JP2016203384A - Production method of optical film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method of an optical film in which a film projection defect is suppressed and which has high transparency.SOLUTION: A production method of a rubber particle-containing optical film comprises: a step for supplying a thermoplastic resin composition to an extruder; a step for turning the thermoplastic resin composition into a molten state by the extruder; a step for passing the thermoplastic resin composition which is turned into the molten state in the step for turning the thermoplastic resin composition into the molten state through a filter for filtering the resin composition; and a step for molding the thermoplastic resin composition which has passed through the filter into a film. In the production method of the rubber particle-containing optical film, in the supplying step, when starting an operation of the extruder, the thermoplastic resin composition is a thermoplastic resin composition A containing no rubber particle, and in the filtering step, at a stage in which an in-filter resident time of the thermoplastic resin composition A becomes 10-30 minutes, the thermoplastic resin composition to be supplied to the extruder is switched from the thermoplastic resin composition A containing no rubber particle to a rubber particle-containing thermoplastic resin composition B.SELECTED DRAWING: None

Description

  The present invention relates to a method for producing an optical film.

  Optical films represented by a polarizer protective film for protecting the polarizer and a film substrate for liquid crystal display, etc. are clean with no contaminants in the film, optical transparency, and optical properties. Homogeneity is required.

  As a method for producing such an optical film, a resin composition as a film raw material is melted by a melt extruder, the molten resin is passed through a microfiltration filter to remove foreign matters, and then formed into a film form from a die. A melt extrusion method is known.

  As a filter for removing such foreign matter, Patent Document 1 describes a leaf disk type polymer filter.

  Patent Document 2 discloses that a film obtained from a resin composition comprising a multilayer acrylic polymer and a methacrylic polymer using a specific acrylic ester rubber-like polymer has little stress whitening, It describes that the hardness is high, the transparency is excellent, the weather resistance is excellent, the tensile elongation at break is large, the crack is hardly generated at the time of cutting the film, and the moldability and the surface property are also excellent.

JP 2013-007060 A JP 2004-137299 A

  An object of this invention is to provide the manufacturing method of an optical film which suppresses a film convex defect and has high transparency.

  The present inventor uses, as the thermoplastic resin composition for producing an optical film, the thermoplastic resin composition A that does not contain rubber particles at the start of operation of the extruder, and then the rubber particle-containing thermoplastic resin composition B. The present inventors have found that film convex defects can be suppressed and have arrived at the present invention.

  That is, the present invention was brought into a molten state in a step of supplying a thermoplastic resin composition to an extruder, a step of bringing the thermoplastic resin composition into a molten state by the extruder, and a step of bringing the thermoplastic resin composition into a molten state. In the supplying step, the extruder includes a step of filtering by passing the thermoplastic resin composition through a filter, and a step of forming the thermoplastic resin composition that has passed through the filter into a film. At the start of operation, the thermoplastic resin composition is a thermoplastic resin composition A containing no rubber particles, and in the filtering step, the residence time in the filter of the thermoplastic resin composition A is 10 to 30 minutes. In this stage, the thermoplastic composition supplied to the extruder is changed from the thermoplastic resin composition A not containing the rubber particles to the rubber particle-containing thermoplastic resin. And switches the Narubutsu B, a method for producing a rubber particle-containing optical film.

  It is preferable that the composition of the thermoplastic resin composition A not containing the rubber particles is the same as the composition of the portion excluding the rubber particles of the rubber particle-containing thermoplastic resin composition B.

  The discharge amount at the start of operation of the extruder is preferably 30 to 90% with respect to the steady discharge amount.

  The film has a step of biaxially stretching the film formed by the step of forming and a step of winding the film, and the winding speed of the film formed from the thermoplastic resin composition A not containing the rubber particles is After reaching a steady state, it is preferable to switch the thermoplastic resin composition supplied to the extruder from the thermoplastic resin composition A not containing the rubber particles to the rubber particle-containing thermoplastic resin composition B. .

  The thermoplastic resin contained in the thermoplastic resin composition is preferably an acrylic resin.

  According to the present invention, it is possible to produce an optical film that suppresses film convex defects and has high transparency.

  In order to obtain a thin, high-strength film, a method in which a resin composition containing rubber particles is filtered through a microfiltration filter, a melt-extruded film is obtained, and further biaxially stretched as necessary can be considered. However, in this method, the present inventor found that when a resin composition containing rubber particles was filtered through a microfiltration filter, a lot of convex defects were generated on the film that did not occur if the resin composition was not filtered. It has been found that it will increase with time. When examined in more detail, the convex defect is an aggregate of rubber, and the rubber particles agglomerate due to a longer residence time in the microfiltration filter of the thermoplastic resin composition in the molten state when filtering with a microfiltration filter. I have identified that.

  Furthermore, it has been found that convex defects can be suppressed by suppressing the time for the thermoplastic resin composition to pass through the microfiltration filter within a time during which aggregation does not occur.

  The residence time in the filter is the time when the resin melted in the extruder starts to pass through the filter and the time when the resin filled with the filter starts to discharge from the filter outlet side. Time until.

  On the other hand, at the beginning of the operation of the extruder, it tends to be in a low resin temperature state where melt kneading becomes insufficient. With such a resin, a step of forming a film as described in detail below, a step of stretching, etc. It is difficult to carry the film at a high line speed. Therefore, normally, at the initial stage of operation of the extruder, it is necessary to reduce the amount of resin discharged from the extruder, and the residence time of the thermoplastic resin composition in the microfiltration filter becomes longer. Moreover, since it is necessary to reduce the rotation speed of an extruder screw in order to reduce the discharge amount of resin from an extruder, initial dispersion | distribution also becomes inadequate. Therefore, even if it is possible to suppress an increase in convex defects over time in a steady state by reducing the amount of resin discharged from the extruder at the beginning of operation of the extruder, convex defects are generated at the beginning of operation of the extruder. Although such convex defects at the beginning of operation tend to decrease with time under steady conditions, it takes several hours to completely disappear, so the film loss until obtaining the target optical film is very high. growing.

  Hereinafter, the manufacturing method of the optical film of this invention is demonstrated in detail.

