WO2016208548A1

WO2016208548A1 - Optical film and optical laminate containing same

Info

Publication number: WO2016208548A1
Application number: PCT/JP2016/068305
Authority: WO
Inventors: 陽明森田
Original assignee: コニカミノルタ株式会社
Priority date: 2015-06-25
Filing date: 2016-06-20
Publication date: 2016-12-29
Also published as: JPWO2016208548A1; CN107710035B; CN107710035A; JP6729580B2

Abstract

The present invention provides a means for suppressing the occurrence of wrinkles in the processing step of an optical film, even if there is a significant difference in the high-temperature properties of the substrate and reflective layer of the optical film.　The present invention pertains to an optical film having a substrate and a reflective layer, wherein the substrate and the reflective layer have an absolute value for the difference in storage modulus (E') at 150°C (measurement conditions: conforming with JIS K7244 - 1:1998, tensile mode, heating rate 5°C/min, frequency 10Hz) is at least 0.05GPa, and the loss tangent (tanδ) at 150°C) (measurement conditions: conforming with JIS K7244-1:1998, tensile mode, heating rate 5°C/min, frequency 10Hz) is 0.12-0.20.

Description

Optical film and optical laminate including the same

The present invention relates to an optical film and an optical laminate including the same. In more detail, this invention relates to the technique for suppressing generation | occurrence | production of the wrinkle of an optical film at the time of processing an optical film for optical laminated body formation.

In recent years, optical films for the purpose of transmitting or reflecting and absorbing light in a specific wavelength range, or bonding to windows of automobiles and buildings, etc., for the purpose of heat insulation, light shielding, and prevention of scattered fragments when damaged Is being used. Such an optical film has, for example, an infrared shielding ability that suppresses intrusion of infrared rays and prevents an excessive increase in temperature in a building or in a vehicle, thereby reducing the use of cooling and achieving energy saving. Especially useful. As a film having such optical shielding characteristics, a dielectric multilayer film in which layers having different refractive indexes are laminated is known. The dielectric multilayer film functions as a reflective layer, and has an advantage that the spectral reflectance can be freely set by using interference of reflected light from the boundary of the layers. From this, as the said optical film, it is bonded and used for the window etc. of a building, and is the said optical film between a pair of glass substrates which is one of the optical laminated bodies using the said optical film. Laminated glass is distributed in the market.

Here, the optical film is generally processed by applying heat and load when forming the optical laminate, but in the conventional optical film, wrinkles are generated in this processing step. Was a problem. Generation | occurrence | production of the wrinkle in a process process will cause the fall of the optical performance accompanying film deformation not only to impair the external appearance of an optical laminated body. Therefore, in order to solve such a problem, the thermal shrinkage rate of the optical film is increased, and the optical film is deformed according to the shape of the substrate in the optical laminated body or the glass plate of the laminated glass, thereby removing the excess portion of the optical film. There has been proposed a technique for reducing wrinkles in the machining process.

For example, in Japanese translations of PCT publication No. 2004-503402 (corresponding to WO 2001/096107), a birefringent dielectric multilayer film is sufficiently provided so as not to substantially generate wrinkles with respect to a substrate having a complex curvature. Disclosed is a method for producing a laminated article, including a step of heat setting so that the film can be shrunk, and a birefringent dielectric multilayer film used therefor.

Further, for example, in Japanese Patent Application Laid-Open No. 2010-265161 (corresponding to WO 2010/119770), a laminated glass having two resin intermediate films and a plastic film with an infrared reflecting film between two curved glass plates. A manufacturing method is disclosed. More specifically, the shape of the plastic film with the infrared reflective film and the size with respect to the glass plate before the two resin intermediate films or between the plastic film with the infrared reflective film and the resin intermediate film are heat-sealed appropriately. The selection is disclosed. Furthermore, Japanese Patent Application Laid-Open No. 2010-265161 discloses that the thermal shrinkage rate of the plastic film with an infrared reflecting film is set to a predetermined value or more.

Here, the present inventors paid attention to the fact that in the prior art, the generation of wrinkles in the processing step may not be sufficiently suppressed depending on the optical film. The present inventors have found that the optical film having the base material and the reflective layer, and the high-temperature physical properties of the base material and the reflective layer are greatly different, can be wrinkled only by increasing the thermal shrinkage rate of the optical film. It was found that it cannot be sufficiently suppressed.

Therefore, the present invention has been made in view of the above problems, and means capable of sufficiently suppressing the occurrence of wrinkles in the optical film processing step even when the high-temperature physical properties of the optical film substrate and the reflective layer are greatly different. The purpose is to provide.

In view of the above-mentioned problems, the present inventors proceeded with intensive studies. As a result, the present inventors have found that the above problem can be solved by setting the loss coefficient (tan δ) at 150 ° C. of the optical film to a value within a predetermined range, and completed the present invention.

That is, the above-mentioned problem of the present invention is solved by the following means.

A substrate, and a reflective layer;
The base material and the reflective layer have an absolute value of a difference in storage elastic modulus (E ′) at 150 ° C. (measuring condition: JIS K7244-1: 1998, tensile mode, heating rate 5 ° C./min, frequency 10 Hz). Is 0.05 GPa or more,
Loss coefficient at 150 ° C. (tan δ) (measurement conditions: JIS K7244-1: 1998 compliant, tensile mode, temperature rising rate 5 ° C./min, frequency 10 Hz) is 0.12 to 0.20.
Optical film.

It is a schematic sectional drawing which shows an example of the optical laminated body containing the optical film which concerns on one form of this invention. Here, 10 is an optical laminate, 11 is a substrate having a curved surface on the outdoor side, 12 and 14 are intermediate layers, 13 is an optical film according to an embodiment of the present invention, and 15 is a curved surface on the indoor side. Each substrate is represented. Moreover, 13a represents the base material of the optical film which concerns on one form of this invention, 13b represents the reflection layer of the optical film which concerns on one form of this invention, respectively. It is a schematic sectional drawing which shows another example of the optical laminated body containing the optical film of this invention. Here, 20 represents an optical laminate, 21 represents a substrate having a curved surface, 22 represents an intermediate layer, and 23 represents an optical film according to an embodiment of the present invention. Moreover, 23a represents the base material of the optical film which concerns on one form of this invention, and 23b represents the reflection layer of the optical film which concerns on one form of this invention, respectively.

Hereinafter, embodiments of the present invention will be described. In addition, this invention is not limited only to the following embodiment. In addition, the dimensional ratios in the drawings are exaggerated for convenience of explanation, and may be different from the actual ratios.

In this specification, “X to Y” indicating a range means “X or more and Y or less”. Unless otherwise specified, operations and physical properties are measured under conditions of room temperature (20 to 25 ° C.) / Relative humidity 40 to 50% RH.

Further, in the present specification, the notation “(meth) acryl” in the specific name of the compound means “acryl” and “methacryl”, “(meth) acryloyl” means “acryloyl” and “methacryloyl”, “(meth) acrylate” "Represents" acrylate "and" methacrylate ", respectively. The “acrylic resin” refers to a resin having an acrylic acid ester, a methacrylic acid ester or a derivative thereof as a constituent component of the (co) polymer. The “acrylic resin” includes resins having other monomers as a constituent component of the copolymer in addition to the above monomers.

<Optical film>
In one embodiment of the present invention, an optical film has a base material and a reflective layer, and the base material and the reflective layer have a storage elastic modulus (E ′) at 150 ° C. (Measurement condition: JIS K7244-1: 1998) The absolute value of the difference in compliance, tension mode, temperature increase rate 5 ° C./min, frequency 10 Hz) is 0.05 GPa or more, and loss factor (tan δ) at 150 ° C. (Measurement conditions: JIS K7244-1: 1998 compliant, tension The mode, the temperature increase rate is 5 ° C./min, and the frequency is 10 Hz) is 0.12 to 0.20. According to the optical film according to the present embodiment, even when the high-temperature physical properties of the optical film substrate and the reflective layer are greatly different, generation of wrinkles in the optical film processing step can be sufficiently suppressed.

Here, first, the present inventors presume a mechanism capable of solving the above-described problems by the optical film according to one embodiment of the present invention as follows.

When the high-temperature physical properties of the base material and the reflective layer are greatly different from each other, the deformation behavior is different, and stress is generated between the base material and the reflective layer, causing wrinkles. Thus, the wrinkles are not sufficiently improved only by increasing the deformation of the optical film in the processing step by increasing the thermal shrinkage rate of the optical film as in the prior art and by reducing the remaining portion of the film. Moreover, even if it controls so that the thermal contraction rate of a base material and a reflective layer may become the same value at this time, since a load is added with a heat | fever in a process, the storage elastic modulus (E ') etc. in the high temperature of each layer etc. Since they are different, the difference in deformation behavior is not eliminated, and the above problem is not solved.

Note here the ease of plastic deformation of the entire optical film. As an index representing the ease of plastic deformation, loss factor (tan δ) can be mentioned. The loss coefficient (tan δ) is a value defined as tan δ = E ″ / E ′ (E ′: storage elastic modulus, E ″: loss elastic modulus). The storage elastic modulus (E ′) and loss elastic modulus (E ″) are the strain in the same phase as the strain in the complex elastic modulus generated when a sinusoidal distortion (deformation) is applied to the sample by vibration. This represents the real number component in which energy is stored as stress, and the imaginary number component in which the phase is advanced by 90 ° from the strain and the strain energy is converted into other energy to generate a loss. By setting the coefficient (tan δ) to a predetermined value or more, plastic deformation of the entire optical film can be more easily generated, and stress generated between the base material and the reflective layer is relieved. In addition, since the plastic deformation of the entire film is facilitated, the effect of reducing the excess portion of the optical film can be obtained. Even in the case of large differences, the wrinkles of the optical film can be sufficiently suppressed, and the loss factor (tan δ) at a high temperature is not more than a predetermined value, so that the amount of deformation of the film becomes excessive and the reflective layer Thus, the optical film can have high reflection performance.

Note that the above mechanism is based on speculation, and its correctness does not affect the technical scope of the present invention.

The optical film according to one embodiment of the present invention has a base material and a reflective layer as essential. In addition, a functional layer other than those described above or a further base material may be disposed at any position on each outer layer, between the layer and the base material, or on the outermost layer and the base material.

Here, in the optical film according to one embodiment of the present invention, the absolute value of the difference in storage elastic modulus (E ′) at 150 ° C. between the base material and the reflective layer is 0.05 GPa or more. In a conventional optical film, an optical film having an absolute value of a difference in storage elastic modulus (E ′) at 150 ° C. between the base material and the reflective layer of 0.05 GPa or more is due to a difference in high temperature physical properties between the base material and the reflective layer. In addition, it is difficult to sufficiently suppress wrinkles with a known wrinkle suppressing means for controlling the heat shrinkage rate. On the other hand, the optical film according to one embodiment of the present invention can sufficiently suppress the generation of wrinkles in the processing step of the optical film even when the high-temperature physical properties of the substrate and the reflective layer are greatly different. Here, it is preferable that the absolute value of the difference in storage elastic modulus (E ′) at 150 ° C. is larger from the viewpoint that a thin film can be formed when it is necessary to use a high elastic modulus material. The difference in absolute value of the storage elastic modulus (E ′) at 150 ° C. is preferably 13.20 GPa or less from the viewpoint of interfacial peeling between the substrate and the reflective layer. From the same viewpoint, it is more preferably 1.50 to 13.20 GPa, further preferably 1.50 to 13.00 GPa, and further preferably 2.00 to 7.00 GPa.

The storage elastic modulus (E ′) at 150 ° C. is increased in a tensile mode using a dynamic viscoelasticity automatic measuring instrument (DDV-01GP manufactured by A & D Corporation) in accordance with JIS K7244-1: 1998. It can be measured at a temperature rate of 5 ° C./min and a frequency of 10 Hz. The measurement is performed in any one direction in the plane and the direction orthogonal thereto, and the average value is taken as the evaluation result. Here, the measurement direction is not particularly limited, but for example, a machine direction and a direction perpendicular to the machine direction are preferable. In the present specification, the “machine direction” means the same direction as the film forming direction of the substrate, the reflective layer or the optical film. In this case, the machine direction coincides with the longitudinal direction of the film. Detailed measurement methods are described in the examples.

The optical film according to one embodiment of the present invention has a loss coefficient (tan δ) value at 150 ° C. of 0.12 to 0.20. As described in the above estimation mechanism, when the loss coefficient (tan δ) at 150 ° C. of the optical film is less than 0.12, the generation of wrinkles cannot be sufficiently suppressed. Further, if the loss coefficient (tan δ) at 150 ° C. is more than 0.20, sufficient optical characteristics cannot be obtained. From such a viewpoint, the value of the loss coefficient (tan δ) at 150 ° C. is more preferably 0.12 to 0.19, further preferably 0.13 to 0.18, and more preferably 0.15 to 0.18. Particularly preferred is 0.18.

The loss factor (tan δ) at 150 ° C. can be obtained as follows. First, the storage elastic modulus (E ′) and loss elastic modulus (E ″) were measured using a dynamic viscoelasticity automatic measuring device (DDV-01GP manufactured by A & D Corporation) in accordance with JIS K7244-1: 1998. Then, in the tensile mode, measurement is performed with a temperature increase rate of 5 ° C./min and a frequency of 10 Hz, and then, from the obtained result, E ″ / E ′ is calculated to obtain a loss coefficient (tan δ). The measurement is performed in any one direction in the plane and the direction orthogonal thereto, and the average value is taken as the evaluation result. Here, the measurement direction is not particularly limited, but it is preferable to use, for example, a machine direction and a direction perpendicular to the machine direction and use an average value.

Here, the method for controlling the loss factor (tan δ) of the optical film at 150 ° C. is not particularly limited, and examples thereof include selection of the material and manufacturing method of the base material and the reflective layer. Further, the loss coefficient (tan δ) at 150 ° C. of the optical film can be increased by reducing the storage elastic modulus (E ′) at 150 ° C. of the substrate or the reflective layer, increasing the thermal shrinkage rate, or the like. it can. Moreover, when a base material is a general resin film which is illustrated in the description of the base material described later, the ratio of the base material film thickness to the total film thickness of the base material and the reflective layer is increased. Alternatively, it can be increased by reducing the ratio of the film thickness of the reflective layer.

The thickness of the optical film is not particularly limited, but is preferably 20 to 300 μm, more preferably 25 to 100 μm, and further preferably 30 to 60 μm from the viewpoints of prevention of bending, visible light transmittance, handleability, and the like. preferable.

Hereinafter, each component of the optical film will be described in detail.

[Base material]
The base material used for the optical film according to one embodiment of the present invention serves as a support for the optical film.

The base material according to one embodiment of the present invention is such that the absolute value of the difference in storage elastic modulus (E ′) at 150 ° C. between the base material and the reflective layer is 0.05 GPa or more, and 150 ° C. of the optical film. The manufacturing method, material, thickness, and the like are set so that the loss coefficient (tan δ) at 0.1 is 0.12 to 0.20.

