JP2013107333A - Laminated film and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated film that can be wound up without being given damages of a scratch and a wrinkle, etc. to the film surface and the film by excessive contact, sticking of the rear surface and the film surface of the film and the dust at the winding, when the film is wound up, without a black belt is being checked visually on the circumference of the film, nor the tension at the winding is being lowered by preventing the lateral shift in winding without applying the knurling process, and securing a gap between the rear surface and the film surface of the film at winding up, and a method for manufacturing the laminated film.SOLUTION: A first projection pair and a second projection pair that are higher than the central part of the laminated film by 1 μm or more are formed by controlling the forming condition of the coating film by controlling the surface tension, the surface energy, and the drying process in the vicinity of both ends of the width direction side end respectively.

Description

  The present invention relates to a laminated film and a method for producing the same.

  Thin transparent laminated films have been used in recent years for optical reflection members for heat shield members for automobiles and building materials, protective films for polarizing plates for liquid crystal displays, optical compensation films such as retardation plates, plastic substrates, photographic supports, or moving images. Demand has increased for optical materials such as cells, optical filters, and OHP films.

  Such a laminated film can be obtained by forming a film on a transparent base film such as cellulose triacetate (TAC) which serves as a support. The main film formation methods include vacuum film formation methods such as sputtering and plasma CVD, and coating film formation in which a solution in which solvents and various additives are added to the main components such as metals and polymers is applied and dried. Laws are known. In order to perform film formation efficiently and with high productivity by these film formation methods, film formation is continuously performed on a long base film.

  In recent years, there has been a great need for industrial products related to energy conservation due to the growing interest in the environment and energy, and as one of them, it is effective in reducing the heat load of window glass of houses and automobiles, that is, reducing the heat load caused by sunlight. There is a need for glass and film. Such glass and film are required to have a characteristic of transmitting sunlight in the visible light region in the sunlight spectrum and preventing transmission of sunlight in the infrared region.

  As a method for obtaining such heat shielding glass and film characteristics, a method using a cholesteric liquid crystal layer is known. For example, a method is known in which cholesteric liquid crystal layers that function in the near infrared to infrared region and provide circularly polarized light in the same rotational direction are formed on both sides of a λ / 2 plate (for example, Patent Document 1).

  In particular, when manufacturing such a laminated film, as equipment for carrying out the film forming method, a supply roll formed by winding a long base material (film) into a roll shape, and a film-formed base material in a roll shape And a take-up roll wound around. A so-called roll-to-roll film forming apparatus is known. This roll-to-roll film forming apparatus inserts a long base material from a supply roll to a take-up roll into a film forming chamber by a vacuum film forming method or a coating film forming method, The film formation is continuously performed on the substrate to be conveyed in the film formation chamber, while the feeding and the winding of the film-formed base material by the winding roll are performed in synchronization.

  When the film thus formed is wound up, excessive damage or adhesion between the back surface and the film surface of the film at the time of winding may cause damage such as scratches or wrinkles to the film surface or film. There was a problem that the black band was visible on the circumference of the film. On the other hand, when the film is wound at a low tension so as not to cause a problem, the holding of the films is weak and a lateral shift occurs, which may cause a problem as a product.

  In order to avoid such a phenomenon, when winding a plastic film that is continuously conveyed onto a roll, embossing called knurling is used to give micro-projections to both ends of the film so that the lateral displacement during winding is reduced. In addition, it is known to reduce the occurrence of problems due to contact and adhesion by preventing winding tightening and securing a gap between the back surface and the film surface of the film during winding (Patent Documents 2 and 3).

Japanese Patent No. 4109914 Japanese Patent No. 3226190 Japanese Patent Laid-Open No. 2002- 211803

  In order to acquire the said effect, it is necessary to make the height of the convex part formed by knurling larger than the film thickness of a coating film. However, since the height of the convex portion that can be formed by knurling has a limit that affects the thickness and rigidity of the substrate, the above effect cannot be obtained when the film thickness is larger than the convex portion of the knurling. There is a point. In addition, the formed convex portion is often deformed by the pressure after winding, and there is a problem that the above effect cannot be obtained due to variations in height. Furthermore, since a new process is added to form the knurling, there is a problem that productivity is lowered and manufacturing cost is increased.

  As a result of the inventor's earnest study, it was found that when the coating film forming method was used, protrusions were formed at both ends under certain conditions in the base material and the coating liquid. It was also found that this protrusion can be controlled by setting conditions.

  The present invention is for solving the above-mentioned problems, and by controlling the protrusions, it is possible to prevent lateral misalignment and tightening at the time of winding without performing a knurling process, and to prevent the film from being back and filmed at the time of winding. A gap is secured between the film surface and when the film is wound, the film surface or film is damaged by excessive contact or adhesion between the back surface and the film surface of the film during winding, or dust. A laminated film that can be taken up without producing a black belt on the circumference of the film and without lowering the tension during winding, and a method for producing the same For the purpose.

  In order to achieve the above object, a laminated film of the present invention comprises a web-shaped first substrate, a first coating film provided by applying a first coating liquid on the first substrate, and a first coating. A second coating film provided by applying a second coating liquid on a second substrate having a film, wherein the first and second coating films are 1 μm from the center of the laminated film The higher first and second protrusion pairs are formed near both ends of the width direction side end, respectively, and the first protrusion pair is disposed on the side end side of the laminated film rather than the second protrusion pair. Features.