(Melting)
A melt extrusion apparatus can be used to bring the thermoplastic resin composition into a molten state. At this time, it is preferable to quantitatively supply the thermoplastic resin composition to the melt extrusion apparatus using a gear pump or the like.

  The melt extrusion device is not particularly limited, and various types of extruders can be used. For example, a single-screw extruder, a twin-screw extruder, a multi-screw extruder, or the like can be used.

  Among them, the single screw extruder is preferable because the resin staying portion in the extruder is small, so that it is possible to prevent thermal deterioration of the resin during extrusion and the equipment cost is low.

  Moreover, it is preferable to use an extruder having a vent mechanism in order to remove residual volatile components in the resin and heating products in the extruder.

  The size (bore size) of the extruder is preferably selected in accordance with a desired discharge amount.

  As a screw used in a single-screw extruder, a general full-flight configuration having a compression ratio of about 2-3 for an extruder with or without a vent can be used, but it is special so that unmelted material does not remain. A kneading mechanism (mixing element) may be provided.

  When the thermoplastic resin composition is a rubber particle-containing thermoplastic resin composition, if the shear in the extruder is insufficient, the rubber particles are not sufficiently dispersed in the thermoplastic resin composition, and the dispersion state is poor. If the molten resin is introduced into the filter in the state, agglomeration may occur. By making the dispersion state of the rubber particles in the molten resin introduced into the filter better, it is also possible to suppress an increase in convex defects over time, so it is preferable to give sufficient shear during melt kneading of the extruder . Therefore, it is preferable to design the extruder arbitrarily while confirming the dispersion state of the rubber particles.

(filtration)
Filtration is performed by passing the thermoplastic resin composition in a molten state through a filter.

  The filter traps foreign matter contained in the raw material resin and foreign matter generated by an extruder or gear pump, and reduces foreign matter defects in the optical film. The filter is preferably a microfiltration filter. Examples of the microfiltration filter include a screen mesh, a pleated filter, and a leaf disk filter. Among these, use of a leaf disk filter is preferable from the viewpoint of the time required until the filtration accuracy is further reduced and the filter is clogged with foreign matter because filtration with a small volume and a large filtration area is possible. The filter medium used can be a sintered non-woven fabric of metal fibers, and the filter filtration accuracy is selected from 1 to 20 μm cut, preferably 2 to 10 μm cut, most preferably 2 to 5 μm cut for optical applications. It is preferable to do. Note that the X μm cut of the filtration accuracy mentioned here indicates the accuracy with which a test powder of X μm size can be cut by 95% in a filter manufacturer's filtration test. As a result, it is possible to remove a 20 μm-sized foreign matter that is a problem in the optical film.

  In order to shorten the residence time in the filter, the number of filter elements and the filter filtration accuracy are preferably as small as possible to reduce the filter filtration accuracy within a sufficient pressure resistance range. In addition, it is preferable to design a flow path such as a gap between the parts in the filter so as to eliminate the retention of each part.

  By designing such a filter, the residence time in the filter of the thermoplastic resin composition can be set to 10 to 30 minutes.

  In an extruder, when the discharge amount in a steady state (sometimes referred to as a steady discharge amount) is designed so that the residence time in the filter of the thermoplastic resin composition is 10 to 30 minutes, the pressure loss applied to the filter As, it is necessary to set as high as 5-10 MPa. However, when the filter is designed to match the steady discharge rate, the pressure loss applied to the filter is reduced by passing a low-temperature resin that is insufficiently melted at the start of operation or immediately after the start of operation. The breakdown voltage may be exceeded. Therefore, the discharge amount at the start of operation of the extruder is preferably 30 to 90%, more preferably 35 to 85%, still more preferably 40 to 80% with respect to the steady state discharge amount. . If it is less than 30%, rubber particles are not contained and there is no concern about aggregation of the rubber particles, but the residence time in the filter becomes too long, and there is a possibility that convex defects are caused due to thermal deterioration of the thermoplastic resin composition. is there. If it exceeds 90%, the resin in a low temperature state that is insufficiently kneaded immediately after the start of the operation of the extruder or immediately after the start of earning passes through the filter with a high discharge amount, which may cause damage beyond the filter pressure resistance.

  Here, the steady state refers to a state in which the film production speed during film production is constant at a predetermined value.

  The steady discharge amount can be set to 200 to 400 kg / hr, for example, in the case of a single screw extruder of φ90 mm.

  At the start of operation of the extruder, the operation is started only with the thermoplastic resin composition A containing no rubber particles. Thereby, since the rubber particles do not exist even in the state where the initial residence time in the filter becomes long, aggregation of the rubber particles can be suppressed. Then, after the thermoplastic resin composition A that does not contain at least rubber particles is extruded from the die and then increased to the steady discharge amount, or in the process of increasing, the residence time in the filter has become 10 to 30 minutes. Thus, the thermoplastic resin composition A containing no rubber particles is continuously switched to the rubber particle-containing thermoplastic resin composition B.

  Thereby, about the rubber particle containing optical film which consists of a rubber particle containing thermoplastic resin composition B, not only the time-dependent increase of the convex defect in a steady state but the convex defect of the operation | movement start initial stage of an extruder can be suppressed. .

  When the residence time in the filter of the thermoplastic resin composition at the start of the operation of the extruder or immediately after the start of the operation still exceeds 30 minutes, the rubber particle-containing thermoplastic resin composition B is passed through the filter to cause aggregation of the rubber particles. Is likely to occur. On the other hand, when the extruder is sized so as to be suitable for the conditions at the start of operation of the extruder or immediately after the start of operation, if it becomes a steady state, more molten resin than it can withstand in the size design will flow into the filter, This is not preferable because the filter will be damaged beyond the filter pressure resistance and the life of the filter may be shortened.

In addition, if the residence time in the filter is to be less than 10 minutes, it is necessary to increase the resin temperature and decrease the resin melt viscosity, but this is not preferable because the resin is thermally decomposed at the high temperature and the film physical properties deteriorate. .

