JP2014030938A - Multilayer extrusion molding apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus capable, when a multilayer film is manufactured by coextruding a molten resin based on a feed block scheme, of homogenizing thicknesses of the respective layers along the widthwise direction by controlling the thicknesses of the respective layers by a simple method.SOLUTION: In the provided multilayer extrusion molding apparatus for producing a multilayer film by merging, via a feed block, and extruding, from a monolayer die, plural molten resins, the feed block is constituted by a flow plate unit, a beak unit, and a die connection unit; the flow plate unit includes plural apertures into which the multiple molten resins are respectively charged; the beak unit includes an inner-layer flow path, an outer-layer flow path, and a merging path, provided as flow paths of the plural molten resins charged respectively into the plural apertures; the inner-layer flow path is a flow path having a rectangular cross section, whereas the outer-layer flow path is a flow path having a rectangular cross section and merging with the inner-layer flow path via the profile plane, whereas the merging path is a flow path having a rectangular cross section and provided by merging the inner-layer flow path and outer-layer flow path.

Description

  The present invention relates to a multilayer film extrusion molding apparatus, and more particularly to a multilayer extrusion molding apparatus using a feed block type coextrusion method in which a plurality of molten resins are joined together by a feed block and discharged from a single layer die.

  Thermoplastic resin films are used in various fields, and at that time, a plurality of properties suitable for the application are imparted. As a means for imparting these characteristics, a method of forming a multilayer film is used.

  Co-extrusion methods for producing a thermoplastic resin as a multilayer film include a multi-manifold method and a feed block method. In the multi-manifold system, a plurality of molten resins are spread in the width direction (the width direction refers to the width direction of the manufactured multilayer film, the same applies hereinafter) at each independent manifold in the die, and merged immediately before the die exit. To produce a film. Multi-manifold dies are complex in structure and expensive to manufacture, and dies must be prepared for each layer structure, film thickness and width.

  FIG. 1 shows a conventional coextrusion method using a feed block system. In the co-extrusion method using the feed block system shown in FIG. 1, three types of thermoplastic resins A, B, and C are supplied from the respective resin receiving ports 11a to 11c of the flow plate 10 and merged through the resin flow passages 12a to 12c. Extrusion width direction (perpendicular to the plane of the paper) by the same die 31 that produces the single layer film through the merged flow path 32 of the die connection portion 30 with the beak 20 merged at the point P. And a multilayer film (not shown) is formed by extrusion from the slit-shaped outlet 34.

  As described above, in the feed block method, a plurality of molten resins are merged in the feed block, and then developed in the width direction by a single manifold in the die to generate a film. The die used in a single layer can be used, and the layer configuration can be easily changed by changing the combination of feed blocks. On the other hand, in general, when a plurality of resins are merged in the feed block, the larger the ratio of the viscosity of each resin, the ratio of the flow velocity, and the ratio of the cross-sectional area, the more the disorder of the interface of the resin after merging occurs. It is known to be easy. In addition, after joining at the feed block, the manifold must be expanded to a width of about 10 times, and the distance to the discharge port of the die is long, so it is difficult to make the thickness of each layer uniform in the width direction. It is known that the longer the flow path after merging, the more enveloping phenomenon that each layer becomes uneven due to the difference in flow rate and melt viscosity.

  In Patent Document 1, by adjusting the flow path width of the resin with the notch of the layer thickness adjuster provided in the feed block, the flow rate is distributed to make the thickness distribution in the width direction of each layer of the multilayer film uniform. An extrusion apparatus is shown. In this method, it is necessary to change the shape of the layer thickness adjuster in accordance with the resin and the discharge conditions, and in addition, it is necessary to change the shape of the layer thickness adjuster for each layer when forming four or more layers. It is difficult to.

