JP2007224145A - Trioxetane compound, cationically polymerizable composition, optical film and display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a new oxetane compound that has many numbers of oxetane groups bonded in one molecule and provides a strong polymer by a cationic polymerization and its use. <P>SOLUTION: The oxetane compound is represented by general formula (1) (R is each may be the same or different and is hydrogen, a methyl group or an ethyl group; L<SP>1</SP>is each may be the same or different and is a single bond or -(CH<SB>2</SB>)<SB>n</SB>- (n is an integer of 1-12); X is each may be the same or different and is a single bond, -O-, -O-CO- or -CO-O-; Y is each may be the same or different and is a single bond or -O-; M is each may be the same or different and is represented by formula (2) -P<SP>1</SP>-L<SP>2</SP>-P<SP>2</SP>- or formula (3) -P<SP>1</SP>- (P<SP>1</SP>and P<SP>2</SP>are each separately selected from groups represented by formula (4)); L<SP>2</SP>is a single bond, -CH<SB>2</SB>=CH<SB>2</SB>-, -C≡C-, -O-, -O-CO- or -CO-O-). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a novel compound having three oxetane groups capable of cationic polymerization per molecule, a cationically polymerizable composition containing the compound, an optical film, and a display device provided with the film. In particular, the present invention relates to an oxetane compound in which the number of oxetane groups bonded per molecular weight is large and a strong polymer can be obtained by performing cationic polymerization, and its use.

Curing of resins by irradiating with active energy rays such as ultraviolet rays (UV) and electron beams is fast, and in some cases it can be done without solvent, so it is widely used in various coating, printing, and electronic materials fields. Yes. In these fields, many compounds containing an acryloyl group or a methacryloyl group (hereinafter sometimes referred to as a (meth) acryloyl group together) have been used, but the skin irritation is strong, and air When trying to cure inside, there are problems such as insufficient curing due to inhibition of oxygen and large shrinkage during curing.
As a curing system free from these problems, compounds having a cationic polymerizable vinyl ether group or oxirane group have been studied. However, the vinyl ether group has drawbacks such that the elimination of the group tends to occur during the synthesis of the target derivative, and the oxirane group is difficult to synthesize the derivative because of high reactivity.
In recent years, oxetane groups have been studied as functional groups that can solve the above problems, and many oxetane derivatives have been synthesized (see, for example, Patent Documents 1 to 4).

  On the other hand, in recent years, various retardation films have been actively researched and developed for the purpose of color compensation and viewing angle expansion of a liquid crystal display (LCD) whose performance has been remarkably improved, and many have already been put into practical use. is there. As the retardation film, a precisely stretched polymer film and a film made of a liquid crystal compound are known, but as described above, the performance required for the retardation film used in conjunction with the improvement of the performance of the LCD becomes more severe. Conventional films are no longer sufficient. For this reason, a film obtained by stretching a cycloolefin polymer having a high heat-resistant temperature has been used, but it is difficult to say that the optical compensation function is sufficient.

In a retardation film made of a liquid crystal compound, it is essential that the alignment structure of the liquid crystal fixed after alignment is maintained under actual use conditions. As a method for maintaining the alignment structure of the liquid crystal, a method using a polymerizable liquid crystal compound, a method using a polymer liquid crystal material, and a method using a polymer liquid crystal material having a polymerizable reactive group have been proposed.
As a method using a polymerizable liquid crystal compound, a method in which two or three benzene rings are bonded as an mesogen with an ester group (see, for example, Patent Documents 5 and 6). When these low-molecular liquid crystal compounds are used as a material for a retardation film, a method in which the low-molecular liquid crystal compound is heated and melted and coated on a substrate film in a liquid crystal state can be considered. It is difficult to achieve the required film uniformity and film thickness accuracy. Moreover, when apply | coating on a film substrate as a solution, solution viscosity is low and application | coating itself is difficult in many cases. Therefore, in the specifications of Patent Documents 5 and 6, when a self-supporting retardation film is produced, a liquid crystal material is filled in a glass cell and cured by, for example, irradiation with ultraviolet rays under heating. A method of removing the glass substrate to form a self-supporting retardation film has been proposed, but is more complicated than a method of coating on a film substrate.

As a method using a polymer liquid crystal substance, a liquid crystalline polyester excellent in alignment retention ability has been proposed (for example, see Patent Document 7). However, with the widespread use of mobile devices, the retardation films made of these liquid crystalline polyesters are required to have orientation retention ability and better mechanical strength in more severe use environments.
On the other hand, as a method of using a polymer liquid crystal substance having a polymerizable reactive group, a method of introducing a polymerizable reactive group into a polymer main chain, a method of introducing a monomer unit having a polymerizable reactive group into a side chain (for example, However, in any of these methods, the liquid crystallinity is lowered, so there is a limit to the introduction of a large amount of polymerizable reactive groups until the mechanical strength is sufficiently increased. Other methods are needed.

JP-A-11-106380 JP 2001-163882 A JP 2002-80581A International Publication No. 02/28985 Pamphlet Japanese National Patent Publication No. 11-513019 Japanese National Patent Publication No. 11-513360 JP-A-11-158258 JP-A-9-3454

  An object of the present invention is to provide a novel compound which can easily solve the above-described problems and which has a large number of oxetane groups bonded thereto, a cationically polymerizable composition containing the compound, and heat resistance obtained from the composition An improved optical film is provided.

（式（１）において、Ｒは、それぞれ同じでも異なってもよく、水素、メチル基またはエチル基を表し、Ｌ^１は、それぞれ同じでも異なってもよく、単結合または−（ＣＨ_２）_ｎ−（ｎは１〜１２の整数）を表し、Ｘは、それぞれ同じでも異なってもよく、単結合、−Ｏ−、−Ｏ−ＣＯ−、または−ＣＯ−Ｏ−を表し、Ｙは、それぞれ同じでも異なってもよく、単結合または−Ｏ−を表し、Ｍは、それぞれ同じでも異なってもよく、式（２）または式（３）で表されるいずれかであり、式（２）および式（３）中のＰ^１およびＰ^２は、それぞれ個別に、式（４）から選ばれる基を表し、Ｌ^２は、単結合、−ＣＨ_２＝ＣＨ_２−、−Ｃ≡Ｃ−、−Ｏ−、−Ｏ−ＣＯ−、または−ＣＯ−Ｏ−を表す。）
−Ｐ^１−Ｌ^２−Ｐ^２− （２）
−Ｐ^１− （３）

That is, the first of the present invention relates to a trioxetane compound represented by the following general formula (1).

(In Formula (1), R may be the same or different and each represents hydrogen, a methyl group or an ethyl group, L ¹ may be the same or different, and may be a single bond or — (CH ₂ ) _n —. (N is an integer of 1 to 12), X may be the same or different and each represents a single bond, —O—, —O—CO—, or —CO—O—, and Y is the same. However, they may be different and each represents a single bond or —O—, and M may be the same as or different from each other, and is any one represented by the formula (2) or the formula (3). P ¹ and P ^{2 in} (3) each independently represent a group selected from Formula (4), and L ² represents a single bond, —CH ₂ ═CH ₂ —, —C≡C—, —O. -Represents -O-CO- or -CO-O-.)
-P ¹ -L ² -P ^2- (2)
-P ^1- (3)

According to a second aspect of the present invention, in the general formula (1), L ¹ is — (CH ₂ ) ₂ —, — (CH ₂ ) ₄ —, or — (CH ₂ ) ₆ —, and X is —O The trioxetane compound according to the first aspect of the present invention, which is —CO— or —CO—O—.

