JP2020082584A - Manufacturing apparatus and manufacturing method of multilayer body, and manufacturing method of multilayer film - Google Patents

Abstract

To more easily manufacture a multilayer body by combining a plurality of multilayer bodies each having a different thickness ratio between a multilayer laminate structure and a thick film layer from each other.SOLUTION: A manufacturing method of a multilayer body has: a first step for alternately laminating at least two types of molten resins to form a first molten laminate flow (1) with a multilayer laminate structure; a second step for laminating molten resin layers (3a, 3b) each provided by aligning, in the web crossing direction (V1), a plurality of different thickness regions (4a, 4b) each having a layer thickness different from each other, on at least one surface in the first molten laminate flow (1) in the laminating direction (V2), to form a second molten laminate flow in which each of the laminate regions of the plurality of different thickness regions (4a, 4b) in the first molten laminate flow (1) is made to a thickness different from each other; a third step for dividing the second molten laminate flow near a boundary (U) between the plurality of different thickness regions (4a, 4b) to form a plurality of third molten laminate flows, and combining the plurality of third molten laminate flows in each laminating direction to form a multilayer body.SELECTED DRAWING: Figure 1

Description

The present invention relates to a manufacturing apparatus and manufacturing method for a multilayer body, and a manufacturing method for a multilayer film.

A multilayer film obtained by stretching a multilayer sheet composed of a resin multilayer body has a specific wavelength of light due to structural optical interference between the layers that are exhibited by alternately laminating a large number of low refractive index layers and high refractive index layers. Can be an optical interference film that selectively reflects or transmits. In addition, such a multilayer film can reflect or transmit light over a wide wavelength range by gradually changing the film thickness of each layer along the thickness direction or by laminating films having different reflection peaks. Therefore, it is possible to obtain a high reflectance equivalent to that of a film using a metal, and it can be used as a metallic luster film or a reflection mirror. Further, it is known that by stretching such a multilayer sheet in one direction, it can be used as a polarizing reflection film that reflects only a specific polarized component, and can be used as a brightness improving member such as a liquid crystal display ( See, for example, Patent Document 1 below.

When manufacturing a multilayer film (multilayer body) as described above, an apparatus for increasing the number of layers by repeating mechanical operations in a composite flow has been used for a long time (for example, refer to Patent Document 2 below). Further, in the following Patent Documents 3 and 8, when a molten laminated flow (multilayer laminated structure) having a specific layer thickness distribution formed by a feed block is divided and combined using a square mixer to increase the number of layers, A device for changing the distribution ratio (area ratio of the flow path) of is disclosed. In this apparatus, a plurality of multilayer laminated structures having different thicknesses and having similar layer thickness distributions in proportion to the above distribution ratio are formed, and these multilayer laminated structures are combined in the laminating direction to manufacture a multilayer body. To do. Further, Patent Documents 4 and 5 below disclose an interface generation device having a plurality of replaceable or rotatable vanes for independently adjusting the flow rates of at least two or more tributaries.

Further, the following Patent Document 6 discloses an extrusion molding method of a multilayer polymer object for forming a protective boundary layer, and the following Patent Document 7 discloses a dope for a surface layer in which a distribution pin is provided at a confluence portion of a feed block. An apparatus for producing a multilayer film is disclosed which flows through a notch groove.

Japanese Patent Publication No. 11-508378 US Pat. No. 3,759,647 JP 2007-176154 A JP-A-4-278323 JP-A-4-278324 Japanese Patent Publication No. 8-501994 JP, 2005-279986, A JP-A-55-154128

The multilayer film may have a thick film layer for adjusting the total thickness, but after the thick film layer (molten resin layer) is laminated on the multilayer laminated structure (melt laminated flow), it is divided and joined by a square mixer. If the number of layers is increased by doing so, only a laminate having the same ratio of the thickness of the multilayer laminated structure and the thickness of the thick film layer can be obtained even if the distribution ratio in the square mixer is changed.

In order to connect the multilayer bodies having different thickness ratios of the multilayer laminate structure and the thick film layer, for example, two kinds of feed blocks are used to form a multilayer body of the multilayer laminate structure and the thick film layer, which are different from each other, and join. However, the device becomes large-scale.

The present invention more easily provides a multilayer body manufacturing apparatus and a manufacturing method, and a multilayer film for manufacturing a multilayer body by combining a plurality of laminated bodies having different thickness ratios of a multilayer laminated structure and a thick film layer. It is an object to provide a manufacturing method of

In order to solve the above problems, a manufacturing apparatus for a multilayer body according to a first aspect of the present invention is a multilayer laminating apparatus for alternately laminating at least two kinds of molten resins to form a first molten laminated flow of a multilayer laminated structure. A plurality of different thickness regions having different layer thicknesses are provided side by side in the laminating direction of the first melt-laminated flow and the web crossing direction orthogonal to the flow direction. A multi-layer feed block that forms a second melt-laminated flow in which the plurality of different-thickness regions in the first melt-laminated flow have different thicknesses by stacking on at least one surface in the stacking direction; The molten laminated flow is divided at the boundary portion of the plurality of different thickness regions to form a plurality of third molten laminated flows, and the plurality of third molten laminated flows are combined in respective laminating directions to form a multilayer body. And a split coupling device for

In the first aspect, first, in a multilayer laminating apparatus, at least two types of molten resins are alternately laminated to form a first molten laminated flow having a multilayer laminated structure. Next, in the multilayer feed block, the molten resin layer is laminated on at least one surface in the laminating direction of the first molten laminated flow to form the second molten laminated flow. In the molten resin layer, a plurality of different thickness regions having different layer thicknesses are provided side by side in the laminating direction of the first molten laminated flow and the web crossing direction orthogonal to the flow direction. In the second molten laminated flow formed by laminating the molten resin layer on the first molten laminated flow as described above, the laminated regions of the plurality of different thickness regions in the first molten laminated flow have different thicknesses. .. Next, in the split-coupling device, the second molten laminated flow is divided at the boundary portion (boundary or near the boundary) of the plurality of different thickness regions to form a plurality of third molten laminated flow. In the plurality of third melt-laminated flows (laminates), a multilayer laminated structure derived from the first melt-laminated flow and a resin layer derived from the plurality of different thickness regions (hereinafter, referred to as “thick film layer” in some cases). There is a difference in the thickness ratio from each other. Then, the plurality of third melt-laminated flows are combined in the respective stacking directions in the above split-coupling device to form (manufacture) a multilayer body. In the multilayer body manufactured in this manner, a plurality of laminated bodies having different thickness ratios of the multilayer laminated structure derived from the first molten laminated flow and the thick film layers derived from the plurality of different thickness regions are combined. It becomes the composition. Moreover, since it is not necessary to form and join a laminated body of a multilayer laminated structure and a thick film layer which are different from each other using two types of feed blocks, the above-mentioned multilayered body can be manufactured more easily.

In the manufacturing apparatus for a multilayer body according to the second aspect of the present invention, in the first aspect, the number of layers of the multilayer body is set within the range of 32 layers to 2009 layers.

In the second aspect, the number of layers of the multilayer body is set within the above range. Here, if the number of layers is less than 32 layers, there may be restrictions on the transmission performance or the reflection performance when the multilayer body is used as an optical interference film. If the number of layers is more than 2009, productivity and film Although the handling property may deteriorate, such a problem can be avoided in this aspect.

In the manufacturing apparatus for a multilayer body according to the third aspect of the present invention, in the second aspect, the at least two types of molten resins are laminated while passing through a large number of slits included in the multilayer laminating apparatus. The number of slits is set within the range of 15 to 501.

In the third aspect, at least two kinds of resins, which are the materials of the first molten laminated flow, are laminated by passing through a large number of slits included in the multilayer laminating apparatus. The number of these slits is set within the range of 15 to 501. Here, if the number of slits is less than 15, the number of layers of the multilayer body is small, so that there may be a restriction on the transmission performance or the reflection performance when the multilayer body is used as an optical interference film, and the number of slits is 501. If the number is larger than the number of devices, the size of the device becomes large, but such a problem can be avoided in this embodiment.

In the manufacturing apparatus for a multilayer body according to the fourth aspect of the present invention, in the third aspect, the width dimension of the slit is set within the range of 0.2 mm to 4.0 mm.

In the fourth aspect, a large number of slits through which at least two kinds of resins, which are materials for the first melt-laminated flow, pass are set to have a width dimension within a range of 0.2 mm to 4.0 mm. Here, if the width dimension of each slit is smaller than 0.2 mm, the flow rate of each layer is sensitive to the width dimension of each slit and high-precision processing is required, and the width dimension of each slit is less than 4.0 mm. If the width is wide, the pressure applied to the resin is insufficient and the flow rate distribution to the slits tends to vary, but such a problem can be avoided in this aspect.

In the manufacturing apparatus for a multilayer body according to the fifth aspect of the present invention, in the third or fourth aspect, the number of the plurality of slits is 31 or more, and at least 30 adjacent slits have the same flow rate. The length in the direction is formed so as to increase from one side to the other side in the stacking direction.

