JP2012181360A - Method for manufacturing laminate film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a laminate film capable of obtaining a laminate film containing a plurality of cholesteric liquid crystal layers and having a satisfactory film strength and suppressing generation of coating cissing defect.SOLUTION: A method for manufacturing a laminate film comprises steps of: (a) applying a curable liquid crystal composition containing a rod-like curable cholesteric liquid crystal compound, an alignment controlling agent, and an organic solvent on a support; (b) converting the curable liquid crystal composition applied to a cholesteric liquid crystal phase by heating the curable liquid crystal compound to align; (c) forming a cholesteric liquid crystal layer in which the cholesteric liquid crystal phase is fixed by radiating active radiation to the curable liquid crystal composition; (d) adhering a solvent to the surface of the cholesteric liquid crystal layer; (e) removing the alignment controlling agent eluted in the solvent adhered to the surface of the cholesteric liquid crystal layer; and (f) repeating at least once the (a) applying step, (b) aligning step, and (c) radiating step on the cholesteric liquid crystal layer in which the solvent is removed.

Description

  The present invention relates to a method for producing a laminated film. More specifically, the present invention relates to a method for producing a laminated film in which two or more cholesteric liquid crystal phases are laminated.

  In recent years, the need for industrial products related to energy saving has been increasing due to increasing interest in the environment and energy. As one of them, there is a demand for a light-reflective film for glass that is effective in shielding heat from window glass of houses, automobiles, etc., that is, reducing the heat load caused by sunlight.

  A multi-layer glass coated with a special metal film that cuts off heat radiation, called Low-E pair glass, is often used as eco-glass with high heat insulation and heat shielding properties. The special metal film can be manufactured by laminating a plurality of layers by, for example, a vacuum film forming method. However, the vacuum process has low productivity and high production cost. Further, in applications of light reflecting films for glass, light transmittance is often required for wavelengths other than the target reflection wavelength. For example, automobile windows have low haze and infrared light from the viewpoint of safety. High transparency is required such that visible light is required to have high transparency while reflecting light. However, when a metal film is used, high transparency is not always satisfactory, and other improvements are also required from the viewpoint of radio wave transmission.

  On the other hand, an infrared light reflection film in which a layer formed by fixing a curable cholesteric liquid crystal phase on a support is laminated (for example, see Patent Document 1). Patent Document 1 describes a method of extending the reflection wavelength of a laminated film to a desired band by performing laminated film formation of a cholesteric liquid crystal layer. Further, in Patent Document 1, as a method of laminating a plurality of cholesteric liquid crystal layers, a curable liquid crystal composition containing a rod-like curable cholesteric liquid crystal compound and an alignment control agent for controlling the alignment is applied and heated alignment. And a step of repeating the UV curing step and coating the cholesteric liquid crystal layer one layer at a time.

JP 2010-286643 A Japanese Patent No. 3554619 JP 2004-258405 A JP 2006-064834 A

  However, it is found that when the curable liquid crystal composition for the second cholesteric liquid crystal layer is applied on the first cholesteric liquid crystal layer, the coating liquid is repelled and an uncoated region is formed. It was.

  As a result of the examination of the cause by the present inventors, it has been found that the alignment control agent contained in the first cholesteric liquid crystal layer has a great influence on the occurrence of repelling. The alignment control agent contributes to the alignment control of the rod-like liquid crystal, but a fluorine-based material is generally used, and in this case, it is unevenly distributed on the surface of the cholesteric liquid crystal layer between the coating process and the irradiation process. Here, when the alignment control agent is present in a large amount on the film surface, the surface energy of the film is lowered, and repelling occurs when the second liquid crystal layer is applied, thereby forming an uncoated region. On the other hand, the alignment control agent adjusts the addition amount of the alignment control agent in the coating liquid by causing alignment defects and reticulation depending on the addition amount and causing deterioration of the surface shape and haze (transparency of the film). It is difficult. It is also possible to add an alignment control agent for non-fluorine materials, but the ability to orient liquid crystals on the surface is low as in fluorine materials, and the amount added is higher than in fluorine materials, so the inside of the film In many cases, the orientation deteriorates more than the fluorine-based material.

  Further, the inventors further studied and found that when the UV irradiation amount to the curable liquid crystal composition is increased, the repellency tends to be suppressed. However, it was found that when the UV irradiation amount is lowered, the laminated film obtained by laminating the obtained cholesteric liquid crystal layer has insufficient film hardness, and it is difficult to adjust the UV irradiation amount.

On the other hand, a method is known in which foreign substances present on the surface of the cholesteric liquid crystal layer are physically reduced and removed uniformly before the coating step. For example, as a method for removing dust on the surface, Patent Document 2 describes removal by a surface dust remover and an adhesive roller. However, it has been difficult to reduce or remove the alignment control agent contained in the surface of the first cholesteric liquid crystal layer by physical contact with an air suction / adhesion roller.
Patent Document 3 describes a method for producing a cholesteric liquid crystal laminate in which two or more cholesteric liquid crystal layers are laminated by a coating method. In Patent Document 3, as a method of concentration-distributing a substance that causes a change in cholesteric pitch length after coating film formation in the thickness direction, the liquid crystal layer is washed with a solvent after the coating film formation, thereby removing the liquid crystal layer from the liquid crystal layer. A method of extracting a substance and utilizing the fact that the amount of extraction differs in the thickness direction is described. However, Patent Document 3 does not mention an alignment control agent or other surfactants.
Further, Patent Document 4 discloses a composition comprising a transparent support, a polymer layer on the support, and at least one liquid crystal compound and at least one fluorine-containing horizontal alignment agent on the surface of the polymer layer. A method for producing an optical compensation sheet having a formed optically anisotropic layer is described. In Patent Document 4, after forming an optically anisotropic layer, it is immersed in an aqueous sodium hydroxide solution at 55 ° C. for 2 minutes, followed by washing in a water-washing bath at room temperature to saponify the film surface, thereby forming a polarizing film. It is described that a protective film with improved adhesion can be obtained. However, Patent Document 4 does not discuss about further laminating the second liquid crystal compound after removing the horizontal alignment agent.

  That is, the problem to be solved by the present invention is a method for producing a laminated film that includes two or more layers containing cholesteric liquid crystals, can obtain a laminated film with good film strength, and can suppress the occurrence of coating repellency. Is to provide.

  Even when the film strength is increased by sufficiently polymerizing the lower cholesteric liquid crystal layer, the present inventors attach a solvent to the lower cholesteric liquid crystal layer before the coating process of the second and subsequent cholesteric liquid crystal layers. It was found that the alignment control agent present on the surface of the lower cholesteric liquid crystal layer can be uniformly reduced or removed by eluting and diffusing the alignment control agent into the solvent and removing the solvent. As a result, the present inventors have completed a method for producing a laminated film that has good film strength and can suppress the occurrence of coating repellency, and has found that the above problems can be solved.

