JP2017177596A - Method for producing optical film, and optical film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing an optical film which can achieve suppression in occurrence of a defect caused by blocking such as scratches and unevenness caused by contact between films and suppression in occurrence of winding deviation caused by meander of the film, and to provide an optical film produced by the production method.SOLUTION: A film is formed by coextrusion of a first thermoplastic resin composition containing particles which impart lubricity to a film such as multilayer-structured particles having a rubber portion having a degree of crosslinking of 2.3 wt.% or more and 4.0 wt.% or less and a particle size of 180 nm or more and 400 nm or less, and a second thermoplastic resin composition containing little particles that impart lubricity thereto.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an optical film manufacturing method and an optical film.

Optical transparency, optical homogeneity, and smoothness are required for an optical film typified by a polarizer protective film for protecting a polarizer and a film substrate for a liquid crystal display device. .
As a method for producing such an optical film, a melt extrusion method is known in which a resin composition as a film raw material is melted with an extruder and extruded from a die to form a film.
When the film thus obtained is used as a product, the film is wound into a roll. However, there is a problem (hereinafter referred to as a blocking-induced defect) in which the film comes into contact with each other inside the wound roll to cause scratches or uneven defects in the film.

  As a method for suppressing this blocking-induced defect, for example, a method of improving film slipperiness by adding antiblocking slippery particles such as silica particles having a specific particle diameter to a molten resin is known. (See Patent Document 1).

Japanese Patent No. 5587209

However, when slipping particles are added to the molten resin as in the method described in Patent Document 1, an effect of preventing blocking is obtained, but there is a problem that film quality such as transparency is deteriorated.
Further, in the film manufacturing process, the entire width of the entire film becomes slippery, so that the film is easy to meander without being gripped by the transport roll during film transport. When the film meanders, the problem of winding deviation tends to occur.
Winding misalignment is a problem related to the nonuniformity of the roll end face position caused by the shift of the end position when the film is wound into a roll.

  In view of the above situation, the present invention can achieve both suppression of the occurrence of blocking-induced defects such as scratches and irregularities caused by contact between films and the like, and suppression of the occurrence of winding deviation due to meandering of the film. It aims at providing the manufacturing method of a film, and the optical film which can be manufactured with the said manufacturing method.

  As a result of intensive studies by the inventor in order to solve the above-mentioned problems, the multilayer structure particles having a rubber part having a degree of crosslinking of 2.3% by weight to 4.0% by weight and a particle diameter of 180 nm to 400 nm. A film obtained by co-extrusion of a first thermoplastic resin composition containing particles imparting lubricity to such a film and a second thermoplastic resin composition containing no or few particles imparting lubricity It was found that the above-mentioned problems can be solved by forming the film, and the present invention has been achieved.

That is, the present invention
(I) A first thermoplastic resin composition containing multilayer structured particles having a rubber part having a degree of crosslinking of 2.3 wt% or more and 4.0 wt% or less and a particle diameter of 180 nm or more and 400 nm or less is used as a die exit. From the central part in the width direction, a second thermoplastic resin composition containing no multilayer structure particles or containing a lower amount than the first thermoplastic resin composition is coextruded from both end parts in the width direction of the die exit, Manufacturing method of optical film to be molded into
(Ii) The method according to (i), wherein the second thermoplastic resin composition contains rubber particles other than the multilayer structure particles,
(Iii) a first thermoplastic resin composition containing slipping particles and a second thermoplastic resin composition containing no slipping particles or containing a lower amount than the first thermoplastic resin composition at the die outlet; A method for producing an optical film, which is co-extruded from different locations in the width direction and formed into a film.
(Iv) The method according to (iii), wherein the second thermoplastic resin composition is extruded from two or more parts with respect to the width direction of the die outlet.
(V) Extruding the second thermoplastic resin composition from both ends of the die outlet (iv),
(Vi) The first thermoplastic resin composition contains an acrylic resin and the method according to any one of (i) to (v),
(Vii) The second thermoplastic resin composition contains an acrylic resin (i) to the method according to any one of (vi),
(Viii) an optical film containing a thermoplastic resin,
Regarding the width direction of the optical film,
The central part is a first region including multilayer structure particles having a rubber part having a degree of crosslinking of 2.3% to 4.0% and a particle diameter of 180 nm to 400 nm,
Both end portions are second regions that do not include multi-layer structured particles or that are included in a lower amount than the first region,
(Ix) an optical film containing a thermoplastic resin,
Regarding the width direction of the optical film,
A first region containing lubricious particles;
An optical film having a second region that does not contain lubricious particles or in a lower amount than the first region,
(X) the second region includes two or more regions with respect to the width direction of the optical film, and (xi) the second region includes both end portions with respect to the width direction of the optical film (x ) Optical film,
I will provide a.

  According to the present invention, the production of an optical film capable of satisfying both the suppression of the occurrence of blocking-induced defects such as the occurrence of scratches and irregularities caused by the contact between films and the suppression of the occurrence of winding deviation due to the meandering of the film. A method and an optical film that can be produced by the production method can be provided.

It is a figure which shows typically about pinching molding.

≪First manufacturing method≫
Hereinafter, the first thermoplastic resin composition including multilayer structure particles having a rubber part having a degree of crosslinking of 2.3 wt% or more and 4.0 wt% or less and a particle diameter of 180 nm or more and 400 nm or less is used as the width of the die exit. A second thermoplastic resin composition containing no multilayer structure particles or containing a lower amount than the first thermoplastic resin composition is co-extruded from both ends of the width direction of the die exit from the central portion with respect to the direction to form a film About the manufacturing method of the optical film to shape | mold, it describes as a 1st manufacturing method.

<Film forming>
First, film forming by coextrusion will be described below.
FIG. 1 is a diagram schematically showing sandwiching molding in a method for producing an optical film. In FIG. 1, the co-extruder 10 is simplified and only the vicinity of the T die 11 is illustrated.
First, a predetermined first thermoplastic resin composition and a second thermoplastic resin composition as film raw materials are charged into the co-extruder 10 and heated to a temperature equal to or higher than the glass transition temperature in the co-extruder 10. It will be in a molten state.

  The molten first thermoplastic resin composition and the second thermoplastic resin composition are transferred to the T die 11 attached to the outlet side of the co-extruder 10, and at the die outlet 12 at the tip of the die, respectively. The liquid is discharged in a molten state from a predetermined position in the width direction. The molten thermoplastic resin composition 13 takes a sheet shape due to the shape of the die outlet 12 at the time of discharge.

Here, the first thermoplastic resin composition is discharged from the center of the die outlet 12 in the width direction.
And since the 1st thermoplastic resin composition contains the multilayer structure particle | grains which satisfy | fill said predetermined requirements, in the film obtained, the area | region which consists of a 1st thermoplastic resin composition has lubricity.
For this reason, when the first thermoplastic resin composition is discharged from the central portion in the width direction of the die outlet 12, slipperiness is imparted to the central region of the film, and scratches caused by contact between the films or between the film and the roll Occurrence of irregularities (blocking defects) is suppressed.

On the other hand, the second thermoplastic resin composition is discharged from both ends of the die outlet 12 in the width direction.
And the 2nd thermoplastic resin composition does not contain said multilayer structure particle, or contains only a small amount of multilayer structure particles rather than a 1st thermoplastic resin composition.
For this reason, when the second thermoplastic resin composition is discharged from both ends of the die outlet 12 in the width direction, the slipping of the regions at both ends of the film is poor, and as a result, the film is firmly gripped by the transport roll during film transport. Cheap. For this reason, the meandering of the film is also suppressed, and thereby the occurrence of wrinkles and scratches on the film and the problem of winding misalignment hardly occur.

Here, the width | variety of the both ends of the width direction of the die exit 12 is not specifically limited in the range which does not inhibit the objective of this invention. The width of both end portions is preferably 20 mm or more, more preferably 30 mm or more from both extreme ends of the die outlet 12.
Moreover, it is preferable that the total width of both ends is in a range of 15% or less with respect to the total width of the die.
The preferable value of the upper limit of the width at both ends varies depending on the total width of the film. Typically, the width at both ends is preferably 150 mm or less, more preferably 100 mm or less from both extreme ends of the die outlet 12.

If the width of both ends is too narrow, the area of the low slip portion at both ends of the film is narrow, and it may be difficult to suppress the meandering of the film.
Moreover, since the film of the position set as this die both ends differs from a center part in lubricity and film physical property, it may not be contained in the product for which high quality is calculated | required. In this case, it is preferable that the film corresponding to both ends is slit and not included in the final product. Therefore, if both ends of the die are more than 15%, the loss at both ends increases and the yield in the width direction decreases, which is not preferable.
However, the product may include both end portions as long as the difference in slipperiness and film physical properties between the center portion and both end portions is within an allowable range required for the product.

As a co-extrusion method, a main extruder that melts the first thermoplastic resin composition and extrudes it at the center of the die outlet 12, and an end that melts and extrudes the second thermoplastic resin composition at both ends of the die outlet 12 A method of discharging the first thermoplastic resin composition and the second thermoplastic resin composition from a predetermined position of the die outlet 12 using a part extruder, respectively.
About the edge part extrusion machine extruded to die | dye both ends, both ends may be covered by 1 unit | set, and may be covered by 2 units | sets per side. The plurality of extruders may be introduced into the T die 11 by a feed block method or the like.

In addition, in the range which does not inhibit the objective of this invention, it differs from a 1st thermoplastic resin composition and a 2nd thermoplastic resin composition from the area | region between the both ends of the die exit 12, and the center part of the die exit 12. The thermoplastic resin composition may be coextruded.
However, it is preferable that only the first thermoplastic resin composition and the second thermoplastic resin composition are extruded from the die outlet 12 from the viewpoint that there is little variation in physical properties in the width direction of the obtained film.