In the fifth aspect, by increasing the length of the slit as described above, a multilayer laminated structure in which the layer thickness gradually changes can be relatively easily provided in the multilayer body. It becomes possible to widen the reflection band when used as.

In the manufacturing apparatus for a multilayer body according to the sixth aspect of the present invention, in any one of the first to fifth aspects, the split/coupling device is a multiplier or a square mixer.

In the sixth aspect, the second melt-laminated flow formed by the multi-layer feed block is divided and combined by a multiplier or a square mixer. In the multiplier, the second molten laminated stream can be divided into at least two or more third molten laminated streams and combined. In the square mixer, the second molten laminated flow can be divided and combined into a small number of third molten laminated flows such as two. In addition, in the square mixer and the multiplier, the flow rate of each third molten laminated flow is independently adjusted so that the thickness of the multilayer laminated structure of each third molten laminated flow has a predetermined distribution ratio, if necessary. be able to. When the above distribution ratio is large, it means that there are two or more multilayer laminated structures having different layer thicknesses. As a result, it becomes possible to widen the reflection band when the multilayer body is used as an optical interference film.

A manufacturing apparatus for a multilayer body according to a seventh aspect of the present invention is the apparatus for manufacturing a multilayer body according to any one of the first to sixth aspects, wherein the split-joining device comprises two of the third melt-laminated layers from the splitting to the joining. There are two passages through which the flow flows, and the two passages are formed so that the flow rates of the two third melt-laminated flows become equal at least immediately before the joining.

According to the seventh aspect, in the split coupling device, two third melt-laminated flows from splitting to coupling flow through the two passages provided in the split coupling device. These two passages are formed so that the flow rates of the two third molten laminated flows become equal at least immediately before the joining. Thereby, the reflectance of the multilayer body configured by combining the two third molten laminated flows can be improved.

An apparatus for manufacturing a multilayer body according to an eighth aspect of the present invention is the apparatus for producing a multilayer body according to any one of the first to seventh aspects, wherein the multilayer feed block has a plurality of different thicknesses having different average heights in the stacking direction. The flow path has a layer thickness adjusting flow path provided side by side in the web crossing direction, and the molten resin layer passes through the layer thickness adjusting flow path, whereby the plurality of different thickness regions are formed in the molten resin layer. Is provided.

According to the eighth aspect, the multilayer feed block has a layer thickness adjusting flow channel in which a plurality of different thickness flow channels having different average heights in the stacking direction are provided side by side in the web crossing direction. Then, the molten resin layer is provided with a plurality of different thickness regions by passing through the layer thickness adjusting flow path. Thereby, a plurality of different thickness regions can be provided in the molten resin layer with a simple structure.

In the manufacturing apparatus for a multilayer body according to the ninth aspect of the present invention, in the eighth aspect, the multilayer feed block has a block main body and a pin member attached to the block main body, and the pin member includes A notch groove that forms a part of the layer thickness adjusting flow path is formed, and the notch groove has a plurality of different depth groove portions having different average depths in the stacking direction.

In the ninth aspect, the pin member attached to the block body of the multilayer feed block is formed with a cutout groove forming a part of the layer thickness adjusting flow path, and the cutout groove has an average depth in the stacking direction. Has a plurality of different depth groove portions different from each other. As a result, a plurality of different thickness channels having different average heights in the stacking direction are provided in the layer thickness adjusting channel. Therefore, it is possible to easily change the average heights of the plurality of different-thickness flow paths by replacing the above-mentioned pin member (notch groove). Adjustment of layer thickness and the like becomes easy. Further, for example, if the pin member is formed in a columnar shape, a plurality of types of the notched groove is formed in the outer peripheral portion of the pin member, and the pin member is rotatably attached to the block main body around the axis, The above adjustment can be easily performed by rotating the pin member.

In the manufacturing apparatus for a multilayer body according to a tenth aspect of the present invention, in the ninth aspect, the notch groove is formed such that boundaries of the plurality of different depth groove portions are stepped.

According to the tenth aspect, in the notch groove forming a part of the layer thickness adjusting flow path, the boundaries of the plurality of different depth groove portions are formed in a stepped shape (step shape). As a result, the boundaries between the plurality of different thickness regions provided in the molten resin layer are clarified, so that the layer thicknesses of the plurality of different thickness regions can be adjusted more precisely.

The method for producing a multilayer body according to an eleventh aspect of the present invention includes a first step of alternately laminating at least two kinds of molten resins to form a first molten laminated flow having a multilayer laminated structure, and a plurality of layers having different layer thicknesses. Layer of different thickness is provided side by side in the laminating direction of the first melt-laminated flow and in the web crossing direction orthogonal to the flow direction, and is laminated on at least one surface in the laminating direction of the first melt-laminated flow. By doing so, a second step of forming a second molten laminated flow in which the laminated regions of the plurality of different thickness regions in the first molten laminated flow have different thicknesses, and the second molten laminated flow is divided into the plurality of layers. A third step of forming a multi-layer body by dividing at the boundary of different thickness regions to form a plurality of third melt-laminated flows, and combining the plurality of third melt-laminated flows in each laminating direction; Have

In the eleventh aspect, first, in the first step, at least two types of molten resin are alternately laminated to form a first molten laminated flow having a multilayer laminated structure. Next, in the second step, the molten resin layer is laminated on at least one surface in the laminating direction of the first molten laminated flow to form the second molten laminated flow. In the molten resin layer, a plurality of different thickness regions having different layer thicknesses are provided side by side in the laminating direction of the first molten laminated flow and the web crossing direction orthogonal to the flow direction. In the second molten laminated flow formed by laminating the molten resin layer on the first molten laminated flow as described above, the laminated regions of the plurality of different thickness regions in the first molten laminated flow have different thicknesses. .. Next, in the third step, the second melt-laminated flow is divided at the boundary portion (boundary or near the boundary) of the plurality of different thickness regions to form a plurality of third melt-laminated flow. In the plurality of third melt-laminated flows (laminates), the thickness ratios of the multilayer laminated structure derived from the first melt-laminated flow and the resin layers (thick film layers) derived from the plurality of different thickness regions are different from each other. .. Then, in the above-mentioned third step, the plurality of third molten laminated flows are combined in each laminating direction to form (manufacture) a multilayer body. In the multilayer body manufactured in this manner, a plurality of laminated bodies having different thickness ratios of the multilayer laminated structure derived from the first molten laminated flow and the thick film layers derived from the plurality of different thickness regions are combined. It becomes the composition. Moreover, since it is not necessary to form and join a laminated body of a multilayer laminated structure and a thick film layer which are different from each other using two types of feed blocks, the above-mentioned multilayered body can be manufactured more easily.

In the method for producing a multilayer film according to the twelfth aspect of the present invention, the multilayer body formed by the method for producing a multilayer body according to the eleventh aspect is stretched to form a multilayer film.

In the twelfth aspect, the multilayer body formed by the method for producing a multilayer body of the eleventh aspect is stretched to form (manufacture) a multilayer film. This is a configuration in which a plurality of laminated bodies having mutually different thickness ratios of the derived multilayer laminated structure and the thick film layers derived from the plurality of different thickness regions are combined. Moreover, since it is not necessary to form and join a laminate of different multilayer laminated structures and thick film layers using two kinds of feed blocks, the above-mentioned multilayer film can be manufactured more easily.

As described above, according to the present invention, it is possible to more simply obtain a multilayer body and a multilayer film in which a plurality of laminated bodies having different thickness ratios of the multilayer laminated structure and the thick film layer are combined.

FIG. 6 is a perspective view showing a state immediately before a molten resin layer and a first molten laminated flow containing a large number of thin films are laminated in the method for manufacturing a multilayer body according to the embodiment of the present invention. FIG. 6 is an explanatory diagram for explaining an operation of dividing, branching, arranging, and joining the second molten laminated flow in the method for manufacturing a multilayer body according to the embodiment of the present invention. It is sectional drawing which shows an example of the cross section of the multilayer body obtained by the manufacturing method of the multilayer body which concerns on one Embodiment of this invention. It is explanatory drawing for demonstrating the ratio of the layer thickness used in the Example and the comparative example. It is a perspective view showing the composition of the manufacturing device of the multilayer body concerning one embodiment of the present invention. It is a top view showing the composition of the slit provided in the multilayer lamination device with which the manufacturing device is provided. It is sectional drawing which shows the partial structure of the multilayer feedblock with which the manufacturing apparatus is equipped. It is sectional drawing which shows the pin member provided in the same multilayer feedblock, and is a figure corresponding to the cross section along the GG line of FIG. It is sectional drawing which looked at the same pin member from the axial direction. It is sectional drawing which shows the layer thickness adjustment flow path (throttle part) provided in the same multilayer feedblock. It is sectional drawing which shows two passages provided in the split coupling apparatus with which the manufacturing apparatus is equipped. It is a conceptual diagram explaining the manufacturing method of the conventional multilayer body, and is a figure at the time of dividing and dividing|segmenting a 2nd molten laminated flow into 3 at different distribution ratios. It is sectional drawing which shows an example of the cross section of the multilayer body manufactured by the conventional manufacturing method of a multilayer body. It is sectional drawing which shows the diaphragm|throttle part provided in the multilayer feed block with which the manufacturing apparatus of the conventional multilayer body is equipped. In the method for manufacturing a multilayer body according to an embodiment of the present invention, a schematic diagram showing a list of thickness aspects of a thick film layer and a multilayer laminated structure when equally divided by a square mixer and when divided with a distribution ratio It is a figure. FIG. 6 is a schematic view showing a list of thickness modes of a thick film layer and a multilayer laminated structure in the case of equally dividing with a square mixer and dividing with a distribution ratio in a conventional method for producing a multilayer body. It is a diagram which shows the relationship between the groove width and groove depth of the notch groove|channel of the pin member used for the Example. It is a diagram which shows the relationship between the groove width and groove depth of the notch groove|channel of the pin member used for the comparative example. It is sectional drawing which shows the cross section of the central region of the multilayer film obtained by the Example and the comparative example.

