JP2641274B2 - Liquid crystal-forming polymer and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention provides a novel liquid crystal-forming polymer exhibiting high-speed response, which is useful in fields such as display devices, optical recording media, and nonlinear optical devices. is there.

<Conventional technology> Conventionally, liquid crystal compounds are known as typical display materials,
It is used in fields such as watches, calculators, and small televisions. In recent years, with the progress of display functions, demands for solidification of element materials have been increasing, and from such a viewpoint, the demand for liquid crystal polymers in addition to conventional low molecular liquid crystals has also increased. In addition to liquid crystal polymers, application to optical recording materials is expected in addition to application to display elements.

However, the generally known liquid crystal polymer has a disadvantage that the response due to the electro-optic effect is low because it is a polymer. To avoid the drawbacks, ferroelectric chiral liquid crystals have been proposed that cause a liquid crystal phase transition even without a large displacement of the polymer chain, but have yet to reach a practical range where the required performance can be sufficiently satisfied. Not in.

On the other hand, liquid crystal polymers have the property of being oriented by an electric or magnetic field, and their dipoles can be aligned by utilizing the property, so that expectations as a nonlinear optical material are increasing. This material is used in the form of a thin film waveguide as a surface in the optical communication and optical IC fields. However, in general, it is difficult to form a fine circuit because a polymer exhibiting non-linear optical characteristics has no pattern-forming property.

<Means for Solving the Problem> The inventors of the present invention have conducted intensive studies to solve the above problems, and as a result, have found that a chiral alkyl ester structure of cinnamic acid exhibiting photosensitivity is converted into a mesogen of a (meth) acrylic acid polymer side chain. By introducing as a component, a polymer having a chiral group is obtained, and this polymer forms Sc ^* liquid crystal, and when this thin film is irradiated with actinic rays, the irradiated portion is cross-linked to form a waveguide. This has led to the present invention.

That is, the present invention relates to: 1. The following general formula: A monomer required for producing a liquid crystal-forming polymer represented by the formula: 2. The following general formula: A liquid crystal-forming polymer (II) comprising a repeating unit (A) represented by the following formula: 3. characterized in that the monomer represented by the general formula (I) is polymerized by heating in the presence of a radical polymerization initiator. A method for producing a liquid crystal-forming polymer (II); and 4. a pattern forming method, which comprises irradiating actinic rays to a film made of the polymer (II).

 Hereinafter, the present invention will be described in detail.

A polymer (II) having a monomer represented by the general formula (I) (hereinafter referred to as monomer (I)) and a repeating unit represented by (A) (hereinafter referred to as monomer (II)) In the formula, R ₁ is a hydrogen atom, a chlorine atom or a methyl group. R ₂ is a flexible (flexible) group that links the main chain and the regular mesogen group in the liquid crystal polymer, and has 2 carbon atoms.
-20, preferably 4-15 linear and branched alkylene groups. Its role is to block the mesogen group representing the liquid crystal from affecting the main chain.

n is 0 or 1, and X is a hydrogen atom, a chlorine atom, a methyl group or a cyano group. n and X affect the absorption spectrum, where n is 1 more than 0 and R is CN than H, monomer (I) and polymer (II) exhibit the longer maximum absorption wavelength; In addition, it is sensitive to longer wavelength light.

In the present invention, R ₁ , R ₂ , n and X used in the polymer may be one kind or two or more kinds. By appropriately combining these, the liquid crystallinity and the liquid crystal phase transition temperature can be controlled.

R ₃ ^* is an optically active monovalent linear or cyclic alkyl group having an asymmetric carbon atom having 4 to 15 carbon atoms. In general, even an alkyl group having an asymmetric carbon atom is optically inactive. In other words, a racemic form is not preferable because a chiral liquid crystal showing Sc ^* cannot be obtained. As specific examples, R- and S-2-butyl groups, R- and S-2
-Heptyl group, R- and S-3-methyl-2-butyl group, R- and S-2-octyl group, R- and S-1
-A pentyl group and a menthyl group.

In addition, as long as the characteristics of the present invention are not impaired, the formula (II)
In the polymer having the repeating unit represented by the formula (II),
And repeating units exhibiting liquid crystal properties other than the repeating units described above.

The method for producing these monomers (I) is not particularly limited,
As shown in the following formula, after the hydroxyl group of hydroxyalkyloxybenzoic acid is acylated with (meth) acrylic acid, it is activated by derivatization to an acid chloride, and then activated with p-hydroxycinnamic acid and p-hydroxycinnamate. A method of coupling mylideneacetic acid or a cyano derivative thereof and finally esterifying with an optically active alcohol is preferred.

Further, a method of coupling (meth) acryloyloxyalkyloxybenzoic acid chloride with an optically active alkyl ester of p-hydroxycinnamic acid, p-hydroxycinnamylideneacetic acid, or a cyano derivative thereof is also preferably used.

The polymer (II) can be produced by subjecting the monomer (I) to radical polymerization.