Patent Document 2 discloses an extrusion apparatus and a method for producing a multilayer film that optimizes the cross-sectional shape of the flow path at the confluence of the feed blocks to make the thickness distribution in the width direction of each layer of the multilayer film uniform. . However, since only the flow path shape of the resin of the outer layer can be controlled and applied, when the viscosity or flow rate of the intermediate layer is large, the flow rate distribution of the intermediate layer becomes convex and uneven thickness envelopment occurs.
Patent Document 3 discloses an apparatus that controls the temperature in the feed block to equalize the viscosity of each resin and reduce uneven thickness. Although the flow characteristics are controlled by adjusting the temperature, there is a limit to the adjustment of the flow characteristics by adjusting the temperature, and when the viscosity difference or flow rate ratio is large, only the temperature adjustment makes the flow profile of each layer uniform. It is difficult.

Japanese Patent Laid-Open No. 7-241897 JP 2002-225107 A Japanese Patent Laid-Open No. 11-309770

  Therefore, in view of the above problems, the present invention controls the thickness of each layer by a simple method when a multilayer film is manufactured from a die by co-extrusion of a molten resin by a feed block method. It is an object of the present invention to provide an apparatus for uniforming the thickness. In the present invention, the die mainly refers to a flat T die such as a coat hanger die, a fish tail die, or a straight manifold die.

Therefore, the invention of claim 1 of the present invention is
A multilayer extrusion molding apparatus for joining a plurality of molten resins in a feed block and extruding from a single layer die to produce a multilayer film,
The feed block is composed of a flow plate part, a beak part, and a die connection part,
The flow plate part has a plurality of openings into which a plurality of molten resins are charged,
The beak portion has an inner layer flow path that is a flow path of a plurality of molten resins introduced into the plurality of openings, an outer layer flow path, and a combined flow path.
The inner layer channel is a channel having a rectangular cross section,
The outer layer channel is a channel having a rectangular cross section that merges from the side surface with respect to the inner layer channel,
The merged channel is a channel having a rectangular cross section in which the inner layer channel and the outer layer channel are merged,
Between the inner layer flow path and the outer layer flow path, a plurality of movable partition walls are provided in the width direction (the width direction refers to the width direction of the film to be formed; the same applies hereinafter), and the plurality of partition walls. A first moving mechanism for individually moving the inner layer flow path in the thickness direction, the first moving mechanism adjusts the size and cross-sectional shape of the inner layer flow path,
A plurality of movable side wall members are provided in the width direction at positions facing the partition walls of the outer layer flow path, and the second side wall members individually move in the thickness direction of the outer layer flow path. A moving mechanism is provided, and the second moving mechanism adjusts the cross-sectional size and cross-sectional shape of the outer layer flow path,
The die connection part has a flow path connected to the combined flow path and the single-layer die.
A multilayer extrusion molding apparatus characterized by the above.

  The invention according to claim 2 is the multilayer extrusion molding apparatus according to claim 1, characterized in that a plurality of the beak portions are provided.

  The feed block provided in the multilayer extrusion molding apparatus according to the present invention can individually adjust the positions of the plurality of partition walls and side wall members in the width direction by the moving mechanism. The cross-sectional shape and the cross-sectional area can be adjusted, and as a result, molding defects can be reduced.

Diagram showing conventional coextrusion method using feed block method Schematic diagram of a feed block of a three-layer film extrusion apparatus illustrating one embodiment of the present invention. Schematic view of the beak of FIG. 2 as viewed from the upstream side in the flow direction. Schematic view of the flow plate part of Fig. 2 as viewed from the upstream side in the flow direction. 2 is a cross-sectional view taken along line B-B ′ in FIG. 2 showing the structure of the support. 3 is a cross-sectional view of A-A ′ in FIG. 3 showing the structure of the support. Schematic diagram of a feed block of a five-layer film extrusion apparatus exemplifying the second embodiment of the present invention Schematic view of the beak of FIG. 7 as viewed from the upstream side in the flow direction. Schematic view of the flow plate part of FIG. 7 as viewed from the upstream side in the flow direction.

  Embodiments of a multilayer extrusion molding apparatus according to the present invention will be specifically described below with reference to the drawings. As a first embodiment, a feed block of a three-layer film extrusion molding apparatus using three kinds of resins is shown in FIGS. FIG. 2 is a view showing a cross section of a feed block provided in the multilayer extrusion molding apparatus of the present invention. The feed block 4 includes a flow plate portion 10, a beak portion 20, and a die connection portion 30. The flow plate part 10 has introduction paths 11a to 11c having a round hole-shaped cross section which are a plurality of openings into which a plurality of molten resins are poured. The beak unit 20 includes an inner layer channel 25, outer layer channels 26 and 27, and a combined channel 28. The die connection part 30 has a flow path 32 connected to the combined flow path 28 and a single layer die (not shown).