Hereinafter, an apparatus and a method for manufacturing a multilayer body and a method for manufacturing a multilayer film according to an embodiment of the present invention will be described. The multilayer body manufacturing apparatus according to the present embodiment is an apparatus for performing the multilayer body manufacturing method and the multilayer film manufacturing method according to the present embodiment. In the method for manufacturing a multilayer body according to the present embodiment, first, in a first step, at least two types of molten resins are alternately laminated to form a first molten laminated flow having a multilayer laminated structure. Next, in a second step, a plurality of different thickness regions having different layer thicknesses are provided side by side in the laminating direction (thickness direction) of the first molten laminated flow and in the web crossing direction orthogonal to the flow direction. Is laminated on at least one surface of the first melt-laminated flow in the laminating direction to form a second melt-laminated flow in which the laminated regions of the plurality of different thickness regions in the first melt-laminated flow have different thicknesses. Form. Next, in a third step, the second melt-laminated flow is divided at the boundary portions of the plurality of different thickness regions to form a plurality of third melt-laminated flows, and the plurality of third melt-laminated flows are respectively laminated. Bonding in the directions to form (manufacture) a multilayer body. The first step, the second step, and the third step described above are respectively performed by the multilayer stacking device, the multilayer feed block, and the split coupling device provided in the multilayer body manufacturing apparatus according to the present embodiment. In addition, in the method for manufacturing a multilayer film according to the present embodiment, the multilayer body manufactured as described above is stretched to form a multilayer film.

[Outline of division and connection of multi-layer flow]
Hereinafter, a method for manufacturing a multilayer body according to this embodiment will be described with reference to FIGS. 1 and 2a. FIG. 1 shows a molten resin layer (3a) and a molten resin layer (3a), which are two molten resin layers (3), at both ends in the laminating direction (V2) of the first molten laminated flow (1) laminated in advance in a rectangular cross-section in multiple layers. FIG. 3 is a perspective view showing a state immediately before joining a layer (3b) to be melt-laminated. In the present embodiment, the molten resin layer (3a, 3b) is characterized by having a thick layer region (4b) and a thin layer region (4a) having different thicknesses in the laminating direction (V2) in the web crossing direction (V1). is there. The thick layer region (4b) and the thin layer region (4a) correspond to the "plurality of different thickness regions" in the present invention. In FIG. 1, SE indicates the boundary between the thin layer region (4a) and the thick layer region (4b).

By laminating the first molten laminated flow (1), the molten resin layer (3a) and the molten resin layer (3b), a second molten laminated flow (2) as shown in FIG. 2a is obtained. In this second molten laminated flow (2), the laminated region of the thin layer region (4a) in the first molten laminated flow (1) becomes the thick film portion (9a), and the thick layer region in the first molten laminated flow (1) The laminated region of (4b) becomes the thin film portion (9b). The thick film portion (9a) and the thin film portion (9b) have different thicknesses in the stacking direction (V2). 2A to 2C schematically show cross sections of the multilayer laminated structure in the first molten laminated flow (1), the thick film portion (9a) and the thin film portion (9b).

The second melt-laminated flow (2) is divided at the division boundary (U) in the division/branching operation (P1), so that the plurality of (here, two) third melt-laminated flows (5) are packets (5a). And packet (5b). In the following description, the packet (5a, 5b) may be referred to as the third melt-laminated flow (5). The division boundary (U) is a boundary portion (boundary or near the boundary) between the thick layer region (4b) and the thin layer region (4a) of the molten resin layer. Then, the third melt-laminated flow (5) branched by the rearrangement-coupling operation (P2) is re-formed so that the layer faces are parallel to each other so that the number of layers is increased and the layer faces are in contact with each other. It is arranged and combined to form a fourth molten laminated flow (6). The fourth molten laminated flow (6) corresponds to the "multilayer body" in the present invention. The combined fourth molten laminated flow (6) having a rectangular cross section has an outermost layer (7a) and an outermost layer (7b) on the surface in the laminating direction (V2), and the molten resin layers (3a, 3b) are It has a laminated intermediate layer (7).

Next, the overall configuration of the manufacturing apparatus (10) for a multilayer body according to this embodiment will be described with reference to FIG. As shown in FIG. 3, the multilayer body manufacturing apparatus (10) according to the present embodiment includes a multilayer stacking apparatus (20), a multilayer feed block (21), and a split coupling apparatus (31). .. The multi-layer laminating apparatus (20) includes, for example, a slit plate (SP) (see FIG. 4) having a large number of slits (S), and the multi-layer feed block (21) has, for example, a notch groove (24) formed therein. It is provided with a pin member (22) (see FIGS. 5, 6a and 6b). The split/coupling device (31) is, for example, a multiplier or a square mixer.

The first molten laminated flow (1) is formed by a multi-layer laminating device (20). The formed first molten laminated flow is laminated with the molten resin layers (3a, 3b) in the multilayer feed block (21) located downstream of the process, and becomes the second molten laminated flow (2). Splitting of the second melt-laminated flow (2) and joining of the plurality of third melt-laminated flows (5) formed by the division are performed by a split-coupling device (31). The fourth melt-laminated flow (6), which is a multilayer body obtained by merging, is then extruded from the die (33) to form a multilayer sheet (6a), and the multilayer sheet (6a) is stretched if necessary. By doing so, a multilayer film (6b) is obtained.

Hereinafter, each device and each process will be described in detail.
[Multilayer stacking device]
In the present embodiment, the first melt-laminated flow (1) is, for example, a multilayer laminating apparatus having a flat flow path partitioned by parallel plates described in Japanese Patent Laid-Open No. 2003-251675, and WO 2005/115719. It can be formed in accordance with a conventional method by using the slit plate described in 1) and the supply block having the slot described in Japanese Patent Publication No. 2002-509270.

Further, by the improved micro-layer multilayer composite product manufacturing apparatus described in Japanese Patent Publication No. 2005-523831, which melts and stacks flows, the flows to be molded are sequentially stacked and combined to form the first melt-laminated flow ( 1) may be formed.

(Tilt structure of the number of slits, gaps, and length)
The first melt-laminated flow (1) is a resin for the first layer and a resin for the second layer, which have passed through a large number of slits, from the viewpoints of manufacturing cost, optical design simplicity, and design of the multilayer laminating apparatus. Are preferably merged alternately at the exit of the slit.

The number of slits (S) included in the multilayer laminating device (20) is preferably set within a range of 15 to 501. It is more preferably within the range of 31 to 501, and even more preferably within the range of 101 to 351. When the number of slits (S) is less than 15, the number of layers of the multilayer body (6) and the multilayer film (6b) decreases, so that the transmission performance or reflection when the multilayer film (6b) is used as an optical interference film. Performance may be limited. On the other hand, when the number of slits (S) is more than 501, there is a problem that the device becomes large. In view of the number of slits (S) as described above, the number of layers of the multilayer body (6) is preferably set within the range of 32 layers to 2009 layers. It is more preferably within the range of 64 to 2009 layers, and even more preferably within the range of 204 to 1401 layers. When two more buffer layers are added to the multilayer body (6), the upper limit of the number of layers of the multilayer body (6) is 2011 layers.

If the width dimension w (see FIG. 4) of the many slits (S) through which the resin passes is too narrow, the flow rate of each layer reacts sensitively to the width dimension w, and high precision processing is required. If the width dimension w is too wide, the flow rate distribution to a large number of slits (S) tends to vary due to insufficient pressure applied to the resin, so it is preferable to set it within the range of 0.2 mm to 4.0 mm. More preferably, it is set within the range of 5 mm to 2.0 mm. The thickness t of the metal partition wall between the adjacent slits (S) is determined in the thickness range substantially similar to the width dimension w of the slits (S). Further, if the length L of the slit in the flow direction (V3) is short, it may not be rectified due to insufficient pressure, and if it is too long, the pressure increase may require a devise in the pressure resistant structure, or the accuracy of wire electric discharge machining may deteriorate. Therefore, it is preferably set in the range of 10.0 mm to 150.0 mm, and more preferably set in the range of 20.0 mm to 100.0 mm. The height of the slit (S) (dimension in the web crossing direction (V1)) is preferably set within the range of 10.0 mm to 50.0 mm at the resin outlet, and each layer is provided upstream of the slit (S). The height may be reduced within the range of 2.0 mm to 10.0 mm in order to largely change the film thickness, and fine holes may be used.

