TWI816118B - Stretch film manufacturing equipment - Google Patents

Abstract

The first pressing part (50a) (first pressing area) formed by the central roller surface (50a) (first pressing area) of the contact roller (20a) (first roller) and the roller surface (21a) of No. 2 roller (21) (second roller) 60), press the first thermoplastic resin and the second thermoplastic resin injected from the T-shaped mold (24) (injection part). The second pressing part (61) formed by the end roller surface (50b, 50c) of the contact roller (the second pressing area) and the roller surface (21a) of the No. 2 roller (21) is lower than the first pressing part. (60) presses the second thermoplastic resin put into both ends of the first thermoplastic resin in the width direction. The formed film is cooled by the No. 2 roller (21) and the No. 3 roller (22) (third roller) constituting the cooling section (62), and is passed through the biaxial synchronous stretching device (14) (stretching section) The region holding the second thermoplastic resin extends the film in the moving direction and the width direction orthogonal to the moving direction.

Description

Stretch film manufacturing equipment

The present invention relates to a stretch film manufacturing device using a touch roller.

Since the thickness accuracy of films such as optical films is important, films are generally formed by contact roll molding.

Furthermore, the film formed by touch roll forming is held at both ends by clips and extends in the moving direction (longitudinal direction) and the width direction (lateral direction). At this time, since stress is concentrated on the ends of the film, cracks may occur and the film may break.

Therefore, for example, the stretched film manufacturing apparatus described in Patent Document 1 forms end multi-row films using polycarbonate resin or the like as reinforcement at the ends of the formed film.

[Prior technical literature]

[Patent Document]

[Patent Document 1] Japanese Patent No. 6377354

[Patent Document 2] Japanese Patent Application Publication No. 11-105131

However, at the contact portion of the touch roller, the formation state of the bulge (resin accumulation) is different at the end portion and the center portion of the film. Therefore, during the pressing step or the cooling and solidification step performed by the touch roller, the formation of the bulge (resin accumulation) occurs at the end portion. Wrinkled or roughened parts. When the film is stretched, stress is concentrated on the wrinkles or roughened portions thus generated, which may cause breakage. Therefore, in Patent Document 1, a trimming step (smoothing step) for removing uneven portions of both ends of the film is provided before stretching the formed multi-row film at the ends. However, performing the trimming step requires a lot of manpower and material resources, and there is a problem that productivity may be reduced due to film breakage caused by the trimming operation.

Furthermore, in Patent Document 2, open molding is performed in which the film is molded without pressing with rollers. However, films formed by open forming have problems in that thickness accuracy and surface smoothness are inferior to films formed by contact rollers.

The present invention was completed in view of the above, and an object thereof is to provide a stretched film manufacturing apparatus that can perform stretching without breakage, without wrinkles at the ends, and with high thickness accuracy without providing a trimming step before stretching. Manufacturing of membranes.

In order to solve the above-mentioned problems and achieve the object, the stretched film manufacturing apparatus of the present invention is characterized by having an input unit that inputs the melted first thermoplastic resin into the width direction center portion and the melted second thermoplastic resin. Put the first thermoplastic resin into two End side; 1st pressing part, which presses the first thermoplastic resin and the 2nd thermoplastic resin put in from the aforementioned input part in the first pressing area of the first roller and the second roller; the 2nd pressing part , in the second pressing area at both ends of the first pressing area before the first roller and the second roller, with a pressing force lower than that in the first pressing area, the second heat input from the input part is The plastic resin is pressed; and the cooling section is arranged after pressing the first thermoplastic resin and the second thermoplastic resin by the first roller and the second roller, passing the first thermoplastic resin and the second thermoplastic resin through the second roller. between the third roller on the opposite side of the first roller and cooled; and an extension portion holding both ends of the film formed of the first thermoplastic resin and the second thermoplastic resin cooled by the aforementioned cooling portion. The second thermoplastic resin region extends the film in the moving direction and the width direction orthogonal to the moving direction.

The stretched film manufacturing apparatus of the present invention has the effect of producing a stretched film that does not break, does not produce wrinkles at the ends, and has high thickness accuracy without providing a trimming step before stretching.

