JP3229423B2 - Siloxane copolymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to a novel siloxane copolymer. More specifically, the present invention relates to the field of optoelectronics, in particular, digital display elements such as calculators and watches, dot matrix type display elements, room temperature switching elements, electro-optical shutters, electro-optical diaphragms, optical modulators, optical communication optical path switching switches, The present invention relates to a novel siloxane copolymer suitably used as a material of a liquid crystal element used for a memory, a liquid crystal printer head, a variable focal length lens, and the like.

[0002]

2. Description of the Related Art Conventionally, display devices using low-molecular liquid crystal compounds have been widely used for digital displays such as calculators and watches. In these fields of application, conventional low-molecular liquid crystal compounds are usually used between two glass substrates whose spacing is controlled on the order of microns. However,
Such adjustment of the interval cannot be realized on a large screen or a curved screen.

As a means for solving this difficulty, attempts have been made to polymerize the liquid crystal so that the liquid crystal itself can be molded [J. Polym. Sci. , Polym. L
ett. , Ed. 13 , 243 (1975), Poly
m. Bull. 6 , 309 (1982);
No. 21479, etc.]. However, these conventional polymer liquid crystal compounds have the disadvantage that the polymer itself does not exhibit the properties of a liquid crystal at room temperature, and must be converted into a liquid crystal by heating in a temperature range above the glass transition temperature and below the clearing temperature. are doing.

Japanese Patent Application Laid-Open No. 63-99204 reports the synthesis of a polyacrylate-based ferroelectric polymer liquid crystal compound. Has also been shown to exhibit excellent performance. However, even in this conventional side chain type ferroelectric polymer liquid crystal compound, the response speed,
Problems remain in the usable temperature range.

Further, JP-A-63-254529 discloses a polyether-based ferroelectric polymer liquid crystal compound obtained by polymerizing an epoxy monomer having an optically active group [for example, represented by the general formula (1): A repeating unit obtained by polymerizing an epoxy compound and represented by the general formula (1 '): u in the formulas (1) and (1') represents an integer of 1 to 30. And a liquid crystal compound of the formula [1].

[0006]

Embedded image In addition, WO 92/01731 pamphlet discloses that, for example, a compound represented by the following formula (2) comprising a repeating unit having an aromatic ring in a side chain and having a chain hydrocarbon skeleton and a siloxane skeleton in a main chain. A molecular liquid crystal compound is disclosed.

[0007]

Embedded image However, although these conventional side-chain ferroelectric polymer liquid crystal compounds have the advantage of responding to an external electric field stimulus in a wide temperature range including around room temperature, their response speed is slow, and they are not suitable for displaying moving images. It is still insufficient for practical use.

On the other hand, a polymer liquid crystal composition comprising a polymer liquid crystal compound having an asymmetric carbon and a low-molecular liquid crystal compound has been proposed as a liquid crystal composition (JP-A-63-284291).
No.). However, the side-chain type high-molecular liquid crystal compound exemplified has an ordinary acrylate or siloxane chain as the main chain, so the side-chain spacing is not sufficient, and when the molecular weight is increased, the low-molecular-weight liquid crystal compound can be sufficiently mixed. And speeding up becomes difficult. Therefore, while maintaining the conventional polymer properties,
There is a problem that it is difficult to obtain a composition having high-speed response.