  A third aspect of the present invention is a cationically polymerizable composition comprising a trioxetane compound represented by the general formula (1) and a compound having a cationically polymerizable group (excluding the compound represented by the general formula (1)). , Regarding.

  4th of this invention is related with the cationically polymerizable composition as described in 3rd of this invention characterized by containing the trioxetane compound represented by General formula (1) at least 5 mass% or more.

  A fifth aspect of the present invention relates to the cationically polymerizable composition according to the third aspect of the present invention, wherein the compound having a cationically polymerizable group is a compound exhibiting liquid crystallinity.

  A sixth aspect of the present invention relates to the cationically polymerizable composition according to the fifth aspect of the present invention, wherein the compound exhibiting liquid crystallinity is an oligomer or a polymer compound.

  7th of this invention is related with the cationically polymerizable composition in any one of the 3rd-6th of this invention characterized by containing a cationic polymerization initiator.

  8th of this invention is related with the optical film obtained by superposing | polymerizing the cationically polymerizable composition in any one of 3-7 of this invention.

  9th of this invention is related with the display apparatus which has arrange | positioned the optical film as described in 8th of this invention.

  The trioxetane compound of the present invention is a novel compound, is easily synthesized, and an optical film having improved heat resistance and the like can be obtained from a cationically polymerizable composition containing the compound.

Hereinafter, the present invention will be described in detail.
The present invention is a trioxetane compound represented by the following general formula (1).

In the formula (1), R may be the same or different and each represents hydrogen, a methyl group or an ethyl group, and L ¹ may be the same or different and each represents a single bond or — (CH ₂ ) _n — ( n represents an integer of 1 to 12, X may be the same or different, each represents a single bond, —O—, —O—CO—, or —CO—O—, and Y may be the same They may be different and each represents a single bond or —O—, and each M may be the same or different and is represented by formula (2) or formula (3). P ¹ and P ^{2 in} 3) each independently represent a group selected from Formula (4), and L ² represents a single bond, —CH ₂ ═CH ₂ —, —C≡C—, —O—. , -O-CO-, or -CO-O-. )
-P ¹ -L ² -P ^2- (2)
-P ^1- (3)

などが挙げられる。 The compound represented by the general formula (1) can be exemplified by many compounds by selecting L ¹ , X, Y and M, but preferably L ¹ is — (CH ₂ ) ₂ —, — (CH ₂ ). ₄ -, or - _{(CH 2) 6} - and is, X is a -O-CO-, or -CO-O-, compound, more specifically,

Etc.

The oxetane compound of the present invention represented by the formula (1) can be synthesized according to a usual synthesis method in organic chemistry, and the synthesis method is not particularly limited.
In the synthesis, since the oxetane group has cationic polymerizability, it is necessary to select reaction conditions in consideration of causing side reactions such as polymerization and ring opening under strong acidic conditions. Oxetane groups are less likely to cause side reactions than oxirane groups, which are similar cationically polymerizable functional groups. Furthermore, various compounds such as similar alcohols, phenols, carboxylic acids and the like may be reacted one after another, and utilization of protecting groups may be considered as appropriate. The synthesized crude oxetane derivative may be purified by a method such as recrystallization or column chromatography. In particular, recrystallization is an effective means for those having a certain degree of crystallinity, and even a compound that cannot be recrystallized at room temperature can be recrystallized by cooling to a low temperature such as −20 ° C. is there.

  As a specific synthesis method, for example, hydroxybenzoic acid is used as a starting compound, an oxetane group is bonded by, for example, Williamson's ether synthesis method, etc., and then the obtained compound and a triol suitable for the present invention are combined with an acid chloride. Or by condensing using a carbodiimide condensation method or the like, and conversely protecting the hydroxyl group of hydroxybenzoic acid with an appropriate protecting group in advance, condensing with a triol suitable for the present invention, removing the protecting group, and And a method of reacting a hydroxyl group with a oxetane compound such as a haloalkyloxetane.

  For the reaction between the oxetane compound and the hydroxyl group, a reaction condition suitable for the form and reactivity of the compound used may be selected. Usually, the reaction temperature is -20 ° C to 180 ° C, preferably 10 ° C to 150 ° C. The reaction time is 10 minutes to 48 hours, preferably 30 minutes to 24 hours. Outside these ranges, the reaction does not proceed sufficiently or side reactions occur, which is not preferable. Moreover, the mixing ratio of both is preferably 0.8 to 1.2 equivalents of the oxetane compound per equivalent of hydroxyl group.

  The reaction can be carried out without solvent, but is usually carried out in a suitable solvent. The solvent used is not particularly limited as long as it does not interfere with the intended reaction. For example, aromatic hydrocarbons such as benzene, toluene and xylene, amides such as dimethylformamide, dimethylacetamide and N-methylpyrrolidone, methyl ethyl ketone, Examples thereof include ketones such as methyl isobutyl ketone, ethers such as dibutyl ether, ethylene glycol dimethyl ether and diethylene glycol dimethyl ether, esters such as ethyl acetate and ethyl benzoate, and mixtures thereof.

The present invention also relates to a cationically polymerizable composition comprising the trioxetane compound of the present invention and a compound having a cationically polymerizable group.
The cationically polymerizable composition of the present invention comprises the trioxetane compound of the present invention and a compound having a cationically polymerizable group other than the oxetane compound, and preferably contains at least 5% by mass or more of the trioxetane compound of the present invention. Preferably, it is a cationically polymerizable composition containing 10% by mass or more. When the content of the trioxetane compound is less than 5% by mass, the concentration of the polymerizable group in the composition is low, and the mechanical strength after polymerization is not necessarily sufficient, which is not preferable. Although an upper limit is not specifically limited, 80 mass% or less is preferable. When it exceeds 80% by mass, brittleness becomes conspicuous in the crosslinked product, which is not preferable.

  The compound having a cationically polymerizable group blended in the trioxetane compound of the present invention is a compound having a cationically polymerizable group represented by the following formula (5) (however, the trioxetane compound of the present invention is excluded). ), There is no particular limitation as long as it is miscible with the trioxetane compound of the present invention, various low molecular compounds, various high molecular compounds having film forming ability, and various liquid crystalline low molecular compounds exhibiting liquid crystallinity. And liquid crystalline polymer compounds. Furthermore, a compound having no cationically polymerizable group and various dyes, pigments and additives may be blended within a range not impairing the object of the present invention. Among these, a compound exhibiting liquid crystallinity is preferable, and the liquid crystallinity as a whole composition is particularly preferable for the production of an optical film described later.

  There are various types of compounds having a cationic polymerizable group and exhibiting liquid crystallinity, but oligomers and polymer compounds exhibiting liquid crystallinity are preferable. As the liquid crystalline polymer compound, both a main chain type and a side chain type can be used. Examples of the main chain type liquid crystalline polymer compound include polyester, polyesteramide, and polycarbonate, and examples of the side chain type liquid crystalline polymer compound include polyacrylate, polysiloxane, and polymalonate.