The sheet-like thermoplastic resin composition 13 in the molten state is smoothed by being sandwiched between a pair of smoothing rolls. One of the smoothing rolls is an elastic roll 14 and the other is a cast roll 15. The elastic roll 14 is a roll in which the surface of a roll made of an elastic body such as rubber is covered with a metal film, and the roll surface is flattened by the metal film on the surface and functions as a smoothing roll.
The cast roll 15 is a hard roll made of metal.

The sheet-like thermoplastic resin composition 13 discharged from the die outlet 12 is sandwiched between the elastic roll 14 and the cast roll 15 so as to be cooled to a temperature equal to or lower than the glass transition temperature, thereby improving the smoothness of the sheet surface. .
In addition, the said pinching shaping | molding process is a process for smoothing the film surface, and is different from the process for extending | stretching a film.
FIG. 1 is a schematic view of the sheet-like thermoplastic resin composition 13 as seen from a plane perpendicular to the width direction of the die outlet 12.

  As described above, the optical film stretched in the longitudinal direction is continuously obtained by continuously performing the discharge from the co-extrusion machine 10 (die outlet 12) and the sandwiching process by the elastic roll 14 and the cast roll 15. To be manufactured.

  Moreover, the 1st manufacturing method may include the process of inspecting the foreign material in a film, and the process of extending | stretching as needed.

The thickness of the optical film manufactured according to the said method is not specifically limited.
In the first manufacturing method, for example, even in a very thin film having a thickness of 30 μm or more and 80 μm or less, slipping suppression at both ends can be realized, and slipping can be imparted to the central portion, so that contact between the films, etc. It is possible to achieve both suppression of the occurrence of defects caused by blocking, such as generation of scratches and irregularities, and suppression of generation of wrinkles and scratches on the film due to meandering of the film and occurrence of winding deviation.
In the conventional method, during the production of thin films, the occurrence of blocking-induced defects such as scratches and unevenness caused by contact between films, etc., and the occurrence of wrinkles and scratches on the film due to film meandering, Therefore, it is difficult to achieve both suppression of winding deviation and this effect is remarkable.

<First thermoplastic resin composition>
In the first manufacturing method, co-extrusion is performed. In the co-extrusion, at least the first thermoplastic resin composition and the second thermoplastic resin composition are used.
The first thermoplastic resin composition includes a multilayer resin particle having a rubber part having a degree of cross-linking of 2.3% by weight to 4.0% by weight and a particle diameter of 180 nm to 400 nm. It is a thing.
Hereinafter, essential or optional components contained in the first thermoplastic resin composition will be described.

(Thermoplastic resin)
A thermoplastic resin is a material which comprises the matrix part in a film. The thermoplastic resin used for the production of the film is not particularly limited as long as it is a thermoplastic resin that can be used as an optical film and can be molded by melt extrusion.
For example, polycarbonate resin, aromatic vinyl resin and hydrogenated product thereof, polyolefin resin, acrylic resin, polyester resin, polyarylate resin, polyimide resin, polyethersulfone resin, polyamide resin, cellulose resin, A thermoplastic resin composition such as polyphenylene oxide resin may be used. Among these, acrylic resins are particularly preferable from the viewpoint of transparency.

  Although it does not restrict | limit especially as acrylic resin, The methacryl resin which used methyl methacrylate as a monomer component can be used, and what contained 30-100 weight% of structural units derived from methyl methacrylate is preferable. Among acrylic resins, heat-resistant acrylic resins are preferable.

Examples of heat resistant acrylic resins include:
1) an acrylic resin in which an N-substituted maleimide compound is copolymerized as a copolymerization component;
2) Glutaric anhydride acrylic resin,
3) an acrylic resin having a lactone ring structure,
4) Glutarimide acrylic resin,
5) an acrylic resin containing a hydroxyl group and / or a carboxyl group,
6) Aromatic vinyl-containing acrylic polymer obtained by polymerizing aromatic vinyl monomer and other monomer copolymerizable therewith (for example, styrene monomer and other monomer copolymerizable therewith) Styrene-containing acrylic polymer obtained by polymerizing the polymer)
7) A hydrogenated aromatic vinyl-containing acrylic polymer obtained by partially or fully hydrogenating the aromatic ring of the resin of 6) above (for example, a styrene monomer and other monomers copolymerizable therewith) A partially hydrogenated styrene-containing acrylic polymer obtained by partially hydrogenating the aromatic ring of a styrene-containing acrylic polymer obtained by polymerizing the polymer),
8) An acrylic polymer containing a cyclic acid anhydride repeating unit can be used.
From the viewpoints of heat resistance and optical properties, a glutarimide acrylic resin can be more preferably used.

（式中、Ｒ^１およびＲ^２は、それぞれ独立して、水素原子または炭素数１〜８のアルキル基であり、Ｒ^３は、炭素数１〜１８のアルキル基、炭素数３〜１２のシクロアルキル基、または炭素数５〜１５の芳香環を含む置換基である。）
で表される単位（以下、「グルタルイミド単位」ともいう）と、
下記一般式（２）：

（式中、Ｒ^４およびＲ^５は、それぞれ独立して、水素原子または炭素数１〜８のアルキル基であり、Ｒ^６は、炭素数１〜１８のアルキル基、炭素数３〜１２のシクロアルキル基、または炭素数５〜１５の芳香環を含む置換基である。）
で表される単位（以下、「（メタ）アクリル酸エステル単位」ともいう）とを含むグルタルイミドアクリル系樹脂を好適に用いることができる。 The glutarimide acrylic resin will be described in detail below. Specific examples of the glutarimide acrylic resin include the following general formula (1):

(Wherein R ¹ and R ² are each independently a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and R ³ is an alkyl group having 1 to 18 carbon atoms or a cyclohexane having 3 to 12 carbon atoms. An alkyl group or a substituent containing an aromatic ring having 5 to 15 carbon atoms.)
(Hereinafter also referred to as “glutarimide unit”),
The following general formula (2):

(In the formula, R ⁴ and R ⁵ each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and R ⁶ represents an alkyl group having 1 to 18 carbon atoms or a cyclohexane having 3 to 12 carbon atoms. An alkyl group or a substituent containing an aromatic ring having 5 to 15 carbon atoms.)
A glutarimide acrylic resin containing a unit represented by (hereinafter also referred to as “(meth) acrylic acid ester unit”) can be suitably used.

（式中、Ｒ^７は、水素原子または炭素数１〜８のアルキル基であり、Ｒ^８は、炭素数６〜１０のアリール基である。）
で表される単位（以下、「芳香族ビニル単位」ともいう）をさらに含んでいてもよい。 Moreover, the said glutarimide acrylic resin is the following general formula (3) as needed.

(In the formula, R ⁷ is a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and R ⁸ is an aryl group having 6 to 10 carbon atoms.)
(Hereinafter also referred to as “aromatic vinyl unit”).

In the general formula (1), R ¹ and R ² are each independently a hydrogen atom or a methyl group. R ³ is preferably a hydrogen atom, a methyl group, a butyl group, or a cyclohexyl group, R ¹ is a methyl group, R ² is a hydrogen atom, and R ³ is more preferably a methyl group.

The glutarimide acrylic resin may include only a single type as a glutarimide unit, or may include a plurality of types in which R ¹ , R ² , and R ³ in the general formula (1) are different. May be.
When the (meth) acrylate unit represented by the general formula (2) is continuous, the glutarimide unit includes two adjacent alkoxycarbonyl groups contained in the continuous (meth) acrylate unit. It can be formed by imidizing (carboxylic acid ester group).

  In addition, acid anhydrides such as maleic anhydride, or half esters of such acid anhydrides and linear or branched alcohols having 1 to 20 carbon atoms; acrylic acid, methacrylic acid, maleic acid, maleic anhydride, The glutarimide unit can also be formed by imidizing an α, β-ethylenically unsaturated carboxylic acid such as itaconic acid, itaconic anhydride, crotonic acid, fumaric acid or citraconic acid.

In the above general formula (2), R ⁴ and R ⁵ are each independently hydrogen or a methyl group, R ⁶ is preferably hydrogen or a methyl group, R ⁴ is hydrogen, and R ⁵ is More preferably, it is a methyl group, and R ⁶ is more preferably a methyl group.
The glutarimide acrylic resin may contain only a single type as a (meth) acrylic acid ester unit, or a plurality of different R ^{4 s} , R ^{5 s} , and R ^{6 s} in the general formula (2). The type may be included.
The glutarimide acrylic resin preferably contains styrene, α-methylstyrene or the like as the aromatic vinyl constituent unit represented by the general formula (3), and more preferably contains styrene.
Moreover, the said glutarimide acrylic resin may contain only a single kind as an aromatic vinyl structural unit, and may contain the some kind from which R < ⁷ > and R < ⁸ > differ.

In the above general formula (2), R ⁴ and R ⁵ are each independently a hydrogen atom or a methyl group, R ⁶ is preferably a hydrogen atom or a methyl group, R ⁴ is a hydrogen atom, More preferably, R ⁵ is a methyl group and R ⁶ is a methyl group.
The glutarimide acrylic resin may contain only a single type as a (meth) acrylic acid ester unit, or a plurality of different R ^{4 s} , R ^{5 s} , and R ^{6 s} in the general formula (2). The type may be included.
The glutarimide acrylic resin preferably contains styrene, α-methylstyrene or the like as the aromatic vinyl constituent unit represented by the general formula (3), and more preferably contains styrene.
Moreover, the said glutarimide acrylic resin may contain only a single kind as an aromatic vinyl structural unit, and may contain the some kind from which R < ⁷ > and R < ⁸ > differ.

In the glutarimide acrylic resin, the content of the glutarimide unit represented by the general formula (1) is not particularly limited, and is preferably changed depending on, for example, the structure of R ³ .

