JP2014174321A - Production method of optical film having surface shape, polymerizable liquid crystal film, and polymerizable liquid crystal film having surface shape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method of an optical film having a surface shape in which high heat resistance is achieved and the surface shape can be easily imparted, and to provide a polymerizable liquid crystal film and an optical film having a surface shape.SOLUTION: The production method of an optical film having a surface shape includes the following steps (1), (2) and (4). They are: (1) a step of applying a polymerizable liquid crystal composition on a base film to form a polymerizable liquid crystal layer; (2) a step of half curing the polymerizable liquid crystal layer; and (4) a step of imparting a surface shape to the half-cured polymerizable liquid crystal layer.

Description

  The present invention relates to a method for producing an optical film having a surface shape, a polymerizable liquid crystal film, and an optical film having a surface shape.

  A liquid crystal film obtained by curing a polymerizable liquid crystal compound such as a cholesteric liquid crystal compound can selectively reflect circularly polarized light, and thus is used in various applications such as a brightness enhancement film and an infrared reflection film in a display. (Patent Document 1). Furthermore, it is known to impart a function such as diffraction by imparting a surface shape such as a diffraction pattern to a liquid crystal film (Patent Document 2).

JP-A-8-271731 JP 2000-310704 A

  However, as in Patent Document 2, when a surface shape is imparted under heat and pressure, the shape imparted liquid crystalline film may be damaged at high temperatures or may be discolored when the surface shape is imparted. There was sex. In particular, when the surface shape was given above the glass transition temperature of the liquid crystalline layer, there was a problem with the heat resistance of the produced liquid crystalline film.

  The objective of this invention is providing the manufacturing method of the optical film which has high heat resistance and has a surface shape which can provide a surface shape easily, a polymeric liquid crystal film, and the optical film which has a surface shape.

As a result of investigations to solve the above-mentioned problems, the present inventor found that the problems can be solved by manufacturing by a predetermined manufacturing method, and completed the present invention.
That is, according to the present invention, the following [1] to [7] are provided.

[1] A method for producing an optical film having a surface shape, comprising the following steps (1), (2), and (4):
(1) A step of forming a polymerizable liquid crystal layer by applying a polymerizable liquid crystal composition to a base film.
(2) A step of semi-curing the polymerizable liquid crystal layer.
(4) A step of imparting a surface shape to the semi-cured polymerizable liquid crystal layer.

[2] The method for producing an optical film according to [1], further comprising the following step (3) after the step (2) and before the step (4).
(3) A step of transferring the semi-cured polymerizable liquid crystal layer to a transfer substrate film.

[3] The method for producing an optical film as described in [1] or [2], further comprising the following steps.
(5) A step of fully curing the polymerizable liquid crystal layer imparted with the surface shape.

[4] A polymerizable liquid crystal film produced by the steps (1) to (2).
[5] A film having a polymerizable liquid crystal layer having a surface shape produced by the method of [1] or [2].
[6] An optical film having a surface shape produced by the steps (1) to (5).
[7] An optical film having a surface shape produced by the steps (1), (2), (4), and (5).

  The optical film obtained by the method for producing an optical film having a surface shape of the present invention is excellent in heat resistance, and an optical film having a surface shape can be easily produced by the production method of the present invention.

It is drawing which shows typically 1st embodiment of the manufacturing method of this invention. It is drawing which shows the example of the process of this hardening typically. It is drawing which shows 2nd embodiment of the manufacturing method of this invention typically.

  Hereinafter, the present invention will be described in detail with reference to embodiments and examples, but the present invention is not limited to the following embodiments and examples, and the claims of the present invention and equivalents thereof. Any change can be made without departing from the scope described above.

[First embodiment]
In the production method of the first embodiment of the present invention, a polymerizable liquid crystal composition is applied on a base film, a polymerizable liquid crystal layer is formed, semi-cured by light or heat, and semi-cured. It is characterized in that it includes a step of imparting a surface shape to the liquid crystal layer by a physical or chemical method. Furthermore, it is preferable to include a step of fully curing the polymerizable liquid crystal layer imparted with the surface shape.

  The first embodiment will be described more specifically with reference to the drawings. First, as shown in FIG. 1 (a), after coating the polymerizable liquid crystal composition on the base film 100, it is semi-cured by ultraviolet rays or the like to form a semi-cured polymerizable liquid crystal layer 110a, A polymerizable liquid crystal film 10 is manufactured. Under the present circumstances, ultraviolet irradiation may be irradiated from the side (polymerizable liquid crystal layer side) which coated the polymerizable liquid crystal composition, and may be irradiated from the base film 100 side. As shown in FIG. 1B, the semi-cured polymerizable liquid crystal layer 110a is given a surface shape by heating or pressurizing using a mold 120, and becomes a polymerizable liquid crystal layer 110b having a surface shape. Here, the laminated body of the base film 100 and the polymerizable liquid crystal layer 110b having the surface shape is the polymerizable liquid crystal film 11 having the surface shape. Furthermore, the optical film 12 of the present invention can be obtained by subjecting the polymerizable liquid crystal layer 110b of the polymerizable liquid crystal film 11 having a surface shape to main curing to obtain a cured layer 110c. In the case of the main curing, the ultraviolet ray may be irradiated from the polymerizable liquid crystal layer side or from the base film 100 side.

(Polymerizable liquid crystal composition)
Examples of the polymerizable liquid crystal composition used for the production of the optical film of the present invention include a composition containing a cholesteric liquid crystal compound and a composition containing a nematic liquid crystal compound. As the cholesteric liquid crystalline compound, a composition containing a liquid crystalline compound and capable of exhibiting a cholesteric liquid crystal phase when formed into a coating film can be used, and a polymerizable liquid crystalline compound is used for obtaining high thermal stability. . The polymerizable liquid crystal compound is polymerized in a state exhibiting cholesteric regularity to cure the coating film, and a non-liquid crystalline resin layer cured while exhibiting cholesteric regularity (hereinafter simply referred to as “cholesteric resin”). Layer ").

  The cholesteric regularity means that the molecular axes are aligned in a certain direction on one plane, but the direction of the molecular axis is slightly shifted in the next plane that overlaps it, and the angle is further increased in the next plane. It is a structure in which the angles of molecular axes in the planes are shifted (twisted) as they sequentially pass through the overlapping planes as they shift. Thus, the structure in which the direction of the molecular axis is twisted becomes an optically chiral structure.

  The cholesteric resin layer usually has a circularly polarized light separating function. That is, it has a property of transmitting one circularly polarized light of right circularly polarized light and left circularly polarized light and reflecting a part or all of the other circularly polarized light. The reflection in the cholesteric resin layer reflects circularly polarized light while maintaining its chirality. The cholesteric resin layer has this circularly polarized light separating function in the widest possible wavelength band of visible light and has as high a reflectance as possible. And a high degree of freedom in design is preferable.

  The wavelength that exhibits the circularly polarized light separation function depends on the pitch of the helical structure in the cholesteric resin layer. The pitch of the helical structure is the distance in the plane normal direction until the angle of the molecular axis in the helical structure gradually shifts as it advances along the plane and then returns to the original molecular axis direction again. By changing the pitch of the helical structure, the wavelength at which the circularly polarized light separating function is exhibited can be changed.

  The cholesteric resin layer can be obtained by providing a coating film of a cholesteric liquid crystal composition on a suitable base film for forming a resin layer and curing the coating film. However, the present invention is characterized in that a shape is imparted to the surface of the semi-cured layer in the stage before the cholesteric resin layer, that is, in a semi-cured state.

