WO2024024467A1

WO2024024467A1 - Liquid composition and optical film

Info

Publication number: WO2024024467A1
Application number: PCT/JP2023/025399
Authority: WO
Inventors: 学伊藤
Original assignee: 日本ゼオン株式会社
Priority date: 2022-07-28
Filing date: 2023-07-10
Publication date: 2024-02-01

Abstract

This liquid composition comprises: 70 to 100 parts by weight of a nonionic surfactant having a number-average molecular weight greater than 500; 0 to 30 parts by weight of a component having a number-average molecular weight of 100 to 500; and water.

Description

Liquid composition and optical film

The present invention relates to a liquid composition and an optical film.

By forming the optical film into a film having a multilayer structure, various functions can be imparted. Such a multilayer structure may be formed by a method including a step of applying a liquid composition to the surface of a film serving as a base material. A surfactant may be blended into the liquid composition for the purpose of reducing alignment defects of the liquid crystalline compound blended or for the purpose of making the layer of the liquid composition function as an antistatic layer (Patent Documents 1 to 3). (See 3).

JP2017-203168A (corresponding foreign publication: US Patent Application Publication No. 2018/0002459) International Publication No. 2016/136231 (corresponding foreign publication: US Patent Application Publication No. 2017/0351147) Japanese Patent Application Publication No. 2011-184676

In recent years, there has been a demand for aqueous liquid compositions containing water as a medium because of their low environmental impact. A layer of the liquid composition is formed by coating the surface of the film serving as a base material with an aqueous liquid composition, and this layer is dried to remove water, thereby forming a cured layer of the liquid composition. An optical film having a multilayer structure can be obtained.
When a heating dryer is used to dry a layer of a liquid composition, resinous stains may adhere to the inside of the heating dryer. Dirt inside the heat drying device causes contamination of optical films that require high quality. Therefore, the optical film production line may be frequently stopped in order to clean the dirt inside the heating dryer. Therefore, there is a need for a liquid composition that generates less stain when dried.
Further, in the optical film, the cured layer of the liquid composition is required to have a good surface condition.
Therefore, there is a need for a liquid composition that produces a cured layer with a small amount of dirt and a good surface condition when dried; and an optical film that includes a cured layer of such a liquid composition.

The inventors of the present invention have made extensive studies to solve the above problems. As a result, it was discovered that the resinous stains occurring inside the heat drying device were derived from the surfactant contained in the liquid composition. As a result of further studies based on this knowledge, the present inventor found that a nonionic surfactant containing a nonionic surfactant with a number average molecular weight of more than 500 and water has a number average molecular weight relative to the weight of the nonionic surfactant. The inventors have discovered that the above-mentioned problems can be solved by a liquid composition in which the weight of the components is 100 or more and 500 or less, and the present invention has been completed.
That is, the present invention provides the following.

[1] 70 parts by weight or more and 100 parts by weight or less of a nonionic surfactant having a number average molecular weight of more than 500;
0 parts by weight or more and 30 parts by weight or less of a component having a number average molecular weight of 100 or more and 500 or less;
A liquid composition containing water.
[2] The liquid composition according to [1], wherein the nonionic surfactant has a number average molecular weight of 550 or more.
[3] The liquid composition according to [1] or [2], which contains the nonionic surfactant in an amount of 0.02% by weight or more and 0.10% by weight or less.
[4] The liquid composition according to any one of [1] to [3], further comprising polyurethane and silica particles.
[5] An optical film comprising a base material and a cured layer of the liquid composition according to any one of [1] to [4] provided on the main surface of the base material.
[6] The optical film according to [5], wherein the base material is made of a cycloolefin resin.

According to the present invention, it is possible to provide a liquid composition that produces a cured layer with a small amount of dirt and a good surface condition when dried; and an optical film that includes a cured layer of such a liquid composition.

Hereinafter, the present invention will be described in detail by showing embodiments and examples. However, the present invention is not limited to the embodiments and examples shown below, and may be implemented with arbitrary changes within the scope of the claims of the present invention and equivalents thereof. The components of the embodiments shown below can be combined as appropriate.

In the following description, a "long" film refers to a film having a length of 5 times or more, preferably 10 times or more, of the width, and specifically a roll A film that is long enough to be rolled up into a shape for storage or transportation. The upper limit of the length of the film is not particularly limited, and may be, for example, 100,000 times or less the width.

In the following description, the in-plane retardation Re of a layer is a value expressed by Re=(nx-ny)×d, unless otherwise specified. Further, the retardation Rth in the thickness direction of the layer is a value expressed by Rth=[{(nx+ny)/2}-nz]×d, unless otherwise specified. Here, nx represents the refractive index in the direction perpendicular to the thickness direction of the layer (in-plane direction) and giving the maximum refractive index. ny represents the refractive index in the in-plane direction of the layer and perpendicular to the nx direction. nz represents the refractive index in the thickness direction of the layer. d represents the layer thickness. The measurement wavelength is 590 nm unless otherwise specified.

[1. Liquid composition]
[1.1. Overview of liquid composition]
The liquid composition according to one embodiment of the present invention is
70 parts by weight or more and 100 parts by weight or less of a nonionic surfactant having a number average molecular weight of more than 500;
0 parts by weight or more and 30 parts by weight or less of a component having a number average molecular weight of 100 or more and 500 or less;
including water.
Hereinafter, a nonionic surfactant having a number average molecular weight of more than 500 is also referred to as a nonionic surfactant (N), and a component having a number average molecular weight of 100 to 500 is also referred to as a component (L).
In other words, the liquid composition according to one embodiment of the present invention may be the following liquid composition (1) or (2).
(1) A liquid composition containing water and a nonionic surfactant (N) having a number average molecular weight of more than 500, without containing a component having a number average molecular weight of 100 or more and 500 or less.
(2) 70 parts by weight or more and less than 100 parts of a nonionic surfactant (N) with a number average molecular weight of more than 500; A liquid composition containing a certain ingredient and water.
The liquid composition according to the present embodiment is less likely to cause volatile stains when it is applied to a substrate to form a layer of the liquid composition, and the layer of the liquid composition is heated and dried to cure it. Therefore, contamination of the heating drying device is reduced, and the frequency of cleaning of the device can be reduced. As a result, the time for stopping the production line can be shortened, and a film including a cured layer of the liquid composition can be efficiently produced.
Further, in the liquid composition according to the present embodiment, the components contained therein can be well dispersed in the liquid composition, and the cured layer of the liquid composition can have a good surface condition.

[1.2. Nonionic surfactant (N)]
A nonionic surfactant usually means a surfactant having a hydrophilic group that does not ionize in water.
Examples of nonionic surfactants include acetylene surfactants containing an acetylene structure; compounds having an ester structure of fatty acid and polyhydric alcohol; compounds having a polyoxyalkylene structure; and the like. The nonionic surfactant may or may not have a fluorine atom, but it is preferable that it does not have a fluorine atom because it has a small burden on the environment.

Examples of specific product names of nonionic surfactants include "Surfynol Series" manufactured by Air Products and Chemicals; "Dynor 607" manufactured by Nissin Chemical Co.; "Floren D-90" and "Polyflow" manufactured by Kyoeisha Chemical KL-900"; "SN Wet 980", "SN Wet 984" manufactured by Sannopco; "Nukol 170", "Nukol 85", "Nukol 3-85" manufactured by Nippon Nyukazai; "NIKKOL" manufactured by Nikko Chemicals ” series (BT-7, BT-9, BT-12, BL-4.2, BL-9EX, BB-10, BB-20, BC-7, BC-15, BO-7V, BO-10V, SG -DTD620, SG-DTD630, SG-G2424, PBC-33, BPS-20); One type of nonionic surfactant may be used alone, or two or more types may be used in combination in any ratio.