Further, as shown in FIG. 4, at least 30 adjacent slits (S) among the large number of slits (S) have a length L in the flow direction (V3) from one side to the other side in the stacking direction (V2). It is preferable that the slit (S) has a constant length or a reduced length in the remaining portion. By increasing the length of the slit (S) in this way, a multilayer laminated structure in which the layer thickness gradually changes can be realized relatively easily, and the reflection band of the optical interference film can be widened. If the ratio of (maximum slit length)/(minimum slit length) in the range in which the length L of the slit (S) increases is too small, the reflection wavelength band of the multilayer film (6b) becomes narrow, and if the ratio is too large, reflection occurs. Since it causes a decrease in the rate, it is preferably set in the range of 1.3 to 6.0, and more preferably set in the range of 1.5 to 4.0. In addition to this, a method for adjusting the layer thickness is to change the width in the stacking direction (V2) in the slit (S), change the height in the web crossing direction (V1) in the slit (S), or a multilayer stacking device ( It can be exemplified that a temperature distribution is given to 20) to change the melt viscosity of the resin.

It is preferable that the large number of slits (S) communicate with a manifold, which is a pressure equalizing chamber having a relatively large volume, and a predetermined stacking ratio can be easily obtained with high accuracy. The flow rate of the resin flowing through each slit (S) is generally inversely proportional to the length of the slit, and is distributed so as to be proportional to the cube of the gap of the slit (S). Therefore, a method of controlling the distribution of the layer thickness can be exemplified by adjusting the width dimension w and the length L of each slit (S) of the slit plate (SP) of the multilayer laminating apparatus (20).

[Multi-layer feed block (for lamination of molten resin layers)]
The multi-layer feed block (21), the pin member (22), and the cutout groove (24) will be described. Here, it is assumed that the respective layers constituting the first melt-laminated flow (1) are the first layer and the second layer, and the resin for the second layer is also the resin for the molten resin layer (3). Further, here, a case where the multilayer feed block (21) has a pair of pin members (22a, 22b) is illustrated.

When the resin for the second layer is used as the resin for forming the molten resin layer (3), the resin for the second layer is once branched in the multilayer laminating apparatus (20) shown in FIG. (3), and the other is alternately laminated with the resin for the first layer to form a multilayer, and the first molten laminated flow (1) is obtained. When the molten resin layers (3a, 3b) are laminated on both sides of the first molten laminated flow (1), the molten resin layer (3) is further branched into the molten resin layer (3a) and the molten resin layer (3b). , To a downstream multilayer feedblock (21).

In the multi-layer feed block (21) shown in FIG. 5, the molten resin layers (3a, 3b) flow through the two flow paths (FC2) in the direction of arrow a2, respectively, and join with the first molten laminated flow (1). Each of the pair of throttles (23) arranged immediately before is throttled (23a) and the throttle (23b), and the flow is adjusted once and adjusted to an appropriate flow. These narrowed portions (23a, 23b) correspond to the "layer thickness adjusting flow channel" in the present invention. These narrowed portions (23a, 23b) have a thin layer flow path (27a) and a thick layer (27a) having different average heights in the stacking direction (V2) with a dividing boundary (U) perpendicular to the web crossing direction (V1) as a boundary. It has a flow path (27b) (see FIG. 7). These narrowed portions (23a, 23b) are formed by the notch groove (24) formed in the pin member (22a) and the pin member (22b) which are the pair of pin members (22) arranged immediately before the confluence portion. Partly composed. The molten resin layers (3a, 3b) are adjusted to an appropriate flow as described above, and then joined and laminated with the first molten laminated flow (1) flowing in the direction of arrow a1 shown in FIG. Then, it becomes the second molten resin flow (2) and is guided downstream.

(Thick layer area and thin layer area)
In the present embodiment, the molten resin layer (3a, 3b) has a thick layer region (4b) and a thin layer region (4a). FIG. 1 is a schematic perspective explanatory view showing a state immediately before the molten resin layers (3a, 3b) and the first molten laminated flow (1) are merged. In comparison with FIG. 5, the molten resin layer (3a) is formed by the narrowed portion (23a) of the multilayer feed block (21) shown in FIG. 5, and the molten resin layer (3b) is formed by the narrowed portion (23b) shown in FIG. Is formed by. The first molten laminated flow (1) has a multilayer laminated structure in which thin films are laminated in advance in the laminating direction (V2), flows through the flow path FC1 shown in FIG. 5 in the direction of arrow a1, and then the molten resin It is laminated with the layers (3a, 3b) and guided to the outlet (25) as a second molten laminated flow (2). A schematic image of the cross section of the obtained second molten laminated flow (2) is shown in FIG. 2a.

In FIG. 1, the molten resin layer (3b) has a thin layer region (4a) and a thick layer region (4b) which have different thicknesses near the division boundary (U). Note that FIG. 1 exemplifies a case where the molten resin layer (3a) on the side opposite to the laminating direction (V2) also has a thin layer region (4a) and a thick layer region (4b). Due to the action of the thick layer region (4b) and the thin layer region (4a), in the second melt-laminated flow (2), the first melt-laminated flow (1) near the division boundary (U) as shown in FIG. 2a. Flow distributed in the web crossing direction (V1) occurs, and the thin film portion (9b) and the thick film portion (4b) corresponding to the thick layer region (4b) and the thin layer region (4a) of the molten resin layer (3a, 3b) respectively. 9a) is formed. The thin film portion (9b) and the thick film portion (9a) have the same number of layers, but the laminated states of the thin films are different from each other. As described above, it is possible to form a plurality of seeds (packets) having a multi-layered laminated structure in which the laminated states of thin films are different from each other. This finally broadens the application range of optical interference.

Further, FIG. 1 illustrates a case where the total thickness of the molten resin layer (3b) is thicker than the total thickness of the molten resin layer (3a). The molten resin layers (3a, 3b) are for the purpose of adjusting the total thickness of the multilayer film, for protecting the thin film layer of the multilayer laminated structure, for protecting the inclined structure of the thin film layer, and for preventing peeling at the layer interface. Can be applied and adjusted for the purpose of adjusting the curl of the multilayer film (6b). Also, for example, a mode in which either one of the molten resin layer (3a) and the molten resin layer (3b) is not present, that is, a mode in which the molten resin layer (3) is laminated only on one surface of the first molten laminated flow (1) It can be illustrated.

(Pin member)
The pin member (22) will be described with reference to FIGS. 5, 6a and 6b. Although the case where the narrowed portion (23) is formed by using the pin member (22) is described here, the narrowed portion is formed by using, for example, a layer thickness adjusting jig (choke bar) without using the pin member (22). It is also possible to form (23), and in this case as well, the notch groove (24) may be similarly formed.

FIG. 6a shows the cut surface of the pin member (22b) taken along the line GG of FIG. Further, FIG. 6b shows a sectional view of the pin member (22b) as seen from the axial direction. As shown in FIGS. 6a and 6b, the pin member (22b) according to the present embodiment is formed in a cylindrical shape. The pin (22b) is attached to the block body (26) which is the body of the multilayer feed block (21) so as to be rotatable about its own axis. A cutout groove (24) is formed in the outer peripheral portion of the pin member (22b). The notch groove (24) is composed of a groove portion (24a) and a groove portion (24b) which are distinguished by a division boundary (U). The groove portion (24a) and the groove portion (24b) correspond to the "plurality of different depth groove portions" in the present invention, and have different average depths in the stacking direction (V2).

In this embodiment, a plurality of (here, four) notch grooves (24) to notch grooves (241) to (244) are formed on the outer peripheral portion of the pin member (22b). The plurality of notch grooves (241) to (244) are arranged at equal intervals in the circumferential direction of the pin member (22b). The plurality of notch grooves (241) to (244) can have different average depths in the stacking direction (V2) in the groove portion (24a) and the groove portion (24b). Further, the pin member (22a) shown in FIG. 5 has basically the same configuration as the pin member (22b), and a plurality of (here, four) members are provided on the outer peripheral portion of the pin member (22a). Notch grooves (241) to (244) that are notch grooves (24) are formed. In the plurality of cutout grooves (241) to (244) formed in the pin member (22a) and the plurality of cutout grooves (241) to (244) formed in the pin member (22b), the groove portion A (24a). The average depth of the groove portion B (24b) in the stacking direction (V2) and the like can be different from each other. By rotating the pin members (22a, 22b) with respect to the block body (26), any one of the cutout grooves (241) to (244) is selectively drawn (23a, 23b). Form part of.