An attempt to obtain a high-speed responsive composition while maintaining high polymerity with a composition comprising a non-liquid crystalline polymer compound and a low-molecular liquid crystal compound has been disclosed in Japanese Patent Application Laid-Open No.
No. 47427 discloses a composition in which a non-liquid crystalline polymer is blended with a low-molecular liquid crystal compound to impart a self-shape retention ability. In this composition, the liquid crystal region is dispersed in the polymer compound (resin) matrix, so that the liquid crystal region may be separated when left for a long period of time. However, since it is a dispersion system, it is difficult to control the orientation. JP-A-62-260859, JP-A-62-260841
Japanese Patent Application Laid-Open Publication No. H11-176,086 describes a ferroelectric composite film containing a thermoplastic resin and a low-molecular liquid crystal compound, in which a thermoplastic resin that becomes compatible is used, but a low-molecular compound that becomes compatible with this thermoplastic resin is used. It is difficult to combine liquid crystal compounds and control alignment. In addition, there is a problem that low-molecular liquid crystal compounds to be used are limited to ferroelectric liquid crystals. JP-A-1-19868
No. 3 discloses a polymer having a proton donor (or proton acceptor) and a proton acceptor (or proton donor).
Although a composition comprising a low-molecular liquid crystal compound having the following formula is described, both the polymer and the low-molecular liquid crystal compound must have a proton donor (or a proton acceptor).
The problem is that both structures are quite limited.

Therefore, in preparing a composition comprising a low-molecular liquid crystal compound and a high-molecular compound, a high-molecular compound which is compatible with various low-molecular liquid-crystal compounds and does not undergo phase separation is required.

[0011]

SUMMARY OF THE INVENTION The present invention provides a ferroelectric liquid crystal composition having good alignment properties (the alignment can be easily performed), good contrast ratio, and high-speed response to an electric field change near room temperature. It is an object of the present invention to provide a siloxane copolymer which can be suitably used as a polymer material of a product.

[0012]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, it has been found that a copolymer composed of a specific methyl-substituted siloxane having a side chain and dimethylsiloxane is a low-molecular liquid crystal. They have found that they have excellent compatibility with compounds and that the liquid crystal compositions have excellent properties as polymer materials, and have completed the present invention based on these findings.

That is, the present invention provides a siloxane copolymer represented by the following general formula [I].

[0014]

Embedded image (Where X is

[0015]

Embedded image Y represents a single bond or -COO-, and m represents 6
An integer of ２０20, n represents a number of 1８8, * represents an asymmetric carbon atom, and x is a number representing a copolymerization ratio of 0.1〜0.7. The siloxane copolymer of the present invention has a dimethylsiloxane copolymer part in the main chain and has a part with a wide side chain interval, so that it is easily mixed even when mixed with a low-molecular liquid crystal compound,
The mixture becomes compatible and no phase separation occurs. Therefore,
It is suitable as a polymer material for a ferroelectric liquid crystal composition.

Further, the composition using the siloxane copolymer of the present invention has a large spontaneous polarization because it has a 1-methylalkoxycarbonyl group or a lactate group as an optically active group. Therefore, it responds quickly to the electric field.

Further, by merely changing the copolymerization ratio of the methylhydrogen-dimethylsiloxane copolymer used in the synthesis of the siloxane copolymer, the transition temperature of the copolymer,
The transition temperature of the ferroelectric liquid crystal composition containing the copolymer can be easily controlled.

The siloxane copolymer of the present invention does not necessarily have to exhibit a liquid crystal phase. In preparing the ferroelectric liquid crystal composition, the compound may function as a chiral dopant and play a role in imparting moldability and orientation to the composition. The ferroelectricity of the liquid crystal composition can be easily developed by appropriately selecting other components to be blended.

The weight average molecular weight (Mw) of the siloxane copolymer of the present invention is usually from 1,000 to 1,000,000.
0, preferably 1,000 to 100,000. When the Mw is less than 1,000, the moldability as a film or a coating film of the composition containing the siloxane copolymer may be hindered, while when it exceeds 1,000,000, the response time is long. Undesirable effects may appear.

The siloxane copolymer of the present invention has a copolymerization ratio x
Of 0.1 to 0.7 is used. When x is less than 0.1 or exceeds 0.7, the compatibility with the low-molecular liquid crystal compound is reduced. The preferable range of x is 0.3 to 0.6.