The nonionic surfactant (N) usually has a number average molecular weight of more than 500, preferably 550 or more, and the upper limit is not particularly limited, but may be 15,000 or less.
Here, the nonionic surfactant (N) may be a compound having no molecular weight distribution, may be an oligomer, or may be a polymer. The number average molecular weight of the nonionic surfactant (N) can be measured using gel permeation chromatography (GPC). The measurement conditions may be as follows.
Injection sample: 0.1% by weight tetrahydrofuran (THF) solution Column temperature: 40°C
Developing solvent: THF
Detector: Differential refractometer (RI)
Standard material: polystyrene

The HLB value of the nonionic surfactant (N) is not particularly limited, but may be, for example, 7 or more and, for example, 16 or less. The HLB value can be determined, for example, by the Griffin method.

The liquid composition of the present embodiment may contain one kind of nonionic surfactant (N), or two or more kinds thereof in any ratio.

The liquid composition of this embodiment may or may not contain a surfactant other than the nonionic surfactant (N).

The content of the nonionic surfactant (N) in the liquid composition of the present embodiment is usually more than 0% by weight, preferably 0.02% by weight or more, based on 100% by weight of the liquid composition, Preferably it is 0.10% by weight or less. When the liquid composition contains multiple types of nonionic surfactants (N), the content rate means the total content of the multiple types of nonionic surfactants (N) included.

[1.3. Ingredients (L)]
The component (L) having a number average molecular weight of 100 or more and 500 or less may or may not be contained in the liquid composition.
The presence of component (L) in the liquid composition and the weight ratio of the nonionic surfactant (N) to component (L) can be confirmed by GPC. As the conditions for GPC, the same conditions as those for measuring the number average molecular weight of the nonionic surfactant (N) may be used.

The liquid composition may contain only one kind of component (L), or may contain two or more kinds in any ratio.

Component (L) may be a substance having no molecular weight distribution, may be an oligomer, or may be a polymer.

In the liquid composition, the weight ratio of the nonionic surfactant (N) to the component (L) is such that the nonionic surfactant (N) is usually 70 parts by weight or more and 100 parts by weight or less, and the component (L) is usually 0 parts by weight or more and 30 parts by weight or less. Component (L) being 0 parts by weight or more means that component (L) is 0 parts by weight (that is, it does not contain component (L)) or more than 0 parts by weight. Component (L) may be 0 parts by weight, for example, 1 part by weight or more, for example, 5 parts by weight or more. The nonionic surfactant (N) is usually 100 parts by weight or less, and may be less than 100 parts by weight, for example. However, the total weight of the nonionic surfactant (N) and component (L) contained in the liquid composition is 100 parts by weight.
Here, when the liquid composition contains multiple types of nonionic surfactants (N) and/or when the liquid composition contains multiple types of components (L), the nonionic surfactant The weight ratio of the agent (N) to the component (L) is the ratio of the total weight of the nonionic surfactant to the total weight of the component (L).

The weight ratio of the nonionic surfactant (N) to the component (L) can be determined by measuring GPC of the liquid composition. Specifically, GPC of the liquid composition is measured, and the area of all peaks is set as 100%, and based on the peak area of the nonionic surfactant (N) and the peak area of the component (L), the The content weight ratio can be determined.

[1.4. water]
The liquid composition of this embodiment usually contains water. Water can be a solvent or dispersion medium that dissolves or disperses the components contained in the liquid composition. The content of water contained in the liquid composition is determined, for example, from the viewpoint of keeping the liquid composition within a viscosity range suitable as a coating liquid used in a coating method, and from the viewpoint of adjusting the thickness of the cured layer of the liquid composition to a desired thickness. It can be set as appropriate from the viewpoint of The content of water contained in the liquid composition is not particularly limited, but is, for example, 90% by weight or more, such as 91% by weight or more, such as 92% by weight or more, such as 99% by weight, based on 100% by weight of the liquid composition. The content is, for example, 98% by weight or less, and is, for example, 92% by weight or more and 98% by weight or less.

The liquid composition can be used in a coating method as an aqueous coating liquid containing water as a solvent or dispersion medium. Water-based coating fluids have a small environmental impact when dried.

[1.5. Other ingredients]
The liquid composition of this embodiment may further contain an arbitrary component in addition to the nonionic surfactant (N), water, and an arbitrary component (L).

The liquid composition may contain a polymer. Examples of polymers that the liquid composition may include include polyurethanes, acrylic polymers, polyesters, polyvinyl acetates, polyvinyl chlorides, and polyolefins. These polymers may be homopolymers or copolymers. Further, the polymer may be a prepolymer having a polymerizable group that can be further polymerized. The liquid composition may contain one kind of polymer alone, or two or more kinds of polymers in any ratio.

The liquid composition preferably contains polyurethane. A primer layer can be provided on a substrate using a liquid composition containing polyurethane. By providing a primer layer between the base material and a functional layer such as a polarizer layer, the adhesiveness between the base material and the functional layer can be improved.

As the polyurethane, for example, a polyurethane obtained by reacting (i) a component containing an average of two or more active hydrogens per molecule and (ii) a polyisocyanate component can be used.
In addition, as polyurethane, for example, an isocyanate group-containing prepolymer obtained by subjecting component (i) and component (ii) to a urethanization reaction is chain-extended using a chain extender, and water is added to form a dispersion. A polyurethane produced by the following method can be used. The prepolymer described above can be obtained by subjecting the component (i) and the component (ii) to a urethane reaction under conditions where an excess of isocyanate groups is present. Further, the urethanization reaction described above can be carried out in an organic solvent that is inert to the reaction and has a high affinity for water. Furthermore, the prepolymer may be neutralized before chain extension. Further, as a method for extending the chain of the isocyanate group-containing prepolymer, there may be mentioned a method of reacting the isocyanate group-containing prepolymer with a chain extender in the presence of a catalyst if necessary. At this time, water, water-soluble polyamines, glycols, etc. can be used as the chain extender.

The component (i) is preferably one having a hydroxyl active hydrogen, such as a compound having an average of two or more hydroxyl groups in one molecule.

A specific example of component (i) is polyether polyol.

Examples of polyether polyols include alkylene oxide adducts of polyol compounds; ring-opening (co)polymers of alkylene oxide and cyclic ethers (such as tetrahydrofuran); polyethylene glycol, polypropylene glycol, ethylene glycol-propylene glycol copolymers, 1 , 4-butanediol copolymer; glycols such as glycol, polytetramethylene glycol, polyhexamethylene glycol, polyoctamethylene glycol; and the like.

Examples of polyol compounds that can be used in the production of polyether polyols include ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 2,3-butylene glycol, 1, 4-butylene glycol, 1,5-pentanediol, neopentyl glycol, 1,6-hexane glycol, 2,5-hexanediol, dipropylene glycol, 2,2,4-trimethyl-1,3-pentanediol, tri Cyclodecanedimethanol, 1,4-cyclohexanedimethanol, 2,2-dimethylpropanediol, 1,4-butanediol, 1,6-hexanediol, 1,8-octamethylenediol, glycerin, trimethylolpropane, etc. Can be mentioned.

One type of component (i) may be used alone, or two or more types may be used in combination in any ratio.

Examples of the component (ii) (ie, polyisocyanate component) to be reacted with the component (i) include compounds containing an average of two or more isocyanate groups in one molecule. This compound may be an aliphatic compound, an alicyclic compound, or an aromatic compound.
The aliphatic polyisocyanate compound is preferably an aliphatic diisocyanate having 1 to 12 carbon atoms, such as hexamethylene diisocyanate, 2,2,4-trimethylhexane diisocyanate, hexane diisocyanate (HDI), and the like.
The alicyclic polyisocyanate compound is preferably an alicyclic diisocyanate having 4 to 18 carbon atoms, such as 1,4-cyclohexane diisocyanate, methylcyclohexylene diisocyanate, isophorone diisocyanate (IPDI), dicyclohexylmethane diisocyanate (HMDI), etc. can be mentioned.
Examples of the aromatic polyisocyanate include tolylene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate, and xylylene diisocyanate.

One type of these components (ii) may be used alone, or two or more types may be used in combination in any ratio.