  The first and second coating liquids desirably have a polymer liquid crystal compound, a fluorine-based alignment control agent, and a solvent. Moreover, as for a 1st and 2nd coating film, it is desirable that 90% or more of fluorine of the total fluorine content has segregated on the surface layer from the surface to a depth of 500 nm.

  The difference in height between the first and second protrusion pairs is desirably 3 μm or less. Moreover, it is desirable that the distance between the first and second protrusion pairs is 1 mm or more. The film thickness of the first and second coating films is preferably 1 μm or more. The first and second coating films desirably exhibit a cholesteric phase.

  Moreover, it is desirable that the surface energy of the first and second base materials is 40 mN / m or less. Moreover, it is desirable that the surface tension of the first or second coating liquid is 20 mN / m or more and 40 mN / m or less. The first and second coating films preferably have a viscosity after solvent evaporation of 0.5 Pa · s or less.

  In order to achieve the above object, the method for producing a laminated film of the present invention includes a first coating step in which a first coating liquid is applied to a first coating region on a web-shaped first substrate to obtain a first wet film. A first drying step of evaporating the solvent from the first wet film to obtain a first dry film, a first curing step of curing the first dry film to obtain a first coating film, and a first on the second substrate A second coating step for obtaining a second wet film by applying the second coating liquid to the second coating region inside the coating region, and a second drying step for evaporating the solvent from the second wet film to obtain a second dry film. And a second curing step of curing the second dry film to obtain a second coating film, the surface energy of the first and second base materials is 40 mN / m or less, and the first or second coating liquid The surface tension is 20 mN / m or more and 40 mN / m or less.

  The first and second coating liquids include a polymer liquid crystal compound, a fluorine-based alignment control agent, and a solvent, and the first alignment process, the second drying process, and the first between the first drying process and the first curing process. It is desirable to have a second alignment step between the two curing steps. The first and second coating films desirably exhibit a cholesteric phase. Moreover, it is desirable that the viscosity of the first and second coating liquids after volatilization of the solvent is 0.5 Pa · s or less.

  The distance between the end of the first application area and the end of the second application area is preferably 1 mm or more. The film thickness of the first and second coating films is preferably 1 μm or more.

  In the laminated film of the present invention, the pair of protrusions are formed in the vicinity of both ends of the width direction side end portion of the film, respectively, so that without causing a knurling step, lateral misalignment and winding tightening can be prevented and winding can be performed. Sometimes, a gap can be secured between the back surface and the film surface of the film, so that when the film is wound, the film is exposed to excessive contact or adhesion between the back surface of the film and the film surface during winding, and dust. It can be wound without scratching or wrinkling on the surface or film, without black bands visible on the circumference of the film, and without lowering the tension during winding. it can.

  In the method for producing a laminated film according to the present invention, the pair of ridges are formed near both ends of the width direction side end portion of the film, respectively, and therefore, without performing a knurling step, lateral misalignment and winding tightening can be prevented during winding. Since a gap can be secured between the back surface and the film surface of the film at the time of winding, when the film is wound, excessive contact and adhesion between the back surface of the film and the film surface at the time of winding, dust, Take up the film without damaging the surface or film, such as scratches or wrinkles, or seeing a black belt on the circumference of the film, and without lowering the tension during winding. A laminated film is provided.

It is the schematic explaining the laminated film which concerns on embodiment of this invention. It is a top view which shows the outline of the laminated film manufacturing apparatus of this invention. It is the schematic which shows the coating device used for the coating process of this invention. It is the schematic which shows the coating head used for the coating process of this invention. It is the schematic which shows the drying apparatus used for the drying process of this invention. (A) is sectional drawing in the cross section perpendicular | vertical to the width direction of a film, (B) is sectional drawing in BB 'of (A). It is the schematic which shows the heating apparatus used for the orientation process of this invention. (A) is sectional drawing in the cross section perpendicular | vertical to the width direction of a film, (B) is sectional drawing in CC 'of (A). It is the schematic of the UV irradiation apparatus used for the hardening process of this invention. (A) is sectional drawing in the cross section perpendicular | vertical to the width direction of a film, (B) is sectional drawing in DD 'of (A). It is the schematic explaining the shape change in conditions 1 until a coating liquid turns into a coating film. It is the schematic explaining the shape change until the coating liquid in condition 2 turns into a coating film. It is the schematic explaining the shape change until the coating liquid in condition 3 turns into a coating film. It is the schematic which showed on the map the conditions in which a protrusion pair is formed. It is a graph which shows the result of having analyzed the fluorine of the surface of the 2nd coating film of the laminated film in this invention in the depth direction by ESCA. It is the profile which measured the surface shape of the 1st, 2nd application layer of the laminated film in this invention, and a base film using the film thickness meter.

(Laminated film)
As shown in FIG. 1, the laminated film 2 has a structure in which a first coating layer 11, a second coating layer 12, and a third coating layer 13 are formed on a base film 10, and the width of the laminated film 2. A first pair of ridges 16 and a second pair of ridges 17 are provided near both ends of the direction side end. The laminated film 2 according to the present invention is not limited to the example of FIG. 1, and any form may be used as long as the first protrusion pair 16 and the second protrusion pair 17 are provided in the vicinity of both ends of the width direction end. It does not matter.

  Here, the application layer that causes the first protrusion pair 16 to be formed is referred to as a first application film, and the application layer that forms the second protrusion pair 17 is referred to as a second application film. The coating liquid that is the raw material for the first coating film is the first coating liquid, the coating liquid that is the raw material for the second coating film is the second coating liquid, and the base material before the first coating liquid is applied is the first base material. Let the base material before apply | coating a 2nd coating liquid be a 2nd base material.