Means for solving the above problems are as follows.
[1] An application step of applying (a) a curable liquid crystal composition containing a rod-like curable cholesteric liquid crystal compound, an alignment controller and an organic solvent on a support; and (b) the applied curable liquid crystal composition. An alignment step of applying heat to the product to align the curable liquid crystal compound to form a cholesteric liquid crystal phase; and (c) irradiating the curable liquid crystal composition with active radiation to form a cholesteric liquid crystal phase. An irradiation step for forming a fixed cholesteric liquid crystal layer; (d) a solvent attachment step for attaching a solvent to the surface of the cholesteric liquid crystal layer; and (e) the alignment eluted in the solvent attached to the surface of the cholesteric liquid crystal layer. An alignment control agent removing step of removing the control agent; and (f) the (a) coating step, the (b) alignment step, and the (() above the cholesteric liquid crystal layer from which the solvent has been removed. c) A method for producing a laminated film comprising a laminating step of laminating a cholesteric liquid crystal layer by repeating the irradiation step at least once.
[2] The method for producing a laminated film according to [1], wherein (d) the solvent attaching step is spraying of a solvent with a nozzle.
[3] The method for producing a laminated film according to [1], wherein the (d) solvent adhesion step is immersion in a solvent.
[4] In the solvent attached to the surface of the cholesteric liquid crystal layer, 70% or more of the alignment control agent contained in the curable liquid crystal composition in the coating step (a) is eluted. The method for producing a laminated film according to any one of [1] to [3].
[5] In the (d) solvent adhesion step, the same compound as the organic solvent contained in the curable liquid crystal composition in the coating step (a) is used as the solvent. 4] The manufacturing method of the laminated | multilayer film as described in any one of [4].
[6] The laminate according to any one of [1] to [5], wherein the solvent used in the (d) solvent attaching step includes at least one of cyclohexanone, tetrahydrofuran, and methyl ethyl ketone. A method for producing a film.
[7] The method according to any one of [1] to [6], wherein (e) the solvent removal step is performed after 10 seconds or more have elapsed since the start of the (d) solvent adhesion step. A method for producing a laminated film.
[8] Any one of [1] to [8], wherein the (e) alignment control agent removing step is scraping with a roller having a surrounding material coated with a material lower than the surface hardness of the cholesteric liquid crystal layer. A method for producing a laminated film according to claim 1.
[9] The method for producing a laminated film according to [8], including a step of attaching a solvent to the surface of the roller before scraping with the roller.
[10] The method for producing a laminated film as described in [9], wherein the same compound as the solvent in (d) solvent adhesion is used as the solvent to be adhered to the roller surface.
[11] In the (e) alignment control agent removing step, the amount of the alignment control agent contained in the surface of the cholesteric liquid crystal layer is included in the curable liquid crystal composition in the (a) coating step. The method for producing a laminated film according to any one of [1] to [10], wherein the solvent is removed so as to be 10% or less of the control agent:
Here, the amount of the alignment control agent contained on the surface of the cholesteric liquid crystal layer is preferably measured by the following method (T). However, the details of the measurement conditions may be optimized as appropriate depending on the type of the orientation control agent to be measured.
<Method (T)>
The film on which the 20 × 20 cm cholesteric liquid crystal composition is formed is immersed in a predetermined amount of MEK, and the alignment control agent present on the film surface is dissolved in MEK. Using this as a sample solution, using high-performance liquid chromatography, using an eluent (tetrahydrofuran: pure water = 4: 1 (volume ratio)) and measuring a wavelength of 275 nm using an ultraviolet absorptiometer for 40 minutes, the signal obtained The concentration of the alignment control agent measured when the alignment control agent eluted from the surface area is calculated.
[12] Any one of [1] to [11], wherein the cholesteric liquid crystal layer includes at least one layer that reflects right circularly polarized light and one layer that reflects left circularly polarized light. The manufacturing method of the laminated | multilayer film as described in a term.
[13] The method for producing a laminated film according to any one of [1] to [12], wherein the cholesteric liquid crystal layer includes at least one layer that reflects infrared light having a wavelength of 800 nm or more. .

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the laminated | multilayer film which can obtain the laminated | multilayer film which contains two or more layers containing a cholesteric liquid crystal, and whose film | membrane intensity | strength is favorable, and can suppress generation | occurrence | production of a coating repellency can be provided. .

It is the schematic of an example of the manufacturing apparatus used for the manufacturing method of this invention. It is the schematic of another example of the manufacturing apparatus used for the manufacturing method of this invention. It is the schematic of another example of the manufacturing apparatus used for the manufacturing method of this invention. It is the schematic of another example of the manufacturing apparatus used for the manufacturing method of this invention. It is the schematic which showed an example of the cross section of the laminated | multilayer film manufactured by the manufacturing method of this invention. It is the schematic which showed an example of the cross section of the laminated glass manufactured using the laminated | multilayer film manufactured by the manufacturing method of this invention.

  Hereinafter, the contents of the present invention will be described in detail. The description of the constituent elements described below may be made based on typical embodiments of the present invention, but the present invention is not limited to such embodiments. In the present specification, “to” is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value.

[Production method of laminated film]
The method for producing a laminated film of the present invention comprises: (a) a coating step of coating a curable liquid crystal composition containing a rod-shaped curable cholesteric liquid crystal compound, an alignment controller and an organic solvent on a support; and (b) coating. An alignment step in which the curable liquid crystal composition is heated to align the curable liquid crystal compound to form a cholesteric liquid crystal phase; and (c) active radiation is applied to the curable liquid crystal composition. An irradiation step of forming a cholesteric liquid crystal layer in which the cholesteric liquid crystal phase is fixed by irradiation; (d) a solvent attachment step of attaching a solvent to the surface of the cholesteric liquid crystal layer; and (e) an attachment to the surface of the cholesteric liquid crystal layer. An alignment control agent removing step of removing the alignment control agent eluted in the solvent, and (f) applying the step (a) on the cholesteric liquid crystal layer from which the solvent has been removed. (B) is repeated at least once an alignment step and the (c) irradiation process, characterized in that it comprises a lamination step of laminating a cholesteric liquid crystal layer. In addition, the manufacturing method of the laminated | multilayer film of this invention is also called the manufacturing method of this invention.

The alignment control agent contained in the first cholesteric liquid crystal layer formed on the support is generally a fluorine-based material, and in this case, it is unevenly distributed on the surface of the cholesteric liquid crystal layer between the coating step and the irradiation step. . Here, when a large amount of the alignment control agent is present on the surface of the cholesteric liquid crystal layer of the first layer, the surface energy of the cholesteric liquid crystal layer of the first layer is lowered, and the cause of repelling when applying the liquid crystal layer of the second and subsequent layers It becomes. On the other hand, when the irradiation amount of active ultraviolet rays is increased to increase the film strength (that is, when the degree of polymerization of the first cholesteric liquid crystal layer is increased), the orientation control is performed by forming a molecular network on the surface of the first cholesteric liquid crystal layer. The agent will be fixed. Therefore, when the irradiation amount of the active ultraviolet ray is increased, the alignment control agent for the lower cholesteric liquid crystal layer can be sufficiently eluted in the solvent contained in the curable liquid crystal composition in the second and subsequent layers. In other words, coating repelling occurred.
On the other hand, the production method of the present invention allows a sufficient amount of active ultraviolet light to be irradiated by positively removing the alignment control agent eluted by adhering a solvent to the surface of the cholesteric liquid crystal layer and eluting the adhering solvent. Even when the degree of polymerization of the first cholesteric liquid crystal layer is increased to reduce the surface energy of the first cholesteric liquid crystal layer, the curable liquid crystal composition of the second layer is repelled when applied. Can be prevented from occurring.
Hereinafter, materials and processes that are preferably used in the production method of the present invention will be described.

(A) Application process:
The production method of the present invention includes an application step of applying (a) a curable liquid crystal composition containing a rod-shaped curable cholesteric liquid crystal compound, an alignment controller and an organic solvent on a support.