The above-mentioned components (i) and (ii) may be appropriately selected and used depending on the use of the optical film including the cured layer of the liquid composition of the present embodiment. Among these, as component (i), it is preferable to use one having a bond that is difficult to hydrolyze, and specifically, polyether polyol is preferable. A polyurethane using a polyether polyol as the component (i) is called a "polyether polyurethane." Polyether polyurethane has ether bonds that are difficult to hydrolyze. Therefore, since polyurethane is difficult to deteriorate in a high humidity environment, it is possible to effectively suppress a decrease in adhesiveness in a high humidity environment.

Furthermore, these polyurethanes may contain an acid structure in their molecular structure. Since polyurethane containing an acid structure can be dispersed in water even with a small amount of surfactant, it is expected to improve the water resistance of the cured layer of the liquid composition. This is called a self-emulsifying type, which means that polyurethane particles can be dispersed and stabilized in water just by molecular ionicity even without a surfactant. Furthermore, since polyurethane containing an acid structure does not require or requires a small amount of surfactant, it has excellent adhesion to the base material and can maintain high transparency.

Examples of the acid structure include acid groups such as carboxyl group (-COOH) and sulfo group (-SO ₃ H). Further, the acid structure may be present in the side chain or at the end of the polyurethane. One type of acid structure may be used, or two or more types may be used in combination in any ratio.

The amount of acid structure is preferably 20 mgKOH/g or more, more preferably 25 mgKOH/g or more, and preferably 250 mgKOH/g or less, more preferably 150 mgKOH/g or less, in terms of acid value in the liquid composition. By setting the acid value to be equal to or higher than the lower limit of the above range, the water dispersibility of the polyurethane can be improved. Further, by setting the amount to be below the upper limit, the water resistance of the cured layer of the liquid composition can be improved.

Examples of the method for introducing an acid structure into polyurethane include a method in which a carboxyl group is introduced in advance into a polyether polyol by replacing part or all of the component (i) with dimethylolalkanoic acid. Examples of the dimethylol alkanoic acid used here include dimethylol acetic acid, dimethylol propionic acid, and dimethylol butyric acid. One type of dimethylolalkanoic acid may be used alone, or two or more types may be used in combination in any ratio.

In the liquid composition, it is preferable that part or all of the acid structure contained in the polyurethane be neutralized with a nonvolatile base. Because the acid structure is neutralized, even if the optical film containing the cured layer of the liquid composition has a thermal history of being exposed to high temperatures, it maintains its properties as an optical material and is compatible with any component. It is possible to bond with strong adhesive force. Further, even if the acid structure is neutralized, it is possible to disperse polyurethane particles in water even if the amount of surfactant is small.

Of the acid structures contained in polyurethane, the proportion of acid structures to be neutralized is preferably 20% or more, particularly preferably 50% or more. By neutralizing 20% or more of the acid structure, the optical film containing the cured layer of the liquid composition can maintain its properties as an optical material even if it has a thermal history of being exposed to high temperatures. , it is possible to adhere to any member with strong adhesive force.

It is preferable that the polyurethane contains a polar group in order to enable reaction with a crosslinking agent. Examples of the polar group include a methylol group, a carboxyl group, a carbonyloxycarbonyl group, an epoxy group, a hydroxyl group, an oxy group, an ester group, a silanol group, a silyl group, an amino group, a nitrile group, and a sulfo group. Among these, a methylol group, a hydroxyl group, a carboxyl group, and an amino group are preferable, a hydroxyl group and a carboxyl group are more preferable, and a carboxyl group is particularly preferable. The amount of polar groups in the polyurethane is preferably 0.0001 equivalent/1 kg or more, more preferably 0.001 equivalent/1 kg or more, and preferably 1 equivalent/1 kg or less.

As the polyurethane, those commercially available as water-based urethane resins may be used. A water-based urethane resin is a composition containing polyurethane and water, and is usually a composition in which polyurethane and optional components included are dispersed in water. Examples of water-based urethane resins include the "ADEKA BONTITER" series manufactured by ADEKA, the "OLESTAR" series manufactured by Mitsui Chemicals, the "BONDIC" series manufactured by DIC, and the "Hydran (WLS201, WLS202, etc.)" series. , "Inplanil" series manufactured by Bayer, "Poise" series manufactured by Kao, "Samplen" series manufactured by Sanyo Chemical Industries, "Superflex" series manufactured by Daiichi Kogyo Seiyaku, " NEOREZ series, Sancure series manufactured by Lubrizol, etc. can be used. Moreover, one type of polyurethane may be used alone, or two or more types may be used in combination in any ratio.

In the liquid composition, the state of the polyurethane is arbitrary, and it may be dispersed in the form of particles or dissolved in other components such as a solvent. Among these states, polyurethane is preferably dispersed in the form of particles. In this case, the average particle diameter of the polyurethane particles is preferably 0.01 μm to 0.4 μm from the viewpoint of optical properties of the optical film including the cured layer of the liquid composition.

The liquid composition may contain a crosslinking agent. In particular, when the liquid composition contains polyurethane, it is preferable to contain a crosslinking agent.
The crosslinking agent can crosslink polyurethane by reacting with a reactive group that polyurethane has to form a bond. This crosslinking can improve the mechanical strength, adhesiveness, and heat-and-moisture resistance of the cured layer of the liquid composition. Usually, crosslinking agents are contained in polyurethane, such as carboxyl groups and their anhydride groups contained as the acid structure, and hydroxyl groups remaining unreacted after the reaction of component (i) and component (ii). It can react with polar groups to form crosslinked structures.

As the crosslinking agent, for example, a compound having two or more functional groups in one molecule that can react with a reactive group of polyurethane to form a bond can be used. Among these, as the crosslinking agent, a compound having a functional group that can react with the carboxyl group or anhydride group thereof that polyurethane has is preferable.
Specific examples of crosslinking agents include epoxy compounds. Moreover, one type of crosslinking agent may be used alone, or two or more types may be used in combination in any ratio.

As the epoxy compound, a polyfunctional epoxy compound having two or more epoxy groups in one molecule can be used. Among these, the epoxy compound is preferably one that is soluble in water or can be dispersed in water to form an emulsion. If the epoxy group has water solubility or can be emulsified, when the liquid composition is a water-based resin, it improves the coating properties of the water-based resin and produces a cured layer of the liquid composition. It becomes possible to do this easily. Here, the aqueous resin refers to a composition containing a solid content such as a polymer dissolved or dispersed in an aqueous solvent such as water.

Examples of the epoxy compounds include glycols 1 such as ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, 1,6-hexane glycol, and neopentyl glycol. A diepoxy compound obtained by etherification of 1 mole of a polyhydric alcohol such as glycerin, polyglycerin, trimethylolpropane, pentaerythritol, sorbitol, etc. with 2 moles of epichlorohydrin and 2 moles or more of epichlorohydrin. Polyepoxy compounds; diepoxy compounds obtained by esterifying 1 mole of dicarboxylic acid such as phthalic acid, terephthalic acid, oxalic acid, adipic acid, etc. with 2 moles of epichlorohydrin; and the like.

More specific examples of epoxy compounds include 1,4-bis(2',3'-epoxypropyloxy)butane, 1,3,5-triglycidyl isocyanurate, 1,3-dicrycidyl-5-( γ-acetoxy-β-oxypropyl) isocyanurate, sorbitol polyglycidyl ethers, polyglycerol polyglycidyl ethers, pentaerythritol polyglycidyl ethers, diglycerol polyglycidyl ether, 1,3,5-triglycidyl (2- Examples include hydroxyethyl) isocyanurate, glycerol polyglycerol ethers, and trimethylolpropane polyglycidyl ethers.
Examples of commercially available epoxy compounds include the "Denacol (Denacol EX-521, Denacol EX-512, EX-614B, etc.)" series manufactured by Nagase ChemteX.
One type of epoxy compound may be used alone, or two or more types may be used in combination in any ratio.