  In FIG. 1 (A-1), (A-2), (A-3), the 1st application layer 11 and the 2nd application layer 12 are the 1st and 2nd application films, respectively. Moreover, in FIG. 1 (B-1), (B-2), (B-3), the 1st application layer 11 and the 3rd application layer 13 are the 1st and 2nd application films, respectively. Moreover, in FIG. 1 (C-1), (C-2), (C-3), (C-4), (C-5), and (C-6), the second coating layer 12 and the first coating layer 12 respectively. The three coating layers 13 are the first and second coating films. The laminated film 2 only needs to have the first ridge pair 16 and the second ridge pair 17 in the vicinity of both ends of the end portion in the width direction, and is formed by any other coating layer and other film forming means. The layer may be formed separately.

  In the laminated film 2 shown in FIG. 1, the first protrusion pair 16 and the second protrusion pair 17 in the vicinity of both ends of the end portion in the width direction are at least 1 μm higher than the height near the center of the laminated film 2. It is a feature. Further, the difference in height between the first protrusion pair 16 and the second protrusion pair 17 is preferably 1 μm or less, and the distance between the first protrusion pair 16 and the second protrusion pair 17 is 1 mm or more. It is desirable to be.

  Hereinafter, in order to describe an embodiment using TAC having a surface energy of 40 mN / m for the base film 10, no ridge pair is formed on the first coating layer 11. Therefore, although the form for implementing invention about the laminated film 2 of FIG. 1 (C-1) is described hereafter, about the invention about laminated films 2 other than (C-1) of FIG. It can be implemented by adding. In this case, the first coating layer 11 is a layer that does not have a ridge pair, the second coating layer 12 is a coating layer that causes the first ridge pair 16 to be formed, The coating layer that causes the three coating layers 13 to form the second protrusion pair 17 is the second coating film. Moreover, what applied the 1st application layer 11 to the base film 10 is the 1st base material 11A.

(Laminated film production equipment)
As shown in FIG. 2, the laminated film manufacturing apparatus 20 includes film forming apparatuses 22A, 22B, and 22C. The film forming apparatuses 22A, 22B, and 22C are coating apparatuses 24A, 24B, and 24C, respectively, that apply a coating liquid containing a polymer liquid crystal compound, a fluorine-based alignment control agent, and a solvent to a substrate to form a wet layer. Drying devices 26A, 26B, and 26C for evaporating the solvent from the wet layer to form a dry layer, heating devices 28A, 28B, and 28C for aligning the polymer liquid crystal compound in the dry layer to form the alignment layer, and the alignment layer UV irradiation devices 30A, 30B, and 30C that form a coating layer by irradiation with UV.

  This laminated film manufacturing apparatus 20 is an apparatus for forming a film by roll-to-roll coating, and the belt-like base film 10 is loaded on the supply shaft 32 as a supply roll 34 and formed by coating while being conveyed in the belt-like direction. Is done. The formed laminated film 2 is wound around the winding shaft 36 as a winding roll 38. Further, a transport roller 40 is appropriately provided so that the film can pass through the film forming apparatuses 22A, 22B, and 22C stably.

  As shown in FIGS. 3 and 4, the coating device 24 </ b> B applies the first coating liquid to the first base material 11 </ b> A to form the first wet layer 12 </ b> A, and supplies the coating liquid to the coating head 42. The coating liquid supply tank 44 includes a coating liquid supply line 46 that connects the coating head 42 and the coating liquid supply tank 44. The coating head 42 has a coating supply port 42A for supplying a coating solution from a coating solution supply line 46, a coating slit 42B that is a narrow channel for coating the coating solution uniformly on the substrate, and a coating supply port 42A. An application pocket 42C for temporarily storing the supplied application liquid before supplying it to the application slit 42B is provided. The coating slit 42B is installed at a position close to the base material facing the path side of the base material. Since the coating devices 24A and 24C are the same as the coating device 24B, description thereof is omitted.

  As shown in FIGS. 5A and 5B, the drying device 26B includes a path of the first wet film 12B including the first base material 11A and the first wet layer 12A, and a first coating liquid for the first wet film 12B. A hot-air device 48 that applies hot air to the side coated with sucrose is installed, and a solvent recovery device 50 that recovers the solvent is provided below. In addition, a controller (not shown) that adjusts the environment such as temperature and humidity is provided in the drying device 26B, so that the first wetting layer is dried to form an optimum environment for the first winding. It has been adjusted. The first dry film 12C is sent out from the drying device 26B. Since the drying devices 26A and 26C are the same as the drying device 26B, description thereof is omitted.

  As shown in FIGS. 6A and 6B, the heating device 28B is provided with a path for the first dry film 12C and a heater 52 for heating the first dry film 12C from the thickness direction. The heating device 28B is provided with a controller (not shown) for adjusting the environment such as temperature and humidity, and the first liquid crystal compound is aligned in the first dry layer to form the first alignment layer. It is adjusted to the optimal environment. The first alignment film 12D is sent out from the heating device 28B. Since the heating devices 28A and 28C are the same as the heating device 28B, description thereof is omitted.