  As a method for synthesizing the main-chain liquid crystalline polyester, a method used when synthesizing a normal polyester can be adopted, and the method is not particularly limited. For example, a method in which a carboxylic acid unit is activated to an acid chloride or a sulfonic acid anhydride, and this is reacted with a phenol unit in the presence of a base (acid chloride method), or a carboxylic acid unit and a phenol unit are converted into DCC (dicyclohexylcarbodiimide). A method of directly condensing using a condensing agent such as the above, a method of acetylating a phenol unit, and a method of deaceticating polymerization of this with a carboxylic acid unit under melting conditions can be used. However, in the case of using deacetic acid polymerization under melting conditions, it is necessary to strictly control the reaction conditions because the monomer unit having a cationic polymerizable group may cause polymerization or decomposition reaction under the reaction conditions. In many cases, it is desirable to use a method such as using an appropriate protective group or reacting a compound having another functional group once and then introducing a cationically polymerizable group later. There is also. The crude main chain type liquid crystalline polyester obtained by the polymerization reaction may be purified by a method such as recrystallization or reprecipitation.

  Side chain type liquid crystalline polymer compounds can also be synthesized by various methods. For example, in the case of poly (meth) acrylate, a (liquid crystalline) (meth) acrylic compound having a cationic polymerizable group at one end and liquid crystalline properties A side chain liquid crystalline polymer compound having a cationic polymerizable group can be obtained by polymerizing only a (meth) acrylic group by radical polymerization or anionic polymerization using a (meth) acrylic compound.

  As an example of radical polymerization, a (meth) acrylic compound is dissolved in a solvent such as dimethylformamide (DMF), and 2,2′-azobisisobutyronitrile (AIBN), benzoyl peroxide (BPO), or the like is used as an initiator. The method of making it react at 60-150 degreeC for several hours is mentioned. Moreover, in order to make the liquid crystal phase appear stably, copper bromide (I) / 2,2′-bipyridyl series, 2,2,6,6-tetramethylpiperidinooxy free radical (TEMPO) series, etc. are used. A method of controlling the molecular weight distribution by conducting living radical polymerization as an initiator is also effective. These radical polymerizations must be carried out strictly under deoxygenation conditions.

Examples of anionic polymerization include a method in which a (meth) acrylic compound is dissolved in a solvent such as tetrahydrofuran (THF) and reacted with a strong base such as an organic lithium compound, an organic sodium compound, or a Grignard reagent as an initiator. In addition, the molecular weight distribution can be controlled by optimizing the initiator and the reaction temperature for living anionic polymerization. These anionic polymerizations must be performed strictly under dehydration and deoxygenation conditions.
If necessary, other copolymerizable compounds can be copolymerized. The compound to be copolymerized is not particularly limited, but preferably a (meth) acrylic compound having a mesogenic group is preferred in order to enhance liquid crystallinity by using a compound in which the synthesized polymer compound exhibits liquid crystallinity. .

The method for synthesizing the (meth) acrylic compound having a cationic polymerizable group is not particularly limited, and can be synthesized by applying a method used in a normal organic chemical synthesis method.
For example, by combining a site having a cationic polymerizable group and a site having a (meth) acrylic group by means of Williamson's ether synthesis method or ester synthesis method using a condensing agent, the cationic polymerizable group ( A (meth) acrylic compound having two functional groups completely different from the (meth) acrylic group can be easily synthesized.

Since the cationically polymerizable composition of the present invention comprises a compound having a cationically polymerizable group, it is preferable to add a cationic polymerization initiator for the polymerization (curing).
Cationic polymerization initiators include a photo cation generator capable of generating cations by appropriate light and a thermal cation generator capable of generating cations by heat (hereinafter, both may be referred to as a cation generator). In the cationically polymerizable composition of the present invention, each may be used individually, or both may be used in combination. If necessary, various sensitizers may be used in combination.

More specifically, the photocation generator in the present invention means a compound that generates a cation when irradiated with light of an appropriate wavelength, and is an organic sulfonium salt type, iodonium salt type, phosphonium salt. A system etc. can be illustrated. Antimonates, phosphates, borates and the like are preferably used as counter ions of these compounds. Specific examples of the compound include Ar ₃ S ⁺ SbF ₆ ⁻ , Ar ₃ P ⁺ BF ₄ ⁻ , Ar ₂ I ⁺ PF ₆ ⁻ (wherein Ar represents a phenyl group or a substituted phenyl group), and the like. . In addition, sulfonate esters, triazines, diazomethanes, β-ketosulfone, iminosulfonate, benzoinsulfonate, and the like can also be used.

  The thermal cation generator referred to in the present invention is a compound that generates a cation when heated to an appropriate temperature. For example, benzylsulfonium salts, benzylammonium salts, benzylpyridinium salts, benzylphosphonium salts, hydrazinium salts Carboxylic acid esters, sulfonic acid esters, amine imides, antimony pentachloride-acetyl chloride complexes, diaryliodonium salts-dibenzyloxycopper, boron halide-tertiary amine adducts, and the like.

  Further, a cationically polymerizable composition to which a compound capable of generating a cation such as Lewis acid is added in advance is prepared, and after treatment such as coating and drying, a cation can be generated and polymerized. When the cationic polymerizable composition exhibits liquid crystallinity, a method of polymerizing the cationic polymerizable group after forming the liquid crystal alignment or simultaneously with forming the liquid crystal alignment can be employed, but the liquid crystal alignment step and the polymerization step can be separated. In many cases, sufficient liquid crystal alignment and degree of polymerization can be achieved at the same time. In practice, it is more preferable to use a cation generator that is manifested by heat or light.

  In the case of using a thermal cation generator, heat treatment is performed for the orientation of the cationic polymerizable composition at a temperature lower than the activation temperature of the thermal cation generator (a commonly used index is 50% dissociation temperature). Then, by heating to the activation temperature or higher in this step, the thermal cation generator used can be dissociated, and the cation polymerizable group can be reacted with the generated cations. The merit of this method is that liquid crystal alignment and polymerization reaction can be performed only by heat treatment equipment. However, since the alignment and polymerization processes are separated only by heat (difference in temperature), the polymerization reaction proceeds slightly during alignment, or the reaction may not sufficiently proceed even in the polymerization process. There are also disadvantages.

  When a photo cation generator is used, if the heat treatment for liquid crystal alignment is performed under dark conditions (light blocking conditions that do not allow the photo cation generator to dissociate), the cationic polymerizable composition undergoes polymerization and decomposition at the alignment stage. Without orientation, it can be oriented with sufficient fluidity. Then, the cation is generated by irradiating light from a light source that emits light of an appropriate wavelength, and the cationic polymerizable composition is polymerized (cured).

The amount of these cation generators added to the cationic polymerizable composition varies depending on the compound constituting the cationic polymerizable composition to be used, various additives, oxetane group equivalent, etc. The mass ratio to the composition is usually 100 ppm to 20%, preferably 1000 ppm to 10%, more preferably 0.2% to 7%, and most preferably 0.5% to 5%. If the amount is less than 100 ppm, the amount of cations generated may not be sufficient and polymerization may not proceed. If the amount is more than 20%, the residual cation generator remaining in the cation polymerizable composition may remain decomposed. There is a risk that the light resistance and the like may be deteriorated due to an increase in the number of objects and the like, which is not preferable in either case.
Among the cation generators described above, the photo cation generator capable of generating cations by light is capable of generating cations at an arbitrary temperature at which a liquid crystal phase is developed, such as when the cation polymerizable composition has liquid crystallinity. It is particularly preferable because it can be polymerized (cured).

Thus, an optical film can be produced by polymerizing (curing) the cationically polymerizable composition of the present invention into a thin film.
Next, the manufacturing method of the optical film using the cationically polymerizable composition of this invention is demonstrated in detail. The method for producing the optical film is not limited to these, but it is desirable to take each step shown in the following method.
The optical film produced from the cationic polymerizable composition of the present invention is transferred onto the substrate as it is formed on the substrate (substrate / (alignment film) / optical film), a transparent substrate film different from the substrate, etc. When the optical film has a self-supporting form (transparent substrate film / optical film), the optical film single-layer form (film) may be used.