The amount of the epoxy compound is usually 2 parts by weight or more, preferably 5 parts by weight or more, more preferably 8 parts by weight or more, and usually 40 parts by weight or less, preferably 35 parts by weight or less, based on 100 parts by weight of the polyurethane. Preferably it is 30 parts by weight or less. By setting the amount of the epoxy compound to be at least the lower limit of the above range, the reaction between the epoxy compound and the polyurethane will proceed sufficiently, so that the mechanical strength of the cured layer of the liquid composition can be appropriately improved. Further, by setting the amount to be below the upper limit, the amount of unreacted epoxy compound remaining can be reduced, and the mechanical strength of the cured layer of the liquid composition can be appropriately improved.

Furthermore, the amount of the epoxy compound is preferably 0.2 times or more, more preferably 0.4 times or more, particularly preferably 0.6 times, on a weight basis, relative to the amount of the epoxy compound equivalent to the polar group of the polyurethane. It is at least 5 times, preferably at most 5.0 times, more preferably at most 4.0 times, particularly preferably at most 3.0 times. Here, the amount of the epoxy compound equivalent to the polar groups of the polyurethane refers to the theoretical amount of the epoxy compound that can react with the total amount of the polar groups of the polyurethane in just the right amount. The polar groups of the polyurethane can react with the epoxy groups of the epoxy compound. Therefore, by keeping the amount of the epoxy compound within the above range, the reaction between the polar group and the epoxy compound can proceed to an appropriate degree, and the mechanical strength of the cured layer of the liquid composition can be effectively improved. .

The liquid composition may also include a nonvolatile base. In particular, when the liquid composition contains polyurethane, it is preferable that it contains a nonvolatile base.
Examples of the non-volatile base include bases that are substantially non-volatile under the treatment conditions when the liquid composition is applied to the substrate and then dried. Here, "substantially non-volatile" generally means that the amount of non-volatile base is reduced by 80% or less. In addition, the treatment conditions for drying the liquid composition after coating it on the substrate include, for example, leaving it at 80° C. for 1 hour. Such a non-volatile base can function as a neutralizing agent to neutralize the acid structure of the polyurethane.

As the nonvolatile base, an inorganic base or an organic base may be used. Among these, organic bases with a boiling point of 100°C or higher are preferred, amine compounds with a boiling point of 100°C or higher are more preferred, and amine compounds with a boiling point of 200°C or higher are particularly preferred. Further, the organic base may be a low molecular compound or a polymer.

Examples of nonvolatile bases include inorganic bases such as sodium hydroxide and potassium hydroxide. Examples of organic bases include 2-amino-2-methyl-1-propanol (AMP), triethanolamine, triisopropanolamine (TIPA), monoethanolamine, diethanolamine, tri[(2-hydroxy)-1 -propyl]amine, 2-amino-2-methyl-1,3-propanediol (AMPD), 2-amino-2-hydroxymethyl-1,3-propane potassium hydroxide, zinc ammonium complex, copper ammonium complex, silver Ammonium complex, γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-β(aminoethyl)-γ-aminopropyltrimethoxysilane, N-β(aminoethyl)-γ-aminopropyltrimethyldimethoxysilane , N-phenyl-γ-aminopropyltrimethoxysilane, N,N-bis(trimethylsilyl)urea, 3-ureidopropyltrimethoxysilane, 3-aminopropyl-tris(2-methoxy-ethoxy-ethoxy)silane, N- Methyl-3-aminopropyltrimethoxycarboxylic acid dihydrazide, oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, adipic acid dihydrazide, sebacic acid dihydrazide, dodecanedioic acid dihydrazide, isophthalic acid dihydrazide, terephthalic acid dihydrazide, quinoline, picoline, pyridine , morpholine, piperazine, cyclohexylamine, hexamethylenediamine, N,N-dimethylformamide, ethylenediamine, diethylenetriamine, tetraethylenepentamine, pentaethylenepentamine, isopropanolamine, N,N-diethylmethanolamine, N,N-dimethylethanol Amine, aminoethylethanolamine, N-methyl-N,N-diethanolamine, 1,2-propanediamine, 1,6-hexamethylenediamine, 2-methylpiperazine, 2,5-dimethylpiperazine, isophoronediamine, 4,4 '-dicyclohexylmethanediamine, 3,3'-dimethyl-dicyclohexylmethanediamine, 1,2-cyclohexanediamine, 1,4-cyclohexanediamine, aminoethylethanolamine, aminopropylethanolamine, aminohexylethanolamine, aminoethylpropanolamine , aminopropylpropanolamine, aminohexylpropanolamine, dipropylenetriimidazole, 1-(2-aminoethyl)-2-methylimidazole, 1-(2-aminoethyl)-2-ethylimidazole, 2-aminoimidazole sulfate, 2-(2-aminoethyl)-benzimidazole, pyrazole, 5-aminopyrazole, 1-methyl-5-aminopyrazole, 1-isopropyl-5-aminopyrazole, 1-benzyl-5-aminopyrazole, 1,3- Dimethyl-5-aminopyrazole, 1-isopropyl-3-methyl-5-aminopyrazole, 1-benzyl-3-methyl-5-aminopyrazole, 1-methyl-4-chloro-5-aminopyrazole, 1-methyl- 4-cyano-5-aminopyrazole, 1-isopropyl-4-chloro-5-aminopyrazole, 3-methyl-4-chloro-5-aminopyrazole, 1-benzyl-4-chloro-5-aminopyrazole, amino resin (For example, 1,3-dimethyl-4-chloro-melamine resin, urea resin, guanamine resin, etc.). Further, these may be used alone or in combination of two or more in any ratio.

The amount of the nonvolatile base is usually 0.5 parts by weight or more, preferably 1 part by weight or more, more preferably 2 parts by weight or more, and usually 30 parts by weight or less, preferably 20 parts by weight, based on 100 parts by weight of the polyurethane. parts by weight or less, more preferably 10 parts by weight or less. By controlling the amount of the nonvolatile base to be at least the lower limit of the above range, sufficient adhesive strength can be obtained. Further, by setting the amount to be below the upper limit, it is possible to prevent color fading of the polyvinyl alcohol polarizer.

The liquid composition may contain particles. In particular, when the liquid composition contains polyurethane, it is preferable that the liquid composition contains particles. When the liquid composition contains particles, the surface roughness of the cured layer formed by the cured product of the liquid composition can be increased. This improves the slipperiness of the surface of the cured layer of the liquid composition, making it possible to prevent blocking of the optical film including the cured layer and suppress the occurrence of wrinkles when winding the optical film. becomes.

As the particles, either inorganic particles or organic particles may be used. However, it is preferable to use water-dispersible particles. Examples of materials for inorganic particles include inorganic oxides such as silica, titania, alumina, and zirconia; calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate, and calcium phosphate. etc. Furthermore, examples of materials for the organic particles include silicone resins, fluororesins, acrylic resins, and the like. Among these, silica is preferred. Silica particles have excellent ability to suppress the occurrence of wrinkles and excellent transparency, do not easily cause haze, and have no or very little coloring, so they have little effect on the optical properties of the optical film including the cured layer of the liquid composition. . Furthermore, silica has good dispersibility and dispersion stability in liquid compositions. Among silica particles, amorphous colloidal silica particles are particularly preferred.

The average particle diameter of the particles is usually 1 nm or more, preferably 5 nm or more, more preferably 10 nm or more, and usually 500 nm or less, preferably 300 nm or less, more preferably 200 nm or less. By setting the average particle diameter of the particles to be equal to or larger than the lower limit of the above range, the slipperiness of the cured layer of the liquid composition can be effectively improved. Further, by setting the amount to be equal to or less than the upper limit of the above range, the haze of the cured layer of the liquid composition can be suppressed to a low level.

The amount of particles is usually 1 part by weight or more, preferably 3 parts by weight or more, more preferably 5 parts by weight or more, and usually 50 parts by weight or less, preferably 40 parts by weight or less, more preferably, based on 100 parts by weight of the polyurethane. is 30 parts by weight or less. By controlling the amount of particles to be at least the lower limit of the above range, it is possible to suppress the generation of wrinkles when an optical film containing a cured layer of the liquid composition is wound. Further, by setting the amount to be below the upper limit, the appearance of the optical film without clouding can be maintained.