  When the thermoplastic resin composition A not containing rubber particles is continuously switched to the rubber particle-containing thermoplastic resin composition B, the composition of the thermoplastic resin composition A and the rubber particles of the rubber particle-containing thermoplastic resin composition B are changed. The composition of the part to be excluded may be different from each other, but from the viewpoint of compatibility at the time of switching, the composition of the thermoplastic resin composition A and the part of the part excluding the rubber particles of the rubber particle-containing thermoplastic resin composition B The composition is preferably closer, and the composition of the thermoplastic resin composition A and the composition of the rubber particle-containing thermoplastic resin composition B excluding the rubber particles are most preferably the same composition. Here, the composition can be determined by the type and composition ratio of the monomers constituting the resin, and the compounding ratio of the resin and other components.

  When the composition is not close and the compatibility is poor, after the thermoplastic resin composition A not containing rubber particles is switched to the rubber particle-containing thermoplastic resin composition B, the film may become white and cloudy, and transparent It takes time to become. The white and cloudy part cannot be used as an optical film and is wasted.

  By making the composition of the thermoplastic resin composition A and the composition of the rubber particle-containing thermoplastic resin composition B excluding the rubber particles the same composition having excellent compatibility, the thermoplastic resin composition A contains the rubber particles. Production of a rubber particle-containing optical film comprising the rubber particle-containing thermoplastic resin composition B by shortening the time until the film physical properties are stabilized by switching to the thermoplastic resin composition B and reducing waste of the film. Is possible.

  When rubber particles are contained in the thermoplastic resin composition having the same composition, the melt viscosity tends to increase due to the inclusion of the rubber particles. Therefore, when the composition of the thermoplastic resin composition A and the composition of the portion excluding the rubber particles of the rubber particle-containing thermoplastic resin composition B are the same composition, the thermoplastic resin composition containing the rubber particles from the thermoplastic resin composition A The switching to B is a switching from a low viscosity to a high viscosity, so that a switching failure such as a short path hardly occurs and an efficient switching is possible.

  Although the switching method is not particularly limited, for example, it can be easily performed by changing the resin of the resin supply hopper that supplies the pellets to the extruder. Specifically, using a single hopper, the method in which the thermoplastic resin composition A containing the rubber particle-containing thermoplastic resin B is put into the same hopper after the remaining amount of the thermoplastic resin composition A in the hopper is reduced, or using two hoppers. For example, after the outlet of the thermoplastic resin composition A supply hopper is blocked, the outlet of the rubber particle-containing thermoplastic resin composition B supply hopper is opened.

(Molding)
When the thermoplastic resin composition in a molten state that has passed through the filter is formed into a film, it can be formed into a film by discharging it from a T-die. By making the shape of the die outlet appropriate, the molten thermoplastic resin composition can take a film shape. Subsequently, by cooling the thermoplastic resin composition to a temperature below its glass transition temperature by a process of sandwiching and molding the film-like thermoplastic resin composition discharged from the die outlet between an elastic roll and a cast roll, optical A film can be obtained. Moreover, an optical film is acquirable only by making the sheet-like thermoplastic resin composition in a molten state cast on a cast roll, without using an elastic roll. In addition, the said process to shape | mold is a process for smoothing the film surface, and is different from the process for extending | stretching a film.

  Here, the measuring method of the glass transition temperature is as follows. 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. Can be requested.

  The film formed through the process of filtering the thermoplastic resin composition by passing it through a filter is a high-quality optical film having high quality and strength free from convex defects. An optical film having further excellent strength can be obtained by stretching with a stretching machine as necessary.

(Stretching)
After forming the film, it is preferable to further stretch the film to obtain a stretched film. This is because the stretched film can not only increase the in-plane retardation and the thickness direction retardation of the optical film, but also improve the mechanical properties of the film. When the film is stretched, any conventionally known stretching method may be used, and it may be a uniaxially stretched uniaxially stretched film or a biaxially stretched film in which a further stretching process is combined. In particular, sequential biaxial stretching is preferred from the viewpoint of improving the thickness direction retardation and mechanical properties. In addition, sequential biaxial stretching means extending | stretching in 2 steps with respect to the film after shaping | molding.

  In the first-stage stretching method, stretching of 150 to 220% is preferable with respect to the original film length of 100%, and stretching of 160 to 200% is more preferable. If it is less than 150%, sufficient strength cannot be obtained. If it exceeds 220%, the resin is excessively oriented in the stretching direction, and breakage tends to occur during the subsequent second-stage stretching.

  The stretching temperature at the first stage is preferably 0 to + 30 ° C., more preferably +5 to + 20 ° C. with respect to the glass transition temperature of the film measured by DSC. If the temperature is lower than the glass transition temperature, too much tension is applied, breakage occurs during stretching, and the yield is adversely affected. If the temperature exceeds + 30 ° C., sufficient strength cannot be obtained.

  The second stage stretching method is preferably 90 to 110% stretching, more preferably 95 to 105% stretching relative to the first stage stretching. Exceeding the above range causes anisotropy in strength development (when the second stage stretching is large, the second stage direction is strong and the first stage direction is weak. When the second stage stretching is small, 2 The step direction is weak, and the first step direction is weak), and then breakage is likely to occur in the step of winding the film.

  The stretching temperature in the second stage is preferably 0 to + 30 ° C., more preferably +5 to + 25 ° C. with respect to the glass transition temperature of the film measured by DSC. If the temperature is lower than the glass transition temperature, too much tension is applied and breakage tends to occur during stretching, which adversely affects the yield. If the temperature exceeds + 30 ° C., sufficient strength cannot be obtained.

  The thickness of the film after stretching is not particularly limited, but is preferably 10 μm to 60 μm, more preferably 15 μm to 50 μm, and further preferably 15 μm to 40 μm.

(Take-up)
It is preferable to have a step of winding these films after forming the films or further stretching the films.

  The film winding speed is preferably 15 m / min to 80 m / min in a steady state, more preferably 20 m / min to 75 m / min, and even more preferably 30 m / min to 70 m / min. .

  When the above-mentioned biaxial stretching is performed continuously while winding the film, the thermoplastic resin composition A is switched to the rubber particle-containing thermoplastic resin composition B by winding the film formed from the thermoplastic resin composition A. It is preferable to carry out so as not to lower the film winding speed and the discharge amount after the taking speed has reached a steady state, in particular, after the steady state has been reached. High speed, such as the speed at which the film in the steady state is wound up, is difficult to handle and is likely to cause manufacturing trouble. If the discharge rate is reduced before and after switching to the rubber particle-containing thermoplastic resin composition B, aggregation occurs. This is because it tends to cause a convex defect.

