KR20190100168A - Manufacturing Method of Optical Film, Polarizing Plate, and Display Device - Google Patents

Abstract

It includes the peeling process of providing a multilayer film to a peeling process, The said multilayer film contains the film (A) which consists of thermoplastic resin A, and the film (B) formed in the one or both surfaces of the said film (A). It is a multilayer film, The said peeling process includes peeling the said film (B) so that a force may be applied to the thickness direction of the said film (A) from the said film (A) in temperature Tov (degreeC), The said temperature Tov and the glass transition temperature TgA (degreeC) of the said film (A) satisfy | fill the relationship of Tov≥TgA, and the said film (A) and the said film (B) at the temperature Tov in the said multilayer film The peeling force Pa of) is 0.03 N / 50 mm or more and 0.5 N / 50 mm or less, the manufacturing method of an optical film; And a polarizing plate and a display device using the optical film.

Description

Manufacturing Method of Optical Film, Polarizing Plate, and Display Device

This invention relates to the manufacturing method of an optical film, a polarizing plate, and a display apparatus.

In display devices, such as a liquid crystal display device, forming the optical film made of resin which has a phase difference for the purpose of optical compensation, etc. is widely performed. As a method of providing a phase difference to the resin film, extending | stretching such a film is widely performed.

As such an optical film, a film in which the NZ coefficient Nz satisfies 0 <Nz <1, preferably a film of 0.4 <Nz <1, more preferably a film of Nz = 0.5, may be required. However, when the film is stretched by the usual method, the value of the NZ coefficient is smaller than 0 or greater than 1, and therefore it is difficult to obtain a film with 0 <Nz <1.

As a method of obtaining the film of 0 <Nz <1, it is possible to employ | adopt the multilayer film which combined several films. However, it is required to realize a film of 0 <Nz <1 with a simpler single layer structure.

The method of patent document 1 is known as a method of realizing the film of 0 <Nz <1 by the film of a single | mono layer. In patent document 1, a shrink film is bonded to the resin film of a process target, a shrink film is shrunk after that, and a resin film is shrunk by that, and 0 <Nz <1 is achieved as a result.

(Patent Document 1) Japanese Unexamined Patent Publication No. Hei 08-207119 (corresponding foreign publication: European Patent Application Publication No. 0707938)

However, with the method described in Patent Document 1, it is difficult to control the shrinkage force of the shrink film, the process of shrinking the shrink film is complicated, and it is difficult to easily manufacture a film of 0 <Nz <1.

Therefore, the objective of this invention is providing the manufacturing method of an optical film which can manufacture easily the optical film of 0 <Nz <1. Another object of the present invention is to provide a polarizing plate which can be easily manufactured and has a high optical compensation function, and a display device which can be easily manufactured and has high optical compensation.

This inventor examined in order to solve said subject. As a result, this inventor discovered that such a subject can be solved by extending | stretching a film to thickness direction using the peeling force of a film as a manufacturing method of the optical film which has not existed so far. Moreover, it was discovered that favorable thickness direction extending | stretching operation can be performed by making the characteristic of the temperature which performs extending | stretching in such a thickness direction, and the characteristic of the multilayer film provided to peeling specific. This invention is made | formed based on this knowledge.

That is, this invention is as follows.

[1] including a peeling step of providing the multilayer film to the peeling treatment,

The said multilayer film is a multilayer film containing the film (A) which consists of thermoplastic resin A, and the film (B) formed in the one or both surfaces of the said film (A),

The peeling treatment includes peeling the film (B) from the film (A) at a temperature Tov (° C.) so that a force is applied in the thickness direction of the film (A),

The temperature Tov and the glass transition temperature TgA (° C.) of the film A satisfy a relationship of Tov ≧ TgA,

In the said multilayer film, peeling force Pa of the said film (A) and the said film (B) in temperature Tov is 0.03 N / 50 mm or more and 0.5 N / 50 mm or less,

Method for producing an optical film.

[2] The method for producing an optical film according to [1], wherein the thermoplastic resin A contains an alicyclic structure-containing polymer.

[3] The method for producing an optical film according to [1] or [2], further comprising an stretching step of stretching the multilayer film in the in-plane direction.

[4] A polarizing plate comprising an optical film and a polarizer produced by the production method according to any one of [1] to [3].

[5] A display device comprising the optical film produced by the production method according to any one of [1] to [3].

According to this invention, the manufacturing method of the optical film which can manufacture the optical film of 0 <Nz <1 easily; A polarizing plate which can be easily manufactured and has a high optical compensation function; And a display device which can be easily manufactured and has high optical compensation.

1: is a side view which showed typically an example of the peeling apparatus which performs the peeling process in the manufacturing method of this invention, and the peeling process operation using the said apparatus.
FIG. 2: is a side view which showed typically the peeling apparatus which performs the peeling process in the manufacturing method of this invention, and another example of the peeling process operation using the said apparatus.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment and illustration about this invention are shown and it demonstrates in detail. However, this invention is not limited to embodiment and illustration shown below, It can implement by changing arbitrarily in the range which does not deviate from the Claim of this invention, and the range of the equality.

In the following description, unless otherwise indicated, in-plane retardation Re of a film is a value represented by Re = (nx-ny) xd, and unless otherwise mentioned, retardation Rth of the thickness direction of a film is mentioned. , Rth = ｛(nx + ny) / 2-nz'x d. In addition, NZ coefficient Nz of a film is a value represented by Nz = (nx-nz) / (nx-ny), and can also be represented by Nz = (Rth / Re) +0.5. Here, nx is a direction perpendicular | vertical to the in-plane direction of a film, ie, the thickness direction, and shows the refractive index of the direction which gives the largest refractive index. ny represents the refractive index of the said in-plane direction and the direction orthogonal to the direction of nx. nz represents the refractive index of the thickness direction. d represents the thickness of a film. The measurement wavelength is 590 nm unless otherwise noted.

