JP2008068521A - Laminated film and feed block - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a film which is excellent in lamination precision and thickness inhomogeneity, without reference to the magnitude of a difference in the viscosity characteristics and compatibility of a resin, and a feed block. <P>SOLUTION: This laminated film, which is constituted by making eleven or more layers overlie one another, is characterized as follows: each layer of the laminated film is composed of a thermoplastic resin; the outermost layer (X) on at least one side is four or more times thicker than the thinnest layer (Z) of the laminated film; and the layer (Y) adjacent to the layer (X) is also four or more times thicker than the layer (Z). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a laminated film in which layers made of at least two kinds of thermoplastic resins are laminated and a feed block used for the production thereof.

  The technique of laminating two or more kinds of resins can give various characteristics to a film made of only a single resin. For example, imparting weather resistance by laminating another resin to a resin having low weather resistance, or imparting gas barrier property by laminating another resin to a resin having low gas barrier properties Is possible. As described above, since various properties can be imparted to the resin as the base material, this method is used in many products on the market such as food packaging materials.

  In addition, in the multilayer laminated film with 11 or more layers of resin, in addition to the above characteristics, unique properties are provided by having a multilayer structure such as improved tear resistance and improved light interference reflectivity. For example, a multi-layered film is excellent in tear resistance, and is used as a material that can prevent breakage and scattering of glass by sticking the film to the glass surface (for example, Patent Document 1). In addition, by alternately laminating resin layers having different refractive indexes, it is possible to produce a film that expresses interference reflection of light and selectively reflects a specific wavelength (see Patent Document 2, for example).

The laminated film can be formed by a coextrusion method using several extruders or a laminating method in which the films are laminated together. Among them, the co-extrusion method is capable of forming a large number of layers in a single step, and is very advantageous from the viewpoint of cost. Therefore, it is generally used for forming a multilayer laminated film. . However, in the case of coextrusion, when the melting resin, glass transition point, melt viscosity, affinity, etc. of the laminated resin are different, there is a problem that uneven thickness of the laminated film or uneven thickness of the laminated layers occurs. is there. For this reason, the combinations of resins that can actually be laminated are limited, and it is difficult to easily form a laminated film having high characteristics.
A multilayer film that thickens the outermost layer has been proposed as a technique that leads to countermeasures against uneven thickness of laminated films and uneven thickness of laminated layers (Patent Document 3). This method has been proposed for the purpose of improving the handleability by adjusting the film thickness, but has shown some effect on the suppression of film thickness unevenness and lamination unevenness due to the thickening of the outermost layer. However, if the difference in viscosity characteristics of the resin is large, uneven thickness and lamination will still occur, and this outermost layer joins through the outermost flow path after forming the multilayer flow, and before the outermost layer is formed Since there is no effect on the unevenness of the laminated thickness and the unevenness of the film thickness, a further improvement technique is desired.
JP 10-76620 A (page 2) JP 2005-288784 A (2nd page) Japanese Patent Laying-Open No. 2003-251675 (second term)

  The present invention has been made in view of the above-described problems of the prior art, and it is an object of the present invention to provide a film having excellent lamination accuracy and excellent thickness uniformity regardless of the difference in viscosity characteristics and affinity of resins. .

  In order to solve the above-mentioned problem, it is a laminated film in which 11 layers or more are laminated, each layer of the laminated film is made of a thermoplastic resin, and the layer thickness of the outermost layer (X) on at least one side is the thinnest layer in the laminated film. The layer thickness of (Z) is four times or more, and the layer thickness of the layer (Y) adjacent to X is also four times or more the layer thickness of Z.

  The laminated film of the present invention is a laminated film in which 11 or more layers are laminated, each layer of the laminated film is made of a thermoplastic resin, and the layer thickness of the outermost layer (X) on at least one side is the thinnest layer in the laminated film. Since the layer thickness of (Z) is 4 times or more and the layer thickness of the layer (Y) adjacent to X is also 4 times or more of the layer thickness of Z, the viscosity characteristics and affinity of the resin Regardless of the difference in properties, it is possible to provide a film having excellent lamination accuracy and excellent thickness uniformity.

In order to solve the above object, the laminated film of the present invention is a laminated film in which 11 or more layers are laminated, each layer of the laminated film is made of a thermoplastic resin, and the layer thickness of at least one outermost layer (X) is at least one side. The layer thickness of the thinnest layer (Z) in the laminated film should be 4 times or more, and the layer thickness of the layer (Y) adjacent to X must also be 4 times or more the layer thickness of Z.

  In the laminated film of the present invention, the layer thickness of X on at least one side needs to be 4 times or more of the layer thickness of Z, and the layer thickness of the layer Y adjacent to X needs to be 4 times or more of the layer thickness of Z. . In the production of a laminated film, it is known that the difference in melt viscosity and the difference in affinity of thermoplastic resins to be laminated greatly contribute to the lamination accuracy. As a result of intensive studies, the authors have found that, even for a laminated film of 11 layers or more, it is the outermost layer and the layer adjacent to the outermost layer that cause the lamination accuracy to be disturbed. It has been discovered that by making the layer thickness and the layer thickness of Y 4 times or more compared with the layer thickness of Z, the unevenness of the thickness of the laminated film and the unevenness of the layer thickness are reduced. Preferably, the thickness of the outermost layer on both sides of the film is 4 times or more of the layer thickness of Z, and the thickness of Y adjacent to the outermost layer is 4 times or more of the layer thickness of Z. More preferably, the thickness of the outermost layer on both surfaces of the film is 10 times or more of the layer thickness of Z, and the layer thickness of Y adjacent to the outermost layer is 10 times or more of the layer thickness of Z. In this case, a film having a very high lamination accuracy and excellent thickness uniformity can be easily obtained even in a combination of thermoplastic resins having a large viscosity difference.