1a: Entrance

1b:Export

10: Stretch film manufacturing device

12: Pressing device (first pressing part, second pressing part, cooling part)

14: Biaxial synchronous extension device (extension part)

15L: Left side annular ring

15R: Right ring ring

20a, 20b, 20c, 20d: Contact roller (1st roller)

21:No.2 roller (2nd roller)

21a: Roller surface (first pressing area, second pressing area)

22:No.3 roller (3rd roller)

22a: Roller surface

23:Conveying roller

24: T-type mold (investment department)

25a, 25b, 25c: electric motor

26: Pressing pressure adjustment machine

27a, 27b, 27c: Rotation axis

28: Molten thermoplastic resin

28a: Acrylic resin (first thermoplastic resin)

28b, 28c: Polycarbonate resin (second thermoplastic resin)

30:Clip

31:Clip holding member

32,33: Drive sprocket

34: Electric motor

35: Clamp linkage mechanism

40: Reference track

41: Pitch setting track

50a, 50d: Center roller surface (first pressing area)

50b, 50c, 50e, 50f: End roller surface (second pressing area)

50d: Center roller surface (first pressing area)

60: 1st compression part

61: 2nd compression part

62: Cooling section

A: Preheating area

B:Extension area

C: Heat treatment area

K1,K2: arrow

S: membrane

Sa,Sb,Sc: area

X,Y,Z: axis

θ1, θ2: angle

FIG. 1 is an overall schematic diagram of the stretched film manufacturing apparatus of the first embodiment.

FIG. 2 is a side view of a pressing device included in the stretch film manufacturing apparatus of the first embodiment.

Figure 3 is a top view of the pressing part and the cooling part.

FIG. 4 is a plan view of the pressing part and the cooling part of the stretched film manufacturing apparatus according to the modified example of the first embodiment.

Figure 5 is a view of the pressing section and the cooling section of the stretched film manufacturing apparatus according to a modified example of the second embodiment. Top view.

FIG. 6 is a plan view of the pressing part and the cooling part of the stretched film manufacturing apparatus according to the modification of the second embodiment.

Hereinafter, embodiments of the stretched film manufacturing apparatus of the present disclosure will be described in detail based on the drawings. In addition, this invention is not limited by this embodiment. In addition, the structural elements of the following embodiments also include structural elements that can be replaced by those skilled in the art and can be easily imagined, or structural elements that are substantially the same.

(First Embodiment)

[Explanation of the schematic structure of the stretch film manufacturing equipment]

First, the overall structure of the stretched film manufacturing apparatus 10 of the first embodiment will be described using FIG. 1 . FIG. 1 is an overall schematic diagram of the stretched film manufacturing apparatus of the first embodiment.

The stretched film manufacturing apparatus 10 includes a pressing device 12 and a biaxial synchronous stretching device 14 . Furthermore, the stretched film manufacturing device 10 may also be equipped with a sequential stretching device that sequentially stretches the film in the longitudinal direction and the transverse direction. The following description is based on the case where the biaxial synchronous stretching device 14 is provided.

The pressing device 12 includes a T-die 24, a contact roller 20a, a No. 2 roller 21, a No. 3 roller 22, and a conveyance roller 23.

The T-shaped die 24 uses a thermoplastic resin that is melted by an extruder (not shown) as the material of the film. (hereinafter, referred to as molten thermoplastic resin) is put between the contact roller 20a and the No. 2 roller 21 that rotate with the roller surfaces in contact. Furthermore, the T-shaped mold 24 is an example of the input portion of the present disclosure.

The contact roller 20a is a substantially cylindrical roller, and presses the molten thermoplastic resin injected from the T-die 24 between the contact roller 20a and the No. 2 roller 21. The contact roller 20a is rotationally driven by an electric motor 25a controlled by a control device (not shown). In addition, the contact roller 20a is controlled by a control device not shown in the figure and has a pressing force adjuster 26 equipped with a cylinder and a piston controlled by hydraulic pressure, for example, to adjust the pressing force of the No. 2 roller 21. In addition, the touch roller 20a is an example of the 1st roller of this disclosure. In addition, the detailed shape of the contact roller 20a will be described later (refer to FIG. 4).

A heat medium (hereinafter referred to as a heat medium) such as cooling water or cooling oil circulates inside the contact roller 20a, and the molten thermoplastic resin is cooled while being pressed between the contact roller 20a and the No. 2 roller 21.

The No. 2 roller 21 is a cylindrical roller, and presses the molten thermoplastic resin injected from the T-die 24 by sandwiching it between the roller 20 and the contact roller 20 a. The No. 2 roller 21 is rotationally driven by an electric motor 25b controlled by a control device (not shown). In addition, No. 2 roller 21 is an example of the 2nd roller of this disclosure.

