JP2020146896A - T-die cleaning device and t-die cleaning method - Google Patents

Abstract

To provide a T-die cleaning device and a T-die cleaning method capable of removing an adherent resin adhering and remaining on a T-die without stopping a production line, and improving productivity, reducing the amount of a wasted resin material, and reducing work load.SOLUTION: A T-die cleaning device 20 and a cleaning method for removing an adherent resin adhering and remaining on a T-die 10 having a discharge opening 11 extending in one direction in a horizontal plane are provided, in which a scraper 50 is brought, in a pressed state, into contact with one of the opening edges of the discharge opening 11 located on the upstream side with respect to the direction of rotation of a cooling roll 15, and the scraper 50 is reciprocally slid along the discharge opening 11 in the one direction by a sliding drive mechanism 21 without stopping the extrusion of a molten resin material.SELECTED DRAWING: Figure 2

Description

The present invention relates to a T-die cleaning device for removing the adhering resin remaining on the T-die in the process of molding the sheet-shaped resin molded body, and a method for cleaning the T-die.

For example, a casting method is known as a method for producing a sheet-shaped resin molded product such as a plastic sheet. In this method, a molten resin material is extruded into a sheet from the T-die discharge port onto the surface of a cooling roll by an extruder equipped with a T-die having a discharge port (lip) extending linearly in one direction. A sheet-shaped resin molded body is continuously molded by quenching and rolling with a cooling roll.

In extrusion molding, if the molding operation is continued for a long time, the resin material adheres to the opening edge of the discharge port of the T-die, and the adhered resin material discolors due to thermal deterioration with the passage of time. It is known that it remains as a foreign substance called "mayani".
If molding is continued with the mold attached to the discharge port of the T-die, the mold may be mixed into the molded product and its quality may be deteriorated, or traces of the mold (die line) may be formed in a streak on the surface of the molded product. There is a problem that the appearance is spoiled.
Therefore, in extrusion molding, it is necessary to carry out the work of removing the meshi remaining on the T-die at a predetermined frequency.

Various techniques have been proposed so far as countermeasures against eyebrows that inevitably occur in extrusion molding. For example, Patent Document 1 proposes a method of wiping off the adhering resin remaining in the discharge port of the T-die by pressing and sliding a resin wipe having a recess applied to the discharge port of the T-die.

Japanese Unexamined Patent Publication No. 2017-159591

Therefore, in the method described in Patent Document 1, it is necessary to stop the molding work and temporarily stop the production line when performing the eyelid removal work, and the eyebrows work itself requires a long time. , There is a problem of reducing productivity. Moreover, the resin material may be extruded while the resin material is removed, and there is a problem that the resin material discharged during the eyelid removal work is wasted.

In the extrusion molding machine using the casting method, the present inventors have only one opening edge where the resin material is attached to the discharge port of the T-die on the upstream side in the cooling roll rotation direction of the discharge port. It was found that the scraper can be slid back and forth to perform the meshi removal work without stopping the production line, and the present invention has been completed.
That is, according to the present invention, the resin material adhering to and remaining on the T-die can be removed without stopping the production line, and therefore high productivity can be obtained and the amount of wasted resin material can be as much as possible. It is an object of the present invention to provide a T-dice cleaning device and a T-dice cleaning method capable of reducing the work load.

The T-die cleaning device of the present invention has a discharge port extending in one direction in a horizontal plane, extrudes a molten resin material into a sheet shape, and cleans for removing the adhering resin adhering to the T-die that is discharged to the surface of a cooling roll. A device in which the tip is pressed against one opening edge of the discharge port located upstream of the rotation direction of the cooling roll that is rotationally driven around a rotation axis extending in one direction. The above-mentioned problems are solved by having a structure provided with a scraper to be abutted and a sliding drive mechanism for sliding the scraper back and forth in the one direction along the discharge port.

