JP2020104513A - Laminate film wound body, laminate having hard coat film, and polarizing plate - Google Patents

Abstract

To provide a laminate film wound body including a hard coat film and a protective film, capable of preventing stripes from being generated on a surface of a laminate having a hard coat film disposed on a polarizing plate, etc.SOLUTION: A laminate film wound body is obtained by winding up, into a rolled state, a laminate film including: a hard coat film of 30 μm thick or less, having a substrate layer and a hard coat layer; and a protective film. The hard coat film has a tensile elastic modulus of 3000 MPa or less in a wound direction thereof at temperature 23°C and relative humidity 55%. The hard coat film removed from the laminate film has a standard deviation of 0.25 μm or less with regard to a film thickness distribution in a wound axial direction. The hard coat film removed from the laminate film has pencil hardness of 5B or higher and lower than H.SELECTED DRAWING: None

Description

The present invention relates to a laminated film roll, a laminate with a hard coat film, and a polarizing plate.

Various optical films are used in display devices such as liquid crystal display devices and organic electroluminescence (EL) display devices. A polarizing plate is mentioned as one of such optical films. The polarizing plate is provided with a protective layer for protecting the polarizing layer on one side or both sides of the polarizing layer. The protective layer used for the polarizing plate may be provided with a hard coat layer in order to improve its surface hardness (for example, Patent Documents 1 to 4).

JP, 2005-103878, A JP, 2009-292871, A JP, 2013-136774, A JP, 2017-82240, A

The protective layer provided with the hard coat layer (hereinafter, may be referred to as “HC layer-attached film”) may have a hard coat layer (hereinafter, referred to as “the film with the HC layer”) at the time of production or market distribution (before being attached to the polarizing layer). In some cases, the HC layer side of the film with the HC layer is a laminated film in which a protective film is covered in order to prevent the "HC layer" from being damaged. Further, the film with the HC layer may be used by being stuck to the surface of the polarizing layer to obtain a polarizing plate, but the sticking of the polarizing layer and the film with the HC layer may be carried out by using each long product. It is usually done continuously. Therefore, the above-mentioned laminated film is also obtained as a long product, and the long laminated film is wound into a roll to form a laminated film roll, which is marketed or stored.

When the polarizing layer and the film with the HC layer are attached, the protective film is peeled off from the laminated film obtained by unwinding the laminated film roll, and then the film with the HC layer is attached to the polarizing layer. A polarizing plate having a film with an HC layer is obtained. The present inventors have found that streaks may be visually recognized on the surface of the polarizing plate thus obtained on the film side with the HC layer.

The present invention provides a laminated film roll capable of suppressing the occurrence of streaks on the surface of a laminated body with a hard coat film such as a polarizing plate provided with a hard coat film, a laminated body with a hard coat film, and a polarizing plate. For the purpose of provision.

The present invention provides the following laminated film roll and polarizing plate.
[1] A laminated film winding body obtained by winding a laminated film into a roll,
The laminated film has a hard coat film having a base layer and a hard coat layer, and a protective film,
The thickness of the hard coat film is 30 μm or less,
The tensile elastic modulus at a temperature of 23° C. and a relative humidity of 55% in the winding direction of the hard coat film is 3000 MPa or less,
The standard deviation of the film thickness distribution in the winding axis direction of the hard coat film peeled from the laminated film is 0.25 μm or less,
The laminated film wound body, wherein the pencil hardness of the hard coat film separated from the laminated film is 5B or more and less than H.

[2] The laminated film wound body according to [1], wherein the protective film is provided on the hard coat layer side of the hard coat film.

[3] The laminated film wound body according to [1] or [2], wherein the protective film is provided on the base layer side of the hard coat film.

[4] The laminated film winding according to any one of [1] to [3], wherein the standard deviation of the film thickness distribution in the winding axis direction of the protective film peeled from the laminated film is 0.68 μm or less. Circulation.

[5] The laminated film wound body according to any one of [1] to [4], wherein the protective film has self-adhesiveness.

[6] The laminated film wound body according to any one of [1] to [5], wherein the standard deviation of the film thickness distribution in the winding axis direction of the laminated film is 0.68 μm or less.

[7] A laminate with a hard coat film, comprising a hard coat film peeled from the laminate film according to any one of [1] to [6] and an adherend.

[8] The laminated body with a hard coat film according to [7], wherein the hard coat film separated from the laminated film and the adherend are laminated via an adhesive layer.

[9] A polarizing plate having a polarizing layer and a hard coat film separated from the laminated film according to any one of [1] to [6].

According to the present invention, it is possible to provide a laminate with a hard coat film such as a polarizing plate in which the generation of stripes is suppressed.