Generally, the content of the glutarimide unit is preferably 1% by weight or more of the glutarimide acrylic resin, more preferably 1% by weight to 95% by weight, still more preferably 2% by weight to 90% by weight. A weight percent to 80 weight percent is particularly preferred.
If the content of the glutarimide unit is within the above range, the heat resistance and transparency of the resulting glutarimide acrylic resin may decrease, or the moldability and mechanical strength when processed into a film may decrease. Hard to do.

  On the other hand, when the content of the glutarimide unit is less than the above range, the resulting glutarimide acrylic resin tends to be insufficient in heat resistance or impaired in transparency. On the other hand, if the amount is larger than the above range, the heat resistance and melt viscosity are unnecessarily increased, the molding processability is deteriorated, the mechanical strength during film processing becomes extremely brittle, or the transparency is impaired. Tend.

In the glutarimide acrylic resin, the content of the aromatic vinyl unit represented by the general formula (3) is not particularly limited, and can be appropriately set according to required physical properties. Depending on the application used, the content of the aromatic vinyl unit represented by the general formula (3) may be 0% by weight.
When the aromatic vinyl unit represented by the general formula (3) is included, the content is preferably 10% by weight or more based on the total repeating unit of the glutarimide acrylic resin, and preferably 10% by weight to 40%. More preferably, it is more preferably 15 wt% to 30 wt%, and particularly preferably 15 wt% to 25 wt%. If the content of the aromatic vinyl unit is within the above range, the resulting glutarimide acrylic resin is unlikely to have insufficient heat resistance and mechanical strength during film processing is unlikely to decrease.
On the other hand, when the content of the aromatic vinyl unit is larger than the above range, the resulting glutarimide acrylic resin tends to be insufficient in heat resistance.

The glutarimide acrylic resin may be further copolymerized with other units other than the glutarimide unit, the (meth) acrylic acid ester unit, and the aromatic vinyl unit, if necessary.
As other units, for example, nitrile monomers such as acrylonitrile and methacrylonitrile, and maleimide monomers such as maleimide, N-methylmaleimide, N-phenylmaleimide, and N-cyclohexylmaleimide are copolymerized. A structural unit can be mentioned.
These other units may be directly copolymerized or graft copolymerized in the glutarimide acrylic resin.

The weight average molecular weight of the glutarimide acrylic resin is not particularly limited, but is preferably 1 × 10 ^{4 to} 5 × 10 ⁵ . If it is in the said range, a moldability will fall and it will be hard to lack the mechanical strength at the time of film processing. On the other hand, when the weight average molecular weight is smaller than the above range, the mechanical strength when formed into a film tends to be insufficient. Moreover, when larger than the said range, the viscosity at the time of melt-extrusion is high, there exists a tendency for the moldability to fall and for the productivity of a molded article to fall.

  The glass transition temperature of the glutarimide acrylic resin is not particularly limited, but is preferably 110 ° C. or higher, and more preferably 120 ° C. or higher. When the glass transition temperature is within the above range, the applicable range of the obtained thermoplastic resin composition can be expanded.

  Although the manufacturing method of the said glutarimide acrylic resin is not restrict | limited in particular, For example, the method etc. which are described in Unexamined-Japanese-Patent No. 2008-273140 are mention | raise | lifted.

(Multilayer structure particles with rubber part)
The first thermoplastic resin composition includes multi-layer structured particles having a rubber part having a degree of cross-linking of 2.3% by weight to 4.0% by weight and a particle diameter of 180 nm to 400 nm. Such multilayer structured particles increase the slipperiness of the film and impart anti-blocking properties to the film, and are excellent in dispersibility within the film, and are difficult to reduce the transparency of the film.

The multilayer structure particle includes a rubber portion having a degree of cross-linking of 2.3 wt% or more and 4.0 wt% or less. For this reason, the multilayer structure particles have a certain degree of hardness. As a result, when the film containing multilayer structure particles comes into contact with each other or between the film and the roll, the multilayer structure particles are hardly deformed, and the film is provided with lubricity.
The degree of cross-linking is the ratio of the weight of the bifunctional or higher polyfunctional monomer to the total weight of the monomers used for producing the rubber part material (% by weight). It is.

When the degree of crosslinking of the rubber part is less than 2.3% by weight, since the rubber part is flexible, the multilayer structure particles protruding from the film surface are easily deformed when coming into contact with the roll or film. For this reason, it is difficult to give the film desired lubricity.
When the degree of cross-linking of the rubber part exceeds 4.0% by weight, the multilayer structure particles are likely to be cracked or chipped, and the desired lubricity cannot be imparted to the central part of the film, or fine powder is produced during film production. There is a case.

  Furthermore, the particle diameter of the rubber part is 180 nm or more and 400 nm or less. By using multi-layer structured particles including a rubber part having such a size, it is easy to impart lubricity to the film without impairing the transparency of the film. When the particle diameter of the rubber part is less than 180 nm, it is difficult to impart the desired degree of lubricity to the film. Moreover, when the particle diameter of a rubber part is more than 400 nm, it is difficult to obtain a film having a desired degree of transparency. Here, the particle diameter of the rubber portion is determined by light scattering at a wavelength of 546 nm using a U-5100 type ratio beam spectrophotometer manufactured by Hitachi High-Technologies Corporation.

Since the first thermoplastic resin composition containing the thermoplastic resin described above and the multilayer structure particles described above is extruded from the central portion in the width direction of the die exit, the vicinity of the central portion in the width direction of the obtained optical film is This is an area with excellent lubricity.
For this reason, in the 1st manufacturing method, generation | occurrence | production of the damage | wound and uneven | corrugated defect (blocking origin defect) resulting from contact between films or a film and a roll is suppressed.

  The multilayer structured particle is composed of a core particle having a rubber part having the above-mentioned predetermined requirements and a shell layer. The shell layer may be a single layer or a multilayer.

The shell layer may be chemically bonded to the rubber part by a covalent bond or the like, and may cover the rubber part without being chemically bonded to the rubber part. When the shell layer has a multilayer structure of two or more layers, the layers constituting the shell layer may be chemically bonded to each other by a covalent bond or the like, or may not be chemically bonded. .
A preferred example of a method of chemically bonding the shell layer to the surface of the rubber part or the surface of another shell layer is a method of forming the shell layer by graft polymerization. Due to the presence of the shell layer, the compatibility with the thermoplastic resin to be mixed is improved, and the particles can be uniformly dispersed. When particles having no shell layer are mixed with a thermoplastic resin, the particles are difficult to uniformly disperse, and the transparency of the film may be lowered.

  Examples of the material for the rubber part include butadiene-based crosslinked polymers, (meth) acrylic crosslinked polymers, and organosiloxane-based crosslinked polymers. Among these, in terms of weather resistance (light resistance) and transparency of the film, a (meth) acrylic crosslinked polymer (in the present specification, a rubber part made of a (meth) acrylic copolymer is used as an acrylic rubber particle). Is also particularly preferred.

Examples of the acrylic rubber particles include ABS resin rubber particles, ASA resin rubber particles, and acrylic ester rubber particles.
As the multilayer structure particles, core shell particles obtained by forming a shell layer by performing graft polymerization using a desired monomer on the surface of these acrylic rubber particles are preferable.
From the viewpoint of transparency of the obtained film, the multilayer structure particles are preferably acrylic graft copolymer particles obtained by graft polymerization on the surface of the acrylic ester rubber-like polymer particles shown below. .
Acrylic graft copolymer particles can be obtained by polymerizing a monomer mixture containing methacrylic acid ester as a main component in the presence of acrylic ester rubber-like polymer particles.

An acrylic ester rubber-like polymer, which is a material of the rubber part, is a rubber-like polymer mainly composed of an acrylic ester. Specifically, a monomer mixture (100% by weight) composed of 50 to 100% by weight of an acrylic ester and 50 to 0% by weight of another copolymerizable vinyl monomer, and two or more per molecule Those obtained by polymerizing a polyfunctional monomer having a non-conjugated reactive double bond are preferred.
The polyfunctional monomer is used in a desired amount so that the degree of cross-linking of the rubber part is in the range of 2.3 wt% to 4.0 wt%.
All the monomers may be mixed and used, or may be used in two or more stages by changing the monomer composition.

As the acrylic ester, an alkyl group having 1 to 12 carbon atoms is preferably used from the viewpoint of polymerizability and cost. For example, methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, sec-butyl acrylate, isobutyl acrylate, benzyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, n-acrylate Examples include octyl, phenyl acrylate, and 2-phenoxyethyl acrylate.
Two or more of these acrylic esters may be used in combination.
The amount of the acrylate ester is preferably 50% by weight or more and 100% by weight or less, more preferably 60% by weight or more and 99% by weight or less, and further preferably 70% by weight or more and 99% by weight or less, in 100% by weight of the monomer mixture. Most preferably, it is at least 99% by weight.
If it is less than 50% by weight, the impact resistance is lowered, the elongation at the time of tensile rupture is lowered, and cracks tend to be generated when the film is cut.

  As other vinyl monomers copolymerizable with acrylic acid esters, methacrylic acid esters are particularly preferred from the viewpoint of weather resistance and transparency. Examples of the methacrylic acid esters include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, sec-butyl methacrylate, isobutyl methacrylate, benzyl methacrylate, cyclohexyl methacrylate, 2-methacrylic acid 2- Examples include phenoxyethyl, 2-ethylhexyl methacrylate, phenyl methacrylate, and n-octyl methacrylate.

  Aromatic vinyls and derivatives thereof, and vinyl cyanides are also preferred. Examples of these vinyl monomers include styrene, methylstyrene, acrylonitrile, methacrylonitrile and the like. Other examples include unsubstituted and / or substituted maleic anhydrides, (meth) acrylamides, vinyl esters, vinylidene halides, (meth) acrylic acid and salts thereof, and (hydroxyalkyl) acrylate esters.