The method for producing the siloxane copolymer of the present invention is not particularly limited and may be produced by any method. For example, the following general formula [I]
I] and a side chain component having a double bond at a terminal represented by the following general formula [III] (compound II):
I) can be suitably produced by performing a hydrosilylation reaction in a solvent in the presence of a catalyst in a proportion in which hydrosilane and double bonds are almost equimolar. The reaction proceeds, for example, as follows.

[0022]

Embedded image (Wherein, X, Y, m, n, *, x represent the same meaning as described above)

Examples of the solvent used in the synthesis reaction of the compound I include inert aromatic hydrocarbons such as benzene, toluene and xylene, tetrahydrofuran (THF),
Inert ether solvents such as diisopropyl ether are preferably used. The solvent may be a single solvent or a mixed solvent, but usually has a boiling point of 70 from the relation of the reaction temperature.
C. or higher is preferably used. Further, as the catalyst, those having hydrosilylation activity are used,
Specifically, for example, platinum-based catalysts such as chloroplatinic acid, platinum (II) acetylacetonate, and dicyclopentadienyl platinum platinum chloride are preferably used.

The order and manner of addition of each component in the synthesis reaction are not particularly limited. For example, a mixture of a methylhydrogen-dimethylsiloxane copolymer and a side chain component in a predetermined ratio may be Preferred examples include a method in which a solvent such as toluene and THF is added, and then a suitable amount of a catalyst such as chloroplatinic acid is added.
The catalyst may be added alone or may be dissolved in a solvent such as isopropyl alcohol.

The above synthesis reaction can be suitably carried out in an inert atmosphere such as nitrogen gas or argon at a temperature of usually 60 to 100 ° C., preferably 80 to 100 ° C. The reaction time is usually about 3 to 30 hours.

The desired siloxane copolymer can be synthesized as described above. The siloxane copolymer thus obtained is separated and recovered from the reaction mixture by a known method or the like, and can be obtained as a siloxane copolymer having a desired degree of purification. The highly purified siloxane copolymer of the present invention is obtained, for example, by filtering the reaction mixture after the completion of the synthesis reaction and distilling the solvent from the filtrate to obtain a residue, which is dissolved in a suitable solvent such as methylene chloride. And purified by column chromatography using, for example, silica gel or the like as a filler.

Compounds II and III, which are starting compounds suitably used for producing the polymer compound of the present invention.
Can be synthesized by a known method, and a method for synthesizing compound III is described in JP-A-2-640.

[0028]

Next, the present invention will be described based on examples, but the present invention is not limited to these examples.

In the formula showing the phase transition behavior, each symbol has the following meaning. glass: glass phase, S _C ^* : chiral smectic C
Phase, S _X ^* : smectic phase higher than S _C ^* phase, Iso:
Isotropic liquid phase, S _A : Smectic A phase, N ^* : Chiral nematic phase, Cryst: Crystal state The phase transition temperature was determined by observation with a polarizing microscope. In the equation showing the phase transition behavior, the numbers represent ° C.

Example 1 Synthesis of Copolymer 1

[0031]

Embedded image1.5 g of the polymerization precursor (A) and methyl hydrogeno (27
%)-Dimethyl (73%) siloxane copolymer 0.17
g to H_TwoPtCl₆Triggered in the presence of a catalyst under a stream of argon
After stirring at 90 ° C for 20 hours with a 10 ml solution of
Purified by Kagel column chromatography, copolymer
0.27 g (18% yield) of 1 was obtained. Of the resulting compound
¹H -NMR (TMS / CDCl_Three) The chart is shown in Fig. 1.
You.