Here, the value of the storage elastic modulus (E ′) of the substrate at 150 ° C. is not particularly limited, but is 0.001 GPa or more and a value smaller than the storage elastic modulus of the reflective layer at 150 ° C. Is preferred. The plastic deformation during the heat processing of the optical film tends to occur more easily when the value of the storage elastic modulus (E ′) at 150 ° C. of the base material or the reflective layer is smaller. Here, it is easier to select a base material having a low storage elastic modulus than to require a lower storage elastic modulus for a reflective layer that requires high reflection performance, thereby causing plastic deformation more easily. be able to. This is presumed that by selecting a substrate having a small storage elastic modulus (E ′), plastic deformation can be caused more easily and wrinkles can be more easily suppressed. ing. Further, the storage elastic modulus (E ′) at 150 ° C. of the substrate is preferably 0.001 GPa or more because the reflection performance after heat processing can be further improved. This is presumed to be because, when the optical film has such a base material, fluctuations in the thickness of the reflective layer caused by excessive deformation of the base material can be further suppressed. From the same viewpoint, the value of the storage elastic modulus (E ′) at 150 ° C. of the substrate is preferably 0.01 GPa to 2.00 GPa, more preferably 0.10 to 1.00 GPa. It is more preferably 20 to 0.80 GPa, particularly preferably 0.30 to 0.50 GPa, and most preferably 0.35 to 0.45 GPa.

As a method for measuring the storage elastic modulus (E ′) at 150 ° C., it can be measured using the same method as the storage elastic modulus (E ′) at 150 ° C. of the optical film. Detailed measurement methods are described in the examples.

The value of the loss factor (tan δ) of the substrate at 150 ° C. is not particularly limited, but is preferably 0.12 to 0.45. By setting the loss coefficient (tan δ) at 150 ° C. of the substrate to 0.12 or more, the plastic deformability of the substrate can be further improved. This is because the plastic deformation of the base material is further improved, so that plastic deformation of the entire optical film can be more easily generated, and wrinkles of the optical film can be further suppressed. I guess. Moreover, the reflective performance after heat processing can be made more favorable by making the loss coefficient (tan-delta) in high temperature into 0.45 or less. This is presumed to be because the film thickness variation of the reflective layer is prevented from being caused by excessive deformation of the substrate, and the optical film can have higher reflection performance. From the same viewpoint, it is more preferably 0.12 to 0.40, further preferably 0.12 to 0.30, and particularly preferably 0.15 to 0.30.

As a method for measuring the loss factor (tan δ) at 150 ° C., it can be measured using the same method as the loss factor (tan δ) at 150 ° C. of the optical film. Detailed measurement methods are described in the examples.

Here, the method for controlling the loss factor (tan δ) of the optical film at 150 ° C. is not particularly limited, and examples thereof include selection of the material and the production method of the base material. As a manufacturing method, when a base material is a general resin film which is illustrated in description of the below-mentioned base material, heat processing conditions, extending conditions, etc. are mentioned, for example. The loss coefficient (tan δ) of the substrate at 150 ° C. can be increased by increasing the heat treatment temperature or shortening the heat treatment time, for example. Further, the loss coefficient (tan δ) of the substrate at 150 ° C. can be increased by decreasing the storage elastic modulus (E ′) of the substrate at 150 ° C., increasing the thermal shrinkage rate, or the like.

Further, the value of the heat shrinkage rate of the substrate at 30 ° C. for 30 minutes is not particularly limited, but is preferably 2.0 to 10.0%. When the value of the heat shrinkage ratio of the reflective layer at 150 ° C. for 30 minutes is 2.0% or more, the effect of suppressing wrinkles becomes higher. This is presumed that the base material having such a value can increase the deformation of the optical film, reduce the surplus portion of the film, and further improve the plastic deformability of the optical film. . Moreover, the reflective performance after heat processing can be made more favorable in the value of the thermal contraction rate in 150 degreeC 30-minute time-lapse | temporal of a reflection layer being 10.0% or less. This is presumed to be because the film thickness variation of the reflective layer is prevented from being caused by excessive deformation of the substrate, and the optical film can have higher reflection performance. From the same viewpoint, the value of the heat shrinkage rate of the reflective layer after 30 minutes at 150 ° C. is more preferably 2.0 to 8.0%, and more preferably 2.0 to 7.0%. 2.0 to 5.0% is more preferable, 2.5 to 5.0% is particularly preferable, and 3.0 to 5.0% is most preferable.

The following method can be used as a method for measuring the thermal shrinkage rate at 150 ° C. for 30 minutes. After storing the base material and the reflective layer in an environment of a temperature of 23 ° C. and a relative humidity of 55% RH for 24 hours, two marks are made at intervals of 100 mm in the width direction, and a distance L1 between the two marks in an unloaded state. Is measured using a microscope or the like. Subsequently, the sample is hung in an oven at 150 ° C. and left for 30 minutes. After 30 minutes, the sample is removed from the oven and stored again in an environment of a temperature of 23 ° C. and a relative humidity of 55% RH for 24 hours. Next, the distance L2 between the two marks of the unloaded sample is measured using a microscope or the like. Then, from the measured distances L1 and L2, the thermal contraction rate of the sample is calculated by the following formula;
Thermal contraction rate (%) = ((L1-L2) / L1) × 100
Here, the measurement direction is not particularly limited, but it is preferable to use, for example, a machine direction and a direction perpendicular to the machine direction and use an average value.

The thickness of the substrate according to one embodiment of the present invention is not particularly limited, but is preferably in the range of 10 to 300 μm, more preferably in the range of 20 to 100 μm, and more preferably 30 to 60 μm. More preferably. If the thickness is 10 μm or more, wrinkles during handling are less likely to occur, and if the thickness is 300 μm or less, the ability to follow a curved glass surface when bonded to glass is improved and wrinkles are less likely to occur. Become.

When the substrate is a general resin film as described later, the thickness of the substrate is from the viewpoint of increasing the loss factor (tan δ), with respect to the total thickness of the substrate and the reflective layer, It is preferable to occupy a ratio of 86.5% or more. Moreover, it is preferable to occupy a ratio of 97.5% or less from the viewpoint of reflection performance. From the same viewpoint, when the substrate is a resin film, the thickness of the substrate preferably occupies a ratio of 86.7 to 97.3%, and occupies a ratio of 86.9 to 97.2%. It is preferable.

The base material according to one embodiment of the present invention is preferably transparent. As an optical characteristic of the film for laminated glass, the visible light transmittance measured by JIS R 3106: 1998 is preferably 70% or more, more preferably 80% or more, and further preferably 90% or more.

(Resin film)
The substrate according to one embodiment of the present invention is preferably a resin film. The resin for forming the resin film is not particularly limited. For example, polyolefin (for example, polyethylene, polypropylene, etc.), polyester (for example, polyethylene terephthalate, polyethylene naphthalate, etc.), polyvinyl chloride, cellulose triacetate, polyimide, poly Butyral, cycloolefin polymer, cellulose nanofiber, etc. can be used. Among these, polyester is preferable.

The polyester is not particularly limited, but is preferably a polyester having a film-forming property having a dicarboxylic acid component and a diol component as main components. The main constituent dicarboxylic acid components include terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, diphenylsulfone dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenylethanedicarboxylic acid, Examples thereof include cyclohexane dicarboxylic acid, diphenyl dicarboxylic acid, diphenyl thioether dicarboxylic acid, diphenyl ketone dicarboxylic acid, and phenylindane dicarboxylic acid. As the dicarboxylic acid component, these acid anhydrides, acid halides or esters may be used. Examples of the diol component include ethylene glycol, propylene glycol, tetramethylene glycol, cyclohexanedimethanol, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxyethoxyphenyl) propane, bis ( 4-Hydroxyphenyl) sulfone, bisphenol fluorene hydroxyethyl ether, diethylene glycol, neopentyl glycol, hydroquinone, cyclohexanediol and the like. Among the polyesters comprising these as main components, terephthalic acid, 2,6-naphthalenedicarboxylic acid, or acid anhydrides or acids thereof are used as dicarboxylic acid components from the viewpoint of transparency, mechanical strength, dimensional stability, and the like. A polyester having a halide or ester as a diol component and ethylene glycol or 1,4-cyclohexanedimethanol as a main component is preferred. Among these, polyesters mainly composed of polyethylene terephthalate and polyethylene naphthalate, copolymerized polyesters composed of terephthalic acid, 2,6-naphthalenedicarboxylic acid and ethylene glycol, and mixtures of two or more of these polyesters are mainly used. Polyester as a constituent component is more preferable. Among these, polyethylene terephthalate is particularly preferable.

The resin film may contain particles under conditions that do not impair transparency in order to facilitate handling. Examples of particles used in the present invention include inorganic particles such as calcium carbonate, calcium phosphate, silica, kaolin, talc, titanium dioxide, alumina, barium sulfate, calcium fluoride, lithium fluoride, zeolite, molybdenum sulfide, and crosslinked polymers. Examples thereof include organic particles such as particles and calcium oxalate. Examples of the method of adding particles include a method of adding particles in the resin material as a raw material and a method of adding them directly to an extruder. One of these methods is adopted. Alternatively, two methods may be used in combination. In this invention, you may add an additive other than the said particle | grain as needed. Examples of such additives include stabilizers, lubricants, crosslinking agents, antiblocking agents, antioxidants, dyes, pigments, ultraviolet absorbers and the like.

The resin film can be produced by a conventionally known general method. For example, an unstretched resin film that is substantially amorphous and not oriented can be produced by melting a resin as a material with an extruder, extruding it with an annular die or a T-die, and quenching. Further, the unstretched resin film is uniaxially stretched, the tenter-type sequential biaxial stretch, the tenter-type simultaneous biaxial stretch, the tubular-type simultaneous biaxial stretch, and the like by a known method such as the resin film flow (MD) direction or the resin. A stretched resin film can be produced by stretching in a direction perpendicular to the film flow direction (TD). The draw ratio in this case can be appropriately selected according to the resin as the raw material for the resin film, but is preferably 2 to 10 times in the MD direction and TD direction, respectively.

The resin film is more preferably a stretched film from the viewpoint of improving strength and suppressing thermal expansion. As such a film, a biaxially oriented polyester film is particularly preferable, but an unstretched or at least one stretched polyester film can be used as long as the obtained film does not depart from the gist of the present invention. . In addition, from the above viewpoint, the stretched film can be preferably used particularly for an automotive windshield.

Further, the resin film may be subjected to relaxation treatment or offline heat treatment from the viewpoint of controlling the loss factor (tan δ) at 150 ° C. The relaxation treatment is preferably carried out in the process from the heat setting during the stretching film forming process of the polyester film to the winding process after exiting the tenter. In the relaxation treatment, the treatment temperature (heat treatment temperature) is preferably from 80 to 200 ° C., more preferably from 100 to 180 ° C., and even more preferably from 110 to 170. By setting the treatment temperature (heat treatment temperature) to 80 ° C. or higher, the loss coefficient (tan δ) of the substrate at 150 ° C. can be further increased. Moreover, the loss coefficient (tan-delta) at 150 degreeC of a base material can be made smaller by making processing temperature (heat processing temperature) 200 degrees C or less. The treatment time (heat treatment time) is preferably 1 to 60 seconds. By setting the treatment time (heat treatment time) to 1 second or longer, the loss coefficient (tan δ) of the substrate at 150 ° C. can be further reduced. Further, by setting the treatment time (heat treatment time) to 60 seconds or less, the loss coefficient (tan δ) of the substrate at 150 ° C. can be further increased. From the same viewpoint, the treatment time is more preferably 1 to 50 seconds, and further preferably 2 to 40 seconds. In addition, the relaxation rate is preferably in the range of 0.1 to 10% in both the longitudinal direction and the width direction, and more preferably, the relaxation rate is 2 to 6%.

The resin film may have an undercoat layer. In the present invention, the undercoat layer is a water-based easy-adhesive resin coating layer formed in a form directly adjacent to one side or both sides, and is a layer different from the reflective layer or the layer forming the reflective layer in the present application. To do. Here, the aqueous easy-adhesive resin coating layer is a layer obtained by applying an aqueous easy-adhesive coating liquid (undercoat layer coating liquid) containing a water-soluble resin having an easy-adhesion effect and water as a solvent. To express.
In the present invention, when the resin film has an undercoat layer directly adjacent to one or both sides thereof, a resin film having a subbing layer (a laminate comprising the undercoat layer and the resin film) is used as a base material. It shall be handled.

Here, it is preferable to apply the undercoat layer coating solution in-line on one or both surfaces of the resin film during the film formation process. In one embodiment of the present invention, the undercoating during the film forming process is referred to as in-line undercoating. Examples of the resin used in the useful undercoat layer coating liquid according to one embodiment of the present invention include polyester resins, acrylic-modified polyester resins, polyurethane resins, acrylic resins, vinyl resins, vinylidene chloride resins, polyethyleneimine vinylidene resins, and polyethyleneimine resins. , Polyvinyl alcohol resin, modified polyvinyl alcohol resin, gelatin and the like, and any of them can be preferably used. Among these, it is more preferable to use a water-soluble polyester resin or an acrylic-modified polyester resin. A conventionally well-known additive can also be added to these undercoat layers. The undercoat layer can be coated by a known method such as roll coating, gravure coating, knife coating, dip coating or spray coating. The coating amount of the undercoat layer is preferably about 0.01 to 5 g / m ² (dry state), more preferably about 0.01 to 2 g / m ² (dry state).

[Reflective layer]
The reflective layer according to one embodiment of the present invention is a layer having a function of reflecting part of incident light.

Note that the reflective layer according to one embodiment of the present invention is such that the absolute value of the difference in storage elastic modulus (E ′) at 150 ° C. between the base material and the reflective layer is 0.05 GPa or more, and The manufacturing method, material, thickness, etc. are set so that the loss coefficient (tan δ) at 150 ° C. is 0.12 to 0.20.

Here, the value of the storage elastic modulus (E ′) at 150 ° C. of the reflective layer is not particularly limited, but is preferably 2.00 to 13.50 GPa. When the value of the storage elastic modulus (E ′) at 150 ° C. of the reflective layer is 2.00 GPa or more, the reflective performance after heat processing can be further improved. This is presumed to be because by having such a reflective layer, it is possible to further suppress the film thickness variation of the reflective layer caused by excessive deformation of the reflective layer. In addition, when the value of the storage elastic modulus (E ′) at 150 ° C. of the reflective layer is 13.50 GPa or less, the effect of suppressing wrinkles becomes higher. This is presumed to be because the reflective layer having such a value can further improve the plastic deformability of the optical film. From the same viewpoint, the value of the storage elastic modulus (E ′) at 150 ° C. of the reflective layer is more preferably 2.20 to 13.20 GPa, further preferably 2.50 to 8.00 GPa, It is particularly preferably 2.60 to 7.00 GPa.

As a measuring method of the storage elastic modulus (E ′) at 150 ° C., the same method as the storage elastic modulus (E ′) of the optical film at 150 ° C. is used except that the measurement is performed using the sample for measuring the reflective layer. Can be measured. Detailed measurement methods are described in the examples.