In the present embodiment, the notch groove (24) has a structure in which the average depth in the stacking direction (V2) is different from the dividing boundary (U). The notch groove (24) may have a different shape with the division boundary (U) as a boundary. The groove portion (24a) is a shallow groove whose average depth in the stacking direction (V2) is Ha, and the groove portion (24b) is a deep groove whose average depth in the stacking direction (V2) is Hb. In the narrowed portion (23b), the molten resin layer (3b) is regulated in the flow width in the web crossing direction (V1) by the groove width (W0) shown in FIG. 6a, and has an average depth Ha of the groove portions (24a, 24b). , Hb cause a difference in flow resistance around the division boundary (U), and a flow distributed in the web crossing direction (V1) is generated. As a result, a thin layer region (4a) passing through the groove (24a) and a thick layer region (4b) passing through the groove (24b) are formed in the molten resin layer (3b). Starting from this thickening and thinning action, the distribution ratio of the multilayer portion (multilayer laminated structure) of the first molten laminated flow (1) can be finally adjusted. Although FIG. 6a illustrates a case where the depth of the groove portions (24a, 24b) in the laminating direction (V2) is constant in the web crossing direction (V1), the depth of the groove portions (24a, 24b) is the same as that of the web. It may be partially or wholly continuously changed in the intersecting direction (V1).

FIG. 7 shows a flow path cross section of the throttle portion (23b). This flow path cross section has a thick layer flow path (27b) and a thin layer flow path (27a) having different average heights in the stacking direction (V2) at a division boundary (U) perpendicular to the web crossing direction (V1). This channel cross section is a region surrounded by the cutout groove (24) of the pin member (22b) and the block body (26) of the multilayer feed block. Although illustration is omitted, the flow passage cross section of the throttle portion (23a) is basically the same as the flow passage cross section shown in FIG. 7, and the thick layer flow passage (27b) and the thin layer flow passage (27a) are also shown. ) And. Further, in the present embodiment, the average height Hb of the thick layer channel (27b) is set to be the same as the average depth Hb of the groove portion (24b), and the average height Ha of the thin layer channel (27a) is set. Is set to be equal to the average depth Ha of the groove portion (24a). Further, in the present embodiment, the flow passage width W1 of the throttle portions (23a, 23b) is set to be the same as the groove width W0 of the groove portions (24a, 24b).

In the present embodiment, when the average height Ha of the thin layer flow channel (27a) and the average height Hb of the thick layer flow channel (27b) are made different from each other, the difference in height shown by the following equation (1) is used. Is preferably set within the range of 3.0% to 50.0%.
|Ha−Hb|/(Ha+Hb)×100 [%] (1)

When the ratio is less than 3.0%, the distribution effect of forming the thick and thin regions (4a) is weak, and when it is more than 50.0%, it becomes difficult to adjust the layer thickness to the design value. It is more preferable that the ratio is set within the range of 5.0% to 30.0%.

Further, in the present embodiment, the depths Ha and Hb of the groove portion (24a) and the groove portion (24b) are preferably changed in a stepped shape (step shape) as shown in FIG. 6a. As a result, the dividing boundaries of the molten resin layer (3) are sharpened, and the thick and thin regions can be formed more accurately. The step shape is preferably such that the ratio represented by the following formula (2) is in the range of 1.0% to 30.0%.
|H(Wa)−H(Wb)|/(H(Wa)+H(Wb))×100 [%]...(2)

If the ratio is less than 1.0%, the distribution effect to the thick and thin regions is weakened, and if it is more than 30.0%, it becomes difficult to adjust the layer thickness to the design value. It is more preferable that the ratio is set within the range of 3.0% to 20.0%. Here, as shown in FIG. 6a, the above H(Wa) is 20% (0.2) of the width (Wa) of the groove (24a), and the H(Wa) of the groove (24a) is apart from the dividing boundary (U). The depth is the depth H (Wb) of the groove (24b) at a position apart from the dividing boundary (U) by 20% (0.2) of the width (Wb) of the groove (24b). It is more preferable that the boundary between the groove portion (24a) and the groove portion (24b) is physically separated by fins or thin partition walls. The cross section of the groove (24) in FIG. 6a and the flow path cross section in FIG. 7 correspond to the GG cross section in FIG. This GG cross section is defined as a position where the cross sectional area is the smallest in a cross section substantially perpendicular to the flow direction of the molten resin layer (3) (see arrow a2 in FIG. 5). That is, the diaphragm portion (23).

The depth distribution of the notch groove (24), that is, the shape of the notch groove (24) can be a known one, and can be partially or entirely changed continuously in the web crossing direction (V1). For example, the notch shape of the layer thickness adjusting jig shown in FIGS. 3 to 6 of JP-A-7-241897 can be exemplified. In this embodiment, the average height of the “groove portion” is (area of groove portion)/(distance in web crossing direction), and the average height of “flow passage” is (cross-sectional area of flow passage)/(web crossing direction). Distance). Specifically, in FIG. 6a, the average height Ha of the groove portion (24a) is (the groove area of the groove portion (24a))/Wa, and the average height Hb of the groove portion (24b) is (the groove area of the groove portion (24b). )/Wb.

In the present embodiment, by rotating the pin members (22a, 22b), any one of the notch grooves (241) to (244) is formed in the flow passage cross section of the throttle portion (23a, 23b). It can be arranged selectively. This makes it possible to easily change the average heights of the thin layer channel (27a) and the thick layer channel (27b), so that the thin layer region (4a) and the thick layer provided in the molten resin layer (3) can be changed. The layer thickness and the like of the region (4b) can be easily (adjusted). Even when the pin members (22a, 22b) do not have the plurality of cutout grooves (24), the thin layer region (4a) and the thick layer region (4b) can be replaced by exchanging the pin members (22a, 22b). It is possible to adjust the layer thickness and the like.

[Explanation of split ratio operation]
In the multi-layer feed block (21), the molten resin layer (3) is joined to one end or both ends of the first melt-laminated flow (1), and then the second melt-laminated (2) is guided to the flow path having a rectangular cross section. As a result, a flow naturally occurs in the web crossing direction (V1), so that, as shown in FIG. 2a, the first molten laminated flow (1) corresponds to the thin layer region (4a) of the molten resin layer (3). A thick film portion (9a) is formed on the first molten laminated flow (1) corresponding to the thick layer region (4b) of the molten resin layer (3). It should be noted that FIG. 2a shows a case where the molten resin layers (3a) and (3b) join at both ends of the first molten laminated flow (1).

[Split-joining device (square mixer, multiplier)]
As shown in FIG. 3, in the present embodiment, a single split/coupling device (31) is arranged downstream of the multilayer feed block (21). The split melter (31) is used to split and join the second molten laminated flow (2). The split/coupling device (31) used for doubling or increasing the number of stacks mainly performs the split/branch operation (P1) and rearrangement/coupling operation (P2) shown in FIG. 2a, and is described in the background section. Square mixers and multipliers are preferred. You may arrange some of these in series. Thereby, for example, the reflectance of the obtained multilayer film can be uniformly increased.

In the case of a square mixer, the resin flow can be divided into a small number of about two and branched, and then rearrangement-bonded to easily increase (double) the number of laminated layers. Square mixers have a small number of branches, are compact in size, and often have short branch passages. The multiplier can be split into at least two or more tributaries. Multipliers often have long tributary paths. The square mixer and the multiplier can independently adjust the flow rate of each tributary so that the thicknesses of the two or more multi-layer portions have a predetermined distribution ratio, if necessary. The cross-sectional shape of the resin passage is preferably rectangular. In this distribution, by changing the area ratio or the passage length of the resin passages of each tributary, two or more multi-layered portions having different thicknesses that are approximately inversely proportional to the flow resistance according to the values can be obtained. When the distribution ratio is large, two or more multilayer portions having different layer thicknesses are provided, and the reflection band of the multilayer film can be a wide reflection band.

In this embodiment, the split coupling device (31) has two passages (31a) and two passages (31b) as shown in FIG. These two passages (31a, 31b) have two passages (31a, 31b) through which two third molten laminated flows (5) from division to joining flow in the direction of arrow a3. These two passages (31a, 31b) are preferably formed "symmetrically" so that the flow rates of the two third molten laminated flows (5) become equal at least immediately before the joining. In addition, "symmetry" in this case means that the dimensions of the cross-sectional area and the length of the passages (31a, 31b) are almost the same, and does not necessarily mean geometrical symmetry. , 31b) have the same cross-sectional area and the passages (31a, 31b) have the same total length. Alternatively, even if a combination of two passages (31a, 31b) having different cross-sectional areas and lengths is “symmetrical” if the total sum of the flow resistances of the passages (31a, 31b) is equal, the third fusion The laminated flow (5) can be bifurcated approximately equally. In these symmetrical passages (31a, 31b), the history of flow resistance applied to the resin becomes equal, so that the resin flow can be divided into two at equal flow rates. However, the thickness of the multilayer portion (multilayer laminated structure) of the obtained multilayer film may be slightly deviated from the design due to various disturbances. Therefore, in order to correct the deviation from the design value by measuring the laminated thickness of the obtained multilayer film, The flow resistance may be changed intentionally. In such a case, the passages whose flow distribution ratio is adjusted within the range of 0.90 to 1.10 are also two symmetrical passages. In the present embodiment, as an example, the two passages (31a, 31b) have a symmetrical shape in the coupling direction of the two third molten laminated flows (5) (here, the same direction as the laminating direction (V2)). Is formed in.