(Rolled film roll)
The laminated film winding body of the present embodiment is a laminated film winding body in which a laminated film is wound in a roll shape. The laminated film has a hard coat film (hereinafter sometimes referred to as “HC film”) and a protective film. The HC film has a base material layer and a hard coat layer (hereinafter sometimes referred to as “HC layer”). The HC film can be used as, for example, a protective layer for protecting the surface of the polarizing layer, and can be laminated on the polarizing layer to form a polarizing plate, as described later. The protective film is used as a protective layer for protecting the surface of the HC layer of the HC film, or to prevent blocking between the HC layer and the base material layer when the HC film is used as a wound body. Can be used for. When a protective film is used to protect the surface of the HC layer, the protective film can be provided on the HC layer side of the HC film. When used to prevent blocking between the HC layer and the base material layer, the protective film can be provided on the base material layer side of the HC film. The protective film is usually provided on one side of the HC film, but it may be provided on both sides of the HC film.

In the laminated film roll, the thickness of the HC film is 30 μm or less. The thickness of the HC film may be 28 μm or less, 25 μm or less, 23 μm or less, and usually 8 μm or more, 10 μm or more, 12 μm or more. May be. The thickness of the base material layer included in the HC film may be 29 μm or less, 25 μm or less, 20 μm or less, 5 μm or more, and 10 μm or more. May be. The thickness of the HC layer included in the HC film may be 15 μm or less, 10 μm or less, 5 μm or less, 0.1 μm or more, and 0.5 μm or more. It may be present or may be 1 μm or more. By setting the standard deviation of the film thickness distribution of the HC film having a thickness in the above range to be in the range described below, it is possible to suppress streaks occurring on the HC film side of the laminate with the HC film. The thickness of the HC film can be measured by the method for measuring the thickness of the HC film described in Examples below. Further, the thicknesses of the base material layer and the HC layer can also be measured according to the method for measuring the thickness of the HC film described in Examples below.

In the laminated film roll, the tensile elastic modulus at a temperature of 23° C. and a relative humidity of 55% in the winding direction (flow direction) of the HC film is 3000 MPa or less. The tensile modulus of elasticity of the HC film may be 2800 MPa or less, 2500 MPa or less, ordinarily 800 MPa or more, 1000 MPa or more, and 1200 MPa or more. By setting the standard deviation of the film thickness distribution of the HC film having the tensile elastic modulus in the above range to be in the range described below, it is possible to suppress streaks that occur on the HC film side of the laminate with the HC film. The tensile elastic modulus at a temperature of 23° C. and a relative humidity of 55% in the winding direction of the HC film can be measured by the method described in Examples described later.

In the laminated film roll, the standard deviation of the film thickness distribution in the winding axis direction (width direction) of the HC film separated from the laminated film is 0.25 μm or less. The standard deviation of the above film thickness distribution of the HC film may be 0.23 μm or less, may be 0.20 μm or less, and is usually 0.05 μm or more and may be 0.1 μm or more. Good. The standard deviation of the film thickness distribution of the HC film in the winding axis direction (width direction) can be measured by the method described in Examples below.

The HC film obtained by unwinding the laminated film roll can be laminated on an adherend such as a polarizing layer to form a laminate with an HC film such as a polarizing plate. In a laminate with an HC film in which an HC film obtained from a laminate film obtained by unwinding a laminate film winding body is laminated on an adherend, a streak may be visually recognized on the HC film side. The present inventors have found that when the thickness of the HC film is 30 μm or less and the tensile elastic modulus is 3000 MPa or less, it is likely to occur. Since the streak generated on the HC film cannot be eliminated by a post-treatment such as heating because it has an HC layer, it is desirable to suppress the streak generation in the HC film obtained from the laminated film roll. Be done. As a result of a study for suppressing streaks visually recognized in the HC film, a standard deviation of the film thickness distribution in the winding axis direction of the HC film obtained from the laminated film obtained by unwinding the laminated film winding body is 0. It was found that streaks visually recognized in the laminate with the HC film can be suppressed by using a film having a thickness of 25 μm or less.

The reason why the standard deviation of the film thickness distribution in the winding axis direction of the HC film is 0.25 μm or less suppresses the visual recognition of streaks on the surface of the laminate with the HC film is not clear, but is as follows. Guessed. The HC film obtained by unwinding the laminated film roll has a state in which the HC film is in a state before the protective film is provided (before the laminated film is formed) (standard deviation of film thickness distribution, etc.). When laminated (standard deviation of film thickness distribution of protective film, tension when laminating HC film and protective film, etc.), winding state in laminated film wound body (tension at winding, It is considered to have a shape that reflects the influence of various factors such as the degree of tightness of winding.

For example, when the standard deviation of the film thickness distribution of each film (HC film, protective film) before being made into a laminated film is large, the HC film obtained by unwinding the laminated film roll has a standard deviation of the film thickness distribution. Is considered to be getting larger. In addition, when the HC film and the protective film are attached to each other or when the laminated film is wound, tension is usually applied to the film, but if the film thickness is different, the stretching is also different. It is considered that the standard deviation of the film thickness distribution increases when tension is applied to the film having a large standard deviation of. Further, the laminated film winding body is wound by winding air therein, and is wound up after the winding air is gradually released. It is considered that the laminated film or each film forming the laminated film is deformed by the winding tightening. In particular, when the standard deviation of the film thickness distribution of the laminated film or each film forming the laminated film is large, the amount of air entrained during winding tends to vary, and the degree of air escape tends to be uneven, so that the laminated film or It is considered that the amount of deformation of each film forming the laminated film is likely to be large.