Semi-curing is, for example, when photopolymerizing a polymerizable liquid crystal composition, irradiating it with ultraviolet rays at an irradiation dose such that the polymerization conversion rate of the photopolymerizable liquid crystal compound does not become 100%, and pressing the fingertip with light pressure. Is a state in which no trace of fingerprints remains and does not exhibit adhesiveness. In the case of a photopolymerizable liquid crystal compound, it is semi-cured when the photopolymerizable liquid crystal compound is polymerized by irradiating light having a wavelength of 350 to 400 nm in a range of more than 0 to 400 mJ / cm ² or less. In the semi-cured state, it is softer than the case where the polymerization conversion rate becomes 100%. The surface shape to be imparted varies depending on the application, but embossed, corrugated, a cross-sectional shape such as a triangle or trapezoid, and a concave-convex shape such as a pyramid shape can be considered. The width, depth, and pitch of the concavo-convex shape can be appropriately selected from 1 nm to 1 mm depending on the application.

  As a method for imparting a concavo-convex structure to a semi-cured layer, there is a chemical method in addition to a physical method of pressing with a mold or the like as described above. The conditions for physically imparting unevenness are preferably 0.05 to 80 MPa and 40 to 180 ° C.

  After providing a concavo-convex structure to the semi-cured polymerizable liquid crystal layer, the polymerizable liquid crystal layer is preferably subjected to main curing. For example, when the polymerizable liquid crystal composition is photopolymerized, the main curing means curing so that the polymerization conversion rate of the photopolymerizable liquid crystal compound becomes 100%. By the main curing step, a cholesteric resin layer is formed, and an optical film having an optical function due to the uneven shape can be obtained together with the circularly polarized light separating function. The main curing can be performed after imparting the uneven shape, but the main curing can also be performed by the following method shown in FIG.

(I) The concave and convex shape is imparted by the mold 220, and at the same time, ultraviolet rays are irradiated from the base film 200 and the pressing table 240 side a. At that time, it is preferable that the press table 240 is also transparent.
(Ii) Using transparent glass or resin for the mold 220 itself, the mold 220 is irradiated with ultraviolet rays from the direction 220 of the mold 220 while the polymerizable liquid crystal layer is pressed with the mold 220.
(Iii) In a state where the polymerizable liquid crystal layer is pressed with the mold 220, ultraviolet irradiation is performed from the end c side of the polymerizable liquid crystal layer 210b.
In any of the above cases, heating can be performed simultaneously with the ultraviolet irradiation. In addition, a transparent mold or press table that absorbs less ultraviolet light and can withstand pressure and heating during pressing is suitable. Thus, the optical film provided with the concavo-convex shape in the semi-cured state has an advantage that it is easier to give the shape and has excellent heat resistance than the method of providing the concavo-convex shape in the cured state.

  The intrinsic birefringence value Δn of the cholesteric resin layer to be produced is preferably 0.2 or more, more preferably 0.22 or more. By having such a high Δn value, in the case of an optical film, it is possible to reduce the hue change when observed from an oblique direction while obtaining a high luminance improvement effect. The cholesteric resin layer having such a high Δn value can be formed by using a liquid crystal composition such as a cholesteric liquid crystal composition (X) described later. If a compound having a Δn value of 0.30 or more is used, the absorption edge on the long wavelength side of the ultraviolet absorption spectrum may extend to the visible range. It can be used as long as the performance is not adversely affected.

   Examples of the cholesteric resin layer having a high visible light average reflectance that can be preferably used in the present invention include (i) a cholesteric resin layer in which the pitch of the helical structure is changed stepwise, and (ii) a pitch of the helical structure. Examples thereof include a cholesteric resin layer in which the size of is continuously changed.

(I) A cholesteric resin layer in which the pitch of the helical structure is changed stepwise can be obtained by laminating a plurality of cholesteric resin layers having different helical structure pitches. Lamination can be performed by previously forming a plurality of cholesteric resin layers having different helical structure pitches, and then fixing each layer with an adhesive or an adhesive. Or it can also carry out by forming another cholesteric resin layer in order after forming a cholesteric resin layer.

(Ii) The cholesteric resin layer in which the pitch of the helical structure is continuously changed is not particularly limited by the manufacturing method, but a preferable example of the manufacturing method of such a cholesteric resin layer is to form a cholesteric resin layer. A cholesteric liquid crystal composition containing a polymerizable liquid crystalline compound for coating is preferably applied on another layer such as an alignment film to obtain a layer of the liquid crystal composition, and then one or more times of light irradiation and / or application. A method of curing the layer in a state where the pitch of the helical structure is continuously changed by the heat treatment is mentioned. Such an operation is an operation for extending the reflection band of the cholesteric resin layer, and is therefore called a broadening process. Preferable embodiments of the cholesteric liquid crystal composition subjected to such a broadening treatment include cholesteric liquid crystal composition (X) described in detail below.

The cholesteric resin layer in which the pitch of the helical structure of (ii) is continuously changed may be a single cholesteric resin layer used in the present invention, or a plurality of layers may be stacked and used in the present invention. A cholesteric resin layer may be used. For example, a combination of a cholesteric resin layer that exhibits a circularly polarized light separating function in a part of the visible light wavelength region and a cholesteric resin layer that exhibits a circularly polarized light separating function in another region, It is possible to use a cholesteric resin layer that exhibits a circularly polarized light separating function in a wide area.

The cholesteric resin layer may be a resin layer consisting of only one layer, or two or more layers such as the above (i) cholesteric resin layer, the above (ii) cholesteric resin layer, or a laminate of any one or both of them. The resin layer which consists of these layers may be sufficient.
The number of layers constituting the cholesteric resin layer is preferably 1 to 100 layers, and more preferably 1 to 20 layers, from the viewpoint of ease of production. As a result of the broadening treatment described above, when a cholesteric resin layer having high visible light average reflectance is obtained with only one layer, an optical film of a preferred embodiment can be obtained even by using only one layer. . Even in that case, when forming at least the outermost layer, it is necessary to provide a concavo-convex shape in a semi-cured state as described above. Is also possible.

The cholesteric liquid crystal composition (X) contains a compound represented by the following general formula (1) and a specific rod-like liquid crystal compound. Each of these components will be described in turn.
R ¹ -A ¹ -BA ² -R ² (1)

In General Formula (1), R ¹ and R ² are each independently a linear or branched alkyl group having 1 to 20 carbon atoms, or a linear or branched chain having 1 to 20 carbon atoms. And a group selected from the group consisting of a hydrogen atom, a halogen atom, a hydroxyl group, a carboxyl group, a (meth) acryl group, an epoxy group, a mercapto group, an isocyanate group, an amino group, and a cyano group. Here, (meth) acryl means acryl and methacryl.

  The alkyl group and alkylene oxide group may be unsubstituted or substituted with one or more halogen atoms. The halogen atom, hydroxyl group, carboxyl group, (meth) acryl group, epoxy group, mercapto group, isocyanate group, amino group, and cyano group are bonded to an alkyl group having 1 to 2 carbon atoms or an alkylene oxide group. May be.

Preferable examples of R ¹ and R ² include a halogen atom, a hydroxyl group, a carboxyl group, a (meth) acryl group, an epoxy group, a mercapto group, an isocyanate group, an amino group, and a cyano group.