A heat medium such as cooling water or cooling oil circulates inside the No. 2 roller 21, and the molten thermoplastic resin is cooled while being pressed between the contact roller 20a and the molten thermoplastic resin.

The No. 3 roller 22 is a cylindrical roller, and a heat medium such as cooling water or cooling oil is circulated inside. The No. 3 roller 22 is arranged on the opposite side of the contact roller 20 a with the No. 2 roller 21 interposed therebetween (see FIG. 2 ). The No. 3 roller 22 cools the molten thermoplastic resin formed into a film by sandwiching it between the No. 2 roller 21 and the No. 2 roller 21 . The No. 3 roller 22 is rotationally driven by an electric motor 25c controlled by a control device (not shown). In addition, No. 3 roller 22 is an example of the 3rd roller of this disclosure.

The conveying roller 23 is a cylindrical roller, and the moving direction of the pressed and cooled film S is directed toward the inlet 1 a of the biaxial synchronous stretching device 14 .

The biaxial synchronous stretching device 14 has an annular ring 15R and an annular ring 15L symmetrically on the left and right sides in a plan view. The annular ring 15R and the annular ring 15L have a plurality of clips 30 for holding the film S. The film S to be stretched is fed in from the inlet 1a, and is discharged from the outlet 1b in a stretched state. In addition, when viewed from the inlet 1a side of the membrane S to be stretched, the annular ring on the right side is called the right annular ring 15R, and the annular ring on the left side is called the left annular ring 15L. In addition, the film S is, for example, a resin film having thermoplasticity. In addition, for the convenience of subsequent explanation, the coordinate system XYZ shown in FIG. 1 is set. The X-axis is the axial direction of the contact roller 20a, the No. 2 roller 21, the No. 3 roller 22, and the conveyance roller 23, and the width direction of the film S. The Y axis is the moving direction of the film S in the biaxial synchronous stretching device 14 . The Z axis is the direction orthogonal to the X axis and Y axis. Furthermore, the biaxial synchronous extending device 14 is an example of the extending portion of the present disclosure.

The clips 30 are respectively installed at one end of the rectangular clip holding member 31 in the longitudinal direction (a position facing each other between the inlet 1a and the outlet 1b). That is, a pair of opposing clips 30 is arranged at both ends in the width direction of the film S, which is the object to be stretched, and functions as a holding device for holding the object to be stretched.

The clip holding member 31 is guided by the reference rail 40 and circulates in a circular motion. The right annular ring 15R circulates in the clockwise direction, and the left annular ring 15L circulates in the counterclockwise direction. Specifically, a driving roller (not shown) of the clip holding member 31 is selectively engaged with the driving sprockets 32 and 33 to move each clip holding member 31 along the circuit path. That is, the driving sprockets 32 and 33 are selectively engaged with the driving rollers of each clip holding member 31 and are rotationally driven by the electric motor, thereby imparting force to the clip holding member 31 so that each clip holding member 31 moves along the circuit. The power of path shifting. Specifically, the two driving sprockets 33 are driven by the rotational driving force of the electric motor 34 that is reduced by a speed reducer (not shown). The two driving sprockets 32 are respectively driven by the rotational driving force of an electric motor (not shown) that is decelerated in the opposite direction by two speed reducers (not shown).

When the distance between the reference rail 40 of the right annular ring 15R and the reference rail 40 of the left annular ring 10L becomes larger, the film S extends in the lateral direction (X-axis direction).

Adjacent clip holding members 31 are connected to each other by a clip linkage mechanism 35 including a plurality of links. The clip link mechanism 35 is guided by the pitch setting rail 41 and circulates in an annular manner together with the clip holding member 31 .

The clip link mechanism 35 sets the distance between adjacent clip holding members 31 (hereinafter referred to as the clip pitch) based on the distance between the reference rail 40 and the pitch setting rail 41 . The larger the clip pitch is, the more the film S extends in the direction orthogonal to the width direction, that is, the longitudinal direction (Y-axis direction) in which the clip holding member 31 moves. In addition, FIG. 1 shows a state in which the film S fed from the inlet 1a extends in the vertical and horizontal axis directions. In order to make it easier to understand the drawings, the film S is depicted as being discontinuous. In fact, the film S is continuous from the inlet 1a to the outlet 1b.

The biaxial synchronous stretching device 14 is provided from the inlet 1a side of the film S to the outlet 1b side: a preheating zone A, a stretching zone B, and a heat treatment zone C.