Other examples of optional components that may be included in the liquid composition include heat stabilizers, weather stabilizers, leveling agents, antioxidants, antistatic agents, slip agents, antiblocking agents, antifogging agents, lubricants, dyes, Examples include pigments, natural oils, synthetic oils, and waxes.

As for the optional components contained in the liquid composition, one type may be used alone, or two or more types may be used in combination in any ratio.

The liquid composition may contain a water-soluble solvent in addition to water. Examples of water-soluble solvents include methanol, ethanol, isopropyl alcohol, acetone, tetrahydrofuran, N-methylpyrrolidone, dimethyl sulfoxide, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, and the like. These may be used alone or in combination of two or more in any ratio.

[1.6. Applications of liquid composition]
The liquid composition can be suitably used as a coating liquid for forming a layer of the liquid composition by a coating method.
Any method can be used to apply the liquid composition, such as curtain coating, extrusion coating, roll coating, spin coating, dip coating, bar coating, spray coating, and slide coating. method, print coating method, gravure coating method, die coating method, and gap coating method.
The liquid composition can be applied over any layer. For example, the liquid composition can be coated onto a base material made of resin.

A cured layer of the liquid composition can be obtained by curing the layer of the liquid composition by heating and drying. Usually, by heating and drying the liquid composition layer, water contained in the liquid composition is removed and the liquid composition layer is cured.

The cured layer of the liquid composition may contain the components contained in the liquid composition, excluding water, as they are, or may contain a reaction product of the components contained in the liquid composition. For example, the cured layer of the liquid composition may contain a crosslinked product, polymer, condensate, etc. of the components contained in the liquid composition.

The cured layer of the liquid composition according to this embodiment has a good surface condition. Therefore, the liquid composition can be suitably used as a coating liquid for forming a layer constituting an optical film.

Furthermore, by providing a cured layer of the liquid composition between the base material and any functional layer, it may function as a primer layer that improves the adhesiveness between the base material and any functional layer. Therefore, the liquid composition can be suitably used as a coating liquid for forming a primer layer.

[2. Optical film]
The optical film according to one embodiment of the present invention is
It includes a base material and a cured layer of the liquid composition provided on the main surface of the base material.

The base material may be long or may be in the form of a single leaf. When the base material is long, an operation for providing a cured layer of the liquid composition can be performed while continuously conveying the base material, so that the optical film can be efficiently manufactured.

As the base material, a resin film containing and formed from resin can be used. As the resin constituting the base material, resin containing any polymer can be used. Among these, thermoplastic resins are preferred as the resin constituting the base material, and it is particularly preferred to use cycloolefin resins. The cycloolefin resin includes a polymer containing an alicyclic structure, such as a cycloolefin polymer or a hydride thereof. Hereinafter, a polymer containing an alicyclic structure will also be referred to as an alicyclic structure-containing polymer. Cycloolefin resins have excellent transparency, low moisture absorption, dimensional stability, light weight, etc., and are suitable for optical films.

Further, the base material may be a film with a single layer structure including only one layer, or a film with a multilayer structure including two or more layers. When the base material has a multilayer structure, it is preferable that one or more of the layers of the base material consist of a cycloolefin resin, and it is particularly preferable that at least one outermost layer of the base material consists of a cycloolefin resin. .

An alicyclic structure-containing polymer is a polymer having an alicyclic structure in the structural unit of the polymer, a polymer having an alicyclic structure in the main chain, and a polymer having an alicyclic structure in the side chain. Any polymer may be used. Further, the alicyclic structure-containing polymer may be used alone or in combination of two or more types in any ratio. Among these, from the viewpoint of mechanical strength, heat resistance, etc., polymers containing an alicyclic structure in the main chain are preferred.

Examples of the alicyclic structure include a saturated alicyclic hydrocarbon (cycloalkane) structure and an unsaturated alicyclic hydrocarbon (cycloalkene, cycloalkyne) structure. Among these, from the viewpoint of mechanical strength, heat resistance, etc., cycloalkane structures and cycloalkene structures are preferable, and among them, cycloalkane structures are particularly preferable.

The number of carbon atoms constituting the alicyclic structure is preferably 4 or more, more preferably 5 or more, and preferably 30 or less, more preferably 20 or less, particularly preferably 20 or less, per alicyclic structure. is in the range of 15 or less. This is preferable because the mechanical strength, heat resistance, and moldability of the base material are highly balanced.

The proportion of structural units having an alicyclic structure in the alicyclic structure-containing polymer may be appropriately selected depending on the purpose of use, and is preferably 55% by weight or more, more preferably 70% by weight or more, and particularly preferably is 90% by weight or more. It is preferable that the proportion of structural units having an alicyclic structure in the alicyclic structure-containing polymer is within this range from the viewpoint of transparency and heat resistance of the base material.

Examples of alicyclic structure-containing polymers include norbornene polymers, monocyclic olefin polymers, cyclic conjugated diene polymers, vinyl alicyclic hydrocarbon polymers, and hydrides thereof. can be mentioned. Among these, norbornene polymers are preferred because they have good transparency and moldability.

As the norbornene polymer, for example, a ring-opened polymer of a monomer having a norbornene structure, a ring-opened copolymer of a monomer having a norbornene structure and any monomer, or a hydrogenated product thereof; Examples include an addition polymer of a monomer having a norbornene structure, an addition copolymer of a monomer having a norbornene structure and any monomer, or a hydride thereof. Among these, hydrogenated ring-opened (co)polymers of monomers having a norbornene structure are particularly preferred from the viewpoints of transparency, moldability, heat resistance, low moisture absorption, dimensional stability, and light weight. It is. Here, the term "(co)polymer" includes both polymers and copolymers.

Examples of monomers having a norbornene structure include bicyclo[2.2.1]hept-2-ene (common name: norbornene), tricyclo[4.3.0.1 ^2,5 ]dec-3,7 -diene (common name: dicyclopentadiene), 7,8-benzotricyclo[4.3.0.1 ^2,5 ]dec-3-ene (common name: methanotetrahydrofluorene), tetracyclo[4.4. 0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene (common name: tetracyclododecene), and derivatives of these compounds (for example, those having a substituent on the ring). Here, examples of the substituent include an alkyl group, an alkylene group, and a polar group. Further, a plurality of these substituents, which are the same or different, may be bonded to the ring. Further, the monomer having a norbornene structure may be used alone or in combination of two or more in any ratio.

Examples of the type of polar group include a hetero atom or an atomic group having a hetero atom. Examples of the heteroatom include an oxygen atom, a nitrogen atom, a sulfur atom, a silicon atom, and a halogen atom. Specific examples of the polar group include carboxyl group, carbonyloxycarbonyl group, epoxy group, hydroxyl group, oxy group, ester group, silanol group, silyl group, amino group, nitrile group, sulfonic acid group, and the like.

Any monomer capable of ring-opening copolymerization with a monomer having a norbornene structure includes, for example, monocyclic olefins and derivatives thereof such as cyclohexene, cycloheptene, and cyclooctene; cyclic conjugates such as cyclohexadiene and cycloheptadiene; Dienes and derivatives thereof; and the like. Any monomer capable of ring-opening copolymerization with a monomer having a norbornene structure may be used alone or in combination of two or more in any ratio.

A ring-opening polymer of a monomer having a norbornene structure, and a ring-opening copolymer of a monomer having a norbornene structure and any monomer copolymerizable with the monomer are, for example, It can be produced by polymerization or copolymerization in the presence of a polymerization catalyst.

Examples of arbitrary monomers that can be addition-copolymerized with a monomer having a norbornene structure include α-olefins having 2 to 20 carbon atoms such as ethylene, propylene, and 1-butene, and derivatives thereof; cyclobutene, cyclopentene, Examples include cycloolefins such as cyclohexene and derivatives thereof; non-conjugated dienes such as 1,4-hexadiene, 4-methyl-1,4-hexadiene, and 5-methyl-1,4-hexadiene; and the like. Among these, α-olefin is preferred, and ethylene is more preferred. Moreover, any monomer that can be addition-copolymerized with a monomer having a norbornene structure may be used alone or in combination of two or more types in any ratio.