(Support)
There is no restriction | limiting in particular as a support body used for the manufacturing method of the laminated film of this invention, A cholesteric liquid crystal layer is apply | coated on arbitrary supports, and a laminated film can be manufactured. As the support, for example, a polymer film, a glass plate, a quartz plate, or the like can be used, and a polymer film having high transparency to visible light is preferably used.
Examples of the polymer film having high transparency to visible light include polymer films for various optical films used as members of display devices such as liquid crystal display devices. Examples of the polymer film include polyester films such as polyethylene terephthalate (PET), polybutylene terephthalate, and polyethylene naphthalate (PEN); polycarbonate (PC) films and polymethyl methacrylate films; polyolefin films such as polyethylene and polypropylene; polyimide films, A triacetyl cellulose (TAC) film is preferred, polyethylene terephthalate and triacetyl cellulose are more preferred, and polyethylene terephthalate is particularly preferred.

(Components of curable liquid crystal composition)
Curable cholesteric liquid crystal compounds:
The curable liquid crystal composition used in the method of the present invention contains a rod-like curable cholesteric liquid crystal compound. The rod-like curable cholesteric liquid crystal compound is preferably a polymerizable cholesteric liquid crystal compound.

  An example of a rod-like curable cholesteric liquid crystal compound that can be used in the present invention is a rod-like nematic liquid crystal compound. Examples of the rod-like nematic liquid crystal compounds include azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoates, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, alkoxy-substituted Phenylpyrimidines, phenyldioxanes, tolanes and alkenylcyclohexylbenzonitriles are preferably used. Not only low-molecular liquid crystal compounds but also high-molecular liquid crystal compounds can be used.

  In the production method of the present invention, the curable liquid crystal composition exhibits a cholesteric liquid crystal phase, and the curable liquid crystal composition contains at least one curable cholesteric liquid crystal compound.

  The polymerizable cholesteric liquid crystal compound can be obtained by introducing a polymerizable group into the cholesteric liquid crystal compound. Examples of the polymerizable group include an unsaturated polymerizable group, an epoxy group, and an aziridinyl group, preferably an unsaturated polymerizable group, and particularly preferably an ethylenically unsaturated polymerizable group. The polymerizable group can be introduced into the molecule of the cholesteric liquid crystal compound by various methods. The number of polymerizable groups possessed by the polymerizable cholesteric liquid crystal compound is preferably 1 to 6, more preferably 1 to 3. Examples of polymerizable cholesteric liquid crystal compounds are described in Makromol. Chem. 190, 2255 (1989), Advanced Materials 5, 107 (1993), US Pat. No. 4,683,327, US Pat. No. 95/24455, No. 97/00600, No. 98/23580, No. 98/52905, JP-A-1-272551, No. 6-16616, and No. 7-110469. 11-80081 and JP-A 2001-328773, and the like. Two or more kinds of polymerizable cholesteric liquid crystal compounds may be used in combination. When two or more kinds of polymerizable cholesteric liquid crystal compounds are used in combination, the alignment temperature can be lowered.

  Moreover, it is preferable that the addition amount of the rod-shaped curable cholesteric liquid crystal compound in the said curable liquid crystal composition is 10-50 mass% with respect to the curable liquid crystal composition, and is 20-40 mass%. Is more preferable, and it is especially preferable that it is 25-35 mass%.

Organic solvent:
The organic solvent for dissolving the curable cholesteric liquid crystal compound is not particularly limited, and a known solvent can be used. For example, ketones (acetone, 2-butanone, methyl isobutyl ketone, cyclohexanone, etc.), ethers (dioxane, tetrahydrofuran, etc.), aliphatic hydrocarbons (hexane, etc.), alicyclic hydrocarbons (cyclohexane, etc.), aromatic Group hydrocarbons (toluene, xylene, trimethylbenzene, etc.), halogenated carbons (dichloromethane, dichloroethane, dichlorobenzene, chlorotoluene, etc.), esters (methyl acetate, ethyl acetate, butyl acetate, etc.), water, alcohols ( Ethanol, isopropanol, butanol, cyclohexanol, etc.), cellosolves (methyl cellosolve, ethyl cellosolve, etc.), cellosolve acetates, sulfoxides (dimethylsulfoxide, etc.), amides (dimethylformamide, di Such as chill acetamide), etc. can be exemplified.
In the production method of the present invention, one or more organic solvents can be used, and two or more organic solvents are preferably used.

Orientation control agent:
The alignment control agent that can be used in the present invention is not particularly limited. Preferred examples thereof include compounds represented by the following general formulas (I) to (IV). You may contain 2 or more types selected from these. These compounds can reduce the tilt angle of the molecules of the liquid crystal compound or can be substantially horizontally aligned at the air interface of the layer.
In this specification, “horizontal alignment” means that the major axis of the liquid crystal molecule is parallel to the film surface, but it is not required to be strictly parallel. An orientation with an inclination angle of less than 20 degrees is meant. When the liquid crystal compound is horizontally aligned in the vicinity of the air interface, alignment defects are unlikely to occur, so that the transparency in the visible light region is increased and the reflectance in the infrared region is increased. On the other hand, if the molecules of the liquid crystal compound are aligned at a large tilt angle, the spiral axis of the cholesteric liquid crystal phase is shifted from the normal to the film surface, which decreases the reflectivity, generates a fingerprint pattern, increases haze, and increases diffraction. It is not preferable because it shows sex.

In the general formula, each R may be the same or different and represents an alkoxy group having 1 to 30 carbon atoms which may be substituted with a fluorine atom, more preferably an alkoxy group having 1 to 20 carbon atoms, More preferred is an alkoxy group having 1 to 15 carbon atoms. However, one or more CH ₂ in the alkoxy group and two or more CH ₂ not adjacent to each other are —O—, —S—, —OCO—, —COO—, —NR ^a —, —NR ^a CO—, — It may be substituted with CONR ^a- , -NR ^a SO _2- , or -SO ₂ NR ^a- . R ^a represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.
The alignment control agent may be a fluorine-based material having one or more fluorine atoms as a substituent, or a non-fluorine-based material. Among them, the addition of a fluorine-based material alignment control agent has a higher ability to align the liquid crystal on the surface than the addition of a non-fluorine-based material alignment control agent, and the amount added can be reduced compared to a non-fluorine-based material. This is preferable because it tends to reduce the orientation inhibiting factor in the film and improve the orientation.
The orientation controlling agent preferably has a terminal carbon atom substituted with a fluorine atom, and preferably has a perfluoroalkyl group at the terminal.
Preferred examples of R include
-OC _n H <sub>2n + 1
- (OC 2 H 4) n1</sub> (CF 2) n2 F
_{- (OC 3 H 6) n1} (CF 2) n2 F
_{- (OC 2 H 4) n1} NR a SO 2 (CF 2) n2 F
_{- (OC 3 H 6) n1} NR a SO 2 (CF 2) n2 F
In the above formula, n, n1, and n2 are each an integer of 1 or more, n is preferably 1-20, more preferably 5-15; n1 is 1-10. Preferably, it is 1-5, more preferably; n2 is preferably 1-10, more preferably 2-10.
In the formula, m1, m2, and m3 each represent an integer of 1 or more.
m1 is preferably 1 or 2, and more preferably 2. When it is 1, it is preferable that R is substituted at the para position and the meta position when it is para position and 2.
m2 is preferably 1 or 2, and more preferably 1. When it is 1, it is preferable that R is substituted at the para position and the meta position when it is para position and 2.
m3 is preferably 1 to 3, and R is preferably substituted at two meta positions and one para position with respect to —COOH.