  As the substrate that can be used in the present invention, in consideration of the case where the cationic polymerizable composition exhibits liquid crystallinity, a substrate that can be an alignment substrate is preferable, and polyimide, polyamide, polyamideimide, polyphenylene sulfide, polyphenylene oxide, Examples thereof include films of polyether ketone, polyether ether ketone, polyether sulfone, polysulfone, polyethylene terephthalate, polyethylene naphthalate, polyarylate, triacetyl cellulose, epoxy resin, phenol resin, and uniaxially stretched films of these films. Some of these films show sufficient ability for the cationic polymerizable composition of the present invention without performing treatment for expressing orientation ability again depending on the production method. If necessary, these films are stretched under moderate heating, the film surface is rubbed in one direction with a rayon cloth or the like, so-called rubbing treatment is performed, and known orientation agents such as polyimide, polyvinyl alcohol, silane coupling agent are applied on the film. Alternatively, a film that exhibits orientation ability by providing an alignment film made of the above, performing a rubbing process, oblique vapor deposition process such as silicon oxide, or a combination thereof may be used. Further, a metal plate such as aluminum, iron, copper, etc., and various glass plates provided with regular fine grooves on the surface can be used as the substrate.

  When using a substrate that is not optically isotropic as the substrate, or the obtained optical film is an opaque substrate in the intended wavelength range of use, an optically isotropic film from the form formed on the substrate A form transferred onto a transparent substrate in a wavelength region to be finally used can also be used. As the transfer method, for example, as described in JP-A-4-57017 and JP-A-5-333313, an optical film layer is bonded to another transparent material different from the original substrate through an adhesive / adhesive. A method of transferring only the optical film by laminating an appropriate substrate, then subjecting the adhesive / adhesive to curing treatment if necessary, and removing the original substrate from the laminate can be exemplified.

  Examples of the transparent substrate include triacetyl cellulose films such as Fujitac (product of Fuji Photo Film Co., Ltd.) and Konicatak (product of Konica Corp.), TPX film (product of Mitsui Chemicals Co., Ltd.), Arton Film (JSR). Products), ZEONEX film (product of Nippon Zeon Co., Ltd.), acrylene film (product of Mitsubishi Rayon Co., Ltd.), etc. A film obtained by stretching a polymer, polyester or the like can also be used. Further, a quartz plate or a glass plate may be used. In addition, the said polarizing plate can be used regardless of the presence or absence of a protective layer.

The adhesive / adhesive used for transfer is not particularly limited as long as it is of optical grade. For example, acrylic, epoxy resin, ethylene-vinyl acetate copolymer system, rubber system, urethane system, and mixtures thereof And various reactive types such as a thermosetting type and / or a photocurable type and an electron beam curable type.
Since the reaction (curing) conditions for the reactive substances vary depending on the components constituting the adhesive / adhesive, the viscosity, the reaction temperature, and the like, conditions suitable for each may be selected. For example, in the case of the photo-curing type, the same light source as in the case of the photocation generator described later may be used, and the same irradiation dose may be used. The acceleration voltage in the case of the electron beam-curing type is usually 10 kV to 200 kV, preferably 25 kV. ~ 100 kV.

  The optical film can be produced by a method of applying the cationic polymerizable composition on the substrate in a molten state, a method of applying a solution of the cationic polymerizable composition on the substrate, or the like. The coating applied on the substrate is subjected to light irradiation and / or heat treatment (polymerization) after operations such as drying, heat treatment and / or stretching, if necessary, to become an optical film.

  The solvent used for preparing the cationic polymerizable composition solution is not particularly limited as long as it is a solvent that can dissolve each component constituting the cationic polymerizable composition of the present invention and can be distilled off under appropriate conditions. Acetone, methyl ethyl ketone, isophorone, cyclohexanone and other ketones, butoxyethyl alcohol, hexyloxyethyl alcohol, ether alcohols such as methoxy-2-propanol, ethylene glycol dimethyl ether, glycol ethers such as diethylene glycol dimethyl ether, ethyl acetate, acetic acid Esters such as methoxypropyl, ethyl lactate and γ-butyrolactone, phenols such as phenol and chlorophenol, N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolide Amides such as chloroform, tetrachloroethane, halogenated hydrocarbons such or a mixture of these systems, such as dichlorobenzene are preferably used. Moreover, in order to form a uniform coating film on a board | substrate, you may add surfactant, an antifoamer, a leveling agent, etc. to a solution. Furthermore, dyes, pigments, and the like can be added for the purpose of coloring within a range not departing from the object of the present invention.

  The application method is not particularly limited as long as the uniformity of the coating film is ensured, and a known method can be adopted. Examples thereof include a roll coating method, a die coating method, a dip coating method, a curtain coating method, and a spin coating method. After the application, a solvent removal (drying) step by a method such as a heater or hot air blowing may be added.

  The coating film thickness is not generally determined because it is adjusted depending on the physical properties (refractive index anisotropy, composition, etc.) of the cationic polymerizable composition to be used and the use of the optical film to be obtained. It is 0.1-20 micrometers, Preferably it is 0.3-10 micrometers. When the cationic polymerizable composition exhibits refractive index anisotropy, the retardation value (refractive index anisotropy value × film thickness: Δnd) is set to 20 to 1000 nm, preferably 50 to 800 nm. Outside this range, it is not preferable because it is difficult to achieve the desired effect.

  Before performing polymerization (curing) by light irradiation and / or heat treatment on the coating film, heat treatment or the like may be performed if necessary. This heat treatment is preferably incorporated when the cationic polymerizable composition exhibits liquid crystallinity, and is heated to the liquid crystal phase expression temperature range of the used cationic polymerizable composition, so that the liquid crystal exhibits the self-orientation ability inherent in the composition. Is oriented. As conditions for the heat treatment, the optimum conditions and limit values differ depending on the liquid crystal phase behavior temperature (transition temperature) of the cationic polymerizable composition to be used, but it cannot be generally stated, but is usually 10 to 250 ° C., preferably 20 to 200 ° C. It is a range. If the temperature is too low, the alignment of the liquid crystal may not proceed sufficiently, and if the temperature is high, the cationically polymerizable group containing the oxetane group or the substrate may be adversely affected. Moreover, about heat processing time, it is 3 seconds-30 minutes normally, Preferably it is the range of 10 seconds-10 minutes. If the heat treatment time is shorter than 3 seconds, the alignment of the liquid crystal may not be sufficiently completed, and if the heat treatment time exceeds 30 minutes, productivity is extremely deteriorated. After the alignment of the liquid crystal is completed by heat treatment or the like of the cationic polymerizable composition, the composition on the substrate is cured by a polymerization reaction as it is. The purpose of the polymerization / curing step in the present invention is to fix the applied film to a stronger film by fixing the liquid crystal alignment state by polymerization / curing reaction.