  As shown in FIGS. 7A and 7B, the UV irradiation device 30B includes a UV irradiation lamp that irradiates UV on the path of the first alignment film 12D and the side of the first alignment film 12D to which the first coating liquid is applied. 54 is installed. In addition, a controller (not shown) for adjusting the environment such as temperature and humidity is provided in the UV irradiation apparatus 30B, which is an optimal environment for curing the first alignment layer and forming the first coating film. It has been adjusted. The first cured film 12E is sent out from the heating device 28B. Since the UV irradiation apparatuses 30A and 30C are the same as the UV irradiation apparatus 30B, description thereof is omitted.

(Coating solution)
In the present invention, each of the coating liquids forming the first coating layer 11 to the third coating layer 13 has one or more polymerizable liquid crystal compounds, an alignment controller, a polymerization initiator, a chiral agent, and a solvent. In each case, the following compounds can be used.

  In the present invention, a rod-like curable cholesteric liquid crystal compound such as a rod-like nematic liquid crystal compound is used as the polymerizable liquid crystal compound. For example, azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, alkoxy-substituted phenylpyrimidines, phenyldioxanes, Tolanes and alkenylcyclohexylbenzonitriles are used.

  A polymerizable cholesteric liquid crystal compound obtained by introducing a polymerizable group into the cholesteric liquid crystal compound can also be used. Examples of the polymerizable group include an unsaturated polymerizable group, an epoxy group, and an aziridinyl group. Among them, an unsaturated polymerizable group is preferable, and an ethylenically unsaturated polymerizable group is particularly preferable. 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. 5,622,648, US Pat. No. 5,770,107, International Publication WO95 / 22586. 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, and two or more kinds of polymerizable cholesteric liquid crystal compounds may be used in combination.

  The temperature range in which these polymerizable liquid crystal compounds become a cholesteric phase is 20 ° C to 150 ° C. Therefore, conditions such as the hot air device 48 can be set in a range where the temperature in the drying devices 26A, 26B, and 26C does not exceed the upper limit of the temperature at which the cholesteric phase is reached. In the present embodiment, the temperature in the heating process is set to 85 degrees.

  In the present invention, compounds such as those described in paragraphs 0016 to 0050 of JP-A-2005-099248 are used as the alignment control agent. For example, the compound described in Chemical formula 1 is used. In addition, it is not restrict | limited to these compounds, Moreover, the compound which has the function similar to these may be used independently, and 2 or more types may be used together.

In the present invention, in the embodiment in which the polymerization reaction proceeds by ultraviolet irradiation, the polymerization initiator to be used is preferably a photopolymerization initiator that can start the polymerization reaction by ultraviolet irradiation. For example, α-carbonyl compounds (described in US Pat. Nos. 2,367,661 and 2,367,670), acyloin ethers (described in US Pat. No. 2,448,828), α-hydrocarbon substituted aromatic acyloin compounds (US Pat. 2722512 description), polynuclear quinone compounds (described in US Pat. Nos. 3,046,127 and 2,951,758), a combination of triarylimidazole dimer and p-aminophenyl ketone (described in US Pat. No. 3,549,367) , Acridine and phenazine compounds (JP-A-60-105667, U.S. Pat. No. 4,239,850) and oxadiazole compounds (U.S. Pat. No. 4,221,970) are used. In addition, it is not restrict | limited to these compounds, Moreover, the compound which has the function similar to these may be used independently, and 2 or more types may be used together.

  In the present invention, a horizontal alignment agent as described in paragraphs 0057 to 0096 of JP-A-2002-179668 is used as the chiral agent. For example, the compound described in Chemical formula 2 is used. In addition, it is not restrict | limited to these compounds, Moreover, the compound which has the function similar to these may be used independently, and 2 or more types may be used together.

  In the present invention, the solvent is not particularly limited, and a known solvent that dissolves the curable cholesteric liquid crystal compound 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) and the like. In addition, it is not restrict | limited to these compounds, Moreover, the compound which has the function similar to these may be used independently, and 2 or more types may be used together.

(Mechanism for formation of ridges)
Below, the formation mechanism of the shape of the 1st wet layer 12A at the time of apply | coating the 1st wet layer 12A on 11 A of 1st base materials is demonstrated. The shape of the first wetting layer 12A is determined so that the energy E expressed by Equation 1 is minimized. The interface energy between the first substrate 11A per unit area and the atmosphere is referred to as the surface energy of the first substrate 11A, and the interface energy between the first wetting layer 12A per unit area and the atmosphere is defined as the first wetting layer 12A. This is referred to as surface tension. The terms surface energy and surface tension are defined similarly.

  The first term and the second term in Equation 1 indicate the amount of interfacial energy between the first base material 11A and the atmosphere, and between the first base material 11A and the first wet layer 12A, respectively. The fourth term shows the interfacial energy between the first wet layer 12A and the atmosphere and the gravitational potential energy of the first wet layer 12A, respectively. From Equation 1, it can be said that the factor that determines the system is composed of three interface energies and gravitational potential energy.

  Since the sum of the area where the first substrate 11A and the atmosphere are in contact with each other and the area where the first substrate 11A and the first wetting layer 12A are in contact with each other is a constant value regardless of the shape of the first wetting layer 12A. Is established.

  Thus, the energy E can be divided into two as follows and can be considered as Expression 3 and Expression 4.

  Considering Equation 2, it can be seen that in Equation 3, elements such as the wetting angle contribute to the determination of the shape of the first wetting layer 12A. Accordingly, hereinafter, a system having a wetting angle greater than 90 degrees is A, a system having a 90 degree system is B, and a system having a wetting angle smaller than 90 degrees is C.