Further, the value of the heat shrinkage rate of the reflective layer after 30 minutes at 150 ° C. is not particularly limited, but is preferably 0.5% to 5.0%. When the value of the heat shrinkage rate at 150 ° C. for 30 minutes of the reflective layer is 0.5% or more, the effect of suppressing wrinkles becomes higher. This is presumed that the reflection layer having such a value can increase the deformation of the optical film, reduce the excess portion of the film, and further improve the plastic deformability of the optical film. . Moreover, the reflective performance after heat processing can be made more favorable in the value of the thermal contraction rate in 150 degreeC 30-minute time-lapse | temporal of a reflection layer being 5.0% or less. This is presumed to be because by having such a reflective layer, it is possible to further suppress the film thickness variation of the reflective layer caused by excessive deformation of the reflective layer. From the same viewpoint, the value of the heat shrinkage ratio of the reflective layer after 30 minutes at 150 ° C. is more preferably 0.5 to 4.0%, and further preferably 1.0 to 3.0%. .

As a method for measuring the heat shrinkage rate at 150 ° C. for 30 minutes, the measurement is performed using the same method as the heat shrinkage rate at 150 ° C. for 30 minutes, except that measurement is performed using a sample for measuring a reflective layer. can do. Detailed measurement methods are described in the examples.

The thickness of the reflective layer is not particularly limited, but is preferably 1.2 μm to 7.8 μm. When the thickness of the reflective layer is 1.2 μm or more, the reflection performance can be further improved. Further, when the thickness of the reflective layer is 7.8 μm or less, the effect of suppressing wrinkles becomes higher. This is presumed to be because the reflective layer having such a value can further improve the plastic deformability of the optical film. From the same viewpoint, the thickness of the reflective layer is more preferably 1.2 to 7.6 μm or less, and further preferably 1.4 to 4.5 μm.

The method for measuring the thickness of the reflective layer is obtained by cutting a slice of the optical film and observing the cross section with an electron microscope (FE-SEM, S-5000H, manufactured by Hitachi, Ltd.). Can do. Detailed measurement methods are described in the examples.

Here, the reflective layer is preferably a reflective layer that selectively transmits light having a specific wavelength, and more preferably an infrared reflective film that transmits light having a wavelength in the visible region to the infrared region.

The reflective layer that selectively transmits light of a specific wavelength is not particularly limited. For example, a dielectric layer that alternately stacks refractive index layers having different refractive indexes and reflects only light having a wavelength according to the layer thickness. A multilayer film etc. can be mentioned.

(Dielectric multilayer film)
The reflective layer used in the optical film according to the present invention is preferably a dielectric multilayer film configured by alternately laminating low refractive index layers and high refractive index layers.

In this specification, the terms “high refractive index layer” and “low refractive index layer” refer to a refractive index layer having a higher refractive index when comparing the refractive index difference between two adjacent layers. It means that the lower refractive index layer is a low refractive index layer. Therefore, the terms “high refractive index layer” and “low refractive index layer” are the same when each refractive index layer constituting the light reflecting film is focused on two adjacent refractive index layers. All forms other than those having a refractive index are included.

Further, as an optical characteristic of an optical film having a dielectric multilayer film as a reflective layer, the transmittance in the visible light region measured according to JIS R 3106: 1998 is 60% or more, and the light is reflected in a wavelength region of 800 to 1400 nm. It is preferable to have a region where the rate exceeds 50%.

From the viewpoint of adhesion to other adjacent members such as a base material and other layers, haze and visible light transmittance, the reflective layer is at least the surface roughness of the refractive index layer in contact with the other adjacent members is the arithmetic average surface The roughness (Ra) is preferably 10 to 100 nm, more preferably 10 to 50 nm, and even more preferably 12 to 20 nm. When the arithmetic average surface roughness (Ra) of the refractive index layer is 10 nm or more, the adhesion between the reflective layer and the adjacent member can be increased due to the anchor effect. When the arithmetic average surface roughness is 100 nm or less, the haze and visible light transmittance can be prevented from decreasing without disturbing the interface between the reflective layer and the adjacent member. In addition, although it does not restrict | limit especially as an adjacent member, When the optical film which concerns on one form of this invention is used for a laminated glass use, the below-mentioned intermediate | middle layer etc. are mentioned, for example.

The thickness per layer of the high refractive index layer is preferably 20 to 800 nm, and more preferably 50 to 350 nm. Further, the thickness per layer of the low refractive index layer is preferably 20 to 800 nm, and more preferably 50 to 350 nm.

Here, when measuring the thickness per layer, the high refractive index layer and the low refractive index layer may have a clear interface between them or may change gradually. When the interface gradually changes, the maximum refractive index−minimum refractive index = Δn in the region where the refractive index continuously changes due to the mixing of the layers, the minimum refractive index between two layers + Δn The point of / 2 is regarded as the layer interface. The same applies to the layer thickness of the low refractive index layer described later.

The metal oxide concentration profile of the reflective layer formed by alternately laminating the high refractive index layer and the low refractive index layer is etched from the surface to the depth direction using a sputtering method, and an XPS surface analyzer is used. Then, the outermost surface can be set to 0 nm, sputtered at a rate of 0.5 nm / min, and the atomic composition ratio can be measured. It is also possible to view the cut surface by cutting the laminated film and measuring the atomic composition ratio with an XPS surface analyzer. In the mixed region, when the concentration of the metal oxide changes discontinuously, the boundary can be confirmed by a tomographic photograph using an electron microscope (TEM).

The XPS surface analyzer is not particularly limited and any model can be used. For example, ESCALAB-200R manufactured by VG Scientific, Inc. can be used. Mg can be used for the X-ray anode, and measurement can be performed at an output of 600 W (acceleration voltage: 15 kV, emission current: 40 mA).

In terms of productivity, the reflective layer preferably has a total number of high refractive index layers and low refractive index layers in the range of 6 to 100 layers, more preferably 7 to 60 layers, and still more preferably 8 layers. Is 55 layers, particularly preferably 8 to 40 layers, and most preferably 9 to 30 layers.

The reflective layer is preferably designed so that the difference in refractive index between the high refractive index layer and the low refractive index layer is large, so that the reflectance can be increased with a small number of layers. In one embodiment of the present invention, the difference in refractive index between the adjacent high refractive index layer and low refractive index layer is preferably 0.1 or more, more preferably 0.3 or more, and further preferably 0.35 or more. Yes, more preferably 0.4 or more. However, regarding the outermost layer and the lowermost layer, a configuration outside the above preferred range may be used.

Further, the reflectance in a specific wavelength region is determined by the difference in refractive index between two adjacent layers and the number of layers, and the larger the difference in refractive index, the same reflectance can be obtained with a smaller number of layers. The refractive index difference and the required number of layers can be calculated using commercially available optical design software. For example, in order to obtain a near-infrared reflectance of 90% or more, if the difference in refractive index is smaller than 0.1, it is necessary to laminate 200 layers or more, which not only decreases productivity but also at the lamination interface. Scattering increases, transparency decreases, and it becomes very difficult to manufacture without failure. From the standpoint of improving reflectivity and reducing the number of layers, there is no upper limit to the difference in refractive index, but practically about 1.4 is the limit.

The low refractive index layer and the high refractive index layer preferably contain a resin component. If the refractive index layer is formed of a resin component, a film forming method such as coating or spin coating can be selected. Since these methods are simple and do not ask the heat resistance of a base material, there are many choices, and it can be said that it is an effective film forming method particularly for a resin base material. For example, a mass production method such as a roll-to-roll method can be adopted for the coating type, which is advantageous in terms of cost and process time. Moreover, since the film | membrane containing a polymer material has high flexibility, even if it winds up at the time of production or conveyance, these defects do not generate easily and there exists an advantage that it is excellent in handleability. Moreover, it is also possible to form a reflective layer using the above polymer by a continuous flat film production line, for example, by a coextrusion method or a co-casting method.

The polymer material contained in the high refractive index layer and the low refractive index layer is preferably a water-soluble binder resin that functions as a binder.

Here, in the optical film according to one embodiment of the present invention, the first and second water-soluble binder resins contained in the high refractive index layer or the low refractive index layer are preferably polyvinyl alcohol. Moreover, it is preferable that the saponification degree of the polyvinyl alcohol contained in the high refractive index layer is different from the saponification degree of the polyvinyl alcohol contained in the low refractive index layer. The high refractive index layer preferably includes first metal oxide particles, and the low refractive index layer preferably includes second metal oxide particles. Here, the first metal oxide particles contained in the high refractive index layer are preferably titanium oxide particles surface-treated with a silicon-containing hydrated oxide.

It is preferable that at least one refractive index layer of the reflective layer includes a resin component having a glass transition temperature (Tg) of 40 ° C. to 70 ° C. A conventionally well-known thing can be used with a resin component, for example, water-soluble binder resin independent or the mixture of water-soluble binder resin and latex is mentioned. The ratio of the resin component having a specific Tg is preferably 20 to 70% by mass, more preferably 25 to 65% by mass, and further preferably 30 to 65% by mass with respect to the total mass of one refractive index layer. % By mass. The refractive index layer includes, on at least one surface on the transparent substrate, a high refractive index layer containing a first water-soluble binder resin and first metal oxide particles having different refractive indexes, and a second water-soluble layer. It is preferable that the layer is formed by laminating at least one low refractive index layer containing a conductive binder resin and second metal oxide particles.

The reflective layer preferably contains a resin component having a glass transition temperature (Tg) of 40 to 70 ° C. of the refractive index layer in contact with at least another adjacent member. The refractive index layer in contact with other adjacent members may be either a high refractive index layer or a low refractive index layer, but is preferably a low refractive index layer from the viewpoint of adhesion to other adjacent members. When the resin component is a water-soluble binder resin alone, the glass transition temperature (Tg) of the refractive index layer can be controlled by adjusting the composition and degree of polymerization of the water-soluble binder resin, and the resin component is a water-soluble binder resin. In the case of a mixture of latex and latex, it can be controlled by the content of latex with respect to the total resin component.

(High refractive index layer)
In a preferred embodiment of the present invention, the high refractive index layer can contain a first water-soluble binder resin and first metal oxide particles. If necessary, in order to control the glass transition temperature (Tg) of the resin component, latex may be included as the resin component contained in the high refractive index layer. The high refractive index layer may further include at least one selected from the group consisting of a curing agent, other binder resin, a surfactant, and other additives.

The refractive index of the high refractive index layer is preferably 1.80 to 2.50, more preferably 1.90 to 2.20.

Hereinafter, the first water-soluble binder resin, latex, other binder resin, first metal oxide particles, curing agent, surfactant, and other additives will be described.

(First water-soluble binder resin)
The first water-soluble binder resin according to an embodiment of the present invention is a G2 glass filter (maximum pore size) when dissolved in water at a concentration of 0.5% by mass at the temperature at which the water-soluble binder resin is most dissolved. 40 to 50 μm) means that the mass of the insoluble matter separated by filtration is within 50 mass% of the added water-soluble binder resin.

The weight average molecular weight of the first water-soluble binder resin is preferably 1,000 or more and 200,000 or less, and more preferably 3,000 or more and 40,000 or less.

Here, the weight average molecular weight can be measured by a known method, for example, static light scattering, gel permeation chromatography (GPC), time-of-flight mass spectrometry (TOF-MASS), etc. Can do. In the present specification, the weight average molecular weight is a value measured by a gel permeation chromatography method which is a generally known method.

The content of the first water-soluble binder resin in the high refractive index layer is preferably 5 to 50% by mass and preferably 10 to 40% by mass with respect to 100% by mass of the solid content of the high refractive index layer. Is more preferable.

The first water-soluble binder resin is not particularly limited, but is preferably polyvinyl alcohol. Moreover, it is preferable that the 2nd water-soluble binder resin which exists in the low-refractive-index layer mentioned later is also polyvinyl alcohol. Therefore, hereinafter, polyvinyl alcohol contained in the high refractive index layer and the low refractive index layer will be described together.

(Polyvinyl alcohol)
In one form of this invention, it is preferable that a high refractive index layer and a low refractive index layer contain 2 or more types of polyvinyl alcohol from which saponification degree differs, respectively. Here, in order to distinguish, polyvinyl alcohol as the first water-soluble binder resin is referred to as polyvinyl alcohol (A), and polyvinyl alcohol as the second water-soluble binder resin is referred to as polyvinyl alcohol (B). In addition, when each refractive index layer contains a plurality of polyvinyl alcohols having different saponification degrees and polymerization degrees, the polyvinyl alcohol having the highest content in each refractive index layer is changed to polyvinyl alcohol (A ), And polyvinyl alcohol (B) in the low refractive index layer.

As used herein, “degree of saponification” refers to the ratio of hydroxyl groups to the total number of acetyloxy groups (derived from the starting vinyl acetate) and hydroxyl groups in polyvinyl alcohol.

In addition, when referring to “polyvinyl alcohol having the highest content in the refractive index layer” herein, the degree of polymerization is calculated assuming that the polyvinyl alcohol having a saponification degree difference of 3 mol% or less is the same polyvinyl alcohol. . However, a low polymerization degree polyvinyl alcohol having a polymerization degree of 1000 or less is a different polyvinyl alcohol (even if there is a polyvinyl alcohol having a saponification degree difference of 3 mol% or less, it is not regarded as the same polyvinyl alcohol). Specifically, when polyvinyl alcohol having a saponification degree of 90 mol%, a saponification degree of 91 mol%, and a saponification degree of 93 mol% is contained in the same layer by 10 mass%, 40 mass%, and 50 mass%, respectively. These three polyvinyl alcohols are the same polyvinyl alcohol, and these three mixtures are polyvinyl alcohol (A) or (B). The “polyvinyl alcohol having a saponification degree difference of 3 mol% or less” means that it is within 3 mol% when attention is paid to any polyvinyl alcohol. For example, 90 mol%, 91 mol%, 92 mol%, 94 mol % Of polyvinyl alcohol, when paying attention to 91 mol% of polyvinyl alcohol, the difference in saponification degree of any polyvinyl alcohol is within 3 mol%, so that the same polyvinyl alcohol is obtained.

When polyvinyl alcohol having a saponification degree different by 3 mol% or more is contained in the same layer, it is regarded as a mixture of different polyvinyl alcohols, and the polymerization degree and the saponification degree are calculated for each. For example, PVA203: 5% by mass, PVA117: 25% by mass, PVA217: 10% by mass, PVA220: 10% by mass, PVA224: 10% by mass, PVA235: 20% by mass, PVA245: 20% by mass, most contained A large amount of PVA (polyvinyl alcohol) is a mixture of PVA 217 to 245 (the difference in the degree of saponification of PVA 217 to 245 is within 3 mol%, and is the same polyvinyl alcohol), and this mixture is polyvinyl alcohol (A) or ( B). Thus, in the mixture of PVA 217 to 245 (polyvinyl alcohol (A) or (B)), the degree of polymerization was (1700 × 0.1 + 2000 × 0.1 + 2400 × 0.1 + 3500 × 0.2 + 4500 × 0.7) / 0.7 = 3200, and the degree of saponification is 88 mol%.