  The inner layer flow path 25 is a flow path having a rectangular cross section, the outer layer flow paths 26 and 27 are flow paths having a rectangular cross section that merge from the side surface with respect to the inner layer flow path 25, and the combined flow path 28 is the inner layer flow path 25. And the outer layer channels 26 and 27 are merged, and the partition walls 21 and 23 between the inner layer channel 25 and the outer layer channels 26 and 27 are a plurality of partition walls movable by the first moving mechanism. And adjusting the cross-sectional size and cross-sectional shape of the inner layer flow path by moving the plurality of partition walls individually by the first moving mechanism in the thickness direction of the inner layer flow path indicated by the arrow 52. I can do it.

  By moving the plurality of side wall members 22, 24 provided at the position of the outer layer flow channel facing the partition walls 21, 23 by the second moving mechanism in the thickness direction of the outer layer flow channel indicated by the arrow 52, the outer layer flow channel The cross-sectional size and cross-sectional shape of 26 and 27 can be adjusted.

  The flow plate unit 10 will be described. FIG. 3 is a schematic view of the flow plate portion 10 as viewed from the upstream side in the flow direction. Fig.3 (a) is the flow plate part 10 in the case of connecting the three extruders 1-3 (FIG. 2). The introduction paths 11a to 11c opened in the shape of round holes to which the extruders 1 to 3 are connected are connected to the communication paths 12a to 12c while changing to a rectangular shape, and open to the beak side. Note that the number of extruders is not limited to three, and FIG. 3B shows a flow plate portion in the case of connecting two extruders. The introduction paths 11a and 11b to which the extruders 1 and 2 are connected open in a round hole shape, and the introduction path 11a is branched into two inside the flow plate portion 10 and is connected to the connection paths 12a and 12c while changing into a rectangle. The introduction path 11b is connected to the communication path 12b while changing to a rectangle, and opens to the beak side.

  The beak unit 20 will be described. As shown in FIG. 2, the beak portion 20 has a rectangular cross-section inner layer flow path 25 connected to the communication path 12b, a rectangular cross-section outer layer flow path 26 connected to the communication path 12a, and a communication path 12c. The outer layer channel 27 having a rectangular cross section connected to the inner layer channel 25, the outer layer channel 26, and the outer layer channel 27 are joined. Further, the beak portion 20 includes a partition wall 21 that can move in the thickness direction 52 of the inner layer flow path between the inner layer flow path 25 and the outer layer flow path 26, and a wall surface of the outer layer flow path 26. The side wall member 22 whose wall surface of the combined flow path 32 can move in the thickness direction 52 of the flow path, the partition wall 23 that partitions the inner layer flow path 25 and the outer layer flow path 27 and can move in the thickness direction 52 of the inner layer flow path, and the outer layer flow The wall surface of the path 27 and the wall surface of the combined flow path 32 have a side wall member 24 that can move in the thickness direction 52 of the flow path. The partition wall 21 and the partition wall 23 are moved and adjusted by supports 43 and 44, which are first moving mechanisms, respectively, and the side wall member 22 and the side wall member 24 are moved and adjusted by support bodies 41 and 42, which are second moving mechanisms. In this way, it is moved in the thickness direction of the flow path indicated by the arrow 52.

  FIG. 4 shows a view of the beak portion 20 viewed from the upstream side in the flow direction indicated by the arrow 51. The side wall member 22, the side wall member 24, the partition wall 21, and the partition wall 23 are divided into seven in the width direction of each flow path indicated by an arrow 53, and each divided piece is individually moved in the thickness direction indicated by an arrow 52. I can do it. Here, the number of divisions of the side wall member 22, the side wall member 24, the partition wall 21, and the partition wall 23 is not limited to seven, and may be any plural number. The support bodies 41 and 42 which are the second moving mechanisms pass through the beak housing 29 and fix the side wall members 22 and 24, and rotate the portions protruding from the beak housing 29, thereby rotating each side wall in the thickness direction 52. The positions of the members 22 and 24 can be adjusted.