In the following description, unless otherwise stated, a "polarizing plate" includes not only a rigid member but also a member having flexibility, such as a film made of resin, for example.

In the following description, a "long" film refers to a film having a length of 5 times or more with respect to a width, and preferably has a length of 10 times or more, and specifically, is wound and stored or transported on a roll. Refers to a film having a length of about. Although the upper limit of the length of a long film does not have a restriction | limiting in particular, For example, it can be 100,000 times or less with respect to width.

In the art, "stretching" of a film usually means an operation of deforming the film so as to expand the shape of the film in one or more directions of the in-plane direction of the film. However, in this application, the "stretching" of a film is not limited to this, The film is deformed so that the shape of a film may be extended to directions other than the in-plane direction (direction parallel to the surface direction of a film, for example, thickness direction etc.). It also includes the operation to make it. In the following description, when it is clear from the context, the operation of deforming the film so as to expand the shape of the film in one or more directions in the in-plane direction of the film is simply referred to as "stretching". On the other hand, the process of deforming the film so as to extend the shape of the film in a direction other than the in-plane direction is referred to as "thickness direction stretching" to distinguish it from such normal "stretching", and the film which passed this process is "thickness direction stretching". Film ”.

[One. Manufacturing Method of Optical Film]

The manufacturing method of the optical film of this invention includes the peeling process of providing a specific multilayer film to a specific peeling process.

[One. 1. Multilayer Film]

The multilayer film provided to a peeling process is a multilayer film containing the film (A) which consists of thermoplastic resin A, and the film (B) provided in one or both of the film (A).

[One. 1. 1. Film (A)]

The thermoplastic resin A constituting the film (A) is not particularly limited, and a resin containing various polymers capable of imparting desired physical properties as an optical film can be appropriately selected and adopted.

As a preferable example of the polymer contained in the thermoplastic resin A, an alicyclic structure containing polymer is mentioned.

The alicyclic structure-containing polymer is a polymer having an alicyclic structure in the repeating unit, and both a polymer containing an alicyclic structure in the main chain and a polymer containing an alicyclic structure in the side chain can be used. An alicyclic structure containing polymer can contain crystalline resin and an amorphous polymer. From the viewpoint of obtaining the desired effect of the present invention and the production cost, an amorphous alicyclic structure-containing polymer is preferable.

As an alicyclic structure which an amorphous alicyclic structure containing polymer has, a cycloalkane structure and a cycloalkene structure are mentioned, for example, A cycloalkane structure is preferable from a viewpoint of thermal stability.

Although there is no restriction | limiting in particular in the carbon number which comprises the repeating unit of one alicyclic structure, Usually, 4-30, Preferably it is 5-20, More preferably, it is 6-15.

The proportion of the repeating unit having an alicyclic structure in the alicyclic structure-containing polymer is appropriately selected depending on the intended use, but is usually at least 50% by weight, preferably at least 70% by weight, more preferably at least 90% by weight. By increasing the number of repeating units which have an alicyclic structure in this way, the heat resistance of a base film can be improved.

Specific examples of the alicyclic structure-containing polymer include (1) norbornene polymers, (2) monocyclic cyclic olefin polymers, (3) cyclic conjugated diene polymers, (4) vinyl alicyclic hydrocarbon polymers, and hydrides thereof. Can be mentioned. Among these, norbornene polymers and their hydrides are more preferable from the viewpoint of transparency and moldability.

As a norbornene polymer, For example, the ring-opening polymer of a norbornene monomer, the ring-opening copolymer of the other monomer which can ring-open copolymerize with a norbornene monomer, and these hydrides; The addition polymer of a norbornene monomer, the addition polymer of the other monomer copolymerizable with a norbornene monomer, etc. are mentioned. Among these, the ring-opening polymer hydride of a norbornene monomer is especially preferable from a transparency viewpoint.

As an example of the said alicyclic structure containing polymer, the polymer disclosed by Unexamined-Japanese-Patent No. 2002-321302 is mentioned, for example.

Moreover, the polymer disclosed by Unexamined-Japanese-Patent No. 2016-26909 is mentioned as an example of a crystalline alicyclic structure containing polymer.

As another example of the polymer contained in the thermoplastic resin A, general purpose polymers, such as a triacetyl cellulose and a polystyrene polymer, are mentioned. In particular, among the polystyrene-based polymers, in particular, a polystyrene-based polymer having a syndiotactic structure can be preferably employed. As an example of the polystyrene polymer which has a syndiotactic structure, the polymer disclosed by Unexamined-Japanese-Patent No. 2014-186273 is mentioned.

Although the weight average molecular weight of the polymer contained in the thermoplastic resin A is not specifically limited, Preferably it is 10,000 or more, More preferably, it is 20,000 or more, On the other hand, Preferably it is 300,000 or less, More preferably, it is 250,000 or less. When the weight average molecular weight is within this range, the thermoplastic resin A excellent in mechanical strength and molding processability can be easily obtained.

Although thermoplastic resin A may consist only of polymers which are main components, such as those mentioned above, as long as the effect of this invention is not impaired remarkably, you may include arbitrary compounding agents. The ratio of the polymer which is a main component in resin becomes like this. Preferably it is 70 weight% or more, More preferably, it is 80 weight% or more.

As the thermoplastic resin A, those having desired characteristics can be appropriately selected from various commercial products. As an example of such a commercial item, the brand name "Zeo Noah" (made by Nippon Xeon Corporation), a brand name "Topas" (made by Polyplastics Corporation), and a brand name "Aton" (made by JSR Corporation) are mentioned.

Glass transition temperature TgA of thermoplastic resin A becomes like this. Preferably it is 100 degreeC or more, More preferably, it is 110 degreeC or more, On the other hand, Preferably it is 180 degrees C or less, More preferably, it is 170 degrees C or less. When TgA is such a range, the process of thickness direction extending | stretching etc. can be performed smoothly, and the optical film which has a desired optical body characteristic can be obtained easily.

