JP2002248670A - Method for manufacturing sheet and mouthpiece for extrusion molding sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a sheet capable of simply and effectively regulating its thickness so as to manufacture the sheet and a mouthpiece for extrusion molding the sheet. SOLUTION: The mouthpiece for manufacturing the sheet enables the accurate regulation of the thickness by utilizing a thermal expansion of a bolt, then the regulation of the thickness of the end of the sheet from a neutral point of a lip deformation. Thus, the mouthpiece is free from a problem steps such as a disengagement of a clip or the like in the manufacturing process of the sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet manufacturing method and a sheet extrusion die.

[0002]

2. Description of the Related Art Conventionally, sheets such as polyester, polypropylene, polyamide, and polycarbonate films are generally manufactured by the steps shown in FIG.

In FIG. 4, a molten material is extruded from an extruder 1, a discharge amount is made constant by a gear pump 2, foreign matters are removed through a filter 3, and a direction perpendicular to a direction in which a sheet is discharged from a mouthpiece 4. The sheet is formed by widening in the die width direction (a direction perpendicular to the paper surface; hereinafter, sometimes simply referred to as the width direction) and discharging to form a sheet. After the process, it is wound by the winder 7. FIG. 4 illustrates one process as a stretching device. A stretching method such as a sequential biaxial stretching including a longitudinal stretching process for stretching in the sheet conveying direction, and a transverse stretching process for stretching in the sheet width direction. Is also commonly used. The thickness profile of the sheet in the width direction is measured by the thickness gauge 8, and in order to manufacture a product-level sheet, the difference between the current thickness profile measurement value and the target value is calculated by the thickness controller 9 to become the target value. Feedback to the base 4.

FIG. 5 shows a general structure of a base. The mouthpiece is usually composed of a manifold section 11 for widening the molten material flowing through the filter in the width direction, and a pair of lips 1 forming a narrow slit 12 between the manifold section 11 for discharging the sheet as a sheet.
3 and a side plate 14. The thickness profile in the width direction of the sheet can be arbitrarily determined by manipulating the slit shape and the temperature of the leading end portion, and thus it is often used for adjusting the thickness of the sheet. The shape of the slit can be adjusted by pushing and pulling a plurality of adjusting bolts 15 arranged along the width direction of the base on the lip at the tip (hereinafter referred to as a manual method), or a cartridge type heater 16 can be installed inside the sleeve or sleeve. A method of heating a bolt by externally mounting a heater of the type and expanding and contracting the bolt by thermal expansion of the bolt to deform a gap shape (hereinafter referred to as a thermal expansion method) is often used. Depending on how the slit shape is determined, the thickness unevenness of the sheet can be controlled to within 1%. The heating of the base body is generally performed by inserting a plurality of cartridge heaters 17 in the width direction of the base and heating the base body, though not shown, by covering the outer peripheral surface of the base with a cast heater.

[0005] Normally, when adjusting the thickness profile of a sheet during sheet production, both manual and thermal expansion methods operate the bolt provided on the lip to widen or narrow the gap of the slit, and adjust the position. Adjust the thickness of the sheet in.

The following terms are defined for the convenience of the following description.

"Push the lip": Push in the screw of the bolt provided at the tip of the lip in the case of the manual type, or expand the bolt in the case of the thermal expansion type to deform the lip in the direction to narrow the slit gap. And reduce the thickness of the sheet.

"Pull the lip": The screw of the bolt provided at the tip of the lip is pulled in in the case of the manual type, and the expansion of the bolt is stopped in the case of the thermal expansion type. To increase the thickness of the sheet.

"Neutral point of lip deformation": The neutral point of pushing and pulling of the lip, in which the lip has no residual stress or distortion.

In order to adjust the thickness of the sheet, the lip must be pushed and pulled with an accuracy of several μm, and a high level of adjusting ability is required. As described above, in the case of the thermal expansion type, the bolt attached to the tip of the lip is expanded by heat and the thickness is adjusted by pushing and pulling the lip. This method is widely and generally used in the manufacture of sheets as the simplest and most accurate method for adjusting the thickness. Similarly, it is common practice to manually adjust the thickness.However, in the case of manual operation, there is a backlash of the screw. Requires skills. In recent years, since the demand for the thickness accuracy of sheet products has become extremely high, it is substantially difficult to adjust the thickness by a manual method. Therefore, it is most preferable to adjust the thickness of the sheet by a thermal expansion method. In the thermal expansion type, in order to make effective use of the thermal expansion of the bolt, there is no play in mounting.

To adjust the thickness of the sheet by the thermal expansion method,
The following steps need to be taken. That is, in order to adjust the thickness of the sheet, an operation of pushing and pulling the lip is required. Therefore, in order to realize this in a thermal expansion system, the lip is pressed in advance by thermally expanding the bolt. Therefore,
The lip can be pulled by the amount that the lip is pressed. The lip push / pull stroke achieved in this manner is in the range where the bolt expands from room temperature to the highest heating temperature. Normally, the pressure is pre-pressed to a point between the room temperature and the maximum heating temperature.