  Therefore, it can be understood that E2 in Formula 4 should be considered for elements of the shape of the first wet layer 12A other than the wetting angle. Therefore, the process of determining the shape of the first wet layer 12A will be described under the conditions shown in the following formulas 5 to 7.

  A process for determining the shape of the first wetting layer 12A under the condition of Expression 5 will be described with reference to FIG. From the condition of Equation 5, the shape immediately after application of the first wet layer 12A is determined so as to minimize the interface energy between the first wet layer 12A and the atmosphere. That is, it is determined so as to minimize the contact area between the first wet layer 12A and the atmosphere. Therefore, the shape immediately after the application of the first wetting layer 12A is shown in FIGS. 8A-1 and 8B-B in a system with a wetting angle greater than 90 degrees, a system with 90 degrees, and a system with less than 90 degrees, respectively. 1) and as shown in FIG.

  Since the area where the both end portions of the first wet layer 12A are in contact with the outside air is the largest, the solvent is efficiently blown off, so that both end portions of the first wet layer 12A are easily dried. Therefore, in each of FIG. 8 (A-1), FIG. 8 (B-1), and FIG. 8 (C-1), FIG. 8 (A-2), FIG. 8 (B-2), and FIG. As shown in each of 2), the first initial dry region 12AS is formed at both ends of the first wet layer 12A.

  When the first initial drying region 12AS is formed, the first wetting layer 12A forms an appropriate wetting angle not only with respect to the first base material 11A but also with respect to the first initial drying region 12AS. The shape may be changed so that the energy E shown in FIG. However, according to the condition of Equation 5, since the contact area between the first wet layer 12A and the atmosphere is determined to be minimum, FIG. 8 (A-3), FIG. 8 (B-3), As shown in each of FIGS. 8C-3, it can be seen that the shape of the first wet layer 12A substantially does not change. In other words, it can be said that no ridge pair is formed in the condition of Expression 5.

  The process for determining the shape of the first wetting layer 12A under the condition of Equation 6 will be described with reference to FIG. From the condition of Equation 6, the shape immediately after application of the first wet layer 12A is determined so as to minimize the gravitational potential energy of the first wet layer 12A. Therefore, the shape immediately after the application of the first wetting layer 12A is shown in FIGS. 9A-1 and 9B-B in a system with a wetting angle greater than 90 degrees, a system with 90 degrees, and a system with less than 90 degrees, respectively. 1) As shown in FIG. 9 (C-1), the shape becomes extremely wet and spread.

  Since the area where the both end portions of the first wet layer 12A are in contact with the outside air is the largest, the solvent is efficiently blown off, so that both end portions of the first wet layer 12A are easily dried. Therefore, in each of FIG. 9 (A-1), FIG. 9 (B-1), and FIG. 9 (C-1), FIG. 9 (A-2), FIG. 9 (B-2), and FIG. As shown in each of 2), the first initial dry region 12AS is formed at both ends of the first wet layer 12A.

  When the first initial drying region 12AS is formed, the first wetting layer 12A forms an appropriate wetting angle not only with respect to the first base material 11A but also with respect to the first initial drying region 12AS. The shape may be changed so that the energy E shown in FIG. However, according to the condition of Equation 6, since it is determined to minimize the gravitational potential energy of the first wet layer 12A, FIG. 9 (A-3), FIG. 9 (B-3), FIG. As shown in each of (C-3), it turns out that the shape of 12 A of 1st wet layers substantially does not change. In other words, it can be said that no ridge pair is formed in the condition of Expression 6.

  A process for determining the shape of the first wetting layer 12A under the condition of Expression 7 will be described with reference to FIG. From the condition of Equation 7, the shape immediately after the application of the first wet layer 12A tends to minimize the contact area between the first wet layer 12A and the atmosphere, and the gravitational potential energy of the first wet layer 12A is minimized. The energy E in Equation 1 is determined to be minimized by the balance with the tendency to try. Therefore, the shapes immediately after the application of the first wetting layer 12A are shown in FIGS. 10A-1 and 10B-B in a system with a wetting angle greater than 90 degrees, a system with 90 degrees, and a system with less than 90 degrees, respectively. 1) As shown in FIG. 10C-1, the shape is intermediate between the condition of Expression 5 and the condition of Expression 6.

  Since the area where the both end portions of the first wet layer 12A are in contact with the outside air is the largest, the solvent is efficiently blown off, so that both end portions of the first wet layer 12A are easily dried. Therefore, in each of FIG. 10 (A-1), FIG. 10 (B-1), and FIG. 10 (C-1), FIG. 10 (A-2), FIG. 10 (B-2), FIG. As shown in each of 2), the first initial dry region 12AS is formed at both ends of the first wet layer 12A.

  When the first initial drying region 12AS is formed, the first wetting layer 12A forms an appropriate wetting angle not only with respect to the first base material 11A but also with respect to the first initial drying region 12AS. The shape may be changed so that the energy E shown in FIG. Since the wetting angle between the first wetting layer 12A and the first initial drying region 12AS is substantially 0 degrees, the energy in Formula 1 is balanced by the tendency to minimize the gravitational potential energy of the first wetting layer 12A. Since the solution for minimizing E changes, as shown in FIGS. 10A-3, 10B-3, and 10C-3, the shape of the first wetting layer 12A is shown. Changes under the influence of the first initial drying region 12AS. As a result, a ridge pair is formed. That is, it can be said that the ridge pair is formed only in the condition of Expression 7. In particular, the conditions (B-1), (B-2), and (B-3) in FIG. 10 are conditions under which the protrusion pairs are generated in a substantially vertical direction.

