Polyazo compound or salt thereof and dye-based polarization...

Details Polyazo compound or salt thereof and dye-based polarization... Polyazo compound or salt thereof and dye-based polarization...

2001-11-23

2002-06-04

Powers, Fiona T. (Department: 1626)

Organic compounds -- part of the class 532-570 series

Organic compounds

Azo

C534S811000, C534S812000, C534S819000, C534S669000, C252S585000, C359S491010

Reexamination Certificate

active

06399752

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to a polyazo compound or a salt thereof, and a dye-based polarization film containing the same.
Polarization films are produced by adding iodine and dichromatic dye as a polarization element into a polarization film substrate such as a drawn and oriented polyvinyl alcohol-based film, an oriented polyene-based film produced by de-hydrochloric acid of a polyvinyl chloride film or dehydration of a polyvinyl alcohol film, and the like. Among them, iodine-based polarization films manifest a problem of decrease in abilities thereof under high temperature and high humidity conditions, since they have poor endurance to heat and poor endurance to water though they are excellent in the initial polarization ability. Some methods are studied for enhancing such endurances, such as a method in which treatment is effected with an aqueous solution containing formaldehyde or boric acid, a method In which a polymer film having low water vapor permeability is used as a protective film, and the like,. However, these methods are not sufficient yet.
On the other hand, dye-based polarization films using a dichromatic dye as a polarization element generally poor In initial polarization ability though they art excellent in endurance to heat and water as compared with iodine-based polarization films. Therefore, there is a desire for polyazo dyes used in a polarization film excellent in the initial polarization ability.
The present inventors have investigated dyes which have excellent dyeing property in producing a polarization film, are excellent in polarization ability. durability under high temperature and high humidity conditions and light resistance, and cover a region of from 500 to 580 nm in a polarization film used for a liquid crystal projector and the like, the polarization film being obtained by orientation and adsorption of a dichromatic dye in a polymer film, Resultantly, they have found that a specific polyazo compound or salt thereof attains the above-mentioned object. Thus, the present invention was completed.
SUMMARY OF THE INVENTION
Namely, the present Invention provides a polyazo compound or salt thereof of the following formula (I):
wherein,
A represents a naphthyl having 1 to 3 sulfos or a phenyl having 1 to 2 hydrophilic groups selected from sulfo and carboxyl and optionally having a lower alkyl or lower alkoxy,
B represents —NHCO— or —N═N—,
n represents 0 or 1, provided that, when B represents —N═N—, n represents or
R
1
to R
6
are the same or different and represent hydrogen, lower alkyl or lower alkoxy, provided that, when n represents 0, R
1
to R
4
represent hydrogen or lower alkyl,
R
7
represents hydrogen or sulfo,
D represents —N═N— when B is —N═N— and represents —NHCO—, —N═N— or —NH— when B is —NHCO—,
and E represents a phenyl optionally having 1 to 3 groups selected from hydroxyl amino, nitro, sulfo, carboxyl, lower alkyl and lower alkoxy.
The present invention further provides a dye-based polarization film obtainable by adding the above-mentioned polyazo compound or salt thereof into a polarization film substrate.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
A in the above-mentioned formula (I) represents a naphthyl having 1 to 3 sulfos or a phenyl having 1 to 2 hydrophilic groups selected from sulfo and carboxyl and optionally having a lower alkyl or lower alkoxy. The lower alkyl or lower alkoxy is preferably a linear or branched group having 1 to 4 carbon atoms. Specific examples of the lower alkyl include methyl, ethyl, propyl and the like. Specific examples of the lower alkoxy include methoxy, ethoxy, propoxy and the like.
Examples of the phenyl represented by A include 2-, 3- or 4-sulfophenyl, 2-, 3- or 4-carboxyphenyl, 2,4- or 2,5-disulfophenyl, 3,5-dicarboxyphenyl, 2-carboxy-4- or -5-sulfophenyl, 2 - or 3-methyl-4-sulfophenyl, and the like. Among them, 4-sulfophenyl is preferable.