  The supports 43 and 44 as the first moving mechanism have the same structure. As an example, a moving mechanism of the support 44 will be described. 5 is a cross-sectional view taken along the line B-B ′ of FIG. 4, and FIG. 6 is a cross-sectional view taken along the line A-A ′ of FIG. 4. The support body 44 includes an upper support body 444 that fixes the divided partition wall 231 from the upper surface of the partition wall 231, and a screw shaft 440 that is rotatably fixed inside the upper support body 444. The upper support 444 is disposed in the width direction 53 and is bent at a notch 290 provided in the beak housing 29 to fix the screw shaft 440. The screw shaft 440 has a male screw portion 441, and is screwed into a female screw portion 442 formed in the beak housing 29 and protrudes in the thickness direction 52 to the outside of the beak housing 29. The screw shaft 440 moves in the axial direction integrally with the partition piece 231 by the twisting operation of the screw shaft 440. In this way, the cross-sectional size and cross-sectional shape of the inner layer flow path 25 can be adjusted.

  As shown in FIG. 2, the die connection part 30 has a flow path 32 having a rectangular cross section, and connects the combined flow path 28 of the beak part 20 and the flow path of the die 31.

  As a second embodiment, FIG. 7 to FIG. 9 show a feed block of a five-layer film extrusion molding apparatus using two beaks. The feed block 4 shown in FIG. 7 includes a flow plate portion 10, a first beak portion 80, communication blocks 60 and 62, a second beak portion 70, and a die connection portion 30.

  The flow plate portion 10 is formed with, for example, round hole-shaped cross-section introduction paths 11a to 11e connected to five extruders (not shown), and communication paths 12a to 12e having a rectangular cross-section connected thereto. The beak portion 80 and the communication block 60 and the communication block 62 are connected. In order to explain the structure of the flow plate part 10, FIG. 8 shows a schematic view of the flow plate part 10 viewed from the upstream side in the flow direction when, for example, three extruders 1 to 3 are connected. The introduction paths 11a to 11c to which the extruders 1 to 3 are connected open in a round hole shape, and the introduction paths 11a and 11c are branched into two inside the flow plate portion 10 and change into a rectangular shape, respectively, and the connection paths 12a and 12c. The introduction path 11b is connected to the communication path 12b while changing to a rectangle, and opens to the beak side. The number of extruders is not limited to three, and in the case of a five-layer film using less than five extruders, the introduction path 11 is appropriately branched and connected to the communication paths 12a to 12e having a rectangular cross section. Use the flow plate section.

  The shape of the first beak portion 80 has the same structure as that described in the first embodiment, and is omitted.

The communication paths 12a to 12c of the flow plate section 10 are connected to the outer layer flow path 26, the inner layer flow path 25, and the outer layer flow path 27 of the first beak section 80, respectively, and the communication paths 12d and 12e of the flow plate section 10 are connected. Are connected to the communication path 61 of the communication block 60 and the communication path 63 of the communication block 62, respectively.

  The second beak portion 70 includes a rectangular cross-section inner layer flow path 75 connected to the combined flow path 28, a rectangular cross-section outer layer flow path 76 connected to the communication path 61, and a rectangular cross section connected to the communication path 63. An outer layer flow channel 77 having a cross-sectional shape, and a merge channel 78 having a rectangular cross section in which the inner layer flow channel 75, the outer layer flow channel 76, and the outer layer flow channel 77 merge. Further, the second beak portion 70 includes a partition wall 71 of the inner layer flow path 75 and the outer layer flow path 76, a wall surface of the outer layer flow path 76 and a wall surface of the combined flow path in the thickness direction 52 of the flow path. The movable side wall member 72, the inner layer channel 75 and the outer layer channel 77 are separated from each other, the partition wall 73 is movable in the thickness direction 52 of the inner layer channel, and the wall surface of the outer layer channel 77 and the combined channel wall surface are the thickness of the channel. And a side wall member 74 movable in the direction 52. The partition wall 71 and the partition wall 73 can be moved in the thickness direction 52 of the inner layer flow path 75 by supports 47 and 48 which are first moving mechanisms. Further, the side wall member 72 and the side wall member 74 are movable in the thickness direction 52 of the outer layer flow paths 76 and 77 by the support bodies 45 and 46 which are the second moving mechanisms.