[Fourth molten laminated flow]
By the rearrangement-bonding operation (P2) shown in FIG. 2a, a plurality of third melt-laminated flows (5) are rearranged so that the layer surfaces are parallel to each other so that the number of layers is increased and the layer surfaces are in contact with each other. It is arranged and combined to form a fourth molten laminated stream (6). The thus obtained fourth molten laminated flow (6) is expanded in the web crossing direction (V1) if necessary, and is introduced into the downstream die (33) (see FIG. 3).

[Ratio of thickness of molten resin layers, ratio of thickness of multi-layer laminated structure]
FIG. 2b illustrates a cross section of the multilayer body (6) obtained in this embodiment. The cross section of the multilayer body (6) is the same as the cross section of the multilayer sheet (6a) or the multilayer film (6b) obtained in this embodiment. In this FIG. 2b, the second melt-laminated flow (2) is equally divided in the vicinity of the division boundary (U) by a square mixer, and two third melt-laminated flows (5a) and packet (5b) which are two third melt-laminated flows (5). Shows an example of creating and combining them.

The feature of this embodiment is that the ratio of the thickness of the molten resin layers (7a, 7b, 7c) to each other and the thickness of the multilayer laminated structure (9a, 9b) to each other due to the action of the thin layer region (4a) and the thick layer region (4b). This means that a multilayer sheet (6a) or a multilayer film (6b) having different ratios can be obtained. That is, it is possible to obtain a multilayer body (6) as shown in FIG. 2b, which cannot be obtained by the conventional method of division and connection. The multilayer body (6) shown in FIG. 2b satisfies any of the following expressions (3) to (5).
tb/t'a≠tB/tA (3)
t'b/ta≠tB/tA (4)
(Tb+t'b)/(ta+t'a)≠tB/tA (5)

On the other hand, in FIG. 9a, an example of a conventional method for producing a multilayer body (hereinafter, simply referred to as “conventional method”), that is, a molten resin layer (3a, 3b) is provided with a thin layer region and a thick layer region. An example of producing a fourth melt-laminated flow (6′) by dividing the unmelted second melt-laminated flow (2′) into three by three-branch multipliers having different distribution ratios and combining them Show. Further, FIG. 9b shows a detailed cross section of the multilayer body (6') obtained by the conventional method. As shown in FIG. 9b, this multi-layer body (6') is a combination of three third molten laminar streams, packet (5a), packet (5b) and packet (5c). Further, FIG. 10 shows an example of the narrowed portion (23') of the multi-layer feed block used in the above-mentioned conventional method in the same flow channel cross section as in FIG.

In the multilayer body (6') manufactured by the above-mentioned conventional method, the second molten resin layer (2) does not have a thin layer region and a thick layer region, or even if there is, a thick and thin region at the division boundary (U). Since there is no need to adjust the distribution and control the distribution action, the thickness ratio of the molten resin layers (7) and the multilayer laminated structure (9) of the packets (5a) to (5c) should be the same. is there. That is, this multilayer body (6′) satisfies the following equations (6) to (8) as shown in FIG. 9b.
ta/tc=t'a/t'c=tA/tC (6)
ta/t'b=t'a/tb=tA/tB (7)
tc/t'b=t'c/tb=tC/tB (8)

FIG. 11 shows a case where the splitting and combining device (31) divides the second molten laminated flow (2) into equal parts and when the distribution ratio is changed in the method for manufacturing a multilayer body according to the present embodiment. With respect to (in the case of equal division), modes of thickness of the obtained multilayer body (multilayer film) are listed. In addition, FIG. 12 shows the thicknesses of the multilayer bodies (multilayer films) obtained in the above-mentioned conventional method for the case where the second molten laminated flow is divided into equal parts and the case where the divided parts are not evenly divided. A mode of is shown in a list. 11 and 12, the cross sections of the molten resin layer and the multilayer laminated structure are shown in the same manner as in FIGS. 2a to 2c, 9a, and 9b, and the symbols of the molten resin layer and the multilayer laminated structure are shown. Omitted. Further, in FIGS. 11 and 12, tA and tB represent the thickness of the multilayer laminated structure, as in FIGS. 2b and 9b. As shown in FIG. 11 and FIG. 12, in the present embodiment, two packets (laminates) can be obtained in addition to those in which the ratio of the thickness of the molten resin layer and the ratio of the thickness of the multilayer laminated structure are different from each other. There is wide variation in the magnitude relationship between the thicknesses (tA and tB).

[Division boundary (U)]
The position of the dividing boundary (U) shown in FIGS. 6a and 7 passes through the midpoint of the groove width W0 or the midpoint of the flow passage width W1 when an equal division square mixer and multiplier are used, and Wa= Wb. On the other hand, in the case of using the unequal division square mixer and the multiplier having the distribution ratio, referring to the explanatory views of the conventional example of FIGS. ) Is internally divided into Wa:Wc:Wb, the layer thickness of the obtained multilayer film is measured, and the position of each division boundary (U) can be determined from the following equation (9) using it.
Wa:Wc:Wb=TA:TC:TB (9)
Here, TA, TB, and TC are the thicknesses of the multilayer laminated structure of the packet (5a), the packet (5b), and the packet (5c).

[Multilayer film]
The multilayer film produced according to the present embodiment has two or more multilayer laminated structures (hereinafter sometimes referred to as “multilayer part”) in which layers made of at least two kinds of resins are alternately laminated, and sandwiched between the multilayer parts. A multilayer film having an outermost layer on at least one surface of the multilayer film.

[Multilayer part]
In the multilayer portion, a first layer having a film thickness within the range of 10 nm to 1000 nm and a second layer having a film thickness within the range of 10 nm to 1000 nm have a total of 31 layers or more and are alternately laminated in the thickness direction. Preferred structures are Here, the film thickness refers to a physical thickness. By adjusting the optical thickness, which is the product of the film thickness and the refractive index of each layer, the reflection wavelength can be designed, and the reflection characteristics can be designed.

(Number of laminated layers)
In the multilayer portion, it is preferable that the first layer and the second layer are alternately laminated in total of 31 layers or more. When the number of stacked layers is less than 31, it becomes difficult to have the first layer and the second layer having various film thicknesses, and thus it becomes difficult to reflect light in a wide wavelength range. More specifically, for example, it becomes difficult to obtain a function as a metallic glossy film or a reflection mirror, and when used as a brightness enhancement member such as a liquid crystal display or a reflection type polarizing plate, the reflection characteristics of the reflection axis are It becomes difficult to obtain a high average reflectance over a wide wavelength range of 400 nm to 800 nm. Further, if the number of laminated layers is small, only a low reflectance can be obtained.

From the viewpoint of widening the corresponding wavelength range and the viewpoint of increasing reflectance, it is preferable that the number of laminated layers in one multilayer portion is large, preferably 50 layers or more, more preferably 100 layers or more, and further preferably 150 layers or more. is there. The “number of stacked layers in one multilayer portion” corresponds to the number of slits (S) described above. On the other hand, the total number of layers is preferably 2004 or less from the viewpoints of productivity and film handleability, but the number of layers may be further reduced from the viewpoint of productivity and handleability as long as desired reflection characteristics are obtained. For example, the number of layers may be 1002 or less, 502 or less, and 303 or less. The “total number of stacked layers” corresponds to the number of slits (S) described above, taking into consideration the number of divided and joined pieces. For example, when the number of slits (S) is 501 and the slits (S) are divided into two and joined in the stacking direction, the total number of stacks is 1002.

(Thickness distribution of multiple layers)
By having the first layer and the second layer having various thicknesses, the multilayer portion can reflect light in a wide wavelength range. For this purpose, in the multilayer portion, the film thicknesses of the first layer and the second layer increase from one end to the other end in the thickness direction. This increase may be an aspect in which the number of layers increases from one outermost layer to the other outermost layer in the multilayer portion, but in the multilayer structure, the number of layers is 80% or more, preferably 90% or more, More preferably, the thickness may be increased in 95% or more, and the thickness may be constant or decreased in the other portion.

(Tilt structure and reflectance)
The slope of the increase in the film thickness of the first layer and the second layer can reflect light in a wider wavelength range if the slope is moderate. In the first layer and the second layer, when the above film thickness increases along the thickness direction, the ratio of (maximum film thickness)/(minimum film thickness) is 1.2 or more and 8.0 or less. Preferably. If the ratio of (maximum film thickness)/(minimum film thickness) in the first layer or the second layer is small, the reflected wavelength range tends to be narrowed. For example, in applications such as a brightness enhancement member and a reflective polarizing plate, it is difficult to obtain a uniform average reflectance in a wide wavelength band of 400 nm to 800 nm for the reflection characteristics on the reflection axis, and the reflective polarization performance is It tends to be low. On the other hand, when the ratio of (maximum film thickness)/(minimum film thickness) is large, the reflection band becomes wider than 400 nm to 800 nm, whereby the reflectance at each wavelength tends to be small, and the reflectance in the necessary range is It may decrease. In the application of the brightness enhancement member or the reflection type polarizing plate, the reflectance on the reflection axis may be lowered, and the reflection polarization performance tends to be lowered. From such a viewpoint, the above ratio is more preferably 1.3 or more, further preferably 1.4 or more, particularly preferably 1.5 or more, and more preferably 6.0 or less, further preferably Is 5.0 or less, and particularly preferably 4.0 or less. In the multi-layer portion, it is desirable that the increase in the film thickness of the first layer and the second layer is monotonically increasing. The monotonous increase means that the number of layers of each layer within the range in which the film thickness tends to increase in the first layer or the second layer is divided into 5 equal parts, and the one outermost layer side goes to the other outermost layer side. It means that the average value of the film thickness in each equally divided area monotonically increases.