The difference in the absolute value of the saponification degree between the polyvinyl alcohol (A) and the polyvinyl alcohol (B) is preferably 3 mol% or more, and more preferably 5 mol% or more. If it is such a range, since the interlayer mixing state of a high refractive index layer and a low refractive index layer will become a preferable level, it is preferable. Moreover, although the difference of the saponification degree of polyvinyl alcohol (A) and polyvinyl alcohol (B) is so preferable that it is separated, it is 20 mol% or less from the viewpoint of the solubility to water of polyvinyl alcohol. It is preferable.

In addition, the saponification degree of polyvinyl alcohol (A) and polyvinyl alcohol (B) is preferably 75 mol% or more from the viewpoint of solubility in water. Furthermore, between polyvinyl alcohol (A) and polyvinyl alcohol (B), one of them has a saponification degree of 90 mol% or more and the other is 90 mol% or less. Is preferable for achieving a preferable level. It is more preferable that one of the polyvinyl alcohol (A) and the polyvinyl alcohol (B) has a saponification degree of 95 mol% or more and the other is 90 mol% or less. In addition, although the upper limit of the saponification degree of polyvinyl alcohol is not specifically limited, Usually, it is less than 100 mol%, Preferably it is 99.9 mol% or less.

Also, the polymerization degree of two kinds of polyvinyl alcohols having different saponification degrees is preferably 1,000 or more. This is because when the polymerization degree of polyvinyl alcohol is 1,000 or more, the frequency of occurrence of cracks in the coating film becomes lower. The polymerization degree of two kinds of polyvinyl alcohols having different saponification degrees is preferably 5,000 or less. This is because the coating solution is more stable when the polymerization degree of polyvinyl alcohol is 5,000 or less. In the present specification, “the coating solution is stable” means that the coating solution is stable over time. From the same viewpoint, those having a polymerization degree of 1,500 to 5,000 are more preferable, and those having a polymerization degree of 2,000 to 5,000 are more preferable. When the degree of polymerization of at least one of polyvinyl alcohol (A) and polyvinyl alcohol (B) is 2,000 to 5,000, the frequency of occurrence of cracks in the coating film is remarkably reduced, and the reflectance at a specific wavelength is improved. Because it does. Here, it is particularly preferable that both of the polyvinyl alcohol (A) and the polyvinyl alcohol (B) are 2,000 to 5,000, since the above-described effect can be more remarkably exhibited.

“Degree of polymerization” as used herein refers to a viscosity average degree of polymerization, which is measured according to JIS K 6726: 1994, and is the limit measured in water at 30 ° C. after completely re-saponifying and purifying PVA. It is obtained from the viscosity [η] (dl / g) by the following formula.

The polyvinyl alcohol (B) contained in the low refractive index layer preferably has a saponification degree of 75 mol% or more and 90 mol% or less and a polymerization degree of 2,000 or more and 5,000 or less. When such polyvinyl alcohol is contained in the low refractive index layer, interfacial mixing is further suppressed, which is preferable. This is considered to be because there are few cracks of a coating film and set property improves.

The polyvinyl alcohol (A) and (B) used in one embodiment of the present invention may be a synthetic product or a commercially available product. Examples of commercially available products used as polyvinyl alcohol (A) and (B) include PVA-102, PVA-103, PVA-105, PVA-110, PVA-117, PVA-120, PVA-124, and PVA-203. , PVA-205, PVA-210, PVA-217, PVA-220, PVA-224, PVA-235 (manufactured by Kuraray Co., Ltd.), JC-25, JC-33, JF-03, JF-04, JF -05, JP-03, JP-04JP-05, JP-45 (above, manufactured by Nippon Vineyard PVA).

The first water-soluble binder resin according to an embodiment of the present invention is partially modified in addition to normal polyvinyl alcohol obtained by hydrolyzing polyvinyl acetate unless the effects of the present invention are impaired. Modified polyvinyl alcohol may be included. When such modified polyvinyl alcohol is contained, the adhesion, water resistance, and flexibility of the film may be improved. Examples of such modified polyvinyl alcohol include cation-modified polyvinyl alcohol, anion-modified polyvinyl alcohol, nonion-modified polyvinyl alcohol, and vinyl alcohol polymers.

Examples of the cation-modified polyvinyl alcohol include primary to tertiary amino groups and quaternary ammonium groups as described in JP-A No. 61-10383 in the main chain or side chain of the polyvinyl alcohol. It is obtained by saponifying a copolymer of an ethylenically unsaturated monomer having a cationic group and vinyl acetate.

Examples of the ethylenically unsaturated monomer having a cationic group include trimethyl- (2-acrylamido-2,2-dimethylethyl) ammonium chloride and trimethyl- (3-acrylamido-3,3-dimethylpropyl) ammonium chloride. N-vinylimidazole, N-vinyl-2-methylimidazole, N- (3-dimethylaminopropyl) methacrylamide, hydroxylethyltrimethylammonium chloride, trimethyl- (2-methacrylamidopropyl) ammonium chloride, N- (1, And 1-dimethyl-3-dimethylaminopropyl) acrylamide. The ratio of the cation-modified group-containing monomer in the cation-modified polyvinyl alcohol is preferably 0.1 to 10 mol%, more preferably 0.2 to 5 mol%, relative to vinyl acetate.

Anion-modified polyvinyl alcohol is described in, for example, polyvinyl alcohol having an anionic group as described in JP-A-1-206088, JP-A-61-237681 and JP-A-63-307979. Examples thereof include a copolymer of vinyl alcohol and a vinyl compound having a water-soluble group, and a modified polyvinyl alcohol having a water-soluble group as described in JP-A-7-285265.

Nonionic modified polyvinyl alcohols include, for example, polyvinyl alcohol derivatives obtained by adding a polyalkylene oxide group to a part of vinyl alcohol as described in JP-A-7-9758, and JP-A-8-25795. Block copolymer of vinyl compound having hydrophobic group and vinyl alcohol, silanol-modified polyvinyl alcohol having silanol group, reactive group modification having reactive group such as acetoacetyl group, carbonyl group and carboxy group Polyvinyl alcohol etc. are mentioned.

Further, examples of the vinyl alcohol polymer include EXEVAL (registered trademark, manufactured by Kuraray Co., Ltd.) and Nichigo G polymer (registered trademark, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.).

Two or more kinds of modified polyvinyl alcohol can be used in combination, such as the degree of polymerization and the type of modification.

The content of the modified polyvinyl alcohol is not particularly limited, but is preferably 1 to 30% by mass with respect to the total mass (solid content) of each refractive index. If it is such a range, the said effect will be exhibited more.

In one embodiment of the present invention, it is preferable that two types of polyvinyl alcohol having different saponification degrees are used between layers having different refractive indexes.

For example, when polyvinyl alcohol (A) having a low saponification degree is used for the high refractive index layer and polyvinyl alcohol (B) having a high saponification degree is used for the low refractive index layer, the polyvinyl alcohol ( A) is preferably contained in the range of 40% by mass to 100% by mass with respect to the total mass of all polyvinyl alcohols in the layer, more preferably 60% by mass to 95% by mass, and the low refractive index layer The polyvinyl alcohol (B) is preferably contained in the range of 40% by mass to 100% by mass with respect to the total mass of all the polyvinyl alcohols in the low refractive index layer, and 60% by mass to 95% by mass. Is more preferable.

When polyvinyl alcohol (A) having a high saponification degree is used for the high refractive index layer and polyvinyl alcohol (B) having a low saponification degree is used for the low refractive index layer, the polyvinyl alcohol ( A) is preferably contained in the range of 40% by mass to 100% by mass with respect to the total mass of all polyvinyl alcohols in the layer, more preferably 60% by mass to 95% by mass, and the low refractive index layer The polyvinyl alcohol (B) is preferably contained in the range of 40% by mass to 100% by mass with respect to the total mass of all polyvinyl alcohols in the low refractive index layer. When the content of the polyvinyl alcohol (B) in the low refractive index layer is 40% by mass or more, interlayer mixing is suppressed, and the effect that the disturbance of the interface becomes smaller appears remarkably. On the other hand, if the content of the polyvinyl alcohol (B) in the low refractive index layer is 100% by mass or less, the stability of the coating solution is further improved. From the same viewpoint, the content of the polyvinyl alcohol (B) in the low refractive index layer is more preferably 60% by mass or more and 95% by mass or less.

(latex)
In one embodiment of the present invention, the high refractive index layer may contain latex as a resin component in addition to the water-soluble binder resin. Latex is a resin that is stably dispersed in an aqueous medium. As latex in one form of this invention, emulsion resin is mentioned, for example. The glass transition temperature (Tg) of the resin component can be controlled by the content of the latex with respect to the total of the resin components, and the heat resistance of the produced laminated glass is improved by including the latex as the resin component.

The content of the latex is preferably 1% by mass or more and 50% by mass or less, more preferably 5% by mass or more and less than 50% by mass with respect to the total (100% by mass) of the water-soluble binder resin and latex. More preferably, it is 5% by mass to 20% by mass.

The emulsion resin is a resin in which fine resin particles having an average particle diameter of about 0.01 to 2.0 μm, for example, are dispersed in an emulsion state in an aqueous medium. It can be obtained, for example, by emulsion polymerization using a molecular dispersant. There is no fundamental difference in the polymer component of the resulting emulsion resin depending on the type of dispersant used. Examples of the dispersant used in the polymerization of the emulsion include polyoxyethylene nonylphenyl ether in addition to low molecular weight dispersants such as alkyl sulfonate, alkylbenzene sulfonate, diethylamine, ethylenediamine, and quaternary ammonium salts. , Polymer dispersing agents such as polyoxyethylene lauryl ether, hydroxyethyl cellulose, and polyvinylpyrrolidone. When emulsion polymerization is performed using a polymer dispersant having a hydroxyl group, the presence of hydroxyl groups is estimated on at least the surface of fine particles, and the emulsion resin polymerized using other dispersants has chemical and physical properties of the emulsion. Different.

The polymer dispersant containing a hydroxyl group is a polymer dispersant having a weight average molecular weight of 10,000 or more, and has a hydroxyl group substituted on the side chain or terminal. For example, an acrylic polymer such as sodium polyacrylate or polyacrylamide is used. Examples of such polymers include 2-ethylhexyl acrylate copolymer, polyethers such as polyethylene glycol and polypropylene glycol, and polyvinyl alcohol. Polyvinyl alcohol is particularly preferable.

Polyvinyl alcohol used as a polymer dispersant is an anion-modified polyvinyl alcohol having an anionic group such as a cation-modified polyvinyl alcohol or a carboxyl group in addition to ordinary polyvinyl alcohol obtained by hydrolysis of polyvinyl acetate. Further, modified polyvinyl alcohol such as silyl-modified polyvinyl alcohol having a silyl group may be contained. Polyvinyl alcohol has a higher effect of suppressing the occurrence of cracks when the ink absorption layer is formed when the average degree of polymerization is higher, but when the average degree of polymerization is within 5000, the viscosity of the emulsion resin is not high, and at the time of production Easy to handle. Accordingly, the average degree of polymerization is preferably 300 to 5000, more preferably 1500 to 5000, and particularly preferably 3000 to 4500. The saponification degree of polyvinyl alcohol is preferably 70 to 100 mol%, more preferably 80 to 99.5 mol%.

Examples of the resin that is emulsion-polymerized with the above polymer dispersant include homopolymers or copolymers of ethylene monomers such as acrylic acid esters, methacrylic acid esters, vinyl compounds, and styrene compounds, and diene compounds such as butadiene and isoprene. A polymer is mentioned. More specifically, examples of the resin that is emulsion-polymerized with the polymer dispersant include acrylic resins (acrylic resins), styrene-butadiene resins, ethylene-vinyl acetate resins, and the like.

The acrylic resin is not particularly limited, but an acrylic resin or methacrylic acid ester having a proportion of 50 mol% or more is preferable when the total amount of the constituent monomers is 100 mol%.

As the acrylic resin, commercially available ones may be used. For example, AE120A (manufactured by Etec Co., Ltd.), Viniblanc (registered trademark) 2585, 2680 (manufactured by Nissin Chemical Industry Co., Ltd.), EK108 (Siden Chemical Co., Ltd.) And VONCOAT (registered trademark) CE-6400 (manufactured by DIC Corporation).

(Other binder resins)
In one embodiment of the present invention, the high refractive index layer can use other water-soluble binder resins in addition to the first water-soluble binder resin component as long as the effects of the present invention are not impaired. Other water-soluble binder resins are not particularly limited, but water-soluble polymers are preferable in consideration of environmental problems and coating film flexibility.

In the high refractive index layer, the content of the other binder resin used together with the first water-soluble binder resin component is 5 to 50% by mass with respect to 100% by mass of the solid content of the high refractive index layer. You can also.

That is, in one embodiment of the present invention, a water-soluble polymer other than polyvinyl alcohol and modified polyvinyl alcohol may be used as the binder resin in addition to the polyvinyl alcohol and modified polyvinyl alcohol as long as the effect is not impaired. The water-soluble polymer is when it is filtered through a G2 glass filter (maximum pores 40-50 μm) when dissolved in water at a concentration of 0.5% by mass at the temperature at which the water-soluble polymer is most dissolved. The mass of the insoluble matter separated by filtration is within 50% by mass of the added water-soluble polymer. Among such water-soluble polymers, gelatin, celluloses, thickening polysaccharides, or polymers having reactive functional groups are particularly preferable. These water-soluble polymers may be used alone or in combination of two or more.

(Resin component suitable for reflective layer formed by co-extrusion method or co-casting method)
In addition, when the reflective layer is formed using a co-extrusion method or a co-casting method, the resin component contained in the high refractive index layer is not particularly limited. For example, polyethylene terephthalate (PET), polyethylene terephthalate Copolymer (coPET), poly (methyl methacrylate) (PMMA), copolymer of poly (methyl methacrylate) (coPMMA), cyclohexanedimethanol (PETG), copolymer of cyclohexanedimethanol (coPETG), polyethylene naphthalate (PEN) polyethylene These include naphthalate copolymer (coPEN), polyethylene naphthalate, polyethylene naphthalate copolymer, poly (methyl methacrylate), and poly (methyl methacrylate) copolymer. In addition, as a resin component contained in a low refractive index layer, the thing similar to the resin component contained in a high refractive index layer can be mentioned. For each high refractive index layer and low refractive index layer, one or a combination of two or more of these polymers can be used. Examples of suitable polymer combinations include those described in US Pat. No. 6,352,761.

(First metal oxide particles)
As the first metal oxide particles according to one embodiment of the present invention, metal oxide particles having a refractive index of 2.0 or more and 3.0 or less are preferable. More specifically, for example, titanium oxide, zirconium oxide, zinc oxide, synthetic amorphous silica, colloidal silica, alumina, colloidal alumina, lead titanate, red lead, yellow lead, zinc yellow, chromium oxide, second oxide Examples include iron, iron black, copper oxide, magnesium oxide, magnesium hydroxide, strontium titanate, yttrium oxide, niobium oxide, europium oxide, lanthanum oxide, zircon, and tin oxide. Also, composite oxide particles composed of a plurality of metals, core-shell particles whose metal structure changes into a core-shell shape, or the like may be used.

