JP2016221809A - Method for producing film, film production device and uniaxial drawn film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a film in which, upon drawing to the uniaxial direction, e.g., upon roll longitudinal drawing for a thermoplastic acrylic resin, in which thickness unevenness is reduced, wrinkles are hard to occur, and appearance is satisfactory.SOLUTION: Provided is a method for producing a film comprising a drawing step of drawing a raw fabric film including a thermoplastic resin to a uniaxial direction, and is characterized in that, in the drawing step, a film elastic modulus in the whole of the film width in the vertical direction to the uniaxial direction is reduced, and thereafter, the film elastic modulus in the film periphery part in the vertical direction, or, in the drawing step, the whole of the film width in the vertical direction to the uniaxial direction is heated, and, provided that the film temperature in the peripheral part of the film is defined as Te, the above temperature Tc and Te satisfy Te-Tc>0°C.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a film manufacturing method, a film manufacturing apparatus, and a uniaxially stretched film.

  Optical films represented by polarizer protective films for protecting polarizers and film substrates for liquid crystal display devices have excellent mechanical strength, appearance, and transparency, and have high retardation accuracy and thickness accuracy. Is required.

  Examples of a method for producing such a film include a method for obtaining the above-mentioned film by biaxially stretching a film original obtained by a melt extrusion method or the like. In this case, the biaxial stretching is generally sequential biaxial stretching composed of longitudinal and lateral sequential stretching. Here, a roll longitudinal stretching method is used as the first longitudinal stretching method in sequential biaxial stretching. A method has been reported for easily producing a film having a beautiful appearance without scratching the film by roll stretching, which is a method of stretching the film in the advancing direction while heating it to a predetermined temperature with a low peripheral speed roll and a high peripheral speed roll in close proximity. (See Patent Documents 1 and 2).

JP-A-11-170353 JP2008-307888

  However, according to the study of the present inventor, a neck-in occurs at the time of stretching, which causes a problem that the end portion of the film is thicker than the center portion, and the thickness accuracy in the width direction is deteriorated. In particular, this tendency becomes conspicuous when the magnification is high, and when the magnification is 2.0 times or more, the thin central portion does not come into contact with the transport roll and floats, resulting in significant wrinkling in the central portion. There was a problem.

  In view of the above-described situation, the present invention has a small thickness unevenness in a direction perpendicular to the uniaxial direction (hereinafter also referred to as a width direction) during stretching in a uniaxial direction such as during roll longitudinal stretching, and wrinkles caused by the thickness unevenness. The object is to obtain a film that does not easily occur.

Therefore, as a result of intensive studies by the inventor, the present invention has been achieved. That is, the present invention provides the following.
(I) A method for producing a film comprising a stretching step of stretching a raw film containing a thermoplastic resin in a uniaxial direction,
In the stretching step, after reducing the film elastic modulus in the entire film width in the vertical direction with respect to the uniaxial direction, further reducing the film elastic modulus in the peripheral edge of the film in the vertical direction,
The method for producing a film, wherein the film peripheral edge is a region in which the distance from both extreme ends of the film in the vertical direction is 5% or more and 30% or less, respectively, when the film width is 100%.
(Ii) A method for producing a film comprising a stretching step of stretching a raw film containing a thermoplastic resin in a uniaxial direction,
In the stretching step, the entire film width in the vertical direction with respect to the uniaxial direction is heated, the film temperature at the center of the film width is set to Tc, the film peripheral edge in the vertical direction is heated, and the film peripheral edge The film temperature is Te,
The film peripheral portion is a region in which the distance from both end portions of the film in the vertical direction is 5% or more and 30% or less, respectively, when the film width is 100%.
The temperatures Tc and Te are represented by the following formula (1):
Te-Tc> 0 ° C. (1)
The film manufacturing method characterized by satisfy | filling.
(Iii) Stretching in the stretching step is performed while transporting the original film in the uniaxial direction.
The method for producing a film according to (ii), wherein a second heating means for heating the peripheral edge of the film is disposed downstream of the first heating means for heating the entire film width in the film transport direction.
(Iv) The method for producing a film according to (ii) or (iii), wherein the heating of the entire film width and the heating of the peripheral edge of the film are performed by a radiation heating device.
(V) The method for producing a film according to any one of (i) to (iv), wherein the draw ratio is from 1.1 times to 3.0 times.
(Vi) Stretching in the stretching step is performed while sandwiching the original film with a pair of sandwiching portions that are spaced apart in the uniaxial direction.
When the width of the raw film is w and the distance between the pair of sandwiching portions is L, L / w is 0.1 or more and 2.0 or less, (i) to (v) The manufacturing method of the film as described in any one.
(Vii) The method for producing a film according to any one of (i) to (vi), wherein the width of the raw film is 900 mm or more and 2000 mm or less.
(Viii) stretching means for stretching a raw film containing a thermoplastic resin in a uniaxial direction;
First elastic modulus lowering means for reducing the film elastic modulus in the entire film width in the direction perpendicular to the uniaxial direction;
Second elastic modulus lowering means for further reducing the film elastic modulus at the film peripheral edge in the vertical direction after the elastic modulus lowering by the first elastic modulus lowering means;
A film manufacturing apparatus comprising:
The said film peripheral part is an area | region where the distance from the film both ends in the said perpendicular direction is 5% or more and 30% or less, respectively, when the said film width is 100%.
(Ix) Stretching means for stretching a raw film containing a thermoplastic resin in a uniaxial direction;
A first heating means that heats the entire film width in the direction perpendicular to the uniaxial direction and sets the film temperature at the center of the film width as Tc;
After the heating by the first heating means, the second heating means for heating the film peripheral edge in the vertical direction and setting the film temperature at the film peripheral edge to Te,
A film manufacturing apparatus comprising:
The film peripheral portion is a region in which the distance from both end portions of the film in the vertical direction is 5% or more and 30% or less, respectively, when the film width is 100%.
The temperatures Tc and Te are represented by the following formula (1):
Te-Tc> 0 ° C. (1)
An apparatus for producing a film characterized by satisfying
(X) A uniaxially stretched film containing a thermoplastic resin, where the film width in the vertical direction with respect to the stretching direction is 100%, and the distance from both ends of the film in the vertical direction is 5%. The average value of the difference of thickness and the film thickness in the said film width center is 10.0 micrometers or less, The uniaxially stretched film characterized by the above-mentioned.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the film with the beautiful external appearance with the favorable thickness precision in the width direction, and being hard to produce a wrinkle can be provided. By the production method of the present invention, a film that can be suitably used in optical applications can be produced.