  Examples of the polyfunctional monomer copolymerized with a monofunctional monomer mainly composed of an acrylate ester include allyl methacrylate, allyl acrylate, triallyl cyanurate, triallyl isocyanurate, diallyl phthalate, Uses diallyl malate, divinyl adipate, divinyl benzene, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetramethacrylate, dipropylene glycol dimethacrylate, and acrylates thereof can do. Two or more of these polyfunctional monomers may be used.

The multilayer structure polymer may further have another polymer layer on the inner side (center side) of the rubber part. From the viewpoint of antiblocking properties, a monomer mixture comprising 40 to 100% by weight of an alkyl methacrylate and 60 to 0% by weight of another monomer having a double bond copolymerizable therewith, and It is preferable to have a methacrylic crosslinked polymer layer obtained by polymerizing 0.01 to 10 parts by weight of a polyfunctional monomer with respect to 100 parts by weight of the monomer mixture. Examples of the monomer having a copolymerizable double bond include the above-mentioned other copolymerizable vinyl monomers, acrylic acid esters, and the like.
The acrylic graft copolymer comprising a rubber part and a shell layer formed on the surface of the rubber part by graft polymerization is 5 to 90 parts by weight (more preferably 5 parts by weight) of acrylic ester rubbery polymer particles. (~ 75 parts by weight) is preferably obtained by polymerizing 95 to 25 parts by weight of a monomer mixture mainly composed of methacrylic acid ester in at least one stage.

The methacrylic acid ester in the graft copolymer composition (monomer mixture) is preferably 50% by weight or more. If it is less than 50% by weight, the hardness and rigidity of the resulting film tend to decrease.
As monomers used for graft copolymerization, the above-mentioned methacrylic acid esters, acrylic acid esters, and vinyl monomers copolymerizable with these can be used in the same manner, and methacrylic acid esters and acrylic acid esters are preferably used. Is done. Methyl methacrylate, methyl acrylate, ethyl acrylate, and n-butyl acrylate are preferred from the viewpoint of suppressing compatibility with acrylic resins from the viewpoint of suppressing methylation of zipper depolymerization.

  From the viewpoint of optical isotropy, a (meth) acrylic monomer having an alicyclic structure, a heterocyclic structure or an aromatic group (referred to as a “ring structure-containing (meth) acrylic monomer”). ) Is also preferred as a monomer for graft copolymerization. Specific examples include benzyl (meth) acrylate, dicyclopentanyl (meth) acrylate, and 2-phenoxyethyl (meth) acrylate.

  The amount used is 100% by weight of the total amount of the monomer mixture for graft copolymerization (total amount of the ring structure-containing (meth) acrylic monomer and other monofunctional monomers copolymerizable therewith). It is preferably 1 to 100% by weight, more preferably 5 to 70% by weight, and most preferably 5 to 50% by weight.

  Examples of the other monofunctional monomers that can be copolymerized with the ring structure-containing (meth) acrylic monomer include the above-mentioned methacrylic acid esters, acrylic acid esters, and other copolymerizable vinyl monomers. Although the mer can be used as well, it is preferred to include methacrylic acid esters and acrylic acid esters.

The methacrylic acid ester is preferably contained in an amount of 0 to 98% by weight in a total amount of 100% by weight of the above-mentioned ring structure-containing vinyl monomer and other monofunctional monomers copolymerizable therewith, More preferably, it is contained in an amount of ˜98% by weight, more preferably 1 to 94% by weight, and particularly preferably 30 to 90% by weight.
The acrylic ester is preferably contained in an amount of 0 to 98% by weight in the total amount of 100% by weight of the above-mentioned ring structure-containing vinyl monomer and other monofunctional monomers copolymerizable therewith. More preferably, it is contained in an amount of 1 to 98% by weight, more preferably 1 to 50% by weight, and particularly preferably 5 to 50% by weight.

The graft ratio of the acrylic ester rubbery polymer particles is preferably 10 to 250%, more preferably 40 to 230%, and most preferably 60 to 220%.
When the graft ratio is less than 10%, the acrylic graft copolymer particles tend to aggregate in the film, which may reduce transparency and cause foreign matter. Moreover, there exists a tendency for the elongation at the time of a tensile fracture to fall and to become easy to generate | occur | produce a crack at the time of film cutting. If it exceeds 250%, for example, the melt viscosity at the time of film formation increases, and the moldability of the film tends to decrease.

The graft ratio is a weight ratio of the graft component in the acrylic graft copolymer particles, and is measured, for example, by the following method.
Dissolve 2 g of acrylic graft copolymer particles in 50 ml of methyl ethyl ketone, and centrifuge for 1 hour at a rotational speed of 30000 rpm and a temperature of 12 ° C. using a centrifuge (manufactured by Hitachi Koki Co., Ltd., CP60E). Separate into solutes (centrifuged for a total of 3 sets). From the weight of the obtained insoluble matter and the weight of the acrylate rubber polymer contained in the acrylic graft copolymer particles, the graft ratio is calculated by the following formula.
Graft ratio (%) = [{(weight of methyl ethyl ketone insoluble matter) − (weight of acrylic ester rubber-like polymer)} / (weight of acrylic ester rubber-like polymer)] × 100

The acrylic graft copolymer particles can be produced by a general emulsion polymerization method. Specifically, a method of continuously polymerizing an acrylate monomer using an emulsifier in the presence of a water-soluble polymerization initiator can be exemplified.
In the emulsion polymerization method, it is preferable to carry out continuous polymerization in a single reaction tank, and using two or more reaction tanks is not preferable because the mechanical stability of the latex decreases.
The polymerization temperature is preferably 30 ° C. or higher and 100 ° C. or lower, more preferably 50 ° C. or higher and 80 ° C. or lower. If the temperature is lower than 30 ° C., the productivity tends to decrease, and if the temperature exceeds 100 ° C., the quality tends to decrease due to the excessive increase in the target molecular weight.
Raw materials such as monomers, initiators, emulsifiers and deionized water that are continuously added to the polymerization reactor are added accurately under the control of the metering pump, but the amount of heat removed from the polymerization heat generated in the reactor. In order to ensure this, there is no problem even if it is cooled in advance if necessary.
The latex discharged from the reaction vessel may be added with a polymerization inhibitor, a coagulant, a flame retardant, an antioxidant, and a pH adjuster as necessary. You may go. Thereafter, the copolymer can be obtained through known methods such as coagulation, heat treatment, dehydration, washing with water, and drying.

  In emulsion polymerization, a usual polymerization initiator can be used. For example, inorganic peroxides such as potassium persulfate and sodium persulfate, organic peroxides such as cumene hydroperoxide and benzoyl peroxide, and oil-soluble initiators such as azobisisobutyronitrile are also used. These may be used alone or in combination of two or more. These initiators are used as normal redox-type polymerization initiators in combination with reducing agents such as sodium sulfite, sodium thiosulfate, sodium formaldehyde, sulfoxylate, ascorbic acid, ferrous sulfate, and disodium ethylenediaminetetraacetic acid complex. May be.

  A chain transfer agent may be used in combination with the polymerization initiator. Examples of the chain transfer agent include alkyl mercaptans having 2 to 20 carbon atoms, mercapto acids, thiophenol, carbon tetrachloride and the like, and these may be used alone or in combination of two or more.

  There is no restriction | limiting in particular regarding the emulsifier used by an emulsion polymerization method, The emulsifier for normal emulsion polymerization can be used. For example, sulfate ester surfactants such as sodium alkyl sulfate, sulfonate surfactants such as sodium alkylbenzene sulfonate, sodium alkyl sulfonate, sodium dioctyl sulfosuccinate, sodium alkyl phosphate, polyoxyethylene alkyl ether Anionic surfactants such as phosphate surfactants such as sodium phosphate ester are listed. The sodium salt may be other alkali metal salt such as potassium salt or ammonium salt. These emulsifiers may be used alone or in combination of two or more. Furthermore, nonionic surfactants represented by polyoxyalkylenes or alkyl-substituted or aryl-substituted terminal hydroxyl groups may be used or partially used together. Among these, from the viewpoint of polymerization reaction stability and particle system controllability, sulfonate surfactants or phosphate surfactants are preferable. Among them, dioctylsulfosuccinate or polyoxyethylene alkyl ether phosphate is preferable. Ester salts can be used more preferably.

  The use amount of the emulsifier is preferably 0.05 part by weight or more and 10 parts by weight, and more preferably 0.1 part by weight or more and 1.0 part by weight or less with respect to 100 parts by weight of the whole monomer component. If the amount is less than 0.05 parts by weight, the particle size of the copolymer tends to be too large. If the amount is more than 10 parts by weight, the particle size of the graft copolymer tends to be too small, and the particle size distribution tends to deteriorate. is there.

The multilayer structure particles described above and the thermoplastic resin are mixed to obtain the first thermoplastic resin composition.
Prior to producing the film, the multilayer structure particles and the thermoplastic resin may be uniformly pelletized according to a conventional method, or may be mixed in an extruder at the time of film production.
The amount of the multilayer structured particles used is not particularly limited as long as the object of the present invention is not impaired. 0.1-2.0 weight part is preferable with respect to 100 weight part of thermoplastic resins, and, as for the usage-amount of multilayer structure particle, 0.2-1.5 weight part is more preferable.
When the amount of the multilayer structure particles used is less than 0.1 parts by weight, it is difficult to give the desired degree of lubricity to the portion of the resulting film made of the first resin composition, and the blocking is caused when the film is wound. Defects are likely to occur.
Moreover, when there are more usage-amounts of multilayer structure particle than 2.0 weight part, excessive lubricity will be given to a film and a conveyance trouble may arise.

(Other ingredients)
The 1st thermoplastic resin composition may contain the antioxidant for improving the stability with respect to a heat | fever and light, the ultraviolet absorber, the ultraviolet stabilizer, etc. individually or in combination of 2 or more types other than multilayer structure particle | grains.