In the preheating zone A, the distance (separation distance) between the reference rails 40 of the left annular ring 15L and the right annular ring 15R is set to be equivalent to the initial width of the lateral extension, and the left annular ring 15L and the right annular ring 15R are throughout the entire area. arranged parallel to each other. Furthermore, in the left annular ring 15L and the right annular ring 15R, the distance between the reference rail 40 and the pitch setting rail 41 is equivalent to the longitudinal extension initial pitch.

In the extension zone B, from the side of the preheating zone A toward the heat treatment zone C, the separation distance between the left annular ring 15L and the right annular ring 15R gradually increases, and the left annular ring 15L and the right annular ring 15R are not configured in parallel. The separation distance between the left annular ring 15L and the right annular ring 15R of the extension zone B is set to be equivalent to the initial width of the lateral extension at the extension start end (the connection end with the preheating zone A), and at the extension end end (with the heat treatment zone C) The connecting end) is set to be equivalent to the final width of the lateral extension. That is, in the extension zone B, from the side of the preheating zone A toward the heat treatment zone C, the distance between the reference track 40 of the left annular ring 15L and the reference track 40 of the right annular ring 15R gradually expands. The distance between each reference rail 40 at the extension start end (the connection end with the preheating zone A) is equivalent to the initial width of the lateral extension, and at the extension end end (the connection end with the heat treatment zone C) is equivalent to the final width of the lateral extension.

Furthermore, in the extension zone B, from the side of the preheating zone A toward the heat treatment zone C, the distance between the reference rail 40 and the pitch setting rail 41 of the left annular ring 15L gradually decreases. Moreover, the right ring The distance between the reference rail 40 and the pitch setting rail 41 of the shape ring 15R also gradually decreases. The distance between the reference rail 40 and the pitch setting rail 41 is equivalent to the initial pitch of longitudinal extension at the extension start end (the connection end with the preheating zone A), and is equivalent to the longitudinal extension at the extension end end (the connection end with the heat treatment zone C). final pitch. That is, the biaxial synchronous stretching device 14 simultaneously extends the film S longitudinally and transversely in the stretching area B.

In the heat treatment zone C, the separation distance between the left annular ring 15L and the right annular ring 15R is set to be equivalent to the final width of the lateral extension, and the left annular ring 15L and the right annular ring 15R are arranged parallel to each other throughout the entire area. In addition, the distance between the reference rail 40 and the pitch setting rail 41 is set to correspond to the final pitch of the longitudinal extension, and the reference rail 40 and the pitch setting rail 41 are arranged parallel to each other throughout the entire area.

[Explanation of the detailed structure of the pressing device]

Next, the detailed structure of the pressing device 12 for pressing molten thermoplastic resin will be described using FIGS. 2 and 3 . FIG. 2 is a side view of a pressing device included in the stretch film manufacturing apparatus of the first embodiment. Figure 3 is a top view of the pressing part and the cooling part.

The molten thermoplastic resin 28 injected from the T-die 24 toward the Z-axis downward direction has a multi-row structure in which acrylic resin 28a is arranged in the center and polycarbonate resin 28b is arranged in both ends, as shown in FIG. 3 .

The injected molten thermoplastic resin 28 enters the contact roller 20a that rotates clockwise around the rotation axis 27a (arrow K1 direction in FIG. 2), and rotates counterclockwise around the rotation axis 27b (arrow K2 direction in FIG. 2). The contact surface of No. 2 roller 21. The contact roller 20a is pressed toward the No. 2 roller 21 by the pressing force adjuster 26, so the molten thermoplastic resin 28 is sandwiched between the contact roller 20a and the No. 2 roller 21 and pressed.

Furthermore, the molten thermoplastic resin 28 is cooled by the heat medium circulating inside the contact roller 20a and the heat medium circulating inside the No. 2 roller 21. The heat medium is controlled at a temperature near the glass transition temperature of the molten thermoplastic resin 28 . Furthermore, by setting the temperature of the heat medium circulating inside the No. 2 roller 21 to be slightly higher than the temperature of the heat medium circulating inside the contact roller 20a, the heat of fusion pressed by the contact roller 20a and the No. 2 roller 21 The plastic resin 28 moves in the positive direction of the Y-axis along with the surface (roller surface) of the No. 2 roller 21 having a higher temperature.

