Organic compounds -- part of the class 532-570 series – Organic compounds – Four or more ring nitrogens in the bicyclo ring system
Reexamination Certificate
1997-09-30
2003-12-30
Qazi, Sabiha (Department: 1616)
Organic compounds -- part of the class 532-570 series
Organic compounds
Four or more ring nitrogens in the bicyclo ring system
C428S064100, C428S064400, C428S064800
Reexamination Certificate
active
06670475
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to an information recording medium on which information can be recorded by means of a laser beam having a high energy density, and a dye compound which is favorably utilized for preparing the information recording medium.
BACKGROUND OF THE INVENTION
The recordable compact disc (CD-R), on which information can be recorded only once, is widely used, for instance, as a large capacity computer data disc.
The optical disc of CD-R type generally comprises a disc-shaped substrate (support) and a recording layer provided thereon. The disc substrate comprises a transparent material such as synthetic resin. The recording layer comprises a metal or a semi-metal such as Bi, Sn, In or Te, or alternatively a dye such as a cyanine dye, a metal-complex dye, or a quinone dye. A light-reflecting layer and a protective layer may be superposed in order on the recording layer. The light-reflecting layer and the protective layer can be made of gold and resin, respectively.
On the CD-R, the writing (recording) and reading (reproducing) can be performed in the following manner. The laser beam (usually used wavelength is 780 nm) modulated by information is applied to the recording layer of the CD-R through the substrate. The recording layer alters its optical characteristics in the area where the laser beam has been applied, to produce a chemical or physical change such as production of pit. The reading of the recorded information can be performed by sequentially applying a laser beam on the recording layer of the CD-R through the substrate and detecting a light reflected on the CD-R.
At present, most of the recording layer of CD-R utilizes a light-sensitive dye as the recording material, because the recording dye layer can be easily formed by a coating method and shows a high sensitivity, as compared with the recording metal layer. However, the dye layer has such disadvantages as low light-resistance and low heat resistance. Therefore, it has been desired to develop a recording layer having high durability against light and heat, as well as having high recording and reproducing characteristics.
Japanese Patent Provisional Publication No. 63-209995 describes an optical disc which has a recording layer comprising an oxonol dye. According to the description of publication, such optical disc maintains stable recording and reproducing characteristics for a long time. The publication discloses an oxonol dye compound having an ammonium ion in the form of an inner salt.
The inventors have found that the optical disc having the recording layer of the above oxonol dye exhibits insufficient light-resistance, while the disc has relatively improved characteristics in view of heat resistance and durability for repeated reproducing. Therefore, such optical disc often causes troubles in reproducing process after long exposure to light such as sunlight.
Accordingly, it is an object of the present invention to provide an information recording medium having stable recording characteristics and particularly high light-resistance to maintain satisfactory recording characteristics for a long time.
It is another object of the present invention to provide a new oxonol dye compound favorably employable for preparing the information recording medium having stable recording characteristics.
SUMMARY OF THE INVENTION
The present invention resides in an information recording medium comprising a support and a recording layer provided thereon on which information can be recorded by means of a laser beam, wherein said recording layer contains a dye compound having the below-mentioned formula (I-1) or (I-2):
in which each of A
1
, A
2
, B
1
and B
2
independently represents a substituent group; each of Y
1
and Z
1
independently represents a group of atoms required for forming a carbon ring or a heterocyclic ring; each of E and G independently represents a group of atoms required for forming a conjugated double bond chain; X
1
represents ═O, ═NR or ═C(CN)
2
, wherein R is a substituent group; X
2
represents —O, —NR or —C(CN)
2
, wherein R is a substituent-group; each of L
1
, L
2
, L
3
, L
4
and L
5
independently represents a methine group which may have a substituent group; M
k+
represents an onium ion containing a positively charged onium atom to which no hydrogen atom is attached; each of m and n independently is an integer of 0, 1 or 2; each of x and y independently is an integer of 0 or 1; and k is an integer of 1 to 10.
The invention further resides in a new oxonol compound having the below-mentioned formula (IV-1) or (IV-2):
in which each of A
3
, A
4
, B
3
and B
4
independently represents a substituent group selected from the group consisting of a linear, branched or cyclic alkyl group having 1 to 18 carbon atoms, an alkenyl group having 2 to 18 carbon atoms, an alkynyl group having 2 to 18 carbon atoms, an aryl group having 6 to 18 carbon atoms, an aralkyl group having 7 to 18 carbon atoms, an acyl group having 2 to 18 carbon atoms, an alkylsulfonyl group having 1 to 18 carbon atoms, an arylsulfonyl group having 6 to 18 carbon atoms, an alkylsulfinyl group having 1 to 18 carbon atoms, an alkoxycarbonyl group having 2to 18 carbon atoms, an aryloxycarbonyl group having 7 to 18 carbon atoms; an alkoxy group having 1 to 18 carbon atoms, an aryloxy group having 6 to 18 carbon atoms, an alkylthio group having 1 to 18 carbon atoms, an arylthio group having 6 to 10 carbon atoms, an acyloxy group having 2 to 18 carbon atoms, a sulfonyloxy group, a carbamoyloxy group, an amino group, a carbamoyl group, a sulfamoyl group, a halogen atom, a hydroxyl group, a nitro group, a cyano group, a carboxyl group, and a 4- to 7-membered heterocyclic group, wherein these substituent groups may be substituted with at least one group selected from those consisting of the above-mentioned substituent groups;
each of Y
2
and Z
2
independently represents a group of atoms required for forming a 4- to 7-membered carbon ring or a 4- to 7-membered heterocyclic ring, which may be substituted with at least one group selected from those consisting of the substituent groups described for A
3
, A
4
, B
3
and B
4
and may be fused with a 4- to 7-membered carbon ring or a 4- to 7-membered heterocyclic ring;
each of L
6
, L
7
, L
8
, L
9
and L
10
independently represents a methine group which may have one or two substituent groups selected from the group consisting of the substituent groups described for A
3
, A
4
, B
3
and B
4
;
M
2+
represents a quaternary ammonium ion; and
each of m1 and n1 independently represents an integer of 0, 1 or 2.
In contrast to the known oxonol dye compounds, the new oxonol dye compound of the invention comprises an onium salt in which an onium atom has no hydrogen atoms thereon (quaternary ammonium salt is particularly preferred). The inventors have found that the new oxonol dye compound enhances light-resistance to provide the information recording medium.
DETAILED DESCRIPTION OF THE INVENTION
The preferred embodiments of the invention are as follows:
(1) M
k+
in the formula (I-1) or (I-2) is a quaternary ammonium ion.
(2) k in the formula (I-1) or (I-2) is an integer of 0 to 4.
(3) k in the formula (I-1) or (I-2) is 2.
(4) M
k+
is an onium ion of the below-mentioned formula (II):
in which each of R
1
and R
2
independently represents a group selected from the group consisting of an alkyl group, an alkenyl group, an alkynyl group, an aryl group or a heterocyclic group; each of R
3
and R
4
independently represents a substituent group; or each set of R
1
and R
3
, R
2
and R
4
, or R
3
and R
4
can be combined to form a ring; each of q1 and r1 independently is an integer of 0 to 4; provided that plural R
3
and plural R
4
are the same as or different from each other in the case that q1 and r1 are 2 or more, respectively.
(5) M
k+
is an onium ion of the below-mentioned formula (III):
in which each of R
5
and R
6
independently represents a group selected from the group consisting of an alkyl group, an alkenyl group, an alk
Ishida Toshio
Morishima Shinnichi
Wariishi Koji
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