Moreover, the 1st thermoplastic resin composition may contain rubber particles other than the multilayer structure particle mentioned later about the 2nd thermoplastic resin composition.
When the first thermoplastic resin composition contains rubber particles other than the multilayer structure particles, toughness is imparted to the central portion of the film, and as a result, fine powder accompanying cracks in the film in the transport process and slit defects in the slit portion. Is less likely to occur and productivity can be improved.

  The content of the rubber particles other than the multilayer structured particles in the first thermoplastic resin composition is 3 parts by weight or more and 30 parts by weight or less when the thermoplastic resin and the rubber particles other than the multilayer structured particles are combined to 100 parts by weight. Preferably, it is 5 parts by weight or more and 20 parts by weight or less. If it is less than 3 parts by weight, toughness cannot be imparted sufficiently, such being undesirable. On the other hand, when the amount is more than 30 parts by weight, the melt viscosity increases and molding becomes difficult.

<Second thermoplastic resin composition>
As described above, in the co-extrusion in the first production method, at least the first thermoplastic resin composition and the second thermoplastic resin composition are used.
The second thermoplastic resin composition does not include the multilayer structure particles described above, or includes a smaller amount of multilayer structure particles than the first thermoplastic resin composition.
For this reason, both ends of the film made of the second thermoplastic resin composition are poor in slipperiness, and as a result, meandering during film conveyance is suppressed, generation of wrinkles and scratches on the film, and winding deviation are also suppressed. .
Hereinafter, essential or optional components contained in the second thermoplastic resin composition will be described.

(Thermoplastic resin)
The thermoplastic resin contained in the second thermoplastic resin composition is the same as that described for the first thermoplastic resin composition.
Similar to the first thermoplastic resin composition, from the viewpoint of transparency, the second thermoplastic resin composition preferably contains an acrylic resin as the thermoplastic resin.
The acrylic resin is preferably the heat-resistant acrylic resin described for the first thermoplastic resin composition.

(Multilayer structure particles with rubber part)
When the 2nd thermoplastic resin composition contains the multilayer structure particle which has a rubber part, the multilayer structure particle is the same as that explained about the 1st thermoplastic resin composition.
The content of the multilayer structure particles in the second thermoplastic resin composition is not particularly limited as long as it is less than the content of the multilayer structure particles in the first thermoplastic resin composition.
The content of the multilayer structure particles in the second thermoplastic resin composition is preferably 50% by weight or less, more preferably 30% by weight or less, and more preferably 10% by weight or less of the content of the multilayer structure particles in the first thermoplastic resin composition. Is particularly preferred.
In particular, it is most preferable that the second thermoplastic resin composition does not contain multilayer structure particles from the viewpoint of excellent effect of suppressing meandering during film conveyance.

(Rubber particles)
The second thermoplastic resin composition preferably contains rubber particles other than the multilayer structured particles.
When the second thermoplastic resin composition contains rubber particles other than the multilayer structure particles, toughness is imparted to both ends of the film, and as a result, fine powder accompanying cracks in the film in the transport process and slit defects in the slits. Is less likely to occur and productivity can be improved.

The rubber particles are not particularly limited as long as they do not impair the object of the present invention and are different from the above-mentioned multilayer structure particles.
The rubber particles preferably have a multilayer structure composed of a core composed of a rubber portion and one or more shell layers, as in the case of the multilayer structured particles described above. Due to the presence of the shell layer, the compatibility with the thermoplastic resin to be mixed is improved, and the particles can be uniformly dispersed. Although rubber particles without a shell layer can be used, when rubber particles without a shell layer are mixed with a thermoplastic resin, the rubber particles are difficult to uniformly disperse and the transparency of the film may be lowered.
The glass transition temperature of the rubber part is not particularly limited, but is preferably less than 20 ° C.

The degree of cross-linking of the rubber part contained in the rubber particles is preferably less than 2.3% by weight, and the lower the better, the lower the lubricity at both ends of the film.
The particle diameter of the rubber part contained in the rubber particles is not particularly limited, but is preferably the same as the particle diameter of the rubber part contained in the multilayer structure particle.

  Suitable rubber particles having a multilayer structure can be produced by the same material and the same method as the multilayer structure particles described for the first thermoplastic resin composition, except that the degree of crosslinking of the rubber part is different.

  The content of rubber particles other than the multilayer structured particles in the second thermoplastic resin composition is preferably the same as the content of rubber particles in the first thermoplastic resin composition. If there is a large difference in the content of rubber particles between the first thermoplastic resin and the second thermoplastic resin, the melt elongation at the time of discharging from the T-die and stretching it into a film shape is the first thermoplastic resin region 2 It changes with the area | region which consists of thermoplastic resins, and since it has influences, such as a film thickness fluctuating, it is unpreferable. The difference in the rubber particle content between the first thermoplastic resin and the second thermoplastic resin is preferably within ± 30%.

(Other ingredients)
The second thermoplastic resin composition contains, in addition to the multilayer structure particles and rubber particles, an antioxidant, an ultraviolet absorber, an ultraviolet stabilizer and the like for improving the stability to heat and light, alone or in combination. May be.

<Optical film>
According to the first manufacturing method described above, with respect to the width direction of the optical film,
The central part is a first region including multilayer structure particles having a rubber part having a degree of crosslinking of 2.3% to 4.0% and a particle diameter of 180 nm to 400 nm,
Both end portions can produce an optical film that is a second region that does not contain multi-layer structured particles or is in a lower amount than the first region.

Since it is easy to suppress the occurrence of blocking-induced defects and the meandering of the film, the static friction coefficient in the first region (load 200 g, FS 50%) is preferably 0.2 or more and 0.8 or less, and the static friction coefficient in the second region ( The load (200 g, FS 50%) is preferably 0.6 or more.
Note that the static friction coefficient in the second region is higher than the static friction coefficient in the first region. The static friction coefficient in the second region is preferably 0.1 or more higher than the static friction coefficient in the first region.

  Such optical film suppresses the occurrence of defects due to blocking such as scratches and irregularities caused by contact between films, and the occurrence of wrinkles and scratches on the film due to film meandering and the occurrence of winding displacement. Have been high quality.

Here, the width of the second region in the film width direction is not particularly limited as long as the object of the present invention is not hindered. The width of the second region is preferably 20 mm or more and more preferably 30 mm or more from both extreme ends in the width direction of the film.
Moreover, it is preferable that the sum total of the width | variety of 2nd area | region is 15% or less with respect to the film full width.
Although the preferable value of the upper limit of the width of the second region varies depending on the total width of the film, typically, the width of the second region is preferably 150 mm or less from both extreme ends in the width direction of the film, more preferably 100 mm or less. preferable.

  The above optical film may be used after the second region is excised by a method such as slit processing.

«Second manufacturing method»
Hereinafter, the width | variety of 1st thermoplastic resin composition containing slippery particle | grains, and the 2nd thermoplastic resin composition which does not contain slippery particle | grains or is contained in the amount lower than 1st thermoplastic resin composition are the width | variety of die | dye exit. A method for producing an optical film that is coextruded from different locations in the direction and formed into a film shape is referred to as a second production method.

Regarding the second production method, the multilayer structure particles, which are essential components of the first thermoplastic resin composition described for the first production method, have been changed to slip particles described later.
About the other point, the 1st thermoplastic resin composition used in the 2nd manufacturing method is the same as the 1st thermoplastic resin composition used in the 1st manufacturing method.
In addition, in the second thermoplastic resin composition, instead of the above-mentioned multilayer structure particles, slipping particles described later are blended in a smaller amount than the amount in the first thermoplastic resin composition, if necessary.

Furthermore, in the second manufacturing method, the first thermoplastic resin composition and the second thermoplastic resin composition may be discharged from different locations in the width direction at the die outlet.
The location where the second thermoplastic resin composition is discharged is not limited to both ends of the die outlet in the width direction.
The location where the second thermoplastic resin composition is discharged may be one location or a plurality of locations of two or more locations. When the location where the second thermoplastic resin composition is discharged is a plurality of locations of two or more locations, the shift during film transportation is remarkable for the region sandwiched between the plurality of regions composed of the second thermoplastic resin composition. To be suppressed.

The slippery particle is not particularly limited as long as it can impart lubricity to the film, and various particulate additives conventionally used for the purpose of imparting slipperiness to a transparent resin composition may be used. it can.
Here, the slippery particles are obtained by forming a film of a thermoplastic resin composition comprising 85 parts by weight of a thermoplastic resin and 0.5 parts by weight of the particles, and calculating the static friction coefficient (load 200 g, FS 50%) of the obtained film. When it is set to A, the said A says the particle | grains which are 60% or less with respect to the static friction coefficient (load 200g, FS50%) B of the film which consists only of a thermoplastic resin.
The film for measuring A and the film for measuring B are created under the same conditions.

Specific examples of the lubricious particles include inorganic particles such as silica such as colloidal silica, kaolin, talc, aluminum oxide, calcium hydroxide, magnesium oxide, glass particles, feldspar, and zeolite, acrylic particles, and silicone resin particles. , Polyimide resin particles, and organic particles such as Teflon (registered trademark) particles.
Moreover, the multilayer structure particle described about the 1st manufacturing method can also be used as a lubricous particle.

Furthermore, organic crosslinked polymer particles can also be used as slipping particles. Examples of organic crosslinked polymer particles include monofunctional monomers such as methyl methacrylate and polyfunctional monomers such as trimethylolpropane tri (meth) acrylate, allyl (meth) acrylate, and ethylene glycol di (meth) acrylate. And (meth) acrylic crosslinked particles obtained by suspension polymerization (see Japanese Patent No. 4034157).
Styrene (meth) acryl crosslinked particles obtained by further copolymerizing styrene monomers such as styrene, α-methylstyrene, divinylbenzene, etc. may be used during suspension polymerization. Moreover, at least 1 sort (s) chosen from a (meth) acrylic acid monomer, a (meth) acrylic acid ester monomer, and a styrene-type monomer was obtained by carrying out emulsion polymerization, soap free emulsion polymerization, miniemulsion polymerization, dispersion polymerization, or seed polymerization ( It may be meth) acrylic crosslinked particles or styrene- (meth) acrylic crosslinked particles.