  In the laminated film of the present invention, it is more preferable that the layer thickness of each layer from at least the outermost layer on one side of the film to the fourth layer on the inner layer side is at least four times the layer thickness of Z. When each layer thickness from the outermost layer to the fourth layer on the inner layer side is 4 times or more the layer thickness of Z, even when the flow rate is extremely high, or when using a film forming apparatus with a short channel diameter, A film having very high lamination accuracy and excellent thickness uniformity can be obtained.

  In the present invention, it must be a laminated film formed by laminating 11 or more layers of at least two types of thermoplastic resins. More preferably, they are 11 layers or more and 30000 layers or less, More preferably, they are 11 layers or more and 3000 layers or less. The upper limit of the number of stacked layers is not particularly limited, but for reasons such as an increase in the size of the device, the limit is substantially about 30000 layers.

  The thermoplastic resin in the present invention may be a homo resin, a copolymer or a blend of two or more. In each resin, various additives such as antioxidants, antistatic agents, crystal nucleating agents, inorganic particles, organic particles, viscosity reducers, thermal stabilizers, lubricants, infrared absorbers, ultraviolet absorbers, A dopant for adjusting the refractive index may be added.

  Examples of thermoplastic resins include polyolefin resins such as polyethylene, polypropylene, polystyrene, and polymethylpentene, alicyclic polyolefin resins, polyamide resins such as nylon 6 and nylon 66, aramid resins, polyethylene terephthalate, polybutylene terephthalate, and polypropylene terephthalate.・ Polybutyl succinate ・ Polyester resin such as polyethylene-2,6-naphthalate, polycarbonate resin, polyarylate resin, polyacetal resin, polyphenylene sulfide resin, tetrafluoroethylene resin, trifluoroethylene resin, trifluorochloroethylene resin・ Fluorine resin such as ethylene tetrafluoride-6-propylene copolymer / vinylidene fluoride resin, acrylic resin, methacrylic resin, polyacetal resin, It can be used polyglycolic acid resin, polylactic acid resin, and the like. Among these, polyester is particularly preferable from the viewpoint of strength, heat resistance, transparency, and low melt viscosity.

  The polyester referred to in the present invention refers to a homopolyester or a copolyester that is a polycondensate of a dicarboxylic acid component skeleton and a diol component skeleton. Here, typical examples of the homopolyester include polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate, poly-1,4-cyclohexanedimethylene terephthalate, and polyethylene diphenylate. In particular, polyethylene terephthalate is preferable because it is inexpensive and can be used in a wide variety of applications.

  The copolyester in the present invention is defined as a polycondensate comprising at least three or more components selected from the following components having a dicarboxylic acid skeleton and components having a diol skeleton. Components having a dicarboxylic acid skeleton include terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 4,4′-diphenyldicarboxylic acid 4,4′-diphenylsulfone dicarboxylic acid, adipic acid, sebacic acid, dimer acid, cyclohexanedicarboxylic acid and ester derivatives thereof. Examples of the component having a glycol skeleton include ethylene glycol, 1,2-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentadiol, diethylene glycol, polyalkylene glycol, and 2,2-bis. (4′-β-hydroxyethoxyphenyl) propane, isosorbate, 1,4-cyclohexanedimethanol, spiroglycol and the like can be mentioned.

In the laminated film of the present invention, it is preferable that the shear viscosity S of the resin that forms at least the outermost layer on one side of the film is lower than the shear viscosity S of the resin that forms adjacent layers measured at the same temperature. The shear viscosity S mentioned here is a value of the complex viscosity at a shear rate of 15 s ⁻¹ in dynamic viscoelasticity measurement using a rotational viscometer. The temperature at which the measurement is performed is a temperature at which all the laminated resins are in a molten state, and T to T + 50 ° C. where T is the highest melting point among the melting points of all the laminated resins. It is measured in the temperature range. In the laminating flow of the molten resin in the film forming apparatus, when the shear viscosity S of the resin located on the outermost wall is lower than the shear viscosity S of the adjacent layer, the laminating accuracy is very high and the thickness uniformity is excellent. Film. Preferably, the shear viscosity S of the resin on the outermost layer on both sides of the film is lower than the shear viscosity S of the resin in the adjacent layer. In this case, in the laminating flow of the molten resin in the film forming apparatus, the shear stress on the interface closest to the wall surface is reduced on both wall surfaces, and the film thickness unevenness and the lamination thickness unevenness on both surfaces of the film are reduced. Can be suppressed.
The present invention comprises thermoplastic resin A and thermoplastic resin B, which was difficult in the prior art, and the difference in shear viscosity S at the same temperature between thermoplastic resin A and thermoplastic resin B is 100 Pa · s or more. Even in some cases, it is possible to obtain a film with less lamination unevenness and excellent thickness uniformity. More preferably, it is 100 Pa · s or more and 2000 Pa · s or less. If it is 2000 Pa · s or more, it is difficult to reduce the stacking unevenness.

  In the laminated film of the present invention, the thermoplastic resin A and the thermoplastic resin B are included, and the absolute value of the SP value difference between the thermoplastic resin A and the thermoplastic resin B is preferably 0.5 or more and 5 or less. . When the absolute value of the difference in SP value is 0.5 or more, slip in the interface is likely to occur in the conventional technique and the stacking unevenness is remarkable, but this is overcome in the present invention. On the other hand, when the difference in SP value is larger than 5, delamination in the laminated film is very likely to occur, and it is difficult to reduce lamination unevenness.