  As shown in FIG. 11, in the present invention, a system using a polymer liquid crystal compound, a fluorine-based alignment control agent, and a solvent approximately satisfies the conditions of the region 58. Of these, when the conditions of the region 60 are satisfied, that is, when the conditions of FIGS. 10B-1, B-2, and B-3 are satisfied, the pair of protrusions is generated in a substantially vertical direction. It is the most preferable condition for carrying out the present invention. Therefore, in the region 58, by designing the surface energy of the first base material 11A as small as possible, the condition shifts according to the arrow 62, and a pair of ridges is likely to be generated in a substantially vertical direction. Similarly, by designing the surface tension of the first wetting layer 12A as large as possible, the conditions shift according to the arrow 64, and the pair of ridges are likely to be generated in the substantially vertical direction. Moreover, the height of the protrusion pair can be increased by increasing the film thickness of the first wet layer 12A. Although the mechanism for determining the shape of the first wetting layer 12A on the first base material 11A has been described here, the present invention is not limited to this, but can be applied to the shape determination of the wetting layer on all the base materials.

  Next, the operation of the present invention will be described. As shown in FIG. 2, in the laminated film manufacturing apparatus 20, the first coating layer is respectively applied to the base film 10 supplied from the supply roll 34 loaded on the supply shaft 32 by the film forming apparatuses 22A, 22B, and 22C. 11, the second coating layer 12, and the third coating layer 13 are sequentially formed, and the formed laminated film 2 is wound around the winding shaft 36 as a winding roll 38. Hereinafter, although formation of the 2nd application layer 12 which is a 1st application film is described in detail, since formation of the 1st application layer 11 and the 3rd application layer 13 is made by a substantially equivalent process, explanation is omitted.

  As shown in FIGS. 3 and 4, in the coating apparatus 24 </ b> B, the first base material 11 </ b> A supplied from the film forming apparatus 22 </ b> A is supplied from the coating liquid supply tank 44 through the coating liquid supply line 46 to the coating supply port 42 </ b> A. The first coating liquid supplied to the coating head 42 is temporarily stored in the coating pocket 42C and applied from the coating slit, whereby the first wet layer 12A is formed.

  As shown in FIG. 5, in the first wet film 12 </ b> B in which the first wet layer 12 </ b> A is applied on the first base material 11 </ b> A, it is contained in the first wet film 12 </ b> A from the hot air device 48 provided in the drying device 26 </ b> B. The solvent evaporates to obtain the first dry film 12C. At the same time, the solvent is recovered by the adsorption recovery device 50 and reused.

  Since the area where the both end portions of the first wet layer 12A are in contact with the outside air is the largest, the solvent is efficiently blown off, so that both end portions of the first wet layer 12A are easily dried. Therefore, by designing the surface energy of the first base material 11A and the surface tension of the first wet layer 12A so as to satisfy the condition of Expression 7, and adjusting the drying conditions of the drying device 26B, FIG. 10 (B-3) It is possible to obtain the 1st dry film 12C which has the 1st dry layer of the shape which has the 1st protrusion pair 16 requested | required of the laminated | multilayer film based on this invention as shown in FIG.

  When using a coating liquid having a polymer liquid crystal compound, a fluorine-based alignment controller, and a solvent, the surface energy of the substrate is 40 mN / m or less, and the surface tension of the coating liquid is 20 mN / m or more and 40 mN / m or less. Therefore, the system satisfies the conditions of FIGS. 10 (B-1), (B-2), and (B-3). Therefore, when forming a coating layer having a pair of ridges, for example, in this embodiment, the second coating layer 12 and the third coating layer 13 are formed under such conditions, and a coating without a pair of ridges is formed. In the case of forming a layer, for example, in the present embodiment, it is necessary to form a film on the first coating layer 11 under a condition that does not satisfy this.

  In addition, when using a coating liquid containing a polymer liquid crystal compound, a fluorine alignment control agent, and a solvent, the organic compound used for the fluorine alignment control agent has a lower surface tension than other organic substances not containing fluorine. Therefore, fluorine is unevenly distributed near the surface. For this reason, when using a fluorine-type orientation control agent, it becomes easy to control a protrusion pair. In addition, since the fluorine-based organic material is softer than the organic material not containing fluorine (for example, when the Rockwell hardness test is conducted under the test conditions of scale R, polytetrafluoroethylene is about 58, polyfluorinated ethylene propylene The first and second protrusion pairs 16 and 17 have a structure that is slightly softer than the back side of the base film 10. For this reason, when the film is wound, excessive damage or contact between the back surface and the film surface of the film at the time of winding may cause damage such as scratches or wrinkles to the film surface or film, The film can be wound without a black belt being visually recognized on the circumference of the film and without lowering the tension during winding.

  As shown in FIG. 6, in the first dry film 12C that has passed through the drying device 26B, the polymer liquid crystal compound contained in the first dry layer becomes a cholesteric liquid crystal layer by the heater 52 provided in the heating device 28B. Oriented. Since the heating device 28B is designed so that a temperature difference hardly occurs in the film width direction, it is suitable for orientation. This alignment condition is adjusted so as to be a cholesteric liquid crystal layer having the characteristic of preventing the transmission of infrared rays in the infrared region according to each material, so that the first alignment layer having the first characteristic layer having a desired characteristic is obtained. An oriented film 12D is obtained. In the case where a polymer liquid crystal compound is not used for the coating liquid, this alignment step by the heating device 28B is not necessary.