  Organic-inorganic composite particles can also be used as the lubricating particles. The organic-inorganic composite particles are composed of an organic part and an inorganic part. The content of the inorganic part in the organic-inorganic composite particles is, for example, 0.5 to 90% by weight, preferably 1 to 70% by weight, and more preferably 2 to 60% by weight in terms of inorganic oxide. Here, the content in terms of inorganic oxide specifically refers to the weight of the organic-inorganic composite particles remaining when the particles are fired at a high temperature (for example, 1000 ° C. or higher) in an oxidizing atmosphere such as air. It is a numerical value represented by the ratio of the weight of the inorganic oxide.

Preferred specific examples of the organic-inorganic composite particles include an organic polymer skeleton described in JP-A-8-81561, and organic silicon in which a silicon atom is directly chemically bonded to at least one carbon atom in the skeleton. Particles having a polysiloxane skeleton having a content of SiO ₂ constituting the polysiloxane skeleton of 25% by weight or more, and a (meth) acryloxy group described in JP-A No. 2003-183337 This is a particle in which a vinyl polymer is contained in the structure of polysiloxane particles.

  The content of the slippery particles in the first thermoplastic resin composition is the same as the content of the multilayer structure particles in the first thermoplastic resin composition used in the first production method.

According to the 2nd method, the 1st area | region to which lubricity was provided is formed in a film with the 1st thermoplastic resin composition containing lubricous particle. Thereby, generation | occurrence | production of the defect resulting from blocking like the generation | occurrence | production of a damage | wound and an unevenness | corrugation produced by the contact of films, etc. is suppressed.
Moreover, the 2nd area | region with poor lubricity is formed in a film with the 2nd thermoplastic resin composition which does not contain lubricating particles or contains only a small amount. Thereby, meandering during film conveyance is suppressed, and as a result, generation of wrinkles and scratches on the film and occurrence of winding deviation are suppressed.

The area in the width direction where the second thermoplastic resin composition is discharged at the die outlet may be one or two or more.
It is preferable that the area | region regarding the width direction in which a 2nd thermoplastic resin composition is discharged is two or more places, and it is preferable that the said 2 places are the both ends regarding the width direction of die | dye exit.

Here, the total width of the region in the width direction in which the second thermoplastic resin composition is discharged at the die outlet is not particularly limited as long as the desired effect is obtained, and is preferably 40 mm or more, more preferably 60 mm or more. .
Moreover, it is preferable that the sum total of the width | variety of the area | region regarding the width direction in which the 2nd thermoplastic resin composition is discharged in die exit is 15% or less with respect to the full width of die | dye.
In addition, although the preferable value of the upper limit of the sum total of the width | variety of the area | region regarding the width direction in which a 2nd thermoplastic resin composition is discharged differs with the full width of a film, typically 300 mm or less is preferable and 200 mm or less is more preferable.

When the second thermoplastic resin composition is discharged from both end portions in the width direction of the die exit, the width of both end portions in the width direction of the die exit is not particularly limited as long as the object of the present invention is not hindered. The width of both end portions is preferably 20 mm or more, more preferably 30 mm or more from both extreme ends of the die outlet 12.
Moreover, it is preferable that the sum total of the width | variety of both ends is 15% or less with respect to the full width of die | dye.
The preferable value of the upper limit of the width at both ends varies depending on the total width of the film. Typically, the width at both ends is preferably 150 mm or less, more preferably 100 mm or less from both extreme ends of the die outlet 12.

According to the first manufacturing method described above, with respect to the width direction of the optical film,
A first region containing lubricious particles;
An optical film having a second region that does not include slippery particles or that includes a lower amount than the first region can produce an optical film.

Since it is easy to suppress the occurrence of blocking-induced defects and the meandering of the film, the static friction coefficient in the first region (load 200 g, FS 50%) is preferably 0.2 or more and 0.8 or less, and the static friction coefficient in the second region ( The load (200 g, FS 50%) is preferably 0.6 or more.
Note that the static friction coefficient in the second region is higher than the static friction coefficient in the first region. The static friction coefficient in the second region is preferably 0.1 or more higher than the static friction coefficient in the first region.

  Such optical film suppresses the occurrence of defects due to blocking such as scratches and irregularities caused by contact between films, and the occurrence of wrinkles and scratches on the film due to film meandering and the occurrence of winding displacement. Have been high quality.

Here, the width of the second region in the film width direction is not particularly limited as long as the object of the present invention is not hindered. 40 mm or more is preferable and, as for the total of the width | variety regarding the width direction of the film of a 2nd area | region, 60 mm or more is more preferable.
Moreover, it is preferable that the sum total of the width | variety of 2nd area | region is 15% or less of range with respect to the film full width.
In addition, although the preferable value of the upper limit of the sum total of the width | variety of 2nd area | regions changes with film full width, typically, the sum total of the width | variety of 2nd area | region is preferable 300 mm or less, and 200 mm or less is more preferable.

When the second region is formed at both ends in the width direction of the film, the width of each second region at both ends is not particularly limited as long as the object of the present invention is not impaired. The respective widths of the second regions at both ends are preferably 20 mm or more, more preferably 30 mm or more from both extreme ends of the die outlet 12.
Moreover, it is preferable that the sum total of the width | variety of the 2nd area | region of both ends is 15% or less of range with respect to the full width of a film.
In addition, although the preferable value of the upper limit of the width | variety of the 2nd area | region of both ends differs with the full width of a film, typically, the width | variety of the 2nd area | region of both ends is preferably 150 mm or less from the both extreme ends of a film, 100 mm or less is more preferable.

  The above optical film may be used after the second region is excised by a method such as slit processing.

  The optical film that can be manufactured by the first manufacturing method and the second manufacturing method described above is a member used for a display device such as a liquid crystal display device or an organic EL device, such as a polarizing plate protective film or a retardation film. , Brightness enhancement films, liquid crystal substrates, light diffusion sheets, prism sheets and the like. Especially, it is suitable for a polarizing plate protective film and retardation film.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example, this invention is not limited to these Examples.

The measuring method of each physical property measured in the following examples and comparative examples is as follows.
(Average particle diameter of rubber part of multilayer structure particles)
Using the obtained polymer latex diluted to a solid content concentration of 0.02% as a sample, using light scattering at a wavelength of 546 nm using a U-5100 ratio beam spectrophotometer manufactured by Hitachi High-Technologies Corporation. Asked.
(Glass-transition temperature)
Using a differential scanning calorimeter (DSC) SSC-5200 manufactured by Seiko Instruments Inc., the sample was once heated to 200 ° C. at a rate of 25 ° C./minute, held for 10 minutes, and then at a rate of 25 ° C./minute to 50 ° C. Measurement is performed while the temperature is raised to 200 ° C. at a rate of temperature increase of 10 ° C./min through preliminary adjustment to lower the temperature, and an integral value is obtained from the obtained DSC curve (DDSC), and the glass transition temperature is determined from the maximum point. Asked.
(Winding misalignment)
The deviation of the end of the rolled up film roll was measured with a caliper, and evaluated as no (less than 1 mm) (small), slightly generated larger than 1 mm and smaller than 3 mm (△), and larger than 3 mm (×). did.
(Blocking-induced defects)
When a high-intensity light is applied to the rolled film roll from the end, there is no occurrence of color shade (○), slight occurrence of color shade (△), high-intensity light Occurrence (×) was observed when color shading was observed under a fluorescent lamp without using.

(Production Example 1)
<Production Example 1: Production of acrylic resin (A1)>
In Production Example 1, an acrylic resin (A1) which is a glutarimide acrylic resin was produced using polymethyl methacrylate (A2) as a raw material resin and monomethylamine as an imidizing agent.
In this production, a tandem reaction extruder in which two extrusion reactors were arranged in series was used.
As for the tandem type reactive extruder, the meshing type co-directional twin-screw extruder having a diameter of 75 mm for both the first and second extruders and L / D (ratio of the length L to the diameter D of the extruder) of 74. The raw material resin was supplied to the raw material supply port of the first extruder using a constant weight feeder (manufactured by Kubota Corporation).
The degree of vacuum of each vent in the first extruder and the second extruder was set to -0.095 MPa. Furthermore, the pressure control mechanism in the part connects the first extruder and the second extruder with a pipe having a diameter of 38 mm and a length of 2 m, and connects the resin discharge port of the first extruder and the raw material supply port of the second extruder. Used a constant flow pressure valve.
The resin (strand) discharged from the second extruder was cooled by a cooling conveyor and then cut by a pelletizer to form pellets. Here, in order to determine the pressure in the part connecting the resin discharge port of the first extruder and the raw material supply port of the second extruder, or to determine the extrusion fluctuation, the discharge port of the first extruder, the first extruder and the first extruder Resin pressure gauges were provided at the center of the connecting parts between the two extruders and at the discharge port of the second extruder.
In the 1st extruder, the polymethyl methacrylate resin (Mw: 105,000) was used as raw material resin, and the imide resin intermediate body 1 was manufactured using monomethylamine as an imidation agent. At this time, the temperature of the highest temperature part of the extruder was 280 ° C., the screw rotation speed was 55 rpm, the raw material resin supply amount was 150 kg / hour, and the addition amount of monomethylamine was 2.0 parts with respect to 100 parts of the raw material resin. The constant flow pressure valve was installed immediately before the raw material supply port of the second extruder, and the monomethylamine press-fitting portion pressure of the first extruder was adjusted to 8 MPa.
In the second extruder, the imidizing agent and by-products remaining in the rear vent and the vacuum vent were devolatilized, and then dimethyl carbonate was added as an esterifying agent to produce an imide resin intermediate 2. At this time, each barrel temperature of the extruder was 260 ° C., the screw rotation speed was 55 rpm, and the addition amount of dimethyl carbonate was 3.2 parts with respect to 100 parts of the raw resin. Furthermore, after removing the esterifying agent with a vent, it was extruded from a strand die, cooled in a water tank, and then pelletized with a pelletizer to obtain an acrylic resin (A1).
The obtained acrylic resin (A1) is an acrylic resin obtained by copolymerizing a glutamylimide unit and a (meth) acrylic ester unit.

