims (5)

[Claims] 1. An ultraviolet-curable adhesive composition comprising an oxetane compound, a coupling agent, and a photopolymerization initiator. 2. The ultraviolet-curable adhesive according to claim 1, comprising 0.1 to 10 parts by weight of a coupling agent and 0.1 to 10 parts by weight of a photopolymerization initiator based on 100 parts by weight of the oxetane compound. Composition. 3. The ultraviolet-curable adhesive composition according to claim 1, further comprising an alicyclic epoxy compound. 4. The ultraviolet-curable adhesive composition according to claim 1, further comprising a modified silicone oil. 5. The ultraviolet-curable adhesive composition according to claim 1, wherein the oxetane compound is an ether-type bisoxetane compound.