  When a photocation generator is used, light is emitted from a light source that emits light of an appropriate wavelength in order to generate cations. As a method of light irradiation, the optimum value of irradiation wavelength, irradiation intensity, irradiation time, etc. varies depending on the type and amount of the photocation generator used, but a metal halide lamp having a spectrum near the absorption wavelength region of the photocation generator. The photocation generator is cleaved by irradiating light from a light source such as a high pressure mercury lamp, a low pressure mercury lamp, a xenon lamp, an arc lamp, a laser, or a synchrotron radiation source. The amount of irradiation per unit area (one square centimeter) is usually in the range of 1 to 2000 mJ, preferably 10 to 1000 mJ as the integrated irradiation amount. However, this is not the case when the absorption region of the photocation generator and the spectrum of the light source are significantly different, or when the cationic polymerizable composition itself has the ability to absorb the light source wavelength. In these cases, an appropriate photosensitizer, or a method of using a mixture of two or more photocation generators having different absorption wavelengths can be used.

  The optical film of the present invention produced by the above process is a sufficiently strong film. Specifically, it is three-dimensionally bonded by the curing reaction, not only improving heat resistance compared to before curing, but also greatly improving mechanical strength such as scratch resistance, abrasion resistance, crack resistance, etc. To do. The present invention has industrial significance in the sense of providing a method capable of achieving strict alignment control of liquid crystal alignment when the cationic polymerizable composition has liquid crystallinity as well as the purpose of improving thermal and mechanical strength. large.

In addition, when the cationic polymerizable composition of the present invention has liquid crystallinity, the alignment structure can be controlled by appropriately selecting the compound to be blended as necessary, and nematic alignment, twisted nematic alignment, cholesteric It is possible to produce a retardation film in which orientation, nematic hybrid orientation, etc. are fixed, and there are various uses depending on the orientation structure.
Among these retardation films, for example, a retardation film in which nematic alignment or twisted nematic alignment is fixed is a compensation plate for a transmissive or reflective liquid crystal display device such as STN type, TN type, OCB type, and HAN type. Can be used as Retardation film with fixed cholesteric orientation is used for various reflective elements such as polarized reflection films for improving brightness, reflective color filters, and various security elements and decorative films that take advantage of the color change of reflected light depending on the viewing angle due to selective reflectivity. Available. Films with a fixed nematic hybrid orientation use the retardation when viewed from the front, and take advantage of the asymmetry due to the direction of the retardation value (film tilt) to improve the viewing angle of TN liquid crystal display devices. It can be used for films. In addition, a retardation film having a 1/4 wavelength plate function can be combined with a polarizing plate and used as an antireflection filter for a reflective liquid crystal display device or an EL display device.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In addition, each analysis method used in the Example is as follows.

(1) Measurement of ¹ H-NMR and ¹³ C-NMR The compound was dissolved in deuterated chloroform or deuterated dimethyl sulfoxide, and measured with INOVA 400 manufactured by VARIAN.
(2) Observation of liquid crystal phase behavior The phase behavior was observed on a hot stage FP82HT manufactured by Mettler, with an ECLIPSE E600POL polarizing microscope manufactured by Nikon Corporation while heating the sample.
The phase transition temperature was measured with a differential scanning calorimeter DSC7 manufactured by Perkin-Elmer.
In the description of the phase behavior, C represents a crystalline phase, Ch represents a cholesteric phase, Nm represents a nematic phase, and Iso represents an isotropic liquid phase.
(3) Parameter measurement of optical film The retardation value (Δnd) of nematic alignment was measured using KOBRA-20ADH manufactured by Oji Scientific Instruments.
The average tilt angle of the nematic hybrid orientation was measured using a KOBRA-20ADH manufactured by Oji Scientific Instruments Co., Ltd., and the retardation value was measured linearly in increments of 10 ° from −50 ° to 50 °. Then, it was obtained by the assumed simulation. The measurement wavelength was 550 nm.
The twist angle and Δnd of the twisted nematic structure were measured using Optipro manufactured by Shintech Co., Ltd.

(4) Measurement of GPC The compound was dissolved in tetrahydrofuran, and TSK-GEL SuperH1000, SuperH2000, SuperH3000, and SuperH4000 were connected in series with an 8020 GPC system manufactured by Tosoh Corporation and measured using tetrahydrofuran as an eluent. Polystyrene standards were used for molecular weight calibration.
(5) Measurement of transmission spectrum The transmission spectrum was measured using an ultraviolet / visible / near infrared spectrophotometer V-570 manufactured by JASCO Corporation.
(6) Film thickness measurement SURFACE TEXTURE ANALYSIS SYSTEM Dektak 3030ST made by SLOAN was used. Moreover, the method of calculating | requiring a film thickness from the data of interference wave measurement (The JASCO Corporation UV / visible / near infrared spectrophotometer V-570) and refractive index data was used together.

In addition, the symbol used in the following reference examples, examples, and comparative examples is shown below.
DCC: 1,3-dicyclohexylcarbodiimide DMAP: 4-dimethylaminopyridine
DCM: Dichloromethane PPTS: Pyridinium-p-toluenesulfonate THF: Tetrahydrofuran DMF: Dimethylformamide BHT: 2,6-Di-t-butyl-4-methylphenol

[Reference Example 1 (Synthesis of Acrylic Compound 1)]
According to the following scheme 1, acrylic compound 1 was synthesized using 3-ethyl-3-hydroxymethyloxetane (trade name OXT-101, manufactured by Toagosei Co., Ltd.) as a raw material.

[Reference Example 2 (Synthesis of Acrylic Compound 2)]
Acrylic compound 2 was synthesized according to Scheme 2.

[Reference Example 3 (Synthesis of Acrylic Compound 3)]
Acrylic compound 3 was synthesized according to Scheme 3.

[Reference Example 4 (Synthesis of Acrylic Compound 4)]
According to Scheme 4, acrylic compound 4 was synthesized.

[Reference Example 5 (Synthesis of side chain liquid crystalline polyacrylate 5)]
From 2 parts (molar ratio) of acrylic compound 1 and 8 parts (molar ratio) of acrylic compound 2, 2,2′-azobisisobutyronitrile as an initiator and DMF as a solvent at 90 ° C. under nitrogen, Side chain type liquid crystalline polyacrylate 5 was synthesized by performing radical polymerization for 6 hours, reprecipitation in methanol and purification.
The weight average molecular weight of the side chain type liquid crystalline polyacrylate 5 measured by GPC was 9,100.
From the DSC measurement, the glass transition point (Tg) was 82 ° C. From a polarizing microscope observation on a hot stage, a nematic liquid crystal phase was developed at a temperature of Tg or higher, and the Nm-Iso transition temperature was 248 ° C.

[Reference Example 6 (Synthesis of side chain type liquid crystalline polyacrylate 6)]
From 2 parts (molar ratio) of acrylic compound 1, 6 parts (molar ratio) of acrylic compound 2 and 2 parts (molar ratio) of acrylic compound 3, 2,2′-azobisisobutyronitrile is used as an initiator, Side chain liquid crystalline polyacrylate 6 was synthesized by performing radical polymerization at 90 ° C. for 6 hours under nitrogen using DMF as a solvent, reprecipitating in methanol and purifying.
The weight average molecular weight of the side chain type liquid crystalline polyacrylate 6 measured by GPC was 9,700.
From the DSC measurement, the glass transition point (Tg) was 78 ° C. From a polarizing microscope observation on a hot stage, a nematic liquid crystal phase was developed at a temperature of Tg or higher, and the Nm-Iso transition temperature was 229 ° C.