Addition polymers of monomers having a norbornene structure and addition copolymers of monomers having a norbornene structure and any monomer copolymerizable can be produced by, for example, adding the monomers to a known addition polymerization catalyst. It can be produced by polymerization or copolymerization in the presence of

Examples of monocyclic cyclic olefin polymers include addition polymers of cyclic olefin monomers having a single ring such as cyclohexene, cycloheptene, and cyclooctene.

Examples of cyclic conjugated diene polymers include polymers obtained by cyclizing addition polymers of conjugated diene monomers such as 1,3-butadiene, isoprene, and chloroprene; cyclic conjugated polymers such as cyclopentadiene and cyclohexadiene; Examples include 1,2- or 1,4-addition polymers of diene monomers; and hydrides thereof.

Examples of vinyl alicyclic hydrocarbon polymers include polymers of vinyl alicyclic hydrocarbon monomers such as vinylcyclohexene and vinylcyclohexane and their hydrides; vinyl aromatic hydrocarbons such as styrene and α-methylstyrene. Hydrogenated products obtained by hydrogenating the aromatic ring moiety contained in a polymer obtained by polymerizing monomers; vinyl alicyclic hydrocarbon monomers or vinyl aromatic hydrocarbon monomers and these vinyl aromatic hydrocarbon monomers Examples include hydrides of aromatic rings of copolymers such as random copolymers or block copolymers with any monomer that can be copolymerized. Examples of the block copolymers include diblock copolymers, triblock copolymers, or higher multiblock copolymers, and tilted block copolymers.

The weight average molecular weight (Mw) of the polymer contained in the resin constituting the base material is usually 10,000 or more, preferably 15,000 or more, more preferably 20,000 or more, and usually 100,000 or less, preferably is 80,000 or less, more preferably 50,000 or less. Here, the above-mentioned weight average molecular weight is a weight average molecular weight in terms of polyisoprene or polystyrene measured by GPC using cyclohexane as a solvent. However, if the sample does not dissolve in cyclohexane, toluene may be used as the GPC solvent. When the weight average molecular weight is within this range, the mechanical strength and moldability of the optical film are highly balanced, which is preferable.

The molecular weight distribution (weight average molecular weight (Mw)/number average molecular weight (Mn)) of the polymer contained in the resin constituting the base material is usually 1.2 or more, preferably 1.5 or more, and more preferably 1.8. It is usually 3.5 or less, preferably 3.0 or less, and more preferably 2.7 or less. By controlling the molecular weight distribution to be equal to or higher than the lower limit of the above range, productivity of the polymer can be increased and costs can be suppressed. Further, by setting the amount to be below the upper limit value, it is possible to reduce the low molecular weight components, so that the relaxation time can be lengthened. Therefore, relaxation during high temperature exposure can be suppressed, and the stability of the base material can be improved.

The polymer contained in the resin constituting the group preferably has an absolute value of photoelastic coefficient C of 10×10 ⁻¹² Pa ⁻¹ or less, more preferably 7×10 ⁻¹² Pa ⁻¹ or less. , 4×10 ⁻¹² Pa ⁻¹ or less is particularly preferable. The photoelastic coefficient C is a value expressed by "C=Δn/σ", where birefringence is Δn and stress is σ. By keeping the photoelastic coefficient of the polymer within the above range, variations in the in-plane retardation Re of the base material can be reduced.

The saturated water absorption rate of the polymer contained in the resin constituting the base material is preferably 0.03% by weight or less, more preferably 0.02% by weight or less, particularly preferably 0.01% by weight or less. When the saturated water absorption rate is within the above range, changes over time in the in-plane retardation Re and the thickness direction retardation Rth of the base material can be reduced.

The saturated water absorption rate is a value expressed as a percentage of the mass increased by immersing a test piece in water at a constant temperature for a certain period of time with respect to the mass of the test piece before immersion. Usually, it is measured by immersing it in water at 23° C. for 24 hours. The saturated water absorption rate in the polymer can be adjusted within the above range by, for example, reducing the amount of polar groups in the polymer. From the viewpoint of lowering the saturated water absorption rate, it is preferable that the above-mentioned polymer does not have a polar group.

The resin constituting the base material may contain any component other than the polymer, as long as it does not significantly impair the effects of the present invention. Examples of optional components include colorants such as pigments and dyes; plasticizers; optical brighteners; dispersants; heat stabilizers; light stabilizers; ultraviolet absorbers; antistatic agents; antioxidants; lubricants. ; Examples include additives such as surfactants. One type of these components may be used alone, or two or more types may be used in combination in any ratio.

However, the amount of polymer contained in the resin constituting the base material is generally 50% to 100%, for example 70% to 100%, for example 80% to 100%, for example 90% to 100%. It is preferable to adjust the amount of any component thereof.

However, it is preferable that the cycloolefin resin contains substantially no particles. Here, "substantially free of particles" means that even if particles are included in the resin, the haze of the base film increases by 0.05% or less from the state of not containing any particles. means acceptable. Alicyclic structure-containing polymers tend to lack compatibility with many organic and inorganic particles. Therefore, when a cycloolefin resin containing particles in an amount exceeding the above range is stretched, voids are likely to occur, and as a result, a significant increase in haze may occur.

As mentioned above, the base material may be a film layer with a single layer structure including only one layer, or may be a film layer with a multilayer structure including two or more layers. By forming the base material into a film layer having a multilayer structure, optical films having various properties can be manufactured.

When the base material has two or more layers, it may have two or more of one type of film layer, or it may have two or more different types of film layers. Further, the base material may be provided with a layer made of a resin other than the above-mentioned cycloolefin resin. Examples of the layer made of other than cycloolefin resin include a film layer having functions such as scratch prevention, antireflection, antistatic, antiglare, and antifouling.

The base material preferably has a total light transmittance of 80% or more, more preferably 90% or more, based on a thickness of 1 mm. The total light transmittance can be measured using a spectrophotometer (UV-visible near-infrared spectrophotometer "V-570" manufactured by JASCO Corporation) in accordance with JIS K0115.
Further, the haze of the base material at a thickness of 1 mm is preferably 0.3% or less, more preferably 0.2% or less. Here, haze is an average value obtained from measurements at five locations using "Turbidity Meter NDH-300A" manufactured by Nippon Denshoku Industries Co., Ltd. in accordance with JIS K7361-1997.

The average thickness of the base material is preferably 5 μm or more, more preferably 20 μm or more, and preferably 500 μm or less, more preferably 300 μm or less. It is preferable that the thickness variation width of the base material is within ±3% of the average thickness in both the longitudinal direction and the width direction. By controlling the thickness variation within the above range, variations in optical properties such as retardation of the base material can be reduced.

The base material may be an unstretched film that has not been subjected to a stretching process, or may be a stretched film that has been subjected to a stretching process. In addition, when the base material has two or more layers, a stretched film may be obtained by bonding film layers that have been subjected to stretching treatment in advance, and a stretched film with a multilayer structure obtained by coextrusion etc. A stretched film may be obtained by performing a stretching process.

The base material may be subjected to surface treatment such as energy ray irradiation treatment such as corona discharge treatment, plasma treatment, electron beam irradiation treatment, and ultraviolet irradiation treatment; chemical treatment; Among these, corona discharge treatment and plasma treatment are preferred from the viewpoint of treatment efficiency, and corona discharge treatment is more preferred.

The cured layer of the liquid composition is a layer obtained by curing a layer of the liquid composition.

As mentioned above, the cured layer of the liquid composition may contain the components contained in the liquid composition, excluding water, as they are, or may contain reaction products of the components contained in the liquid composition. You can stay there.

The cured layer of the liquid composition may be provided on one of the two main surfaces of the base material, or may be provided on both main surfaces.

The cured layer of the liquid composition is preferably provided directly on the main surface of the base material.

The thickness of the cured layer of the liquid composition is not particularly limited, but may be, for example, 0.005 μm to 5 μm.