As described above, in the HC film obtained by unwinding the laminated film winding body, the entire film surface is not flat along the horizontal plane but is partially deformed due to the influence of various factors described above. It is believed that In an HC film having a large standard deviation of the film thickness distribution in the winding axis direction, the deformation amount of the deformed portion becomes large. Therefore, an HC film having such a large standard deviation of the film thickness distribution in the winding axis direction is used. It is considered that streaks are easily visible on the surface of the laminate with the HC film obtained by laminating it on the adherend.

When the thickness of the HC film is small, or when the tensile elastic modulus is small, it is easily affected by the various factors described above. Therefore, the amount of partial deformation of the HC film obtained from the laminated film roll is Easy to grow. Therefore, as the HC film having a thickness of 30 μm or less and the tensile modulus of 3000 MPa or less, a film having a small standard deviation of the film thickness distribution in the winding axis direction is generated in the laminate with the HC film. Streaks can be suppressed appropriately.

The standard deviation of the film thickness distribution in the winding axis direction of the HC film peeled from the laminated film of the laminated film roll is 0.25 μm or less, for example, an HC film or a protective film before being made into a laminated film. As the standard deviation of the film thickness distribution of the HC film peeled from the laminated film of the laminated film roll as an HC film before being formed into a laminated film. Used, or as the protective film before being made into a laminated film, one having a standard deviation of the film thickness distribution in the winding axis direction of the protective film peeled from the laminated film of the laminated film roll is used) , A substrate layer having a small standard deviation of the film thickness distribution is used as the substrate layer before being made into an HC film, and the viscosity of the photocurable resin composition applied to the substrate layer to form the HC layer is adjusted. Adjusting the curing conditions (illuminance and light amount of light to be irradiated) when curing the photocurable resin composition applied on the base material layer, and laminating an HC film and a protective film to obtain a laminated film It can be obtained by adjusting the lamination conditions at that time (tension applied to the HC film or the protective film during lamination), adjusting the tension when winding the laminated film, and the like.

In the laminated film roll, the pencil hardness of the HC film peeled off from the laminated film may be less than H (softer than H), for example, F, HB, B, 2B, 3B, 4B. It is good and is usually 5B or more. The pencil hardness of the HC film can be measured according to the pencil hardness test defined in JIS K5600-5-4:1999. When the pencil hardness of the HC film is low, it is likely to be affected by the various factors described above, and thus the amount of partial deformation of the HC film described above tends to be large. Therefore, by using an HC film having a pencil hardness of less than H with a small standard deviation of the film thickness distribution in the winding axis direction, it is possible to suitably suppress the streaks that occur in the laminate with the HC film. The pencil hardness of the HC film can be adjusted by adjusting the material and thickness of the HC layer and the material and thickness of the base material layer.

In the laminated film roll, the standard deviation of the film thickness distribution in the winding axis direction of the protective film peeled from the laminated film is preferably 0.68 μm or less, and may be 0.65 μm or less, 0 It may be less than 60 μm. The standard deviation of the film thickness distribution of the protective film in the winding axis direction (width direction) can be measured by the method described in Examples described later. When the standard deviation of the film thickness distribution of the protective film in the winding axis direction is large, it is estimated that the standard deviation of the film thickness distribution of the protective film before being bonded to the HC film is also large. When such a protective film is laminated with an HC film to form a laminated film and the laminated film is wound to form a laminated film roll, it is considered that the above deformation is likely to occur in the HC film with a larger deformation amount. .. Therefore, the standard deviation of the film thickness distribution in the winding axis direction of the protective film separated from the laminated film is preferably small. The standard deviation of the film thickness distribution in the winding axis direction of the protective film peeled from the laminated film of the laminated film roll adjusts the standard deviation of the film thickness distribution as the protective film before being made into the laminated film (for example, As the protective film before being made into a laminated film, one having a standard deviation of the film thickness distribution in the winding axis direction of the protective film peeled from the laminated film of the laminated film roll is used), an HC film and a protective film. Can be adjusted by adjusting the laminating conditions (the tension applied to the HC film or the protective film at the time of laminating) when the and are laminated to obtain a laminated film, and adjusting the tension when winding the laminated film. it can.