The radical polymerization initiator is not particularly limited, but peroxides such as di-tert-butyl peroxide and benzoyl peroxide, and azo compounds such as azobisisobutyronitrile are preferably used. The reaction is usually performed in an organic solvent. Preferred examples include organic solvents such as benzene, hexane, cyclohexane, ether, dioxane, methyl acetate, methyl ethyl ketone, chloroform, dimethylformamide, and dimethylacetamide. The polymerization temperature is generally 30 to 200 ° C, preferably 50 to 120 ° C.

The structural analysis of the monomer (I) and the polymer (II) obtained in the present invention can be performed by, for example, elemental analysis, infrared absorption spectrum, ultraviolet-visible absorption spectrum, near magnetic resonance absorption spectrum and the like.

The film made of the polymer (II) can form a pattern by irradiating it with actinic rays. In this case, the double bond in the repeating unit represented by the formula (A) undergoes a photochemical reaction to be crosslinked and cured. The coating method is not particularly limited, but is generally dissolved in an organic solvent and then applied to a doctor knife method, a bar coater method, a spin coater method,
A dry film is formed by a gravure coating method or the like. At that time, a stabilizer, a sensitizer and the like may be added. Active rays for forming a circuit include ultraviolet rays, visible rays,
An electron beam or the like is preferably used.

<Function> The liquid crystal-forming polymer thus obtained provides a material useful in the information recording field and the communication field as a display element, a recording medium, a nonlinear optical element, and the like.

<Example> Hereinafter, the present invention will be described with reference to examples. However, the present invention is not limited to this.

Example 1 Among the monomer (I) and the polymer (II), R ₁ = H and R ₂ =
_{- (CH 2) 11 -,} n = 0, X = CN and R ₃ ^* = -CH ₂ CH
(CH ₃ ) C ₂ H ₅ will be described.

27.6 parts of p-hydroxybenzoic acid (1) were added to an equimolar alcoholic potassium hydroxide solution containing a catalytic amount of potassium iodide. Then, ω-bromoundecanol 50.2
The mixture was heated at reflux for 5 hours. The reaction mixture was subjected to acid precipitation, and the obtained solid was separated by filtration and recrystallized from a mixed solvent of ethanol / water to obtain 52.4 parts of ω-hydroxyundecyloxybenzoic acid (2).

31.0 parts of the obtained compound (2) and 7.2 parts of acrylic acid were added to chloroform, 0.6 parts of p-toluenesulfonic acid was added as a catalyst, and the mixture was heated under reflux for 18 hours. Water by-produced during the reaction was distilled off azeotropically with benzene. After the reaction, the solvent was distilled off, and the obtained solid was washed with water to give compound (3).
30 copies were obtained.

18 parts of the compound (3) was added to 7.0 parts of thionyl chloride, and the mixture was heated under reflux for 1 hour. After completion of the reaction, the solvent and by-products were distilled off, and this was treated with α-cyano-p-hydroxycinnamic acid 9.0.
Was added under cooling to a solution of equimolar triethylamine in tetrahydrofuran. The reaction mixture was poured into water, and the deposited precipitate was separated by filtration, and recrystallized or separated by chromatography from tetrahydrofuran to obtain 20.0 parts of compound (4).

20.0 parts of compound (4) was added to a benzene solution containing 6.0 parts of thionyl chloride, and the mixture was heated under reflux for 5 hours. After evaporating the solvent, unreacted materials and by-products, the mixture was added to a pyridine solution containing 4.0 parts of (+)-2-methyl-1-butanol under cooling. The reaction mixture was poured into water, and the purified solid was recrystallized from tetrahydrofuran to obtain the desired monomer (I).
I got 15 parts.

The elemental analysis values of the monomer (I) were C71.15%, H7.90%, N2.
This was 21%, which was in good agreement with the theoretical values of C 71.62%, H 7.51%, and N 2.32%. Further, the infrared absorption spectrum characteristic absorption based on the stretching vibration of ester bond near 1710 cm ^-1 of this material, the cinnamic acid ester bond near 1610 cm ^-1 C = C
The characteristic absorption based on the double bond and the characteristic absorption of the cyano group at 2220 cm ⁻¹ were exhibited. Further, the ultraviolet-visible absorption spectrum showed a characteristic absorption at 340 cm based on the α-cyanocinnamic acid bond.

1.0 part of the monomer (I) was dissolved in benzene, 0.01 part of azobisisobutyronitrile was added, and the mixture was heated and polymerized at 60 ° C. for 18 hours. After the polymerization, reprecipitation purification was performed to obtain 0.95 part of a polymer (II).

The molecular weight of the obtained polymer in terms of styrene by gel permeation chromatography was 15,000. This polymer exhibits a transition point in glass at 75 ° C., a transition point from a smectic C ^* (S ^* ) liquid crystal structure to a nematic (N) liquid crystal structure at 104 ° C., and a nematic (N) transition at 143 ° C.
The transition point from the liquid crystal structure to the isotropic (I) structure was shown.