It is the schematic which shows an example of the roll longitudinal stretch method in the manufacturing method of this invention.

Hereinafter, the production method of the present invention will be described in detail.
The method for producing a film according to the present invention includes, in the first embodiment, a stretching process for stretching a raw film containing a thermoplastic resin in a uniaxial direction.
In the stretching step, after reducing the film elastic modulus in the entire film width in the vertical direction with respect to the uniaxial direction, further reducing the film elastic modulus in the peripheral edge of the film in the vertical direction,
The said film peripheral part is an area | region where the distance from the film both ends in the said perpendicular direction is 5% or more and 30% or less, respectively, when the said film width is 100%.

  By reducing the film elastic modulus as described above, the elastic modulus of the film peripheral portion becomes smaller than that of the film central portion, and there is an effect of promoting stretching of the film peripheral portion. As a result, it is possible to suppress the influence of the thickening of the end due to neck-in and obtain a film having a smaller thickness unevenness in the vertical direction.

  In order to achieve the above effect, it is necessary to further reduce the film elastic modulus at the peripheral edge of the film in the vertical direction after reducing the film elastic modulus in the entire film width in the vertical direction. Even after further reducing the film elastic modulus in the entire film width in the vertical direction after reducing the film elastic modulus at the film peripheral edge in the vertical direction, the decrease in the film elastic modulus in the film peripheral edge is less likely to be sufficient. It is difficult to achieve the above effect. By reducing the film elastic modulus in the entire film width in advance, by reducing the film elastic modulus in the film peripheral edge, the film elastic modulus in the film peripheral edge is likely to be sufficiently reduced, and the above effects are achieved. Easy to achieve. The film elastic modulus can be lowered to a desired value, for example, by heating the film.

  As described above, when the film width is 100%, the peripheral edge of the film is a region in which the distance from both end portions of the film in the vertical direction is 5% or more and 30% or less, respectively. When the distance is smaller than 5%, the effect of reducing the elastic modulus of the peripheral edge portion to promote stretching and reducing the thickness unevenness is not sufficiently obtained. When the distance is larger than 30%, the effect of reducing the elastic modulus of the peripheral portion with respect to the central portion to promote stretching and reduce the thickness unevenness is not sufficiently obtained.

The method for producing a film according to the present invention includes, in the second embodiment, a stretching step of stretching a raw film containing a thermoplastic resin in a uniaxial direction.
In the stretching step, the entire film width in the vertical direction with respect to the uniaxial direction is heated, the film temperature at the center of the film width is set to Tc, the film peripheral edge in the vertical direction is heated, and the film peripheral edge The film temperature is Te,
The film peripheral portion is a region in which the distance from both end portions of the film in the vertical direction is 5% or more and 30% or less, respectively, when the film width is 100%.
The temperatures Tc and Te are represented by the following formula (1):
Te-Tc> 0 ° C. (1)
It is characterized by satisfying.

  Hereinafter, the manufacturing method of the film which concerns on 2nd Embodiment is demonstrated, referring FIG. FIG. 1 is a view showing a roll longitudinal stretching method in the film production method of the present invention. The film before stretching is heated by several preheating rolls 1. Thereafter, the film temperature is further raised to a stretchable temperature range with the roll 2 before stretching, and longitudinal stretching is performed between the roll 2 before stretching at a low peripheral speed and the roll 3 after stretching at a high peripheral speed. Thereafter, the film is cooled and solidified by the cooling roll 4 to obtain a film after longitudinal stretching. In FIG. 1, the arrows indicate the flow direction of the film.

  A heating means is provided between the roll before stretching and the roll after stretching for stretching the film, and the film during stretching is heated. By the means 5 for heating the entire film width, the entire film width can be heated between the rolls during stretching to obtain a desired stretching temperature. Further, the heating means 6 for heating the film peripheral portion can increase the temperature of the film peripheral portion as compared with the film central portion, thereby promoting stretching.

  According to the present invention, the following two conditions must be satisfied in order to obtain a stretched film, particularly a longitudinally stretched film, which is excellent in thickness accuracy in the width direction and hardly wrinkles.

(1) Temperature Tc at the center of the film during stretching and temperature Te at the periphery of the film during stretching
The temperature Tc at the center of the film during stretching is the temperature at which the film temperature at the center of the film width is measured using a radiation non-contact thermometer. In the case of FIG. 1, Tc is a film temperature just below the center point in the width direction / flow direction of the heating means 5 that heats the entire film width, as a temperature measured using a radiation non-contact thermometer. When the film width is 100%, the temperature Te at the peripheral edge of the film during film stretching is the distance in the vertical direction in the region in which the distance from both ends of the film in the vertical direction is 5% or more and 30% or less, respectively. Let the film temperature of a central point be the temperature measured using the radiation non-contact-type thermometer. In the case of FIG. 1, Te is a film temperature just below the center point in the width direction and the flow direction of the heating means 6 for heating the film peripheral edge, and is a temperature measured using a radiation non-contact thermometer. Tc and Te need to satisfy the following relational expression.
Te-Tc> 0 ° C

  According to the above formula, the temperature Te at the peripheral edge of the film during stretching is set higher than the temperature Tc at the center of the film during stretching. The upper limit of the difference is not specifically limited, Preferably it is 40 degrees C or less. The value of Te−Tc is preferably more than 0 ° C. and 40 ° C. or less, more preferably 5 ° C. or more and 30 ° C. or less, and further preferably 10 ° C. or more and 20 ° C. or less.

