JP2002193995A - Dicholesteryl ester and recording display material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel dicholesteryl ester which has high color stability with the passage of time and which achieves recording or full color recording by a specified rewritable color, and also provide a recording display material using the same. SOLUTION: The dicholesteryl ester is represented by the general formula: YO-CO(CH2)n-R-(CH2)mCO-OY [wherein, Y represents a cholesterol residue which is obtained by removing a hydroxyl group from a cholesterol with which the hydroxyl group combines; R represents one of groups represented by formulas (1) to (6); n and m represent each the same or different integer of 1-20; l in formula (1) represents an integer of 2-20].

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cholesteryl ester which is a liquid crystal compound and a rewritable thermosensitive recording or display material of a specific color or full color.

[0002]

2. Description of the Related Art A color photograph and a color copy are known as recording materials capable of recording full color and not rewriting. Non-full-color rewritable recording materials include thermosensitive recording materials containing long-chain alkyl carboxylic acid derivatives such as behenic acid, optical recording materials using photochromic compounds such as spiropyran derivatives, and other memories such as magnetism and magneto-optics. Materials are known.

Conventional recording materials have not achieved both full color and rewritable characteristics. Certainly, some display materials change their display, such as televisions and liquid crystal displays, and there are full-color ones, but they can be used as a thin card that fits in a wallet or display images stably forever without a power supply It could not be used as a substitute for recording material.

In recent years, full-color recording which can be rewritten by a new method using a liquid crystal compound has been achieved (Japanese Patent Laid-Open No. Hei 1 (1994)).
No. 1-24027, Patent No. 2936137,
Japanese Patent No. 2946042, JP-A-2000-7613
No.).

According to the above publication, it is possible to fix the interference color of the cholesteric phase represented by the liquid crystal substance by rapidly cooling it to around 0 ° C. There has been a demand for a new liquid crystal material capable of stably fixing various colors in order to provide a variety of temperature ranges and wavelength ranges in which colors can be fixed.

[0006]

DISCLOSURE OF THE INVENTION In view of the above-mentioned conventional problems, the present invention provides a novel cholesteryl ester which has high color stability over time and achieves recording in a rewritable specific color or full-color recording, and a record display. The purpose is to provide the material.

[0007]

SUMMARY OF THE INVENTION Namely, the present invention is di-cholesteryl ester YO-CO of the following formula _{(I) (CH 2) n} -R- (CH 2) m CO-OY ...... ( I) (wherein, Y represents a cholesterol residue obtained by removing a hydroxyl group bonded thereto from cholesterol, R is any group shown in the following (1) to (6), and n and m are
The same or different, and each represents an integer of 1 to 20.
In the following (1), 1 represents an integer of 2 to 20. )

[0008]

Embedded image And a recording and display material comprising the dicholesteryl ester.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The cholesteryl ester of the present invention is represented by the following general formula (I). YO-CO (CH ₂ ) _n -R- (CH ₂ ) _m CO-OY (I) (wherein, Y represents a cholesterol residue obtained by removing a hydroxyl group bonded thereto from cholesterol; (1) to any one of the groups shown in (6), wherein n and m are
Each represents the same or different, preferably the same, and represents an integer of 1 to 20, preferably an integer of 3 to 11. In the above (1), 1 is 2 to 20, preferably 2
Represents an integer of 1 to 11. )

The cholesteryl ester of the present invention is synthesized, for example, by the following method.

[0011]

Embedded image

[0012]

Embedded image

[0013]

Embedded image

Further, it is also synthesized by subjecting a long-chain dibasic acid represented by the following formula (II) to a condensation reaction with cholesterol. HOOC- (CH ₂ ) _n -R- (CH ₂ ) _m -COOH (II) (wherein, Y represents a cholesterol residue obtained by removing a hydroxyl group bonded thereto from R, and R represents the above-mentioned (1) ) To (6), wherein n and m are
Each represents the same or different, preferably the same, and represents an integer of 1 to 20, preferably an integer of 3 to 11. In the above (1), 1 is 2 to 20, preferably 2
Represents an integer of 1 to 11. )

The cholesteryl ester of the present invention is a liquid crystal compound and can reproduce a specific color or a color in the entire visible region (full color) depending on the heating temperature. Further, the color (reflected light) can be fixed, and it can be used as a thermosensitive recording material capable of being fixed to a full color or a specific color.