Moreover, it is preferable that at least one of R ¹ and R ² is a reactive group. By having a reactive group as R ¹ and / or R ² , the compound represented by the general formula (1) is fixed in the liquid crystal layer at the time of curing, and a stronger film can be formed. Here, examples of the reactive group include a carboxyl group, a (meth) acryl group, an epoxy group, a mercapto group, an isocyanate group, and an amino group.

In the general formula (1), A ¹ and A ² are each independently 1,4-phenylene group, 1,4-cyclohexylene group, 1,4-cyclohexenyl group, 4,4′-biphenylene group, 4, It represents a group selected from the group consisting of a 4′-bicyclohexylene group and a 2,6-naphthylene group. The 1,4-phenylene group, 1,4-cyclohexylene group, 1,4-cyclohexenyl group, 4,4′-biphenylene group, 4,4′-bicyclohexylene group, and 2,6-naphthylene group are , It may be unsubstituted or substituted with one or more halogen atoms, hydroxyl groups, carboxyl groups, cyano groups, amino groups, alkyl groups having 1 to 10 carbon atoms, or halogenated alkyl groups. In each of A ¹ and A ² , when two or more substituents are present, they may be the same or different.

Particularly preferred as A ¹ and A ² are groups selected from the group consisting of 1,4-phenylene group, 4,4′-biphenylene group, and 2,6-naphthylene group. These aromatic ring skeletons are relatively rigid as compared with the alicyclic skeletons, have high affinity with the mesogens of rod-like liquid crystalline compounds described later, and have higher alignment uniformity.

In the general formula (1), B represents a single bond, —O—, —S—, —S—S—, —CO—, —CS—, —OCO—, —CH ₂ —, —OCH ₂ —, —CH. = N-N = CH -, - NHCO -, - OCOO -, - CH 2 COO-, and is selected from the group consisting of _-CH 2 OCO-.

  Particularly preferable examples of B include a single bond, —OCO—, and —CH═N—N═CH—.

As for the compound of General formula (1), it is preferable that at least 1 type has liquid crystallinity, and it is preferable to have chirality. The cholesteric liquid crystal composition (X) preferably contains a mixture of a plurality of optical isomers as the compound of the general formula (1). For example, a mixture of plural kinds of enantiomers and / or diastereomers can be contained.
At least one of the compounds of the general formula (1) preferably has a melting point in the range of 50 ° C to 150 ° C.

  When the compound of the general formula (1) has liquid crystallinity, a high Δn is preferable. By containing a high Δn liquid crystal, Δn as the cholesteric liquid crystal composition (X) can be improved, and a cholesteric resin layer having a wide selective reflection band can be produced. At least one Δn of the compound of the general formula (1) is preferably 0.18 or more, more preferably 0.22 or more.

  Specific examples of particularly preferred compounds of the general formula (1) include the following compounds (A1) to (A9):

  In the compound (A3), “*” represents a chiral center.

The cholesteric liquid crystal composition (X) contains a rod-like liquid crystal compound having Δn of 0.18 or more and having at least two or more reactive groups in one molecule.
Examples of the rod-like liquid crystalline compound include compounds represented by the formula (2).
R ³ -C ³ -D ³ -C ⁵ -M C ⁶ -D ⁴ -C ⁴ -R ⁴ Formula (2)
(Wherein R ³ and R ⁴ are reactive groups, each independently (meth) acrylic group, (thio) epoxy group, oxetane group, thietanyl group, aziridinyl group, pyrrole group, vinyl group, allyl group, D ³ and D ⁴ each represents a group selected from the group consisting of a fumarate group, a cinnamoyl group, an oxazoline group, a mercapto group, an iso (thio) cyanate group, an amino group, a hydroxyl group, a carboxyl group, and an alkoxysilyl group. A group selected from the group consisting of a bond, a linear or branched alkyl group having 1 to 20 carbon atoms, and a linear or branched alkylene oxide group having 1 to 20 carbon atoms; C ^{3 to} C ⁶ are a single bond, —O—, —S—, —S—S—, —CO—, —CS—, —OCO—, —CH ₂ —, —OCH ₂ —, —CH═. N-N = CH _{, -NHCO -, - OCOO -,} - CH 2 COO-, and .M represents a group selected from the group consisting of _-CH 2 OCO- represents a mesogenic group, specifically, an unsubstituted or substituted group Azomethines, azoxys, phenyls, biphenyls, terphenyls, naphthalenes, anthracenes, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines , 2-4 skeletons selected from the group of alkoxy-substituted phenylpyrimidines, phenyldioxanes, tolanes, alkenylcyclohexylbenzonitriles, -O-, -S-, -SS-, -CO _{-, - CS -, - OCO} -, - CH 2 -, - OCH 2 -, - CH = N-N = CH -, - NHC _{-, - OCOO -, - CH} 2 COO-, and is formed are joined by a linking group of _-CH 2 OCO-, etc.).
Examples of the substituent that the mesogenic group M may have include a halogen atom, an optionally substituted alkyl group having 1 to 10 carbon atoms, a cyano group, a nitro group, —O—R ⁵ , —O—C. (═O) —R ⁵ , —C (═O) —O—R ⁵ , —O—C (═O) —O—R ⁵ , —NR ⁵ —C (═O) —R ⁵ , —C (= O) represents an ^-NR 5 ^{R 7} or ^{-O-C (= O) -NR} 5 R 7,. Wherein, ^{R 5} and ^{R 7} represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, when it is alkyl group, and the alkyl group, -O -, - S -, - O-C (= O) —, —C (═O) —O—, —O—C (═O) —O—, —NR ⁶ —C (═O) —, —C (═O) —NR ⁶ —, —NR ^6- or -C (= O)-may be present (except when two or more of -O- and -S- are present adjacent to each other). Here, R ⁶ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. Examples of the substituent in the “optionally substituted alkyl group having 1 to 10 carbon atoms” include a halogen atom, a hydroxyl group, a carboxyl group, a cyano group, an amino group, and an alkoxy group having 1 to 6 carbon atoms. Group, alkoxyalkoxy group having 2 to 8 carbon atoms, alkoxyalkoxyalkoxy group having 3 to 15 carbon atoms, alkoxycarbonyl group having 2 to 7 carbon atoms, alkylcarbonyloxy having 2 to 7 carbon atoms Group, an alkoxycarbonyloxy group having 2 to 7 carbon atoms, and the like.
In the present invention, the rod-like liquid crystalline compound preferably has an asymmetric structure. Here, the asymmetric structure is a structure in which R ³ -C ³ -D ³ -C ⁵ -and -C ⁶ -D ⁴ -C ⁴ -R ⁴ are different in the general formula (2) with the mesogenic group M as the center. Say. By using a rod-like liquid crystal compound having an asymmetric structure, alignment uniformity can be further improved.

  In the present invention, the rod-like liquid crystalline compound has a Δn value of preferably 0.18 or more, more preferably 0.22 or more. When a compound having an Δn value of 0.30 or more is used, the absorption edge on the long wavelength side of the ultraviolet absorption spectrum may extend to the visible range, but desired optical performance even when the absorption edge of the spectrum extends to the visible range. It can be used as long as it does not adversely affect By having such a high Δn value, a cholesteric resin layer having high optical performance (for example, selective reflection performance of circularly polarized light) can be provided.