  FIG. 9 shows the second beak portion 70 viewed from the upstream side in the flow direction indicated by the arrow 51. The side wall member 72, the side wall member 74, the partition wall 71, and the partition wall 73 are divided into seven in the width direction indicated by the arrow 53, and each of the divided pieces can be moved in the thickness direction indicated by the arrow 52. Here, the number of divisions of the side wall member 72, the side wall member 74, the partition wall 71, and the partition wall 73 is not limited to seven, and may be a plurality.

  The die connection part 30 has a flow path 32 having a rectangular cross section, and connects the combined flow path 78 of the second beak part 70 and the flow path of the die 31.

  In the second embodiment, the number of beaks is not limited to two, and a multilayer film of five or more layers can be formed by using three or more beaks in an overlapping manner.

  As described above, according to the multilayer extrusion molding apparatus provided with the feed block of the present invention, the cross-sectional size and cross-sectional shape of the flow path of the film of each layer can be adjusted, so that the thickness of each layer can be controlled. As a result, the film thickness in the width direction of the film can be made uniform.

DESCRIPTION OF SYMBOLS 1 ... Extruder 2 ... Extruder 3 ... Extruder 4 ... Feed block 10 ... Flow plate part 11 ... Introduction path 12 ... Introduction path 13 ... Introduction path 20 ... Beak part 21 ... Partition wall 22 ... Side wall member 23 ... Partition wall 24 ... Side wall member 25 ... Inner layer channel 26 ... Outer layer channel 27 ... Outer layer channel 28 .. Combined flow path 29... Beak housing 30. ··· Support 44 ··· Support 51 ··· Flow direction 52 ··· Thickness direction 53 ··· Width direction 60 ··· Communication block 61 ··· Communication path 62 ··· Communication block 63 Connecting path 70 ... Beak 71 ... Partition wall 72 ... Side wall member 73 ... Partition wall 74 ... Side wall member 75 ... The inner layer flow path 76 ... outer layer flow path 77 ... outer layer flow path 78 ... the combined channel 79 ... beak housing 290 ... notch

Claims (2)

A multilayer extrusion molding apparatus for joining a plurality of molten resins in a feed block and extruding from a single layer die to produce a multilayer film,
The feed block is composed of a flow plate part, a beak part, and a die connection part,
The flow plate part has a plurality of openings into which a plurality of molten resins are charged,
The beak portion has an inner layer flow path that is a flow path of a plurality of molten resins introduced into the plurality of openings, an outer layer flow path, and a combined flow path.
The inner layer channel is a channel having a rectangular cross section,
The outer layer channel is a channel having a rectangular cross section that merges from the side surface with respect to the inner layer channel,
The merged channel is a channel having a rectangular cross section in which the inner layer channel and the outer layer channel are merged,
Between the inner layer flow path and the outer layer flow path, a plurality of movable partition walls are provided in the width direction (the width direction refers to the width direction of the film to be formed; the same applies hereinafter), and the plurality of partition walls. A first moving mechanism for individually moving the inner layer flow path in the thickness direction, and the first moving mechanism adjusts the cross-sectional size and cross-sectional shape of the inner layer flow path,
A plurality of movable side wall members are provided in the width direction at positions facing the partition walls of the outer layer flow path, and the second side wall members individually move in the thickness direction of the outer layer flow path. A moving mechanism is provided, and the second moving mechanism adjusts the cross-sectional size and cross-sectional shape of the outer layer flow path,
The die connection part has a flow path connected to the combined flow path and the single-layer die.
A multilayer extrusion molding apparatus characterized by that.   The multilayer extrusion molding apparatus according to claim 1, comprising a plurality of the beak portions.

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