  By setting the temperature of the film peripheral portion and the temperature of the film central portion so as to satisfy the above relational expression, the elastic modulus of the film peripheral portion becomes smaller than that of the film central portion, and the effect of promoting the stretching of the film peripheral portion There is. As a result, when the temperature of the film peripheral part is made higher than that of the film center part, the influence of the thickening of the peripheral part due to neck-in can be suppressed, and a film with less thickness unevenness in the width direction can be obtained.

  In addition, the deterioration of the thickness nonuniformity in the width direction at the time of extending | stretching originates in the form of the expansion | extension at the time of extending | stretching differing in the center part of a film, and the peripheral part of a film. In the central part of the film, the film is not substantially deformed in the width direction, but is deformed only in the longitudinal direction (tensile direction). On the other hand, since the outermost edge of the film is a free end, the film peripheral edge is stretched while being contracted (necked in) in the width direction during stretching. As a result, the film peripheral portion becomes thicker than the film central portion.

  When the temperature of the film peripheral part is the same as or lower than the temperature of the central part, the elastic modulus of the film peripheral part is higher than that of the central part, and the film peripheral part becomes extremely thick due to the neck-in effect. This results in a letter-shaped thickness profile, resulting in poor thickness accuracy. In addition, when the thickness accuracy is poor, wrinkles are generated in the process of being transported from the roll 4 after stretching onto the cooling roll 4 because only the thick film peripheral edge comes into contact with the roll and floats at the center of the film.

  When the temperature of the film peripheral part is 40 ° C. or less compared to the temperature of the central part, the peripheral part of the film is difficult to soften greatly, and sticking hardly occurs when peeling from the roll after stretching. Is unlikely to occur.

(2) Heating method of film As described above, in order to adjust the temperature Tc at the center of the film during stretching and the temperature Te at the peripheral edge of the film during stretching, the entire film width in the direction perpendicular to the uniaxial direction is heated. Then, after setting the film temperature at the center of the film width to Tc, it is necessary to heat the film peripheral part in the vertical direction to set the film temperature at the film peripheral part to Te, and the device is easy to manufacture. From such a viewpoint, it is preferable to provide means for heating the film peripheral edge on the downstream side of the means for heating the entire film width direction.

  The film temperature is heated to near Tg with respect to the entire width direction by a preheating roll or a roll before stretching. After passing through the roll before stretching, when a heater for heating the peripheral edge is installed on the upstream side of the means for heating the entire film width direction between the stretching rolls, the amount of heat is not sufficient, and Te cannot be raised to a temperature higher than Tc. .

  When the means for heating the peripheral portion is installed downstream of the means for heating the entire film width direction, the means for heating the peripheral portion after heating the entire film width direction to the temperature Tc by the means for heating the entire film width direction. Since the peripheral portion is heated at, Te can necessarily be made larger than Tc. In addition, although the space | interval of the means to heat the whole film width direction and the means to heat a peripheral part is not specifically limited, It is preferable that it is 10 mm-200 mm.

  As described above, when the film width is 100%, the film peripheral edge is a region in which the distance from both endmost portions of the film in the vertical direction is 5% or more and 30%, respectively. When the distance is smaller than 5%, the effect of reducing the elastic modulus of the peripheral edge portion to promote stretching and reducing the thickness unevenness is not sufficiently obtained. When the distance is larger than 30%, the region where the temperature is Te is wide with respect to the film width, and the effect of reducing the elastic modulus of the peripheral portion with respect to the central portion to promote stretching and reducing the thickness unevenness is not sufficiently obtained.

  Furthermore, in the present invention, it is preferable to perform heating of the entire film width and local heating of the peripheral edge of the film by a radiant heating device such as an infrared heater. A radiation heating device such as an infrared heater can efficiently heat the film inside in a short time even when the line speed is high due to the effect of radiation. Moreover, it is possible to control to a desired temperature by changing the distance between the film and the radiation heating device, the output, and the irradiation time of the radiation heating device. As a specific example of the stretching temperature control of the infrared heater, when a short wavelength infrared heater (manufactured by Heraeus: ZKB2400 / 340G) is used, the film temperature is set when the distance between the film and the heater tube is 40 mm and the irradiation time is 0.2 seconds. When the distance between the film and the heater tube is 20 mm and the irradiation time is 0.2 seconds, the film temperature can be increased by about 30 ° C.

  Furthermore, in the present invention, the draw ratio is preferably 1.1 to 3.0 times, more preferably 1.5 to 2.7 times, and more preferably 2.0 to 2. It is still more preferable to make it 4 times or less. When the draw ratio is 1.1 times or more, sufficient mechanical strength in the film longitudinal direction (ie, the drawing direction) is easily imparted. In addition, when the draw ratio is 3.0 times or less, the neck-in amount is difficult to increase, and the peripheral part is hardly extremely thick. Therefore, after reducing the film elastic modulus in the entire film width, the film elasticity in the peripheral part of the film The effect of reducing the uneven thickness in the width direction can be sufficiently exhibited by further reducing the rate or increasing the film peripheral temperature Te as compared with the film central temperature Tc.

Further, in the present invention, the stretching in the stretching step is performed while sandwiching the original film with a pair of sandwiching portions (for example, a pair of stretching rolls) that are spaced apart in the uniaxial direction. W and the distance between the pair of sandwiching portions is L, L / w is preferably 0.1 or more and 2.0 or less, more preferably 0.2 or more and 1.0 or less, More preferably, it is 0.3 or more and 0.5 or less. The definition of the distance L between clamping parts is demonstrated using FIG. In the present invention, for example, the film is conveyed and longitudinally stretched by sandwiching the film with both stretching rolls arranged at regular intervals and a nip roll adjacent to both stretching rolls. At this time, the distance between the sandwiching portions 9 is L. Here, since the stretching roll and the nip roll are arranged so that the film transport path is parallel to the plane including the rotation axis of both stretching rolls, the following relationship is established.
(Distance between nipping parts) = (Distance between roll stretching)
In other words, the distance between the sandwiching portions can be directly changed by changing the distance between the rolls.