The recording and display material of the present invention comprises the above-mentioned cholesteryl ester, and is used in the form of a dicholesteryl ester of the present invention alone or in a mixture. When used as a mixture, examples of the compound to be mixed include a liquid crystal compound such as another cholesteryl ester and cholesterol. Further, additives such as a dye and an antioxidant can be included. In this case, the amount of the dicholesteryl ester of the present invention is preferably 90% by weight or more.

As an embodiment of the recording / display material of the present invention, for example, a recording / display material comprising at least one of the above-mentioned cholesteryl esters sandwiched between two substrates having a transparent portion is mentioned.

The substrate used in the present invention is usually a thin glass plate or the like, but may be a metal plate or a thin film such as a polymer film. In addition, one of the two sheets needs to have transparency so that at least a part of light is transmitted. When light is used for writing or erasing a record as described later, it is desirable that one substrate absorbs the light.

As a method of sandwiching the cholesteryl ester of the present invention between two substrates, first, the cholesteryl ester of the present invention or a mixture containing the cholesteryl ester is heated to a temperature of a molten state or a liquid crystal state, And the other substrate is placed on top of it, or inserted between two substrates kept in parallel by utilizing reduced pressure or capillary phenomenon.

The distance between the substrates is not particularly limited, but is preferably about several μm to 100 μm.

The recording and display material of the present invention can perform recording (writing) and display of recording by partial or total heating. For the heating, a thermal head,
All methods such as a heating roll and a laser beam are possible. Heating that requires temperature control to the liquid crystal temperature range can be achieved by controlling the temperature of the thermal head or heating roll, adjusting the intensity or spot diameter of the laser beam, or by heating the entire unit to a certain temperature. This can be achieved by lowering the temperature to the required temperature with a flat metal plate or rubber plate.

On the other hand, in order to fix the color of the cholesteryl ester of the present invention, it is necessary to rapidly cool the cholesteryl ester to a temperature lower than its glass transition temperature. Or a method of immersing in a cooled atmosphere, or a method of contacting a part with a cooled head.

Another embodiment of the recording and display material of the present invention is a dispersion in which the cholesteryl ester of the present invention or a mixture containing the same is dispersed in a polymer compound film or another molded product.

The recording and display material of the present invention includes, for example, cards, sheets for overhead projects, labels,
It can be used as a ticket or the like, and if necessary, a protective layer, a back surface layer, and the like may be further provided. For example, in the case of a label, a mount is provided on the back surface of the recording display material via an adhesive layer. In the case of a magnetic ticket, a magnetic recording layer made of a binder and a ferromagnetic powder is provided in place of the mount.

[0025]

EXAMPLES (Example 1) According to the above reaction formula (a), R =
(1) A cholesteryl ester in which n = m = 9 and l = 4 was synthesized.

2.2 g of 1,9-nonanedicarboxylic acid (1
0 mmol), 3.7 g of cholesterol (10 mmol)
l) and 2.2 g of dicyclohexylcarbimide (10
mmol) was dissolved in 80 ml of methylene chloride, and 0.18 g (1.0 ml) of 4-dimethylaminopyridine was used as a condensation catalyst.
mmol) at room temperature for 24 hours. Separation and purification by column chromatography gave 2.3 g of cholesteryl ester.