Preferably the thickness of the film (A) is 10 micrometers or more, More preferably, it is 20 micrometers or more, On the other hand, Preferably it is 200 micrometers or less, More preferably, it is 190 micrometers or less. When the thickness of the film A is such a range, the process of thickness direction extending | stretching etc. can be performed smoothly, and the optical film which has a desired optical body characteristic can be obtained easily.

The method of manufacturing a film (A) is not specifically limited, Any manufacturing method can be employ | adopted. For example, the film A can be manufactured by shape | molding thermoplastic resin A to a desired shape. Preferable examples of the molding method for molding the resin A include extrusion molding. By performing extrusion molding, the film (A) having a desired dimension can be efficiently produced.

[One. 1. 2. Film (B)]

It does not specifically limit as a material which comprises a film (B), Resin containing various polymers suitable for implementation of this invention can be selected suitably, and can be employ | adopted. Hereinafter, this resin is simply called "resin B."

As the resin B, a thermoplastic resin can be used. Examples of the polymer contained in the resin B and the preferred range of the molecular weight thereof include the same examples as those described above for the alicyclic structure-containing polymer and other polymers contained in the thermoplastic resin A.

Examples of the further layer of the alicyclic structure-containing polymer contained in the resin B include at least two polymer blocks having a cyclic hydrocarbon group-containing compound hydride unit [I], and a chain hydrocarbon compound hydride unit [II], or a unit [1] And hydrogenated block copolymers comprising at least one polymer block having a combination of] and unit [II]. Specific examples of such hydrogenated block copolymers include polymers disclosed in WO 2016/152871.

As an example of the further layer of the polymer contained in resin B, general-purpose polymers, such as a polypropylene, a (meth) acrylate polymer, and a polyimide, are mentioned. As resin B, what has a desired characteristic can be suitably selected among the various commercial items, and it can employ | adopt. As an example of such a commercial item, the self-adhesive stretched polypropylene film (For example, Fitamura Chemical Co., Ltd. make, brand name "FSA 010M # 30") is mentioned.

Preferably the thickness of the film (B) is 10 micrometers or more, More preferably, it is 15 micrometers or more, On the other hand, Preferably it is 100 micrometers or less, More preferably, it is 90 micrometers or less. When the thickness of the film (B) is such a range, the process of thickness direction extending | stretching etc. can be performed smoothly, and the optical film which has a desired optical body characteristic can be obtained easily.

The method of manufacturing the film (B) is not particularly limited, and any manufacturing method can be adopted. For example, the film B can be manufactured by forming resin B in a desired shape. Preferable examples of the molding method for forming the resin B include extrusion molding. By performing extrusion molding, the film (B) having a desired dimension can be efficiently produced.

[One. 1. 3. Other layers]

The multilayer film may include any layer in addition to the films (A) and (B). For example, it may include an adhesive layer. As an adhesive which comprises an adhesive layer, various adhesives commercially available can be used. Specifically, the adhesive containing an acrylic polymer can be used as a polymer which is a main component. For example, an adhesive layer is transferred to a film (A) or a film (B) from the film (for example, Fujimori Industrial Co., Ltd. "Mastack series") which has a commercially available adhesive layer, and this is an adhesive layer in a multilayer film. It is available.

When a multilayer film has an adhesive layer between films (A) and (B), it is preferable that the adhesive force with respect to the film (B) of such an adhesive layer is higher than the adhesive force with respect to the film (A). By having such a difference of adhesive force, the remainder of the paste with respect to an optical film can be reduced, and a high quality optical film can be obtained easily. Such a difference in adhesive force can be obtained by appropriately selecting the material of the pressure-sensitive adhesive layer and by performing appropriate surface treatment on the surfaces of the films (A) and (B) as necessary.

[One. 1. 4. Peeling force]

In the manufacturing method of this invention, as a multilayer film, the peeling force Pa of the film (A) and the film (B) in temperature Tov uses what is a value within a specific range. Here, temperature Tov is the temperature of the film in the peeling process of the manufacturing method of this invention.

Peel force Pa is 0.03 N / 50 mm or more, preferably 0.035 N / 50 mm or more, more preferably 0.04 N / 50 mm or more, while 0.5 N / 50 mm or less, preferably 0.4 N / 50 mm or less, more preferably Is 0.3 N / 50 mm or less. By the peeling force being in this range, generation | occurrence | production of the wrinkle in the process to a peeling process is suppressed, the unintentional peeling of the film B in the step before a peeling process is suppressed, and also the surface of the film A Good peeling in can be achieved and the optical film of a good quality can be manufactured smoothly.

Peeling force Pa can be calculated | required by performing a 180 degree peeling test with respect to a multilayer film. The 180 degree peeling test cuts out a multilayer film, makes it into the slice of the longitudinal direction x width direction = 300 mm x 50 mm, and puts it in the constant temperature / humidity tank mounting tensile tester (for example, "5564 type made by Instron"), Can be carried out at a temperature Tov. Specifically, the film A is gripped by one chuck of the measuring device, the film B is gripped by the other chuck, and the peel test can be performed under conditions of a tensile speed of 300 mm / min.

[One. 1. 5. Preparation method of multilayer film]

The method of preparing the multilayer film provided for the manufacturing method of this invention is not specifically limited, Arbitrary methods can be employ | adopted. Such preparation can be performed, for example by bonding together the film (A) and the film (B). Prior to bonding, if necessary, the film A and / or the film B may be subjected to surface treatment such as corona treatment. In addition, prior to bonding, an adhesive layer can be formed in the surface of the film (A) and / or the film (B) as needed, and bonding can be performed through this adhesive layer. Bonding can be performed by bonding a long film (A) and a long film (B) with a roll-to-roll along the longitudinal direction.