<Production Example 2: Production of rubber particles (B1)>
In Production Example 2, rubber particles (B1) that are non-slip particles were produced.
The following substances were charged into an 8 L polymerization apparatus equipped with a stirrer.
Deionized water 200 parts Polyoxyethylene lauryl ether sodium phosphate 0.05 parts sodium formaldehyde sulfoxylate 0.11 parts ethylenediaminetetraacetic acid-2-sodium 0.004 parts ferrous sulfate 0.001 parts Was sufficiently substituted with nitrogen gas to make it substantially free of oxygen, and the internal temperature was set to 40 ° C., and a raw material mixture of acrylic rubber particles (rubber part particles) (90% butyl acrylate, 10% methyl methacrylate) 45.491 parts of allyl methacrylate and 0.041 parts cumene hydroperoxide) were continuously added to 45 parts by weight of the monofunctional monomer consisting of 225 minutes. Polyoxyethylene lauryl ether sodium phosphate (polyoxyethylene lauryl ether phosphate (trade name: Phosphanol RD-510Y, manufactured by Toho Chemical Co., Ltd.) 20 minutes, 40 minutes and 60 minutes after the start of addition of the raw material mixture The sodium salt was added to the polymerization machine 0.2 parts at a time, and the polymerization was continued for another 0.5 hours to obtain rubber part particles, with a polymerization conversion rate of 98.6%.
Thereafter, the internal temperature was set to 60 ° C., 0.2 parts of sodium formaldehyde sulfoxylate was charged, and then the shell layer raw material mixture (methyl methacrylate 57.8%, butyl acrylate 4%, benzyl methacrylate 38 .55% by weight of a monofunctional monomer composed of 2%, 0.355 parts of t-dodecyl mercaptan, 0.254 parts of cumene hydroperoxide) was continuously added over 210 minutes, The polymerization was further continued for 1 hour to obtain a graft copolymer latex (core-shell structure rubber particles). The polymerization conversion rate was 100.0%. The obtained latex was salted out and coagulated with magnesium sulfate, washed with water and dried to obtain white powdery rubber particles (B1).
The average particle size of the rubber particles (B1) was 121 nm. The graft ratio of the rubber particles (B1) was 56%.

<Production Example 3: Production of multilayer structured particle (B2)>
In Production Example 3, multilayer structured particles (B2), which are particles that impart lubricity to the film, were produced.
The following materials were charged into a glass reactor:
Ion-exchanged water 125 parts Boric acid 0.47 parts Sodium carbonate 0.05 parts Polyoxyethylene lauryl ether phosphoric acid 0.0042 parts After sufficiently replacing the inside of the polymerization machine with nitrogen gas, the internal temperature is brought to 80 ° C, and the monomer 25% of a mixture consisting of 17.5 parts (n-butyl acrylate 3%, methyl methacrylate 97%), allyl methacrylate 0.17 parts and t-butyl hydroperoxide 0.065 parts is batched into the polymerizer. Then, 0.00645 part of 5% sodium formaldehyde sulfoxylate, 0.0056 part of ethylenediaminetetraacetic acid-2-sodium, and 0.0014 part of ferrous sulfate were added, and t-butyl was added 15 minutes later. 0.022 part of hydroperoxide was added and the polymerization was continued for another 15 minutes. Thereafter, 0.013 part of a 2% aqueous sodium hydroxide solution was added. The remaining 75% was added continuously over 30 minutes. 30 minutes after the completion of the addition, 0.0069 part of 69% t-butyl hydroperoxide was added and maintained at the same temperature for 30 minutes to complete the polymerization. The polymerization conversion rate was 98%.
Thereafter, the obtained polymer latex was kept at 80 ° C. in a nitrogen stream, and 0.0346 parts of sodium hydroxide and 0.0519 parts of potassium persulfate were added. Thereafter, a mixture of 32.5 parts of monomer (82% of n-butyl acrylate and 18% of styrene), 0.97 part of allyl methacrylate and 0.3 part of polyoxyethylene lauryl ether phosphoric acid was continuously added over 74 minutes. did. Thereafter, it was held for 45 minutes to complete the polymerization. The average particle diameter of the obtained polymer was 260 nm, and the polymerization conversion rate was 99%.
Further, the obtained polymer latex was kept at 80 ° C., and after adding 0.0097 part of potassium persulfate and 0.05 part of sodium hydroxide, 50 parts of monomer (90% methyl methacrylate, n-butyl acrylate) 10%) was added continuously over 150 minutes. After completion of the addition of the mixture, it was kept for 1 hour to obtain a latex of multilayer structure particles (B2).
The average particle diameter of the multilayer structure particles was 380 nm, and the polymerization conversion rate was 99%.
The resulting multilayer structured particle latex was salted out and coagulated with magnesium sulfate, washed with water and dried to obtain white powdered multilayer structured particles (B2).

<Production Example 4: Production of resin pellet (C1)>
A twin-screw extruder with a diameter of 75 mm was used, the temperature setting zone of the extruder was set to 255 ° C., the screw rotation speed was set to 70 rpm, 85 parts by weight of acrylic resin (A1), and white powdery rubber particles (B1) A mixture of 15 parts by weight and 0.5 parts by weight of white powdery multilayer structure particles (B2) was supplied at a rate of 150 kg / hr. The resin that came out as a strand from a die provided at the exit of the extruder was cooled in a water tank and pelletized with a pelletizer. The glass transition temperature Tg of the resin pellet (C1) was 119 ° C.

<Production Example 5: Production of resin pellet (C2)>
Pellets were produced in the same manner as in the production of resin pellets (C1) except that the multilayer structured particles (B2) were not added to the resin pellets (C1).

<Production Example 6: Production of resin pellet (C3)>
Pellets were produced in the same manner as in the production of resin pellets (C1) except that the rubber particles (B1) were not added to the resin pellets (C1).

<Example 1>
The resin pellet (C1) obtained in Production Example 4 (glass transition temperature Tg 119 ° C.) was used at the center, and dried at 80 ° C. for 4 hours with a dryer, and then supplied to a φ90 mm single screw extruder. At the exit of the extruder, screen meshes were stacked in the order of # 40, # 100, # 400, # 400, # 100, # 40 from the extruder side. The resin was heated and melted so that the resin temperature became 250 ° C. at the exit of the extruder, and the molten resin was extruded through a gear pump to a feed block provided on the top of a 1850 mm wide T die.
Moreover, after drying the resin pellet (C2) (glass transition temperature Tg 119 degreeC) obtained by manufacture example 5 at both ends by 80 degreeC with a dryer for 4 hours, it is supplied to a Φ40mm extruder and the exit of the extruder The resin was heated and melted so that the resin temperature became 250 ° C., and the molten resin was extruded through a gear pump to a feed block provided on the top of the T die having the width of 1850 mm. At this time, it adjusted to the range of 150 mm from both ends as a both end part range.
The discharged molten resin was taken up at a line speed of 15 m / min, and sandwiched between a cast roll adjusted to 100 ° C. and a touch roll adjusted to 100 ° C., and then cooled and solidified. At this time, changes due to thickness variations at the ends and insufficient cooling were not observed until the film discharged from the T-die was cooled and solidified. Thereafter, the film was taken up by a take-up roll, and both ends 200 mm were slit in front of the take-up core to obtain an original film having a thickness of 80 μm on the take-up core. At this time, no meandering or cracking of the film before the slit was observed, no cracking or chipping occurred in the slit part, no blocking-induced defects were observed when winding, and the winding was good .
Moreover, the static friction coefficient (load 200g, FS50%) of the film center part was 0.3, and the static friction coefficient (load 200g, FS50%) of the film both ends was 1.2.

<Example 2>
It implemented similarly to Example 1 except having changed the material fed to both ends from the resin pellet (C2) to acrylic resin (A1).
The discharged molten resin was taken up at a line speed of 15 m / min, and sandwiched between a cast roll adjusted to 100 ° C. and a touch roll adjusted to 100 ° C., and then cooled and solidified. At this time, changes due to thickness variations at the ends and insufficient cooling were not observed until the film discharged from the T-die was cooled and solidified. Thereafter, the film was taken up by a take-up roll, and both ends 200 mm were slit in front of the take-up core to obtain an original film having a thickness of 80 μm on the take-up core. At this time, there was no meandering of the film before the slit, but cracking occurred twice at the film edge. Moreover, there was no generation | occurrence | production of the crack and chip in a slit part, the defect resulting from the blocking at the time of winding was not seen, and it was a favorable winding form.
Moreover, the static friction coefficient (load 200g, FS50%) of the film center part was 0.3, and the static friction coefficient (load 200g, FS50%) of the film both ends was 1.8.