[Reference Example 7 (Synthesis of side chain liquid crystalline polyacrylate 7)]
2,2′-azobisisobutyronitrile from 2 parts (molar ratio) of acrylic compound 1, 7.3 parts (molar ratio) of acrylic compound 2 and 0.7 part (molar ratio) of acrylic compound 4 As a initiator, DMF was used as a solvent, radical polymerization was carried out under nitrogen at 90 ° C. for 6 hours, and then reprecipitation in methanol for purification, thereby synthesizing a side-chain liquid crystalline polyacrylate 7.
The weight average molecular weight of the side chain type liquid crystalline polyacrylate 7 measured by GPC was 8,900.
From the DSC measurement, the glass transition point (Tg) was 85 ° C. From observation with a polarizing microscope on a hot stage, a cholesteric liquid crystal phase was developed at a temperature of Tg or higher, and a Ch-Iso transition temperature was 218 ° C.

[Example 1 (Synthesis of Oxetane Compound 1)]

According to Scheme 5 above, oxetane compound 1 was synthesized using 3-ethyl-3-hydroxymethyloxetane, dibromobutane, ethyl p-hydroxybenzoate, and 1,2,4-benzenetriol as raw materials. The obtained compound was purified by silica gel chromatography using a hexane / ethyl acetate solvent.
The purified compound was identified by ¹ H-NMR and ¹³ C-NMR and confirmed to be oxetane compound 1. FIG. 1 shows the ¹ H-NMR spectrum.

(1) Peak position of oxetane compound 1 in ¹ H-NMR (CDCl ₃ ; TMS) δ 0.8 (t, 9H), 1.6 (m, 12H), 1.9 (m, 6H), 3.5 (t, 12H), 3.9 (m, 4H), 4.0 (m, 2H), 4.3 (m, 6H), 4.4 (m, 6H), 6.6-7.2 (m, 2H), 6.8 (m 6H), 7.9 (m, 6H), 8.1 (d, 1H)
(2) Peak position of oxetane compound 1 in ¹³ C-NMR (CDCl ₃ ; TMS) δ 8.44, 26.28, 26.38, 27.02, 43.62, 68.18, 68.24, 71.25, 73.68, 73.70, 78.76, 78.79, 111.08, 113.46, 114.36 , 114.39, 114.44, 114.55, 117.73, 119.81, 120.99, 121.12, 121.16, 121.33, 121.53, 123.94, 124.00, 131.80, 132.47, 132.53, 132.58, 136.03, 140.45, 143.16, 143.27, 148.72, 154.66, 163.52, 3.6.60, 163.52, 3.6163 , 163.69, 163.74, 163.86, 164.14, 164.17, 164.66, 164.77.

[Example 2 (Synthesis of Oxetane Compound 2)]

According to Scheme 6 above, oxetane compound 2 was synthesized using 3-ethyl-3-hydroxymethyloxetane, dibromobutane, ethyl p-hydroxybenzoate, and 1,2,4-benzenetriol as raw materials. The obtained compound was purified by silica gel chromatography using a hexane / ethyl acetate solvent.
The purified compound was identified by ¹ H-NMR and ¹³ C-NMR and confirmed to be oxetane compound 2. FIG. 2 shows the ¹ H-NMR spectrum.

(1) Peak position δ 0.9 (t, 9H), 1.9 (m, 6H), 4.1 (s, 2H), 4.1 (s, 2H), 4.2 in ¹ H-NMR (CDCl ₃ ; TMS) (s, 2H), 4.5-4.6 (m, 12H), 6.9 (d, 2H), 6.9 (d, 2H), 7.0 (d, 2H), 7.2 (dd, 1H), 7.3 (d, 1H), 7.4 (d, 1H), 8.0 (d, 2H), 8.1 (d, 2H), 8.2 (d, 2H);
(2) Peak position δ 8.23, 8.25, 26.65, 26.69, 43.15, 43.13, 43.18, 70.46, 70.50, 77.96, 78.03, 114.34, 114.42, 117.52, 119.64 in ¹³ C-NMR (CDCl ₃ ; TMS) , 121.30, 121.43, 121.82, 123.75, 132.42, 140.21, 142.90, 148.51, 163.34, 163.37, 163.42, 163.51, 163.79, 164.33.

[Example 3 (Creation of optical film)]
0.8 g of the side chain type liquid crystalline polyacrylate 5 synthesized in Reference Example 5 and 0.2 g of the oxetane compound 1 obtained in Example 1 were dissolved in 9 ml of cyclohexanone, and triallylsulfonium hexaxa in the dark. After adding 0.05 g of fluoroantimonate 50% propylene carbonate solution (manufactured by Aldrich, reagent), the insoluble matter was filtered through a polytetrafluoroethylene filter having a pore size of 0.45 μm to prepare a solution of a cationic polymerizable composition. did.
This solution was applied onto a 100 μm-thick polyimide film “Kapton” (manufactured by DuPont) whose surface was rubbed with a rayon cloth, and dried on a hot plate at 60 ° C. after the application. The cationic polymerizable composition layer on the obtained polyimide film was heated to 145 ° C., irradiated with ultraviolet light with an integrated irradiation amount of 300 mJ / cm ^{2 with} a high-pressure mercury lamp in an air atmosphere, and then cooled and cured. A polymerizable composition layer was obtained.

Since the polyimide film used as the substrate is brown and is not preferable as an optical film, the resulting film is subjected to a triacetyl cellulose (TAC) film via an ultraviolet curable adhesive UV-3400 (manufactured by Toa Gosei Co., Ltd.). To obtain an optical film 1. That is, UV-3400 is applied on the cured cationic polymerizable composition layer on the polyimide film so as to have a thickness of 5 μm, laminated with a TAC film, and 400 mJ / cm ² of ultraviolet light is applied from the TAC film side. After irradiating and curing the adhesive, the polyimide film was peeled off.
When the obtained optical film 1 was observed under a polarizing microscope, a monodomain uniform nematic hybrid liquid crystal alignment without disclination was observed, and Δnd when viewed from the front was 120 nm. Further, Δnd when viewed from a position inclined by 40 ° from the vertical along the rubbing axis is 153 nm, and Δnd when viewed from a position inclined by −40 ° on the opposite side is 61 nm, which is asymmetric. Since the point which becomes 0 nm did not exist, it turns out that this film has taken the nematic hybrid orientation structure.
Furthermore, when only the cationic polymerizable composition part of the optical film 1 was scraped off and the glass transition point (Tg) was measured using DSC, Tg was not observed.

This film is affixed to 2 mm thick soda glass via a non-carrier adhesive, and the rubbing direction of the polyimide film is aligned with the absorption axis of the polarizing plate, and a polarizing plate (SQW-862 manufactured by Sumitomo Chemical Co., Ltd.) is used. Pasted. When this sample was observed on a backlight through a polarizing plate, it was a uniform film without unevenness. This sample was allowed to pass for 24 hours in a constant temperature bath at 100 ° C., and then taken out and observed in the same manner. As a result, there was no particular change, and no disturbance in liquid crystal alignment was observed.
The pencil hardness of the surface of the cationic polymerizable composition layer of the film was about 3H, and a sufficiently strong film was obtained. Thus, it was found that by using the side chain type liquid crystalline polyacrylate 5, it is possible to create an optical film that maintains good liquid crystal alignment and is excellent in thermal stability and strength after fixing the liquid crystal alignment.