Examples of the compound of the formula (I) include compounds exemplified in [0092] and [0093] of JP-A-2005-99248.
Examples of the compound of the formula (II) include compounds exemplified in [0076] to {0078} and [0082] to [0085] of JP-A No. 2002-129162.
Examples of the compound of the formula (III) include compounds exemplified in [0094] and [0095] of JP-A-2005-99248.
Examples of the compound of the formula (IV) include compounds exemplified in [0096] of JP-A-2005-99248.
The amount of the alignment control agent used is preferably 0.001 to 1% by mass, based on the curable cholesteric liquid crystal compound (solid content in the case of a coating solution), and is 0.005 to 0.5% by mass. It is more preferable that it is 0.01-0.01 mass%.

Chiral agent (optically active compound):
The curable liquid crystal composition exhibits a cholesteric liquid crystal phase, and therefore needs to contain a chiral agent.
The chiral agent generally contains an asymmetric carbon atom, but an axially asymmetric compound or a planar asymmetric compound that does not contain an asymmetric carbon atom can also be used as the chiral agent. Examples of the axial asymmetric compound or the planar asymmetric compound include binaphthyl, helicene, paracyclophane, and derivatives thereof. The chiral agent may have a polymerizable group. When the chiral agent and the curable cholesteric liquid crystal compound have a polymerizable group, it is derived from a repeating unit derived from the cholesteric liquid crystal compound and the chiral agent by a polymerization reaction between the polymerizable chiral agent and the polymerizable cholesteric liquid crystal compound. A polymer having repeating units can be formed. In this embodiment, the polymerizable group possessed by the polymerizable chiral agent is preferably the same group as the polymerizable group possessed by the polymerizable cholesteric liquid crystal compound. Therefore, the polymerizable group of the chiral agent is also preferably an unsaturated polymerizable group, an epoxy group or an aziridinyl group, more preferably an unsaturated polymerizable group, and an ethylenically unsaturated polymerizable group. Particularly preferred.
The chiral agent may be a liquid crystal compound.
The concentration of the chiral agent in the curable liquid crystal composition can be arbitrarily changed depending on the target wavelength with respect to the rod-shaped curable cholesteric liquid crystal compound used in combination. % Is preferred.

Polymerization initiator:
The curable liquid crystal composition preferably contains a polymerization initiator. In the embodiment in which the polymerization reaction is advanced by ultraviolet irradiation, the polymerization initiator to be used is preferably a photopolymerization initiator that can start the polymerization reaction by ultraviolet irradiation. Examples of the photopolymerization initiator include α-carbonyl compounds (described in US Pat. Nos. 2,367,661 and 2,367,670), acyloin ether (described in US Pat. No. 2,448,828), α-hydrocarbon substituted aromatics. Group acyloin compounds (described in US Pat. No. 2,722,512), polynuclear quinone compounds (described in US Pat. Nos. 3,046,127 and 2,951,758), combinations of triarylimidazole dimers and p-aminophenyl ketone (US patents) No. 3549367), acridine and phenazine compounds (JP-A-60-105667, US Pat. No. 4,239,850), oxadiazole compounds (US Pat. No. 4,221,970), and the like. .
The amount of the photopolymerization initiator used is preferably 0.1 to 20% by mass, preferably 1 to 8% by mass, based on the curable cholesteric liquid crystal compound (in the case of a coating solution, solid content). Is more preferable.

Other additives:
In addition, the liquid crystal composition contains at least one selected from various additives such as a non-uniformity inhibitor, a repellency inhibitor, and a polymerizable monomer in order to improve alignment uniformity, coating suitability, and film strength. You may do it. Further, in the liquid crystal composition, a polymerization inhibitor, an antioxidant, an ultraviolet absorber, a light stabilizer, a colorant, metal oxide fine particles, and the like are added in a range that does not deteriorate the optical performance, if necessary. Can be added.

(Preparation of polymerizable liquid crystal composition)
The polymerizable liquid crystal composition is prepared as a coating solution in which a material is dissolved and / or dispersed in the organic solvent. In the production method of the present invention, it is preferable to add a photopolymerization initiator to the polymerizable liquid crystal composition.
The coating process of the present invention is completed on the surface of the support such as the polymer film, glass plate, quartz plate or the like, if necessary, after the polymerizable liquid crystal composition is completed as a coating solution. It is preferable to apply to the surface of the formed alignment film. The polymerizable liquid crystal composition can be applied by various methods such as a wire bar coating method, an extrusion coating method, a direct gravure coating method, a reverse gravure coating method, and a die coating method.

Drying process:
The manufacturing method of the present invention may have a drying step of drying the applied polymerizable liquid crystal composition in addition to the coating step, the alignment step, and the irradiation step. The drying step may be performed at any timing, but is preferably performed after the coating step, and is preferably performed after the coating step and before the alignment step. Moreover, the said drying process can be performed without a restriction | limiting by heating, ventilation, and other methods.

(B) Orientation process:
The production method of the present invention includes (b) an alignment step in which heat is applied to the applied curable liquid crystal composition to align the curable liquid crystal compound so that the cholesteric liquid crystal phase is obtained.
In order to obtain a transition temperature to the cholesteric liquid crystal phase, heat is applied to the applied polymerizable liquid crystal composition. As a method of applying the heat, for example, the cholesteric liquid crystal phase can be stably brought into a state by, for example, once heating to an isotropic phase temperature and then cooling to a cholesteric liquid crystal phase transition temperature. The liquid crystal phase transition temperature of the polymerizable liquid crystal composition is preferably in the range of 10 to 250 ° C., more preferably in the range of 10 to 150 ° C. from the viewpoint of production suitability and the like. If it is 10 ° C. or more, it is easy to make the temperature range exhibiting a liquid crystal phase, and if it is 200 ° C. or less, it is preferable from the viewpoint of consumption of heat energy, and it is also advantageous for deformation and alteration of the substrate. .
In order to align the polymerizable cholesteric liquid crystal compound into a cholesteric liquid crystal phase, it is preferable to apply heat at 80 to 90 ° C. for 1.5 to 5 minutes.

(C) Irradiation process:
The manufacturing method of this invention includes the irradiation process of irradiating actinic radiation with respect to the said curable liquid crystal composition, and forming the cholesteric liquid crystal layer which fixed the cholesteric liquid crystal phase.
As the active radiation, ultraviolet rays or the like can be used. In an embodiment using ultraviolet irradiation, a light source such as an ultraviolet lamp is used. In this step, the cholesteric liquid crystal phase is fixed by irradiating ultraviolet rays, and a cholesteric liquid crystal layer (preferably an infrared light reflection layer) is formed.

The irradiation energy amount of actinic radiation is not particularly limited as long as sufficient film hardness can be obtained without departing from the spirit of the present invention. The dose of actinic radiation (preferably ultraviolet light) from the viewpoint of film hardness and surface as long as it is desirable to increase possible, preferably ^{250mJ / cm 2 ~800mJ / cm 2} , 300~500mJ / cm 2 is more preferable.

  In order to accelerate the reaction of fixing the cholesteric liquid crystal phase, actinic radiation irradiation may be performed under heating conditions. Moreover, it is preferable to maintain the temperature at the time of irradiation with actinic radiation in a temperature range exhibiting a cholesteric liquid crystal phase so that the cholesteric liquid crystal phase is not disturbed. Also, since the oxygen concentration in the atmosphere is related to the degree of polymerization, if the desired degree of polymerization is not reached in the air and the film strength is insufficient, the oxygen concentration in the atmosphere is reduced by a method such as nitrogen substitution. It is preferable. A preferable oxygen concentration is preferably 10% or less, more preferably 7% or less, and most preferably 3% or less.