  In the present invention, the rod-like liquid crystalline compound may have at least two reactive groups in one molecule. Specific examples of the reactive group include an epoxy group, a thioepoxy group, an oxetane group, a thietanyl group, an aziridinyl group, a pyrrole group, a fumarate group, a cinnamoyl group, an isocyanate group, an isothiocyanate group, an amino group, a hydroxyl group, and a carboxyl group. , Alkoxysilyl groups, oxazoline groups, mercapto groups, vinyl groups, allyl groups, methacryl groups, and acrylic groups. By having these reactive groups, a stable cured product can be obtained when the cholesteric liquid crystal composition is cured. When a compound having one or less reactive group in one molecule is used, when the cholesteric liquid crystal composition is cured, a crosslinked cured product cannot be obtained, so that there is a possibility that a film strength that can withstand practical use cannot be obtained. . Even when a cross-linking agent described later is used, the film strength may be insufficient and practical use may be difficult. The film strength that can be practically used is HB or more, preferably H or more, in pencil hardness (JIS K5400). If the film strength is lower than HB, the film is easily scratched and lacks handling properties. The upper limit of preferable pencil hardness is not particularly limited as long as it does not adversely affect the optical performance and durability test.

  Preferable specific examples of the rod-like liquid crystalline compound include the following compounds (B1) to (B9), but the rod-like liquid crystalline compound in the present invention is not limited to the following compounds.

  In the cholesteric liquid crystal composition (X), the weight ratio of (total weight of the compound of the general formula (1)) / (total weight of the rod-like liquid crystal compound) is 0.05 to 1, preferably 0.1 to 0. .65, more preferably 0.15 to 0.45. When the weight ratio is less than 0.05, the alignment uniformity may be insufficient. On the other hand, when the weight ratio is more than 1, the alignment uniformity decreases, the stability of the liquid crystal phase decreases, and the liquid crystal composition As a result, the desired optical performance (for example, the property of selectively reflecting circularly polarized light) may not be obtained. The total weight indicates the weight when one kind is used and the total weight when one or more kinds are used.

  In the cholesteric liquid crystal composition (X), the compound of the general formula (1) preferably has a molecular weight of less than 600, and the rod-like liquid crystal compound has a molecular weight of 600 or more. When the molecular weight of the compound of the general formula (1) is less than 600, the rod-like liquid crystal compound having a molecular weight larger than that can enter the gap, and the alignment uniformity can be improved.

In the present invention, the cholesteric liquid crystal composition such as the cholesteric liquid crystal composition (X) can optionally contain a cross-linking agent in order to improve the film strength and durability after curing. As the cross-linking agent, it reacts simultaneously when the liquid crystal layer coated with the liquid crystal composition is cured, or heat treatment is performed after curing to accelerate the reaction, or the reaction proceeds spontaneously by moisture to increase the cross-linking density of the liquid crystal layer. Those that can be enhanced and that do not deteriorate the alignment uniformity can be appropriately selected and used, and those that are cured by ultraviolet rays, heat, moisture, etc. can be suitably used. Specific examples of the crosslinking agent include, for example, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 2- (2-vinyl Polyfunctional acrylate compounds such as loxyethoxy) ethyl acrylate; epoxy compounds such as glycidyl (meth) acrylate, ethylene glycol diglycidyl ether, glycerin triglycidyl ether, pentaerythritol tetraglycidyl ether; 2,2-bishydroxymethylbutanol-tris [ 3- (1-aziridinyl) propionate], 4,4-bis (ethyleneiminocarbonylamino) diphenylmethane, trimethylolpropane-tri-β-aziri Aziridine compounds such as nylpropionate; Isocyanurate type isocyanates derived from hexamethylene diisocyanate, hexamethylene diisocyanate, isocyanurate type isocyanates, biuret type isocyanates, adduct type isocyanates, etc .; Polyoxazoline compounds having an oxazoline group in the side chain; Methoxysilane, N- (2-aminoethyl) 3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3- (meth) acryloxypropyltrimethoxysilane, N And alkoxysilane compounds such as-(1,3-dimethylbutylidene) -3- (triethoxysilyl) -1-propanamine; Moreover, a well-known catalyst can be used according to the reactivity of this crosslinking agent, and productivity can be improved in addition to an improvement in film strength and durability.
The blending ratio of the crosslinking agent is preferably 0.1 to 15% by weight in a cured film obtained by curing the cholesteric liquid crystal composition. When the blending ratio of the crosslinking agent is less than 0.1% by weight, the effect of improving the crosslinking density cannot be obtained. Conversely, when the blending ratio is more than 15% by weight, the stability of the liquid crystal layer is lowered, which is not preferable.

In the present invention, the cholesteric liquid crystal composition can optionally contain a photoinitiator. As the photoinitiator, known compounds that generate radicals or acids by ultraviolet rays or visible rays can be used. Specifically, benzoin, benzylmethyl ketal, benzophenone, biacetyl, acetophenone, Michler's ketone, benzyl, benzylisobutyl ether, tetramethylthiuram mono (di) sulfide, 2,2-azobisisobutyronitrile, 2,2-azobis -2,4-dimethylvaleronitrile, benzoyl peroxide, di-tert-butyl peroxide, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1- (4 -Isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-diethylthioxanthone, methylbenzoyl formate, 2,2-dieto Xyacetophenone, β-ionone, β-bromostyrene, diazoaminobenzene, α-amylcinnackaldehyde, p-dimethylaminoacetophenone, p-dimethylaminopropiophenone, 2-chlorobenzophenone, pp′-dichlorobenzophenone, pp ′ -Bisdiethylaminobenzophenone, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-propyl ether, benzoin n-butyl ether, diphenyl sulfide, bis (2,6-methoxybenzoyl) -2,4,4-trimethyl-pentylphosphine oxide, 2,4,6-trimethylbenzoyldiphenyl-phosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, 2-methyl-1 4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one, anthracenebenzophenone, α-chloroanthraquinone , Diphenyl disulfide, hexachlorobutadiene, pentachlorobutadiene, octachlorobutene, 1-chloromethylnaphthalene, 1,2-octanedione, 1- [4- (phenylthio) -2- (o-benzoyloxime)] and 1- Carbazole oxime compounds such as [9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl] ethanone 1- (o-acetyloxime), (4-methylphenyl) [4- (2-methyl Propyl) phenyl] iodonium hexafluorophosphate, 3- Chill -2 butynyl tetramethyl hexafluoroantimonate, diphenyl - (p-phenylthiophenyl) sulfonium hexafluoroantimonate, and the like. Also, two or more kinds of compounds can be mixed depending on the desired properties, and if necessary, a known photosensitizer or a tertiary amine compound as a polymerization accelerator is added to control curability. You can also.
The blending ratio of the photoinitiator is preferably 0.03 to 7% by weight in the cholesteric liquid crystal composition. When the blending amount of the photoinitiator is less than 0.03% by weight, the degree of polymerization is lowered and the film strength may be lowered. On the other hand, if it is more than 7% by weight, the orientation of the liquid crystal material is inhibited and the liquid crystal phase may become unstable, which is not preferable.

  In the present invention, the cholesteric liquid crystal composition can optionally contain a surfactant. As the surfactant, those not inhibiting the orientation can be appropriately selected and used. As the surfactant, specifically, a nonionic surfactant containing siloxane or fluorinated alkyl group in the hydrophobic group portion can be preferably used, and an oligomer having two or more hydrophobic group portions in one molecule. Is particularly preferred. These surfactants are PF-151N, PF-636, PF-6320, PF-656, PF-6520, PF-3320, PF-651, PF-652 from PolyFox, OMNOVA, FTX- from Neos 209F, FTX-208G, FTX-204D, Seimi Chemical's Surflon KH-40, and the like can be used. The blending ratio of the surfactant is preferably 0.05% by weight to 3% by weight in the cured film obtained by curing the cholesteric liquid crystal composition. When the blending ratio of the surfactant is less than 0.05% by weight, the orientation regulating force at the air interface is lowered and an orientation defect may occur, which is not preferable. On the other hand, when the amount is more than 3% by weight, it is not preferable because an excessive surfactant may enter between liquid crystal molecules and lower the alignment uniformity.