0.41 g of this cholesteryl ester
(0.7 mmol), 1,4-butanediol 0.03
g (0.35 mmol) and 0.21 g (1.0 mmol) of dicyclohexylcarbimide in 5 m of methylene chloride.
and stirred at room temperature for 24 hours with 0.01 g (0.07 mmol) of 4-dimethylaminopyridine as a condensation catalyst. Separation and purification by column chromatography gave 0.15 g of cholesteryl ester.

The cholesteryl ester was added to a thickness of 0.1
It was sandwiched between two 8 mm glass plates, and the whole was heated to 100 ° C. and melted to prepare a sample portion having a thickness of 20 μm.

Next, when the sample was placed on a hot stage maintained at 94 ° C., the whole was blue. Then, when the sample was quickly immersed in ice water, the sample solidified and the blue state was fixed as it was. When the reflection spectrum was measured, it was found that the light was reflected in a wavelength region having a maximum at 410 nm.

Example 2 According to the above reaction formula (b), R
= (2), n = m = 6, dicholesteryl ester was synthesized.

5.2 g (30 mmol) of suberic acid,
11.6 g (30 mmol) of cholesterol and 6.2 g (30 mmol) of dicyclohexylcarbimide were dissolved in 240 ml of methylene chloride, and stirred at room temperature for 24 hours together with 0.37 g (3.0 mmol) of 4-dimethylaminopyridine as a condensation catalyst. Separation and purification by column chromatography gave 8.5 g of cholesteryl ester.

1.1 g of this cholesteryl ester (2.
0 mmol), 0.09 g of hydroquinone (0.80 mm
ol) and 0.41 g of dicyclohexylcarbimide
(2.0 mmol) was dissolved in 10 ml of methylene chloride,
4-dimethylaminopyridine 0.024 as a condensation catalyst
The mixture was stirred with g (0.20 mmol) at room temperature for 24 hours. Separation and purification by column chromatography gave cholesteryl ester 0.65 g.

Using this cholesteryl ester, 1
When the color was fixed in the same manner as in Example 1 except that the sample was prepared by heating to 90 ° C., the color was reflected at 180 ° C. to 140 ° C., and blue to green by rapid cooling (peak wavelength 443 nm to 545 nm). Could be fixed.

Example 3 According to the above reaction formula (b), R
= (4), n = m = 6, dicholesteryl ester was synthesized.

5.2 g (30 mmol) of suberic acid,
11.6 g (30 mmol) of cholesterol and 6.2 g (30 mmol) of dicyclohexylcarbimide were dissolved in 240 ml of methylene chloride, and stirred at room temperature for 24 hours together with 0.37 g (3.0 mmol) of 4-dimethylaminopyridine as a condensation catalyst. Separation and purification by column chromatography gave 8.5 g of cholesteryl ester.

1.1 g of this cholesteryl ester (2.
0 mmol), catechol 0.11 g (1.0 mmol)
l) and 0.41 g of dicyclohexylcarbimide
(2.0 mmol) was dissolved in 10 ml of methylene chloride,
0.024 as 4-dimethylaminopyridine as a condensation catalyst
The mixture was stirred with g (0.20 mmol) at room temperature for 24 hours. Separation and purification by column chromatography gave 0.7 g of cholesteryl ester.

Using this cholesteryl ester, 1
When the color was fixed in the same manner as in Example 1 except that the sample was prepared by heating to 30 ° C., a reflective color was exhibited at 120 ° C. to 93 ° C., and blue (peak wavelength 360 n
m-482 nm).

Example 4 According to the above reaction formula (c), R
= (5), dicholesteryl ester where n = m = 5 was synthesized.

10.5 g of 6-bromo-n-caproic acid
(52 mmol), 19.2 g of cholesterol (52 m
mol) and 10.8 g of dicyclohexylcarbimide
(52 mmol) in 280 ml of methylene chloride,
0.30 g of 4-dimethylaminopyridine as a condensation catalyst
(2.8 mmol) at room temperature for 15 hours. Recrystallization from ethanol gave 18 g of cholesteryl ester.