When adjusting the tension (tension before lamination) applied to the protective film when the HC film and the protective film are laminated to obtain a laminated film, the tension is preferably 0.03 N/mm or more, It may be 0.04 N/mm or more, preferably 0.35 N/mm or less, more preferably 0.2 N/mm or less, and further preferably 0.1 N/mm or less. It is particularly preferably 0.08 N/mm or less, and may be 0.06 N/mm or less. When the tension is low, the protective film is likely to meander and the transportability is likely to be deteriorated. When the tension is increased, the curl generated in the laminated film after laminating the protective film is likely to be large, and thus the protective film is likely to be deformed, and the HC film peeled from the laminated film of the laminated film winding body is wound. The standard deviation of the film thickness distribution in the direction of the axis tends to be large.

The tension (winding tension) when the laminated film is wound can be, for example, 0.05 N/mm or more and 0.35 N/mm or less. When the winding tension is small, winding deviation easily occurs in the laminated film winding body. When the winding tension increases, a bump (winding bump), which is observed as a protrusion along the circumferential direction, tends to occur in the wound body of the laminated film, and the HC film tends to deform due to winding.

Further, the protective film forming the laminated film of the laminated film roll preferably has self-adhesiveness. In the present specification, the self-adhesive property refers to the property that the self-adhesive property can be applied by itself without the provision of a means for adhering the pressure-sensitive adhesive layer or the like, and can maintain the adhered state. The protective film having self-adhesiveness can reduce the total thickness as compared with the protective film having an adhesive layer. As a result, the HC film on which the protective film is laminated is likely to be deformed under the influence of various factors described above. Therefore, when a laminated body with an HC film is obtained by using an HC film from a laminated film roll using a protective film having self-adhesiveness, the standard deviation of the film thickness distribution in the winding axis direction is small as this HC film. By using the thing, the streak which occurs in the laminated body with HC film can be suppressed suitably.

In the laminated film roll, the standard deviation of the film thickness distribution in the winding axis direction of the laminated film is preferably 0.68 μm or less, may be 0.65 μm or less, and may be 0.60 μm or less. Good. The standard deviation of the film thickness distribution in the winding axis direction (width direction) of the laminated film can be measured by the method described in Examples described later. When the standard deviation of the film thickness distribution in the winding axis direction of the laminated film is large, it is considered that the HC film also undergoes the above-described deformation with a larger deformation amount. The standard deviation of is preferably small. The standard deviation of the film thickness distribution in the winding axis direction of the laminated film is adjusted by adjusting the standard deviation of the film thickness distribution as the HC film or the protective film before being made into the laminated film, of the base material layer before being made into the HC film. A laminated film that adjusts the standard deviation of the film thickness distribution, adjusts the lamination conditions when the HC film and the protective film are laminated to obtain a laminated film (tension applied to the HC film and the protective film during lamination), It can be adjusted by adjusting the tension at the time of winding.

(Laminate with hard coat film (laminate with HC film) and polarizing plate)
The laminated body with the HC film of the present embodiment has an adherend and an HC film separated from the laminated film on which the laminated film winding body described above is unwound. The laminated body with the HC film is obtained by peeling the protective film from the laminated film on which the laminated film winding body is unwound to obtain an HC film, and laminating the HC film and an adherend via an adhesive layer. Can be obtained by By using the HC film described above, it is possible to obtain a laminate with an HC film in which generation of streaks on the HC film side is suppressed.

The adherend is not particularly limited as long as it is an article that is required to have an increased surface hardness and prevent scratches on the surface. For example, an optical element such as a polarizing layer; a touch panel display; a panel of an image display device such as a liquid crystal display or an organic EL display; a front case, a rear case, a battery of a portable electronic device such as a smartphone, a tablet terminal, a music player, or a laptop computer. Cases; lenses such as goggles and glasses; optical recording media such as CDs, DVDs and Blu-ray discs; decorative sheets for building materials; automotive glass, headlights, exterior parts, interior parts, electrical parts, sunroofs, etc. In particular, when the base material layer forming the HC film is a transparent base material, it can be suitably used for optical applications such as optical elements, panels for image display devices, and optical recording media. When the adherend is a polarizing layer, the laminate with the HC film having the polarizing layer and the HC film can be used as a polarizing plate.

Examples of the adhesive layer for laminating the HC film and the adherend include an adhesive layer using an adhesive and an adhesive layer using an adhesive layer. The adhesive layer is usually one layer, but may be two or more layers.

When the laminate with the HC film is a polarizing plate (when the adherend is the polarizing layer), the polarizing layer and the HC film are preferably laminated via an adhesive layer. In the polarizing plate, the HC film may be provided on one surface of the polarizing layer via the adhesive layer, or the HC film may be provided on both surfaces of the polarizing layer via the adhesive layer. Further, an HC film is provided on one surface of the polarizing layer via an adhesive layer, and a base material layer having no HC layer different from the HC film is protected via the adhesive layer on the other surface. You may provide as a layer.

Hereinafter, the details of the laminated film roll, the laminated body with a hard coat film, the polarizing plate, and the layers forming these described above will be further described.