[One. 2. Peeling process

In the peeling process in the manufacturing method of this invention, a multilayer film is provided to a peeling process. The peeling process includes peeling the film (B) from the film (A). By performing such peeling process, the force which pulls the film A in the thickness direction can be applied, and as a result, the thickness direction extending | stretching of the film A can be achieved. When a multilayer film has two or more layers of film (B), the film (B) of multiple layers peels normally simultaneously.

1: is a side view which showed typically an example of the peeling apparatus which performs the peeling process in the manufacturing method of this invention, and the peeling process operation using the said apparatus. In FIG. 1, the long multilayer film 100 is conveyed in the arrow A11 direction, and is provided to the peeling process in the peeling area | region P after that.

The multilayer film 100 has a film (A) 131, a film (B) 111 formed on one surface of the film (A) 131, and another one of the film (A) 131. Film (B) 112 formed in the surface is included. The multilayer film 100 also includes the pressure-sensitive adhesive layers 121 and 122 interposed between the films (A) and (B). The thickness of the film (A) 131 in a multilayer film is shown by the arrow A14.

The peeling process in a peeling process can be performed by pulling the film B in the direction different from the in-plane direction of the film A conveyed. In the example of FIG. 1, in the peeling area | region P, the film (B) 111 is pulled in the arrow A12 direction along the longitudinal direction, and the film B (112) is further extended in the longitudinal direction. A tow is pulled in the direction of the arrow A13. Thereby, peeling advances from the downstream of the conveyance direction of a multilayer film to an upstream, and it can peel so that a force may be applied to the film (B) 111 and 112 in the thickness direction of the film (A) 131. The force in the thickness direction of the film here is a force in a direction parallel to the in-plane direction of the film, and is preferably a direction close to the direction perpendicular to the plane of the film. As a result of this peeling process, the optical film 132 extended | stretched in the thickness direction is obtained. In addition, by bringing the traction force in the direction of the arrow A12 and the traction force in the direction of the arrow A13 to be balanced, these tractions are imparted to the multilayer film 100 and the optical film 132 in an undesired in-plane direction. It can be done without.

In the example of FIG. 1, the thickness of the optical film 132 is shown by the arrow A15. The optical film 132 has thickness thicker than the film (A) 131 in the multilayer film 100 as a result of the thickness direction extending | stretching. However, the production method of the present invention is not limited thereto. For example, when a peeling process also involves extending | stretching to an in-plane direction, the thickness of an optical film does not necessarily become thicker than the thickness of the film A, but even in such a case, the optical film of 0 <Nz <1 This may be obtained.

The optical film 132 obtained as a result of the peeling process in the peeling region P is further conveyed in the arrow A11 direction. The multilayer film 100 and the optical film 132 are conveyed in the state held by the nip rolls 151 and 152 upstream of a peeling area | region, and the nip rolls 161 and 162 downstream of a peeling area | region. By adjusting the peripheral speed of these nip rolls suitably, a conveyance speed can be adjusted.

In addition, if necessary, the peripheral speed of the downstream nip roll can be adjusted at a speed faster than the peripheral speed of the upstream nip roll. By performing such adjustment, desired tension can be provided to the multilayer film 100 and the optical film 132. If necessary, by adjusting such tension, the stretching step in the film length direction with the peeling step can be performed. Or you may extend | stretch to arbitrary directions in a film plane with a peeling process or upstream or downstream of the peeling area | region P as needed.

In the manufacturing method of the optical film of this invention, in addition to thickness direction extending | stretching, the draw ratio at the time of performing extending | stretching of an in-plane direction can be adjusted suitably according to the desired optical performance requested | required to give to an optical film. The specific draw ratio is preferably 1 or more times, more preferably 1.01 times or more, while preferably 2 times or less, and more preferably 1.8 times or less. When the draw ratio of in-plane direction is such a range, desired optical performance can be obtained easily.

In a peeling apparatus WHEREIN: When performing a peeling process continuously with respect to a long multilayer film, peeling area | region P can be set to the position with a peeling device by making the conveyance speed and peeling speed of a multilayer film balanced. In this case, the conveyance speed of a multilayer film becomes a peeling speed. The peeling speed can be suitably adjusted in accordance with desired optical performance required to give to an optical film. The specific peeling speed is preferably 1 m / min or more, more preferably 2 m / min or more, while preferably 50 m / min or less, and more preferably 40 m / min or less. When the peeling rate is in this range, desired optical performance can be easily obtained.

In the manufacturing method of the optical film of this invention, a peeling process is performed at temperature Tov (degreeC). The temperature Tov and the glass transition temperature TgA (° C.) of the film A satisfy the relationship of Tov ≧ TgA. Tov becomes like this. Preferably it is (TgA + 3) degreeC or more, More preferably, it is (TgA + 5) degreeC or more. By adjusting Tov in such a range, optical characteristics, such as desired NZ coefficient, can be easily given to an optical film. Although the upper limit of Tov is not specifically limited, For example, it can be set to (TgA + 40) degrees C or less. The temperature Tov in a peeling process can be adjusted by heating the temperature in oven (not shown) which is important for the area | region containing a peeling area with a suitable heating apparatus.

FIG. 2: is a side view which showed typically the peeling apparatus which performs the peeling process in the manufacturing method of this invention, and another example of the peeling process operation using the said apparatus. In FIG. 2, the long multilayer film 200 is conveyed in the direction of an arrow A21, and is then provided to a peeling step in the peeling region P. The multilayer film 200 includes a film (A) 231 and a film (B) 211 formed on one surface of the film (A) 231, but another film (A) 231 The film B is not formed in one surface. The multilayer film 200 also includes the pressure-sensitive adhesive layer 221 interposed between the films (A) and (B). The thickness of the film (A) 231 in a multilayer film is shown by the arrow A24.