  When L / w is 0.1 or more, the peripheral edge portion is hardly excessively thick. Therefore, after reducing the film elastic modulus in the entire film width, the film elastic modulus in the film peripheral edge portion may be further reduced, or the film peripheral edge portion may be reduced. The effect of reducing the thickness unevenness in the width direction can be sufficiently exhibited by increasing the temperature Te compared to the film center temperature Tc. When L / w is 2.0 or less, the neck-in amount is hardly increased, the width yield is hardly deteriorated, the distance between the stretches is not easily lengthened, and the thickness unevenness in the flow direction due to the temperature unevenness between the stretches. It is hard to become a problem.

  Furthermore, in this invention, it is preferable that the width | variety of an original fabric film (film before extending | stretching) shall be 900 mm or more and 2000 mm or less, and it is more preferable to set it as 1000 mm or more and 2000 mm or less.

  In the present invention, the roll stretching machine to be used is composed of a preheating roll 1, stretching rolls 2 and 3, and a cooling roll 4. In order to heat the film, the preheating roll is set at a temperature of 50 ° C. or higher, more preferably a glass transition point or higher. Any roll diameter / number is within the scope of the present invention as long as a sufficient heating time is obtained up to the preheating roll set value. The cooling roll is set below the glass transition point in order to cool the film. Any roll diameter and number are within the scope of the present invention as long as sufficient cooling time can be obtained up to the cooling roll set value. In addition, although it does not specifically limit regarding the draw ratio between each cooling roll, It is preferable that it is 100.01% or more. By setting the draw ratio between the cooling rolls to 100.01% or more, the generation of wrinkles can be more effectively suppressed. The stretching roll is a method in which the film is stretched in the advancing direction while being heated to a predetermined temperature by a low peripheral speed roll and a high peripheral speed roll which are close to each other. The roll longitudinal stretching method is not particularly limited, and examples thereof include one-stage stretching in which stretching is performed with a pair of rolls having different peripheral speed differences, and multi-stage stretching in which stretching is performed with two or more pairs of stretching rolls. The stretching is preferably performed by one-stage stretching.

  For one-stage stretching, for example, a roll before stretching, a nip roll adjacent to the roll after stretching, a method in which the film is in contact with each roll while the film is sandwiched by the nip roll, and between the clamping sections as shown in FIG. In the present invention, the method in which the film does not contact each roll between the clamping parts as shown in the latter, that is, the low peripheral speed roll and the high roll A method is used in which the film is longitudinally stretched without contacting each roll between the film sandwiching portions by the peripheral speed roll. In particular, as shown in FIG. 1, the rotation direction of the pre-stretching roll 2 and the post-stretching roll 3 is such that the plane including the rotation axis of the pre-stretching roll 2 and the post-stretching roll 3 and the film transport surface are parallel. It is preferable to use a stretching method in which the directions are the same.

  Even if it is multistage stretching, it is within the scope of the present invention as long as a set of stretching rolls is configured such that the film does not contact each roll between the sandwiching portions as described above.

  Next, means for heating the entire film width during longitudinal stretching will be described. In the present invention, examples of means for heating the entire film width include contact heating by a roll and non-contact heating by a heater, but heating by an infrared heater which is non-contact is preferable. The infrared heater is not particularly limited, but a heater capable of outputting a short wavelength of a maximum energy wavelength range of 1.2 to 1.7 μm and an output of 7.0 W or more per 1 mm width is preferable. Since the temperature of the coil in the heater tube is as high as 1000 ° C. or higher, the heater unit is preferably provided with a cooling mechanism by air cooling or water cooling. In particular, from the viewpoint of thickness accuracy, a water cooling mechanism that does not affect the film conveyance is preferable.

  The size of the infrared heater is not particularly limited, but it is sufficiently longer than the film width W so that the entire film width can be irradiated in the width direction, and sufficient irradiation time can be secured even at a high line speed in the flow direction. It is preferable to use a heater having a length (number). In particular, the irradiation time T is expressed by T = 2 × Lh / (V1 + V2) when the length Lh in the flow direction of the heater, the roll peripheral speed V1 before stretching, and the roll peripheral speed V2 after stretching are expressed as 0.05 It is preferable that second ≦ T ≦ 1 second, more preferably 0.1 second ≦ T ≦ 0.5 second, and still more preferably 0.15 second ≦ T ≦ 0.3 second.

  As the installation position of the infrared heater, it is preferable to install the infrared heater on the upper surface or the lower surface of the film as shown in FIG. The position in the flow direction is not particularly limited as long as it is between the roll before stretching and the roll after stretching. The distance between the film and the heater tube is not particularly limited, but is preferably 20 mm or more and 100 mm or less. When the distance between the film and the heater tube is 20 mm or more, it is difficult to increase the possibility that the film will come into contact with the heater tube due to shake during film conveyance. Moreover, when the distance between the film and the heater tube is 100 mm or less, the effect of heating tends to be sufficient.

  The temperature Tc at the center of the film during stretching is a glass transition temperature Tg-10 ° C. or higher and Tg + 40 ° C. or lower, more preferably Tg−5 ° C. or higher and Tg + 10 ° C. or lower. When Tc is Tg−10 ° C. or higher, the film is likely to be plastically deformed and is less likely to break. Moreover, when a film is Tg + 40 degrees C or less, when peeling from the roll 3 after extending | stretching, possibility that a peeling pattern will arise is low. When the temperature Tc at the center is Tg−5 ° C. or more and Tg + 10 ° C. or less in the temperature region close to Tg, the elasticity at the center of the film is large, the temperature at the film periphery is higher than the temperature at the center of the film, and elasticity The effect of reducing the rate becomes relatively large, and thickness unevenness can be effectively suppressed.

  Although the measuring method of the said film temperature is not specifically limited, It is preferable to carry out with the radiation | emission thermometer installed and fixed between the extending | stretching rolls. Although the said thermometer is not restrict | limited in particular, It is preferable to install in the film upper surface 100 mm-300 mm away from the film conveyance surface, or a film lower surface. The output of the heater is changed by 40% to 100% and adjusted so that the desired temperature Tc at the center of the film is obtained.

  Moreover, it is preferable to install a reflecting plate on the opposite side of the heater from the film. Infrared light that has passed through the film is reflected and irradiated onto the film again, so that efficient heating is possible.