(Rolled film roll)
The laminated film roll can be obtained, for example, by winding the laminated film around a core so that the protective film side of the laminated film, which will be described later, is the outer surface. The length of the laminated film roll in the winding axis direction is not particularly limited, but is usually 800 mm or more and 2000 mm or less, 1000 mm or more, 1200 mm or more, and 1800 mm or less. It may be 1500 mm or less. The diameter of the laminated film roll is not particularly limited, but is usually 50 mm or more and 1000 mm or less, 100 mm or more, 300 mm or more, 800 mm or less, and 500 mm or less. May be.

(Laminated film)
The laminated film in the laminated film roll has a length in the winding axis direction (width direction) of, for example, 800 mm or more and 2000 mm or less, 1000 mm or more, 1200 mm or more, and 1800 mm. It may be less than or equal to 1500 mm. In addition, the length (roll length) of the laminated film in the laminated film roll may be, for example, 1000 m or more and 5000 m or less, and may be 1500 m or more, 2000 m or more, and 4500 m or less. Or may be 4000 m or less.

The laminated film can be formed by laminating an HC film and a protective film. The protective film may be attached to the HC layer side or the base material layer side of the HC film by utilizing the adhesiveness of the protective film (the adhesive layer when the adhesive layer is provided).

(Hard coat film (HC film))
The base material layer forming the HC film is used for protecting the surface of the adherend and supporting the HC layer. The base material layer is not particularly limited, but is preferably a resin film. When the HC film is used by being laminated on an optical film such as a polarizing layer, it is formed of a thermoplastic resin having excellent transparency, mechanical strength, thermal stability, moisture barrier property, isotropic property, stretchability and the like. It is preferable to use a resin film. Specific examples of such a thermoplastic resin include cellulose resins such as triacetyl cellulose; polyester resins such as polyethylene terephthalate and polyethylene naphthalate; polyether sulfone resins; polysulfone resins; polycarbonate resins; polyamides such as nylon and aromatic polyamides. Resin: Polyimide resin; Polyolefin resin such as polyethylene, polypropylene, ethylene/propylene copolymer; Cyclic polyolefin resin having cyclo- and norbornene structure (also referred to as norbornene-based resin); (meth)acrylic resin; Polyarylate resin; Polystyrene resin A polyvinyl alcohol resin and a mixture thereof can be mentioned. In addition, in this specification, "(meth)acrylic" means that either acrylic or methacrylic may be used. “(Meth)” such as (meth)acrylate has the same meaning.

The HC layer forming the HC film is used for increasing the surface hardness of the base material layer and preventing scratches on the surface. Examples of the material for forming the HC layer include a photo-curable resin, a thermosetting resin, and an electron beam-curable resin. Of these, the photo-curable resin is preferable.

As the photocurable resin, it is preferable to use a (meth)acrylic photocurable resin, for example, a polyfunctional (meth)acrylate; a polyfunctional urethanated (meth)acrylate, a polyol (meth)acrylate, and, if necessary, Accordingly, a photocurable mixture containing a (meth)acrylic polymer having an alkyl group containing two or more hydroxyl groups can be used. Among these, the photocurable mixture is preferable from the viewpoint of adhesiveness to the base material layer and productivity.

Examples of the polyfunctional (meth)acrylate include di- or tri-(meth)acrylate of trimethylolpropane, tri- or tetra-(meth)acrylate of pentaerythritol, and (meth) having at least one hydroxyl group in the molecule. A polyfunctional urethane-ized (meth)acrylate which is a reaction product of an acrylate and a diisocyanate is mentioned. These polyfunctional (meth)acrylates may be used alone or in combination of two or more.

The polyfunctional urethanized (meth)acrylate used when forming the photocurable resin mixture is produced using, for example, (meth)acrylic acid and/or (meth)acrylic acid ester, polyol, and diisocyanate. It Specifically, by preparing a hydroxy(meth)acrylate having at least one hydroxyl group in the molecule from (meth)acrylic acid and/or (meth)acrylic acid ester and polyol, and reacting this with diisocyanate, Polyfunctional urethanized (meth)acrylates can be produced. The polyfunctional urethane-ized (meth)acrylate produced in this way has a function as the above-mentioned photocurable resin. In the production, the (meth)acrylic acid and/or the (meth)acrylic acid ester may be used alone or in combination of two or more, and the polyol and the diisocyanate are also respectively You may use 1 type and may use it in combination of 2 or more type.

As the (meth)acrylic acid ester used when forming the polyfunctional urethane-modified (meth)acrylate, a chain or cyclic alkyl ester of (meth)acrylic acid can be used, and specific examples thereof include methyl ( Alkyl (meth)acrylates such as (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate; cycloalkyl (meth)acrylates such as cyclohexyl (meth)acrylate Can be mentioned.