In this example, since the multilayer film 200 has the film (B) 211 only on one surface, the peeling process in a peeling process carries out the film (B) 211 which conveys such a film (B) 211. It carries out by pulling to the arrow A22 direction which is a direction different from the in-plane direction of A). Therefore, the nip rolls 151 and 152 upstream of the peeling region and the nip rolls 161 and 162 downstream of the peeling region give tension to the multilayer film 200 and the optical film 232 after the peeling process, and this tension By this, the traction of the film (B) 211 is opposed. As a result of this peeling process, the film (A) 231 is extended in the thickness direction, and the optical film 232 is obtained. The optical film 232 has the thickness shown by the arrow A25 thicker than the film (A) 231.

[2. Optical film]

According to the manufacturing method of this invention, the optical film whose NZ coefficient Nz is 0 <Nz <1 can be manufactured easily. Nz is more preferably 0.4 <Nz <1, and ideally Nz = 0.5. Although it is difficult to manufacture the optical film which has such an NZ coefficient by extending | stretching a film to a normal in-plane direction, it can be usefully used for the purpose of optical compensation of a display apparatus. Therefore, the manufacturing method of this invention shows a high effect from a viewpoint which can manufacture easily a useful product while being difficult to manufacture.

In-plane retardation Re of an optical film becomes like this. Preferably it is 100 nm or more, More preferably, it is 120 nm or more, On the other hand, Preferably it is 350 nm or less, More preferably, it is 300 nm or less. When Re is such a range, the optical film which can be usefully used for uses, such as optical compensation, can be comprised. Retardation Rth of the thickness direction of an optical film becomes like this. Preferably it is -80 nm or more, More preferably, it is -70 nm or more, On the other hand, Preferably it is 80 nm or less, More preferably, it is 70 nm or less. When Re is such a range, the optical film which has characteristics, such as desired Nz coefficient, can be usefully used for uses, such as optical compensation, can be comprised.

[3. Use of optical film: polarizer and display device]

The optical film obtained by the manufacturing method of this invention can be used as a component of optical apparatuses, such as a display apparatus. For example, optical components, such as a polarizing plate, can be comprised combining an optical film and another member.

The polarizing plate of this invention is equipped with the optical film and polarizer manufactured by the manufacturing method of the said invention. The polarizing plate of this invention can be manufactured by bonding an optical film and a polarizer.

Prior to bonding with a polarizing plate, arbitrary layers can be formed in the surface of an optical film. As an example of arbitrary layers, the hard-coat layer which raises the surface hardness of a film, the mat layer which improves the slidability of a film, and an antireflection layer are mentioned.

The polarizing plate of this invention may further be equipped with the adhesive bond layer for bonding these between the film cut out from the optical film and the polarizer.

The polarizer is not particularly limited, and any polarizer can be used. As a polarizer, what carried out extending | stretching after adsorbing members, such as an iodine and a dichroic dye, to a polyvinyl alcohol film is mentioned. As an adhesive agent which comprises an adhesive bond layer, what made various polymers the base polymer is mentioned. Examples of such base polymers include, for example, acrylic polymers, silicone polymers, polyesters, polyurethanes, polyethers, and synthetic rubbers.

A polarizing plate can be equipped with a protective film. Although the number of polarizers and protective films with which a polarizing plate is equipped is arbitrary, the polarizing plate of this invention can be normally equipped with one layer of polarizer and two layers of protective films formed on both surfaces. Among these two layers, the film cut out from the optical film of this invention may be sufficient as both, and the film cut out from the optical film of this invention may be sufficient as either one.

The display apparatus of this invention is equipped with the optical film manufactured by the manufacturing method of the said invention. The display device of the present invention may preferably include the polarizing plate of the present invention. The display device of the present invention can be appropriately configured by combining the optical film of the present invention with other components of the display device.

The display device of the present invention is preferably a liquid crystal display device. As the liquid crystal display device, for example, in-plane switching (IPS) mode, vertical alignment (VA) mode, multi-domain vertical alignment (MVA) mode, continuous pin wheel alignment (CPA) mode, hybrid alignment nematic (HAN) And a liquid crystal cell of a driving method such as a) mode, a twisted nematic (TN) mode, a super twisted nematic (STN) mode, and an optically compounded bend (OCB) mode.

When the display device of the present invention is a liquid crystal display device, the polarizing plate can be formed as a layer for transmitting only desired specific polarized light among light incident on the liquid crystal cell and light emitted from the liquid crystal cell. The polarizing plate can also be formed as part of a component for preventing reflection of external light.

The display device of the present invention may also be an organic electroluminescent display device. In this case, for example, the polarizing plate of the present invention is formed as part of a component for preventing reflection of external light.

Example

Hereinafter, an Example is shown and this invention is demonstrated concretely. However, this invention is not limited to the Example shown below, It can implement by changing arbitrarily in the range which does not deviate from the Claim of this invention, and its equal range.

In the following description, "%" and "part" indicating the amount are by weight unless otherwise indicated. In addition, the operation demonstrated below was performed on the conditions of normal temperature and normal pressure, unless otherwise stated.

[Assessment Methods]

(Measurement Method of Glass Transition Temperature of Resin)

Pellets of the measurement target resin were prepared, and the glass transition temperature of the resin pellets was measured using a differential scanning calorimeter ("DSC 6220" manufactured by Seiko Instruments Inc.). The conditions were 10 mg of sample weight and 20 degree-C / min of temperature increase rate.

(Measurement of phase difference and NZ coefficient)

Re and Rth were measured using the phase difference measuring apparatus (product name "Axoscan" by the Axometric company) at wavelength 590 nm, and NZ coefficient was calculated | required based on it.

(Measurement Method of Peel Force Pa Between Film (A) and Film (B))

The long multilayer film of the measurement object was cut out, and the slice of longitudinal direction x width direction = 300 mm x 50 mm was obtained. The slice was put into the tensile tester (type "5564" by Instron Co., Ltd.) with a constant temperature and humidity chamber, and it heated up at predetermined oven temperature Tov. The 180 degree peeling test was done in the state which maintained the said temperature. The 180 ° peeling test was carried out on the conditions of the tensile velocity of 300 mm / min by holding the film A with the chuck of one measuring apparatus, holding the film B with the other chuck. The average value of the measured value of peeling force Pa (N / 50mm) in stable tensile distance 50mm was employ | adopted as the value of peeling force Pa.

