ADHESIVE COMPOSITION AND OPTICAL FILTER
To provide an adhesive composition which is prevented from change in color and color degradation after the moisture resistance test in a state where a copper mesh is bonded. Further, to provide an optical filter which is excellent in moisture resistance and which is prevented from change in color and color degradation. The adhesive composition of the present invention is an adhesive composition (first adhesive 14 ) to bond a copper mesh 12 to an adherend (antireflection film 11 ), and contains an acrylic adhesive having an acid value of at most 7 mgKOH/g and a dye containing no hydroxyl group nor amino group. In the adhesive composition of the present invention, the dye is preferably at least one dye selected from the group consisting of an anthraquinone dye and a porphyrin dye. The optical filter 10 of the present invention comprises a copper mesh 12 bonded to an adherend (antireflection film 11 ) by means of the above adhesive composition (first adhesive 14 ).
1 . An adhesive composition for bonding a copper mesh to an adherend, comprising an acrylic adhesive having an acid value of at most 7 mgKOH/g and a dye containing no hydroxyl group nor amino group.
2 . The adhesive composition according to claim 1 , which contains, as a dye, substantially only the dye containing no hydroxyl group nor amino group.
3 . The adhesive composition according to claim 1 , wherein the dye containing no hydroxyl group nor amino group is at least one dye selected from the group consisting of an anthraquinone dye and a porphyrin dye.
4 . The adhesive composition according to claim 3 , wherein the anthraquinone dye is a compound of the is formula (1) or (2):
wherein each of R 1 to R 8 which are independent of one another, is a hydrogen atom, a chlorine atom, a fluorine atom, a bromine atom, a cyano group, a benzyl group, a C 1-12 alkyl group (provided that the hydrogen atom in the alkyl group may be substituted by a fluorine atom or a chlorine atom), a phenyl group (provided that the hydrogen atom in the phenyl group may be substituted by a fluorine atom or a chlorine atom), a C 1-12 alkoxyl group (provided that the hydrogen atom may be substituted by a fluorine atom or a chlorine atom), —CO—R a (wherein R a is a C 1-8 alkyl group, a phenyl group, a benzyl group, a cyclohexyl group, a cyclohexylmethyl group, a 1-naphthyl group or a 2-naphthyl group), —S—R b (wherein R b is a C 1-8 alkyl group, a phenyl group, a benzyl group, a cyclohexyl group, a cyclohexylmethyl group, a 1-naphthyl group or a 2-naphthyl group), or —NH-Ph (wherein Ph is a phenyl group, and the hydrogen atom in the phenyl group may be substituted by a C 1-10 alkyl group or a C 1-10 alkoxyl group);
wherein each of R 9 to R 22 which are independent of one another, is a hydrogen atom, a chlorine atom, a fluorine atom, a bromine atom, a cyano group, a benzyl group, a C 1-12 alkyl group (provided that the hydrogen atom in the alkyl group may be substituted by a fluorine atom or a chlorine atom), a phenyl group (provided that the hydrogen atom in the phenyl group may be substituted by a fluorine atom or a chlorine atom), a C 1-12 alkoxyl group (provided that the hydrogen atom in the alkoxyl group may be substituted by a fluorine atom, a bromine atom or a chlorine atom), —CO—R c (wherein R c is a C 1-8 alkyl group, a phenyl group, a benzyl group, a cyclohexyl group, a cyclohexylmethyl group, a 1-naphthyl group or a 2-naphthyl group), —S—R d (wherein R d is a C 1-8 alkyl group, a phenyl group, a benzyl group, a cyclohexyl group, a cyclohexylmethyl group, a 1-naphthyl group or a 2-naphthyl group), or —NH-Ph (wherein Ph is a phenyl group, and the hydrogen atom in the phenyl group may be substituted by a C 1-10 alkyl group or a C 1-10 alkoxyl group).
5 . The adhesive composition according to claim 3 , wherein the porphyrin dye is a compound of the formula (3):
wherein each of R 23 to R 30 which are independent of one another, is a hydrogen atom, a chlorine atom, a fluorine atom, a bromine atom, a cyano group, a benzyl group (provided that the hydrogen atom in the benzyl group may be substituted by a fluorine atom, a bromine atom or a chlorine atom), a phenyl group (provided that the hydrogen atom in the phenyl group may be substituted by a fluorine atom, a bromine atom or a chlorine atom), a C 1-10 alkyl group (provided that the hydrogen atom in the alkyl group may be substituted by a fluorine atom, a bromine atom or a chlorine atom), or a C 1-10 alkoxyl group (provided that the hydrogen atom in the alkoxyl group may be substituted by a fluorine atom or a chlorine atom), is and M is Cu, Ni, Zn, Pd, Pt, VO, Co or Mg.
6 . The adhesive composition according to claim 1 , wherein the acrylic adhesive having an acid value of at most 7 mgKOH/g, is an adhesive containing (meth)acrylic acid or its alkyl ester as the main component.
7 . An optical filter having a copper mesh bonded to an adherend by means of the adhesive composition as defined in claim 1 .
8 . The optical filter according to claim 7 , wherein the adherend is an antireflection film.
9 . The optical filter according to claim 7 , wherein the adherend is a resin film.