The T-die cleaning method of the present invention has a discharge port extending in one direction in a horizontal plane, extrudes a molten resin material into a sheet shape, and removes the adhering resin adhering to the T-die discharged on the surface of a cooling roll. In the method, the extrusion of the molten resin material is stopped in a state where the scraper is brought into contact with one opening edge of the discharge port located upstream in the rotation direction of the cooling roll in a pressed state. The above problem is solved by sliding the scraper back and forth in the one direction along the discharge port without doing so.

According to the T-dice cleaning device according to claim 1 and the T-dice cleaning method according to claim 8, the adhered resin remaining on the T-dice can be removed without stopping the production line, resulting in high production. You can get sex. Furthermore, by cleaning the T-die before the resin adhering to the T-die deteriorates over time or while the amount of adhering is small, the resin scraped off by the scraper is dropped onto the surface of the cooling roll. Even in this case, the quality of the obtained molded product is not deteriorated, and the wasted resin material can be reduced as much as possible. Moreover, since it is not necessary for the operator (operator) to perform the cleaning work of the T-die, the work load can be significantly reduced.

According to the T-die cleaning device according to claim 2 and the T-die cleaning method according to claim 9, the scraper's contact position with respect to the T-die can be controlled only by moving the scraper in one direction. Therefore, the position of the scraper can be easily controlled.
Further, since the pressing force of the scraper against the T die can be adjusted to an appropriate size, the adhesive resin remaining attached to the T die can be reliably removed.

According to the T-die cleaning device according to claim 3 and the T-die cleaning method according to claim 10, after the T-die removed during maintenance is reattached to the extruder, the scraper is suitable for the T-die. The contact state can be obtained with high reproducibility, and it is possible to reliably avoid molding defects such as resin breakage (phenomenon such as tearing and perforation) caused by the scraper coming into contact with the resin material. .. Further, since the scraper can be uniformly brought into contact with the T die in one direction in which the discharge port of the T die extends, the adhesive resin remaining attached to the T die can be removed more reliably.

According to the T-die cleaning device according to claim 4 and the T-die cleaning method according to claim 11, it is possible to prevent the resin from adhering to and accumulating on the scraper itself, thereby achieving the desired cleaning effect. You can definitely get it.

According to the T-die cleaning device according to claim 5 and the T-die cleaning method according to claim 12, it is possible to prevent the scraper from rusting and obtain the desired function for a long period of time. Can be done.

According to the T-die cleaning device according to claim 6 and the T-die cleaning method according to claim 13, the contact area of the scraper with respect to the molten resin material extruded from the T-die can be reduced as much as possible. Therefore, it is possible to reliably avoid the occurrence of molding defects.

According to the T-die cleaning device according to claim 7, since the cleaning device is in a state where it does not come into direct thermal contact with the T-die, a high heat insulating effect can be obtained and the temperature drop of the T-die is suppressed. be able to. In addition, the rigidity of the extrusion molding machine can be improved.

It is a figure which shows typically an example of the extrusion molding line by the T die method. It is a figure which shows roughly the structure around the T die in the extrusion molding line shown in FIG. It is a perspective view seen from the front side which shows the structure in the example of the T die cleaning device which concerns on this invention. It is a figure which shows the structure in one example of a scraper, is (a) side view, (b) perspective view seen from the upper surface side, (c) top view. It is a figure which shows the structure of the scraper moving mechanism schematicly. It is a figure which shows roughly the structure of the position adjustment mechanism.

Hereinafter, embodiments of the present invention will be described with reference to the drawings, taking as an example a case where a T-die cleaning device is applied to an extrusion molding line for molding a single-layer sheet or film of a thermoplastic resin.
FIG. 1 is a diagram schematically showing an example of an extrusion molding line by the T-die method, and FIG. 2 is a diagram schematically showing a configuration of a main part in the extrusion molding line shown in FIG.
This extrusion molding line is formed so that a slit-shaped discharge port (lip) 11 opening on the lower surface extends in one direction (in the directions perpendicular to the paper surface in FIGS. 1 and 2) in a horizontal plane, and is formed of a molten resin material. A plurality of T-dies 10 extruded into a shape, and a plurality of cooling rolls 15 for forming a resin sheet S by rapidly cooling the molten resin material that is rotationally driven around the rotation shaft C extending in one direction and discharged from the T-dies 10. A resin sheet conveying means 16 including a conveying roll 17 and a take-up roll 18 for collecting the resin sheet S are provided. In the following, for convenience, the one direction is the "X direction", the direction orthogonal to the X direction in the horizontal plane (horizontal direction in FIGS. 1 and 2) is the "Y direction", and the vertical direction (up and down in FIGS. 1 and 2). Direction) is defined as "Z direction".