Production Example 1. Preparation of Film (A) -1

The pellet of resin (The resin of the norbornene polymer of glass transition temperature of 126 degreeC, brand name "Xeonoa", the Nippon Xeon Co., Ltd. product) containing an alicyclic structure containing polymer was dried at 100 degreeC for 5 hours. Then, the pellet of dried resin was supplied to the single screw extruder. After the resin was melted in an extruder, it was extruded in a sheet form onto a casting drum from a T die, through a polymer pipe and a polymer filter, and cooled. This obtained the elongate film (A) -1 of thickness 80micrometer, and width 1000mm. Manufactured film (A) -1 was wound up and collect | recovered in roll shape.

Production Example 2. Preparation of Film (A) -2]

The same operation as in Production Example 1 was carried out except that the area of the opening of the T die was changed. As a result, a long film (A) -2 having a thickness of 185 µm and a width of 1000 mm was obtained, wound up in a roll, and recovered.

Production Example 3. Production of Film (A) -3]

The same operation as in Production Example 1 was carried out except that the area of the opening of the T die was changed. Thereby, the elongate film (A) -3 of thickness 133 micrometers and width 1000mm was obtained, it wound up in roll shape, and it collect | recovered.

Production Example 4. Production of Film (A) -4

The film (A) -1 obtained in the manufacture example 1 was unwound from a roll, and the corona treatment was given to both surfaces of the film (A) -1. This obtained the film (A) -4. The obtained film (A) -4 was wound up and collect | recovered in the roll shape, making the corona treatment surface into the winding inner side.

Production Example 5. Production of Raw Material Film of Film (B)

The pellet of the polyester resin ("PET-G 6763" by the Eastman company) was dried at 120 degreeC for 5 hours. The dried pellets were fed to the extruder, melted in the extruder, extruded in a sheet form onto the casting drum from the T die, through a polymer pipe and a polymer filter at a resin temperature of 260 ° C., and cooled. This obtained the raw material film of thickness 60micrometer and width 1400mm.

Production Example 6. Preparation of Film (B) -1]

The raw material film obtained by the manufacture example 5 was continuously supplied to the tenter type lateral stretch apparatus. Using this lateral stretch machine, the raw material film was stretched in the width direction on the conditions of extending | stretching temperature 80 degreeC, and draw ratio twice. Both ends of the stretched film width direction were trimmed, and the corona treatment was further given to the surface on one side. This obtained the elongate film (B) -1 of 900 mm in width and 42 micrometers in thickness. This film (B) was wound up and collect | recovered in the shape of a roll with the corona treatment surface as the winding inside.

Production Example 7. Preparation of Multilayer Film (C) -1

The film (B) -1 obtained in the manufacture example 6 was unwound from the roll, and the adhesive layer (pressure-sensitive adhesive layer of Fujimori Industrial Co., Ltd. "Mastack series") was transferred to the corona-treated surface of the film (B) -1. Moreover, the film (B) -1 was bonded together by the usual method through the adhesive layer on both surfaces of the film (A) -1 obtained by the manufacture example 1. Thereby, the elongate multilayer film which has a laminated constitution of (film (B) -1) / (adhesive layer) / (film (A) -1) / (adhesive layer)) / (film (B) -1) (C) -1 was obtained. This multilayer film (C) -1 was wound up and collect | recovered in roll shape. The thickness of each layer was 42 micrometers / 25 micrometers / 80 micrometers / 25 micrometers / 42 micrometers.

Production Example 8. Production of Multilayer Film (C) -2

The film (B) -1 obtained in the manufacture example 6 was unwound from the roll, and the adhesive layer (pressure-sensitive adhesive layer of Fujimori Industrial Co., Ltd. "Mastack series") was transferred to the corona-treated surface of the film (B) -1. Moreover, the film (B) -1 was bonded together by the normal method through the adhesive layer on both surfaces of the film (A) -4 obtained by the manufacture example 4. Thereby, the elongate multilayer film which has the laminated constitution of (film (B) -1) / (adhesive layer) / (film (A) -4) / (adhesive layer) / (film (B) -1) C)-2 was obtained. This multilayer film (C) -2 was wound up and collect | recovered in roll shape. The thickness of each layer was 42 micrometers / 25 micrometers / 80 micrometers / 25 micrometers / 42 micrometers.

Production Example 9. Fabrication of Multilayer Film (C) -3]

As film (B) -2, the self-adhesive stretched polypropylene film ("FSA 010M # 30" by Futura Chemical Co., Ltd.) was prepared. The film (B) -2 was bonded to both surfaces of the film (A) -1 obtained by the manufacture example 1 by a conventional method. This obtained the long multilayer film (C) -3 which has a laminated constitution of (film (B) -2) / (film (A) -1) / (film (B) -2). This multilayer film (C) -3 was wound up and collect | recovered in roll shape. The thickness of each layer was 30 micrometers / 80 micrometers / 30 micrometers.

Production Example 10 Preparation of Multilayer Film (C) -4]

Except having used the film (A) -2 obtained by the manufacture example 2 instead of the film (A) -1, by the same operation as the manufacture example 9, it is (film (B) -2) / (film (A) -2) A long multilayer film (C) -4 having a layer structure of) / (film (B) -2) was obtained. This multilayer film (C) -4 was wound up and collect | recovered in roll shape. The thickness of each layer was 30 micrometers / 185 micrometers / 30 micrometers.

Production Example 11. Preparation of Multilayer Film (C) -5]

Except for using the film (A) -3 obtained in the manufacturing example 3 instead of the film (A) -1, by the same operation as the manufacturing example 9, it is (film (B) -2) / (film (A) -3) A long multilayer film (C) -5 having a layer structure of) / (film (B) -2) was obtained. This multilayer film (C) -5 was wound up and collect | recovered in roll shape. The thickness of each layer was 30 micrometers / 133 micrometers / 30 micrometers.