The polyol used in forming the polyfunctional urethane-(meth)acrylate is a compound having at least two hydroxyl groups in the molecule, and specific examples thereof include ethylene glycol, propylene glycol, 1,3-propanediol, Diethylene glycol, dipropylene glycol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, 1,9-nonanediol, 1,10-decanediol, 2,2,4 -Trimethyl-1,3-pentanediol, 3-methyl-1,5-pentanediol, neopentyl glycol ester of hydroxypivalic acid, cyclohexanedimethylol, 1,4-cyclohexanediol, spiroglycol, tricyclodecanedimethylol, Hydrogenated bisphenol A, ethylene oxide-added bisphenol A, propylene oxide-added bisphenol A, trimethylolethane, trimethylolpropane, glycerin, 3-methylpentane-1,3,5-triol, pentaerythritol, dipentaerythritol, tripentaerythritol , Glucose and the like.

The diisocyanate used when forming the polyfunctional urethane-ized (meth)acrylate is a compound having two isocyanato groups (-NCO) in the molecule, and various aromatic, aliphatic or alicyclic diisocyanates are used. And specific examples thereof include tetramethylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 2,4-tolylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, 3,3'-dimethyl. Examples include -4,4'-diphenyl diisocyanate, xylene diisocyanate, trimethylhexamethylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and nuclear hydrogenated products of diisocyanates having an aromatic ring among these.

The (meth)acrylic polymer having an alkyl group containing two or more hydroxyl groups used when forming the photocurable resin mixture is one having an alkyl group containing two or more hydroxyl groups in one structural unit, Specific examples thereof include a polymer containing 2,3-dihydroxypropyl(meth)acrylate as a constituent unit, and a polymer containing 2-hydroxyethyl(meth)acrylate as a constituent unit together with 2,3-dihydroxypropyl(meth)acrylate. Etc.

The (meth)acrylic photocurable resin is preferably used as a photocurable resin composition in combination with a photopolymerization initiator. If necessary, additives such as leveling agents, antioxidants, antioxidants, ultraviolet absorbers, light stabilizers, antistatic agents, leveling agents, defoaming agents, etc. are added to the photocurable resin composition. You can also

For the HC layer, a hard coat liquid containing a solvent (hereinafter, may be referred to as “HC liquid”) is applied to one surface of a base material layer, the HC liquid is dried, and the dried HC liquid is cured. Can be formed by. The HC liquid can be prepared by adding a solvent to the photocurable resin composition and mixing them. The solvent can be appropriately selected from organic solvents capable of dissolving the components constituting the photocurable resin composition. The method of applying the HC liquid is not particularly limited, and a method known in the art such as a method of applying using a bar coater or a method of applying by spraying using a spray or the like can be used. The HC liquid applied to the base material layer can be dried by, for example, heat drying, vacuum drying, air drying, or the like. The method for curing the dried HC liquid may be appropriately selected depending on the material forming the HC layer, and examples thereof include a method of irradiating active energy rays such as ultraviolet rays and electron beams, and a method of heating.

(Protective film)
The protective film can be used to protect the surface of the HC layer of the HC film and to prevent the HC layer and the base material layer from blocking when the HC film is used as a wound body. It may also be provided on the surface of the base material layer. The protective film preferably has a resin film, and when the resin film does not have self-adhesiveness, it may have an adhesive layer for sticking to the HC film. The resin film forming the protective film is not particularly limited, and examples thereof include a film formed of a thermoplastic resin for forming the base material layer forming the HC film. Further, the protective film having self-adhesiveness can be formed by using, for example, polypropylene resin and polyethylene resin. As the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer that the protective film may have, for example, those described below can be used.

The thickness of the protective film is not particularly limited, but may be, for example, 5 μm or more and 200 μm or less, may be 10 μm or more, may be 20 μm or more, may be 25 μm or more, and may be 150 μm or less. Or 120 μm or less, or 100 μm or less. When the protective film has a pressure-sensitive adhesive layer, the thickness of the pressure-sensitive adhesive layer may be, for example, 5 μm or more and 100 μm or less, may be 10 μm or more, may be 15 μm or more, and may be 50 μm or less. It may be present or may be 40 μm or less. The thickness of the protective film or the pressure-sensitive adhesive layer can be measured according to the method for measuring the thickness of the HC film described in Examples below.

(Polarizing layer)
The polarizing layer may be a polyvinyl alcohol-based resin film (hereinafter, also referred to as “PVA-based resin film”) in which a dichroic dye such as iodine is adsorbed and aligned. It may be a layer in which the dichroic dye is oriented.

The PVA-based resin film is a film formed using a polyvinyl alcohol-based resin. The polyvinyl alcohol-based resin means a resin containing 50% by mass or more of constituent units derived from vinyl alcohol. As the polyvinyl alcohol-based resin, a saponified polyvinyl acetate-based resin can be used. The saponification degree of the polyvinyl acetate-based resin can be determined according to JIS K 6727 (1994), and can be in the range of 80.0 to 100.0 mol%, for example.

Examples of the polyvinyl acetate-based resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and a copolymer of vinyl acetate and another monomer copolymerizable therewith. Examples of the other monomer copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and ammonium group-containing (meth)acrylamides.