Example 2 Synthesis of copolymer 2

[0033]

Embedded image1.5 g of the polymerization precursor (B) and methyl hydrogeno (27
%)-Dimethyl (73%) siloxane copolymer 0.20
g to H_TwoPtCl₆In the presence of a catalyst, the same reaction as in Example 1 was performed.
The reaction is carried out under the appropriate conditions, and silica gel column chromatography
The copolymer 2 was purified by 0.20 g (yield 13
%)Obtained. Of the resulting compound¹H -NMR (TMS / C
DCI_Three) Data (ppm) are shown. 0.07 (20.2H, m), 0.50 (2H, m),
0.94 (3H, bt), 1.32 (3H, bd),
1.35-1.75 (20H, m), 4.00 (2H,
m), 5.16 (1H, m), 6.93 (2H, m),
7.25 (2H, m), 8.08 (4H, m)

Example 3 Synthesis of Copolymer 3

[0035]

Embedded image1.3 g of the polymerization precursor (C) and methyl hydrogeno (70
%)-Dimethyl (30%) siloxane copolymer 0.19
g to H_TwoPtCl₆In the presence of a catalyst, the same reaction as in Example 1 was performed.
The reaction is carried out under the appropriate conditions, and silica gel column chromatography
The copolymer 3 was purified by 0.24 g (yield 18).
%)Obtained. Of the resulting compound¹H -NMR (TMS / C
DCI_Three) Data (ppm) are shown. 0.10 (11.3H, m), 0.52 (2H, m),
0.96 (3H, bt), 1.31 (3H, bd),
1.36-1.78 (16H, m), 4.01 (2H,
m), 5.18 (1H, m), 7.01 (2H, m),
7.62 (4H, m), 8.08 (2H, m)

Example 4 Synthesis of Copolymer 4

[0037]

Embedded image1.5 g of the polymerization precursor (D) and methyl hydrogeno (30
%)-Dimethyl (70%) siloxane copolymer 0.17
g to H_TwoPtCl₈In the presence of a catalyst, the same reaction as in Example 1 was performed.
The reaction is carried out under the appropriate conditions, and silica gel column chromatography
The copolymer 4 was purified by 0.25 g (yield 17
%)Obtained. Of the resulting compound¹H -NMR (TMS / C
DCI_Three) Data (ppm) are shown. 0.08 (18.
1H, m), 0.50 (2H, m), 0.90 (3H,
m), 1.35 (3H, bd), 1.34-1.76
(30H, m), 4.00 (2H, m), 5.17 (1
H, m), 6.93 (2H, m), 7.25 (2H,
m), 8.09 (4H, m)

Example 5 Synthesis of Copolymer 5

[0039]

Embedded image1.2 g of the polymerization precursor (E) and methyl hydrogeno (40
%)-Dimethyl (60%) siloxane copolymer 0.20
g to H_TwoPtCl₆In the presence of a catalyst, the same reaction as in Example 1 was performed.
The reaction is carried out under the appropriate conditions, and silica gel column chromatography
The copolymer 5 was purified by 0.19 g (yield 15
%)Obtained. Of the resulting compound¹H -NMR (TMS / C
DCI_Three) Data (ppm) are shown. 0.07 (13H, m), 0.50 (2H, m), 0.
86 (3H, bt), 1.33 (3H, m), 1.35
-1.75 (12H, m), 4.00 (2H, m),
5.14 (1H, m), 6.98 (2H, d), 8.4
4 (2H, d), 9.25 (2H, s)

Example 6 Synthesis of Copolymer 6

[0041]

Embedded image1.5 g of the polymerization precursor (F) and methyl hydrogeno (60
%)-Dimethyl (40%) siloxane copolymer 0.16
g to H_TwoPtCl₆In the presence of a catalyst, the same reaction as in Example 1 was performed.
The reaction is carried out under the appropriate conditions, and silica gel column chromatography
The copolymer 6 was purified by 0.25 g (yield 17
%)Obtained. Of the resulting compound¹H -NMR (TMS / C
DCI_Three) Data (ppm) are shown. 0.07 (7.8H, m), 0.51 (2H, m),
1.21 (3H, t), 1.35-1.65 (12H,
m), 1.65 (3H, d), 4.00 (2H, m),
4.13 (2H, q), 5.30 (1H, q), 6.9
5-8.10 (12H, m)