  Moreover, the means to heat the film peripheral part at the time of longitudinal stretching is demonstrated. In the present invention, examples of the means for heating the peripheral edge of the film include contact heating with a roll and non-contact heating with a heater, but heating with an infrared heater which is non-contact is preferred. The infrared heater is not particularly limited, but a heater capable of outputting a short wavelength in the maximum energy wavelength range of 1.2 to 1.7 μm and an output of 2.0 W or more per 1 mm width is preferable. Since the temperature of the coil in the heater tube is as high as 1000 ° C. or higher, the heater unit is preferably provided with a cooling mechanism by air cooling or water cooling. In particular, from the viewpoint of thickness accuracy, a water cooling mechanism that does not affect the film conveyance is preferable.

  The size of the infrared heater is not particularly limited, but the length (number) is sufficiently long in the width direction to be sufficiently longer than 30% of the film width W, and can secure a sufficient irradiation time even at a high line speed in the flow direction. It is preferable to use a heater.

  Any acrylic thermoplastic resin composition and rubber particle-containing thermoplastic resin composition can be suitably applied to the present invention.

  The rubber-like polymer-containing acrylic resin composition that is an example of the rubber particle-containing thermoplastic resin composition will be specifically described. In addition, the acrylic resin in this invention is not specifically limited, It does not specifically limit about the component, a particle size, etc. of a rubber-like acrylic body.

  Examples of the rubber-like polymer include polymers having a glass transition temperature of less than 20 ° C., and more specifically, for example, butadiene-based crosslinked polymers, (meth) acrylic crosslinked polymers, organosiloxane-based polymers. Examples thereof include cross-linked polymers. 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 containing the following acrylic ester rubber-like polymer ( Hereinafter, simply referred to as “acrylic graft copolymer”) can be preferably used.

  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 rubbery polymer is a rubbery polymer mainly composed of an acrylic ester, specifically, 50 to 100% by weight of the acrylic ester and other vinyl monomers copolymerizable. A monomer mixture consisting of 50 to 0% by weight (100% by weight) and 0.05 to 10 parts by weight of a polyfunctional monomer having two or more non-conjugated reactive double bonds per molecule (single A polymer obtained by polymerizing a monomer mixture (100 parts by weight) is preferable. 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, propyl acrylate, n-butyl acrylate, 2-butyl acrylate, isobutyl acrylate, benzyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, Examples thereof include phenyl acrylate and phenoxyethyl acrylate. These monomers may be used in combination of two or more. The amount of acrylic acid 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, still more preferably 70% by weight or more and 99% by weight or less, based on 100% by weight of the monomer mixture. Most preferably, it is at least 99% by weight. If it is 50% by weight or more, the impact resistance is hardly lowered, the elongation at the time of tensile fracture is hardly lowered, and cracks tend not to be generated when the film is cut.

  As other vinyl monomers that can be copolymerized, methacrylic acid esters are particularly preferred from the viewpoint of weather resistance and transparency, such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, Examples thereof include 2-butyl methacrylate, isobutyl methacrylate, benzyl methacrylate, cyclohexyl methacrylate, phenoxyethyl methacrylate, 2-ethylhexyl methacrylate, phenyl methacrylate, n-octyl methacrylate 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) acrylic esters.

  The polyfunctional monomer may be a commonly used monomer 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, trimethylol propane trimethacrylate, tetromethylol methane tetramethacrylate, dipropylene glycol dimethacrylate, and acrylates thereof can be used. Two or more of these polyfunctional monomers may be used.

  The amount of the polyfunctional monomer is preferably 0.05 to 10 parts by weight, and more preferably 0.1 to 5 parts by weight with respect to 100 parts by weight of the total amount of the monomer mixture. If the addition amount of the polyfunctional monomer is 0.05 parts by weight or more, a crosslinked product tends to be formed, and if it is 10 parts by weight or less, the crack resistance of the film tends not to be lowered.

  The rubber-like polymer comprises 40 to 100% by weight of methacrylic acid ester, 0 to 60% by weight of acrylic acid ester, 0 to 60% by weight of aromatic vinyl monomer, 0 to 10% by weight of polyfunctional monomer, and In addition, a polymer obtained by polymerizing 0 to 20% by weight of a vinyl monomer copolymerizable with these may be contained inside.

  The volume average particle diameter of the rubber-like polymer 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 20 nm or more, the crack resistance is unlikely to deteriorate. On the other hand, when it is 450 nm or less, the transparency is hardly lowered. In addition, in this specification, a volume average particle diameter means the volume average particle diameter measured by a dynamic scattering method, for example, can be measured by using MICROTRAC UPA150 (made 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 polymerizing ˜25 parts by weight in at least one stage are preferred. The methacrylic acid ester in the graft copolymer composition (monomer mixture) is preferably 50% by weight or more. If it is 50% by weight or more, the hardness and rigidity of the obtained film tend not 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 “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 as well. It is preferable that acid ester and acrylic acid ester are included. 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 ring structure-containing vinyl monomer and other monofunctional monomers copolymerizable therewith, It is more preferably 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 a total amount of 100% by weight of the ring structure-containing vinyl monomer and other monofunctional monomers copolymerizable therewith. The content is more preferably 1 to 98% by weight, still more preferably 1 to 50% by weight, and particularly preferably 5 to 50% by weight. Furthermore, (meth) acrylic acid and / or a salt thereof may be contained from the viewpoint that the thermal stability during the molding process is improved and the solvent resistance is improved.

  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%. When the graft ratio is 10% or more, the acrylic graft copolymer is less likely to aggregate in the molded body, and there is little possibility that transparency will be reduced or foreign matter will be generated. In addition, the elongation at the time of tensile fracture is difficult to decrease, and cracks tend not to occur when the film is cut. If it is 250% or less, the melt viscosity at the time of molding, for example, at the time of film molding, tends not to be high, and the moldability of the film tends to be difficult to decrease.