  In the irradiation step, the cholesteric liquid crystal phase is fixed and a cholesteric liquid crystal layer is formed. Here, the state in which the liquid crystal phase is “fixed” is the most typical and preferred mode in which the orientation of the liquid crystal compound in the cholesteric liquid crystal phase is maintained. However, it is not limited to this, and specifically, it is usually 0 ° C. to 50 ° C., and under severer conditions, in the temperature range of −30 ° C. to 70 ° C., the layer has no fluidity, and is oriented by an external field or an external force. It shall mean a state in which the fixed orientation form can be kept stable without causing a change in form. In the present invention, the alignment state of the cholesteric liquid crystal phase is fixed by irradiation with actinic radiation.

  In the present invention, it is sufficient that the optical properties of the cholesteric liquid crystal phase are maintained in the layer, and the liquid crystal composition in the cholesteric liquid crystal layer is no longer required to exhibit liquid crystal properties. For example, the liquid crystal composition may have a high molecular weight due to a curing reaction and may no longer have liquid crystallinity.

(D) Solvent adhesion step:
The production method of the present invention includes a solvent attaching step of attaching a solvent to the surface of the cholesteric liquid crystal layer.

(Method)
There is no restriction | limiting in particular as long as it is not contrary to the meaning of this invention as a method of the said solvent adhesion process. For example, spraying of a solvent with a nozzle, immersion in a solvent, roll coating, curtain coating, slit coating, and the like can be given.
In the manufacturing method of this invention, it is preferable that the said solvent adhesion process is spraying of the solvent by a nozzle, or immersion in a solvent.

The spraying of the solvent by the nozzle can be performed by spraying the solvent on one or both surfaces of the laminated film in which the cholesteric liquid crystal layer is formed on the support. Among these, it is preferable to spray the solvent 41 from the nozzle 42 only on the surface of the laminated film on the cholesteric liquid crystal layer side using the apparatus shown in FIG. Spraying of such solvents is preferably 1~1000ml / m ² with respect to the laminated film, more preferably 10~500ml / m ^2, and particularly preferably 30 to 100 / m ² .

The immersion in the solvent can be performed by, for example, a method of transporting the inside of the solvent by the immersion roll 46 disposed inside the solvent tank 45 using the apparatus shown in FIG. The immersion in the solvent is preferably 1 to 30 seconds, more preferably 2 to 20 seconds, and particularly preferably 5 to 10 seconds.
In addition, it is preferable that the said solvent tank 45 is shared with the solvent tank in the case of using a scraping roll in the solvent removal process mentioned later and attaching a solvent to the scraping roll beforehand.

In the production method of the present invention, 50% or more of the alignment control agent contained in the curable liquid crystal composition in the coating step (a) is eluted in the solvent attached to the surface of the cholesteric liquid crystal layer. It is preferable to elute 70% or more, and it is particularly preferable to elute 90% or more. Such an elution amount is determined from the amount of the alignment control agent contained in the surface of the cholesteric liquid crystal layer before the solvent adhesion step, and from the amount of the alignment control agent contained in the surface of the cholesteric liquid crystal layer after the alignment control agent removal step described later. Can be obtained by reducing the amount.
In addition, how to obtain | require the quantity of the orientation control agent contained in the surface of a cholesteric liquid crystal layer is mentioned later in description of (e) orientation control agent removal process.

(Solvent type)
In the production method of the present invention, in the (d) solvent adhesion step, the solvent is not particularly limited as long as it does not contradict the gist of the present invention. In the present invention, although related to the type of the alignment control agent, it is preferable to use a solvent having sufficient compatibility with the alignment control agent, and the ΔSP value of both is preferably in the range of 0 to 10, A range of 0 to 5 is more preferable, and a range of 0 to 2 is particularly preferable.
As the solvent, for example, the organic solvent, cyclohexanone, tetrahydrofuran, cyclohexanol and the like contained in the curable liquid crystal composition in the coating step (a) can be used, and the curable liquid crystal in the coating step (a). It is preferable to use the same compound as the organic solvent contained in the composition.
In the production method of the present invention, the solvent used in the (d) solvent attaching step preferably contains at least one of cyclohexanone, tetrahydrofuran, cyclohexanol, and methyl ethyl ketone, preferably contains at least methyl ethyl ketone, It is particularly preferred.

(E) Orientation control agent removal step:
The production method of the present invention includes an alignment control agent removing step of removing the alignment control agent eluted in the solvent attached to the surface of the cholesteric liquid crystal layer. In the production method of the present invention, the alignment control agent is removed after the alignment control agent is eluted in the solvent attached in the solvent attaching step. At this time, the solvent attached in the solvent attaching step together with the alignment control agent may be removed at the same time, and the solvent attached in the solvent attaching step together with the orientation controlling agent is preferably removed at the same time.

(Timing of the orientation control agent removal process)
In the production method of the present invention, it is preferable to perform the (e) solvent removal step after 5 seconds or more have elapsed since the start of the (d) solvent adhesion step, and after 5 to 20 seconds have elapsed, It is more preferable to perform the solvent removal step, and it is particularly preferable to perform the (e) solvent removal step after 5 to 10 seconds have elapsed. By performing at such timing, the solvent adhering to the surface of the cholesteric liquid crystal layer in the solvent adhering step permeates the cholesteric liquid crystal layer, and the alignment control agent is sufficiently easily eluted.

(Orientation control agent removal method)
In the production method of the present invention, it is preferable that the (e) alignment control agent removing step is scraping with a scraping roller having a material lower than the surface hardness of the cholesteric liquid crystal layer coated around. Specifically, the surface hardness of the scraping roller is preferably H or less in pencil hardness.
Examples of the material having such a surface hardness include polyethylene terephthalate, Teflon rubber, cellulose, viton rubber and the like, and among these, viton rubber is preferably used.

In the manufacturing method of this invention, it is preferable from a viewpoint of the damage prevention of a film, and a washing | cleaning uniformity to include the process of making a solvent adhere to the scraping roller surface before scraping by the said roller. Such a process can be performed using the apparatus shown in FIG. 3 or FIG.
In the production method of the present invention, the solvent to be attached to the roller surface is not particularly limited, but it is preferable to use the same compound as the solvent in the (d) solvent attachment.

In the production method of the present invention, in the (e) alignment control agent removing step, the amount of the alignment control agent contained in the cholesteric liquid crystal layer measured by the following method (T) is curable in the (a) coating step. The solvent is preferably removed so as to be 50% or less of the alignment control agent contained in the liquid crystal composition, more preferably the solvent is removed so as to be 30% or less. It is particularly preferable to remove the solvent so that
<Method (T)>
The film on which the 20 × 20 cm cholesteric liquid crystal composition is formed is immersed in a predetermined amount of MEK, and the alignment control agent present on the film surface is dissolved in MEK. Using this as a sample solution, using high-performance liquid chromatography, using an eluent (tetrahydrofuran: pure water = 4: 1 (volume ratio)) and measuring a wavelength of 275 nm using an ultraviolet absorptiometer for 40 minutes, the signal obtained The concentration of the alignment control agent measured when the alignment control agent eluted from the surface area is calculated.