Thereafter, the molten thermoplastic resin 28 is sandwiched between the No. 2 roller 21 and the No. 3 roller 22 rotating clockwise (arrow K3 direction) about the rotation axis 27c, and is cooled. Furthermore, since the temperature of the heat medium circulating inside the No. 3 roller 22 is set higher than that of the heat medium circulating inside the No. 2 roller 21, it is sandwiched between the No. 2 roller 21 and the No. 3 roller 22. The molten thermoplastic resin 28 (film S) will move in the positive direction of the Y-axis along with the surface (roller surface) of the No. 3 roller 22 with a higher temperature.

Through each of the above steps, the film S is formed from the injected molten thermoplastic resin 28 .

Furthermore, the stretched film manufacturing apparatus 10 of this embodiment manufactures an end multi-row film in which both ends in the width direction of the film S are formed of polycarbonate resin and the center portion in the width direction is formed of acrylic resin. Generally speaking, polycarbonate resin is stronger than acrylic resin. Therefore, even if the biaxial synchronized stretching device 14 is provided with, the clamps 30 hold both width-direction ends of the formed film S formed of polycarbonate resin in the moving direction and width direction of the film S. Even when extending upward, the film S will not be broken and can be extended in the longitudinal and transverse directions at a specific magnification.

[Explanation of the function of the pressing device]

Next, the function of the pressing device 12 will be described using FIG. 3 . The center roller surface 50a of the center part of the roller surface of the contact roller 20a is convexly processed. Generally speaking, when pressing a roller, the pressing force may decrease due to the deflection of the roller itself. In order to make the pressing force uniform, processing is performed to thicken the center portion of the roller relative to the end portion of the roller. This is convex processing. Then, the cross section of the roller formed by convex processing including the rotation axis takes a curved shape such as a quadratic curve, a quadratic curve, a sinusoidal curve, etc. which are called convex curves. Then, the center roller surface 50a is pressed against the No. 2 roller 21 having the cylindrical roller surface 21a, and the first pressing part 60 is formed. In this embodiment, a part of the acrylic resin 28a and the polycarbonate resin 28b is pressed by the center roller surface 50a of the contact roller 20a and the roller surface 21a of the No. 2 roller 21 at the first pressing part 60. Furthermore, the central roller surface 50a and the roller surface 21a facing the central roller surface 50a are an example of the first pressing area of the present disclosure.

In addition, the end roller surfaces 50b and 50c on both end sides of the roller surface of the contact roller 20a are processed into a tapered shape in which the diameter of the contact roller 20a gradually decreases toward both ends of the contact roller 20a. Then, the end roller surfaces 50b and 50c are pressed against the roller surface 21a of the No. 2 roller 21, and the second pressing parts 61 are formed on both end sides of the first pressing part 60. In this embodiment, part of the polycarbonate resins 28b and 28c is pressed against the end roller surface 50b of the contact roller 20a in the second pressing part 61 with a pressing force lower than that of the first pressing part 60 , 50c and the roller surface 21a of the No. 2 roller 21. Therefore, the thickness of the polycarbonate resins 28b and 28c of the second pressing part 61 is formed to be thicker than the thickness of the acrylic resin 28a and the polycarbonate resin 28b pressed by the first pressing part 60. For example, relative to the film S formed by the first pressing part 60 The thickness of the film S is formed to be approximately 50 μm in the second pressing portion 61 . Furthermore, the end roller surfaces 50b and 50c and the roller surface 21a facing the end roller surfaces 50b and 50c are examples of the second pressing area of the present disclosure.

Figure 3 shows an enlarged view of the central roller surface 50a and the end roller surface 50c of the contact roller 20a. The convex processed central roller surface 50a is at the end of the central roller surface 50a, and the slope of the tangent line has an angle θ1. Furthermore, the slope of the tapered end roller surface 50c has an angle θ2. Furthermore, in the pressing device 12, the angle θ2 and the angle θ1 are processed so that they are substantially equal. In this way, by processing so that θ1≒θ2 can be made similar to the cross-sectional shape of the previous touch roller that has been convexly processed, the pressing force in the width direction of the touch roller 20a can be made uniform.