[Comparative Example 1]
1 g of the side chain type liquid crystalline polyacrylate 4 synthesized in Reference Example 5 was dissolved in 9 ml of cyclohexanone, and 0.05 g of a triallylsulfonium hexafluoroantimonate 50% propylene carbonate solution (aldrich, reagent) in the dark. Then, the insoluble matter was filtered through a polytetrafluoroethylene filter having a pore diameter of 0.45 μm to prepare a liquid crystal material solution.
An oriented film 2 was obtained in the same manner as in Example 3 except that this solution was used.
When the obtained alignment film 2 was observed under a polarizing microscope, a monodomain uniform nematic liquid crystal alignment without disclination was observed, and its Δnd was 100 nm. However, when only the liquid crystal material layer portion of the alignment film 2 is scraped and the glass transition point is measured using DSC, the Tg is as low as 90 ° C. and the pencil hardness of the liquid crystal material layer surface of the film is as soft as HB. was.
This film is affixed to 2 mm thick soda glass with a non-carrier adhesive, and the rubbing direction of the polyimide film and the absorption axis of the polarizing plate are aligned with each other to obtain a polarizing plate (SQW-862, manufactured by Sumitomo Chemical Co., Ltd.). Was pasted. When this sample was observed on a backlight through a polarizing plate, it was a uniform film without unevenness. This sample was allowed to elapse for 24 hours in a 100 ° C. constant temperature bath, then taken out and observed in the same manner. As a result, the liquid crystal alignment was significantly disturbed and white spots were generated.

[Example 4 (Production of retardation film using side-chain liquid crystalline polyacrylate 5)]
5.00 g of side chain type liquid crystalline polyacrylate 5 synthesized in Reference Example 5 and 1.00 g of oxetane compound 2 were taken and dissolved in 35.0 g of cyclohexanone. To this solution, 0.06 g of Dow Chemical UVI-6992 (50% propylene carbonate solution) was added, and the insoluble matter was filtered through a polytetrafluoroethylene filter having a pore size of 0.45 μm to obtain a solution of the cationic polymerizable composition. Prepared.
This solution was applied onto a polyethylene naphthalate film “Teonex Q-51” (manufactured by Teijin Ltd.) having a thickness of 50 μm whose surface was rubbed with a rayon cloth using a spin coating method. The solvent was removed by gently blowing air, and then heated in an oven at 150 ° C. for 3 minutes to form a uniform liquid crystal alignment (film 3a). The pencil hardness on the surface of the film 3a was as weak as 6B or less.

In order to obtain a cured cationic polymerizable composition layer, the film 3a was irradiated with ultraviolet light having an integrated irradiation amount of 450 mJ / cm ² by a high-pressure mercury lamp to obtain a cured cationic polymerizable composition layer (film 3b). Since the polyethylene naphthalate film used as the substrate is not preferable because it has birefringence, the film 3b is transferred onto the TAC film via an ultraviolet curable adhesive “UV-3400” (manufactured by Toagosei Co., Ltd.) and optically used. Film 3 was obtained. For transfer, UV-3400 was applied on the cured cationic polymerizable composition layer on the polyethylene naphthalate film to a thickness of 5 μm, laminated with a TAC film, and 400 mJ / cm ² of ultraviolet light was applied from the TAC film side. The polyethylene naphthalate film was peeled off after curing the adhesive by irradiation.
When the optical film 3 was observed under a polarizing microscope, it had a uniform liquid crystal alignment. Moreover, (DELTA) nd seen from the front of the optical film 3 was 98 nm. Further, only the cationic polymerizable composition layer portion of the optical film 3 was scraped off, and the glass transition point (Tg) was measured by DSC. The Tg was 130 ° C. When the pencil hardness of the surface of the cationic polymerizable composition layer of the optical film 3 was measured, it was about 2H, and a strong film was obtained.

[Example 5 (Preparation of optical film)]
0.9 g of the side chain type liquid crystalline polyacrylate 7 synthesized in Reference Example 7 and 0.1 g of the oxetane compound 1 obtained in Example 1 were dissolved in 9 ml of cyclohexanone, and triallylsulfonium hexaxa in the dark. After adding 0.05 g of fluoroantimonate 50% propylene carbonate solution (manufactured by Aldrich, reagent), the insoluble matter was filtered through a polytetrafluoroethylene filter having a pore size of 0.45 μm to prepare a solution of a cationic polymerizable composition. did.
This solution was applied onto a 50 μm thick polyethylene naphthalate film “Teonex Q-51” (manufactured by Teijin Limited) whose surface was rubbed with a rayon cloth using a spin coating method. Dry above. While the cationic polymerizable composition layer on the obtained polyethylene naphthalate film was heated to 150 ° C., it was irradiated with ultraviolet light with an integrated irradiation amount of 300 mJ / cm ^{2 in} an air atmosphere and then cooled and cured. A cationically polymerizable composition layer was obtained.

In addition, since the polyethylene naphthalate film used as the substrate is not preferable because it has birefringence, the obtained film is triacetylcellulose (TAC) via UV curable adhesive UV-3400 (manufactured by Toagosei Co., Ltd.). It transferred to the film and the optical film 4 was obtained. That is, UV-3400 is applied on the cured cationic polymerizable composition layer on the polyimide film so as to have a thickness of 5 μm, laminated with a TAC film, and 400 mJ / cm ² of ultraviolet light is applied from the TAC film side. After irradiation and curing the adhesive, the polyethylene naphthalate film was peeled off.

When the obtained optical film 4 was observed with a polarizing microscope, uniform cholesteric alignment of monodomains without disclination was observed. Further, when this film is viewed from the front, it has selective reflection light peculiar to cholesteric, and when the transmission spectrum is evaluated by a spectroscope, a reduced light transmission region derived from selective reflection is seen around 530 nm of the visible light region. It was.
Furthermore, when only the cationic polymerizable composition layer portion of the optical film 4 was scraped and the glass transition point (Tg) was measured using DSC, Tg was not observed.
This film was affixed to a 2 mm thick soda glass with a non-carrier adhesive, and the rubbing direction of the polyethylene naphthalate film was aligned with the absorption axis of the polarizing plate to obtain a polarizing plate (SQW-862 manufactured by Sumitomo Chemical Co., Ltd.). ) Was pasted. When this sample was observed on a backlight through a polarizing plate, it was a uniform film without unevenness. This sample was allowed to pass for 24 hours in a constant temperature bath at 100 ° C., and then taken out and observed in the same manner. As a result, there was no particular change, and no disturbance in liquid crystal alignment was observed.
The pencil hardness of the surface of the cationic polymerizable composition layer of the film was about 2H, and a sufficiently strong film was obtained. Thus, it was found that by using the side chain type liquid crystalline polyacrylate 7, it is possible to maintain an excellent liquid crystal orientation and to produce an optical film excellent in thermal stability and strength after fixing the liquid crystal orientation.

[Example 6 (Creation of retardation film using side-chain liquid crystalline polyacrylate 6)]
10.0 g of the side chain type liquid crystalline polyacrylate 6 synthesized in Reference Example 6 and 2.0 g of oxetane compound 2 were taken and dissolved in 20 g of N-methyl-2-pyrrolidone. To this solution, 1.2 g of UVI-6992 (50% propylene carbonate solution) manufactured by Dow Chemical Co. was added, and the insoluble matter was filtered through a polytetrafluoroethylene filter having a pore size of 0.45 μm. Was prepared.
This solution was applied onto a polyethylene naphthalate film “Teonex Q-51” (manufactured by Teijin Ltd.) having a thickness of 50 μm whose surface was rubbed with a rayon cloth using a spin coating method. The solvent was removed by gently blowing air, and then heated in an oven at 150 ° C. for 10 minutes to form a uniform liquid crystal alignment (film 5).