In order to form a transparent high refractive index layer having a higher refractive index, the high refractive index layer according to one embodiment of the present invention contains metal oxide fine particles having a high refractive index such as titanium and zirconium. It is more preferable that titanium oxide fine particles or zirconia oxide fine particles are contained. Among these, titanium oxide is more preferable from the viewpoint of the stability of the coating liquid for forming the high refractive index layer. Among titanium oxides, the rutile type (tetragonal type) has lower catalytic activity than the anatase type, so that the weather resistance of the high refractive index layer and the adjacent layer is higher, and the refractive index is higher. Is particularly preferred.

Further, the titanium oxide may be in the form of core-shell particles coated with a silicon-containing hydrated oxide. The core-shell particles have a structure in which the surface of the titanium oxide particles is coated with a shell made of a silicon-containing hydrated oxide on a titanium oxide serving as a core. In this case, the volume average particle size of the titanium oxide particles serving as the core portion is preferably more than 1 nm and less than 30 nm, more preferably 4 nm or more and less than 30 nm, and more preferably 4 nm or more and less than 15 nm. By including such core-shell particles, the intermixing of the high refractive index layer and the low refractive index layer can be further suppressed by the interaction between the silicon-containing hydrated oxide of the shell layer and the water-soluble resin. it can.

The first metal oxide particles described above may be used alone or in combination of two or more.

The content of the first metal oxide particles is 15 to 80% by mass with respect to 100% by mass of the solid content of the high refractive index layer, from the viewpoint of providing a refractive index difference from the low refractive index layer. preferable. Furthermore, it is more preferably 20 to 77% by mass, and further preferably 30 to 75% by mass.

The volume average particle diameter of the first metal oxide particles is preferably 30 nm or less, more preferably 1 to 30 nm. When the volume average particle diameter of the first metal oxide particles is 1 nm or more and 30 nm or less, a high refractive index layer with less haze and better visible light transmittance can be formed. From the same viewpoint, the volume average particle size of the first metal oxide particles is more preferably 5 to 15 nm.

The volume average particle diameter of the first metal oxide particles refers to a method of observing the particles themselves using a laser diffraction scattering method, a dynamic light scattering method, or an electron microscope, or a cross section or surface of the refractive index layer. The particle size of 1,000 arbitrary particles is measured by a method of observing the appearing particle image with an electron microscope, and particles having particle sizes of d1, d2,. n2... ni... nk particles of a group of particulate metal oxides, where the volume per particle is vi, the volume average particle diameter mv = {Σ (vi · di)} / The average particle diameter is weighted by the volume represented by {Σ (vi)}.

Furthermore, the first metal oxide particles are preferably monodispersed. The monodispersion here means that the monodispersity obtained by the following formula is 40% or less. This monodispersity is more preferably 30% or less, and particularly preferably 0.1 to 20%.

(Curing agent)
In one embodiment of the present invention, a curing agent can be used to cure the first water-soluble binder resin. The curing agent that can be used together with the first water-soluble binder resin is not particularly limited as long as it causes a curing reaction with the water-soluble binder resin. For example, when polyvinyl alcohol is used as the first water-soluble binder resin, boric acid or a salt thereof is preferable as the curing agent. In addition to boric acid or a salt thereof, known ones can be used. In general, a compound having a group capable of reacting with polyvinyl alcohol or a compound that promotes the reaction between different groups possessed by polyvinyl alcohol. Select and use. Specific examples of the curing agent include, for example, epoxy curing agents (diglycidyl ethyl ether, ethylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-diglycidyl cyclohexane, N, N-diglycidyl- 4-glycidyloxyaniline, sorbitol polyglycidyl ether, glycerol polyglycidyl ether, etc.), aldehyde curing agents (formaldehyde, glioxal, etc.), active halogen curing agents (2,4-dichloro-4-hydroxy-1,3,5) , -S-triazine, etc.), active vinyl compounds (1,3,5-trisacryloyl-hexahydro-s-triazine, bisvinylsulfonylmethyl ether, etc.), aluminum alum and the like.

Boric acid or a salt thereof refers to an oxygen acid having a boron atom as a central atom and a salt thereof, specifically, orthoboric acid, diboric acid, metaboric acid, tetraboric acid, pentaboric acid, and octaboron. Examples include acids and their salts.

Boric acid having a boron atom or a salt thereof as a curing agent may be used alone or as a mixture of two or more. Particularly preferred is a mixed aqueous solution of boric acid and borax.

When preparing an aqueous solution, boric acid and borax can each be added only at a content that forms a relatively dilute aqueous solution, but by mixing both, a concentrated aqueous solution can be obtained. The coating solution can be concentrated. Further, there is an advantage that the pH of the aqueous solution to be added can be controlled relatively freely.

In one embodiment of the present invention, it is more preferable to use boric acid or a salt thereof, or borax as the curing agent. When boric acid or a salt thereof, or borax is used, the metal oxide particles and the water-soluble binder resin polyvinyl alcohol OH group and hydrogen bond network are more easily formed, and as a result, a high refractive index layer and It is considered that interlayer mixing with the low refractive index layer is suppressed, and preferable near-infrared blocking characteristics are achieved. In particular, when a set coating process is used in which a multilayer coating of a high refractive index layer and a low refractive index layer is applied with a coater, and after the film surface temperature of the coating film is once cooled to about 15 ° C., the film surface is dried. Can express an effect more preferably.

The content of the curing agent in the high refractive index layer is preferably 1 to 10% by mass and more preferably 2 to 6% by mass with respect to 100% by mass of the solid content of the high refractive index layer.

In particular, when polyvinyl alcohol is used as the first water-soluble binder resin, the total amount of the curing agent used is preferably 1 to 600 mg per 1 g of polyvinyl alcohol, more preferably 100 to 600 mg per 1 g of polyvinyl alcohol.

(Surfactant)
In one embodiment of the present invention, at least one of the high refractive index layers may further contain a surfactant. As the surfactant, any of zwitterionic, cationic, anionic, and nonionic types can be used. More preferably, a betaine zwitterionic surfactant, a quaternary ammonium salt cationic surfactant, a dialkylsulfosuccinate anionic surfactant, an acetylene glycol nonionic surfactant, or a fluorine cationic interface Activators are preferred.

As the surfactant, for example, commercially available products such as Softazoline (registered trademark) LSB-R (manufactured by Kawaken Fine Chemical Co., Ltd.) can be used.

The addition amount of the surfactant is preferably 0.005 to 0.30% by mass, and 0.01 to 0.10% by mass when the total mass of the coating solution for the high refractive index layer is 100% by mass. % Is more preferable.

(Other additives)
Various additives applicable to the high refractive index layer according to an embodiment of the present invention are listed below. For example, ultraviolet absorbers described in JP-A-57-74193, JP-A-57-87988, and JP-A-62-261476; JP-A-57-74192, JP-A-57-87989 No. 5, JP-A-60-72785, JP-A 61-146591, JP-A-1-95091, JP-A-3-13376, and the like; Fluorescent whitening described in JP-A-59-42993, JP-A-59-52689, JP-A-62-280069, JP-A-61-228771, JP-A-4-219266, etc. Agents; pH adjusters such as sulfuric acid, phosphoric acid, acetic acid, citric acid, sodium hydroxide, potassium hydroxide, potassium carbonate; antifoaming agents; lubricants such as diethylene glycol; antiseptics; Antistatic agent; Matting agent; Thermal stabilizer; Antioxidant; Flame retardant; Crystal nucleating agent; Inorganic particle; Organic particle; Thickening agent; Lubricant; Infrared absorber; Dye; Etc.

Here, in the case of using a pH adjuster, when the total mass of the coating solution for the high refractive index layer is 100% by mass, it is preferably 0.5 to 5.0% by mass, and 1.0 to 4. More preferably, it is 0% by mass.

<Low refractive index layer>
In a preferred embodiment of the present invention, the low refractive index layer can contain a second water-soluble binder resin and second metal oxide particles as a resin component. If necessary, as a resin component contained in the low refractive index layer, latex can be contained in addition to the water-soluble binder resin, similarly to the high refractive index layer. Moreover, you may include at least 1 sort (s) selected from the group which consists of another binder resin, a hardening | curing agent, surfactant, and another additive.

The refractive index of the low refractive index layer is preferably 1.10 to 1.60, more preferably 1.30 to 1.50.

Hereinafter, the second water-soluble binder resin, the other binder resin, and the second metal oxide particles will be described. In addition, since the same thing as a high refractive index layer can be used as a 2nd water-soluble binder resin, latex, a hardening | curing agent, surfactant, and another additive, these details are in a high refractive index layer. See description.

(Second water-soluble binder resin)
In one embodiment of the present invention, the second water-soluble binder resin may be the same as the first water-soluble binder resin.

The content of the second water-soluble binder resin in the low refractive index layer is preferably 20 to 99.9% by mass, and 25 to 80% by mass with respect to 100% by mass of the solid content of the low refractive index layer. More preferably, it is more preferably 21.5 to 25.0% by mass, and particularly preferably 22.5 to 24.5% by mass.

(latex)
In one embodiment of the present invention, the low refractive index layer may contain latex as a resin component in addition to the water-soluble binder resin. Latex is a resin that is stably dispersed in an aqueous medium. As the preferable latex, the same latexes as those mentioned for the high refractive index layer can be used.

The content of the latex is preferably 1% by mass or more and 50% by mass or less, more preferably 5% by mass or more and less than 50% by mass with respect to the total (100% by mass) of the water-soluble binder resin and latex. More preferably, it is 22.0 mass% or more and 49 mass% or less, More preferably, it is 30.0 mass% or more and 49 mass% or less, Most preferably, it is 30 mass% or more and 45.0 mass% or less, Most preferably, it is 30.0 mass% or more and 40.0 mass% or less, Most preferably, it is 30.0 mass% or more and 35.0 mass% or less.

(Other binder resins)
In one embodiment of the present invention, as the other binder resin that can be included in the low refractive index layer, the same binder resin as that in the high refractive index layer can be used.

In the low refractive index layer, the content of the other binder resin used together with the second water-soluble binder resin component is 0.1 to 10% by mass with respect to 100% by mass of the solid content of the low refractive index layer. It can also be used.

(Second metal oxide particles)
As the second metal oxide particles according to one embodiment of the present invention, silica (silicon dioxide) is preferably used. Specific examples of silica include synthetic amorphous silica and colloidal silica. Among these, it is more preferable to use acidic colloidal silica sol (colloidal silica dispersion), and it is more preferable to use colloidal silica sol dispersed in an organic solvent. In order to further reduce the refractive index, hollow fine particles having pores inside the particles can be used as the second metal oxide particles, and hollow fine particles of silica (silicon dioxide) are particularly preferable.

The second metal oxide particles (preferably silicon dioxide) preferably have an average particle size of 3 to 100 nm. The average particle diameter of primary particles of silicon dioxide dispersed in a primary particle state (particle diameter in a dispersion state before coating) is more preferably 3 to 50 nm, and further preferably 3 to 40 nm. It is particularly preferably 3 to 20 nm, and most preferably 4 to 10 nm. Moreover, as an average particle diameter of secondary particle | grains, it is preferable from a viewpoint with few hazes and excellent visible light transmittance | permeability that it is 30 nm or less.

The average particle diameter of the second metal oxide fine particles was determined by observing the particles themselves or the particles appearing on the cross section or surface of the refractive index layer with an electron microscope, measuring the particle diameter of 1,000 arbitrary particles, It is obtained as a simple average value (number average). Here, the particle diameter of each particle is represented by a diameter assuming a circle equal to the projected area.

The colloidal silica used in one embodiment of the present invention is obtained by heating and aging a silica sol obtained by metathesis with an acid of sodium silicate or the like and passing through an ion exchange resin layer. For example, JP-A-57-14091. JP, 60-219083, JP 60-219084, JP 61-20792, JP 61-188183, JP 63-17807, JP JP-A-4-93284, JP-A-5-278324, JP-A-6-92011, JP-A-6-183134, JP-A-6-297830, JP-A-7-81214, JP-A-7- No. 101142, JP-A-7-179029, JP-A-7-137431, International Publication No. 94/26530, etc. Those listed.

Such colloidal silica may be a synthetic product or a commercially available product. Examples of commercially available products include Snowtex (registered trademark) OXS (manufactured by Nissan Chemical Industries, Ltd.). The surface of the colloidal silica may be cation-modified, or may be treated with Al, Ca, Mg, Ba or the like.

In one embodiment of the present invention, hollow particles can be used as the second metal oxide particles. When hollow particles are used, the average particle pore size is preferably 3 to 70 nm, more preferably 5 to 50 nm, and even more preferably 5 to 45 nm. The average particle pore diameter of the hollow particles is the average value of the inner diameters of the hollow particles. In one embodiment of the present invention, the refractive index of the low refractive index layer is sufficiently lowered if the average particle pore diameter of the hollow particles is in the above range. The average particle diameter is 50 or more at random, which can be observed as an ellipse in a circular, elliptical or substantially circular shape by electron microscope observation, and obtains the pore diameter of each particle. Is obtained. In the present specification, the average particle pore diameter is the minimum distance among the distances between the outer edges of the pore diameter that can be observed as a circle, an ellipse, or a substantially circle or ellipse, between two parallel lines. Means.

In one embodiment of the present invention, the second metal oxide particles may be surface-coated with a surface coating component. In particular, when using metal oxide particles that are not core-shell as the first metal oxide particles according to the present invention, the surface of the second metal oxide particles is coated with a surface coating component such as polyaluminum chloride. It becomes difficult to aggregate with the metal oxide particles.

The content of the second metal oxide particles in the low refractive index layer is preferably 0.1 to 70% by mass, and preferably 30 to 70% by mass with respect to 100% by mass of the solid content of the low refractive index layer. More preferably, it is more preferably 45 to 65% by mass, still more preferably 55 to 65% by mass, particularly preferably 58 to 64% by mass, and 60 to 63% by mass. Most preferred.

The above-mentioned second metal oxide particles may be used alone or in combination of two or more from the viewpoint of adjusting the refractive index.

(Curing agent)
In one embodiment of the present invention, a curing agent can be used to cure the second water-soluble binder resin. As a preferable curing agent, the same ones as mentioned for the high refractive index layer can be used.

The content of the curing agent in the low refractive index layer is preferably 1.0 to 10.0% by mass, and 1.62 to 1.88% by mass with respect to 100% by mass of the solid content of the low refractive index layer. It is preferably 1.70 to 1.85% by mass.

In particular, when polyvinyl alcohol is used as the second water-soluble binder resin, the total amount of the curing agent used is preferably 1 to 600 mg per 1 g of polyvinyl alcohol, more preferably 100 to 600 mg per 1 g of polyvinyl alcohol.

(Surfactant)
In one embodiment of the present invention, at least one of the low refractive index layers may further contain a surfactant. As a preferable surfactant, the same surfactants as those mentioned for the high refractive index layer can be used.

The addition amount of the surfactant is preferably 0.01 to 2.00% by mass, preferably 0.01 to 1.00% by mass, when the total mass of the coating solution for the low refractive index layer is 100% by mass. % Is more preferable, and 0.01 to 0.10% by mass is even more preferable.