  Moreover, it is desirable that the viscosity of the coating solution after evaporation of the solvent is 0.5 Pa · s or less. In this case, the viscosity decreases at the temperature in the heating device 28B, the first dry layer flows to the first base material 11A in a delicate manner, and the height of the protrusion pair increases. is there.

  As shown in FIG. 7, in the first alignment film 12D that has passed through the heating device 28B, UV irradiation is performed from the upper part of the film by the UV irradiation device 30B, the first alignment layer is cured, and the first alignment layer 11A is set on the first substrate 11A. A second coating layer 12 is formed. Thereby, the 1st cured film 12E is obtained.

  Similarly to the second coating layer 11, the first coating layer 11 and the third coating layer 13 are formed by the film forming apparatuses 22A and 22C. As for the 1st application layer 11, the 2nd application layer 12, and the 3rd application layer 13, it is desirable that the thickness is 1 micrometer or more. In this case, it has the characteristic of preventing the transmission of sunlight in the infrared region. In addition, it is desirable that the difference in height between the first or second protrusion pair is 3 μm or less, and the distance between them is 1 mm or more. In these cases, the shape of the first or second protrusion pair becomes a shape that can prevent a lateral shift and winding tightening at the time of winding and can secure a gap between the back surface and the film surface of the film at the time of winding. The film surface or film may be damaged or wrinkled by contact or adhesion between the back surface and the film surface of the film, dust adhering to the film, lateral displacement or tightening, or on the circumference of the film The film can be wound so that the black band is not visually recognized.

  In the thus obtained laminated film 2 as shown in FIG. 1 (C-1), the surface of the second coating film 13 is several nm with argon ions by ESCA (Electron Spectroscopy for Chemical Analysis, X-ray photoelectron spectroscopy). / Min. When the elemental analysis in the thickness direction was performed at the etching rate, the calculation result of fluorine as shown in FIG. 12 was obtained. As shown in FIG. 12, it was found that 90% or more of the total fluorine content was segregated on the surface layer from the surface of the second coating film 13 to a depth of 500 nm. Moreover, in the same laminated | multilayer film 2, when the shape was measured using the film thickness meter in the one side of the edge part which has a pair of protrusions, the profile as shown in FIG. 13 was obtained. Note that not only the second coating film 13 but also all the coating layers using a fluorine-based orientation control agent showed substantially the same tendency of segregation of fluorine.

  In the present embodiment, the first coating layer 11 is a layer having no pair of ridges, and the coating layer that causes the second coating layer 12 to form the first pair of ridges 16 is the first coating film. Yes, the coating layer that causes the third coating layer 13 to form the second protrusion pair 17 is the second coating film, but is not limited thereto, and the first coating layer 11 and the second coating layer are not limited thereto. It is sufficient that the protrusion pairs are formed in any two of the films 12 and 13 and the combination thereof may be any combination as shown in FIG. However, when the 1st application layer 11 is used as a 1st application film, it is necessary to select the surface energy of the base film 10 used as a 1st base material smaller than 40 mN / m.

  Moreover, the coating width of the 1st coating layer 11, the 2nd coating layer 12, and the 3rd coating layer 13 is as shown in FIG. 1 (A-1) (B-1) (C-1), for example. The first coating layer 11, the second coating layer 12, and the third coating layer 13 are desirable in descending order. This is because it is easy to control the first and second pair of ribs.

  In this embodiment, although the form which consists of the base film 10 and the three coating layers 11, 12, and 13 was demonstrated, this invention is not restricted to this, A coating layer may be only two layers, For example, even if the number of coating layers is increased so that the surface energy condition of the base material is advantageous so that a pair of ridges can be easily formed, and the total number of coating layers is four or more, the laminated film 2 has two ridge pairs wide. Any structure may be used as long as it has a directional side end. Further, for example, any layer formed by a vacuum film forming process or the like may be provided on the base film 10 or each coating layer for the same purpose as that of four or more coating layers. Moreover, in this embodiment, in order to make the film a laminated film for heat shielding, as shown in the following examples, two right circularly polarized reflective layers and one left circularly polarized reflective layer were provided. A coating layer may be added as appropriate for the purpose of improving the reflection characteristics.

  Next, examples of the present invention will be described. 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.

In this example and this comparative example, the first coating layer 11, the second coating layer 12, and the third coating layer 13 were formed on the base film 10 under various conditions to obtain a laminated film. Was taken up by the take-up shaft 36, and the situation at that time was evaluated according to the following criteria.
1. Winding evaluation ○: No winding shape deformation Δ: Partial winding shape deformation ×: Overall winding shape deformation Horizontal misalignment evaluation ○: No lateral misalignment △: Partial lateral misalignment ×: Overall lateral misalignment

In Examples and Comparative Examples, a polyethylene terephthalate film (PET, manufactured by Fuji Film Co., Ltd.) having a thickness of 75 μm was used as the base film 10. In all the examples and comparative examples, the film conveyance speed was 10 m / min, the drying time in the drying process was 30 seconds, the heating temperature in the heating process was 85 degrees, and the heating time was 4 minutes. Also, in the UV irradiation process, the atmosphere inside the apparatus is replaced with nitrogen, the oxygen concentration is set to 300 ppm, the temperature is set to 30 ° C., the output is adjusted with an igraphic metal halide lamp, and the UV irradiation is performed at 500 mJ / cm ^2. The alignment phase of the polymer liquid crystal compound was cured.