(F) Lamination process:
In the production method of the present invention, after the (e) solvent removal step, the (a) coating step, the (b) alignment step, and the (c) irradiation step are performed on the cholesteric liquid crystal layer from which the solvent has been removed. It includes a stacking step of stacking the cholesteric liquid crystal layer at least once.
Moreover, also in the case of obtaining a laminated body having three or more cholesteric liquid crystal layers, the production method of the present invention can be preferably employed.

[Laminated film]
The laminated film produced by the method for producing a laminated film of the present invention preferably reflects infrared light having a wavelength of 800 nm or more, and reflects 30% or more of incident light in an infrared light region of 800 nm to 2000 nm. More preferably, the wavelength region is reflected. Hereinafter, the laminated film will be described.

(Constitution)
An example of a laminated film produced by the production method of the present invention is shown in FIG.
A laminated film 21 shown in FIG. 1 has a cholesteric liquid crystal layer 14a formed on one surface of a support 12 and having a cholesteric liquid crystal phase fixed. Further, the laminated film 21 shown in FIG. 5 further has cholesteric liquid crystal layers 14b, 16a and 16b formed by fixing the cholesteric liquid crystal phase thereon. The laminated film of the present invention is not limited to these embodiments, and preferably three or more cholesteric liquid crystal layers are formed, and more preferably six or more cholesteric liquid crystal layers are formed. On the other hand, the cholesteric liquid crystal layer may be formed in an odd number layer.

In each of the laminated films 21 shown in FIG. 5, each cholesteric liquid crystal layer is formed by fixing a cholesteric liquid crystal phase. Therefore, light selective reflectivity that reflects light of a specific wavelength based on the helical pitch of the cholesteric liquid crystal phase. Indicates. For example, if the adjacent cholesteric liquid crystal layers (14a and 14b, 16a and 16b) have the same spiral pitch and have opposite optical rotations, left and right circularly polarized light of the same wavelength Both are preferable because they can be reflected. For example, as an example of the laminated film 21 in FIG. 5, of the cholesteric liquid crystal layers 14a and 14b, the cholesteric liquid crystal layer 14a is made of a liquid crystal composition containing a right-turning chiral agent, and the cholesteric liquid crystal layer 14b is left-turning. An example in which the spiral pitch of the cholesteric liquid crystal layers 14a and 14b is approximately equal to d14 nm is provided.
Further, as an example of each of the laminated films 21 in FIG. 5, the relationship between the cholesteric liquid crystal layers 14a and 14b is the same as the above example of the laminated film 21, and the cholesteric liquid crystal layer 16a contains a right-turning chiral agent. An example in which the cholesteric liquid crystal layer 16b is made of a composition and is made of a liquid crystal composition containing a left-rotating chiral agent, the cholesteric liquid crystal layers 16a and 16b have the same helical pitch of d16 nm, and satisfies d14 ≠ d16. Can be mentioned. The laminated film 21 that satisfies this condition exhibits the same effect as the example of the laminated film 21, and further, the wavelength band of the reflected light is expanded by the cholesteric liquid crystal layers 16 a and 16 b, and the broadband light reflectivity is achieved. Indicates.

The laminated film produced by the production method of the present invention exhibits selective reflection characteristics based on the cholesteric liquid crystal phase of each layer. The laminated film of the present invention may have a layer formed by fixing either a right-twisted or left-twisted cholesteric liquid crystal phase. It is preferable to have a layer in which the right-handed and left-handed cholesteric liquid crystal phases having the same helical pitch are fixed, since the selective reflectance for light of a specific wavelength is increased. In addition, it is preferable to have a plurality of pairs of layers in which the right-handed and left-handed cholesteric liquid crystal phases having the same helical pitch are fixed, because the selective reflectance can be increased and the selective reflection wavelength band is widened.
The direction of rotation of the cholesteric liquid crystal phase can be adjusted by the kind of rod-like liquid crystal or the kind of added chiral agent, and the helical pitch can be adjusted by the concentration of these materials.

(Characteristic)
Further, the total thickness when the laminated film is a laminate having two or more cholesteric liquid crystal layers is not particularly limited, but includes four or more cholesteric liquid crystal layers in which a cholesteric liquid crystal phase is fixed, and has a wide light reflection range. In an embodiment exhibiting reflective properties, i.e. heat shielding, the thickness of each layer will be on the order of 3-6 [mu] m and the total thickness d3 of the laminated film will typically be on the order of 15-40 [mu] m.

  The selective reflection wavelength of one cholesteric liquid crystal layer (or each cholesteric liquid crystal layer in the case of having a plurality of cholesteric liquid crystal layers) of the laminated film of the present invention is not particularly limited. By adjusting the helical pitch according to the application, it is possible to provide reflection characteristics with respect to light of a desired wavelength. An example is a so-called infrared reflective film in which at least one layer reflects light in an infrared wavelength region of a wavelength of 800 nm to 2000 nm, thereby exhibiting heat shielding properties. An example of the laminated film of the present invention can reflect sunlight having a wavelength of 900 nm to 1160 nm by 80% or more, and more preferably 90% or more. When a window film is made using this performance, it is possible to achieve a high heat shielding performance with a shielding coefficient defined by JIS A-5759 (film for architectural window glass) of 0.7 or less.

(Membrane strength)
The laminated film of the present invention has good film strength. Particularly when used for windows, the film strength is preferably good.
In the present invention, it is desirable that the film is not damaged by the following method of the laminated film of the present invention. In the present invention, the film strength is measured by the following method.
Using the Gakushin type friction fastness tester AB-301 (Tester Sangyo), place a tresy with a specified amount of weight (500 g) on the laminated film, and rub it for a specified stroke (150 mm) and specified number of times (10 times). Make sure that there are no scratches.

(Form)
The form of the laminated film of the present invention may be a form spread in a sheet form or a form wound in a roll form, but it is also preferable that the film is wound in a roll form. That is, the laminated film of the present invention can maintain good optical characteristics when it is repeatedly wound and delivered in the manufacturing process, and is further stored and transported in a roll-shaped state after manufacturing. It is more preferable that good optical characteristics can be maintained.
Even if the laminated film of the present invention is a self-supporting member which can be used as a window material itself, it is not self-supporting itself and is bonded to a substrate such as a self-supporting glass plate. It may be a member used.

  For example, when the cholesteric liquid crystal phase is fixed, only one of the right and left circularly polarized light components is present in one layer, and the maximum reflection performance is 50%. By repeatedly applying a layer that reflects right-handed circularly polarized light and a layer that reflects left-handed circularly-polarized light, it is possible to improve the reflection performance of up to 100%. The width of the reflection band is usually 100 to 150 nm. However, by using a material having a high birefringence Δn of the cholesteric layer or by giving a concentration distribution of the chiral agent in the cross-sectional direction of the chiral agent inside the produced film. The reflection band can be expanded to about 150 to 300 nm.

(Use)
The use of the laminated film of the present invention is not particularly limited. The laminated film of the present invention is preferably a laminated film for windows.
The laminated film of the present invention may be used by being further bonded to the surface of a glass plate, a plastic substrate or the like. In this aspect, it is preferable that the bonding surface with the glass plate etc. of the said heat-shielding member is adhesiveness. In this embodiment, it is preferable that the laminated | multilayer film of this invention have an adhesion layer, an easily bonding layer, etc. which can be bonded on substrate surfaces, such as a glass plate. Of course, the non-tacky laminated film of the present invention may be bonded to the surface of the glass plate using an adhesive.