Example 7 Synthesis of Copolymer 7

[0043]

Embedded image1.5 g of the polymerization precursor (G) and methyl hydrogeno (30
%)-Dimethyl (70%) siloxane copolymer 0.17
g to H_TwoPtCl₈In the presence of a catalyst, the same reaction as in Example 1 was performed.
The reaction is carried out under the appropriate conditions, and silica gel column chromatography
And purified by 0.30 g of copolymer 7 (yield: 20).
%)Obtained. Of the resulting compound¹H -NMR (TMS / C
DCI_Three) Data (ppm) are shown. 0.07 (17.6H, m), 0.51 (2H, m),
0.86 (3H, m), 1.31 (3H, bd), 1.
33-1.72 (18H, m), 4.01 (2H,
m), 5.15 (1H, m), 7.01 (2H, d),
7.22 (2H, d), 8.12 (2H, d), 8.4
5 (2H, d), 9.27 (2H, s)

Table 1 shows the copolymers 1 obtained in Examples 1 to 7.
7 shows the weight average molecular weight, phase transition behavior, and response time to electric field change of Nos. 7 to 7. The response time was measured using an electrode area of 0.2 c.
sandwiching the copolymer between ITO substrates m ^2, to adjust the thickness to 2μm by a spacer, the measurement of applying a rectangular wave of ± 10V / [mu] m, the amount of transmitted light change when the (10 → 90%) It was done by doing.

[0045]

[Table 1]

Example 8 A copolymer was obtained by mixing the copolymer 3 obtained in Example 3 with the following low-molecular smectic liquid crystal compound a in the ratio shown in Table 2. Low molecular smectic liquid crystal compound a

[0047]

Embedded image

Mixing method Each was weighed so as to have the ratio shown in Table 2, dissolved in 5 cc of a solvent (dichloromethane), mixed, and then mixed at about 100 ° C.
To evaporate the solvent.

When the above composition was sandwiched between glass substrates with ITO electrodes and observed under a polarizing microscope, no island-like structure peculiar to the dispersion system was observed, and the composition was uniformly in a liquid crystal phase.
It was confirmed that they were compatible. Microscopic observation,
The observation was carried out while changing the temperature between 100 ° C. and room temperature at a magnification of 400 ×.

[0050] over a period of several times the shear stress between the upper and lower substrates in the composition was sandwiched by a glass substrate with ITO electrodes (electrode area ^{0.5cm 2), 80 ℃ (S} A phase) (orientation by shearing method) The liquid crystal was aligned (the cell thickness was 2 μm). A voltage of ± 10 V / μm was applied thereto at 25 ° C., and the response time was measured.

From the above results, it can be seen that the present composition shows ferroelectricity and high-speed response.

[0052]

[Table 2] The cell used for measuring the response speed was ± 10 V / μm.
Was applied and the contrast ratio was measured.
And a good contrast was obtained.

[0053]

According to the present invention, a polymer material of a ferroelectric liquid crystal composition having good alignment properties (alignment can be easily performed), good contrast ratio, and high-speed response to an electric field near room temperature. The siloxane copolymer which can be used conveniently as was obtained.

[Brief description of the drawings]

FIG. 1 shows the siloxane copolymer obtained in Example 1.¹H -N
MR chart.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Satoshi Hachiya 1280 Kamiizumi, Sodegaura-shi, Chiba Idemitsu Kosan Co., Ltd. (56) References JP-A-6-207022 (JP, A) JP-A-4-31405 ( JP, A) (58) Fields surveyed (Int. Cl. ⁷ , DB name) C08G 77/38 C08G 77/04 C08L 83/04

Claims (1)

(57) [Claims] 1. A siloxane copolymer represented by the following general formula [I]. Embedded image (Wherein X is Y represents a single bond or -COO-, and m represents 6
N is an integer of 1 to 8, * is an asymmetric carbon atom, and x is a number indicating a copolymerization ratio of 0.1 to 0.7. )