0.55 g of this cholesteryl ester
(1.0 mmol), 0.04 g of piperazine (0.5 m
mol) and potassium carbonate 0.28 g (2.0 mmol)
l) is mixed with 10 ml of 2-butanone,
Stirred for 0 hours. The obtained crude product was purified by a column of silica gel (developing solvent was methylene chloride) to obtain 0.15 g (0.14 mmol) of cholesteryl ester.

Using this cholesteryl ester, 1
The color was fixed in the same manner as in Example 1 except that the sample was prepared by heating to 40 ° C. When the color was fixed at 133 ° C. to 125 ° C., the color was reflected.
４413 nm).

Example 5 According to the above reaction formula (b), R
= (6), n = m = 8, dicholesteryl ester was synthesized.

8.1 g (40 mmol) of sebacic acid,
11.6 g (30 mmol) of cholesterol and 8.2 g (40 mmol) of dicyclohexylcarbimide were dissolved in 320 ml of methylene chloride, and the mixture was stirred at room temperature for 24 hours with 0.49 g (4.0 mmol) of 4-dimethylaminopyridine as a condensation catalyst. Separation and purification by column chromatography gave 7.0 g of cholesteryl ester.

1.1 g of this cholesteryl ester (2.
0 mmol), 0.18 g of biphenol (1.0 mmol
l) and 0.41 g of dicyclohexylcarbimide
(2.0 mmol) was dissolved in 10 ml of methylene chloride,
4-dimethylaminopyridine 0.024 as a condensation catalyst
The mixture was stirred with g (0.20 mmol) at room temperature for 24 hours. Separation and purification by column chromatography gave 0.15 g of cholesteryl ester.

Using this dicholesteryl ester, 2
When the color was fixed in the same manner as in Example 1 except that the sample was prepared by heating to 10 ° C., the color was reflected at 200 ° C. to 180 ° C., and rapidly cooled to green to red (peak wavelength 567 nm to 696 nm). Could be fixed.

[0046]

As described above, according to the present invention, recording with a rewritable specific color or full-color recording can be achieved, and color stability over time is excellent. Further, by using the dicholesteryl ester of the present invention, it is possible to widen the selection range of materials that can be used for recording and display, and it is possible to provide a variety of temperature ranges and wavelength ranges in which colors can be fixed.

Therefore, a full-color photograph can be recorded on a card or the like and can be freely rewritten. When used as a sheet for an overhead project,
It is possible to rewrite the color multiple times and use it, which is also effective for solving environmental problems.

Continuation of the front page (71) Applicant 597072464 Hiroo Matsuda 1966-8 Uenomuro, Tsukuba City, Ibaraki Prefecture (74) The above three agents 100096828 Attorney Keisuke Watanabe (two other) (72) Inventor Atsushi Takahashi Bunkyo-ku, Tokyo Koishikawa 4-chome No. 14-12 Kyodo Printing Co., Ltd. Address F-term in the National Institute of Advanced Industrial Science and Technology (Materials Engineering and Industrial Technology Research Institute)

Claims (4)

[Claims] 1. A cholesteryl ester represented by the following general formula (I). YO—CO (CH ₂ ) _n —R— (CH ₂ ) _m CO—OY (I) (wherein, Y represents a cholesterol residue obtained by removing a hydroxyl group bonded thereto from cholesterol, and R represents the following: (1) to any one of the groups shown in (6), wherein n and m are
The same or different, and each represents an integer of 1 to 20.
In the following (1), 1 represents an integer of 2 to 20. ) 2. A recording and display material comprising the dicholesteryl ester according to claim 1. 3. The recording and display material according to claim 2, wherein at least the cholesteryl ester is sandwiched between two substrates or thin films at least one of which has a transparent portion. 4. The recording and display material according to claim 2, wherein at least the cholesteryl ester is dispersed in a molded article having a transparent portion.