  In the present invention, the cholesteric liquid crystal composition can optionally contain a chiral agent. Specific examples of the chiral agent include JP-A-2005-289881, JP-A-2004-115414, JP-A-2003-66214, JP-A-2003-313187, JP-A-2003-342219, JP-A-2000-290315, JP-A-6-072962, U.S. Pat. No. 6,468,444, WO98 / 00428, JP-A-2007-176870, etc. can be used as appropriate. For example, it can be obtained as LC756 of BASF Corporation Paliocolor.

  The chiral agent can be added within a range that does not deteriorate the desired optical performance. The content ratio of the chiral agent is usually 1 to 60% by weight in the cholesteric liquid crystal composition.

  In the present invention, the cholesteric liquid crystal composition can further contain other optional components as necessary. Examples of the other optional components include a solvent, a polymerization inhibitor for improving pot life, an antioxidant for improving durability, an ultraviolet absorber, and a light stabilizer. These optional components can be added as long as the desired optical performance is not deteriorated.

  The production method of the cholesteric liquid crystal composition used in the present invention is not particularly limited, and can be produced by mixing the above-described components.

  An alignment film is provided on the surface of the base film made of a transparent resin, etc., if necessary, and further subjected to treatment such as corona discharge treatment rubbing treatment, and a coating film of a cholesteric liquid crystal composition is applied on this surface. A semi-cured layer and a cholesteric resin layer can be obtained by providing and further performing an orientation treatment and / or a curing treatment as necessary. The application can be carried out by a known method such as an extrusion coating method, a direct gravure coating method, a reverse gravure coating method, a die coating method, or a bar coating method.

  The alignment treatment can be performed, for example, by heating the coating film at 50 to 150 ° C. for 0.5 to 10 minutes. By performing the alignment treatment, the cholesteric liquid crystal composition in the coating film can be aligned well.

  In the case of photocuring, the curing treatment can be performed by a combination of one or more light irradiations and a heating treatment. Specifically, the heating conditions are, for example, a temperature of 40 to 200 ° C., preferably 50 to 200 ° C., more preferably 50 to 140 ° C., and a time of 1 second to 3 minutes, preferably 5 to 120 seconds. it can. The light used for light irradiation in the present invention includes not only visible light but also ultraviolet rays and other electromagnetic waves. Specifically, the light irradiation can be performed by, for example, irradiating light having a wavelength of 200 to 500 nm for 0.01 second to 3 minutes.

Here, a circle having a wide reflection band, in which the pitch of the helical structure is continuously changed greatly by repeating weak UV irradiation of 0.01 to 50 mJ / cm ² and heating a plurality of times alternately. A polarization separation element can be obtained. After extending the reflection band by the above-mentioned weak UV irradiation, etc., UV irradiation of 0.01 mJ / cm ² or more and 400 mJ / cm ² or less is performed (after semi-curing) to give a surface shape, and then 400 mJ It is possible to form a cholesteric resin layer by completely polymerizing the liquid crystalline compound by irradiating with relatively strong ultraviolet rays exceeding / cm ² and 10,000 mJ / cm ² or less. The expansion of the reflection band and the irradiation with strong ultraviolet rays may be performed in the air, or a part or all of the process may be performed in an atmosphere in which the oxygen concentration is controlled (for example, in a nitrogen atmosphere). .

  In the present invention, the process of applying and curing the cholesteric liquid crystal composition on other layers such as an alignment film is not limited to one time, and the application and curing are repeated a plurality of times to form two or more cholesteric resin layers, Only the outermost layer can be semi-cured and imparted with a surface shape. However, by using a liquid crystal composition such as the cholesteric liquid crystal composition (X), a well-oriented rod-like liquid crystal compound having a Δn of 0.18 or more even when the cholesteric liquid crystal composition is applied and cured only once. And a cholesteric resin layer having a thickness of 5 μm or more can be easily formed.

  In the present invention, the thickness of the cholesteric resin layer is preferably 0.1 μm or more and more preferably 1 μm or more for obtaining sufficient reflectance. Moreover, in order to obtain the transparency of the film, the thickness is preferably 20 μm or less, and more preferably 10 μm or less. The thickness of the cholesteric resin layer is the sum of the thickness of each layer when the cholesteric resin layer of the display medium of the present invention is two or more layers, and the thickness of the cholesteric resin layer when the cholesteric resin layer is one layer. Thickness is indicated.

(Base film)
The base film that can be used for forming the polymerizable liquid crystal layer is not particularly limited, and a base film having a thickness of 1 mm and a total light transmittance of 80% or more can be used. Specifically, alicyclic olefin polymers, chain olefin polymers such as polyethylene and polypropylene, triacetyl cellulose, polyvinyl alcohol, polyimide, polyarylate, polyester, polycarbonate, polysulfone, polyethersulfone, modified acrylic polymer, epoxy resin, Examples thereof include a single layer or laminated film made of a synthetic resin such as polystyrene or acrylic resin. Among these, an alicyclic olefin polymer or a chain olefin polymer is preferable, and an alicyclic olefin polymer is particularly preferable from the viewpoint of transparency, low hygroscopicity, dimensional stability, lightness, and the like. In particular, when a resin film capable of transmitting ultraviolet rays is used, it is preferable because the steps of semi-curing and main curing can be performed by irradiating ultraviolet rays from the base film side.

  When an alignment film is used for forming the cholesteric resin layer, the alignment film is subjected to a corona discharge treatment, if necessary, on the surface of the substrate, and then a solution in which the alignment film material is dissolved in water or a solvent. Can be formed by applying and drying using a known method such as reverse gravure coating, direct gravure coating, die coating, and bar coating, and then subjecting the dried coating film to rubbing treatment. As the material for the alignment film, cellulose, silane coupling agent, polyimide, polyamide, polyvinyl alcohol, epoxy acrylate, silanol oligomer, polyacrylonitrile, phenol resin, polyoxazole, cyclized polyisoprene, etc. can be used. Polyamide is particularly preferred.

Examples of the modified polyamide include those obtained by modifying an aromatic polyamide or an aliphatic polyamide, and those obtained by modifying an aliphatic polyamide are preferred. Specifically, for example, modified to nylon-6, nylon-66, nylon-12, ternary to quaternary copolymer nylon, fatty acid polyamide, or fatty acid block copolymer (for example, polyether ester amide, polyester amide). Can be mentioned. Examples of the modification include terminal amino modification, carboxyl modification, hydroxyl modification and the like, and modification in which a part of the amide group is alkylaminated or N-alkoxyalkylated. Examples of the N-alkoxyalkylated modified polyamide include N-methoxymethylated part of the amide group of a copolymer nylon such as nylon-6, nylon-66, or nylon-12. The weight average molecular weight of the modified polyamide is preferably 5,000 to 500,000, more preferably 10,000 to 200,000.
The thickness of the alignment film may be any film thickness that provides the desired alignment uniformity of the liquid crystal layer, and is preferably 0.001 to 5 μm, and more preferably 0.01 to 2 μm.