  In the laminated film of the present invention, the thickness of the layer adjacent to the outermost layer on at least one side is preferably 1 μm or more and 30 μm or less, and the thickness of the thinnest layer in the film is preferably 1 nm or more and 500 nm or less. In such a case, even if the layer thickness includes a large number of nano-order layers, the layers can be stacked with high stacking accuracy. More preferably, the thickness of the layer adjacent to the outermost layer on both sides is 1 μm or more and 10 μm or less, and the thickness of the thinnest layer in the film is 50 nm or more and 500 nm or less. In this case, lamination with higher lamination accuracy is possible, and it is suitable for interference reflection films and optical waveguide films that require high-precision lamination on the nano order.

  Next, the preferable manufacturing method of the stretched film of this invention is demonstrated below.

  Two types of resins A and B are prepared in the form of pellets. The pellets are dried in hot air or under vacuum as necessary, and then supplied to a separate extruder. In the extruder, the resin melted by heating to a temperature equal to or higher than the melting point is made uniform in the amount of resin extruded by a gear pump or the like, and foreign matter or denatured resin is removed through a filter or the like.

  Resins sent from different flow paths using these two or more extruders are then sent to the multi-layer laminating apparatus. As the multi-layer laminating apparatus, a multi-manifold die, a feed block, a static mixer or the like can be used, and these may be arbitrarily combined. In order to achieve that 11 or more layers of at least two or more types of thermoplastic resins, which is a feature of the present invention, are achieved, it is more preferable to use a feed block having one member having many slits. By using a feed block having a slit, it is possible to easily stack 11 or more layers. Furthermore, when the number of stacked layers is 500 or more, it is preferable to use a feed block including at least two members having a large number of slits separately. Use of such a feed block is advantageous from the viewpoint of manufacturing cost of the device because the device does not become extremely large, and has high accuracy even when there are few foreign matters due to thermal deterioration and the number of layers is extremely large. Layering is possible. Also, the stacking accuracy in the width direction is significantly improved as compared with the prior art. It is also possible to form an arbitrary layer thickness configuration.

  The feed block having one member having two slits of two kinds of resins will be described in detail below. FIG. 1 shows a portion for forming a laminate from resins A and B supplied separately in the feed block lock. In FIG. 1, members 1 to 5 are stacked in this order to form a stacking device 6. 1 supplies resin A from a resin introduction port 7 provided in the resin introduction member 2 and supplies resin B from a resin introduction port 8 provided in the resin introduction member 4.

  The resin A introduced into the resin introduction member 2 is guided to the liquid reservoir 9 provided in the resin introduction member 2 and introduced into the slit plate 3. Similarly, the resin B is also introduced into the slit plate 3 after being guided to the liquid reservoir 10 provided in the resin introduction member 4. The resins A and B introduced into the slit plate 3 are stacked in the slit plate, and then guided from the slit plate outlet 11 to the die.

  In the shape of the slit plate in the present invention, the shape of the slit (Sx) located on the outermost wall surface side of at least one side of the slit plate and the shape of the slit (Sy) located adjacent to Sx are the same as Sx in the same slit plate. It is preferable that the following formula 1 and the following formula 2 are satisfied with respect to the shape of at least one of the slits (S) except Sy and Sy. The slit here refers to a gap into which the resin corresponding to each layer is introduced, the length of the slit corresponds to the length (L) in the Z direction in FIG. 2, and the width of the slit is the figure. 2 corresponds to the length (t) in the Y direction. The shape of the slit is related to the amount of resin discharged from the slit and thus affects the layer thickness. When the shape of Sx and Sy on the outermost wall side of at least one side satisfies the following formula 1 and the following formula 2 for any of the remaining slits, the layer thickness of X on at least one side is four times the layer thickness of Z and X It becomes possible to produce a laminated film in which the layer thickness of Y and Y is four times or more of the layer thickness of Z, which is effective in suppressing film thickness unevenness and lamination unevenness. More preferably, the shape of Sx and the shape of Sy located on both outermost wall sides of the slit plate satisfy the following formula 1 and the following formula 2 with respect to the shape of any slit (S) other than Sx and Sy. It is. In this case, the layer thickness of the outermost layer (X) is at least four times the layer thickness of the thinnest layer (Z) in the film and the layer thickness of the layer (Y) adjacent to X on both surfaces of the laminated film formed. It becomes four times or more the layer thickness of Z, and it becomes possible to form a film with high lamination accuracy and excellent thickness uniformity.

4L (Sx) / t (Sx) ³ ≦ L ′ / t ′ ³ (Formula 1)
4L (Sy) / t (Sy) ³ ≦ L ′ / t ′ ³ (Formula 2)
L (Sx): Sx length (mm)
t (Sx): Sx width (mm)
L (Sy): Sy length (mm)
t (Sy): Sy width (mm)
L ′: Length of S (mm)
t ′: S width (mm)
As the shape of the slit, it is preferable that the slit area on the side where the resin is introduced is not the same as the slit area on the side where the resin is not introduced. With such a structure, the flow rate distribution on the side where the resin is introduced and the side where the resin is not introduced can be reduced, so that the lamination accuracy in the width direction is improved. Further, (slit area on the side where no resin is introduced) / (slit area on the side where the resin is introduced) is preferably 0.2 or more and 0.9 or less. More preferably, it is 0.5 or less. Moreover, it is preferable that the pressure loss in a feed block will be 1 Mpa or more. Moreover, it is preferable that the slit length (the longer one of the Z-direction slit lengths in FIG. 1) is 20 mm or more. On the other hand, the thickness of each layer can be controlled by adjusting the gap and length of the slit.

  It is also preferable to have a manifold corresponding to each slit. Because the manifold makes the flow velocity distribution in the width direction (Y direction in FIG. 1) uniform inside the slit, the lamination ratio in the width direction of the laminated films can be made uniform, and even a large area film can be accurately obtained. It becomes possible to laminate.