(Stretched film)
The multilayer film produced by the present embodiment may be a uniaxially stretched film or a biaxially stretched film in order to obtain desired optical characteristics. Hereinafter, the uniaxial stretching direction and the more stretched direction in the biaxial stretching may be referred to as the X direction. Further, the direction orthogonal to the X direction in the film plane may be referred to as the Y direction.

In the uniaxially stretched film, the difference in refractive index between the first layer and the second layer in the X direction is preferably 0.10 to 0.45. It is preferable that the difference in the refractive index in the X direction is in such a range because the reflection characteristics in such a direction can be efficiently improved and a high reflectance can be obtained with a smaller number of laminated layers.

Further, the difference in refractive index in the Y direction between the first layer and the second layer is preferably 0.05 or less. When the difference in the refractive index between the layers in the Y direction is in such a range, the reflectance in such a direction can be lowered, and the polarization performance is further enhanced in addition to the reflection characteristic in the X direction, which is preferable.

When used as a degree improving member such as a liquid crystal display or as a reflective polarizing plate, a high refractive index characteristic of 1.80 to 1.90 is preferable for the refractive index nX of the first layer in the X direction. When the refractive index in the X direction of the first layer is in such a range, it becomes easy to increase the difference in refractive index between the first layer and the second layer, and the reflective polarization performance can be further exhibited. The difference between the refractive index nY after uniaxial stretching in the Y direction and the refractive index nZ after uniaxial stretching in the Z direction is preferably 0.05 or less.

[Method for producing multilayer film]
A supplementary description will be given of the method for manufacturing the multilayer film according to the present embodiment. The manufacturing method described below is an example, and the present invention is not limited to this. Also, different aspects can be obtained with reference to the following.

The multi-layer sheet extruding device is mainly composed of an extruder, a gear pump, a filter, and a polymer pipe in order from the upstream side, and extrudes a multi-layered body in a molten state in a sheet form from a die according to the contents described above. And cast on a casting drum to obtain a multilayer sheet.

When the obtained multi-layered sheet is stretched to produce a multi-layered film, the multi-layered sheet has a film-forming machine axial direction (may be referred to as a longitudinal direction, a longitudinal direction or MD), or a direction orthogonal thereto in the film plane ( It is preferable that the film is stretched in at least one uniaxial direction (which may be referred to as a transverse direction, a width direction or TD) (the uniaxial direction is a direction along the film surface). The stretching temperature is preferably in the range of the glass transition temperature (Tg) to (Tg+20)° C. of the polymer of the first layer. By stretching at a temperature lower than the conventional temperature, the orientation properties of the multilayer film can be controlled to a higher degree.

The stretching ratio is preferably 2.0 to 7.0 times, and more preferably 4.5 to 6.5 times. The larger the draw ratio within this range, the smaller the variation in the refractive index of the individual layers in the first layer and the second layer due to the thinning due to stretching, and the more uniform the optical interference of the multilayer film in the planar direction. In addition, the difference in refractive index between the first layer and the second layer in the stretching direction becomes large, which is preferable. As the stretching method at this time, known stretching methods such as heating stretching with a rod-shaped heater, roll heating stretching, and tenter stretching can be used, but from the viewpoint of reduction of scratches due to contact with rolls and stretching speed, tenter stretching is performed. preferable.

Further, when the stretching treatment is also performed in a direction (Y direction) orthogonal to the stretching direction in the film plane and biaxial stretching is performed, it depends on the application, but when it is desired to have reflection polarization characteristics, 1. It is preferable that the stretching ratio is about 03 to 1.20 times. If the stretching ratio in the Y direction is further increased, the polarization performance may deteriorate.

In addition, the orientation characteristics of the multilayer film obtained by toe-out (re-stretching) in the stretching direction in the range of 5 to 15% while heat-setting at a temperature of (Tg) to (Tg+30)° C. after stretching are performed. It can be highly controlled.

When the coating layer is provided on the multilayer film in the present embodiment, the coating on the multilayer film can be carried out at any stage, but it is preferable to carry out in the manufacturing process of the multilayer film, with respect to the multilayer film before stretching. It is preferable to apply.

In the case of a multi-layer film used for applications such as a metallic luster film or a reflection mirror, it is preferable to use a biaxially stretched film. Good. The stretching ratio may be adjusted so that the refractive index and the film thickness of each of the first layer and the second layer may be adjusted so as to achieve desired reflection characteristics. In consideration of the refractive index of 2), it may be about 2.5 to 6.5 times in both the vertical and horizontal directions.

[resin]
In the present embodiment, the resin forming the multilayer film may be a thermoplastic polymer containing a stretchable polymer as a main component, and aromatic resins such as polyethylene terephthalate, polyethylene-2,6-naphthalate and polybutylene terephthalate may be used. Polyester, polyolefin such as polyethylene, polypropylene, polyvinyl such as polystyrene, polyamide such as nylon 6 (polycaprolactam), nylon 66 (poly(hexamethylenediamine-co-adipic acid)), fragrance such as bisphenol A polycarbonate Examples thereof include homopolymers such as group polycarbonates and polysulfones, or polymers containing these copolymers as main components. Examples of the copolymerization component include isophthalic acid copolymerized polyethylene terephthalate and 2,6-naphthalenedicarboxylic acid copolymerized polyethylene terephthalate. Among the above-mentioned thermoplastic polymers, aromatic polyesters, polyolefins and polyamides capable of molecular orientation by stretching are preferable, and polyethylene, which has excellent optical, mechanical and thermal properties when the molecules are biaxially oriented. 2,6-naphthalate is also preferred. These polymers may be blended with additives such as weathering agents, lubricants, antistatic agents and pigments, if necessary.

(Example)
Hereinafter, the present embodiment will be described with reference to examples, but the present embodiment is not limited to the examples shown below. The physical properties and characteristics in the examples were measured or evaluated by the following methods.

(1) Overall thickness of film A film sample is sandwiched between spindle detectors (K107C manufactured by Anritsu Electric Co., Ltd.) and 10 points of thickness are measured at different positions with a digital differential electronic micrometer (K351 manufactured by Anritsu Electric Co., Ltd.). Then, the average value was obtained and used as the film thickness.

(2) Thickness of each layer A multilayer film is cut out in the longitudinal direction of the film in the width direction of 2 mm and in the width direction of 2 cm in the vicinity of the center in the width direction of the film, fixed in an embedding capsule, and then wrapped with an epoxy resin (Epomount manufactured by Refinetech Co., Ltd.). Buried. The embedded sample was cut vertically with a microtome (ULTRACUT UCT manufactured by LEICA) in the width direction to obtain a 50 nm-thick thin film section. Observation and photographing were performed at a accelerating voltage of 100 kV using a transmission electron microscope (Hitachi S-4300), and the thickness of each layer was measured from the photograph.

Regarding layers having a thickness of more than 1 μm, the one existing inside the multilayer structure is the intermediate layer, the two layers existing on the outermost layer are the outermost layers, and the remaining two parts are the multilayer portions. The ratio of the total thickness of the multilayer structure of the total of 5 parts to 100% was calculated.

(3) Thickness Ratio In Examples and Comparative Examples, the multilayer film (6b) obtained as shown in FIG. 2b was evaluated by substituting the thickness constitution as shown in FIG. 2c. For example, when an evenly divided multiplier is used, the ratio of the thicknesses of the molten resin layers can be evaluated by the following equation (10).
(Ta+t'a)/(tb+t'b)=(50-tA)/(50-tB)...(10)
If the packet is not equally divided, the thickness ratio of each packet may be changed from 50:50 according to the division ratio.

[Production Example of First Layer] Polyester A
As the polyester for the first layer, dimethyl 2,6-naphthalenedicarboxylate, dimethyl terephthalate, and ethylene glycol are subjected to transesterification reaction in the presence of titanium tetrabutoxide, followed by polycondensation reaction to obtain an acid component. Copolymerized polyester in which 95 mol% of 2,6 naphthalenedicarboxylic acid component, 5 mol% of the acid component is terephthalic acid component, and glycol component is ethylene glycol component (intrinsic viscosity 0.64 dl/g) (o-chlorophenol , 35° C., and so on).

[Production Example of Second Layer] Polyester B
As the polyester for the second layer, dimethyl 2,6-naphthalenedicarboxylate, dimethyl terephthalate, and ethylene glycol and trimethylene glycol were subjected to transesterification reaction in the presence of titanium tetrabutoxide, and then subjected to polycondensation reaction. 50 mol% of the acid component is 2,6-naphthalenedicarboxylic acid component, 50 mol% of the acid component is terephthalic acid component, 85 mol% of the glycol component is ethylene glycol component, and 15 mol% of the glycol component is trimethylene glycol. A copolyester as a component (intrinsic viscosity 0.63 dl/g) was prepared.