The molten thermoplastic resin 28 pressed by the contact roller 20a and the No. 2 roller 21 is then cooled by passing through the cooling portion 62 formed by the roller surface 21a of the No. 2 roller 21 and the roller surface 22a of the No. 3 roller 22. Here, in order to cool the molten thermoplastic resin 28, the molten thermoplastic resin 28 may be brought into contact with the roller surface 21a of the No. 2 roller 21 and the roller surface 22a of the No. 3 roller 22, or it may only pass through the roller surface. 21a and roller surface 22a. Furthermore, it is preferable that the roller surface 21a of the No. 2 roller 21 and the roller surface 22a of the No. 3 roller 22 are both cylindrical surfaces.

The molten thermoplastic resin 28 cooled by the roll surface 21a of the No. 2 roll 21 and the roll surface 22a of the No. 3 roll 22 is discharged as the film S from the No. 3 roll 22. As shown in FIG. 3 , the film S is formed with an area Sa pressed by the first pressing part 60 with a high pressing force, and areas Sb and Sc pressed by the second pressing part 61 with a low pressing force. In the case of this embodiment, the region Sa is formed of acrylic resin 28a and polycarbonate resins 28b and 28c, and the regions Sb and Sc are formed of polycarbonate resins 28b and 28c. form. Then, the film S is guided by the aforementioned conveyance roller 23 (see FIG. 2 ) and sent into the inlet 1 a of the biaxial synchronous stretching device 14 .

The areas at both ends of the film S fed into the biaxial synchronous stretching device 14 in the width direction (X-axis direction) formed of the polycarbonate resins 28b and 28c are held by the clips 30 (see FIG. 1) in the moving direction (Y-direction). and extend in the width direction.

Furthermore, the contact roller 20a is preferably a metal rigid roller from the viewpoint of surface smoothness and thickness uniformity. Then, a high-hardness film is formed on the central roller surface 50a and the end roller surfaces 50b and 50c by HCr (hard chromium plating) processing. In addition, the contact roller 20a may be an elastic roller such as a metal elastic roller.

3 illustrates an example in which both ends of the roller surface of the contact roller 20a are processed into a tapered shape and the center portion of the roller surface of the contact roller 20a is convexly processed. However, even if the contact roller 20a is shaped It is cylindrical. The No. 2 roller 21 is formed into the same shape as the contact roller 20a in Fig. 3, and the same effect can still be obtained. However, if the No. 2 roller 21 is tapered, the adhesion between the No. 2 roller 21 and the No. 3 roller 22 decreases, so the cooling performance of the molten thermoplastic resin 28 may decrease. Therefore, it is preferable to taper the side of the contact roller 20a. Furthermore, since the No. 2 roller 21 cannot be removed, a roller cleaning device is installed for cleaning. If the No. 2 roller 21 is tapered, the contact of the cleaner when installing the roller cleaning device is weak, and there is a risk of wiping residue or uneven wiping. Therefore, the No. 2 roller 21 preferably has a width of flat.

As described above, in the stretched film manufacturing apparatus 10, the central roller surface 50a (first pressing area) of the touch roller 20a (first roller) and the roller surface 21a (2nd roller) of the No. 2 roller 21 (second roller) 1st pressing area) The first pressing part 60 is formed to press the acrylic resin 28a (first thermoplastic resin) introduced from the T-shaped mold 24 (injection part) with a high pressing force. Furthermore, the second roller surface 50b and 50c (second pressing area) of the contact roller 20a (first roller) and the roller surface 21a (second pressing area) of the No. 2 roller 21 (second roller) are formed. The pressing part 61 presses the polycarbonate resin 28b (second thermoplastic resin) on both ends in the width direction of the acrylic resin 28a introduced from the T-shaped mold 24 (injection part) with a pressing force lower than the first pressing area. Furthermore, the cooling part 62 cools by sandwiching the acrylic resin 28a and the polycarbonate resin 28b with the No. 2 roller 21 (second roller) and the No. 3 roller 22 (third roller). Then, the biaxial synchronous stretching device 14 (extension part) holds the areas of the polycarbonate resin 28b at both ends of the film S formed of the acrylic resin 28a and the polycarbonate resin 28b cooled by the cooling part 62, and stretches the film S on It extends in the direction of movement and the width direction orthogonal to the direction of movement. Therefore, when the film S is stretched, no stress concentration areas are formed, so there is no need to provide a trimming step before stretching. In addition, the end portion of the thermoplastic resin is pressed with a low pressure, thereby suppressing the occurrence of wrinkles, and the polycarbonate resin 28b at the end portion of the film S is stronger than the acrylic resin 28a, so it does not stretch when stretched. Will break. Therefore, a stretched film with high thickness accuracy can be produced. Furthermore, since no trimming step is required, the device can be saved in steps and space, and there is no need to process the film removed in the trimming step. Furthermore, the usage amount of the polycarbonate resin 28b molded at the end portion can be the minimum required, so the yield is improved.