  The twist direction of the cholesteric resin layer can be appropriately selected depending on the type (structure) of the chiral agent to be used. When the twist is set to the right direction, a chiral agent that imparts dextrorotation is used, and when the twist direction is set to the left direction, it can be realized by using a chiral agent that imparts levorotation.

(Any layer)
The polymerizable liquid crystal film or optical film of the present invention can be provided with any other layer as required. Specific examples of such an optional layer include a protective layer, an easy-adhesion layer, an easy-slip layer, a hard coat layer, an antistatic layer, an abrasion-resistant layer, an antireflection layer, a color correction layer, an ultraviolet absorption layer, and a printing. Functional layers such as a layer, a metal layer, a transparent conductive layer, a gas barrier layer, a hologram layer, a release layer, an adhesive layer, and an emboss layer can be provided.

[Second Embodiment]
In the second embodiment of the production method of the present invention, a polymerizable liquid crystal composition is applied on a base film, a polymerizable liquid crystal layer is formed, semi-cured by light or heat, and semi-cured. After transferring the liquid crystal layer to the transfer film, the polymerizable liquid crystal layer can be given a surface shape by a physical or chemical method. Further, it is preferable that the step of fully curing the polymerizable liquid crystal layer imparted with the surface shape is the same as in the first embodiment.

  Conditions such as a base film, a polymerizable liquid crystal composition, and semi-curing used in this embodiment are the same as those in the first embodiment. By transferring the semi-cured polymerizable liquid crystal layer formed on the base film onto the transfer base film, the polymerizable liquid crystal layer can be provided on any transfer base film. Such transfer can be performed by pasting the substrate film for transfer and the polymerizable liquid crystal film on the polymerizable liquid crystal layer side through an adhesive layer and peeling the substrate film. Prior to transfer, the adhesive layer can be provided in advance on either one or both of the facing surfaces of the polymerizable liquid crystal layer and the transfer film to be transferred. When the polymerizable liquid crystal layer is formed on the alignment film on the base film, only the polymerizable liquid crystal layer may be transferred, or both the polymerizable liquid crystal layer and the alignment film may be transferred. From the viewpoint of easy peeling and prevention of occurrence of poor alignment of the polymerizable liquid crystal layer, it is preferable to transfer both the polymerizable liquid crystal layer and the alignment film.

  The second embodiment will be described more specifically with reference to the drawings. Similar to the first embodiment, as shown in FIG. 2A, the polymerizable liquid crystal composition is applied on the base film 300, and then semi-cured by ultraviolet rays or the like to be semi-cured. A liquid crystal layer 310a is formed, and the polymerizable liquid crystal film 30 is manufactured. Thereafter, the transfer base film 340 is bonded to the polymerizable liquid crystal layer side surface of the polymerizable liquid crystal film 30 through the adhesive layer 330 (FIG. 2B). Thereafter, the base film is peeled off (FIG. 2 (c)), and a surface shape is imparted to the side of the polymerizable liquid crystal layer 310a from which the base film has been peeled by a mold 320 or the like, and semi-cured polymerization having the surface shape. Liquid crystal film 31 is obtained (FIG. 2D). Furthermore, the optical film 32 of the present invention can also be obtained by subjecting the polymerizable liquid crystal layer 310b of the polymerizable liquid crystal film 31 having a surface shape to main curing to form a cured layer 310c.

(Transfer base film)
As the transfer base film, the same base film as that used in the first embodiment can be used. That is, a film having a thickness of 1 mm and a total light transmittance of 80% or more can be used. Specifically, alicyclic olefin polymers, chain olefin polymers such as polyethylene and polypropylene, triacetyl cellulose, polyvinyl alcohol, polyimide, polyarylate, polyester, polycarbonate, polysulfone, polyethersulfone, modified acrylic polymer, epoxy resin, Examples thereof include a single layer or laminated film made of a synthetic resin such as polystyrene or acrylic resin. Among these, an alicyclic olefin polymer or a chain olefin polymer is preferable, and an alicyclic olefin polymer is particularly preferable from the viewpoint of transparency, low hygroscopicity, dimensional stability, lightness, and the like. In particular, when a resin film capable of transmitting ultraviolet rays is used, it is preferable because the steps of semi-curing and main curing can be performed by irradiating ultraviolet rays from the base film side.

(Adhesive layer)
In the step of transferring the semi-cured polymerizable liquid crystal layer to the transfer base film, it is preferable to have an adhesive layer at the interface between the polymerizable liquid crystal layer and the transfer base film. The pressure-sensitive adhesive layer can be a layer formed by laminating a pressure-sensitive adhesive composition containing a polymer that expresses pressure-sensitive properties (hereinafter sometimes simply referred to as “main polymer”) and curing it as necessary. .

  Examples of the main polymer include acrylic, urethane, polyester, polyamide, polyvinyl ether, polyvinyl alcohol, polyvinyl acetal, polyvinyl formal, hydroxyethyl cellulose, hydroxypropyl cellulose, ethylene-vinyl acetate, ethylene-acrylic ester, ethylene -Synthetic rubber type, such as vinyl chloride type, styrene-butadiene-styrene, epoxy type, and silicone type polymer can be used. In particular, acrylic, urethane, and ethylene-vinyl acetate are preferably used.

  Acrylic polymers include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, hexyl (meth) acrylate, (meth ) (Meth) acrylic acid alkyl esters such as octyl acrylate, nonyl (meth) acrylate, decyl (meth) acrylate; unsaturated such as (meth) acrylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid Carboxylic acid; Hydroxyl group-containing vinyl monomer such as (meth) acrylic acid-2-hydroxyethyl, monoester of (meth) acrylic acid and polyethylene glycidicol or polypropylene glycol; Epoxy such as glycidyl (meth) acrylate Group-containing vinyl monomer; methoxyethyl (meth) acrylate, ( T) Ethoxyethyl acrylate, propoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, ethoxypropyl (meth) acrylate, alkoxyalkyl (meth) acrylate; (meth) acrylamide, methylol (meth) acrylamide Amide group-containing vinyl monomers such as methoxyethyl (meth) acrylamide; silicon-containing vinyl monomers such as methacryloxypropylmethoxysilane; aziridine group-containing vinyl monomers such as (meth) acryloylaziridine; (meth) acrylic Aromatic group-containing vinyl monomers such as phenyl acid, benzyl (meth) acrylate, styrene, methylstyrene; alicyclic alcohols such as cyclohexyl (meth) acrylate and isobornyl (meth) acrylate and (meth) acrylic acid Esters with 2 (meth) acryloyl groups such as ethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, etc. Monomers having at least one monomer; and other single polymers or copolymers of plural monomers such as vinyl acetate, vinyl chloride, macromonomer, and divinylbenzene. In addition, (meth) acrylic acid means both acrylic acid and methacrylic acid, and (meth) acrylate means both acrylate and methacrylate.

  Examples of the urethane polymer include a reaction product of a general polyol and an isocyanate compound.