(Thermoplastic resin composition A containing no rubber particles)
The thermoplastic resin composition A used in the present invention is not particularly limited as long as it is a thermoplastic resin composition 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, The thermoplastic resin composition which consists of polyphenylene oxide resin etc. is mentioned. Among these, an acrylic resin is particularly preferable because it is excellent in transparency and suppresses light loss when used in an optical film.

  Although there is no restriction | limiting in particular as acrylic resin, The methacrylic resin which used methyl methacrylate as a monomer component can be used, and what contained 30-100 weight% of methyl methacrylate is preferable.

  Moreover, a heat resistant acrylic resin can be used. Examples of heat-resistant acrylic resins include acrylic resins in which an N-substituted maleimide compound is copolymerized as a copolymerization component, anhydrous glutaric acid acrylic resins, acrylic resins having a lactone ring structure, and glutarimide acrylic resins. An aromatic vinyl-containing polymer obtained by polymerizing a resin, an acrylic resin containing a hydroxyl group and / or a carboxyl group, an aromatic vinyl monomer and another monomer copolymerizable therewith, or an aromatic ring thereof. Hydrogenated aromatic vinyl-containing polymers obtained by partial or complete hydrogenation (for example, aromatics of styrenic polymers obtained by polymerizing styrene monomers and other monomers copolymerizable therewith) Partially hydrogenated styrene polymers obtained by partial hydrogenation of rings), acrylic polymers containing cyclic acid anhydride repeating units, etc. Door can be. Of the heat-resistant acrylic resins, glutarimide acrylic resins can be more preferably used from the viewpoint of excellent heat resistance and optical properties.

  The glutarimide acrylic resin will be described in detail below.

（式中、Ｒ^１およびＲ^２は、それぞれ独立して、水素または炭素数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、 Specific examples of the glutarimide acrylic resin include the following general formula (1).

(Wherein R ¹ and R ² are each independently hydrogen 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 cycloalkyl having 3 to 12 carbon atoms. 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)

（式中、Ｒ^４およびＲ^５は、それぞれ独立して、水素または炭素数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。なお、本願において「（メタ）アクリル」とは、「メタクリルまたはアクリル」を指すものとする。）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。

(In the formula, R ⁴ and R ⁵ are each independently hydrogen or an alkyl group having 1 to 8 carbon atoms, and R ⁶ is an alkyl group having 1 to 18 carbon atoms or a cycloalkyl having 3 to 12 carbon atoms. Or a substituent containing an aromatic ring having 5 to 15 carbon atoms.)
(Hereinafter also referred to as “(meth) acrylic acid ester unit”. In the present application, “(meth) acrylic” means “methacrylic or acrylic”). An acrylic resin can be suitably used.

  Moreover, the said glutarimide acrylic resin is the following general formula (3) as needed.

（式中、Ｒ^７は、水素または炭素数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。

(Wherein R ⁷ is hydrogen 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 hydrogen or a methyl group, R ³ is preferably hydrogen, a methyl group, a butyl group, or a cyclohexyl group, and R ¹ is More preferably, it is a methyl group, R ² is hydrogen, and R ³ is 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.

  The glutarimide unit can be formed by imidizing the (meth) acrylic acid ester unit represented by the general formula (2). 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 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 . The content of the glutarimide unit is preferably 1% by weight or more of the glutarimide acrylic resin, more preferably 1% to 95% by weight, and more preferably 2% to 90% by weight. More preferred is 3 to 80% by weight.

  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. There is nothing 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.

The content of the glutarimide unit is calculated by the following method.
^{Using 1} H-NMR BRUKER Avance III (400 MHz), ¹ H-NMR measurement of the resin is performed to determine the content (mol%) of each monomer unit such as glutarimide unit or ester unit in the resin, and the content The amount (mol%) is converted to the content (% by weight) using the molecular weight of each monomer unit.

For example, in the case of a resin comprising a glutarimide unit in which R ³ is a methyl group in the above general formula (1) and a methyl methacrylate unit, it is derived from the O-CH ₃ proton of methyl methacrylate appearing in the vicinity of 3.5 to 3.8 ppm. From the peak area a and the peak area b derived from the N—CH ₃ proton of glutarimide that appears in the vicinity of 3.0 to 3.3 ppm, the content (% by weight) of the glutarimide unit is obtained by the following formula. Can do.
[Methyl methacrylate unit content A (mol%)] = 100 × a / (a + b)
[Content B (glut%) of glutarimide unit] = 100 × b / (a + b)
[Content of glutarimide unit (% by weight)] = 100 × (b × (molecular weight of glutarimide unit)) / (a × (molecular weight of methyl methacrylate unit) + b × (molecular weight of glutarimide unit))

  In addition, also when a unit other than the above is included as a monomer unit, content (weight%) of a glutarimide unit can be calculated | required similarly from content (mol%) and molecular weight of each monomer unit in resin.

  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 zero. When the aromatic vinyl unit represented by the general formula (3) is included, it is preferably 10% by weight or more, preferably 10% by weight to 40% by weight, based on the total repeating unit of the glutarimide acrylic resin. More preferably, it is more preferable to set it as 15 to 30 weight%, and it is especially preferable to set it as 15 to 25 weight%.

  If the content of the aromatic vinyl unit is within the above range, the resulting glutarimide acrylic resin will not have insufficient heat resistance, and the mechanical strength during film processing will not 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.

  These other units may be those introduced by copolymerizing the monomer constituting the unit with a resin that is a raw material for producing a glutarimide acrylic resin. Further, when the imidization reaction is performed, these other units may be by-produced and included 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, moldability will not fall or the mechanical strength at the time of film processing will not be insufficient. 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 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 mentioned.

  Specifically, for example, as a method for producing an imide resin, a first-stage reaction in which an acrylic resin and an imidizing agent are treated with a first extruder, and a reaction in the first extruder with a second extruder. An example of the reaction is a second-stage reaction in which the product is further treated with an esterifying agent.

  A tandem type extruder having a first extruder, a second extruder, and a component connecting a resin discharge port of the first extruder and a raw material supply port of the second extruder can be used.