An example of the PVA-based resin film may be an unstretched film obtained by forming a polyvinyl alcohol-based resin, or a stretched film obtained by stretching this unstretched film. When the PVA-based resin film is a stretched film, it is preferably a vertically uniaxially stretched stretched film, and preferably a dry stretched stretched film. When the PVA-based resin film is a stretched film, the stretching ratio is usually 1.1 to 8 times.

The polarizing layer, which is a layer in which the dichroic dye is oriented in the liquid crystal compound, is, for example, one in which the dichroic dye is oriented in the polymerizable liquid crystal compound and the cured layer is obtained by polymerizing the polymerizable liquid crystal compound. Can be mentioned. Such a polarizing layer is obtained by applying a composition for forming a polarizing layer containing a polymerizable liquid crystal compound and a dichroic dye on a substrate film, and polymerizing and curing the polymerizable liquid crystal compound while maintaining the liquid crystal state. Can be formed. The polarizing layer thus obtained is in a state of being laminated on the substrate film, and the substrate film is directly provided on the other surface of the polarizing layer (the surface opposite to the side on which the HC film is provided). You may use as a protective layer. Alternatively, the base film may be peeled off after the base film-attached polarizing layer in which the base film can be peeled from the polarizing layer is laminated on the HC film via the adhesive layer.

(Adhesive layer)
Examples of the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer include pressure-sensitive adhesives called so-called pressure-sensitive adhesives, and conventionally known pressure-sensitive adhesives can be used without particular limitation. As the pressure-sensitive adhesive, for example, a pressure-sensitive adhesive having a (meth)acrylic-based, urethane-based, silicone-based, polyvinyl ether-based base polymer or the like can be used. Further, it may be an active energy ray-curable adhesive, a thermosetting adhesive, or the like. Among these, a pressure-sensitive adhesive using a (meth)acrylic resin as a base polymer, which is excellent in transparency, adhesive strength, removability (hereinafter, also referred to as reworkability), weather resistance, heat resistance, etc., is preferable.

(Adhesive layer)
As the adhesive forming the adhesive layer, for example, one or more of water-based adhesives, active energy ray-curable adhesives, pressure-sensitive adhesives, and the like can be formed in combination. Examples of the water-based adhesive include a polyvinyl alcohol-based resin aqueous solution and a water-based two-component urethane-based emulsion adhesive. The active energy ray-curable adhesive is an adhesive that is cured by irradiation with active energy rays such as ultraviolet rays, for example, one containing a polymerizable compound and a photopolymerizable initiator, one containing a photoreactive resin, Examples thereof include those containing a binder resin and a photoreactive crosslinking agent. Examples of the polymerizable compound include photopolymerizable monomers such as photocurable epoxy-based monomers, photocurable (meth)acrylic-based monomers, and photocurable urethane-based monomers, and oligomers derived from these monomers. .. Examples of the photopolymerization initiator include those containing a substance that emits active species such as neutral radicals, anion radicals, and cation radicals upon irradiation with active energy rays such as ultraviolet rays.

Hereinafter, the present invention will be described more specifically by showing Examples and Comparative Examples, but the present invention is not limited to these Examples.

[Measurement of thickness of hard coat film (HC film)]
Using a contact-type film thickness meter (Digimicro MH-15M, manufactured by Nikon Corporation), the total of the position 50 mm inside and the center position in the width direction from both ends of the HC film in the winding axis direction (width direction). The thickness was measured at three locations, and the average value was used as the thickness of the HC film.

[Measurement of Tensile Elastic Modulus of Hard Coat Film (HC Film)]
A rectangular test piece with a length of 100 mm in the winding direction (the length direction of the HC film) and a length of 25 mm in the winding axis direction (the width direction of the HC film) is cut out from the center of the winding direction of the HC film. It was Then, each of the cut-out test pieces was subjected to the long-side direction ( Winding direction) Both ends are sandwiched, the test piece is pulled in the long side direction at a pulling speed of 1 mm/min in an environment of a temperature of 23° C. and a relative humidity of 55%. The tensile elastic modulus [MPa] in MD at °C was calculated.

[Measurement of standard deviation of film thickness distribution]
The standard deviation of the film thickness distribution in the winding axis direction of the HC film, the protective film, and the laminated film obtained from the laminated film roll was measured by the following procedure. Using a non-contact type continuous film thickness meter (tabletop offline capacitance type thickness measuring device TOF-C, manufactured by Yamabun Electric Co., Ltd.) from one end in the winding axis direction (width direction) of each film The thickness was measured at a pitch of 1 mm up to the other end (width 1330 mm) and the standard deviation was calculated from the measured value.

[Measurement of pencil hardness]
The pencil hardness of the HC film was measured on a glass plate with the HC layer side facing up according to the pencil hardness test defined in JIS K5600-5-4:1999.