  In the slit plate of the present invention, the slit tip angle is preferably 1 ° or more and 120 ° or less. The slit tip angle here is the angle of the tip of the partition provided between the slits, and is determined as described below. The locations where the width t ″ of the partition walls in the stacking direction (Y direction in FIG. 3) is the largest in the partition walls are designated as a and a ′, and the partition wall width is ½ of t ″ and the most of the partition walls. Let b and b ′ be the tips (locations where the maximum value in the Z direction in FIG. 3 is taken). At that time, an angle 12 is formed between a straight line C passing through a and parallel to the wall surface and a straight line passing through point b and touching the partition wall, and a straight line C ′ passing through the wall surface and parallel to the wall surface and passing through point b ′ and a straight line contacting the partition wall. If the angle is 12 ′, the slit tip angle is the sum of the angles of 12 and 12 ′. (Figure 3). In this case, the angles 12 and 12 'are treated as 0 ° or more and less than 180 °. By making the slit tip angle an acute angle, it becomes possible to suppress the difference in the flow rate of each resin when the interface is formed, so that the flow is less disturbed, the lamination accuracy is high, and the thickness is uniform. An excellent film can be formed. Further, it is preferable that the tip shape is the center line 13 in the stacking direction of the slit outlet, and the tip b is located near the center line 13 from the center of the slit partition wall in the stacking direction. Since the resin extruded from the slit immediately flows toward the center line 13 when it is separated from the slit, the flow can be made smoother because the tip b is at a position close to the center line 13. More preferably, the slit tip angle is not less than 60 ° and not more than 120 °. In this case, the width of the slit plate at the front end of the device is sufficiently large, so that there is no deformation even with a large pressure in the slit, and it is difficult for deformation due to maintenance in repeated use. Lamination accuracy can be maintained.

  In the slit plate of the present invention, it is preferable that the flow path width has a portion that decreases in the thickness direction and the contraction angle is 15 ° or more and 80 ° or less. The contraction angle here is shown below. The points where the flow path width in the stacking direction (the Y direction in FIG. 4) becomes the largest downstream of all the slits in the slit plate are d and d ′, and the short tube in the stacking plate is the most in the stacking direction. The points where the flow path becomes small are denoted by e and e ′ (d and e are on the same wall surface, and d ′ and e ′ are on the same wall surface). At this time, the angle (14) formed by the straight line and the line segment de passing through the point d and the straight line segment dd ′, and the straight line passing through the point d ′ and the straight line segment dd ′ and the straight line segment d′ e ′. The angle formed by the angle (14 ′) is defined as the contraction angle. (FIG. 4). If the angles of 14 and ‘14’ are different, the average value is taken. When the contraction angle is less than 15 °, the flow passage area in the laminating apparatus becomes large and the film forming apparatus becomes large, which is not preferable. This can be dealt with by reducing the slit width t. In this case, however, the size of the slit becomes small, which is problematic in terms of accuracy and durability of slit processing, and is not preferable. On the other hand, if the contraction angle is larger than 80 °, flow turbulence such as vortex or stagnation may occur in the resin flow when the flow path contracts. Therefore, when the contraction angle is 15 ° or more and 80 ° or less, it is possible to reduce the size of the laminating apparatus, and it is possible to suppress the flow turbulence that causes the film thickness unevenness and the stacking unevenness. . More preferably, the contraction flow angle is 30 ° or more and 60 ° or less. In this case, the size of the laminating apparatus can be stored in an appropriate size, and a film having high lamination accuracy and excellent thickness uniformity can be formed.

Moreover, in the slit plate of the present invention, a line segment (A) connecting between both wall surfaces passing through the tips of the two slits located on the outermost wall surface side of the slit plate and a line segment connecting the position where the flow path width becomes the shortest. It is preferable that the cross-sectional area of the flow channel with respect to (B) is within ± 20% of the area of a quadrangle having A and B as the upper side and the bottom side. Here, the line segment A is a line when the straight line passing through the end of the slit partition wall located on the outermost wall side (the place where the value of Z in FIG. 4 becomes the largest) and the wall surface are intersections c and c ′. The segment cc ′, the segment B is the segment ee ′, and the quadrangle having A and B as the upper side and the bottom side is the quadrangle cc′e′e. (FIG. 4). The flow stacked at the slit flows in the direction of the center line 13 immediately after the slit. For this reason, as the distance from the slit to the start of the contraction increases, the flow area of the layer on the outermost wall side increases, which is not preferable because it causes flow disturbance such as vortex and retention in the layer. Moreover, in the location where the flow contraction of the flow path occurs, the flow rate can be smoothed because the flow contraction rate of the flow path is constant, which is effective in suppressing flow turbulence. From the above, when the cross-sectional area of the flow path between A and B is within ± 20% of the area of a rectangle with A and B being the top and bottom sides, the flow that causes unevenness in film thickness and lamination Effective for suppressing unevenness. More preferably, the cross-sectional area of the flow path between A and B is within ± 10% of the area of a quadrangle having A and B as the top and bottom sides. In this case, the lamination accuracy is very high and the thickness is uniform. It becomes possible to form a film excellent in.
The molten laminate formed in the desired layer configuration in this way is then formed into a desired shape by a die and then discharged. And the sheet | seat laminated | stacked in the multilayer discharged | emitted from die | dye is extruded on cooling bodies, such as a casting drum, and is cooled and solidified, and a casting film is obtained. At this time, it is preferable to use a wire-like, tape-like, needle-like, or knife-like electrode to be brought into close contact with a cooling body such as a casting drum by an electrostatic force and rapidly solidify. Also preferred is a method in which air is blown out from a slit-like, spot-like, or planar device to be brought into close contact with a cooling body such as a casting drum and rapidly cooled and solidified, or brought into close contact with a cooling body with a nip roll and rapidly solidified.