The optical film may include any layer in addition to the substrate and the cured layer of the liquid composition. Examples of the arbitrary layer include an antireflection layer, a hard coat layer, an antistatic layer, an antiglare layer, an antifouling layer, and a separator film. These arbitrary layers may be manufactured separately from the multilayer film comprising the substrate and the cured layer of the liquid composition, and bonded to the multilayer film. Further, an arbitrary layer may be further formed on the main surface of the multilayer film by a coating method.

The optical film preferably has a total light transmittance of 80% or more, more preferably 90% or more, from the viewpoint of stably exhibiting its function as an optical member.

The haze of the optical film is preferably 5% or less, more preferably 3% or less, particularly preferably 2% or less. By setting the haze to a low value, when the optical film is incorporated into a display device, the clarity of the displayed image on the display device can be improved.

The optical film may be a retardation film having retardation in the plane or in the thickness direction. A specific range of retardation can be set depending on the use of the optical film of this embodiment. Specifically, the in-plane retardation Re is usually selected from the range of 10 nm to 500 nm, and the thickness direction retardation Rth is appropriately selected from the range of -500 nm to 500 nm.

[3. Optical film manufacturing method]
The optical film described above may be manufactured by any method.
Preferably, a step (1) of preparing a base material, a step (2) of coating a liquid composition on the main surface of the base material to form a layer of the liquid composition, and a step (2) of forming a layer of the liquid composition on the main surface of the base material. An optical film can be manufactured by a method including, in this order, a step (3) of drying the layer to form a cured layer of the liquid composition.

There are no restrictions on the manufacturing method of the base material. The base material is obtained by molding a resin for forming the base material using a known film molding method. Examples of film molding methods include cast molding, extrusion molding, and inflation molding. Among these, a melt extrusion method that does not use a solvent is preferable from the viewpoints of being able to efficiently reduce the amount of residual volatile components and being excellent in terms of global environment, work environment, and production efficiency. Examples of the melt extrusion method include an inflation method using a die, and among them, a method using a T-die is preferable because it is excellent in productivity and thickness accuracy.

When the base material includes two or more layers, there are no restrictions on the method of manufacturing the base material. For example, the base material may be manufactured by bonding separately manufactured film layers together using an adhesive as needed.
When manufacturing a base material with two or more layers without using an adhesive, for example, coextrusion molding methods such as coextrusion T-die method, coextrusion inflation method, and coextrusion lamination method; films such as dry lamination. A lamination molding method or the like can be used.

Furthermore, a base material having two or more layers may be manufactured using, for example, a coating molding method in which the surface of one film layer is coated with a solution containing a resin constituting another film layer.

Among these, the coextrusion molding method is preferred from the viewpoint of production efficiency and from the viewpoint of not leaving volatile components such as solvents in the base material. Among the coextrusion molding methods, the coextrusion T-die method is particularly preferred. Furthermore, the coextrusion T-die method includes a feed block method and a multi-manifold method, but the multi-manifold method is more preferable from the viewpoint of reducing variations in the thickness of the film layer.

Any coating method can be used to coat the liquid composition on the main surface of the base material.
Examples of methods for drying the layer of the liquid composition include natural drying, heat drying, vacuum drying, and combinations thereof.
The liquid composition of this embodiment generates less stain when dried. From the viewpoint of effectively exhibiting the advantages of the liquid composition of this embodiment, it is preferable to dry the layer of the liquid composition by a method including heat drying.

When drying the layer of the liquid composition by heating, a heating drying device such as an oven can be used. The temperature inside the heating drying device is not particularly limited, but may be, for example, Tg - 30°C or higher, for example, Tg + 30°C or lower. Here, Tg represents the glass transition temperature of the resin forming the base material.

The method for producing an optical film may include any steps in addition to steps (1) to (3) above. Examples of optional steps include stretching the substrate. When the method for producing an optical film includes a step of stretching the base material, the base material may be stretched before step (2), or the base material may be stretched after step (2), The base material may be stretched simultaneously with step (3), or after step (3).
When stretching the base material after step (2), a layer provided on the main surface of the base material (for example, a cured layer of a liquid composition) is usually also stretched at the same time as the base material.

The stretching method for stretching the base material is not particularly limited, and any stretching method may be used. Examples of stretching methods include uniaxial stretching methods such as a method of uniaxially stretching the film in the longitudinal direction (longitudinal uniaxial stretching method), a method of uniaxially stretching the film in the width direction (horizontal uniaxial stretching method); Biaxial stretching methods such as a simultaneous biaxial stretching method in which the film is stretched in the width direction at the same time as stretching, and a sequential biaxial stretching method in which the film is stretched in one of the longitudinal and width directions and then in the other direction; A method of stretching in the direction (oblique stretching method) can be mentioned.

The stretching temperature is preferably (Tg - 30°C) or higher, more preferably (Tg - 10°C) or higher, preferably (Tg + 50°C) or lower, with the glass transition temperature of the resin constituting the stretched film being Tg. , more preferably (Tg+30°C) or less. The stretching ratio can be appropriately selected depending on the optical properties of the base material used. The specific stretching ratio is usually 1.05 times or more, preferably 1.1 times or more, and usually 10.0 times or less, preferably 2.0 times or less.

[4. Applications of optical film]
The optical film of this embodiment can be suitably used as, for example, a protective film for optical elements (particularly a polarizer protective film), a retardation film, and an optical compensation film. In particular, when the cured layer included in the optical film is formed as a layer having adhesive properties, the optical film can be bonded to any member with good adhesive properties.

Hereinafter, the present invention will be specifically described with reference to Examples. However, the present invention is not limited to the embodiments shown below, and may be implemented with arbitrary changes within the scope of the claims of the present invention and equivalents thereof.

In the following description, "%" and "part" expressing amounts are based on weight, unless otherwise specified. Further, the operations described below were performed at room temperature (20° C.±15° C.) and normal pressure (1 atm) unless otherwise specified.

[Evaluation method]
(Measurement of number average molecular weight, weight ratio of component (L))
The surfactant compositions used in Examples and Comparative Examples were measured by GPC under the following conditions. During the measurement, a calibration curve was created using polystyrene as a standard substance.
Injection sample: 0.1% by weight tetrahydrofuran (THF) solution Column temperature: 40°C
Developing solvent: THF
Detector: Differential refractometer (RI)
Based on the GPC measurement results, the weight proportion of the component (L) with a number average molecular weight of 100 or more and 500 or less, and the number average molecular weight of the surfactant component with a number average molecular weight of more than 500 and its weight proportion were determined.
Specifically, in the chromatograms of the surfactant compositions used in Examples and Comparative Examples, the area of the peak of the component whose number average molecular weight is 100 or more and 500 or less, with the sum of the areas of all peaks taken as 100%. (If there are multiple peaks, the sum of their areas) R _L (%) is calculated, and the area ratio R _N ( %) was calculated. Based on these proportions, the weight proportion of the component (L) with a number average molecular weight of 100 or more and 500 or less in the surfactant composition is defined as R _L weight %, and the number average molecular weight is more than 500. The weight proportion of the surfactant component was defined as R _N weight %.

(Dispersibility of silica particles, surface condition of cured layer of liquid composition)
The multilayer films obtained in Examples and Comparative Examples were irradiated with high-intensity light (Polarion clean room light) and the state of the film surface (surface shape) was visually observed.

The dispersibility of silica particles was evaluated according to the following criteria.
Good: The entire film is uniformly and slightly cloudy, and the silica particles are uniformly dispersed.
Fair: The film has some dark cloudy areas (unevenness), but is acceptable for practical purposes.
Defective: There are many dark cloudy areas (unevenness) on the film.
The higher the evaluation, the higher the dispersibility of the silica particles in the liquid composition.

The surface condition of the cured layer of the liquid composition was evaluated according to the following criteria.
Good: The entire film is uniformly thin and cloudy, and no bleeding pattern of the surfactant is observed.
Fair: Bleeding patterns of surfactant are observed on the film, but there are no cloudy areas (dropouts).
Defective: There is a part (missing) in the film that is not cloudy at all.
If there are parts of the film that are not cloudy at all, this means that air bubbles were generated when the liquid composition was applied.