In order to obtain a cured cationically polymerizable composition layer, the film 5 was irradiated with ultraviolet light having an integrated irradiation amount of 600 mJ / cm ^{2 with} a high-pressure mercury lamp to obtain a cured cationically polymerizable composition layer. In addition, since the polyethylene naphthalate film used as a substrate is not preferable because it has birefringence, the film 5 is transferred onto a TAC film via an ultraviolet curable adhesive “UV-3400” (manufactured by Toagosei Co., Ltd.) and optically used. Film 5 was obtained. For transfer, UV-3400 was applied on the cured cationic polymerizable composition layer on the polyethylene naphthalate film to a thickness of 5 μm, laminated with a TAC film, and 400 mJ / cm ² of ultraviolet light was applied from the TAC film side. The polyethylene naphthalate film was peeled off after curing the adhesive by irradiation.
When the optical film 5 was observed under a polarizing microscope, it had a uniform liquid crystal alignment. Further, Δnd viewed from the front of the optical film 5 was 350 nm. Further, only the cationic polymerizable composition layer portion of the optical film 5 was scraped, and when the glass transition point (Tg) was measured by DSC, Tg was not observed. When the pencil hardness of the surface of the cationic polymerizable composition layer of the optical film 5 was measured, it was about 3H, and a strong film was obtained.

[Example 7]
A transflective liquid crystal display device was produced using the optical film 1 obtained in Example 3, and the viewing angle characteristics were examined.
FIG. 3 shows an outline of a cross section of the produced transflective liquid crystal display device.
The second substrate 8 is provided with a reflective electrode 6 made of a material having a high reflectance such as Al and a transmissive electrode 7 made of a material having a high transmittance such as ITO, and the counter electrode is provided on the first substrate 3. 4, and a liquid crystal layer 5 made of a liquid crystal material exhibiting positive dielectric anisotropy is sandwiched between the reflective electrode 6 and the transmissive electrode 7 and the counter electrode 4. A first optical anisotropic element 2 (consisting of polymer stretched films 13 and 14) and a polarizing plate 1 are provided on the opposite surface of the first substrate 3 to the side on which the counter electrode 4 is formed. A second optical anisotropic element 9 (consisting of a liquid crystal film 15 and a polymer stretched film 16) and a polarizing plate 10 are provided on the opposite side of the surface of the substrate 8 on which the reflective electrode 6 and the transmissive electrode 7 are formed. A backlight 11 is provided on the back side of the polarizing plate 10.

The liquid crystal cell 12 used is ZLI-1695 (manufactured by Merck) as the liquid crystal material, and the liquid crystal layer thickness is 2.4 μm in the reflective electrode region 6 (reflective display portion) and 4 in the transmissive electrode region 7 (transmissive display portion). .8 μm. The pretilt angle at the substrate interface of the liquid crystal layer was 2 degrees, and Δnd of the liquid crystal cell was about 150 nm in the reflective display portion and about 300 nm in the transmissive display portion.
A polarizing plate 1 (thickness: about 180 μm; SQW-862 manufactured by Sumitomo Chemical Co., Ltd.) is disposed on the viewer side (upper side of the drawing) of the liquid crystal cell 12, and the first polarizing plate 1 and the liquid crystal cell 12 have a first As the optical anisotropic element 2, polymer stretched films 13 and 14 made of a uniaxially stretched polycarbonate film were disposed. Δnd of the polymer stretched film 13 was approximately 268 nm, and Δnd of the polymer stretched film 14 was approximately 98 nm.
Further, as the second optical anisotropic element 9, a liquid crystal film 15 and a polymer stretched film 16 made of a uniaxially stretched polycarbonate film are disposed behind the liquid crystal cell 12 as viewed from the observer, and a polarizing plate 10 is further disposed on the back. Arranged. The liquid crystal film 15 is the optical film 1 in which the hybrid alignment obtained in Example 3 is fixed, Δnd is 120 nm, and the average tilt angle is 28 degrees. Furthermore, Δnd of the polymer stretched film 16 was 272 nm.

The absorption axes of the polarizing plates 1 and 10, the slow axes of the polymer stretched films 13, 14 and 16, the pretilt direction of both interfaces of the liquid crystal cell 12, and the tilt direction of the liquid crystal film 15 were arranged under the conditions described in FIG.
The polycarbonate 15 (Δnd is approximately 137 nm) is used instead of the optical film 1, and the absorption axis of the polarizing plate 10 disposed on the back side of the liquid crystal cell 12 and the slow axes of the polymer stretched films 15 and 16 are shown in FIG. Comparing iso-contrast curves in all directions when arranged under conditions, it was confirmed that by using the optical film 1, a viewing angle characteristic of about 20 ° spreads.

The ¹ H-NMR spectrum of the trioxetane compound 1 obtained in Example 1 is shown. In addition, the x mark in a figure is the peak of ethyl acetate which is a solvent used for refinement | purification. The ¹ H-NMR spectrum of the trioxetane compound 1 obtained in Example 2 is shown. In addition, the x mark in a figure is the peak of ethyl acetate which is a solvent used for refinement | purification. FIG. 6 shows a schematic cross-sectional schematic view of a transflective liquid crystal display device fabricated in Example 7. FIG. The schematic diagram showing the axial arrangement | positioning of each layer of Example 7 is shown. The schematic diagram showing the axial arrangement | positioning of each layer used as the comparative example of Example 7 is shown.

Explanation of symbols

1,10 Polarizing plate
2 First optical anisotropic element 3 First substrate 4 Counter electrode 5 Liquid crystal layer (for driving)
6 reflective electrode 7 transmissive electrode 8 second substrate 9 second optical anisotropic element 11 backlight 12 liquid crystal cell 13, 14, 16 polymer stretched film 15 liquid crystal film (or polymer stretched film)

Claims (9)

A trioxetane compound represented by the following general formula (1).

(In Formula (1), R may be the same or different and each represents hydrogen, a methyl group or an ethyl group, L ¹ may be the same or different, and may be a single bond or — (CH ₂ ) _n —. (N is an integer of 1 to 12), X may be the same or different and each represents a single bond, —O—, —O—CO—, or —CO—O—, and Y is the same. However, they may be different and each represents a single bond or —O—, and M may be the same as or different from each other, and is any one represented by the formula (2) or the formula (3). P ¹ and P ^{2 in} (3) each independently represent a group selected from Formula (4), and L ² represents a single bond, —CH ₂ ═CH ₂ —, —C≡C—, —O. -Represents -O-CO- or -CO-O-.)
-P ¹ -L ² -P ^2- (2)
-P ^1- (3)

In General Formula (1), L ¹ is — (CH ₂ ) ₂ —, — (CH ₂ ) ₄ —, or — (CH ₂ ) ₆ —, and X is —O—CO— or —CO The trioxetane compound according to claim 1, which is -O-.   A cationically polymerizable composition comprising a trioxetane compound represented by the general formula (1) and a compound having a cationically polymerizable group (excluding the compound represented by the general formula (1)).   The cationically polymerizable composition according to claim 3, comprising at least 5% by mass of the trioxetane compound represented by the general formula (1).   The cationically polymerizable composition according to claim 3, wherein the compound having a cationically polymerizable group is a compound exhibiting liquid crystallinity.   6. The cationically polymerizable composition according to claim 5, wherein the compound exhibiting liquid crystallinity is an oligomer or a polymer compound.   The cationic polymerizable composition according to claim 3, further comprising a cationic polymerization initiator.   The optical film obtained by superposing | polymerizing the cationically polymerizable composition in any one of Claims 3-7. The display apparatus which has arrange | positioned the optical film of Claim 8.

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