(Other additives)
In one embodiment of the present invention, other additives may be the same as those mentioned for the high refractive index layer.

(Manufacturing method of reflective layer)
The method for forming the reflective layer according to one embodiment of the present invention is not particularly limited. Preferably, a coating solution for a high refractive index layer containing a first water-soluble binder resin and first metal oxide particles on a substrate, a second water-soluble binder resin, and a second metal oxide The manufacturing method including the process of apply | coating the coating liquid for low refractive index layers containing object particle | grains can be implemented.

The coating method is not particularly limited, and for example, roll coating method, rod bar coating method, air knife coating method, spray coating method, slide curtain coating method, or U.S. Pat. No. 2,761,419, U.S. Pat. Examples thereof include a slide hopper coating method and an extrusion coating method described in Japanese Patent No. 2,761,791. In addition, as a method of applying a plurality of layers in a multilayer manner, sequential multilayer coating or simultaneous multilayer coating may be used, but simultaneous multilayer coating is preferable.

Hereinafter, the simultaneous multilayer coating by the slide hopper coating method, which is a preferable manufacturing method (coating method) of the present invention, will be described in detail.

(solvent)
The solvent for preparing the coating solution for the high refractive index layer and the coating solution for the low refractive index layer is not particularly limited, but water, an organic solvent, or a mixed solvent thereof is preferable.

The organic solvent is not particularly limited, and an appropriate solvent can be used. Specifically, for example, alcohols such as methanol, ethanol, 2-propanol and 1-butanol, esters such as ethyl acetate, butyl acetate, propylene glycol monomethyl ether acetate and propylene glycol monoethyl ether acetate, diethyl ether and propylene Examples include ethers such as glycol monomethyl ether and ethylene glycol monoethyl ether, amides such as dimethylformamide and N-methylpyrrolidone, and ketones such as acetone, methyl ethyl ketone, acetylacetone and cyclohexanone. These organic solvents may be used alone or in combination of two or more.

From the viewpoint of environment and ease of operation, water is particularly preferable as the solvent for the coating solution.

(Concentration of coating solution)
The concentration of the first water-soluble binder resin in the coating solution for the high refractive index layer is preferably 1 to 10% by mass. The concentration of the first metal oxide particles in the coating solution for the high refractive index layer is preferably 1 to 50% by mass.

The concentration of the second water-soluble binder resin in the coating solution for the low refractive index layer is preferably 1 to 10% by mass. The concentration of the second metal oxide particles in the coating solution for the low refractive index layer is preferably 1 to 50% by mass.

(Method for preparing coating solution)
The method for preparing the coating solution for the high refractive index layer and the coating solution for the low refractive index layer is not particularly limited. For example, a water-soluble binder resin, metal oxide particles, and other additives added as necessary. The method of adding and stirring and mixing is mentioned. At this time, the order of addition of the water-soluble binder resin, metal oxide particles, and other additives used as necessary is not particularly limited, and each component may be added and mixed sequentially while stirring, or stirring. However, they may be added and mixed at once. If necessary, it is further adjusted to an appropriate viscosity using a solvent.

The high refractive index layer may be formed using an aqueous coating solution for a high refractive index layer prepared by adding and dispersing core-shell particles. At this time, the core-shell particles are preferably prepared by adding to the coating solution for the high refractive index layer as a sol having a pH of 5.0 or more and 7.5 or less and a negative zeta potential of the particles.

(Viscosity of coating solution)
The viscosity at 30 to 45 ° C. of the coating solution for the high refractive index layer and the coating solution for the low refractive index layer when performing simultaneous multilayer coating by the slide hopper coating method is preferably in the range of 5 to 500 mPa · s, and 10 to 450 mPa · s. The range of s is more preferable. The viscosity at 30 to 45 ° C. of the coating solution for high refractive index layer and the coating solution for low refractive index layer when simultaneous multilayer coating is performed by the slide curtain coating method is preferably in the range of 5 to 1200 mPa · s, 25 A range of ˜500 mPa · s is more preferable.

The viscosity at 15 ° C. of the coating solution for the high refractive index layer and the coating solution for the low refractive index layer is preferably 100 mPa · s or more, more preferably 100 to 30,000 mPa · s, and more preferably 3,000 to 30,000 mPa · s. s is more preferable, and 10,000 to 30,000 mPa · s is particularly preferable.

(Coating and drying method)
The slide hopper coating method is a method of performing coating using a slide hopper coating apparatus.

The coating and drying method is not particularly limited, but the high refractive index layer coating solution and the low refractive index layer coating solution are heated to 30 ° C. or higher, and the high refractive index layer coating solution and the low refractive index are coated on the substrate. After the simultaneous application of the rate layer coating solution, the temperature of the formed coating film is preferably cooled (set) preferably to 1 to 15 ° C. and then dried at 10 ° C. or higher. More preferable drying conditions are a wet bulb temperature of 5 to 50 ° C. and a film surface temperature of 10 to 50 ° C. Moreover, as a cooling method immediately after application | coating, it is preferable to carry out by a horizontal set system from a viewpoint of the uniformity improvement of the formed coating film.

What is necessary is just to apply | coat so that the coating thickness of the coating liquid for high refractive index layers and the coating liquid for low refractive index layers may become the preferable thickness at the time of drying as shown above.

Here, the set means a step of increasing the viscosity of the coating composition and reducing the fluidity of the substances in each layer and in each layer by means such as applying cold air to the coating film to lower the temperature. To do. A state in which the cold air is applied to the coating film from the surface and the finger is pressed against the surface of the coating film is defined as a set completion state.

After application, the time (setting time) from application of cold air to completion of setting is preferably within 7 minutes, and preferably within 5 minutes. Further, the lower limit time is not particularly limited, but it is preferable to take 45 seconds or more. If the set time is 45 seconds or more, the components in the layer are more thoroughly mixed. On the other hand, if the set time is within 7 minutes, the difference in refractive index between the high refractive index layer and the low refractive index layer can be further prevented. If the intermediate layer between the high-refractive index layer and the low-refractive index layer is highly elastic, the setting step may not be provided.

The set time is such that the concentration of the water-soluble binder resin, the concentration of the metal oxide particles, etc., the addition of other components such as various known gelling agents such as gelatin, pectin, agar, carrageenan, gellan gum, etc. Can be adjusted.

The temperature of the cold air is preferably 0 to 25 ° C, more preferably 5 to 10 ° C. Further, the time during which the coating film is exposed to the cold air is preferably 10 to 120 seconds, although it depends on the transport speed of the coating film.

[Other layers]
In the optical film according to one embodiment of the present invention, a light absorbing layer, a heat insulating layer, an antistatic layer, a gas barrier layer, an antifouling layer, a deodorizing layer, a droplet layer are provided on the substrate for the purpose of adding further functions. Further, it may have functional layers such as an easy-sliding layer, a hard coat layer, an abrasion-resistant layer, and an antireflection layer.

Hereinafter, the light absorption layer, which is one of the other layers, will be described in detail.

(Light absorption layer)
The optical film according to one embodiment of the present invention may further have a light absorption layer on the substrate. Although it does not restrict | limit especially as a light absorption layer, For example, an infrared rays absorption layer etc. are mentioned. Further, the light absorption layer may be a layer that absorbs a specific wavelength by a dye or a pigment. Hereinafter, an infrared absorption layer will be described as an example, but a light absorption layer that can be used in the present invention is not limited to this.

Examples of materials contained in the infrared absorbing layer include polymers such as ultraviolet curable resins, photopolymerization initiators, and infrared absorbers. It is preferable that the polymer component contained in the infrared absorbing layer is cured. Here, the curing means that the reaction proceeds and cures by active energy rays such as ultraviolet rays or heat.

UV curable resins are superior in hardness and smoothness to other resins, and are also advantageous from the viewpoint of dispersibility of ITO (tin-doped indium oxide), ATO (antimony-doped tin oxide) and heat conductive metal oxides. is there. The ultraviolet curable resin can be used without particular limitation as long as it forms a transparent layer by curing, and examples thereof include silicone resins, epoxy resins, vinyl ester resins, acrylic resins, and allyl ester resins. Among these, acrylic resins are preferable from the viewpoints of hardness, smoothness, and transparency.

Acrylic resin is a reactive silica particle in which a photosensitive group having photopolymerization reactivity is introduced on its surface as described in International Publication No. 2008/035669 from the viewpoint of hardness, smoothness, and transparency ( In the following, it is preferable to simply include “reactive silica particles”. Here, examples of the photopolymerizable photosensitive group include a polymerizable unsaturated group represented by a (meth) acryloyloxy group. Further, the ultraviolet curable resin contains a photopolymerizable photosensitive group introduced on the surface of the reactive silica particles and a compound capable of photopolymerization, for example, an organic compound having a polymerizable unsaturated group. There may be.

In addition, a polymerizable unsaturated group-modified hydrolyzable silane reacts with a silica particle that forms a silyloxy group and is chemically bonded to the silica particle by a hydrolysis reaction of the hydrolyzable silyl group. Can be used as conductive silica particles. Here, the average particle diameter of the reactive silica particles is preferably 0.001 to 0.1 μm. By setting the average particle diameter in such a range, transparency, smoothness, and hardness can be satisfied in a well-balanced manner.

The acrylic resin preferably contains fluorine from the viewpoint of adjusting the refractive index. That is, the infrared absorption layer preferably contains fluorine. Examples of such an acrylic resin include an acrylic resin containing a structural unit derived from a fluorine-containing vinyl monomer. Examples of the fluorine-containing vinyl monomer include fluoroolefins (for example, fluoroethylene, vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, etc.), partial (meth) acrylic acid or fully fluorinated alkyl ester derivatives (for example, Osaka Organic Chemical Industry) Biscoat 6FM manufactured by Daikin Industries, Ltd., R-2020 manufactured by Daikin Industries, Ltd.), and fully or partially fluorinated vinyl ethers.

As the photopolymerization initiator, known ones can be used, either alone or in combination of two or more.

Inorganic infrared absorbers that can be contained in the infrared absorbing layer include ITO, ATO, zinc antimonate, lanthanum hexaboride (LaB ₆ ) from the viewpoints of visible light transmittance, infrared absorptivity, dispersibility in the resin, and the like. Cesium-containing tungsten oxide (for example, Cs _0.33 WO ₃ etc.) is preferable.

These can be used alone or in combination of two or more. The average particle size of the inorganic infrared absorber is preferably 5 to 100 nm, more preferably 10 to 50 nm. When it is 5 nm or more, dispersibility in the resin and infrared absorptivity become better. On the other hand, when it is 100 nm or less, the visible light transmittance is further improved.

The average particle size is measured by taking an image with a transmission electron microscope, extracting, for example, 50 particles at random, measuring the particle size, and averaging the results. Moreover, when the shape of particle | grains is not spherical, it defines as what was calculated by measuring a major axis.

The content of the inorganic infrared absorber in the infrared absorbing layer is preferably 1 to 80% by mass with respect to the total mass of the infrared absorbing layer. If the content of the inorganic infrared absorber is 1% or more, a higher infrared absorption effect appears, and if it is 80% or less, visible light can be transmitted more. From the same viewpoint, the content of the inorganic infrared absorber is more preferably 5 to 50% by mass.

Organic infrared absorbing materials include polymethine, phthalocyanine, naphthalocyanine, metal complex, aminium, imonium, diimonium, anthraquinone, dithiol metal complex, naphthoquinone, indolephenol, azo And triallylmethane compounds. Among these, metal complex compounds, aminium compounds (aminium derivatives), phthalocyanine compounds (phthalocyanine derivatives), naphthalocyanine compounds (naphthalocyanine derivatives), diimonium compounds (diimonium derivatives), squalium compounds (squarium derivatives) Etc. are particularly preferably used.

The infrared absorption layer may contain other infrared absorbers such as metal oxides other than those described above, organic infrared absorbers, metal complexes, and the like within the scope of the effects of the present invention. Specific examples of such other infrared absorbers include, for example, diimonium compounds, aluminum compounds, phthalocyanine compounds, organometallic complexes, cyanine compounds, azo compounds, polymethine compounds, quinone compounds, diphenylmethane compounds. And triphenylmethane compounds.

The thickness of the infrared absorbing layer is preferably in the range of 0.1 to 50 μm. If the thickness of the infrared absorbing layer is 0.1 μm or more, the infrared absorbing ability tends to be improved, while if it is 50 μm or less, the crack resistance of the coating film is further improved. From the same viewpoint, the thickness of the infrared absorption layer is more preferably in the range of 1 to 20 μm.

The method for forming the infrared absorbing layer is not particularly limited. For example, a method of forming the infrared absorbing layer coating liquid containing the above components, applying the coating liquid using a wire bar or the like, and drying the coating liquid. Etc.

The light absorption layer can also serve as a hard coat layer when the pencil hardness according to JIS K 5600-5-4: 1999 is H or higher. The form having a light absorption layer that also serves as a hard coat layer is used in an optical laminate in which an optical film and a single substrate are bonded, and the light absorption layer is preferably disposed in the outermost layer of the optical laminate.

The optical film according to a particularly preferred embodiment of the present invention is an optical film for bonding to a substrate having a curved surface. In addition, about the base | substrate which has a curved surface, it describes in detail in description of the optical laminated body mentioned later.

<Optical laminate>
Next, the substrate used for the optical layered body according to another embodiment of the present invention will be described. Here, the optical laminate includes an optical film according to one embodiment of the present invention and a substrate.

Hereinafter, the configuration of the entire optical film of the present embodiment will be described with reference to the drawings. In addition, the dimension ratio of drawing is exaggerated on account of description, and may differ from an actual ratio.

FIG. 1 is a schematic cross-sectional view showing an example of a laminated glass that is an optical laminate including the optical film of the present invention. Here, the optical laminated body 10 is a laminated glass, and a base body 11 having a curved surface on the outdoor side, an intermediate layer 12, an optical film 13, an intermediate layer 14, and a base body 15 having a curved surface on the indoor side are laminated in this order. It becomes. Here, the optical film 13 is arranged so that the base material 13a is on the base 15 side having a curved surface on the indoor side, and the reflective layer 13b is on the base 11 side having a curved surface on the outdoor side. However, the optical film according to the present invention is not limited to this structure.

FIG. 2 is a schematic sectional view showing another example of an optical laminate including the optical film of the present invention. Here, the optical layered body 20 is formed by arranging a base 21 having a curved surface, an intermediate layer 22 and an optical film 23 in this order. Here, the optical film 23 is disposed such that the base material 23a is on the side of the base 21 having a curved surface, and the reflection layer 23b is on the side opposite to the side of the base 21 having a curved surface. However, the optical film according to the present invention is not limited to this structure.

1 and 2 are examples, and the present invention is not limited to these.

(Middle layer)
The laminated optical glass according to one embodiment of the present invention is preferably laminated with an intermediate layer of an optical film in a laminated glass as shown in FIG. At this time, after laminating the intermediate layer on both surfaces of the optical film to form a laminate composed of the optical film and the intermediate layer, the laminate may be pressure-bonded with two sheets of glass to produce a laminated glass. .