(Residual rate of surfactant in cured layer of liquid composition)
Calculate the amount of surfactant X0 used to produce 1 g of multilayer film including the base material (Zeonor film) from the thickness of the multilayer film obtained in the examples and comparative examples and the amount of surfactant charged. did.
Further, the amount X1 of surfactant remaining in 1 g of the multilayer film was calculated using the following analysis results. The residual ratio R of the surfactant in the cured layer of the liquid composition was calculated using the following formula.
R=X1/X0*100(%)
Further, the residual rate R was classified according to the following criteria.
Good: 90%≦R
Possible: 70%≦R<90%
Defective: R<70%

・Analysis Weigh 1 g of multilayer film into a 500mL container, add 100mL of cyclohexane, leave it overnight, and then stir with a magnetic stirrer to dissolve most of the multilayer film and remove some white insoluble matter. It was made into a solution. 50 mL of THF was added to the solution containing the insoluble matter, and then methanol was added until the total amount was about 400 mL to form a precipitate.
The precipitate was removed by filtration through a pleated filter paper, and the solvent was distilled off from the filtrate under reduced pressure to obtain a methanol-soluble liquid. The operation of removing the solvent under reduced pressure was carried out in several batches using a 100 mL eggplant flask and an evaporator. This liquid was transferred to a 10 mL volumetric flask, and the solvent: methanol was added up to the marked line to make the volume constant.
The fixed volume of the liquid was filtered through a 0.2 um filter, transferred to a vial, and the concentration of the surfactant was measured by HPLC measurement under the following conditions. The surfactant concentration was determined based on a calibration curve prepared in advance by analyzing surfactant solutions having different concentrations.
From the concentration of the surfactant obtained, the amount X1 of the surfactant remaining in 1 g of the multilayer film was calculated.

・HPLC conditions Column used: ZORBAX Eclipse XDB-C8
Column temperature: 40℃
Developing solvent: acetonitrile/gradient elution from ammonium formate to acetonitrile flow rate: 0.5 mL/min
Injection volume: 2μL
Detector: Mass spectrometer

A larger residual ratio R means that stains are less likely to occur when heating and drying a layer of the liquid composition. Therefore, the larger the residual rate R is, the less resinous dirt adheres to the inside of the heating dryer.

[Surfactant composition used in Examples and Comparative Examples]
The compositions of surfactant compositions A to G used in Examples and Comparative Examples are shown in Table 1. In Table 1, compositions A to G mean surfactant compositions A to G, respectively. Surfactant compositions A to G were obtained commercially. In Table 1, the numerical values of surfactant component Mn in Composition F and Composition G are values for components having a number average molecular weight of 500 or less.

[Example 1]
(1-1) Preparation of base material Pellets of cycloolefin resin (ZEONOR1420 manufactured by Nippon Zeon Co., Ltd.) were dried at 100° C. for 5 hours. The pellets are supplied to an extruder, melted in the extruder, passed through a polymer pipe and a polymer filter, extruded into a film from a T-die onto a casting drum, cooled, and made into a long unstretched film (thickness 80 μm, width 1600 mm) was obtained. From there, a sample was cut into A4 size (approximately 210 mm x approximately 297 mm).

One side of the cut unstretched film was subjected to electrical discharge treatment using a corona treatment device, and was used as a base material for forming a cured layer of the liquid composition.

(1-2) Formation of layer of liquid composition Superflex 870 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., ether polyurethane, Tg 78°C, solid content 30%) was used as an aqueous dispersion of polyurethane (polyurethane emulsion). An amount of the water dispersion containing 100 parts of polyurethane was taken out. To this aqueous dispersion, 20 parts of glycerol polyglycidyl ether (“Denacol EX-512” manufactured by Nagase ChemteX), which is an epoxy compound; and 8 parts of silica fine particles with an average particle diameter of 80 nm (“Snowtex ZL” manufactured by Nissan Chemical Co., Ltd.) 2.5 parts of an aqueous dispersion of silica particles (Nissan Chemical Co., Ltd. "Snowtex MP2040"; average particle diameter 200 nm); number average molecular weight of 4,660 as a nonionic surfactant; A solid containing a polyurethane resin in an uncured state is prepared by blending surfactant composition A containing a surfactant and a low molecular weight component (L) having a molecular weight of 500 or less at 11% of the total; and water. A liquid composition having a concentration of 4% was obtained. Here, the amount of the nonionic surfactant composition added is 1.25 wt% based on the solid content contained in the liquid composition, and 500 ppm by weight (0.05 wt%) based on the liquid composition. did.

The above liquid composition was coated with a bar coater on the discharge-treated surface of the unstretched film as a cut out base material so that the dry thickness was 0.08 μm.

(1-3) Formation of cured layer of liquid composition Thereafter, the layer of the liquid composition was dried by heating to form a cured layer of the liquid composition to serve as a primer layer on the unstretched film. As a result, a multilayer film as an optical film including a base material and a cured layer of the liquid composition was obtained. The obtained multilayer film was evaluated by the method described above. The results are shown in Table 2.

[Examples 2 to 9, Comparative Examples 1 to 2]
Surfactant compositions shown in Tables 2 to 4 were used instead of surfactant composition A.
The amount of the surfactant composition added was changed to the amount shown in Tables 2 to 4.
Except for the above matters, the same operations as in Example 1 were carried out to obtain a multilayer film as an optical film, and evaluation was performed in the same manner as in Example 1. The results are shown in Tables 2 to 4.

[result]
The evaluation results are shown in Tables 2 to 4.
Abbreviations in Tables 2 to 4 have the following meanings.
"Additional amount of surfactant composition": Addition amount of surfactant composition based on 100% by weight of the liquid composition.
"Surfactant (net) addition amount": Addition amount of the surfactant component having a number average molecular weight of more than 500 in the surfactant composition, based on 100% by weight of the liquid composition.
"Surfactant (N)/component (L)": The surfactant of the nonionic surfactant (N) with a number average molecular weight of more than 500 in the surfactant composition, which is blended into the liquid composition. weight ratio to component (L) in the agent composition.
Note in Table 4 *1: Anionic surfactant is included, nonionic surfactant (N) is not included.
Note *2 in Table 4: Nonionic surfactant (N) with a number average molecular weight of more than 500 is not included.

As shown in the above results, it contains a nonionic surfactant (N) with a number average molecular weight exceeding 500, and the weight ratio of the nonionic surfactant (N) to the component (L) is 70/30 or more. (That is, the liquid composition according to the example contains 70 parts by weight or more and 100 parts by weight of nonionic surfactant (N) and 0 part by weight or more and 30 parts by weight or less of component (L).) Surfactant residual rate evaluation is good or fair, and surface condition evaluation is good or fair. Therefore, the liquid compositions according to Examples show that volatile stains are less likely to occur during drying, and the surface condition of the cured layer of the liquid composition is good.

On the other hand, in the liquid composition of Comparative Example 1 using an anionic surfactant, the surface condition of the cured layer of the liquid composition was poor. In addition, the liquid composition of Comparative Example 2 using a nonionic surfactant with a number average molecular weight of 500 or less had a poor surfactant residual rate evaluation, and the amount of volatile stains generated during drying was poor. Indicates that there are many

Claims

70 parts by weight or more and 100 parts by weight or less of a nonionic surfactant having a number average molecular weight of more than 500;
0 parts by weight or more and 30 parts by weight or less of a component having a number average molecular weight of 100 or more and 500 or less;
A liquid composition containing water.
The liquid composition according to claim 1, wherein the nonionic surfactant has a number average molecular weight of 550 or more.
The liquid composition according to claim 1, containing the nonionic surfactant at 0.02% by weight or more and 0.10% by weight or less.
The liquid composition according to claim 1, further comprising polyurethane and silica particles.
An optical film comprising a base material and a cured layer of the liquid composition according to any one of claims 1 to 4 provided on the main surface of the base material.
The optical film according to claim 5, wherein the base material is made of a cycloolefin resin.