  The casting film thus obtained is preferably biaxially stretched as necessary. Biaxial stretching refers to stretching in the longitudinal direction and the width direction. Stretching may be performed sequentially in two directions or simultaneously in two directions. Further, re-stretching may be performed in the longitudinal direction and / or the width direction. In particular, in the present invention, it is preferable to use simultaneous biaxial stretching from the viewpoint of suppressing in-plane orientation difference and suppressing surface scratches.

  First, the case of sequential biaxial stretching will be described. Here, stretching in the longitudinal direction refers to stretching for imparting molecular orientation in the longitudinal direction to the film, and is usually performed by a difference in peripheral speed of the roll, and this stretching may be performed in one step. Alternatively, a plurality of roll pairs may be used in multiple stages. Although it changes with kinds of resin as a magnification of extending | stretching, 2 to 15 times is preferable normally, and when polyethylene terephthalate is used for either of the resin which comprises a laminated | multilayer film, 2 to 7 times are used especially preferably. Moreover, as extending | stretching temperature, the glass transition temperature-glass transition temperature +100 degreeC of resin which comprises a laminated | multilayer film are preferable.

  The uniaxially stretched film thus obtained is subjected to surface treatment such as corona treatment, flame treatment, and plasma treatment as necessary, and then functions such as slipperiness, easy adhesion, and antistatic properties are provided. It may be applied by in-line coating.

  The stretching in the width direction refers to stretching for giving the film an orientation in the width direction. Usually, the tenter is used to convey the film while holding both ends of the film with clips, and the film is stretched in the width direction. Although it changes with kinds of resin as a magnification of extending | stretching, 2 to 15 times is preferable normally, and when polyethylene terephthalate is used for either of the resin which comprises a laminated | multilayer film, 2 to 7 times are used especially preferably. Moreover, as extending | stretching temperature, the glass transition temperature-glass transition temperature +120 degreeC of resin which comprises a laminated | multilayer film are preferable.

  The biaxially stretched film is preferably subjected to a heat treatment at a temperature not lower than the stretching temperature and not higher than the melting point in the tenter in order to impart flatness and dimensional stability. After being heat-treated in this way, it is gradually cooled down uniformly, then cooled to room temperature and wound up. Moreover, you may use a relaxation process etc. together in the case of annealing from heat processing as needed.

An evaluation method of physical property values used in the present invention will be described.
(Method for evaluating physical properties)
(1) Lamination thickness, the number of laminations, and lamination structure The layer structure of the film was obtained by observing an electron microscope with respect to a sample obtained by cutting a cross section using a microtome. That is, using a transmission electron microscope H-7100FA type (manufactured by Hitachi, Ltd.), the cross section of the film was enlarged and observed at an acceleration voltage of 75 kV, a cross-sectional photograph was taken, and the layer configuration and each layer thickness were measured. In addition, in order to obtain a high contrast by photographing at a magnification of 10,000 times when the laminated layer thickness is 1 μm or more, and when the layer thickness is less than 1 μm, a magnification method using a known RuO ₄ is used. Using.

A specific method for obtaining the laminated structure will be described. TEM photographic images were captured using CanonScan D123U with an image size of 720 dpi. The image is saved in the JPEG format, and then image processing software Image-Pro Plus ver. 4 (sales company Planetron Co., Ltd.) was used to open this JPG file and perform image analysis. In the image analysis process, the relationship between the thickness in the thickness direction and the average brightness of the area sandwiched between the two lines in the width direction was read as numerical data in the vertical thick profile mode. Using the spreadsheet software (Excel2000), the position (nm) and brightness data were subjected to numerical processing of sampling step 6 (decimation 6) and 3-point moving average. Furthermore, the data obtained by periodically changing the brightness is differentiated, and the maximum value and the minimum value of the differential curve are read by the VBA program. Calculated. This operation was performed for each photograph, and the layer thicknesses of all layers were calculated.
(2) Measurement of melt viscosity S Dynamic viscoelasticity measurement was performed using a rotational viscometer MR-300 solid meter (manufactured by Rheology). For the measurement, a parallel disk (diameter 18 mm) was used, and measurement was performed under the conditions of 270 ° C., amplitude 1 °, and shear rate 0.6 to 31 s ⁻¹ under N ₂ atmosphere. Among the obtained data, the complex viscosity at a shear rate of 15 ⁻¹ was defined as shear viscosity S. In addition, about the resin dried and used for film forming in the Example, it dried on the same conditions also in this measurement.
(3) Measurement of thickness unevenness of film Using a film thickness tester “KG601A” and an electronic micrometer “K306C” (both manufactured by Anritsu), the film thickness was measured when the film was wound at a speed of 1.5 m / min. The thickness was measured for 1 minute at a 10 Hz period. Regarding the film thickness at all locations of the obtained film, the maximum thickness was d _max , the minimum thickness was d _min , the average thickness was d _av , and the thickness unevenness was (d _max −d _min ) / d _av . The measurement is performed with respect to the longitudinal direction of the film, and the measurement position is the film thickness unevenness which is the largest value among the unevenness of the film thickness obtained by measuring 5 positions at equal intervals in the width direction. Table 1 shows that the film thickness non-uniformity is less than 0.05: ◎, 0.05 to less than 0.1: ◯, 0.1 to less than 0.2: Δ, 0.2 or more Things are marked as x.
(4) Definition of stacking thickness unevenness Regarding the position in the width direction where the value of the film thickness unevenness is the largest in the measurement of (3), the cross section in the flow direction of the film where the film thickness is the thickest and the thinnest And a layer thickness profile of the cross section was created by the method described in (1). Based on the obtained layer thickness profile, for each layer that is laminated, the layer thickness at the location where the film thickness is large is W _max , the film thickness at the small location is W _min , (W _max −W _min ) / (W _max + W _min ). Lamination unevenness is calculated for all layers, and the largest value among them is taken as the unevenness of the film lamination thickness. Table 1 shows that the film thickness non-uniformity is less than 0.1: ０．１, 0.1 to less than 0.2: ○, 0.2 to less than 0.5: Δ, 0.5 or more Things are marked as x.

