Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Compositions to be polymerized by wave energy wherein said...
Reexamination Certificate
1996-10-11
2003-01-07
Berman, Susan W. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Compositions to be polymerized by wave energy wherein said...
C522S017000, C522S018000, C522S024000, C522S029000, C522S173000, C522S012000, C522S020000, C522S023000, C522S028000, C430S281100
Reexamination Certificate
active
06503959
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a cyanoacrylate composition having photocurability. Possible applications of the composition include lithography, potting, molding, coating, adhesives, sealing materials, and various resist materials.
BACKGROUND OF THE INVENTION
&agr;-Cyanoacrylate adhesives are extensively utilized as cold-setting single-liquid type instantaneous adhesives for metals, plastics, rubbers, woods, etc., because they rapidly polymerize and cure by the action of a minute amount of the adsorption water present on adherend surfaces to extremely tenaciously bond the adherends to each other in a short time period.
However, the &agr;-cyanoacrylate adhesives have a drawback that the curing is very slow when the gap between adherends is wide, when the adhesive applied has overflown from the bonding part, or when the adhesive applied is not sandwiched between a pair of adherends as in coating.
In general, a cyanoacrylate adhesive with which a large gap is filled or which has overflown from a bonding part is cured by using a primer or a curing accelerator. However, not only this technique is troublesome, but also the basic compound used as the main component of the primer or curing accelerator and the odor of the solvent contained therein are undesirable for the working environment.
There is hence a desire for a cyanoacrylate adhesive which can be easily cured without impairing the excellent features of the instantaneous adhesive, i.e., cold-setting and single-liquid type.
To eliminate the problem described above, cyanoacrylate adhesive compositions having photocurability have been proposed. For example, a cyanoacrylate adhesive composition containing a radical-generating photopolymerization initiator is disclosed in JP-A-62-57475. (The term “JP-A” as used herein means an “unexamined published Japanese patent application.”)
JP-A-6-299122 discloses an adhesive composition containing an aromatic azide compound as a photoinitiator for anionic polymerization.
WO93/10483 discloses a technique in which an inorganic chromium complex is used as a photoinitiator for anionic polymerization.
Further, a technique of using Pt(acac)
2
as a photoinitiator for anionic polymerization is reported in
Macromolecules
, 28 (4) 1328 (1995).
These proposed compositions, however, have problems such as the following. In order for the compositions to cure, a relatively long light irradiation time of from 1 to 2 minutes is necessary. In the case of radical polymerization, the curing reaction is inhibited by oxygen and, as a result, the adhesive surface suffers curing failure or remains tacky. Moreover, the compositions foam upon light irradiation, or have poor storage stability.
On the other hand, many proposals have been made on photocurable compositions containing a metallocene compound as a photoinitiator. Metallocene compounds are generally used as a photoinitiator for radical polymerization or cationic polymerization. For example, JP-A-6-35189 discloses a photopolymerizable mixture containing a photoinitiator comprising (A) a photoreducible dye, (B) a radiation-decomposable trihalomethyl compound, and (C) a metallocene compound and a recording material produced from the mixture.
JP-A-5-117311 discloses a photopolymerization initiator comprising a complex obtained by the interaction of (A) a charge-transfer complex comprising a biscyclopentadienyliron derivative and a quinoid compound with (B) at least one salt selected from the group consisting of tetrafluoroboric acid salts, hexafluorophosphoric acid salts, and hexafluoroantimonic acid salts.
JP-A-4-221958 discloses a photopolymerizable mixture containing a metallocene compound as a photoreaction initiator and a recording material produced from the mixture.
JP-A-2-127404 discloses a photopolymerizable mixture containing a photoinitiator comprising (A) a photo-reducible dye, (B) a radiation-decomposable trihalomethyl compound, and (C) a metallocene compound and a recording material produced from the mixture.
JP-A-4-73763 discloses a photocurable electrodeposition coating composition containing a titanocene compound as an initiator.
Further, a technique of photocuring a vinyl monomer by means of ferrocene alone or a combination thereof with carbon tetrachloride is reported in
J. Macromol. Sci.-Chem
., A28 (5&6), 557 (1991).
However, the techniques shown above are based on a polymerization mechanism in which a radical or cationic polymerization reaction proceeds, and are unrelated to the technique for photopolymerizing and curing an &agr;-cyanoacrylate mainly by anionic polymerization, in particular to the technique of the present invention.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a photocurable composition having excellent photocurability to overcome the above-described problems in the prior art.
The present inventors have found that the above object is achieved with the following embodiments:
(1) a photocurable composition comprising:
(A) an &agr;-cyanoacrylate and
(B) a metallocene compound comprising a transition metal of Group VIII of the periodic table and aromatic electron system ligands;
(2) the photocurable composition according to the embodiment (1), further comprising (C) a cleavage-type photoinitiator;
(3) the photocurable composition according to the embodiment (1) or (2), wherein in the metallocene compound (B) comprising a transition metal of Group VIII of the periodic table and aromatic electron system ligands, the aromatic electron system ligands each is a &pgr;-arene, indenyl, or &eegr;-cyclopentadienyl;
(4) the photocurable composition according to any one of the embodiments (1) to (3), wherein the metallocene compound (B) comprising a transition metal of Group VIII of the periodic table and aromatic electron system ligands is represented by the following formula (I):
(wherein M represents a transition metal of Group VIII of the periodic table; R represents a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, a halogenated hydrocarbon group having 1 to 20 carbon atoms, or a silicon atom-containing, oxygen atom-containing, sulfur atom-containing, or phosphorus atom-containing group having 1 to 20 carbon atoms, provided that the R's may be the same or different and may be crosslinked to each other; symbol a represents an integer of from 0 to 5; and the groups [R
a
-Cp] (Cp represents &eegr;-cyclopentadienyl) may be the same or different);
(5) the photocurable composition according to any one of the embodiments (1) to (4), wherein in the metallocene compound (B) comprising a transition metal of Group VIII of the periodic table and aromatic electron system ligands, the transition metal of Group VIII of the periodic table comprises iron, osmium, ruthenium, cobalt, or nickel; and
(6) the photocurable composition according to the embodiment (5), wherein in the metallocene compound (B) comprising a transition metal of Group VIII of the periodic table and aromatic electron system ligands, the transition metal of Group VIII of the periodic table comprises iron, osmium, or ruthenium.
The photocurable composition of the present invention can be rapidly cured by light irradiation even when the gap between a pair of adherends is wide, when the composition applied has overflown from the bonding part, or when the composition applied is not sandwiched between a pair of adherends as in coating. Since the curing reaction proceeds by anionic polymerization, not only the composition does not suffer the surface curing inhibition by oxygen which is observed in radical polymerization, but also even that part of the composition which light cannot reach due to the shape of the substrate cures by the anionic polymerization initiated by light irradiation. Further, since the metallocene compound has a light absorption wavelength region extending beyond 500 nm to the longer-wavelength side, the composition can be cured with a light in a wider wavelength region, i.e., even with ultraviolet and/or visible light.
DETAILED DESCRIPTION OF THE INVENTION
This invention is explain
Mikuni Hiroyuki
Nishiyama Yuko
Berman Susan W.
Sughrue & Mion, PLLC
Three Bond Co. Ltd.
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