  As the polyol, a polyether polyol having a repeating structure of an alkylene oxide chain such as a methylene oxide chain, an ethylene oxide chain, an ethylene oxide chain, a propylene oxide chain, and a butylene oxide chain, or two or more kinds; terephthalic acid, adipic acid, Acid compounds such as adipic acid, sebacic acid, phthalic anhydride, isophthalic acid, trimet acid and ethylene glycol, propylene glycol, diethylene glycol, butylene glycol, 1,6-hexane glycol, 3-methyl-1,5-pentanediol, 3, Glycos such as 3'-dimethylol heptane, polyoxyethylene glycol, polyoxypropylene glycol, 1,4-butanediol, neopentyl glycol, butylethylpentanediol Polyester polyol obtained by esterification reaction with the above component; Polyester polyol obtained by reaction of the above acid compound with polyol such as glycerin, trimethylolpropane, pentaerythritol; polycaprolactone, poly (β-methyl-γ-valerolactone) And polyester polyols obtained by ring-opening polymerization of lactones such as polyvalerolactone.

  Examples of the isocyanate compound include 1,3-phenylene diisocyanate, 4,4′-diphenyl diisocyanate, 1,4-phenylene diisocyanate, 4,4′-diphenylenemethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate. Aromatic polyisocyanates such as diisocyanate, 4,4′-toluidine diisocyanate, 4,4′-diphenyl ether diisocyanate; trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 2,3-butylene diisocyanate, 1, Aliphatic polymers such as 3-butylene diisocyanate, dodecane methylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate Cyanate; ω, ω′-diisocyanate-1,3-dimethylbenzene, ω, ω′-diisocyanate-1,4-dimethylbenzene, ω, ω′-diisocyanate-1,3-diethylbenzene, 1,4-tetramethylxylyl Aromatic aliphatic polyisocyanates such as diisocyanate and 1,3-tetramethylxylylene diisocyanate; 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate methyl -2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 4,4'-methylenebis (cyclohexyl isocyanate), 1,4'-bis (isocyanatomethyl) cyclohexane. Such as aromatic polyisocyanates and the like.

  Examples of the ethylene-vinyl acetate copolymer include an ethylene-vinyl acetate copolymer and an ethylene-vinyl acetate-carboxylic acid copolymer, preferably those having a vinyl acetate copolymerization rate of 10-46% by weight. Can be mentioned.

  The molecular weight range of the main polymer is preferably 10,000 to 1,000,000, and more preferably 50,000 to 500,000 in terms of weight average molecular weight. If the weight average molecular weight is lower than 10,000, it is not preferable because whitening of the adhesive layer is likely to occur. Further, if the weight average molecular weight is larger than 1,000,000, it is not preferable because gelation easily occurs and the viscosity of the adhesive layer solution is high and difficult to handle.

The pressure-sensitive adhesive composition may further contain an acetophenone-containing compound in addition to the main polymer. These compounds may contain 0.5 to 10 parts by weight with respect to 100 parts by weight of the main polymer. preferable. The acetophenone-containing compound is a compound in which one or more hydrogen atoms of acetophenone and acetophenone are substituted with an arbitrary group. Specifically, for example, the —CH ₃ group of acetophenone is substituted with an alicyclic compound or a derivative thereof. Compound (1-hydroxycyclohexyl-phenyl ketone, etc.) and a benzoin ether-containing compound (an ether having a structure in which the hydrogen atom of the —OH group of benzoin is substituted with another organic group, and 1 of the hydrogen atoms of the ether) Examples thereof include compounds in which the above is substituted with an arbitrary group.

Specific examples of the acetophenone-containing compound include acetophenone, methoxyacetophenone, 2,2-diethoxyacetophenone, p-dimethylaminoacetophenone, p-dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone (IRG651 Ciba Specialty) Chemicals Co., Ltd.), α-hydroxy-α, α′-dimethylacetophenone (DAROCURE 1173 manufactured by Ciba Specialty Chemicals Co., Ltd.), 2-hydroxy-2-cyclohexylacetophenone (IRG184 manufactured by Ciba Specialty Chemicals Co., Ltd.), 2- Methyl-1 [4- (methylthio) phenyl] -2-morpholinopropan-1-one (IRG907 manufactured by Ciba Specialty Chemicals), 1- [4- (2-hydroxyeth C) -Phenyl] -2-hydroxy-2-methyl-1-propan-1-one (IRG2959 Ciba Specialty Chemicals), 2-benzyl-2-dimethylamino-1- (4-morpholino) Phenyl) -butanone-1-one (IRG369 manufactured by Ciba Specialty Chemicals Co., Ltd.).
Examples of the benzoin ether-containing compound include benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl butyl ether.
By containing these acetophenone-containing compounds, the performance as an adhesive layer can be improved.

  According to the kind of main polymer, another compounding agent can be further mix | blended with the said adhesive composition. Examples of other compounding agents include diffusing agents, tackifiers, crosslinking agents or curing agents, antioxidants, antifoaming agents, and stabilizers.

  The tackifier imparts adhesive force to the main polymer that is soft and has a solid surface that is easily wetted. Such tackifiers include rosin and rosin derivatives, polyterpene resins, terpene phenol resins, coumarone-indene resins, petroleum resins, hydrogenated petroleum resins and the like. Among these, petroleum resins, hydrogenated petroleum resins, and terpene phenol resins are preferable because they are excellent in transparency and compatibility with the main polymer. The compounding amount of the tackifier is preferably 2 to 50 parts by weight, more preferably 5 to 20 parts by weight with respect to 100 parts by weight of the main polymer. If the addition amount of the tackifier is less than 2 parts by weight, the effect of the tackifier is not expressed. Conversely, if the addition amount exceeds 50 parts by weight, the adhesive force is reduced due to a decrease in the cohesive force of the adhesive. Tend to be.

  Examples of the crosslinking agent or curing agent include trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and 2- (2-vinyloxy). Polyfunctional acrylate compounds such as ethoxy) ethyl acrylate; polyfunctional isocyanate crosslinking agents such as tolylene diisocyanate, hexamethylene diisocyanate, tetramethylene diisocyanate, trimethylolpropane tolylene diisocyanate, diphenylmethane triisocyanate; ethylene glycol glycidyl ether, polyethylene Glycol diglycidyl ether, diglycidyl ether, trimethylolpropane triglycidyl ether, Any epoxy crosslinking agent or curing agent; vinyltrimethoxysilane, methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-aminopropyl Silane-based crosslinking agents or curing agents such as trimethoxysilane and N- (2-aminoethyl) 3-aminopropyltrimethoxysilane; melamine resin-based crosslinking agents; metal chelate-based crosslinking agents; amine-based crosslinking agents are used. The blending amount of the crosslinking agent or curing agent is preferably 0.001 to 10 parts by weight, more preferably 0.01 to 3 parts by weight with respect to 100 parts by weight of the main polymer. When the addition amount of the crosslinking agent or curing agent is less than 0.001 part by weight, the effect of the crosslinking agent is not exhibited, and foaming and peeling are conspicuous in a weather resistance test or the like. On the other hand, when the addition amount of the crosslinking agent or the curing agent is more than 10 parts by weight, the stress relaxation property of the pressure-sensitive adhesive is lowered, and warpage becomes conspicuous.

  Examples of the antioxidant include phenol-based antioxidants such as tetrakis (methylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate) methane, phosphorus-based antioxidants, and thioether-based antioxidants. Agents. The blending amount of the antioxidant is within a range in which the transparency and adhesive strength of the adhesive layer are not lowered.

  The adhesive composition preferably has a shear storage modulus at a temperature of 23 ° C. of 0.1 to 10 MPa. By setting it as the shear storage elastic modulus of this range, an adhesive composition can have moderate adhesiveness. However, not limited to this, a so-called hot melt type adhesive having a higher shear storage modulus can also be used as the adhesive composition.