At this time, the intermediate layer is interposed between the glass and the optical film and serves to bond and fix the glass and the optical film. Typically, the laminated glass has a configuration in which an infrared shielding film is sandwiched between two sets of intermediate layers and glass so that the intermediate layers face each other. The constituent materials of the two intermediate layers may be the same or different.

The intermediate layer is preferably a sheet made of a resin such as polyvinyl butyral or ethylene-vinyl acetate. Specifically, plastic polyvinyl butyral (manufactured by Sekisui Chemical Co., Ltd., Mitsubishi Monsanto Kasei Co., Ltd.), ethylene-vinyl acetate copolymer (manufactured by DuPont Co., Ltd., duramin by Takeda Pharmaceutical Co., Ltd.), modified ethylene-acetic acid A vinyl copolymer (Mersen (registered trademark) G manufactured by Tosoh Corporation) or the like can be used.

This intermediate layer contains, for example, stabilizers, surfactants, ultraviolet absorbers, flame retardants, antistatic agents, antioxidants, thermal stabilizers, lubricants, fillers, coloring, adhesion modifiers, and the like as additives. It can also be made. In particular, when used for window sticking, the addition of an ultraviolet absorber is effective for suppressing deterioration of the optical film due to ultraviolet rays.

The film thickness of the interlayer film used for the laminated glass is not particularly limited, but is preferably 100 to 1000 μm, more preferably from the viewpoint of the minimum penetration resistance and economy required for the laminated glass. The thickness is 100 to 750 μm, more preferably 200 to 500 μm, particularly preferably 300 to 400 μm, and most preferably 350 to 450 μm.

Further, the intermediate layer according to the present invention can be previously provided as an adhesive layer on the optical film. As such a configuration, in particular, in the configuration of the optical laminate as shown in FIG. 2, after an adhesive layer as an intermediate layer is disposed on at least one surface of the optical film, the optical film and the substrate are interposed via the adhesive layer. It is preferable to form an optical layered body by bonding.

The method for forming the adhesive layer on the optical film is not particularly limited. For example, after preparing a pressure-sensitive adhesive coating solution containing the above pressure-sensitive adhesive, it is coated on the optical film using a wire bar or the like, dried and bonded. For example, a method for producing an optical film with a layer can be used.

In the adhesive layer for bonding the optical reflection film and the substrate, the optical film is preferably installed on the incident surface side of the light beam (for example, sunlight, heat rays, etc.). In addition, it is preferable to sandwich an optical film, which is a kind of optical film according to an embodiment of the present invention, between a window glass and a substrate because it can be sealed from surrounding gas such as moisture and has excellent durability. In addition, it is preferable to install an infrared shielding film, which is an optical film according to an embodiment of the present invention, outdoors or on the outside of a vehicle (for external application) because good environmental durability can be obtained.

As the applicable adhesive layer forming material, a known adhesive can be used. The adhesive is not particularly limited, and for example, an adhesive mainly composed of a photocurable resin or a thermosetting resin can be used. Moreover, as an adhesive layer forming material, an adhesive can also be used. As an adhesive, what has durability with respect to an ultraviolet-ray is preferable, and an acrylic adhesive or a silicone adhesive is more preferable. Among these, an acrylic pressure-sensitive adhesive is more preferable from the viewpoint of pressure-sensitive adhesive properties and cost. The acrylic pressure-sensitive adhesive is preferably a solvent-based acrylic pressure-sensitive adhesive (acrylic solvent-based pressure-sensitive adhesive) because the peel strength can be easily controlled. When a solution polymerization polymer is used as the acrylic solvent-based pressure-sensitive adhesive, known monomers can be used as the monomer.

This adhesive layer contains additives such as stabilizers, surfactants, UV absorbers, flame retardants, antistatic agents, antioxidants, thermal stabilizers, lubricants, fillers, coloring, adhesion modifiers, etc. It can also be made. In particular, when used for window sticking, the addition of an ultraviolet absorber is effective for suppressing deterioration of the optical film due to ultraviolet rays.

(Substrate)
The substrate is not particularly limited, but is preferably a glass substrate. Examples of the glass used for the glass substrate include inorganic glass and organic glass. The inorganic glass is not particularly limited, and examples thereof include various types of inorganic glass such as float plate glass, polished plate glass, mold plate glass, netted plate glass, lined plate glass, heat ray absorbing plate glass, and colored plate glass. Further, the organic glass is not particularly limited, and examples thereof include glass plates made of resins such as polycarbonates, polystyrenes, polymethyl methacrylates, and the like. These organic glass plates may be a laminate formed by laminating a plurality of sheet-shaped ones made of the resin.

Commercial glass can be used as the glass substrate. Although the kind of glass is not specifically limited, Usually, soda-lime silica glass is used suitably. In this case, it may be a colorless transparent glass or a colored transparent glass.

The configuration of the optical laminate is not particularly limited, but may be a configuration in which, for example, an optical film according to an embodiment of the present invention is disposed on a single substrate. Moreover, the laminated glass which consists of a structure by which the optical film which concerns on one form of this invention is arrange | positioned between two or more base | substrates may be sufficient. As an optical laminated body which concerns on one form of this invention, it is preferable that it is a laminated glass.

Here, when the optical laminate is a laminated glass having two substrates, the glass substrate on the outdoor side close to the incident light among the two substrates is preferably a colorless transparent glass. The glass substrate on the indoor side far from the incident light side is preferably green colored transparent glass, dark transparent glass, or colorless transparent glass. The green colored transparent glass preferably has ultraviolet absorption performance and infrared absorption performance. By using these, the solar radiation energy can be reflected as much as possible on the outdoor side, and the solar radiation transmittance of the laminated glass can be further reduced.

Although the green colored transparent glass is not particularly limited, for example, soda lime silica glass containing iron is preferable. An example of the green colored transparent glass is soda lime silica glass containing 0.3 to 1% by mass of total iron in terms of Fe ₂ O _{3 in} a soda lime silica base glass. Furthermore, since the absorption of light in the near-infrared region is dominated by divalent iron out of the total iron, the mass of FeO (divalent iron) is all in terms of Fe ₂ O _3. It is preferably 20 to 40% by mass of iron.

In order to impart ultraviolet absorption performance, a method of adding cerium or the like to a soda lime silica base glass can be mentioned. Specifically, it is preferable to use soda lime silica glass having substantially the following composition;
SiO ₂ : 65 to 75% by mass, Al ₂ O ₃ : 0.1 to 5% by mass, Na ₂ O + K ₂ O: 10 to 18% by mass, CaO: 5 to 15% by mass, MgO: 1 to 6% by mass, Fe ₂ O ₃ converted total iron: 0.3 to 1% by mass, CeO ₂ converted total cerium and TiO ₂ : 0.5 to 2% by mass.

Further, the dark transparent glass is not particularly limited, and for example, soda lime silica glass containing iron at a high concentration is preferably used.

In the optical layered body according to one embodiment of the present invention, the thickness of the substrate is preferably 1.5 to 3.0 mm. By setting it as such thickness, an optical laminated body becomes a more suitable thing for windows, such as a vehicle. In a laminated glass having two substrates, the indoor substrate and the outdoor substrate can have the same thickness or different thicknesses. When a laminated glass having two substrates is used for an automobile window, for example, both the indoor substrate and the outdoor substrate may be 2.0 mm thick or 2.1 mm thick. Is possible.

Further, when using laminated glass having two substrates for an automobile window, for example, the thickness of the indoor substrate is less than 2 mm and the thickness of the outdoor substrate is slightly more than 2 mm. The thickness can be reduced and the external force from the outside of the vehicle can be resisted.

The substrate may be flat or have a curved surface. In one form of this invention, it is preferable that an optical laminated body contains the base | substrate which has a curved surface. In the case of having a curved surface, wrinkles and undulations are likely to occur in the end portion of the optical film, but the optical film according to one embodiment of the present invention has a great suppression effect, so the optical film includes an optical laminate including a substrate having a curved surface. It can be preferably applied to the body.

In this specification, a curved surface refers to a surface whose curvature radius R is not infinite. The laminated glass having a curved surface means that at least a part of the laminated glass has a curved surface.

Since vehicles, particularly automobile windows, often have curved surfaces, the shape of the base is often curved.

An example of a substrate having a curved surface is a curved glass plate. The curved glass plate is obtained by bending soda-lime glass heated to a temperature equal to or higher than the softening point by a float method, and the use of a three-dimensional curved glass plate is simple.

Examples of the shape of the three-dimensionally curved base include a spherical base, an elliptical spherical base, and a base having a different radius of curvature depending on the location, such as a front glass of an automobile. The circular diameter φ of the substrate having a curved surface is not particularly limited, but is preferably 100 to 500 mm. A circular diameter φ of 100 to 500 mm is more preferable because wrinkle evaluation corresponding to curved glass with a curvature such as an automobile window can be performed. From the same viewpoint, the thickness is more preferably 100 to 300 mm.

Further, the radius of curvature R of the substrate having a curved surface is not particularly limited, but is preferably 0.1 to 3.0 m. If the radius of curvature R is greater than 0.1 m, the wrinkles of the optical film are generally less likely to occur in the mating process. From the same viewpoint, it is more preferably 0.9 to 3 m.

In this case, the optical film included in the laminated glass having two substrates is preferably provided on the concave surface side of the outdoor glass substrate.

Furthermore, three or more glass substrates can be used as necessary.

(Method for producing optical laminate)
As an example of the method for producing an optical laminate of the present invention, a method for producing a laminated glass having two substrates is described, but the present invention is not limited to this.

The optical film may be laminated glass between two substrates. The method for producing the laminated glass is not particularly limited. For example, a laminated body obtained by laminating an optical film on both sides with an intermediate layer (for example, a sheet made of polyvinyl butyral, etc.) is sandwiched between two substrates. It is preferable to include a step of manufacturing a laminated body sandwiched between and a step of joining the laminated body sandwiched between the substrates while heating. As a detailed manufacturing method, a known laminated glass manufacturing method can be appropriately used.

In general, after sandwiching an optical film between two glass substrates, heat treatment and pressure treatment (such as squeezing with a rubber roller) are repeated several times, and finally, under pressure conditions using an autoclave or the like. The method of joining by performing the heat treatment of is taken.

It is preferable to pressure-bond the laminate sandwiched between the substrates that are not in contact with the optical film while heating. Joining of the laminate sandwiched between the base and the expectation 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 for 1.0 to 1 The laminated glass can be obtained by bonding at a temperature of 100 to 150 ° C., preferably 120 to 150 ° C. under a pressure of 5 MPa, and a laminate is sandwiched between two substrates. Moreover, you may stick together using an adhesive. At this time, the time for thermocompression bonding at a temperature of 100 to 150 ° C., preferably 120 to 150 ° C. under a pressure of 1.0 to 1.5 MPa is preferably 20 to 90 minutes.

After the thermocompression bonding, there is no particular limitation on the method of cooling, and the laminated glass may be obtained by cooling while releasing the pressure as appropriate. In the present invention, after completion of thermocompression bonding, it is preferable to lower the temperature while maintaining the pressure from the viewpoint of further improving wrinkles and cracks of the obtained laminated glass. Here, decreasing the temperature while maintaining the pressure means decreasing the temperature from the internal pressure of the apparatus at the time of thermocompression bonding (preferably 150 ° C.) so that the internal pressure of the apparatus at 40 ° C. is 75 to 100% of that at the thermocompression bonding. It means to do.

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 the outside so that the internal pressure of the apparatus does not decrease as the temperature decreases is preferable. In the case of lowering the temperature while maintaining the pressure, it is preferable to heat-press at 100 to 150 ° C., preferably 120 to 150 ° C., and then cool to 40 ° C. over 1 to 5 hours.

It is preferable to include a step of releasing the pressure after the temperature is lowered with the pressure held. 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 includes a step of laminating the constituent layers of the laminated glass, a step of bonding by thermocompression bonding at a temperature of 120 to 150 ° C. under a pressure of 1.0 to 1.5 MPa, It is preferable to include a step of lowering the temperature while holding the pressure and a step of releasing the pressure.

Note that, in manufacturing an optical laminate having another configuration, for example, an optical laminate having a configuration in which an optical film according to an embodiment of the present invention is disposed on a single substrate, the substrate and the optical film are subjected to thermocompression bonding. It is common. From this, also about the optical laminated body of another structure, by using the optical film which concerns on one form of this invention, generation | occurrence | production of a wrinkle is suppressed and the optical laminated body which has the outstanding reflective performance can be obtained.

The effect of the present invention will be described using the following examples and comparative examples. However, the technical scope of the present invention is not limited only to the following examples. In the following examples, and unless otherwise specified, measurement of operation and physical properties was performed under conditions of room temperature (20 to 25 ° C.) / Relative humidity 40 to 50% RH. Further, unless otherwise specified, “%” and “part” mean “% by mass” and “part by mass”, respectively.

<Production of optical film>
(Example 1)
(Production of polyester chip)
Take 100 parts of dimethyl terephthalate, 70 parts of ethylene glycol, and 0.07 part of calcium acetate monohydrate in a reactor, heat up and evaporate methanol to conduct transesterification, and take about 4 and a half hours after starting the reaction. The temperature was raised to 230 ° C. to substantially complete the transesterification reaction. Next, 0.04 part of phosphoric acid and 0.035 part of antimony trioxide were added and polymerized in accordance with a conventional method. That is, the reaction temperature was gradually raised to finally 280 ° C., while the pressure was gradually reduced to finally 0.05 mmHg. After 4 hours, the reaction was completed, and chips were obtained according to a conventional method to obtain polyester chips. This polyester chip was a polyethylene terephthalate chip.

(Production of polyester film substrate)
The polyester chip was used as a raw material and melt-extruded by a melt extruder to obtain an amorphous sheet. Subsequently, the sheet was coextruded on a cooled casting drum and solidified by cooling to obtain a non-oriented sheet. Next, the obtained non-oriented sheet was stretched 3.6 times in the longitudinal direction at 90 ° C. Furthermore, a water-based easy-adhesion coating solution (undercoat layer coating solution) was applied to both surfaces of the sheet after longitudinal stretching at a coating amount of 5 g / m ^{2 on} each surface. Furthermore, the sheet after application of the water-based easy-adhesion coating solution is subjected to a preheating step in the tenter and is stretched 4 times in the transverse direction at 90 ° C., and then subjected to heat treatment at 190 ° C. for 10 seconds, with a total thickness of 50 μm A polyester film substrate having an aqueous easy-adhesive resin coating layer (undercoat layer) on both sides was obtained. Here, the water-based easy-adhesion resin used for the water-based easy-adhesion coating solution was a water-soluble polyester resin.