Production Example 12 Preparation of Multilayer Film (C) -6]

The film (B) -1 obtained in the manufacture example 6 was unwound from the roll, and the adhesive layer (pressure-sensitive adhesive layer of Fujimori Industrial Co., Ltd. "Mastack series") was transferred to the corona-treated surface of the film (B) -1. Moreover, the corona treatment was given to the surface of the adhesive layer which was transferred. On both surfaces of the film (A) -4 obtained in the manufacture example 4, the film (B) -1 which has a corona-treated adhesive layer was bonded together through the adhesive layer by a conventional method. Thereby, the elongate multilayer film which has the laminated constitution of (film (B) -1) / (adhesive layer) / (film (A) -4) / (adhesive layer) / (film (B) -1) C)-6 was obtained. This multilayer film (C) -6 was wound up and collect | recovered in roll shape. The thickness of each layer was 42 micrometers / 25 micrometers / 80 micrometers / 25 micrometers / 42 micrometers.

Example 1

Floating longitudinal drawing machine was prepared. This stretching machine is a stretching machine which can stretch the elongate film conveyed in the longitudinal direction in the oven by which temperature was adjusted. The multilayer film (C) -2 obtained in the manufacture example 8 was unwound from a roll, it was conveyed in the film longitudinal direction, and was supplied to the said longitudinal drawing machine. The multilayer film (C) -2 was conveyed in the oven of a longitudinal drawing machine. At the time of conveyance, the oven temperature Tov was 135 degreeC and it extended | stretched by the draw ratio 1.07 times.

Moreover, the peeling process was performed in the vicinity of the exit in oven. The peeling process was performed by pulling the film (B) -1 of both sides of multilayer film (C) -2, and peeling film (B) -1 continuously from film (A) -4. The direction of pulling two films (B) -1 was the direction perpendicular | vertical to the surface of the film (A) -4 to be conveyed, and also made it the direction opposite to each other. Thereby, peeling to which force was applied in the thickness direction of the film (A) -4 was performed, and the film (A) -4 was extended | stretched in the thickness direction. Peeling rate was 5 m / min. As a result, film direction stretched film (A) -4 was obtained as an optical film.

In-plane retardation Re, thickness, and NZ coefficient of the obtained optical film were measured. In addition, the peel force Pa between the film (A) and the film (B) in a multilayer film in Tov of this Example was measured. The results are shown in Table 1. As can be seen from the results in Table 1, the obtained optical film had a NZ coefficient between 0 and 1.

Example 2

The multilayer film (C) -3 obtained in the manufacture example 9 was unwound from a roll, it was conveyed in the film longitudinal direction, and was supplied to the same longitudinal stretcher as used in Example 1. The multilayer film (C) -3 was conveyed in the oven of a longitudinal drawing machine. At the time of conveyance, oven-temperature Tov was 126 degreeC. In addition, the draw ratio was 1.00 times, that is, conveyance which does not involve drawing was performed.

Moreover, the peeling process was performed in the vicinity of the exit in oven. The peeling process was performed by pulling the film (B) -2 of both sides of multilayer film (C) -3, and peeling film (B) -2 continuously from film (A) -1. The direction of pulling two films (B) -2 was the direction perpendicular | vertical to the surface of the film (A) -1 conveyed, and also made it the direction opposite to each other. Thereby, peeling to which force was applied in the thickness direction of the film (A) -1 was performed, and the film (A) -1 was extended | stretched in the thickness direction. Peeling rate was 1 m / min. As a result, the film (A) -1 stretched in the thickness direction was obtained as an optical film.

In-plane retardation Re, thickness, and NZ coefficient of the obtained optical film were measured. In addition, the peel force Pa between the film (A) and the film (B) in a multilayer film in Tov of this Example was measured. The results are shown in Table 1. As can be seen from the results in Table 1, the obtained optical film had a NZ coefficient between 0 and 1.

Example 3

The optical film was obtained and evaluated by the same operation as Example 2 except having changed the temperature Tov in oven from 126 degreeC to 130 degreeC, and extending | stretching by changing draw ratio from 1.00 times to 1.02 times. The peeling rate in the peeling process was 1 m / min. The results are shown in Table 1. As can be seen from the results in Table 1, the obtained optical film had a NZ coefficient between 0 and 1.

Example 4

The multilayer film (C) -4 obtained in the manufacture example 10 was unwound from a roll, it was conveyed in the film longitudinal direction, and was supplied to the same longitudinal stretcher as used in Example 1. The multilayer film (C) -4 was conveyed in the oven of a longitudinal drawing machine. At the time of conveyance, the oven temperature Tov was 135 degreeC and it extended | stretched by the draw ratio 1.07 times.

Moreover, the peeling process was performed in the vicinity of the exit in oven. The peeling process was performed by pulling the film (B) -2 of both sides of multilayer film (C) -4, and peeling film (B) -2 continuously from film (A) -2. The direction of pulling two films (B) -2 was the direction perpendicular | vertical to the surface of the film (A) -2 conveyed, and also made it the direction opposite to each other. Thereby, peeling to which force was applied in the thickness direction of the film (A) -2 was performed, and the film (A) -2 was extended | stretched in the thickness direction. Peeling rate was 1 m / min. As a result, film (A) -2 stretched in the thickness direction was obtained as an optical film.

In-plane retardation Re, thickness, and NZ coefficient of the obtained optical film were measured. In addition, the peel force Pa between the film (A) and the film (B) in a multilayer film in Tov of this Example was measured. The results are shown in Table 1. As can be seen from Table 1, the obtained optical film had a NZ coefficient between 0 and 1.

Example 5

The optical film was obtained and evaluated by the same operation as Example 2 except having changed the temperature Tov in oven from 126 degreeC to 135 degreeC, and extending | stretching and changing draw ratio from 1.00 time to 1.07 time. The peeling rate in the peeling process was 5 m / min. The results are shown in Table 1. As can be seen from the results in Table 1, the obtained optical film had a NZ coefficient between 0 and 1.