  The internal pressure of the part connecting the resin discharge port of the first extruder and the raw material supply port of the second extruder is preferably 5 MPa or more and 50 MPa or less.

  Examples of imidizing agents include amines containing aliphatic hydrocarbon groups such as methylamine, ethylamine, n-propylamine, i-propylamine, n-butylamine, i-butylamine, tert-butylamine, n-hexylamine, and aniline. Aromatic hydrocarbon group-containing amines such as benzylamine, toluidine, and trichloroaniline, alicyclic hydrocarbon group-containing amines such as cyclohexylamine, and ammonia. In addition, urea compounds such as urea, 1,3-dimethylurea, 1,3-diethylurea, and 1,3-dipropylurea that generate these amines by heating can also be used. Of these imidizing agents, methylamine, ammonia, and cyclohexylamine are preferable from the viewpoint of cost and physical properties, and methylamine is particularly preferable.

  The addition amount of the imidizing agent can be appropriately determined depending on the imidization rate for expressing necessary physical properties. For example, it is 1 to 100 parts by weight with respect to 100 parts by weight of the main raw material such as acrylic resin.

  In the tandem type reaction extruder, the amount of the imidizing agent added is preferably 1 to 70 parts by weight, more preferably 1 to 40 parts by weight with respect to 100 parts by weight of the main raw material such as acrylic resin.

Examples of the esterifying agent include dimethyl carbonate, 2,2-dimethoxypropane, dimethyl sulfoxide, triethyl orthoformate, trimethyl orthoacetate, trimethyl orthoformate, diphenyl carbonate, dimethyl sulfate, methyl toluene sulfonate, methyl trifluoromethyl sulfonate. , Methyl acetate, methanol, ethanol, methyl isocyanate, p-chlorophenyl isocyanate, dimethylcarbodiimide, dimethyl-t-butylsilyl chloride, isopropenyl acetate, dimethylurea, tetramethylammonium hydroxide, dimethyldiethoxysilane, tetra-N-butoxy Silane, dimethyl (trimethylsilane) phosphite, trimethyl phosphite Trimethyl phosphate, tricresyl phosphate, diazomethane, ethylene oxide, propylene oxide, cyclohexene oxide, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, benzyl glycidyl ether.

The addition amount of the esterifying agent is determined by the ratio of the acid component in the resin for expressing necessary physical properties. Preferably, it is 1 to 100 parts by weight with respect to 100 parts by weight of the imide resin intermediate 1.

When the imide resin intermediate 1 is treated with an esterifying agent and / or heat-treated, or for the imide resin intermediate 2, generally used catalysts, antioxidants, heat stabilizers, plasticizers, lubricants, UV absorption An agent, an antistatic agent, a coloring agent, an anti-shrinkage agent and the like may be added as long as the object of the present invention is not impaired.

(Rubber particle-containing thermoplastic resin composition B)
Hereinafter, the rubber particle-containing thermoplastic resin composition B will be specifically described.

  The rubber particles may be a polymer having a glass transition temperature of less than 20 ° C., and examples thereof include a butadiene-based crosslinked polymer, a (meth) acrylic crosslinked polymer, and an organosiloxane-based crosslinked polymer. Among these, a (meth) acrylic crosslinked polymer (acrylic rubbery polymer) is particularly preferable in terms of weather resistance (light resistance) and transparency of the film.

  Examples of the acrylic rubber-like polymer include ABS resin rubber and ASA resin rubber. From the viewpoint of transparency and the like, an acrylic graft copolymer (hereinafter referred to as an acrylic ester rubber-like polymer) shown below is included. And simply referred to as “acrylic graft copolymer”).

The acrylic graft copolymer can be obtained by polymerizing a monomer mixture containing methacrylic acid ester as a main component in the presence of an acrylic ester rubbery polymer.
The acrylic ester rubber-like polymer is a rubber-like polymer mainly composed of an acrylic ester. Specifically, 50 to 100% by weight of an acrylic ester and other vinyl monomers that can be copolymerized are used. 0.05 to 10 polyfunctional monomer having 2 or more non-conjugated reactive double bonds per molecule with respect to 100 parts by weight of the monomer or monomer mixture consisting of 50 to 0% by weight Those obtained by polymerizing parts by weight are preferred. The entire monomer mixture may be mixed and polymerized, or the monomer composition may be used in two or more stages while changing the composition of the monomer for each reaction stage.

  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, propyl acrylate, n-butyl acrylate, 2-butyl acrylate, isobutyl acrylate, benzyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, etc. These monomers may be used in combination of two or more.

  Of the monomer mixture used for polymerization to obtain an acrylate ester rubbery polymer, the amount of the acrylate ester is preferably 50% by weight to 100% by weight in 100% by weight of the monomer mixture, and 60% by weight. % To 99% by weight is more preferable, 70% to 99% by weight is more preferable, and 80% to 99% by weight is most preferable. 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 that can be copolymerized, (meth) acrylic acid esters are particularly preferred from the viewpoint of weather resistance and transparency. For example, methyl methacrylate, ethyl methacrylate, propyl methacrylate, and methacrylate n -Butyl, 2-butyl methacrylate, isobutyl methacrylate, benzyl methacrylate, cyclohexyl methacrylate, phenoxyethyl (meth) acrylate, phenyl (meth) acrylate, and the like. Aromatic vinyls and derivatives thereof, and vinyl cyanides are also preferable, and examples thereof 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.

  The polyfunctional monomer may be a commonly used one such as allyl methacrylate, allyl acrylate, triallyl cyanurate, triallyl isocyanurate, diallyl phthalate, diallyl malate, divinyl adipate, divinyl benzene, ethylene glycol dimethacrylate, Diethylene glycol methacrylate, triethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, tetromethylol methane tetramethacrylate, dipropylene glycol dimethacrylate and acrylates thereof can be used. Two or more of these polyfunctional monomers may be used.

  Among the monomer mixture used for the polymerization for obtaining an acrylic ester rubbery polymer, the amount of the polyfunctional monomer is 0.05 to 10 parts per 100 parts by weight of the total amount of the monomer mixture. Part by weight is preferable, and 0.1 to 5 parts by weight is more preferable. If the addition amount of the polyfunctional monomer is less than 0.05 parts by weight, there is a tendency that a crosslinked product cannot be formed, and even if it exceeds 10 parts by weight, the crack resistance of the film tends to be lowered.