Examples of the naphthyl represented by A include 5-, 6-, 7- or 8-sulfo-2-naphthyl, 4-, 5-, 6- or 7-sulfo-1-naphthyl, 1,5-, 6,8-, 4,8-, 5,7- or 3,6-disulfo-2-naphthyl, 3,6- or 4,6-disulfo-1-naphthyl, and 1,5,7-, 3,6,8- or 4,6,8-trisulfo-2-naphthyl and the like. Among them, naphthyls having 2 to 3 sulfos are preferable, and disulfo-2-naphthyls such as 1,5-, 6,8-, 4,8-, 5,7- or 3,6-disulfo-2-naphthyl and the like are particularly preferable.
R
1
to R
6
, which are the same as or different from each other, represent hydrogen, lower alkyl or lower alkoxy, provided that, when n represents , R
1
to R
4
represent hydrogen or lower alkyl, and do not represent a lower alkoxy. As the lower alkyl and lower alkoxy, linear or branched groups having 1 to 4 carbon atoms are preferable. As specific examples of the lower alkyl, methyl, ethyl. propyl and the like are listed. As specific examples of the lower alkoxy, methoxy, ethoxy, propoxy and the like are listed.
R
1
to R
6
preferably represent hydrogen or methyl.
R
7
represents hydrogen or sulfo, and preferably hydrogen.
E represents a phenyl optionally having 1 to 3 groups selected from hydroxyl, amino, nitro, sulfo, carboxyl, lower alkyl and lower alkoxy. Examples of the lower alkyl and lower alkoxy include those exemplified as the substituent of the phenyl represented by A. E preferably represents 4-hydroxyphenyl or 4-aminophenyl.
A polyazo compound of the formula (I) wherein n represents 0 and B represents —NHCO— or a salt thereof can be produced, for example, by methods described below.
First, an amide compound of the following formula (II):
wherein, A, R
1
and R
2
are as defined above, is diazotized by reacting with sodium nitrite in an acidic aqueous medium under a condition of 5 to 40° C. The resulted diazotized compound is reacted with an aniline compound of the following formula (III):
wherein, R
3
and R
4
are as defined above, in an aqueous medium under conditions of 5 to 40° C. and pH from 6 to 11, to obtain a monoazo compound. The resulted monoazo compound is diazotized by reacting with sodium nitrite in an acidic aqueous medium under a condition of 5 to 40° C. The resulted second diazotized compound is reacted with a hydroxynaphthalene compound of the following formula (IV):
wherein, R
7
D and E are as defined above, in an aqueous medium under conditions of 5 to 40° C. and pH from 6 to 11, to obtain an azo compound of the formula (I).
Examples of an azo compound of the formula (I) wherein n represents 0 and B represents —NHCO— include
and the like.
A polyazo compound of the formula (I) wherein n represents 0 and B represents —N═N— or a salt thereof can be produced, for exampler by a method described below.
First, a disazo compound of the following formula (V):
wherein, A, R
1
, R
2
, R
3
and R
4
are as defined above, is diazotized by reacting with sodium nitrite in an acidic aqueous medium under a condition of 5 to 40° C. The resulted diazotized compound is reacted with a naphthol compound of the formula (TV) wherein D represents —N═N— in an aqueous medium under conditions of 5 to 40° C. and pH from 6 to 11, to obtain a polyazo compound of the formula (I) or salt thereof.
Examples of a polyazo compound of the formula (I) wherein n represents 0 and B represents —N═N— include
and the like.
A polyazo compound of the formula (I) wherein n represents 1 and B represents —NHCO— or a salt thereof can be produced, for example, by a method described below.
First, a disazo compound of the following formula (VI):
wherein, A and R
1
to R
6
are as defined above, is diazotized with sodium nitrite in an acidic aqueous medium under a condition of 5 to 40° C. Then, the resulted diazotized compound is reacted with a naphthol compound of the above-described formula (IV) in an aqueous medium under conditions of 5 to 40° C. and pH from 6 to 11, to obtain a polyazo compound of the formula (I) or a salt thereof.
As the compound of the formula (IV), compounds of the following formula (VII) or (VIII)
wherein, R
7
has the above-mentioned meaning, and R
8
represents hydrogen, amino or hydroxyl, are preferable.
Specific examples of a compoun

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