In this extrusion molding line, the T-die cleaning device 20 for removing the adhering resin adhering to and remaining on the opening edge of the discharge port 11 of the T-die 10 is arranged in the rotation direction of the cooling roll 15 along the outer peripheral surface of the cooling roll 15. On the other hand, it is arranged at a position on the upstream side of the T die 10. The T-dice cleaning device 20 is attached to a support frame (not shown) that suspends and supports the T-dice 10, so that the T-dice cleaning device 20 does not come into direct thermal contact with the T-dice 10.

The T-die cleaning device 20 discharges a scraper 50 and a scraper 50 whose tip is pressed against one opening edge of a discharge port 11 located upstream of the rotation direction of the cooling roll 15. A sliding drive mechanism 21 that slides back and forth in the X direction along the outlet 11 is provided. The sliding drive mechanism 21 is not particularly limited, but can be configured by, for example, a ball screw mechanism.

FIG. 3 is a perspective view showing the configuration of an example of the T-die cleaning device according to the present invention as viewed from the front side.
The T-dice cleaning device 20 includes a square tubular horizontal rod portion 26 extending horizontally in the X direction and a square tubular pillar portion 27 extending in the Z direction continuously at both ends of the horizontal rod portion 26, respectively. A main frame 25 having a flat plate-shaped pedestal portion 28 fixed to the lower end of the support column portion 27 of the above is provided.

A holding member 30 for holding two rod-shaped lower linear guides 37, 37 is fixed to the lower surface of the pedestal portion 28 of the main frame 25.
The holding member 30 includes a block-shaped upper surface side holding member 31 and a block-shaped lower surface side holding member 33 that are screwed and fixed to each other, and both ends of each of the two lower linear guides 37 and 37 are X. It is configured to be sandwiched and held in a posture extending horizontally in the X direction while projecting outward in the direction. In the present embodiment, the two lower linear guides 37, 37 are held so as to be aligned in the Y direction at the same level position in the Z direction.
The upper surface side holding member 31 is formed with a screw shaft insertion hole 32 into which the screw shaft 22 constituting the ball screw mechanism is inserted at a level position on the upper side in the Z direction with respect to the lower linear guides 37 and 37.

The screw shaft 22 is held in a posture extending horizontally in the X direction by the following holding structure. That is, at the outer positions of both ends of the main frame 25 in the X direction, a pair of side plates 40, 40 constituting a mounting portion for the support frame supporting the T die 10 are arranged so as to face each other, and the screw shaft 22 Both ends are rotatably held by movable plates 71 constituting the position adjusting mechanism 70 described later, which are provided on the outer surfaces of the side plates 40 and 40, respectively. A drive motor 23 that rotationally drives the screw shaft 22 so as to be able to rotate in the forward and reverse directions is connected to one end of the screw shaft 22.

In the T-die cleaning device 20, a block-shaped head portion 45 that is slid back and forth in the X direction by the rotation of the screw shaft 22 is slidably attached to the lower linear guide 37. The head portion 45 is formed with a screw shaft insertion hole 46, and the screw shaft insertion hole 46 is provided with a nut member 24 that is screwed and mounted on the screw shaft 22. A connecting plate 47 extending upward in the Z direction is fixed to the back surface of the head portion 45, and a guide block 48 slidably attached to the upper linear guide 35 is fixed to the upper end portion of the connecting plate 47. Has been done. The upper linear guide 35 is fixed in a posture extending horizontally in the X direction with respect to the fixed rail member 36 provided on the back surface of the horizontal rod portion 26 of the main frame 25.
A flat plate-shaped bracket 49 extending in the front direction is provided on the lower surface of the head portion 45, and a scraper 50 is fixed to the tip of the bracket 49 by, for example, screwing.