  The adhesive composition preferably has a refractive index in the range of 1.40 to 1.55. By setting the refractive index within such a range, interface reflection can be easily prevented and optical performance can be improved.

  The method for preparing the pressure-sensitive adhesive composition is not limited as long as a uniform mixing and dispersion state can be obtained. For example, the above-mentioned components can be mixed by heating, stirring, ultrasonic treatment, or the like.

  In the present invention, the thickness of the adhesive layer is 5 to 30 μm, preferably 10 to 25 μm. Adhesive strength can be secured by setting the film thickness to 5 μm or more, while optical performance such as transmittance can be maintained by setting the film thickness to 30 μm or less.

(Use)
The polymerizable liquid crystal film and optical film of the present invention can be used as a member of a liquid crystal display device and can be used as a display medium for preventing forgery. Examples of anti-counterfeiting applications include containers for medicines, cosmetics, perfumes and toners, opening seals, packaging, banknotes, securities, cash vouchers, passports, electronic devices, bags, clothes, fabrics, credit cards, security cards, information Used as a display medium for the prevention of counterfeiting of articles with various codes (for example, one-dimensional codes such as barcodes and two-dimensional codes such as QR codes (registered trademark)), and various certifications it can.

  Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to the following examples, and can be implemented with any modifications without departing from the scope of the claims of the present invention and the equivalents thereof.

In the following description, “%” and “part” representing amounts are based on weight unless otherwise specified.
The following operations were performed in a normal temperature and normal pressure atmosphere unless otherwise specified.

  In the following examples and comparative examples, the measurement of chromaticity and visible light average reflectance is performed with respect to the normal of the surface to be measured using a spectrophotometer V-550 (light source D65) manufactured by JASCO Corporation. Light was incident from a direction of 5 °, and measurement was performed from a direction of 5 ° with respect to the normal, which is symmetric with respect to the direction of the incident light and the normal.

(Production Example 1: Cholesteric resin layer 1)
(P1-1: Transparent resin substrate having an alignment film)
Both surfaces of a film made of an alicyclic olefin polymer (trade name “ZEONOR FILM ZF14-100” manufactured by Optes Co., Ltd.) were subjected to corona discharge treatment. An aqueous solution of 5% polyvinyl alcohol was applied to one side of the film using a # 2 wire bar, and the coating film was dried to form an alignment film having a thickness of 0.1 μm. Next, the alignment film was rubbed to prepare a transparent resin substrate having the alignment film.

(P1-2: Formation of cholesteric resin layer)
Compound (1) 25.5 parts, polymerizable non-liquid crystal compound (2) 11 parts, chiral agent (trade name: LC756 / BASF) 2.3 parts, polymerization initiator (trade name; Irgacure OXE02 / Ciba Specialty Chemicals) A cholesteric liquid crystal composition was prepared by mixing 1.2 parts of a surfactant (trade name; KH40 / Seimi Chemical Co., Ltd.) 0.04 part with 60 parts of cyclopentanone. Compounds (1) and (2) are compounds having the following structures, respectively.

  Compound (1) was prepared according to the method described in International Publication No. WO2009 / 041512, and Compound (2) was prepared according to the method described in JP-A-11-10055.

Example 1
The cholesteric liquid crystal composition was applied to the surface having the alignment film of the transparent resin substrate having the alignment film prepared in (P1-1) using a # 10 wire bar. The coating film was subjected to an orientation treatment at 100 ° C. for 5 minutes, and an irradiation treatment (semi-curing treatment) with 100 mJ / cm ² ultraviolet rays was performed on the coating film to produce a polymerizable liquid crystal layer having a dry film thickness of 4 μm. The produced polymerizable liquid crystal layer was provided with a pyramidal concavo-convex mold having an apex angle of 90 °, a height of 2 μm, and a pitch of 4 μm, and shaped at 5 MPa and a temperature of 80 ° C. for 1 minute. After imparting the shape, an optical film 1 having a cholesteric resin layer having a thickness of 3.8 μm was obtained by irradiating with ultraviolet rays of 500 mJ / cm ² (main curing treatment) in a nitrogen atmosphere. The surface shape of the optical film 1 was given an embossed uneven shape. The obtained optical film was subjected to a heat resistance test at 150 ° C. for 6 hours, but the uneven shape was maintained.

(Example 2)
The cholesteric liquid crystal composition was applied to the surface having the alignment film of the transparent resin substrate having the alignment film prepared in (P1-1) using a # 10 wire bar. The coating film was subjected to orientation treatment at 100 ° C. for 5 minutes, and irradiation treatment (semi-curing treatment) with 350 mJ / cm ² ultraviolet rays was performed on the coating film to produce a polymerizable liquid crystal layer having a dry film thickness of 4 μm. The produced polymerizable liquid crystal layer was provided with a concavo-convex mold similar to that in Example 1, and shaped at 10 MPa and a temperature of 80 ° C. for 0.5 minutes. After imparting the shape, an optical film 2 having a cholesteric resin layer having a thickness of 3.8 μm was obtained by irradiation with ultraviolet rays of 500 mJ / cm ² (main curing treatment) in a nitrogen atmosphere. The surface shape of the optical film 2 was given an embossed uneven shape. The optical film obtained in the same manner as in Example 1 was subjected to a heat resistance test at 150 ° C. for 6 hours, but the uneven shape was maintained.

(Comparative Example 1)
An optical film 3 was obtained in the same manner as in Example 1 except that the amount of ultraviolet irradiation in the semi-curing treatment was changed to 500 mJ / cm ² . The surface shape of the optical film 3 was insufficient to give the embossed uneven shape.

(Comparative Example 2)
An optical film 4 was obtained in the same manner as in Example 2 except that the amount of ultraviolet irradiation in the semi-curing treatment was changed to 500 mJ / cm ² . The surface shape of the optical film 4 was insufficient to give the embossed uneven shape.

10, 30 Polymerizable liquid crystal film 11, 31 Semi-cured polymerizable liquid crystal film having surface shape 12, 32 Optical film having surface shape 100, 200, 300 Base film 110a, 310a Polymerizable liquid crystal layer 110b, 210b, 310b Polymerizable liquid crystal layers 110c and 210c having a surface shape Layers 120, 220, and 320 that are obtained by curing the liquid crystal layer 240 Table for press 330 Adhesive layer 340 Base film for transfer

Claims (7)

The manufacturing method of the optical film which has the surface shape characterized by including the process of following (1), (2), and (4).
(1) A step of forming a polymerizable liquid crystal layer by applying a polymerizable liquid crystal composition to a base film.
(2) A step of semi-curing the polymerizable liquid crystal layer.
(4) A step of imparting a surface shape to the semi-cured polymerizable liquid crystal layer. Furthermore, the following process (3) is included after the said process (2) and before the said process (4), The manufacturing method of the optical film of Claim 1 characterized by the above-mentioned.
(3) A step of transferring the semi-cured polymerizable liquid crystal layer to a transfer substrate film. Furthermore, the following process is included, The manufacturing method of the optical film of Claim 1 or 2 characterized by the above-mentioned.
(5) A step of fully curing the polymerizable liquid crystal layer imparted with the surface shape.   A polymerizable liquid crystal film produced by the steps (1) to (2).   The film which has the polymeric liquid crystal layer which has the surface shape manufactured by the method of Claim 1 or 2.   The optical film which has the surface shape manufactured by the process of said (1)-(5).   An optical film having a surface shape produced by the steps (1), (2), (4), and (5).

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