<Example 3>
It implemented like Example 1 except having changed the material fed to a center part into resin pellet (C3) (glass transition temperature Tg119 degreeC) from the resin pellet (C1).
The discharged molten resin was taken up at a line speed of 15 m / min, and sandwiched between a cast roll adjusted to 100 ° C. and a touch roll adjusted to 100 ° C., and then cooled and solidified. At this time, changes due to thickness variations at the ends and insufficient cooling were not observed until the film discharged from the T-die was cooled and solidified. Thereafter, the film was taken up by a take-up roll, and both ends 200 mm were slit in front of the take-up core to obtain an original film having a thickness of 80 μm on the take-up core. At this time, there was no meandering of the film before the slit, but a crack occurred once at the end of the film. In addition, chips were finely generated in the slit portion and remained slightly adhered to the film as foreign matter. However, there was no blocking-induced defect when wound, and the wound shape was good.
Moreover, the static friction coefficient (load 200g, FS50%) of the film center part was 0.5, and the static friction coefficient (load 200g, FS50%) of the film both ends was 1.2.

<Example 4>
The material fed to the central part was changed from the resin pellet (C1) to the resin pellet (C3) (glass transition temperature Tg 119 ° C.), and the material fed to both ends was changed from the resin pellet (C2) to the acrylic resin. It implemented similarly to Example 1 except having changed into (A1).
The discharged molten resin was taken up at a line speed of 15 m / min, and sandwiched between a cast roll adjusted to 100 ° C. and a touch roll adjusted to 100 ° C., and then cooled and solidified. At this time, changes due to thickness variations at the ends and insufficient cooling were not observed until the film discharged from the T-die was cooled and solidified. Thereafter, the film was taken up by a take-up roll, and both ends 200 mm were slit in front of the take-up core to obtain an original film having a thickness of 80 μm on the take-up core. At this time, there was no meandering of the film before the slit, but cracking occurred twice at the film edge. In addition, chips were finely generated in the slit portion and remained slightly adhered to the film as foreign matter. However, there was no blocking-induced defect when wound, and the wound shape was good.
Moreover, the static friction coefficient (load 200g, FS50%) of the film center part was 0.5, and the static friction coefficient (load 200g, FS50%) of the film both ends was 1.8.

<Comparative Example 1>
It implemented similarly to Example 1 except having changed the material fed to a center part from the resin pellet (C1) to acrylic resin (A1).
The discharged molten resin was taken up at a line speed of 15 m / min, and sandwiched between a cast roll adjusted to 100 ° C. and a touch roll adjusted to 100 ° C., and then cooled and solidified. At this time, changes due to thickness variations at the ends and insufficient cooling were not observed until the film discharged from the T-die was cooled and solidified. Thereafter, the film was taken up by a take-up roll, and both ends 200 mm were slit in front of the take-up core to obtain an original film having a thickness of 80 μm on the take-up core. At this time, there was no meandering of the film before the slit, but cracking occurred three times at the end of the film. In addition, chips were generated in the slit portion and remained as adhered foreign matter on the film. However, a significant blocking-induced defect occurred when wound.
Moreover, the static friction coefficient (load 200g, FS50%) of the film center part was 1.8, and the static friction coefficient (load 200g, FS50%) of the film both ends was 1.2.

<Comparative example 2>
The resin pellet (C3) (glass transition temperature Tg 119 ° C.) was used, dried for 4 hours at 80 ° C. with a dryer, and then supplied to a φ90 mm single screw extruder. At the exit of the extruder, screen meshes were stacked in the order of # 40, # 100, # 400, # 400, # 100, # 40 from the extruder side. The resin was heated and melted so that the resin temperature became 250 ° C. at the exit of the extruder, and the molten resin was extruded through a gear pump into a T-die having a width of 1850 mm.
The discharged molten resin was taken up at a line speed of 15 m / min, and sandwiched between a cast roll adjusted to 100 ° C. and a touch roll adjusted to 100 ° C., and then cooled and solidified. At this time, changes due to thickness variations at the ends and insufficient cooling were not observed until the film discharged from the T-die was cooled and solidified. Thereafter, the film was taken up by a take-up roll, and both ends 200 mm were slit in front of the take-up core to obtain an original film having a thickness of 80 μm on the take-up core. At this time, meandering of the film before the slit occurred. On the other hand, the film at the end was stable. Moreover, there was some generation of chips in the slit portion, and the film remained as adhered foreign matter. However, significant defects due to blocking occurred when winding, and winding misalignment also occurred.
The static friction coefficient of the entire film surface (load 200 g, FS 50%) was 0.5.

<Comparative Example 3>
The material fed to the center was changed from the resin pellet (C1) to the acrylic resin (A1), and the material fed to both ends was changed from the resin pellet (C2) to the resin pellet (C3). Except for and, it carried out like Example 1.
The discharged molten resin was taken up at a line speed of 15 m / min, and sandwiched between a cast roll adjusted to 100 ° C. and a touch roll adjusted to 100 ° C., and then cooled and solidified. At this time, changes due to thickness variations at the ends and insufficient cooling were not observed until the film discharged from the T-die was cooled and solidified. Thereafter, the film was taken up by a take-up roll, and both ends 200 mm were slit in front of the take-up core to obtain an original film having a thickness of 80 μm on the take-up core. At this time, there was no meandering of the film before the slit, and there was no crack at the end. However, chips were finely generated in the slit portion, and remained slightly adhered to the film as a foreign matter, and defects due to blocking were also generated when wound.
Moreover, the static friction coefficient (load 200g, FS50%) of the film center part was 1.8, and the static friction coefficient (load 200g, FS50%) of the film both ends was 0.5.

<Comparative Example 4>
It carried out similarly to the comparative example 2 except having replaced with the resin pellet (C3) and having used the resin pellet (C2).
The discharged molten resin was taken up at a line speed of 15 m / min, and sandwiched between a cast roll adjusted to 100 ° C. and a touch roll adjusted to 100 ° C., and then cooled and solidified. At this time, changes due to thickness variations at the ends and insufficient cooling were not observed until the film discharged from the T-die was cooled and solidified. Thereafter, the film was taken up by a take-up roll, and both ends 200 mm were slit in front of the take-up core to obtain an original film having a thickness of 80 μm on the take-up core. At this time, meandering of the film before the slit and cracking of the end portion were not observed, and although there was no cracking or chipping in the slit portion, a blocking-induced defect occurred when wound.
The static friction coefficient of the entire film surface (load 200 g, FS 50%) was 1.2.

<Comparative Example 5>
It implemented similarly to Example 1 except having changed the material fed to both ends from the resin pellet (C2) to the resin pellet (C3).
The discharged molten resin was taken up at a line speed of 15 m / min, and sandwiched between a cast roll adjusted to 100 ° C. and a touch roll adjusted to 100 ° C., and then cooled and solidified. At this time, changes due to thickness variations at the ends and insufficient cooling were not observed until the film discharged from the T-die was cooled and solidified. Thereafter, the film was taken up by a take-up roll, and both ends 200 mm were slit in front of the take-up core to obtain an original film having a thickness of 80 μm on the take-up core. At this time, meandering of the film before the slit occurred. There was no generation of cracks or chips in the slit portion, and no blocking-induced defects were observed when winding, but winding misalignment occurred and the winding appearance was poor.
Moreover, the static friction coefficient (load 200g, FS50%) of the film center part was 0.3, and the static friction coefficient (load 200g, FS50%) of the film both ends was 0.5.

Table 1 below summarizes the results of Examples and Comparative Examples.

From Table 1, in Examples, while suppressing the slipperiness at both ends by not containing the multilayer structure particles, by adding slipperiness to the central part by including the multilayer structure particles, it is possible to prevent winding misalignment and blocking. It turns out that the malfunction which originates can be suppressed.
On the other hand, according to the comparative example, depending on the presence or absence of multi-layer structured particles, when the slipperiness at both ends of the film is not designed to be lower than the slipperiness at the center of the film, suppression of winding misalignment and inconvenience due to blocking It can be seen that suppression cannot be achieved at the same time.

DESCRIPTION OF SYMBOLS 10 Coextrusion machine 11 T die 12 Die exit 13 Thermoplastic resin composition 14 Elastic roll 15 Cast roll

Claims (11)

  A first thermoplastic resin composition containing multilayer structure particles having a rubber part having a degree of cross-linking of 2.3 wt% or more and 4.0 wt% or less and a particle diameter of 180 nm or more and 400 nm or less relates to the width direction of the die exit From the central part, a second thermoplastic resin composition that does not contain the multilayer structure particles or contains a lower amount than the first thermoplastic resin composition is coextruded from both ends in the width direction of the die outlet, and is formed into a film. A method for producing an optical film to be molded.   The method according to claim 1, wherein the second thermoplastic resin composition includes rubber particles other than the multilayer structure particles.   The width of the die outlet of the first thermoplastic resin composition containing slipping particles and the second thermoplastic resin composition not containing the slipping particles or containing a lower amount than the first thermoplastic resin composition A method for producing an optical film, which is co-extruded from different locations in the direction and formed into a film shape.   The method according to claim 3, wherein the second thermoplastic resin composition is extruded from two or more portions in the width direction of the die outlet.   The method according to claim 4, wherein the second thermoplastic resin composition is extruded from both ends of the die outlet.   The method according to claim 1, wherein the first thermoplastic resin composition contains an acrylic resin.   The method according to any one of claims 1 to 6, wherein the second thermoplastic resin composition contains an acrylic resin. An optical film containing a thermoplastic resin,
Regarding the width direction of the optical film,
The central part is a first region including multilayer structure particles having a rubber part having a degree of crosslinking of 2.3% to 4.0% and a particle diameter of 180 nm to 400 nm,
Both end parts are optical films which are the 2nd field which does not contain the multilayer structure particles, or is contained in the quantity lower than the 1st field. An optical film containing a thermoplastic resin,
Regarding the width direction of the optical film,
A first region containing lubricious particles;
An optical film having a second region that does not contain the slipping particles or that contains a lower amount than the first region.   The optical film according to claim 9, wherein the second region includes two or more regions in the width direction of the optical film.   The optical film according to claim 10, wherein the second region includes both end portions in the width direction of the optical film.

Images