As shown in FIG. 4, the scraper 50 has a fixed end portion 51 that is abutted against and fixed to the lower surface of the bracket 49, and a flexible arm that is continuous with the fixed end portion 51 and extends downward in the front direction. It has a portion 52 and a tip portion 53 continuous with the flexible arm portion 52.
The tip portion 53 has a flat T-dice contact surface 54 on the upper surface, and has a form such that the contact area with the molten resin material extruded from the T-dice is as small as possible. Specifically, the tip portion 53 is formed with both side surfaces tapered so that the width dimension (X direction dimension) decreases toward the tip, and the thickness (Z direction dimension) decreases toward the tip. The lower surface is an inclined surface that extends upward in the front direction.

The material constituting the scraper 50 is not particularly limited as long as it is rigid and has a hardness smaller than that of the constituent material of the T-die (for example, a casting), but rusting due to the adhesion of the resin may occur. For example, an aluminum material is preferably used because it can be avoided. Here, the aluminum material includes pure aluminum and an aluminum alloy.
Further, it is more preferable that the surface of the scraper 50 is coated with a slippery material in order to prevent the resin from adhering to the scraper 50 itself.
As the coating material, for example, it is preferable to use a fluorine-based resin such as polytetrafluoroethylene (PTFE).

As shown in FIG. 5, the T-dice cleaning device 20 is located between an operating position L1 in which the scraper 50 is in contact with the T-dice 10 and a retracting position L2 separated from the T-dice 10 on the cooling roll 15 side. It is provided with a scraper moving mechanism 60 that moves in the Z direction.
The scraper moving mechanism 60 is composed of, for example, an air cylinder 61. The bracket 49 is fixed to the tip of the piston rod 62 extending in the Z direction, and is urged upward in the Z direction by an elastic member (not shown). Therefore, when the scraper 50 is in the operating position L1, as shown in FIG. 2, the tip of the scraper 50 is located on the upstream side in the rotation direction of the cooling roll 15 at the discharge port 11 of the T die 10. Is abutted in a pressed state.
In FIGS. 3 and 5, reference numeral 65 denotes a cable carrier for holding an operating air supply / discharge hose (not shown) to the air cylinder 61, one end of which is horizontal in the X direction at a position above the head portion 45. It is fixed to a support rail 66 arranged so as to extend, and the other end is fixed to a support 67 provided on the upper surface of the head portion 45.
The retracted position L2 of the scraper 50 can be set at a position where the separation distance h between the T-dice contact surface 54 and the lower surface of the T-die 10 at the tip portion 53 of the scraper 50 is within the range of 0 to 20 mm.

Further, in the T-die cleaning device 20, a position adjusting mechanism 70 for adjusting the relative inclinations of the screw shaft 22, the upper linear guide 35, and the lower linear guide 37 in the Y direction and the Z direction with respect to the discharge port 11 is provided. It is provided on the outer surface side of the side plates 40, 40 in the X direction.

As shown in FIG. 6, the position adjusting mechanism 70 includes a rectangular movable plate 71, an upper surface side fixing plate 72 provided above the movable plate 71 at a position separated from the movable plate 71, and a front surface of the movable plate 71. A front side fixing plate 73 provided at a side position separated from the movable plate, and a plurality of adjusting screws 74 for adjusting the positions of the movable plate 71 with respect to the upper surface side fixing plate 72 and the front side fixing plate 73 are provided. ing.
The upper surface side fixing plate 72 is fixed by being screwed to the outer surface of the side plate 40 so as to extend in the horizontal direction.
The front side fixing plate 73 is screwed and fixed to the outer surface of the side plate 40 so as to extend in the vertical direction.
The movable plate 71 is connected to each of the upper surface side fixing plate 72 and the front side fixing plate 73 by a plurality of adjusting screws 74 via a gap, and is connected to the outer surface of the side plate 40 via a plate-shaped washer 75. It is screwed and provided so that it can be displaced minutely. As described above, the movable plate 71 rotatably holds the screw shaft 22 and holds the end portion of the lower linear guide 37.