  Moreover, the coating liquid (A) and coating liquid (B) which have a polymer liquid crystal compound, a fluorine-type orientation control agent, and a solvent were used with respect to all the coating layers. The compositions of the coating liquid (A) and the coating liquid (B) are the compositions shown in Table 1 and Table 2, respectively.

  Table 3 below shows combinations of coating solutions used for forming each coating layer. Table 3 also shows the reflection characteristics and reflection wavelength peaks of each layer.

  The implementation conditions and evaluation results of this example are shown in Table 4, and the implementation conditions and evaluation results of this comparative example are shown in Table 5.

  As shown in Table 4, for the laminated film 2 having the first and second protrusion pairs 16 and 17 having a height of 1 μm or more and a height difference of 3 μm or less, both winding evaluation and lateral deviation evaluation are performed. Good results were obtained. On the other hand, as shown in Table 5, in the laminated film having only the first protrusion pair having a height of 1 μm or more, reasonable results were obtained in both the winding evaluation and the lateral deviation evaluation. In the laminated film having a pair of protrusions having a height of 1 μm or more, a reasonable result was obtained in the winding evaluation, and a bad result was obtained in the lateral deviation evaluation.

  From this, it turned out that the laminated film 2 which has the 1st and 2nd protrusion pair 16, 17 whose height is 1 micrometer or more and whose height difference is 3 micrometers or less is an invention which solves this subject. It was also found that when the surface energy of the substrate is 40 mN / m or less and the surface tension of the coating solution is 20 mN / m or more and 40 mN / m or less, the ridge pair is easily formed.

2 Laminated Film 10 Base Film 11 First Application Layer 11A First Base Material 12 Second Application Layer 12A First Wet Layer 12B First Wet Film 12C First Dry Film 12D First Oriented Film 12E First Cured Film 12AS First Initial drying region 13 Third coating layer 16 First protrusion pair 17 Second protrusion pair 20 Laminated film manufacturing apparatus 22A, 22B, 22C Film forming apparatus 24A, 24B, 24C Coating apparatus 26A, 26B, 26C Drying apparatus 28A, 28B , 28C Heating device 30A, 30B, 30C UV irradiation device

Claims (16)

A web-like first substrate;
A first coating film provided by applying a first coating liquid on the first substrate;
A second coating film provided by applying a second coating liquid on the second substrate having the first coating film;
A laminated film comprising:
The first and second coating films have first and second protrusion pairs that are 1 μm or more higher than the center portion of the laminated film, and are formed in the vicinity of both ends of the width direction side ends, respectively.
The laminated film according to claim 1, wherein the pair of first protrusions is disposed closer to the side end of the laminated film than the pair of second protrusions.   The laminated film according to claim 1, wherein the first and second coating liquids include a polymer liquid crystal compound, a fluorine-based alignment control agent, and a solvent.   The laminated film according to claim 2, wherein the first and second coating films have a segregation of fluorine of 90% or more of the total fluorine content on the surface layer from the surface to a depth of 500 nm.   The laminated film according to any one of claims 1 to 3, wherein a difference in height between the first and second protrusion pairs is 3 m or less.   The laminated film according to any one of claims 1 to 4, wherein a distance between the first and second protrusion pairs is 1 mm or more.   The laminated film according to claim 1, wherein the first and second coating films have a thickness of 1 μm or more.   The laminated film according to claim 2, wherein the first and second coating films exhibit a cholesteric phase.   The surface energy of said 1st and 2nd base material is 40 mN / m or less, The laminated | multilayer film as described in any one of Claims 1-7 characterized by the above-mentioned.   The surface tension of said 1st or 2nd coating liquid is 20 mN / m or more and 40 mN / m or less, The laminated film as described in any one of Claims 1-8 characterized by the above-mentioned.   The laminated film according to claim 1, wherein the first and second coating liquids have a viscosity after solvent evaporation of 0.5 Pa · s or less. A first coating step of applying a first coating solution to a first coating region on a web-shaped first substrate to obtain a first wet film;
A first drying step of obtaining a first dry film by evaporating the solvent from the first wet film;
A first curing step for curing the first dry film to obtain a first coating film;
A second application step of obtaining a second wet film by applying a second application liquid to the second application area inside the first application area on the second substrate;
A second drying step of obtaining a second dry film by evaporating the solvent from the second wet film; a second curing step of obtaining a second coating film by curing the second dry film;
Have
The surface energy of the first and second substrates is 40 mN / m or less,
The surface tension of said 1st or 2nd coating liquid is 20 mN / m or more and 40 mN / m or less, The manufacturing method of a laminated film characterized by the above-mentioned. The first and second coating liquids have a polymer liquid crystal compound, a fluorine-based alignment control agent, and a solvent,
A first orientation step between the first drying step and the first curing step;
A second orientation step between the second drying step and the second curing step;
The manufacturing method of the laminated | multilayer film of Claim 11 characterized by having.   The method for producing a laminated film according to claim 12, wherein the first and second coating films exhibit a cholesteric phase.   The method for producing a laminated film according to any one of claims 11 to 13, wherein the first and second coating liquids have a viscosity after solvent volatilization of 0.5 Pa · s or less.   The method for producing a laminated film according to claim 11, wherein an interval between an end portion of the first application region and an end portion of the second application region is 1 mm or more.   The method for producing a laminated film according to any one of claims 11 to 15, wherein the film thickness of the first and second coating films is 1 µm or more.

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