  The volume average particle diameter of the rubber particles is preferably 20 to 450 nm, more preferably 20 to 300 nm, still more preferably 20 to 150 nm, and most preferably 30 to 80 nm. If it is less than 20 nm, crack resistance may deteriorate. On the other hand, if it exceeds 450 nm, the transparency may decrease. The volume average particle diameter can be measured by a dynamic scattering method, for example, by using MICROTRAC UPA150 (manufactured by Nikkiso Co., Ltd.).

  The acrylic graft copolymer is a monomer mixture 95 containing a methacrylic ester as a main component in the presence of 5 to 90 parts by weight (more preferably, 5 to 75 parts by weight) of an acrylate ester rubbery polymer. Those obtained by copolymerizing ˜25 parts by weight are preferred. The copolymerization may be performed in one stage or in multiple stages. In the latter case, the composition of the monomer mixture added at each stage or the reaction conditions at each stage can be appropriately changed. The methacrylic acid ester in the acrylic graft copolymer is preferably 50% by weight or more. If it is 50% by weight or less, the hardness and rigidity of the resulting film tend to decrease. As the monomer used for the graft copolymerization, the above-mentioned methacrylic acid esters, acrylic acid esters, and vinyl monomers copolymerizable therewith can be used in the same manner, and methacrylic acid esters and acrylic acid esters are preferred. used. 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 excellent 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”). .) Are preferred, and specific examples include benzyl (meth) acrylate, dicyclopentanyl (meth) acrylate, and phenoxyethyl (meth) acrylate. The amount used is 1 to 100% by weight in 100% by weight of the total amount of the monomer mixture (the total amount of the ring structure-containing (meth) acrylic monomer and other monofunctional monomers copolymerizable therewith). 5 to 70% by weight is more preferable, and 5 to 50% by weight is most preferable. As the other monofunctional monomer copolymerizable therewith, the above-mentioned methacrylic acid ester, acrylic acid ester, and other copolymerizable vinyl monomers can be used in the same manner.

  The graft ratio with respect to the acrylic ester rubbery polymer is preferably 10 to 250%, more preferably 40 to 230%, and most preferably 60 to 220%. If the graft ratio is less than 10%, the acrylic graft copolymer tends to aggregate in the molded article, 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 is 250% or more, the melt viscosity at the time of molding, for example, at the time of film molding tends to be high, and the moldability of the film tends to decrease. The calculation formula will be described in the section of the embodiment.

  The graft ratio is a weight ratio of the graft component in the acrylic graft copolymer, and is measured by the following method.

  2 g of the obtained acrylic graft copolymer was dissolved in 50 ml of methyl ethyl ketone, and centrifuged 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). And soluble components (set a total of three centrifuge operations). The obtained insoluble matter is calculated by the following formula as an acrylic ester graft polymer.

  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 may further have a hard polymer layer or a cross-linked polymer layer in addition to the polymer layer composed of the monomer mainly composed of the above-mentioned methacrylic acid ester.

  The acrylic graft copolymer can be produced by a general emulsion polymerization method. Specifically, a method of continuously polymerizing a monomer mixture 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 acrylate 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 polymerization heat generated in the reactor In order to ensure the amount of heat removal, 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 can 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 polymerization initiators in combination with reducing agents such as sodium sulfite, sodium thiosulfate, sodium formaldehyde sulfoxylate, ascorbic acid, ferrous sulfate and ethylenediaminetetraacetic acid-2-sodium complex. May be used.

  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 particular limitation on the emulsifier used in the emulsion polymerization method, and any emulsifier for ordinary 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 amount of the emulsifier used is preferably 0.05 parts by weight or more and 10 parts by weight or less, and 0.1 parts by weight or more and 1.0 parts by weight or less with respect to 100 parts by weight of the whole monomer component of the acrylic graft copolymer. The following is more preferable. If the amount is less than 0.05 parts by weight, the copolymer particle system tends to be too large. If the amount is more than 10 parts by weight, the copolymer particle system tends to be too small, and the particle size distribution tends to deteriorate. .

  The rubber particle-containing thermoplastic resin composition B is a mixture of rubber particles and the thermoplastic resin composition A, and includes one or more kinds of (meth) acrylic crosslinked polymers (acrylic rubbery polymers) and one or more kinds. It is preferable that it is a mixed composition with acrylic resin.

  The acrylic rubbery polymer is preferably blended so as to be contained in an amount of 1 to 60 parts by weight, more preferably 1 to 30 parts by weight, and 1 to 25 parts by weight in 100 parts by weight of the rubber particle-containing thermoplastic resin composition B. Part is more preferable. If it is less than 1 part by weight, the crack resistance and vacuum formability of the film may deteriorate, the photoelastic constant may increase, and optical isotropy may deteriorate. On the other hand, when it exceeds 60 parts by weight, the heat resistance, surface hardness, transparency, and bending whitening resistance of the film tend to deteriorate.

  The acrylic rubber-like polymer and acrylic resin may be mixed directly during film production. Once the acrylic rubber-like polymer and methacrylic resin are mixed into pellets, the film is produced again. May be implemented.

By using the rubber particle-containing thermoplastic resin composition B as a material for the optical film, the rubber particles may be present on the film surface, which may impair the surface smoothness of the film. In such a case, it is expected that the rubber particles are pushed into the film and the surface smoothness of the film is improved by performing sandwich molding after melt extrusion. However, when the compatibility between the rubber particles and the matrix resin is low, the rubber particles are likely to aggregate in the film, and as a result, the unevenness of the film surface may increase. As a result of not being able to reduce fine irregularities on the film surface, there was an inconvenience that surface irregularities that are undesirable for an optical film were observed.
However, according to the present invention, even if the thermoplastic resin composition contains rubber particles, and the rubber particles have low compatibility with the matrix resin, the fine unevenness of the surface is reduced, and the surface unevenness is reduced. The effect of reducing can be achieved.

(Optional component)
In the thermoplastic resin composition used in the present invention, an antioxidant, an ultraviolet absorber, an ultraviolet stabilizer, etc. for improving stability to heat and light may be added alone or in combination of two or more.