(Example 1)
A thermoplastic resin A and a thermoplastic resin B were prepared as two types of thermoplastic resins. As the resin A, polyethylene terephthalate (PET) was used after being dried under vacuum at 180 ° C. The PET resin is polymerized by the method described below. First, calcium acetate was added as a transesterification reaction catalyst to a mixture of 100 parts by weight of dimethyl terephthalate and 60 parts by weight of ethylene glycol, and the mixture was heated and heated to distill methanol to conduct a transesterification reaction. Subsequently, the transesterification product was added with antimony trioxide as a polymerization catalyst and phosphoric acid as a heat stabilizer, and transferred to a polycondensation reaction tank. Next, the reaction system was gradually depressurized while being heated and heated, and the inside was stirred at 290 ° C. under reduced pressure to polymerize while distilling methanol to obtain a PET resin. As the resin B, polypropylene (PP) [Nobrene WF836DG3 manufactured by Sumitomo Chemical] was used without being dried. These resins were fed to separate extruders.

  Resins A and B were each melted at 270 ° C. with an extruder, passed through a gear pump and a filter, and then merged in a 201-layer feed block. The amount of resin discharged from the gear pump is the same for both resins. As the 201-layer feed block, an apparatus as shown in FIG. 1 was used. The feed block includes one slit plate including 201 slits, and S (1), S (2),..., S (N),. , S (200), S (201), S (1), S (2), S (3), S (4), S (198), S (199), S (200), The length of the slit of S (201) is L and the width is 2.2t, and the other slit shapes are the length L and the width t. The feed block is designed so that the resin A flows through the odd-numbered slit plates and the resin B flows through the even-numbered slits. The slit plate has a slit tip angle of 90 °, a contraction angle of 45 °, and a D / T of 100%. As a result, the formed film has 201 layers alternately laminated with A, B, A,..., A, B, A, and the layer thickness from the outermost layer on both sides of the film to the fourth layer on the inner layer side. Is about 10 times the Z layer thickness. A laminate comprising 51 layers laminated using the feed block was formed into a sheet shape, rapidly cooled and solidified on a casting drum maintained at a surface temperature of 25 ° C. by electrostatic application, and wound up. The film thus obtained had a thickness of 100 μm and a width of 600 mm. The obtained results are shown in Table 1.

(Example 2)
A film was formed under the same apparatus and conditions as in Example 1 except that the feed block described below was used. The used feed block includes one slit plate including 51 slits, and S (1), S (2),..., S (N),. S (1), S (2), S (3), S (4), S (48), S (49), S (50), S when S (50), S (51) The slit length of (51) is L, the width is 2.2 t, and the other slit shapes are the slit length L and the width t. The feed block is designed so that the resin A flows through the odd-numbered slit plates and the resin B flows through the even-numbered slits. The slit plate has a slit tip angle of 90 °, a contraction angle of 45 °, and a D / T of 100%. As a result, the formed film has 51 layers alternately laminated with A, B, A,..., A, B, A, and the layer thickness from the outermost layer on both sides of the film to the fourth layer on the inner layer side. Is about 10 times the Z layer thickness. The obtained film had a thickness of 100 μm and a width of 600 mm. The obtained results are shown in Table 1.

(Example 3)
A film was formed under the same apparatus and conditions as in Example 1 except that the feed block described below was used. The used feed block includes one slit plate including 51 slits, and S (1), S (2),..., S (N),. S (1), S (2), S (50), S (51) slit length is L, width is 2.2t, and S (50), S (51) The slit has a slit length L and a width t. The feed block is designed so that the resin A flows through the odd-numbered slit plates and the resin B flows through the even-numbered slits. As a result, the formed film has 51 layers alternately laminated with A, B, A,..., A, B, A, and the layer thickness from the outermost layer on both sides of the film to the fourth layer on the inner layer side. Is about 10 times the Z layer thickness. The slit plate has a slit tip angle of 90 °, a contraction angle of 45 °, and a D / T of 100%. As a result, the formed film has 51 layers alternately laminated with A, B, A,..., A, B, A, and the layer thickness from the outermost layer on both sides of the film to the fourth layer on the inner layer side. Is about 10 times the Z layer thickness. The obtained film had a thickness of 100 μm and a width of 600 mm. The obtained results are shown in Table 1.

Example 4
A film was formed under the same apparatus and conditions as in Example 1 except that the feed block described below was used. The used feed block includes one slit plate including 51 slits, and S (1), S (2),..., S (N),. The length of the slits of S (1), S (2), S (50), and S (51) is L, the width is 1.6t, and other than that when S (50) and S (51) are set. The slit has a slit length L and a width t. The feed block is designed so that the resin A flows through the odd-numbered slit plates and the resin B flows through the even-numbered slits. The slit plate has a slit tip angle of 90 °, a contraction angle of 45 °, and a D / T of 100%. As a result, the formed film has 51 layers alternately laminated with A, B, A,..., A, B, and A, and the X and Y layer thicknesses on both sides of the film are about the Z layer thickness. 4 times. The obtained film had a thickness of 100 μm and a width of 600 mm. The obtained results are shown in Table 1.