  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). From the weight of the obtained insoluble matter and the weight of the acrylate rubber-based polymer contained in the acrylic graft copolymer, 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 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. When the temperature is 30 ° C. or higher, productivity tends to be difficult to decrease, and when the temperature is 100 ° C. or lower, the target molecular weight is unlikely to become excessively large and the quality tends to be difficult to decrease. 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 usual redox polymerization initiators used 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 C2-C20 alkyl mercaptan, 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. Further, 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, and among them, dioctyl sulfosuccinate or polyoxyethylene alkyl ether phosphate 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 or 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 it is 0.05 parts by weight or more, the copolymer grain system does not become too large, and if it is 10 parts by weight or less, the copolymer grain system does not become too small, and the particle size distribution is hardly deteriorated.

  Although it does not specifically limit as a rubber-like polymer containing acrylic resin composition in this invention, It is preferable that it is a mixed composition of 1 or more types of acrylic rubber-like polymers and 1 or more types of acrylic resins.

  The acrylic rubbery polymer is preferably blended so that the rubbery polymer contained in the acrylic rubbery polymer is contained in an amount of 1 to 60 parts by weight in 100 parts by weight of the thermoplastic resin composition. It is more preferable to mix | blend so that it may contain-30 weight part, and it is still more preferable to mix | blend so that 1-25 weight part may be contained. When the amount is 1 part by weight or more, the crack resistance and vacuum formability of the film are deteriorated, and the photoelastic constant is increased and the optical isotropy is hardly deteriorated. On the other hand, when it is 60 parts by weight or less, the heat resistance, surface hardness, transparency, and bending whitening resistance of the film tend not to deteriorate.

  The acrylic rubbery polymer and acrylic resin may be mixed directly at the time of film production, or once the acrylic rubbery polymer and acrylic resin are mixed and pelletized, the film is again prepared. Production may be carried out.

（式中、Ｒ^１及びＲ^２は、それぞれ独立して、水素又は炭素数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、又は炭素数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及びＲ^５は、それぞれ独立して、水素又は炭素数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、又は炭素数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。 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 structural units derived from methyl methacrylate is preferable. Among them, a heat-resistant acrylic resin is preferable. For example, an acrylic resin in which an N-substituted maleimide compound is copolymerized as a copolymerization component, an anhydrous glutaric acid acrylic resin, an acrylic resin having a lactone ring structure, and glutar An aromatic vinyl-containing acrylic polymer obtained by polymerizing an imide acrylic resin, an acrylic resin containing a hydroxyl group and / or a carboxyl group, an aromatic vinyl monomer and another monomer copolymerizable therewith ( For example, a styrene-containing acrylic polymer obtained by polymerizing a styrene monomer and another monomer copolymerizable therewith) or a hydrogenated aroma obtained by hydrogenating a part or all of its aromatic ring Aromatic vinyl-containing acrylic polymers (for example, styrene-containing polymers obtained by polymerizing styrene monomers and other monomers copolymerizable therewith) The aromatic ring of Le polymer partially hydrogenated to the resulting partially hydrogenated styrene-containing acrylic polymer), it may be mentioned acrylic polymer and the like having a cyclic acid anhydride repeating units. From the viewpoint of heat resistance and optical properties, a glutarimide acrylic resin can be more preferably used. The glutarimide acrylic resin will be described in detail below. Specific examples of the glutarimide acrylic resin include the following general formula (1).

(In the formula, 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)

Wherein 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.)
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、水素又は炭素数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）を更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 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).

  Further, 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 several 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 .

  In general, the content of the glutarimide unit is preferably 1% by weight or more, more preferably 1% by weight to 95% by weight, and more preferably 2% by weight to 90% by weight of the glutarimide acrylic resin. % Is more preferable, and 3% by weight to 80% by weight is particularly preferable. 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.

  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 is unlikely to have insufficient heat resistance and mechanical strength during film processing is unlikely to decrease.

  In the glutarimide acrylic resin, other units other than the glutarimide unit, the (meth) acrylic acid ester unit, and the aromatic vinyl unit may be further copolymerized as 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 . Within the above range, it is difficult for the viscosity at the time of melt extrusion to increase, the molding processability to decrease, the productivity of the molded product to decrease, or the mechanical strength at the time of film processing to be insufficient.

  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.

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

  In addition, in order to make the post-longitudinal stretched film obtained by the present invention exhibit strength in the biaxial direction, it is preferable to continuously perform transverse stretching that extends in the width direction. The temperature at the time of transverse stretching is preferably Tg to Tg + 20 ° C. By performing lateral stretching in this range, it is possible to further improve the thickness unevenness.

  The uniaxially stretched film according to the present invention is a uniaxially stretched film containing a thermoplastic resin, and when the film width in the vertical direction with respect to the stretch direction is 100%, the distances from both extreme ends of the film in the vertical direction are respectively The average value of the difference between the film thickness at a position of 5% and the film thickness at the center of the film width is 10.0 μm or less. The average value is preferably 7.0 μm or less, more preferably 6.0 μm or less, still more preferably 5.0 μm or less, and particularly preferably 4.0 μm or less.

  The present invention will be described in more detail based on examples, but the present invention is not limited to these examples. Hereinafter, “parts” and “%” mean “parts by weight” and “% by weight” unless otherwise specified.

(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 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 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)
<Production of graft copolymer (B2)>
Creation of innermost layer polymer:
A mixture having the following composition was charged into a glass reactor, heated to 800 ° C. while stirring in a nitrogen stream, and then a monomer mixture consisting of 25 parts of methyl methacrylate and 1 part of allyl methacrylate and t-butyl. 25% of the mixed solution with 0.1 part of hydroperoxide was charged all at once and polymerized for 45 minutes.
Deionized water 220 parts Boric acid 0.3 parts Sodium carbonate 0.03 parts Sodium N-lauroyl sarcosinate 0.09 parts Sodium formaldehyde sulfoxylate 0.09 parts Ethylenediaminetetraacetic acid-2-sodium 0.006 parts 0.002 part of 1 iron Subsequently, the remaining 75% of this mixed solution was continuously added over 1 hour. After completion of the addition, the polymerization was completed by maintaining at the same temperature for 2 hours. In addition, 0.2 parts of sodium N-lauroyl sarcosinate was added to this sample. The polymerization conversion rate (polymerization amount / monomer charge amount) of the obtained innermost layer crosslinked methacrylic polymer latex was 98%.