An exterior body 80 covering the lower surface, the back surface, and both side surfaces is attached to the T-dice cleaning device 20 by being screwed to the movable plate 71 of the position adjusting mechanism 70.
On the back surface of the exterior body 80, for example, three oil smoke exhaust fans 81 are installed at positions arranged in the X direction.

Hereinafter, the resin material removal treatment by the T-die cleaning device 20 of the above embodiment will be described.
First, the scraper 50 at the retracted position L2 is moved upward in the Z direction so as to be positioned at the operating position L1 by the scraper moving mechanism 60, and the T-die contact surface 54 at the tip portion 53 of the scraper 50 ejects the T-die 10. The cooling roll 15 at the outlet 11 is brought into contact with one of the opening edges located upstream in the rotation direction in a pressed state. At this time, if the T-die 10 once removed for maintenance or the like is reattached, the position adjusting mechanism 70 causes the screw shaft 22, the upper linear guide 35, and the lower linear guide 37 to be discharged from the outlet 11. The relative tilts in the Y and Z directions with respect to are adjusted.

As described above, in the extrusion molding line, the resin inevitably remains attached to the opening edge of the discharge port 11 of the T-die 10 in the process of performing the molding operation, but the adhered resin is heat. Before the deterioration, the adhering resin removing treatment by the T-die cleaning device 20 is performed without stopping the extrusion molding line, in other words, without stopping the extrusion of the molten resin material.
The adhering resin removing treatment is carried out, for example, when a predetermined amount of the molten resin material is extruded from the discharge port 11 of the T die 10, or when a predetermined time has elapsed since the previous adhering resin removing treatment was performed. However, it may be continuously carried out during the molding operation.
In the adhering resin removing process, the screw shaft 22 is rotated in the forward and reverse directions by the drive motor 23, so that the head portion 45 reciprocates in the X direction while being guided by the upper linear guide 35 and the lower linear guide 37. Be moved. As a result, the tip 53 of the scraper 50 is reciprocally slid in the X direction along the opening edge of the discharge port 11 of the T die 10, and the adhesive resin inevitably adheres and remains on the opening edge of the discharge port 11 of the T die 10. Is scraped off. The scraped resin is dropped and mixed into the resin material film before curing on the surface of the cooling roll 15.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made.
For example, the T-die cleaning device according to the present invention is not only an extrusion molding line for molding a single-layer sheet or film of a thermoplastic resin (plastic), but also a multi-layer sheet product or film product in which a plurality of different materials are laminated. Alternatively, it can also be used to remove the adhering resin remaining adhering to the discharge port of the T-die used in the extrusion molding line for molding the laminated product.

10 ・ ・ ・ T-dice 11 ・ ・ ・ Discharge port (lip)
15 ・ ・ ・ Cooling roll 16 ・ ・ ・ Resin sheet transporting means 17 ・ ・ ・ Transport roll 18 ・ ・ ・ Winding roll 20 ・ ・ ・ T-die cleaning device 21 ・ ・ ・ Sliding drive mechanism 22 ・ ・ ・ Screw shaft 23・ ・ ・ Drive motor 24 ・ ・ ・ Nut member 25 ・ ・ ・ Main frame 26 ・ ・ ・ Horizontal rod part 27 ・ ・ ・ Strut part 28 ・ ・ ・ Pedestal part 30 ・ ・ ・ Holding member 31 ・ ・ ・ Top surface side holding member 32 ・ ・ ・ Screw shaft insertion hole 33 ・ ・ ・ Lower surface side holding member 35 ・ ・ ・ Upper linear guide 36 ・ ・ ・ Fixed rail member 37 ・ ・ ・ Lower linear guide 40 ・ ・ ・ Side plate 45 ・ ・ ・ Head part 46 ・・ ・ Screw shaft insertion hole 47 ・ ・ ・ Connecting plate 48 ・ ・ ・ Guide block 49 ・ ・ ・ Bracket 50 ・ ・ ・ Scraper 51 ・ ・ ・ Fixed end 52 ・ ・ ・ Flexible arm 53 ・ ・ ・ Tip 54・ ・ ・ T-die contact surface 60 ・ ・ ・ Scraper movement mechanism 61 ・ ・ ・ Air cylinder 62 ・ ・ ・ Piston rod 65 ・ ・ ・ Cable carrier 66 ・ ・ ・ Support rail 67 ・ ・ ・ Support 70 ・ ・ ・ Position Adjustment mechanism 71 ・ ・ ・ Movable plate 72 ・ ・ ・ Top side fixing plate 73 ・ ・ ・ Front side fixing plate 74 ・ ・ ・ Adjustment screw 75 ・ ・ ・ Washer 80 ・ ・ ・ Exterior body 81 ・ ・ ・ Oil smoke exhaust fan C・ ・ ・ Rotating shaft S ・ ・ ・ Resin sheet