(Preparation of coating solution 1 for high refractive index layer)
After adding 2 parts by mass of pure water to 0.5 parts by mass of 15.0% by mass of titanium oxide sol (SRD-W, volume average particle diameter: 5 nm, rutile titanium dioxide particles, manufactured by Sakai Chemical Industry Co., Ltd.), 90 Heated to ° C. Next, 0.5 parts by mass of an aqueous silicic acid solution (sodium silicate 4 (manufactured by Nippon Chemical Industry Co., Ltd.) diluted with pure water so that the SiO ₂ concentration becomes 0.5 mass%) was gradually added. Then, heat treatment was performed at 175 ° C. for 18 hours in an autoclave, and after cooling, the solution was concentrated with an ultrafiltration membrane, whereby a titanium dioxide sol (hereinafter referred to as SiO ₂₎ having a solid content concentration of 6% by mass attached to the surface. , Silica-attached titanium dioxide sol) (volume average particle size: 9 nm).

48 mass parts of 1.92 mass% citric acid aqueous solution is added with respect to 113 mass parts of 20 mass% silica adhesion titanium dioxide sol obtained in this way, and 8 mass% polyvinyl alcohol aqueous solution (made by Kuraray Co., Ltd. 113 parts by mass of PVA-117, polymerization degree 1700, saponification degree: 97.5-99 mol%) was added and stirred, and finally 5% by mass of a surfactant aqueous solution (SOFTAZOLINE® LSB-R, Kawasaki) 0.4 parts by mass of Ken Fine Chemical Co., Ltd.) was added to prepare a coating solution 1 for a high refractive index layer.

(Preparation of coating solution 1 for low refractive index layer)
10 mass% acidic colloidal silica aqueous dispersion (Snowtex (registered trademark) OXS, primary particle size: 5.4 nm, manufactured by Nissan Chemical Industries, Ltd.) 31 mass parts was heated to 40 ° C., and 3 mass% boric acid. 3 parts by weight of an aqueous solution was added, and further 6 parts by weight of a polyvinyl alcohol aqueous solution (PVA-224, polymerization degree: 2400, saponification degree: 87 mol%, manufactured by Kuraray Co., Ltd.), 20 parts by weight, 6% by weight of water-dispersible acrylic Resin dispersion 1 (AE120A, particle size = 55 nm, manufactured by Etec Co., Ltd.) 6 parts by mass, and 5% by mass of a surfactant aqueous solution (Softazoline (registered trademark) LSB-R, manufactured by Kawaken Fine Chemical Co., Ltd.) 1 part by mass Were added in this order at 40 ° C. to prepare a coating solution 1 for a low refractive index layer.

(Method for forming reflective layer)
Using a slide hopper coating apparatus capable of 60-layer coating, a high refractive index layer coating liquid 1 and a low refractive index layer coating liquid 2 are kept at 40 ° C. and heated to 40 ° C., and a polyester film base having a width of 160 mm On the material, the lowermost layer and the uppermost layer are low refractive index layers, and the low refractive index layer and the low refractive index layer are alternately disposed so that the low refractive index layer and the lower refractive index layer are alternately arranged. A total of 53 layers were simultaneously applied so that the low refractive index layer was 150 nm and the high refractive index layer was 130 nm. Immediately after application, cold air of 10 ° C. was blown to set (thickening). After completion of the setting (thickening), hot air of 60 ° C. was blown and dried to produce an optical film 1 having a dielectric multilayer reflective layer (7.5 μm) consisting of a total of 53 layers.

(Examples 2 to 7, Comparative Examples 1 and 2)
Each substrate was prepared in the same manner as in Example 1 except that the thickness of the polyester film and the heat treatment temperature were appropriately changed as each substrate. Also, low refractive index layer coating solutions 2 to 9 prepared in the same manner as the low refractive index layer coating solution 1 except that the amount of the water-dispersible acrylic resin dispersion was changed were prepared. Then, Example 1 is used except that the low refractive index layer coating liquids 2 to 9 are used in place of the low refractive index layer coating liquid 1 on each substrate, and that the number of reflection layers laminated is appropriately changed. Similarly, each reflective layer was formed, and optical films 2 to 7 according to Examples 2 to 7 and optical films 8 and 9 according to Comparative Examples 1 and 2 were produced. Here, the storage elastic modulus (E ′) at a high temperature of the reflective layer can be changed by the addition amount of the water-dispersible acrylic resin dispersion, and the storage elastic modulus (E ′) at a high temperature can be reduced by reducing the addition amount. Can be increased. Moreover, the storage elastic modulus (E ') in high temperature can be reduced by increasing the addition amount. Table 1 below shows the amount of the water-dispersible acrylic resin dispersion 1, the characteristics of each optical film, and the performance evaluation results.

<Production of optical laminate>
A curved circular lens glass (circular lens diameter φ150 mm, glass curvature radius R200 mm) serving as the indoor side glass, a sheet of polyvinyl butyral having a thickness of 380 μm serving as the intermediate layer on the indoor side, the optical film 1, and the intermediate layer on the outdoor side After laminating a sheet made of polyvinyl butyral having a thickness of 380 μm and a curved circular lens glass (circular lens diameter φ150 mm, glass radius of curvature R200 mm) as an outdoor glass in this order, and removing an excess portion protruding from the edge portion of the glass The laminated glass 1 was produced as an optical laminate using the optical film of Example 1 by heating at 150 ° C. for 30 minutes, pressurizing and deaerating to perform bonding treatment. Here, the lamination is performed by pressing a sheet made of polyvinyl butyral serving as an intermediate layer on the indoor side, an optical film, and a sheet consisting of polyvinyl butyral serving as the intermediate layer on the outdoor side with a laminator to form a laminate. The laminate was sandwiched between a curved circular lens glass serving as an indoor glass and a curved circular lens glass serving as an outdoor glass. The optical film was arranged so that the base material was on the indoor side.

Further, in the same manner as in the production of the laminated glass 1, instead of the optical film 1, the optical films 2 to 7 according to Examples 2 to 7 and the optical films 8 and 9 according to Comparative Examples 1 and 2 were used. 2 to 9 were produced.

<Evaluation>
(Reflective layer thickness measurement)
The thickness of the reflective layer was determined by cutting a tom of the produced optical film, and using an electron microscope (FE-SEM, S-5000H type, manufactured by Hitachi, Ltd.) for the cross section. The number of fields was selected and observed so that a 1 cm length could be observed under the conditions. Next, the obtained image was digitized and subjected to image processing for adjusting the contrast. Then, the film thickness was measured for each layer, and the film thickness of the reflective layer was obtained. In addition, the film thickness was made into the average value of the measurement result of 1000 places.

(Preparation of reflective layer measurement sample)
Only the reflective layer was dissolved in a mixed solvent of ethanol and water, and the solution was recovered. Subsequently, the solution was formed on a release film so that the film thickness after drying was 4 μm, and a single film obtained by peeling the release film was used as a sample for measuring a reflective layer. The thermal contraction rate and the storage elastic modulus (E ′) at a high temperature of this reflective layer measurement sample were measured. In this measurement, in the thickness range of the reflective layer of each optical film, it was confirmed that the values of the storage elastic modulus (E ′) and the heat shrinkage rate of the reflective layer measurement sample did not change even when the thickness changed. Therefore, the reflective layer measurement samples for all the optical films were prepared with a film thickness of 4 μm. In the measurement of the storage elastic modulus (E ′) and the heat shrinkage rate at the following high temperatures, the measurement results using the reflection layer measurement sample were handled as the measurement results of the reflection layer.

(Measurement of loss factor (tan δ) of optical film and substrate)
Each optical film was prepared. Moreover, the base material similar to the base material used for each optical film preparation was prepared, respectively.

Based on JIS K7244-1: 1998, the storage elastic modulus (E ′) and loss elastic modulus (E ″) of the optical film and substrate are measured based on a dynamic viscoelasticity automatic measuring instrument (DDV-01GP manufactured by A & D Corporation). ), Measuring from 25 ° C. to 250 ° C. in tension mode, frequency 10 Hz, heating rate 5 ° C./min, minimum tension / compression ratio 49 mN, tension / compression force gain 1.0, and force amplitude initial value 49 mN. Next, the loss factor (tan δ) was obtained by calculating E ″ / E ′ from the obtained results. The measurement was performed in the machine direction of the film, that is, the longitudinal direction of the optical film and the base material and the direction orthogonal thereto, and the average value was used as the evaluation result. Table 1 shows the value of the loss factor (tan δ) at 150 ° C. in each example and comparative example.

(Measurement of storage elastic modulus (E ′) of substrate and reflective layer at high temperature)
A substrate similar to the substrate used for the production of each optical film was prepared. Moreover, the reflection layer measurement sample corresponding to the reflection layer used for each optical film was prepared, respectively.

The storage elastic modulus (E ′) of the substrate and the reflection layer measurement sample was evaluated using the same method as the method for evaluating the storage elastic modulus (E ′) in the measurement of the loss factor (tan δ). The measurement of the substrate was performed in the machine direction of the film, that is, the longitudinal direction of the substrate and the direction orthogonal thereto, and the average value was used as the evaluation result. The reflective layer measurement sample was measured in two arbitrary directions orthogonal to each other, and the average value was taken as the evaluation result. From the obtained value, the absolute value of the difference in storage elastic modulus (E ′) between the substrate and the reflective layer was calculated. Table 1 shows the value of the storage elastic modulus (E ′) at 150 ° C. of each Example and Comparative Example, and the absolute value of the difference in the storage elastic modulus (E ′) between the substrate and the reflective layer.

(Measurement of thermal shrinkage of base material and reflective layer)
Each base material similar to the base material used for preparation of each optical film was prepared. Moreover, each reflective layer measurement sample corresponding to the reflective layer used for each optical film was prepared.

After the substrate and the reflective layer measurement sample are stored for 24 hours in an environment of a temperature of 23 ° C. and a relative humidity of 55% RH, two marks are made at intervals of 100 mm in the width direction, and between the two marks in an unloaded state The distance L1 was measured using a microscope or the like. Subsequently, the sample was hung in an oven at 150 ° C. and left for 30 minutes. After 30 minutes, the sample was taken out of the oven and stored again for 24 hours in an environment at a temperature of 23 ° C. and a relative humidity of 55%. Next, the distance L2 between the two marks on the unloaded sample was measured using a microscope or the like. From the measured distances L1 and L2, the thermal contraction rate of the sample was calculated by the following formula;
Thermal contraction rate (%) = ((L1-L2) / L1) × 100
The measurement of the substrate was performed in the machine direction of the film, that is, the longitudinal direction of the substrate and the direction orthogonal thereto, and the average value was used as the evaluation result. The reflective layer measurement sample was measured in two arbitrary directions orthogonal to each other, and the average value was taken as the evaluation result. Table 1 shows the values of the heat shrinkage rate of each example and comparative example over time at 150 ° C. for 30 minutes.

<Evaluation of wrinkles>
Using each optical film, each optical laminate was prepared in the same manner 100 times, and the frequency and generation position of wrinkles generated during heating at 150 ° C. for 30 minutes were visually evaluated according to the following criteria. In addition, the evaluation judged that ○ or more is a practical characteristic. The results are shown in Table 1;
A: Wrinkles are not generated at all.
○: Occurrence frequency is 5 times or less, and all occurrence positions are present at positions less than 10 mm at the end.
Δ: Occurrence frequency is 5 times or less, and there is an occurrence position where the occurrence position reaches a position of 10 mm or more at the end,
X: Occurrence frequency exceeds 5 times, and the occurrence position reaches a position where the end portion is 10 mm or more.

<Evaluation of infrared reflectance performance>
About each optical laminated body manufactured using each optical film, the center part and edge part of glass are cut out to 30 mm square, and the heat ray (infrared) reflectance is measured using a spectrophotometer V700 (manufactured by JASCO Corporation). Then, the wavelength region from 800 to 2000 nm was measured, and the average infrared reflectance of the region was calculated. From the obtained measurement results, a difference in heat ray transmittance between the center portion and the end portion was calculated and evaluated according to the following criteria. In addition, the evaluation judged that ○ or more is a practical characteristic. The results are shown in Table 1. ;
A: Heat ray (infrared) reflectance difference between the center and the end is 1% or less,
○: Heat ray (infrared) reflectance difference between the center and the end is more than 1% and 2% or less,
Δ: Heat ray (infrared) reflectance difference between the center and the end is more than 2% and not more than 3%.
X: The heat ray (infrared ray) reflectance difference between the center portion and the end portion exceeds 3%.

Here, the favorable infrared reflection performance of the optical laminate means that the infrared reflection performance of the optical film is good.

From the results of Table 1, it was shown that the optical film of the present invention was less likely to be wrinkled during heat processing and superior in infrared reflection performance than the optical film of the comparative example.

This application is based on Japanese Patent Application No. 2015-127799 filed on June 25, 2015, the disclosure of which is incorporated by reference in its entirety.

Claims

A substrate, and a reflective layer;
The base material and the reflective layer have an absolute value of a difference in storage elastic modulus (E ′) at 150 ° C. (measuring condition: JIS K7244-1: 1998, tensile mode, heating rate 5 ° C./min, frequency 10 Hz). Is 0.05 GPa or more,
Loss coefficient at 150 ° C. (tan δ) (measurement conditions: JIS K7244-1: 1998 compliant, tensile mode, temperature rising rate 5 ° C./min, frequency 10 Hz) is 0.12 to 0.20.
Optical film.
The substrate has a loss coefficient (tan δ) at 150 ° C. (measurement conditions: JIS K7244-1: 1998 compliant, tensile mode, temperature rising rate 5 ° C./min, frequency 10 Hz) of 0.12 to 0.45. The optical film according to claim 1.
The base material had a storage elastic modulus (E ′) at 150 ° C. (measurement conditions: JIS K7244-1: 1998 compliant, tensile mode, heating rate 5 ° C./min, frequency 10 Hz) of 0.01 GPa or more. And the optical film of Claim 1 or 2 smaller than the value of the storage elastic modulus (E ') in 150 degreeC of the said reflection layer.
The optical film according to any one of claims 1 to 3, wherein the base material has a heat shrinkage rate of 2.0 to 10.0% after being left for 30 minutes in an environment of 150 ° C.
The optical film according to any one of claims 1 to 4, wherein the substrate is a resin film.
The reflective layer has a storage elastic modulus (E ′) at 150 ° C. (measuring condition: JIS K7244-1: 1998 compliant, tensile mode, heating rate 5 ° C./min, frequency 10 Hz) of 2.00 GPa to 13.2. The optical film according to any one of claims 1 to 5, which has a pressure of 50 GPa.
The optical film according to any one of claims 1 to 6, wherein the reflective layer has a thermal shrinkage of 0.5 to 5.0% after being left for 30 minutes in an environment of 150 ° C.
The optical film according to any one of claims 1 to 7, wherein the reflective layer is a dielectric multilayer film in which a high refractive index layer and a low refractive index layer are alternately laminated.
The optical film according to any one of claims 1 to 8, wherein at least one of the high refractive index layer and the low refractive index layer contains a water-soluble binder resin.
The optical film according to any one of claims 1 to 9, wherein the thickness of the base material occupies a ratio of 86.5% or more in the total thickness of the optical film.
The optical film according to any one of claims 1 to 10, wherein the reflective layer is an infrared reflective layer.
An optical laminate comprising the optical film according to any one of claims 1 to 11 and at least one substrate.
The optical laminate according to claim 12, wherein the substrate has a curved surface.
The optical laminate according to claim 12 or 13, which is a laminated glass.