Moreover, in the stretched film manufacturing apparatus 10, the end roller surfaces 50b and 50c (2nd pressing area) of the touch roller 20a (1st roller) are formed so that the diameter of the touch roller 20a may gradually decrease toward both ends. Therefore, the injected molten thermoplastic resin 28 is pressed in the second pressing area with a lower pressing force than in the first pressing area. Thereby, both end portions of the film S can be formed thicker than the central portion.

Moreover, in the stretched film manufacturing apparatus 10, the 1st pressing part 60 of the contact roller 20a (1st roller) is convexly processed. Therefore, in the first pressing portion 60 , the contact roller 20 a can be reliably pressed against the No. 2 roller 21 (second roller).

Moreover, in the stretched film manufacturing apparatus 10, when the touch roller 20a (first roller) is cut by the surface including the roller axis of the touch roller 20a, the end portion of the center roller surface 50a (first pressing area) The slope of the tangent line of the center roller surface 50a is substantially equal to the slope of the end roller surfaces 50b and 50c (second pressing area) of the contact roller 20a. Therefore, the cross-sectional shape of the contact roller 20a can be approximated by the convex surface processing, so that the pressing force in the width direction of the contact roller 20a can be made uniform.

Moreover, in the stretched film manufacturing apparatus 10, the contact roller 20a (1st roller) is a metal rigid roller or an elastic roller. Therefore, the molten thermoplastic resin 28 can be reliably pressed in the first pressing portion 60 .

Moreover, in the stretched film manufacturing apparatus 10, the touch roll 20a (1st roll), the No. 2 roll 21 (2nd roll), and the No. 3 roll 22 (3rd roll) contain a heat medium inside. Therefore, the injected molten thermoplastic resin 28 can be reliably cooled.

Furthermore, in the stretched film manufacturing apparatus 10, the first thermoplastic resin is an acrylic resin, and the second thermoplastic resin is a polycarbonate resin. Therefore, the end portion of the film S can be reinforced without causing wrinkles or thick portions.

[Modification example of the first embodiment]

Next, a modification example of the first embodiment will be described using FIG. 4 . FIG. 4 is a plan view of the pressing part and the cooling part of the stretched film manufacturing apparatus according to the modified example of the first embodiment.

This embodiment is an example in which a touch roller 20b is used instead of the touch roller 20a of the first embodiment. The central roller surface 50d (first pressing area) of the contact roller 20b is not convexly processed and forms a cylindrical surface.

By pressing the contact roller 20b against the No. 2 roller 21, the film S is formed from the injected molten thermoplastic resin 28. At this time, part of the acrylic resin 28a and polycarbonate resin 28b in the center is pressed with a high pressing force, and the polycarbonate resin 28b in both end parts is pressed with a low pressing force. Therefore, like the first embodiment, the polycarbonate resin 28b at both ends is formed to be thicker than the acrylic resin 28a at the center.

(Second Embodiment)

Next, a second embodiment of the present disclosure will be described using FIG. 5 . FIG. 5 is a plan view of the pressing part and the cooling part of the stretched film manufacturing apparatus according to the modified example of the second embodiment.

This embodiment is an example in which a touch roller 20c is used instead of the touch roller 20a of the first embodiment. The touch roller 20c has end roller surfaces 50e and 50f instead of the end roller surfaces 50b and 50c (see FIG. 3 ). The end roller surfaces 50e and 50f form a cylindrical surface with a smaller diameter relative to the convexly processed center roller surface 50a. That is, a step difference is formed between the center roller surface 50a and the end roller surfaces 50e and 50f.

When the contact roller 20c is pressed against the No. 2 roller 21, the center roller surface 50a of the contact roller 20c is pressed against the roller surface 21a of the No. 2 roller 21, thereby forming the first pressing portion 60. In addition, the end roller surface of the contact roller 20c 50b and 50c are pressed against the roller surface 21a of the No. 2 roller 21 to form the second pressing portion 61.

At this time, the first pressing part 60 is pressed with a high pressing force, and the second pressing part 61 is pressed with a low pressing force. Therefore, the portions of the polycarbonate resin 28b (regions Sb, Sc) at both ends of the molten thermoplastic resin 28 are formed thicker than the portions of the acrylic resin 28a and the polycarbonate resin 28b (region Sa) at the center.