(Use)
The rubber particle-containing optical film produced in the present invention is a member used in a display device such as a liquid crystal display device, such as a polarizing plate protective film, a retardation film, a brightness enhancement film, a liquid crystal substrate, a light diffusion sheet, a prism sheet, etc. Can be used. Especially, it is suitable for a polarizing plate protective film and retardation film.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, this invention is not limited to these Examples. In addition, the measuring method of each physical property measured in the following examples and comparative examples is as follows.

(Residence time in filter)
At the start of operation of the extruder, after the rotation of the gear pump installed on the downstream side of the extruder (when molten resin starts to be supplied from the gear pump to the filter), the resin pressure gauge installed in the flow path downstream of the gear pump and upstream of the filter The time until the value increased and reached a steady value was measured. The residence time at the steady discharge amount was calculated from the time measured at the discharge amount at the start of operation and the ratio of the discharge amount at the start of operation and the steady discharge amount.

(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.

(Convex defect evaluation)
The obtained film was cut into A4 size (210 mm x 297 mm), marked with defects by visual inspection, and then observed with a KEYENCE digital microscope VHX1000 at 100 times. The convex defect of 20 micrometers or more was extracted and the number was measured.

(transparency)
The obtained film was cut out into the total width in the film width direction × 20 cm in the film flow direction, and the transparency of the film was visually confirmed by visual inspection. If there was a cloudy part even in part in the width direction, it was marked as x, and if it was transparent over the entire width, it was marked as ○.

(Production Example 1)
<Manufacture of glutarimide acrylic resin (A1)>
A glutarimide acrylic resin (A1) was produced using polymethyl methacrylate as the raw material resin and monomethylamine as the 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 component 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 is 280 ° C., the screw rotation speed is 55 rpm, the raw material resin supply amount is 150 kg / hour, and the addition amount of monomethylamine is 2.0 parts by weight with respect to 100 parts by weight of the raw material resin. did. 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, the barrel temperature of the extruder was 260 ° C., the screw rotation speed was 55 rpm, and the amount of dimethyl carbonate added was 3.2 parts by weight with respect to 100 parts by weight of the raw material 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 a glutarimide acrylic resin (A1).

  The obtained glutarimide acrylic resin (A1) is an acrylic resin obtained by copolymerizing a glutamylimide unit and a (meth) acrylic acid ester unit.

(Production Example 2)
<Manufacture of rubber particles>
The following substances were charged into an 8 L polymerization apparatus equipped with a stirrer.
Deionized water 200 parts by weight Polyoxyethylene lauryl ether sodium phosphate 0.05 parts by weight Sodium formaldehyde sulfoxylate 0.11 parts by weight Ethylenediaminetetraacetic acid-2-sodium 0.004 parts by weight Ferrous sulfate 0. 001 parts by weight

  After sufficiently replacing the inside of the polymerization machine with nitrogen gas to make it substantially free of oxygen, the internal temperature was set to 40 ° C., and the raw material mixture of acrylic rubber particles (C-1) (butyl acrylate 90%, methyl methacrylate) 45.491 parts of allyl methacrylate and 0.441 parts by weight of cumene hydroperoxide) were continuously added over 225 minutes to 45 parts by weight of 10% monofunctional monomer. (C-1) 20 minutes, 40 minutes and 60 minutes after the start of addition, sodium polyoxyethylene lauryl ether phosphate (polyoxyethylene lauryl ether phosphate (trade name: Phosphanol RD, manufactured by Toho Chemical Industry Co., Ltd.) -510Y sodium salt) was added in an amount of 0.2 parts by weight to the polymerization machine, and after the addition, the polymerization was further continued for 0.5 hours to obtain acrylic rubber particles (polymer of (C-1)). The polymerization conversion rate was 98.6%.

  Thereafter, the internal temperature was set to 60 ° C., and 0.2 part by weight of sodium formaldehyde sulfoxylate was charged, and then the raw material mixture (C-2) of the hard polymer layer (methyl methacrylate 57.8%, acrylic acid 55% by weight of monofunctional monomer composed of 4% butyl and 38.2% benzyl methacrylate, 0.3 part by weight of t-dodecyl mercaptan, 0.254 part by weight of cumene hydroperoxide) 55.554 parts by weight Was continuously added over 210 minutes, and the polymerization was further continued for 1 hour to obtain a graft copolymer latex. 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 rubber particles (C1) of a white powdered graft copolymer.

  The average particle size of the rubber particles (C1) of the graft copolymer was 121 nm. The graft ratio of the graft copolymer was 56%.

(Production Example 3)
<Production of rubber particle-containing thermoplastic resin composition B pellet>
Using a single screw extruder using a full flight screw with a diameter of 40 mm, setting temperature of the temperature adjustment zone of the extruder is 255 ° C., screw rotation speed is 52 rpm, 95 parts by weight of glutarimide acrylic resin (A1), and white A mixture of 5 parts by weight of powder particles of the graft copolymer rubber particles (C1) was supplied at a rate of 10 kg / hr. The resin that emerged as a strand from a die provided at the exit of the extruder was cooled in a water tank, and a rubber particle-containing thermoplastic resin composition (B1) pelletized with a pelletizer was obtained.

(Production Example 4)
<Manufacture of thermoplastic resin composition A pellet>
A single screw extruder using a full flight screw with a diameter of 40 mm was used. The temperature adjustment zone of the extruder was set to 255 ° C., the screw rotation speed was 52 rpm, and only glutarimide acrylic resin (A1) was 10 kg / hr. Supplied in proportion. Resin that emerged as a strand from a die provided at the exit of the extruder was cooled in a water tank, and a thermoplastic resin composition (A1) pelletized with a pelletizer was obtained.