The laminated film of the present invention preferably exhibits a heat shielding property against sunlight, and efficiently reflects infrared rays of 700 nm or more of sunlight.
The laminated film of the present invention can be used as a heat-shielding window itself for vehicles or buildings, or as a sheet or film used for windows for vehicles or buildings for the purpose of imparting heat-shielding properties. In addition, it can be used as a freezer showcase, agricultural house material, agricultural reflective sheet, solar cell film, and the like. Among these, it is preferable to use the laminated film of the present invention for a laminated film for windows from the viewpoint of high visible light transmittance and low haze characteristics.

Moreover, the laminated film of the present invention may be incorporated into a laminated glass and used as a heat shielding member.
The heat shielding member is affixed as a heat shielding member for solar radiation on a window of a vehicle such as a house, an office building, or a vehicle. Or it can use for the use as the member for thermal insulation of solar radiation itself (for example, glass for thermal insulation, film for thermal insulation).

The method for producing the laminated glass comprises at least two glass plates, at least two intermediate films, and the laminated film of the present invention: glass plate / intermediate film / multilayer film of the present invention / intermediate film / glass plate. The method includes a step of manufacturing a laminated body that is sequentially laminated and sandwiched between glass plates, and a step of pressure-bonding the laminated body sandwiched between the glass plates while heating. In the process of producing a laminate sandwiched between the glass plates, the laminated film of the present invention includes a support such as a transparent plastic resin film, which improves the film strength of the cholesteric liquid crystal layer and makes it stable. It is preferable from the viewpoint of film formation. However, the laminated body sandwiched between the obtained glass plates may have a structure in which the support does not remain in the laminated film of the present invention, or may have a remaining structure. Among these, the laminated glass sandwiched between the obtained glass plates preferably has a structure in which the support remains in the laminated film of the present invention.
In this specification, the laminate sandwiched between glass plates is a laminate of glass plate / intermediate film / laminated film / intermediate film / glass plate of the present invention in this order, and is pressure-bonded while heating. Say the thing before being done.
The method for producing the laminated glass preferably includes a step of pressure-bonding the laminate sandwiched between the glass plates while heating.
The lamination of the laminate sandwiched between the glass plates and the glass plate is performed by, for example, pre-pressing in a vacuum bag or the like under reduced pressure at a temperature of 80 to 120 ° C. for 30 to 60 minutes, and then in an autoclave. Lamination can be performed at a temperature of 120 to 150 ° C. under a pressure of 0 to 1.5 MPa to obtain a laminated glass in which a laminate is sandwiched between two glasses. Moreover, you may bond together using an adhesive material etc.
At this time, it is preferable that the time of thermocompression bonding at a temperature of 120 to 150 ° C. under a pressure of 1.0 to 1.5 MPa is 20 to 90 minutes.
After the thermocompression bonding, there is no particular limitation on the method of cooling, and the laminated glass body may be obtained by cooling while releasing the pressure as appropriate. In the present invention, it is preferable to lower the temperature while maintaining the pressure after completion of the thermocompression bonding from the viewpoint of further improving the wrinkles and cracks of the obtained laminated glass body. Here, when the temperature is lowered while maintaining the pressure, the pressure inside the apparatus at the time of thermocompression bonding (preferably 130 ° C.) is such that the pressure inside the apparatus at 40 ° C. becomes 75% to 100% at the time of thermocompression bonding. It means to cool down. The method of lowering the temperature while maintaining the pressure is not particularly limited as long as the pressure when the temperature is lowered to 40 ° C. is within the above range, but the pressure inside the pressure device naturally decreases as the temperature decreases. In addition, a mode in which the temperature is lowered without leaking pressure from the inside of the apparatus or a mode in which the temperature is lowered while further pressurizing from outside so that the internal pressure of the apparatus does not decrease as the temperature decreases is preferable. In the case where the temperature is lowered while maintaining the pressure, it is preferable to cool to 120 ° C. to 150 ° C. and then cool to 40 ° C. over 1 to 5 hours.
In the present invention, it is preferable to include a step of releasing the pressure after the temperature is lowered while the pressure is maintained. Specifically, it is preferable to lower the temperature by releasing the pressure after the temperature in the autoclave becomes 40 ° C. or lower after the temperature is lowered while the pressure is maintained.
From the above, the method for producing the laminated glass body includes the step of laminating the first glass, the first intermediate film, the infrared reflective layer, the second intermediate film, and the second glass in this order. Then, it is preferable to include a step of thermocompression bonding at a temperature of 120 to 150 ° C. under a pressure of 1.0 to 1.5 MPa, a step of lowering the temperature while maintaining the pressure, and a step of releasing the pressure.

  Hereinafter, the features of the present invention will be described more specifically with reference to examples and comparative examples (note that comparative examples are not known techniques). The materials, amounts used, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Accordingly, the scope of the present invention should not be construed as being limited by the specific examples shown below.

1. Production of laminated film [Example 1]
(Support)
As the support, a 75 μm thick polyethylene terephthalate film (PET, manufactured by Fuji Film Co., Ltd.) was used.

(Preparation of coating liquid (polymerizable liquid crystal composition))
Coating solutions having the compositions shown in Table 1 and Table 2 below were prepared.

  The coating solutions used for forming each layer are summarized in Table 3 below. The reflection characteristics and reflection wavelength peaks of each layer are also shown.

Using the continuous coating apparatus shown in FIG. 1, the laminated film of Example 1 was produced under the following conditions. The conveyance speed was 10 m / min.
Sending out from the delivery part 31 using a PET film as the support 12;
(A) Using the die coater 33, the thickness of the dry film after drying the coating liquid for the first layer prepared above on one surface of the support 12 is about 4 to 5 μm. Apply at room temperature;
(B) After drying for 30 seconds at room temperature in the drying and aging unit 34, aging is performed for 4 minutes in an atmosphere of 85 ° C. to form a cholesteric liquid crystal phase;
(C) Thereafter, the output is adjusted with an igraphic metal halide lamp at 30 ° C. in the UV irradiation unit 36, and UV irradiation is performed at 500 mJ / cm ² at 30 ° C. and an oxygen concentration of 300 ppm under a nitrogen substitution condition. The first layer (lower layer) of the cholesteric liquid crystal layer 14 b was provided on the support and wound around the winding portion 37.
(D) The wound film is attached to the delivery part 31 and sprayed with 100 ml / m ^{2 of} methyl ethyl ketone as the solvent 41 from the nozzle 42 onto the surface of the wound film on the first cholesteric liquid crystal layer side. ;
(E) The attached solvent 41 was dropped by inertia from a pass roll in which the conveying direction set above the solvent receiver 43 was changed in a different direction, and the solvent 41 was removed. At this time, the time from the attachment of the solvent to the removal of the solvent was 5 seconds.
(F) The coating liquid was changed to the coating liquid for the next layer, and the above (b) to (e) were repeated to form a second cholesteric liquid crystal layer.
The film laminated with the second layer was wound up, and the resulting laminated film was used as the laminated film of Example 1.

Using these, the amount of the orientation control agent on the surface of the first layer before the solvent adhesion step and the amount of the orientation control agent on the surface of the first layer after the solvent removal step are as follows using high performance liquid chromatography: Measured with
<Condition (T)>
The film on which the 20 × 20 cm cholesteric liquid crystal composition is formed is immersed in a predetermined amount of MEK, and the alignment control agent present on the film surface is dissolved in MEK. Using this as a sample solution, using high-performance liquid chromatography, using an eluent (tetrahydrofuran: pure water = 4: 1 (volume ratio)) and measuring a wavelength of 275 nm using an ultraviolet absorptiometer for 40 minutes, the signal obtained The orientation control agent eluting from the area is calculated.
The results are shown in Table 4 below.