Production of rubber particles:
The innermost layer polymer latex thus obtained was kept at 80 ° C. in a nitrogen stream, and after adding 0.1 part of potassium persulfate, a single unit consisting of 41 parts of n-butyl acrylate, 9 parts of styrene, and 1 part of allyl methacrylate. The monomer mixture was added continuously over 5 hours. During this time, 0.1 part of potassium oleate was added in three portions. After the addition of the monomer mixture, 0.05 parts of potassium persulfate was further added and held for 2 hours in order to complete the polymerization.
The polymerization conversion rate of the obtained rubber particles was 99%.

Preparation of rubber-containing graft copolymer:
The obtained rubber particle latex was kept at 80 ° C., 0.02 part of potassium persulfate was added, and then a monomer mixture of 14 parts of methyl methacrylate and 1 part of n-butyl acrylate was continuously added over 1 hour. The polymerization was carried out for 1 hour after the addition of the monomer mixture was completed. The polymerization conversion rate was 99%.

Furthermore, a monomer mixture of 5 parts of methyl methacrylate and 5 parts of n-butyl acrylate was continuously added over 0.5 hours. After completion of the addition of the monomer mixture, the mixture was held for 1 hour to obtain a rubber-containing graft copolymer latex. The polymerization conversion rate was 99%.
The obtained rubber-containing graph copolymer copolymer latex was salted out with calcium chloride, heat-treated and dried to obtain a white powdery rubber-containing graft copolymer. The average particle size was 250 nm.

(Production Example 3)
<Manufacture of resin pellets>
A single screw extruder using a full flight screw with a diameter of 40 mm was used, the temperature setting zone of the extruder was set to 255 ° C., the screw rotation speed was 52 rpm, 95 parts by weight of glutarimide acrylic resin (A1), and white A mixture of 5 parts by weight of the powdered graft copolymer (B2) was supplied at a rate of 10 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.

(Production Example 4)
<Film production equipment>
Film formation was performed using an extrusion manufacturing apparatus. As the extruder, a 65 mm diameter single screw extruder was used, and the pellets produced in Production Example 3 were supplied from a hopper provided with a nitrogen line. A gear pump was used so that the discharge amount was constant. As the T die, the die exit width in the film width direction is 1850 mm, and the lip clearance (the height of the die discharge port in the film thickness direction) can be adjusted by a manual uneven bolt. The lip (member constituting the discharge port) of the T die is divided into seven regions in the film width direction, and the temperature can be adjusted for each region. After discharging, the film was cooled and solidified by pulling it while being sandwiched between a cast roll and a touch roll. As the cast roll, a rigid roll having a diameter of 200 mm was used, the temperature of the roll was set to 100 ° C. using oil temperature control, and the film was rotated at a speed (take-off speed) of 20 m / min to form a 120 μm film. As the touch roll, an elastic roll having a metal sleeve was used. Thereafter, both ends were trimmed to obtain a smooth original film having a width of 1000 mm and a thickness of 120 μm. The glass transition temperature Tg of the film was 122 ° C. when evaluated by a midpoint method using DSC.

(manufacturing device)
In each Example and Comparative Example, the roll stretching machine shown in FIG. 1 was used. The preheating roll diameter was 250 mm, the roll diameter before stretching was 180 mm, the roll after stretching was 180 mm, and the cooling roll diameter was 250 mm. As shown in FIG. 1, the nip rolls are arranged so that the film conveyance path is parallel to the plane including the rotation axis of the two drawing rolls, and each of the drawing rolls and the nip rolls close to the two drawing rolls respectively. By sandwiching the film, the film was conveyed and longitudinally stretched. And both extending | stretching rolls were the conveyance directions of a film, and were mutually rotated in the same direction. Further, the holding portion interval L was set to 400 mm. Heating the entire film width of 1000 mm, an infrared heater of 1300 mm in width (irradiation length in the film flow direction is 160 mm) is directed from the top of the film to the center, 50 mm from the film, and at the center between the sandwiched parts installed. Moreover, the heater which heats a peripheral part was installed so that 150 mm of both ends of a film might be heated with the infrared heater of width 200mm. In order to measure the temperature Tc at the center of the film and the temperature Te at the peripheral edge of the film, a radiation thermometer (Fluke Corporation, Raytec XR) was installed from the position of the upper surface of the film 500 mm toward the film center of the heater irradiation section. In each example and comparative example, longitudinal stretching was performed at a peripheral speed of 20 m / min of the roll before stretching during stretching.

(Thickness evaluation method)
The measurement was performed at a 1 mm pitch in the width direction of the film with a contact-type thickness measuring machine (Anritsu Corporation KG3001A). The film width after stretching was 100%, and the film width direction position was normalized to -50% to + 50%. The 0% position is the center of the film. In addition, the thickness unevenness was shown by the value which averaged the difference with the center part (0% position) thickness in film position +/- 45% position.

Example 1
A means for heating the film peripheral part is installed downstream of the means for heating the entire film width, the temperature at the center of the film during stretching Tc = 122 ° C., the temperature at the film peripheral part during stretching Te = 132 ° C. As a result of stretching at a magnification of 2.0, a wrinkle-free film with a thickness variation of 1.5 μm was obtained.

(Example 2)
A means for heating the peripheral edge of the film is installed on the downstream side of the means for heating the entire film width, the temperature at the center of the film during stretching Tc = 122 ° C., the temperature at the peripheral edge of the film during stretching Te = 142 ° C. As a result of stretching at a magnification of 2.0 times, a film having a wrinkle-free thickness unevenness of 1.0 μm was obtained.

Example 3
A means for heating the peripheral edge of the film is installed downstream of the means for heating the entire film width, the temperature at the center of the film during stretching Tc = 142 ° C., the temperature at the peripheral edge of the film during stretching Te = 152 ° C. As a result of stretching at a magnification of 2.0 times, a film having a wrinkle-free thickness unevenness of 3.5 μm was obtained.