Example 6

The multilayer film (C) -5 obtained in the manufacture example 11 was unwound from a roll, it was conveyed in the film longitudinal direction, and was supplied to the same longitudinal stretcher as used in Example 1. The multilayer film (C) -5 was conveyed in the oven of a longitudinal drawing machine. At the time of conveyance, the oven temperature Tov was 140 degreeC and it extended | stretched by the draw ratio 1.07 times.

Moreover, the peeling process was performed in the vicinity of the exit in oven. The peeling process was performed by pulling the film (B) -2 of both sides of multilayer film (C) -5, and peeling film (B) -2 continuously from film (A) -3. The direction of pulling two films (B) -2 was the direction perpendicular | vertical to the surface of the film (A) -3 to be conveyed, and also made it the direction opposite to each other. Thereby, peeling to which force was applied in the thickness direction of the film (A) -3 was performed, and the film (A) -3 was extended in the thickness direction. Peeling rate was 1 m / min. As a result, film (A) -3 stretched in the thickness direction was obtained as an optical film.

In-plane retardation Re, thickness, and NZ coefficient of the obtained optical film were measured. In addition, the peel force Pa between the film (A) and the film (B) in a multilayer film in Tov of this Example was measured. The results are shown in Table 1. As can be seen from the results in Table 1, the obtained optical film had a NZ coefficient between 0 and 1.

Comparative Example 1

The multilayer film (C) -1 obtained in the manufacture example 7 was unwound from a roll, it was conveyed in the film longitudinal direction, and was supplied to the same longitudinal stretcher as used in Example 1. The multilayer film (C) -1 was conveyed in the oven of a longitudinal drawing machine. At the time of conveyance, the oven temperature Tov was 135 degreeC and it extended | stretched by the draw ratio 1.07 times.

Moreover, although the peeling process was tried in the vicinity of the exit in oven, peeling of the film (B) -1 occurs in the multilayer film (C) -1 which reached the exit in the oven, and film (A)- Wrinkles generate | occur | produced in the whole surface of 1, and the peeling process was not able to be performed.

In addition, the peel force Pa between the film (A) and the film (B) in a multilayer film in Tov of this Example was measured. The results are shown in Table 1.

Comparative Example 2

The multilayer film (C) -6 obtained in the manufacture example 12 was unwound from a roll, it conveyed in the film longitudinal direction, and was supplied to the same longitudinal stretcher as used in Example 1. The multilayer film (C) -6 was conveyed in the oven of a longitudinal drawing machine. At the time of conveyance, the oven temperature Tov was 135 degreeC and it extended | stretched by the draw ratio 1.07 times.

Moreover, although the peeling process was tried in the vicinity of the exit inside oven, peeling at the interface of a film (A) and an adhesive layer is not performed smoothly, but an adhesive remains on the surface of the film (A) after peeling. The manufacture of the favorable optical film was not able to be performed.

In addition, the peel force Pa between the film (A) and the film (B) in a multilayer film in Tov of this Example was measured. The results are shown in Table 1.

Comparative Example 3

An optical film was obtained and evaluated by the same operation as Example 2 except having changed the temperature Tov in oven from 126 degreeC to 120 degreeC. The peeling rate in the peeling process was 5 m / min. The results are shown in Table 1. As can be seen from the results in Table 1, the obtained optical film had a value of NZ coefficient of 1.6 and higher than 1.

In addition, the peel force Pa between the film (A) and the film (B) in a multilayer film in Tov of this Example was measured. The results are shown in Table 1.

The result of an Example and a comparative example is put together in Table 1, and is shown.

The meaning of the abbreviation in a table | surface is as follows.

COP: Resin containing an alicyclic structure containing polymer (resin of the norbornene polymer of glass transition temperature of 126 degreeC, brand name "Zenooa", the Nippon Xeon Corporation make).

PET: Polyester resin ("PET-G 6763" by Eastman).

OPP: Self-adhesive stretched polypropylene film ("FSA 010M # 30" by Futamura Chemical Corporation).

As can be seen from the results in Table 1, in the present examples where the relationship between Tov and TgA and the value of Pa meets the requirements of the present application, an optical film of 0 <Nz <1 can be easily produced. Can be.

100: multilayer film
111: film (B)
112: film (B)
121: adhesive layer
122: pressure-sensitive adhesive layer
131: film (A)
132: optical film
151: nip roll upstream of the peeling region
152: nip roll upstream of the peeling region
161: nip roll downstream of peeling area
162: nip roll downstream of the peeling area
200: multilayer film
231 film (A)
211: film (B)
221: adhesive layer
232: optical film
P: peeling area

Claims (5)

Including peeling process which provides multilayer film to peeling process,
The said multilayer film is a multilayer film containing the film (A) which consists of thermoplastic resin A, and the film (B) formed in the one or both surfaces of the said film (A),
The peeling treatment includes peeling the film (B) from the film (A) at a temperature Tov (° C.) so that a force is applied in the thickness direction of the film (A),
The temperature Tov and the glass transition temperature TgA (° C.) of the film A satisfy a relationship of Tov ≧ TgA,
In the said multilayer film, peeling force Pa of the said film (A) and the said film (B) in temperature Tov is 0.03 N / 50 mm or more and 0.5 N / 50 mm or less,
Method for producing an optical film.
The method of claim 1,
The said thermoplastic resin A is a manufacturing method of the optical film containing an alicyclic structure containing polymer.
The method according to claim 1 or 2,
The manufacturing method of the optical film further including the extending process of extending | stretching the said multilayer film to the in-plane direction.
The polarizing plate provided with the optical film and polarizer manufactured by the manufacturing method in any one of Claims 1-3.
The display apparatus provided with the optical film manufactured by the manufacturing method in any one of Claims 1-3.

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