[Examples 2 to 4, Comparative Examples 1 to 3]
Laminated films of the respective examples and comparative examples were produced in the same manner as in Example 1 except that the conditions of the UV irradiation process, the solvent adhesion process, and the solvent removal process were changed as shown in Table 4 below.
In Example 2, using the apparatus shown in FIG. 2, a scraping roll 44 having a surface hardness of pencil hardness H was installed above the solvent receiver 43 to scrape off the solvent.
In Example 3, another scraping roll 44 having a size larger than that of Example 2 and having a surface hardness of pencil hardness H is installed using the apparatus shown in FIG. 3, and the scraping roll is used instead of the solvent receiver 43. A methyl ethyl ketone solvent tank 45 for immersing a part of 44 was installed, and the solvent was scraped off.
In Example 4, using the apparatus shown in FIG. 4, a dipping roll 46 was installed instead of the nozzle 42, and the dipping roll 46 was transported over 1 second to adhere the solvent. Thereafter, another scraping roll 44 larger than that in Example 2 was installed, and instead of the solvent receiver 43, a methyl ethyl ketone solvent tank 45 for immersing a part of the scraping roll 44 was installed, and the solvent was scraped off.
In Comparative Example 1, the UV irradiation amount of the first layer was changed to 200 mJ / m ² , and the solvent was not sprayed from the nozzle 42.
In Comparative Example 2, the solvent was not sprayed from the nozzle 42.
In Comparative Example 3, after the solvent adhesion step, only the solvent was volatilized without removing the alignment control agent in the solvent.

2. Evaluation of Laminated Film The film samples of the produced examples and comparative examples were evaluated according to the following items.

(1) Repelling After coating, drying, aging and UV curing of the curable liquid crystal composition of the second layer, the surface state of the obtained sample is confirmed, and the presence or absence of a circular uncoated portion is confirmed in the sample. It was judged.

(2) Film strength As shown in FIG. 6, between two sheet glasses (300 × 350 mm), two polyvinyl butyral (PVB) films (same size as glass), laminated films of each example and comparative example ( Then, the laminated body sandwiched between the obtained glass plates was pre-pressed under vacuum at 95 ° C. for 30 minutes. After preliminary pressure bonding, the laminate sandwiched between the glass plates was laminated while applying heat at 1.3 MPa and 120 ° C. in an autoclave to produce a laminated glass. The obtained laminated glass was an embodiment in which the PET used as the support remained in the laminated film.
The produced laminated glass was visually confirmed, and the film strength was judged based on the presence or absence of breakage.
○: No breakage.
X: There is a break.

  Table 4 below shows the results obtained from these measurements.

From Table 4 above, it was found that the laminated film of the present invention has suppressed repelling and good film strength. In the laminated film of Example 1, cissing was partially observed, but cissing was sufficiently suppressed as compared with other comparative examples, and there was no practical problem.
In Comparative Example 1, it was found that the solvent adhesion step was not performed and the UV irradiation amount was reduced to suppress repellency, and the film strength was insufficient. Comparative Example 2 was an embodiment in which the film adhesion was improved by increasing the UV irradiation amount without performing the solvent adhesion step, and it was found that repelling occurs.

[Reference Example 1]
In Examples 1 to 5, after completion of the thermocompression bonding, the mixture was allowed to cool for about 3 hours while maintaining the pressure, and the pressure was released when the temperature in the autoclave became 40 ° C. or lower. At this time, the pressure before opening was 0.9 MPa.
About the produced laminated glass, when the film crack of the cholesteric liquid crystal layer was evaluated, it turned out that all were further improved rather than Examples 1-5. Moreover, when the reflective nonuniformity of this laminated glass plate was confirmed visually, it turned out that all were further improved rather than Examples 1-5.

DESCRIPTION OF SYMBOLS 10 Support body 12 Support body 14a, 14b, 16a, 16b Cholesteric liquid crystal layer 21 Laminated film 31 Delivery part 33 Die coater 34 Drying and ripening part 36 UV irradiation part 37 Winding part 41 Solvent 42 Nozzle 43 Solvent receiving 44 Scraping roll 45 Solvent tank 46 Roll for immersion

Claims (13)

On the support,
(A) a coating step of applying a curable liquid crystal composition containing a rod-like curable cholesteric liquid crystal compound, an alignment controller and an organic solvent;
(B) An alignment step in which heat is applied to the applied curable liquid crystal composition to align the curable liquid crystal compound to a state of a cholesteric liquid crystal phase;
(C) an irradiation step of irradiating the curable liquid crystal composition with active radiation to form a cholesteric liquid crystal layer in which a cholesteric liquid crystal phase is fixed;
(D) a solvent attachment step of attaching a solvent to the surface of the cholesteric liquid crystal layer;
(E) an alignment control agent removing step of removing the alignment control agent eluted in the solvent attached to the surface of the cholesteric liquid crystal layer;
(F) A laminating step of laminating a cholesteric liquid crystal layer on the cholesteric liquid crystal layer from which the solvent has been removed by repeating the (a) coating step, the (b) alignment step, and the (c) irradiation step at least once. The manufacturing method of the laminated | multilayer film characterized by including.   The method for producing a laminated film according to claim 1, wherein (d) the solvent attaching step is spraying of a solvent with a nozzle.   The method for producing a laminated film according to claim 1, wherein the (d) solvent adhesion step is immersion in a solvent.   The solvent attached to the surface of the cholesteric liquid crystal layer elutes 70% or more of the alignment control agent contained in the curable liquid crystal composition in the coating step (a). The manufacturing method of the laminated | multilayer film as described in any one of 1-3.   The said (d) solvent adhesion process WHEREIN: The same compound as the said organic solvent contained in the curable liquid crystal composition in the said (a) application | coating process is used as the said solvent. A method for producing a laminated film according to one item.   The said solvent used at said (d) solvent adhesion process contains at least 1 sort (s) among cyclohexanone, tetrahydrofuran, cyclohexanol, and methyl ethyl ketone, The laminated | multilayer film as described in any one of Claims 1-5 characterized by the above-mentioned. Production method.   The manufacturing of the laminated film according to any one of claims 1 to 6, wherein (e) the solvent removal step is performed after 5 seconds or more have elapsed since the start of the (d) solvent adhesion step. Method.   The said (e) orientation control agent removal process is scraping off by the roller which coat | covered the material lower than the surface hardness of the said cholesteric liquid crystal layer, The Claim 1 characterized by the above-mentioned. A method for producing a laminated film.   The method for producing a laminated film according to claim 8, further comprising a step of attaching a solvent to the surface of the roller before scraping with the roller.   The method for producing a laminated film according to claim 9, wherein the same compound as the solvent in (d) solvent adhesion is used as the solvent to be adhered to the roller surface.   In the (e) alignment control agent removal step, the amount of the alignment control agent contained in the surface of the cholesteric liquid crystal layer is the amount of the alignment control agent contained in the curable liquid crystal composition in the application step (a). The said solvent is removed so that it may become 10% or less, The manufacturing method of the laminated | multilayer film as described in any one of Claims 1-10:   12. The multilayer according to claim 1, wherein the cholesteric liquid crystal layer includes at least one layer that reflects right circularly polarized light and at least one layer that reflects left circularly polarized light. A method for producing a film.   The method for producing a laminated film according to any one of claims 1 to 12, wherein the cholesteric liquid crystal layer includes at least one layer that reflects infrared light having a wavelength of 800 nm or more.

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