[Modification example of the second embodiment]

Next, a modification example of the second embodiment will be described using FIG. 6 . FIG. 6 is a plan view of the pressing part and the cooling part of the stretched film manufacturing apparatus according to the modification of the second embodiment.

This embodiment is an example in which a touch roller 20d is used instead of the touch roller 20c of the second embodiment. The central roller surface 50d (first pressing area) of the contact roller 20d is not convexly processed and forms a cylindrical surface.

The contact roller 20d is pressed against the No. 2 roller 21 to form the film S from the injected molten thermoplastic resin 28. At this time, parts of the acrylic resin 28a and the polycarbonate resin 28b (areas Sa) in the center are pressed with a relatively high pressing force, and parts of the polycarbonate resin 28b (areas Sb and Sc) at both ends are pressed with a relatively high pressing force. Press with low pressing force. Therefore, similarly to the second embodiment, a portion of the polycarbonate resin 28b at both ends is formed thicker than a portion of the acrylic resin 28a and the polycarbonate resin 28b at the center.

As explained above, in the stretched film manufacturing apparatus 10, the end roller surfaces 50e and 50f (the second pressing area) of the touch roller 20c (the first roller) are longer than the center roller surface 50a (the first pressing area) of the contact roller 20c. by A cylindrical surface with a smaller diameter is formed. Therefore, the injected molten thermoplastic resin 28 is pressed in the second pressing area with a lower pressing force than in the first pressing area. Thereby, both end portions of the film S can be formed thicker than the central portion.

12: Pressing device (first pressing part, second pressing part, cooling part)

20b: Contact roller (1st roller)

21:No.2 roller (2nd roller)

21a: Roller surface (first pressing area, second pressing area)

22:No.3 roller (3rd roller)

22a: Roller surface

27a, 27b, 27c: Rotation axis

28: Molten thermoplastic resin

28a: Acrylic resin (first thermoplastic resin)

28b: Polycarbonate resin (second thermoplastic resin)

50b, 50c: End roller surface (second pressing area)

50d: Center roller surface (first pressing area)

60: 1st compression part

61: 2nd compression part

S: membrane

Sa,Sb,Sc: area

X,Y,Z: axis

Claims (8)

A stretch film manufacturing apparatus, which is provided with an input unit that inputs a molten first thermoplastic resin into a central portion in the width direction, and inputs a molten second thermoplastic resin into both end sides of the first thermoplastic resin in the width direction. ; The first pressing part, which presses the first thermoplastic resin and the second thermoplastic resin introduced from the aforementioned input part in the first pressing area of the first roller and the second roller; and the second pressing part, which In the second pressing areas at both ends of the first pressing area of the first roller and the second roller, the second thermoplastic resin is injected from the input part with a pressing force lower than that of the first pressing area. Pressing; a cooling unit that, after pressing the first thermoplastic resin and the second thermoplastic resin by the first roller and the second roller, passes through and is arranged on the second roller through the second roller. between the third roller on the opposite side of the first roller to be cooled; and an extension portion that holds the two ends of the film formed of the first thermoplastic resin and the second thermoplastic resin that have been cooled by the cooling portion. The area of thermoplastic resin extends the film in the moving direction and the width direction orthogonal to the moving direction. The stretched film manufacturing apparatus of Claim 1, wherein the first roller and the second pressing area are formed in such a manner that the diameter of the first roller gradually decreases toward both ends. The stretched film manufacturing apparatus of claim 1, wherein the second pressing area before the first roller is formed with a cylindrical surface having a smaller diameter than the first pressing area before the first roller. The stretch film manufacturing apparatus according to claim 2 or 3, wherein the first pressing area of the first roller is convexly processed. The stretch film manufacturing apparatus of Claim 2, wherein when the first roller is cut with a surface including the roller axis of the first roller, the tangent line of the first pressing area at an end of the first pressing area is The slope is substantially equal to the slope of the second pressing area before the first roller. The stretch film manufacturing device according to any one of claims 1 to 3, wherein the first roller is a metal rigid roller or an elastic roller. The stretched film manufacturing apparatus according to any one of claims 1 to 3, wherein the first roller, the second roller, and the third roller contain a heat medium inside. The stretched film manufacturing apparatus according to any one of claims 1 to 3, wherein the first thermoplastic resin is an acrylic resin, and the second thermoplastic resin is a polycarbonate resin.