Claims (13)

A cleaning device that has a discharge port that extends in one direction in a horizontal plane and extrudes a molten resin material into a sheet to remove the residual resin that adheres to the T-die that is discharged to the surface of the cooling roll.
A scraper whose tip is pressed against one opening edge of the discharge port located upstream of the rotation direction of the cooling roll driven to rotate about a rotation axis extending in one direction. A T-die cleaning device comprising a sliding drive mechanism for sliding the scraper back and forth in the one direction along the discharge port. The claim is characterized by comprising a scraper moving mechanism for moving the scraper in the vertical direction between an operating position where the scraper is in contact with the T die and a retracting position separated from the T die on the cooling roll side. The T-dice cleaning device according to 1. The sliding drive mechanism is composed of a ball screw mechanism having a screw shaft extending horizontally in one direction.
The first or second aspect of the present invention further comprises a position adjusting mechanism for adjusting the inclination of the screw shaft in the horizontal plane with respect to the discharge port of the T-die in the direction orthogonal to the one direction and the vertical direction. The T-die cleaning device described. The T-die cleaning device according to any one of claims 1 to 3, wherein the surface of the scraper is coated with a slippery material. The T-die cleaning device according to claim 4, wherein the scraper is made of an aluminum material. The T according to any one of claims 1 to 5, wherein the tip portion of the scraper is configured such that the width dimension decreases toward the tip and the thickness decreases toward the tip. Dice cleaning device. The T-dice cleaning device according to any one of claims 1 to 6, further comprising a mounting portion for a support member that supports the T-dice. A cleaning method that has a discharge port that extends in one direction in a horizontal plane, extrudes a molten resin material into a sheet, and removes the residual resin that adheres to the T-die that is discharged to the surface of the cooling roll.
In a state where the scraper is in contact with one opening edge of the discharge port located on the upstream side in the rotation direction of the cooling roll in a pressed state, the extruding of the molten resin material is not stopped. A method for cleaning a T-die, which comprises sliding the scraper back and forth in the one direction along the discharge port. The T-die according to claim 8, wherein when the scraper is brought into contact with the T-die, the scraper is moved in the vertical direction from a retracted position separated from the T-die on the cooling roll side. Cleaning method. The scraper is slid back and forth by a ball screw mechanism provided with a screw shaft extending in one direction.
The method for cleaning a T-die according to claim 8 or 9, wherein the position adjustment for adjusting the inclination of the screw shaft in the horizontal plane with respect to the discharge port in the direction orthogonal to the one direction and the vertical direction is performed. .. The method for cleaning a T-die according to any one of claims 8 to 10, wherein a scraper whose surface is coated with a material having a slipperiness to the T-die is used. The method for cleaning a T-die according to claim 11, wherein a scraper made of an aluminum material is used as the scraper. The T-die according to any one of claims 8 to 12, wherein the scraper is configured so that the width dimension decreases toward the tip and the thickness decreases toward the tip. How to clean.

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