This polymer was dissolved in chloroform and applied by a spin coating method to obtain a 2.5 μm coated film. When the obtained coating film was irradiated with ultraviolet light for 1 minute using a 2KW high-pressure mercury lamp, the irradiated portion was insolubilized. In the infrared absorption spectrum of the insolubilized portion, it was confirmed that the intensity of the characteristic absorption at 1610 cm ^-1 based on the C = C double bond of the α-cyanocinnamic acid bond was significantly reduced, and that photocrosslinking had occurred.

Example 2 Among the monomer (I) and the polymer (II), R ₁ = H and R ₂ =
_{- (CH 2) 11 -,} n = 0, X = H and R ₃ ^* = -CH ₂ CH
(CH ₃ ) C ₂ H ₅ will be described.

The α-cyano-p-hydroxycinnamic acid of Example 1 was replaced with p
-Monomer (I) was obtained in the same manner except that hydroxycinnamic acid was replaced. Elemental analysis of this compound gave C7
The values were 2.15% and H 8.30%, showing good agreement with the theoretical values of C 72.64% and H 8.01%. The infrared absorption spectrum showed a characteristic absorption at 1710 cm ^-1 near the ester bond and a characteristic absorption at 1630 cm ^-1 based on the C = C double bond of the cinnamate bond. The ultraviolet-visible absorption spectrum showed an absorption maximum at 310 cm.

Monomer (I), 1.0 part was added to benzoyl peroxide 0.01
A part was dissolved in benzene and reacted by heating at 70 ° C for 24 hours. The polymer (II) is purified by reprecipitation purification of the obtained polymer.
0.83 parts were obtained. The molecular weight of this polymer was 17,000. This polymer showed a liquid crystal phase. This polymer was applied in the same manner as in Example 1, and the resulting coating film was irradiated with ultraviolet light, whereby the irradiated portion was insolubilized.

Example 3 Among the monomer (I) and the polymer (II), R ₁ CHCH ₃ , R _{2
= - (CH 2) 6 -} , n = 1, X = CN and R ₃ ^* = -CH (C
H ₃ ) C ₆ H ₁₃ will be described.

In Example 1, ω-bromoundecanol was used as ω-bromohexanol, α-cyano-p-hydroxycinnamic acid was used as p-hydroxycinnamylideneacetic acid, and 2-methyl-1-butanol was used as (+)-. Monomer (I) was obtained in the same manner as in Example 1 in place of 2-octanol.

The infrared absorption spectrum of this compound shows the characteristic absorption based on the ester at 1710 cm ⁻¹ , the characteristic absorption based on the ester at 2230 cm ⁻¹ , and the characteristic absorption based on the C ＝ C double bond of the cinnammylidene acetate bond near 1610 cm ^−1. Indicated. Elemental analysis values were as follows: C 71.15%, H 7.53%, N 2.15%, theoretical value C7
1.85%, H7.20% and N2.33% showed good agreement.

1.0 part of monomer (I) and 0.0 of azobisisobutyronitrile
One part was dissolved in benzene and polymerized by heating at 60 ° C. for 24 hours to obtain a polymer (II). The molecular weight of this polymer was 12,000. The obtained polymer was applied, the coating film was covered with a negative film, and the film was irradiated with ultraviolet light to obtain a pattern.

Example 4 Among the monomer (I) and the polymer (II), R ₁ = H and R ₂ =
— (CH ₂ ) ₄ —, n = 1, X = H and R ₃ ^* = menthyl group will be described.

The ω-bromoundecanol of Example 1 was replaced with ω-bromobutanol, and α-cyano-p-hydroxycinnamic acid was replaced with p.
-Hydroxycinnamylideneacetic acid to 2-methyl-1-
Monomer (I) was obtained in the same manner as in Example 1, except that butanol was replaced with (+)-menthol.

Infrared absorption spectrum of this compound an absorption based on an ester bond to 1710 cm ^-1, showing a characteristic absorption based on cuminic acid ester bond near 1620 cm ^-1. Ultraviolet-visible absorption showed a characteristic absorption at 350 nm based on cinnamylidene acetate bond. Elemental analysis: C 73.56%, H 7.9
3%, which is in good agreement with the theoretical value of C73.73% and H7.669.

Monomer (I), 1.0 part was azobisisobutyronitrile
0.01 parts and dissolved in benzene and polymerized by heating at 60 ° C for 24 hours.
Polymer (II) was obtained. Its molecular weight was 15,000. When the polymer was applied in the same manner as in Example 1 and irradiated with ultraviolet light, the irradiated portion was insolubilized.

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location C09K 19/38 C09K 19/38 G02F 1/13 500 G02F 1/13 500

Claims (4)

(57) [Claims] (1) The following general formula: And a monomer for producing a liquid crystal-forming polymer. 2. The following general formula: A liquid crystal-forming polymer (II) comprising a repeating unit (A) represented by the formula: 3. A process for producing a liquid crystal-forming polymer (II), comprising subjecting the monomer represented by the general formula (I) to heat polymerization in the presence of a radical polymerization initiator. 4. A pattern forming method comprising irradiating a film comprising the polymer (II) with actinic rays.