Example 4
A means for heating the film peripheral part is installed downstream of the means for heating the entire film width, the temperature at the center of the film during stretching Tc = 122 ° C., the temperature at the film peripheral part during stretching Te = 132 ° C. As a result of stretching at a magnification of 2.4, a film with wrinkle-free thickness unevenness of 2.0 μm was obtained.

(Comparative Example 1)
A means for heating the film peripheral portion is installed downstream of the means for heating the entire film width, the temperature at the center of the film at stretching Tc = 142 ° C., the temperature at the film peripheral edge at stretching Te = 142 ° C., and stretching As a result of stretching at a magnification of 2.0, a film with wrinkle-free thickness unevenness of 15.0 μm was obtained.

(Comparative Example 2)
A means for heating the film peripheral part is installed upstream of the means for heating the entire film width, the temperature at the center of the film during stretching Tc = 142 ° C., the temperature at the film peripheral part during stretching Te = 132 ° C. As a result of stretching at a magnification of 2.0, a wrinkled film with a thickness unevenness of 30.0 μm was obtained.

(Comparative Example 3)
A means for heating the film peripheral portion is installed upstream of the means for heating the entire film width, the temperature at the center of the film during stretching is Tc = 122 ° C., the temperature at the peripheral edge of the film during stretching is Te = 112 ° C. As a result of stretching at a magnification of 2.0, a wrinkled film with a thickness unevenness of 40.0 μm was obtained.

(Comparative Example 4)
A means for heating the film peripheral portion is installed downstream of the means for heating the entire film width, the temperature at the center of the film at stretching Tc = 142 ° C., the temperature at the film peripheral edge at stretching Te = 142 ° C., and stretching As a result of stretching at a magnification of 2.4, a wrinkled film with a thickness unevenness of 20.0 μm was obtained.

(Comparative Example 5)
The means for heating the film periphery is installed at the same position in the flow direction as the means for heating the entire film width, and the temperature Tc of the film center during stretching Tc = 142 ° C. and the temperature Te of the film periphery during stretching Te = 152 ° C. As a result of stretching at a stretching ratio of 2.0, a wrinkled film with a thickness unevenness of 12.0 μm was obtained.

1: Preheating roll group, 2: Roll before stretching, 3: Roll after stretching, 4: Cooling roll, 5: IR heater (heating the entire width of the film), 6: IR heater (heating the film peripheral edge), 7: Reflecting plate , 8: Nip roll, 9: Nipping part interval

Claims (10)

A method for producing a film comprising a stretching step of stretching a raw film containing a thermoplastic resin in a uniaxial direction,
In the stretching step, after reducing the film elastic modulus in the entire film width in the vertical direction with respect to the uniaxial direction, further reducing the film elastic modulus in the peripheral edge of the film in the vertical direction,
The method for producing a film, wherein the film peripheral edge is a region in which the distance from both extreme ends of the film in the vertical direction is 5% or more and 30% or less, respectively, when the film width is 100%. A method for producing a film comprising a stretching step of stretching a raw film containing a thermoplastic resin in a uniaxial direction,
In the stretching step, the entire film width in the vertical direction with respect to the uniaxial direction is heated, the film temperature at the center of the film width is set to Tc, the film peripheral edge in the vertical direction is heated, and the film peripheral edge The film temperature is Te,
The film peripheral portion is a region in which the distance from both end portions of the film in the vertical direction is 5% or more and 30% or less, respectively, when the film width is 100%.
The temperatures Tc and Te are represented by the following formula (1):
Te-Tc> 0 ° C. (1)
The film manufacturing method characterized by satisfy | filling. Stretching in the stretching step is performed while transporting the raw film in the uniaxial direction,
The method for producing a film according to claim 2, wherein a second heating means for heating the peripheral edge of the film is disposed downstream of the first heating means for heating the entire film width in the film transport direction.   The method for producing a film according to claim 2 or 3, wherein the heating of the entire film width and the heating of the peripheral edge of the film are performed by a radiation heating device.   The method for producing a film according to any one of claims 1 to 4, wherein the draw ratio is from 1.1 times to 3.0 times. Stretching in the stretching step is performed while sandwiching the original film with a pair of sandwiching portions disposed apart in the uniaxial direction,
L / w is 0.1 or more and 2.0 or less, where w is the width of the original film and L is the distance between the pair of sandwiching portions. The method for producing a film according to one item.   The width of the original fabric film is 900 mm or more and 2000 mm or less, The manufacturing method of the film as described in any one of Claims 1-6 characterized by the above-mentioned. Stretching means for stretching a raw film containing a thermoplastic resin in a uniaxial direction,
First elastic modulus lowering means for reducing the film elastic modulus in the entire film width in the direction perpendicular to the uniaxial direction;
Second elastic modulus lowering means for further reducing the film elastic modulus at the film peripheral edge in the vertical direction after the elastic modulus lowering by the first elastic modulus lowering means;
A film manufacturing apparatus comprising:
The said film peripheral part is an area | region where the distance from the film both ends in the said perpendicular direction is 5% or more and 30% or less, respectively, when the said film width is 100%. Stretching means for stretching a raw film containing a thermoplastic resin in a uniaxial direction,
A first heating means that heats the entire film width in the direction perpendicular to the uniaxial direction and sets the film temperature at the center of the film width as Tc;
After the heating by the first heating means, the second heating means for heating the film peripheral edge in the vertical direction and setting the film temperature at the film peripheral edge to Te,
A film manufacturing apparatus comprising:
The film peripheral portion is a region in which the distance from both end portions of the film in the vertical direction is 5% or more and 30% or less, respectively, when the film width is 100%.
The temperatures Tc and Te are represented by the following formula (1):
Te-Tc> 0 ° C. (1)
An apparatus for producing a film characterized by satisfying   A uniaxially stretched film containing a thermoplastic resin, when the film width in the vertical direction with respect to the stretching direction is 100%, the film thickness at a position where the distance from both ends of the film in the vertical direction is 5%, and The average value of the difference with the film thickness in the said film width center is 10.0 micrometers or less, The uniaxially stretched film characterized by the above-mentioned.

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