Example 1
After using the thermoplastic resin composition (A1) pellets (glass transition temperature Tg = 122 ° C.) obtained in Production Example 4 as the thermoplastic resin composition A and drying it at 80 ° C. for 4 hours in a dryer. , And supplied to a φ65 mm single screw extruder. At the exit of the extruder, a screen mesh was placed in the order of # 60, # 100, # 60 from the extruder side in order to remove coarse foreign matters contained in the composition. The resin was heated and melted so that the resin temperature became 260 ° C. at the exit of the extruder, passed through a leaf disk filter (cut of 5 μm openings) as a filter through a gear pump, and then the molten resin was extruded into a T-die. With respect to the steady design discharge rate of 100 kg / hr, the discharge rate at the start of operation was 50 kg / hr, 50% of the steady discharge rate, and the residence time in the filter was 40 minutes.

  After cooling and solidifying this, it was taken up by a take-up roll to obtain a raw material having a thickness of 140 μm. The film winding speed at this time was 10 m / min. The obtained raw fabric is continuously stretched twice in the longitudinal direction with a roll longitudinal stretching machine under the condition of Tg + 10 ° C., and then continuously stretched twice in the lateral direction with a clip-type tenter lateral stretching machine, It extended | stretched on the conditions of Tg + 10 degreeC. This was continuously slit at both ends, and then taken up by a take-up roll to form a film having a thickness of 40 μm on the take-up core. Thereafter, the discharge amount and the film winding speed were gradually increased to obtain a steady discharge amount. At this time, the residence time in the filter was 20 minutes, and the film winding speed was 20 m / min.

  Thereafter, pellets of the rubber particle-containing thermoplastic resin composition (B1) obtained in Production Example 3 from the extruder hopper without dropping the discharge amount (at this time, containing the thermoplastic resin composition (A1) and the rubber particles) The portion of the thermoplastic resin composition (B1) excluding the rubber particles is the same composition) and was continuously switched. Switching was started 60 minutes after the start of operation of the extruder. Thereafter, the film was sampled from the start of switching over time until 9 hours passed, and convex defects and transparency were evaluated. The results are as shown in Table 1. From the start of operation until 9 hours after the start of switching, no convex defects were generated and a good transparency film was obtained without loss.

(Example 2)
A film was obtained in the same manner as in Example 1 except that the glutarimide acrylic resin (A1) was replaced with polymethyl methacrylate resin (PMMA), and convex defects and transparency were evaluated. As shown in Table 1, no convex defects occurred from the start of operation until 9 hours after the start of switching, but part of the film was clouded until 1 hour after the start of switching. That is, in this example, the rubber particle-containing optical film comprising the target rubber particle-containing thermoplastic resin composition (B1) can be obtained from 3 hours after switching.

Example 3
A film was obtained in the same manner as in Example 1 except that the discharge amount at the start of operation was 33% of the steady discharge amount, and convex defects and transparency were evaluated. The residence time in the filter at the start of operation was 60 minutes, and the film winding speed was 6.6 m / min. As a result, as shown in Table 1, there was no problem in the transparency of the film from the start of operation until 9 hours after the start of switching, but a convex defect occurred in the film until 1 hour after the start of switching. That is, in this example, the rubber particle-containing optical film comprising the target rubber particle-containing thermoplastic resin composition (B1) can be obtained from 3 hours after switching.

(Comparative Example 1)
The rubber particle-containing thermoplastic resin composition (B1) obtained in Production Example 3 was used both at the start of operation and after reaching a steady state, and the same procedure as in Example 1 was performed except that the switching was not performed. As shown in Table 1, there was no problem in the transparency of the film from the start of operation until 9 hours after the start of operation, but many convex defects occurred until the time after 3 hours of operation, and 9 hours after the start of operation. It did not disappear completely even at that time. That is, in this example, it is necessary to take the rubber particle-containing optical film made of the desired rubber particle-containing thermoplastic resin composition (B1) after at least 9 hours of operation.

(Comparative Example 2)
The leaf disk filter size, which is a filter, is designed to be about twice that of Example 1 (double the number of media) so that the residence time in the filter is 40 minutes even after the steady state is reached, and the discharge amount at the start of operation. Was performed in the same manner as in Example 1 except that 66% of the steady discharge amount was set. The film winding speed is 10 m / min as in the example. As shown in Table 1, there was no problem in the transparency of the film from the start of operation until 9 hours after the start of switching, but many convex defects occurred from the start of operation. It increased. That is, in this example, it was impossible to obtain a rubber particle-containing optical film comprising the desired rubber particle-containing thermoplastic resin composition (B1).

(Comparative Example 3)
The same procedure as in Example 1 was performed except that the thermoplastic resin composition (A1) obtained in Production Example 4 was used at the start of operation and the resin was not changed. As a result, as shown in Table 1, since the rubber particle-containing thermoplastic resin composition B was not used, there was no problem with the convex defects and the transparency of the film.

Claims (5)

Supplying a thermoplastic resin composition to the extruder;
A step of bringing the thermoplastic resin composition into a molten state by the extruder;
Filtering the thermoplastic resin composition in a molten state in the molten state by passing the thermoplastic resin composition through a filter;
Forming the thermoplastic resin composition that has passed through the filter into a film,
In the supplying step, at the start of operation of the extruder, the thermoplastic resin composition is a thermoplastic resin composition A containing no rubber particles,
In the step of filtering, when the residence time in the filter of the thermoplastic resin composition A is 10 to 30 minutes,
Production of a rubber particle-containing optical film, wherein the thermoplastic composition supplied to the extruder is switched from a thermoplastic resin composition A not containing the rubber particles to a rubber particle-containing thermoplastic resin composition B. Method.   The composition of the thermoplastic resin composition A not containing the rubber particles and the composition of the portion excluding the rubber particles of the rubber particle-containing thermoplastic resin composition B are the same. Of producing an optical film containing rubber particles.   The method for producing a rubber particle-containing optical film according to claim 1 or 2, wherein a discharge amount at the start of operation of the extruder is 30 to 90% with respect to a steady discharge amount. Biaxially stretching the film formed by the forming step;
Winding the film,
After the winding speed of the film formed of the thermoplastic resin composition A containing no rubber particles is in a steady state,
The thermoplastic resin composition supplied to the extruder is switched from the thermoplastic resin composition A not containing the rubber particles to the rubber particle-containing thermoplastic resin composition B. The manufacturing method of the rubber particle containing optical film as described in any one.   The method for producing a rubber particle-containing optical film according to any one of claims 1 to 4, wherein the thermoplastic resin contained in the thermoplastic resin composition is an acrylic resin.