[Example of production of multilayer film]
After drying the above-mentioned polyester for the first layer (referred to as polyester A) at 170° C. for 5 hours, and drying the above-mentioned polyester for the second layer (referred to as polyester B) for 8 hours at 85° C., respectively. 1, the second extruder, and heated to 300 ℃ to a molten state, then using the multilayer laminating apparatus (20) shown in FIG. 3, the polyester for the first layer into 139 layers with 139 slits Branched off. The polyester for the second layer is once branched, and one is further branched as a molten resin layer to form a molten resin layer (3a) and a molten resin layer (3b), and the other is made up of 138 pieces using a multilayer laminating apparatus (20). The slit branched into 138 layers. Here, a slit whose length was adjusted so that the film thickness of the first layer and the second layer increased along the thickness direction was used. In this way, the first melt-laminated flow (1) having the number of layers of 277 layers in which the first layer and the second layer are alternately laminated and the two melt resin layers (3a, 3b) are obtained, and the multilayer feed block (21 ). Then, in the multilayer feed block (21), the molten resin layers (3a, 3b) are laminated on the first molten laminated flow (1) through the throttle portions (23a, 23b) of FIG. Stream (2) was obtained. The narrowed portions (23a, 23b) are partially configured by pin members (22a, 22b) having a cutout groove (24). The relationship between the groove width and the groove depth in the notch groove (24) of these pin members (22a, 22b) is shown diagrammatically in FIG. 13a. In each notch groove (24), the dividing boundary (U) was at the midpoint of the groove width (W0), and the groove depth was stepwise. Table 1 below shows the ratio of the difference between the average depths Ha and Hb of each notch groove (24) and the stepwise ratio of the groove portions (24a, 24b).

The second molten laminated flow (2) obtained as described above is equally divided by a bifurcated and symmetric multiplier at a flow rate of about 1:1 and rearranged and combined to form two A fourth melt-laminated flow (6) having a total number of layers of 557 including one intermediate layer (7c) in which the molten resin layers (4a, 4b) are bonded and two outermost layers (7a, 7b), one for each surface layer. ) Got. After that, the laminated sheet was guided to a die (33) while maintaining the laminated state and cast on a casting drum to prepare a multilayer sheet (6a) having a total number of layers of 557 layers.

Then, the multilayer sheet (6a) was introduced into a tenter, stretched 6.0 times in the width direction at a temperature of 135°C, and heat-set at 150°C for 20 seconds to obtain a multilayer film (6b). The thickness of the obtained multilayer film (6b) was 75 μm. The results obtained are shown in Table 1 above. Further, FIG. 14 shows a cross section near the center of the multilayer film (6b) obtained in this example. In this example, the ratio of the thicknesses of the molten resin layers was 0.81, while the ratio of the thicknesses of the multilayer laminated structures was 1.14, and thus the ratios were different from each other. From this, it was confirmed that, according to this example, a multilayer film in which a plurality of laminates having mutually different thickness ratios of the multilayer laminated structure and the molten resin layer (thick film layer) were combined was obtained.

[Comparative example]
In the comparative example, a multilayer sheet was prepared in the same manner as this example except that the relationship between the groove width and the groove depth of the pin member (22a) and the pin member (22b) was changed as shown in FIG. 13b and Table 1 above. And a multilayer film having a thickness of 75 μm was obtained. The layer thickness of the thus obtained multilayer film is shown in Table 1 above. Further, in FIG. 14, the boundary between the molten resin layer and the multilayer laminated structure in the multilayer film obtained in the comparative example is shown by a two-dot chain line. When the ratio of the difference in groove depth of the pin members (22a, 22b) is small as in the comparative example, the distribution effect between the thick layer region and the thin layer region is weakened, so that the ratio of the thicknesses of the molten resin layers to each other and the multilayer laminated structure are The ratios of the thicknesses of the two were almost the same, and the ratio was close to 1.00. From this, it was confirmed that in the comparative example, only a laminate having a ratio of the thickness of the multilayer laminated structure to the thickness of the thick film layer was substantially the same.

In addition, in the said embodiment and an example, although the 2nd molten laminated flow (2) was divided into the packet (5a, 5b) which is two 3rd molten laminated flow (5), and was couple|bonded, it demonstrated. The present invention is not limited to this. That is, the second melt-laminated flow may be divided into three or more third melt-laminated flows and combined. In that case, the molten resin layer has a structure in which three or more regions having different thicknesses are provided side by side in the web crossing direction.

In addition, the present invention can be variously modified and implemented without departing from the scope of the invention. Further, it goes without saying that the scope of rights of the present invention is not limited to the above-described embodiments and examples.

1 1st molten laminated flow 2 2nd molten laminated flow 3a, 3b Molten resin layer (thick film layer)
4a Thin layer region 4b Thick layer region 5 Third molten laminated flow 6 Fourth molten laminated flow (multilayer body)
6a Multi-layer sheet 6b Multi-layer film 10 Multi-layer manufacturing device 20 Multi-layer laminating device 21 Multi-layer feed block 22 Pin member 23 Throttling part (layer thickness adjusting flow path)
24 Notch Grooves 24a, 24b Grooves (Different Deep Grooves)
27a thin layer flow channel 27b thick layer flow channel
31 division coupling device 32a, 32b passage U division boundary (boundary part)
V1 Web crossing direction V2 Laminating direction V3 Flow direction

Claims (12)

A multilayer laminating apparatus for alternately laminating at least two kinds of molten resins to form a first molten laminated flow having a multilayer laminated structure;
A plurality of different thickness regions having different layer thicknesses are arranged in the laminating direction of the first molten laminated flow and in a web crossing direction orthogonal to the flow direction, and the molten resin layer is provided in the first molten laminated flow. A multi-layer feed block forming a second melt-laminated flow in which the laminated regions of the plurality of different-thickness regions in the first melt-laminated flow have different thicknesses by laminating on at least one surface in the direction,
The second melt-laminated flow is divided at the boundaries of the plurality of different thickness regions to form a plurality of third melt-laminated flows, and the plurality of third melt-laminated flows are combined in respective laminating directions to form a multi-layer. A split coupling device for forming a body,
An apparatus for manufacturing a multi-layer body including. The multilayer body manufacturing apparatus according to claim 1, wherein the number of layers of the multilayer body is set within a range of 32 layers to 2009 layers. The at least two types of molten resin are laminated by passing through a large number of slits included in the multilayer laminating apparatus, and the number of the large number of slits is set within a range of 15 to 501. The apparatus for manufacturing the multilayer body according to claim 1 or 2. The manufacturing apparatus for a multilayer body according to claim 3, wherein a width dimension of the slit is set within a range of 0.2 mm to 4.0 mm. The number of the plurality of slits is 31 or more, and the at least 30 adjacent slits are formed such that the length in the flow direction increases from one side to the other side in the stacking direction. The manufacturing apparatus for a multilayer body according to claim 3 or 4, which is provided. The manufacturing apparatus for a multilayer body according to claim 1, wherein the split-coupling device is a multiplier or a square mixer. The split joining device has two passages through which the two third molten laminated flows from the split to the joining flow, and the two passages are at least immediately before the joining and the two third molten melts. The multilayer body manufacturing apparatus according to any one of claims 1 to 6, which is formed such that the flow rates of the laminated flow are equal. The multi-layer feed block has a layer thickness adjusting channel in which a plurality of different thickness channels having different average heights in the stacking direction are arranged side by side in the web crossing direction, and the layer thickness adjusting channel is The multilayer body manufacturing apparatus according to claim 1, wherein the plurality of different thickness regions are provided in the molten resin layer by passing the molten resin layer. The multilayer feed block has a block main body and a pin member attached to the block main body, the pin member is formed with a cutout groove forming a part of the layer thickness adjusting flow path, The manufacturing apparatus for a multilayer body according to claim 8, wherein the notch groove has a plurality of different depth groove portions having different average depths in the stacking direction. The said notch groove is a manufacturing apparatus of the multilayer body of Claim 9 in which the boundary of the said several depth groove part is formed in a step shape. A first step of alternately laminating at least two kinds of molten resins to form a first molten laminated flow of a multilayer laminated structure;
A plurality of different thickness regions having different layer thicknesses are arranged in the laminating direction of the first molten laminated flow and in a web crossing direction orthogonal to the flow direction, and the molten resin layer is provided in the first molten laminated flow. A second step of forming a second molten laminated flow in which the laminated regions of the plurality of different thickness regions in the first molten laminated flow have different thicknesses by laminating on at least one surface in the direction,
The second melt-laminated flow is divided at the boundaries of the plurality of different thickness regions to form a plurality of third melt-laminated flows, and the plurality of third melt-laminated flows are combined in respective laminating directions to form a multi-layer. A third step of forming the body,
A method for producing a multi-layer body having. A method for producing a multilayer film, comprising forming a multilayer film by stretching the multilayer body formed by the method for producing a multilayer body according to claim 11.