(Example 5)
A film was formed under the same apparatus and conditions as in Example 1 except that the feed block described below was used. The used feed block includes one slit plate including 201 slits, and S (1), S (2),..., S (N),. The length of the slits of S (1), S (2), S (200), S (201) is L, the width is 1.6t, and other than that when S (200), S (201) The slit has a slit length L and a width t. The feed block is designed so that the resin A flows through the odd-numbered slit plates and the resin B flows through the even-numbered slits. The slit plate has a slit tip angle of 90 °, a contraction angle of 45 °, and a D / T of 100%. As a result, the formed film has 51 layers alternately laminated with A, B, A,..., A, B, and A, and the X and Y layer thicknesses on both sides of the film are about the Z layer thickness. 4 times. The obtained film had a thickness of 100 μm and a width of 600 mm. The obtained results are shown in Table 1.

(Example 6)
A film was formed under the same apparatus and conditions as in Example 1 except that the feed block and merging apparatus described below were used. The feed block used comprises three slit plates, which have 267 slits. In each slit plate, S (1), S (2), ..., S (N), ..., S (266), S (267), S (1), S In (2), S (266), and S (267), the slit length is L and the width is 1.6 t, and the other slit shapes are the slit length L and the width t. The feed block is designed so that the resin A flows through the odd-numbered slit plates and the resin B flows through the even-numbered slits. The slit plate has a slit tip angle of 90 °, a contraction angle of 45 °, and a D / T of 100%. The merging device is installed subsequent to the feed block, and a total of 801 layers of laminar flow is produced by further laminating the resin laminated in 267 layers in each of the three slit plates of the feed block in the laminating direction. Device. As a result, the formed film has 801 layers alternately laminated with A, B, A,..., A, B, A, and the X and Y layer thicknesses on both sides of the film are about the Z layer thickness. 4 times. The obtained film had a thickness of 100 μm and a width of 600 mm. The obtained results are shown in Table 1.

(Example 7)
A film was formed under the same apparatus and conditions as in Example 4 except that polycarbonate (PC) [Taflon A2200 manufactured by Idemitsu Kosan Co., Ltd.] was used as the resin B after drying in air at 120 ° C. The obtained film had a thickness of 100 μm and a width of 600 mm. The obtained results are shown in Table 1.

(Example 8)
Polypropylene (PP) [Nobrene WF836DG3 manufactured by Sumitomo Chemical Co., Ltd.] was not dried as Resin A, and polyethylene terephthalate (PET) [F20S manufactured by Toray Industries, Inc.] was used as resin B after being dried under vacuum at 180 ° C. A film was formed using the same apparatus and conditions as in Example 4. The obtained film had a thickness of 100 μm and a width of 600 mm. The obtained results are shown in Table 1.

Example 9
A film was formed under the same apparatus and conditions as in Example 1 except that the feed block described below was used. The used feed block includes one slit plate including 51 slits, and S (1), S (2),..., S (N),. The length of the slits of S (1), S (2), S (50), and S (51) is L, the width is 1.6t, and other than that when S (50) and S (51) are set. The slit has a slit length L and a width t. The feed block is designed so that the resin A flows through the odd-numbered slit plates and the resin B flows through the even-numbered slits. Further, the slit tip angle of the slit plate is 180 °, the contraction angle is 45 °, and D / T is 100%. As a result, the formed film has 51 layers alternately laminated with A, B, A,..., A, B, and A, and the X and Y layer thicknesses on both sides of the film are about the Z layer thickness. 4 times. The obtained film had a thickness of 100 μm and a width of 600 mm. The obtained results are shown in Table 1.

(Example 10)
A film was formed under the same apparatus and conditions as in Example 1 except that the feed block described below was used. The used feed block includes one slit plate including 51 slits, and S (1), S (2),..., S (N),. The length of the slits of S (1), S (2), S (50), and S (51) is L, the width is 1.6t, and other than that when S (50) and S (51) are set. The slit has a slit length L and a width t. The feed block is designed so that the resin A flows through the odd-numbered slit plates and the resin B flows through the even-numbered slits. Further, the slit tip angle of the slit plate is 90 °, the contraction angle is 90 °, and D / T is 100%. As a result, the formed film has 51 layers alternately laminated with A, B, A,..., A, B, and A, and the X and Y layer thicknesses on both sides of the film are about the Z layer thickness. 4 times. The obtained film had a thickness of 100 μm and a width of 600 mm. The obtained results are shown in Table 1.

(Example 11)
A film was formed under the same apparatus and conditions as in Example 1 except that the feed block described below was used. The used feed block includes one slit plate including 51 slits, and S (1), S (2),..., S (N),. The length of the slits of S (1), S (2), S (50), and S (51) is L, the width is 1.6t, and other than that when S (50) and S (51) are set. The slit has a slit length L and a width t. The feed block is designed so that the resin A flows through the odd-numbered slit plates and the resin B flows through the even-numbered slits. The slit plate has a slit tip angle of 90 °, a contraction angle of 45 °, and a D / T of 150%. As a result, the formed film has 51 layers alternately laminated with A, B, A,..., A, B, and A, and the X and Y layer thicknesses on both sides of the film are about the Z layer thickness. 4 times. The obtained film had a thickness of 100 μm and a width of 600 mm. The obtained results are shown in Table 1.