[Example 1]
The protective film was laminated on the HC layer of the HC film such that the tension of the protective film (tension before lamination) was 0.045 N/mm, and the obtained laminated film was wound to form a laminated film roll ( 1) was prepared. The protective film was a self-adhesive polyethylene film (FF1035, manufactured by Tredegar Co., Ltd., thickness: 28 μm). In the HC film, the substrate layer was a (meth)acrylic resin film having a thickness of 25 μm, and the HC layer was a layer of (meth)acrylic ultraviolet curable resin having a thickness of 3 μm. The thickness, tensile modulus, standard deviation of film thickness distribution, and pencil hardness of the HC film peeled from the laminated film obtained by unwinding the laminated film roll (1) were measured. The standard deviation of the film thickness distribution of the laminated film obtained by unwinding the laminated film roll (1) and the protective film peeled from the laminated film was measured. The results are shown in Table 1.

Next, as a polarizing layer, a polyvinyl alcohol-based resin film (PVA-based resin film) in which iodine, which is a dichroic dye, was adsorbed and oriented was prepared. On this polarizing layer, the base material layer side of the HC film peeled from the laminated film obtained by unwinding the laminated film roll (1) was laminated with an aqueous adhesive to obtain a polarizing plate (1). It was As the above-mentioned water-based adhesive, polyvinyl alcohol powder [trade name "Gosephimmer" manufactured by Nippon Synthetic Chemical Industry Co., Ltd., average degree of polymerization: 1100] was dissolved in hot water at 95°C to obtain a concentration of 3% by weight. % Polyvinyl alcohol aqueous solution, an aqueous solution was used in which a crosslinking agent [sodium glyoxylate manufactured by Japan Synthetic Chemical Industry Co., Ltd.] was mixed at a ratio of 1 part by weight to 10 parts by weight of polyvinyl alcohol powder. The thickness of the adhesive layer was 0.1 μm. When the obtained polarizing plate (1) was visually observed from the HC film side, no streak was visually observed.

[Comparative Example 1]
A laminated film roll (2) was prepared in the same manner as in Example 2 except that the tension of the protective film (tension before lamination) was adjusted to 0.090 N/mm. The thickness, tensile modulus, standard deviation of film thickness distribution, and pencil hardness of the HC film peeled from the laminated film obtained by unwinding the laminated film roll (2) were measured. The standard deviation of the film thickness distribution of the laminated film obtained by unwinding the laminated film roll (2) and the protective film peeled from the laminated film was measured. The results are shown in Table 1.

Next, a polarizing plate (2) was obtained in the same procedure as in Example 1. When the obtained polarizing plate (2) was visually observed from the HC film side, a streak in the direction along the winding direction in the laminated film wound body (2) was visually recognized.

[Reference Example 1]
The same procedure as in Comparative Example 1 was repeated except that the base material layer was a triacetylcellulose film having a thickness of 25 μm and the HC layer was a layer of a (meth)acrylic UV-curing resin having a thickness of 3 μm. To prepare a laminated film roll (3). The thickness, the tensile elastic modulus, the standard deviation of the film thickness distribution, and the pencil hardness of the HC film peeled from the laminated film obtained by unwinding the laminated film roll (3) were measured. The standard deviation of the film thickness distribution of the laminated film obtained by unwinding the laminated film roll (3) and the protective film peeled from the laminated film was measured. The results are shown in Table 1.

Next, a polarizing plate (3) was obtained in the same procedure as in Example 1. When the obtained polarizing plate (3) was visually observed from the HC film side, no streak was visually observed.

Claims (9)

A laminated film winding body in which a laminated film is wound into a roll,
The laminated film has a hard coat film having a base layer and a hard coat layer, and a protective film,
The thickness of the hard coat film is 30 μm or less,
The tensile elastic modulus at a temperature of 23° C. and a relative humidity of 55% in the winding direction of the hard coat film is 3000 MPa or less,
The standard deviation of the film thickness distribution in the winding axis direction of the hard coat film peeled from the laminated film is 0.25 μm or less,
The laminated film wound body, wherein the pencil hardness of the hard coat film separated from the laminated film is 5B or more and less than H. The laminated film winding body according to claim 1, wherein the protective film is provided on the hard coat layer side of the hard coat film. The laminated film winding body according to claim 1, wherein the protective film is provided on the base layer side of the hard coat film. The laminated film wound body according to any one of claims 1 to 3, wherein a standard deviation of a film thickness distribution in a winding axis direction of the protective film peeled from the laminated film is 0.68 µm or less. The laminated film wound body according to claim 1, wherein the protective film has self-adhesiveness. The laminated film wound body according to any one of claims 1 to 5, wherein a standard deviation of a film thickness distribution in a winding axis direction of the laminated film is 0.68 µm or less. A laminate with a hard coat film, comprising the hard coat film peeled from the laminate film according to any one of claims 1 to 6 and an adherend. The laminate with a hard coat film according to claim 7, wherein the hard coat film separated from the laminate film and the adherend are laminated via an adhesive layer. A polarizing plate comprising a hard coat film and a polarizing layer, which are separated from the laminated film according to claim 1.