(Comparative Example 1)
A film was formed under the same apparatus and conditions as in Example 1 except that the feed block described below was used. The used feed block includes one slit plate including 51 slits, and S (1), S (2),..., S (N),. When S (50) and S (51) are set, the slit length of S (1) and S (51) is L, the width is 1.6 t, and the other slit shapes are the length of the slit L. , The width is t. The feed block is designed so that the resin A flows through the odd-numbered slit plates and the resin B flows through the even-numbered slits. Further, the slit tip angle of the slit plate is 180 °, the contraction angle is 81 °, and D / T is 130%. As a result, the formed film has 51 layers alternately laminated with A, B, A,..., A, B, A, and the X layer thickness on both sides of the film is about 4 times the Z layer thickness. , Y has the same thickness as Z. The obtained film had a thickness of 100 μm and a width of 600 mm. The obtained results are shown in Table 1.

(Comparative Example 2)
A film was formed under the same apparatus and conditions as in Example 1 except that the feed block described below was used. The used feed block includes one slit plate, and the slit plate has 51 slits, and all the slits have a length L and a width t. The feed block is designed so that the resin A flows through the odd-numbered slit plates and the resin B flows through the even-numbered slits. Further, the slit tip angle of the slit plate is 180 °, the contraction angle is 81 °, and D / T is 130%. As a result, the formed film has 51 layers alternately laminated with A, B, A,..., A, B, A, and all the layers have a uniform thickness. The obtained film had a thickness of 100 μm and a width of 600 mm. The obtained results are shown in Table 1.

(Comparative Example 3)
A film was formed in the same apparatus and conditions as in Comparative Example 2 except that polycarbonate (PC) [Taflon A2200 manufactured by Idemitsu Kosan Co., Ltd.] was used as the resin B after drying in air at 120 ° C. The obtained film had a thickness of 100 μm and a width of 600 mm. The obtained results are shown in Table 1.

(Comparative Example 4)
A film was formed under the same apparatus and conditions as in Example 6 except that the feed block described below was used. The feed block used comprises three slit plates, which have 267 slits. All slits included in the feed block have a length L and a width t. The feed block is designed so that the resin A flows through the odd-numbered slit plates and the resin B flows through the even-numbered slits. Further, the slit tip angle of the slit plate is 180 °, the contraction angle is 81 °, and D / T is 130%. As a result, the formed film has 801 layers alternately laminated with A, B, A,..., A, B, A, and the thickness of all the layers becomes uniform. The obtained film had a thickness of 100 μm and a width of 600 mm. The obtained results are shown in Table 1.

Laminating apparatus and its components Detailed view of slit plate Slit structure Slit current section

Explanation of symbols

1: Side plate 2: Resin A supply unit 3: Slit unit 4: Resin B supply unit 5: Side plate 6: Laminating device 7: Resin A introduction port 8: Resin B introduction unit 9: Resin A liquid reservoir 10: Resin B liquid Reservoir 11: slit plate outlet 12: slit tip angle 13: center line 14 in slit stacking direction 14: contraction angle 14 ': contraction angle

Claims (13)

It is a laminated film formed by laminating 11 layers or more, each layer of the laminated film is made of a thermoplastic resin, and the layer thickness of the outermost layer (X) on at least one side is the layer thickness of the thinnest layer (Z) in the laminated film. A laminated film characterized in that it is 4 times or more and the layer thickness of the layer (Y) adjacent to X is also 4 times or more the layer thickness of Z. The laminated film according to claim 1, comprising at least thermoplastic resin A and thermoplastic resin B. The laminated film according to claim 2, wherein the difference in shear viscosity (shear viscosity S) at a shear rate of 15 s ⁻¹ at the same temperature between the thermoplastic resin A and the thermoplastic resin B is 100 Pa · s or more. The laminated film according to claim 1, wherein the shear viscosity S of the resin forming the outermost layer on at least one side of the film is lower than the shear viscosity S of the resin forming an adjacent layer measured at the same temperature. The laminated film according to claim 2, wherein an absolute value of a difference in SP value between the thermoplastic resin A and the thermoplastic resin B is 0.5 or more and 5 or less. The laminated film according to any one of claims 1 to 5, wherein the layer thickness of each layer from at least the outermost layer on one side of the film to the fourth layer on the inner layer side is at least four times the layer thickness of Z. The layer thickness of at least one outermost layer (X) and the layer thickness of the layer (Y) adjacent to the outermost layer is 1 μm or more and 30 μm or less, and the thinnest layer (Z) in the film has a layer thickness of 1 nm or more and 500 nm or less. The laminated film according to any one of claims 1 to 6. The laminated film according to claim 1, comprising a polyester resin. It is a feed block comprising one or more slit plates having a large number of slits, and the shape of the slit (Sx) positioned on at least one side of one of the slit plates and the slit positioned adjacent to Sx ( The shape of Sy) satisfies the following formulas 1 and 2 with respect to the shape of at least one of the slits (S) other than Sx and Sy in the same slit plate: Feed block.
4L (Sx) / t (Sx) ³ ≦ L ′ / t ′ ³ (Formula 1)
4L (Sy) / t (Sy) ³ ≦ L ′ / t ′ ³ (Formula 2)
L (Sx): Sx length (mm)
t (Sx): Sx width (mm)
L (Sy): Sy length (mm)
t (Sy): Sy width (mm)
L ′: Length of S (mm)
t ′: S width (mm) The feed block according to claim 9, wherein the slit tip angle is not less than 1 ° and not more than 120 °. 11. The feed block according to claim 9, wherein the feed block has a portion where the channel width decreases in the thickness direction, and the contraction angle is 15 ° or more and 80 ° or less. Breakage of the flow path between a straight line (A) connecting both wall surfaces passing through the ends of the two slits located on the outermost wall surface side of the slit plate and a straight line (B) connecting the positions where the flow path width becomes the shortest The feed block according to any one of claims 9 to 11, wherein the area (D) is within ± 20% of a square area (T) having A and B as the upper side and the bottom side. The manufacturing method of the laminated | multilayer film formed into a film using the feed block in any one of Claims 9-12.

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