Conventionally, in the manufacture of a sheet, the thickness adjustment of the sheet product portion has been sufficiently possible by the above-described adjustment method.
However, it was difficult to adjust the thickness of the sheet at the end in the width direction only by the thermal expansion method. For example, when the sheet is sequentially biaxially stretched, the sheet is prevented from meandering in the longitudinal stretching step,
In order to form a grip portion with a clip in the transverse stretching step, it is necessary to form the sheet end portion thicker than the sheet center portion. However, in the thermal expansion type, the lip cannot be pulled more than the neutral point of the lip deformation. The range of the adjustable thickness could not be sufficiently taken. That is, since the deformation of the lip cannot be made thicker than the thickness of the sheet edge when the lip is at the neutral point, if the thickness of the sheet edge is adjusted only by the thermal expansion method, there is a problem of meandering and slipping of the clip. Was. Therefore, in practice, the thickness adjustment at the sheet end has to rely on manual adjustment. However, as described above, it is difficult to perform high-precision thickness adjustment by manual adjustment, and as a result, a problem such as clip detachment may occur.

As an example of pushing and pulling a lip from a neutral point, Japanese Utility Model Laid-Open No. 1-89118 discloses the following structure. That is, a piezoelectric element is attached to a bolt attached to a lip without generating residual stress, distortion, or the like by assembling the lip in a direction in which the lip is pushed and in a direction in which the lip is pulled, thereby realizing push and pull of the lip. However, the above publication does not show how to adjust the thickness of the sheet in the width direction end. Further, the piezoelectric element has insufficient heat resistance, and often malfunctions at about 150 ° C. Therefore, a cooling device is indispensable for use in a die for extruding a molten material having a high temperature of about 300 ° C. When the cooling device is provided in a sheet product part, the device becomes large-scale and the thickness is adjusted at a fine pitch in the width direction. Problems such as not being able to do
At present it is difficult to make it practical.

As described above, the thickness adjustment of the central portion of the sheet is easy and easy to use with the conventional thermal expansion type thickness adjusting means, but it is difficult to operate the sheet in the direction of pulling from the neutral point of the lip deformation at the end. Instead, they had to resort to manual adjustments in the manufacture of the sheets.

[0015]

SUMMARY OF THE INVENTION An object of the present invention is to provide a manufacturing method and a die for extrusion molding in which the thickness of a sheet is easily and effectively adjusted in manufacturing the sheet. In particular, it is an object of the present invention to provide a sheet manufacturing method and a die for extrusion molding that realize a sufficient thickness adjustment range even when adjusting the thickness of a sheet end portion and have no process problems such as clip detachment.

[0016]

Means for Solving the Problems The present inventors have made intensive studies to solve the above problems, and as a result, have reached the present invention described below. The sheet manufacturing method and the sheet extrusion die of the present invention have the following configurations.

That is, when a molten material is discharged from a slit formed at a tip of a die to form a sheet, the tip of the die is deformed to adjust the thickness of the sheet. Deformation of the tip of the base at both ends of the base can be deformed so as to expand or contract from the gap when the gap of the slit is at the neutral point of the deformation of the base of the base. It is characterized in that it is carried out by means for deforming the tip of the base using a member.

Also, a first lip whose tip is deformable, a second lip paired with the first lip, and a tip of the first and second lips form a slit. A fixing member for fixing the first and second lips, and a tip of the lip at least at both ends in the width direction of the first lip, so that a gap between the slits is expanded from a neutral point of deformation. A first lip tip deforming means utilizing an inflatable member which can be deformed so as to be reduced.

Furthermore, the tip of the lip at the widthwise end of the second lip can be deformed from the neutral point of deformation so that the gap between the slits increases or decreases. A second lip tip deforming means using a member may be provided.

The first lip tip deforming means includes a first inflatable member having an inflatable property in a direction in which a gap between the slits is reduced, and a gap between the slit and the first lip. Second expandable in the direction in which
And an inflatable member.

Further, the present invention is characterized in that the expandable member expands due to thermal expansion of the member.

Also, a first lip whose tip is deformable, a second lip paired with the first lip, and a tip of the first and second lips form a slit. A fixing member for fixing the first and second lips, and a lip tip deforming means for deforming the tip of the first lip so as to change the gap between the slits. A push / pull block located on the opposite side of the slit of the first lip tip, a base portion of the first lip provided between the tip and the push / pull block, The structure may include a first inflatable member coupled to the tip of the first lip and the push / pull block, respectively, and a second inflatable member coupled to the base portion and the push / pull block, respectively. Can.

Further, the first and second expandable members at the tip of the first lip are expanded by thermal expansion of the member.

The lip tip deforming means may be provided with a cooling means for cooling the lip tip deforming means.
It can be provided at the end in the base width direction.

Further, the push-pull block is made of a heat-insulating material.

Here, the expandable member refers to a member which expands in a single direction by applying energy such as heat or electricity, but may expand in a negative direction, that is, contracts. That is, when energy is applied in a state where no energy is applied, only one of expansion and contraction is deformed from the beginning. Here, the act of applying another kind of energy or the like that cancels out the effect of the application of energy for expansion, such as supplying cold air from the outside to a member that is expanded by the application of thermal energy, is the same as the application of energy in the above sense. Is not considered.
The expandable member may be a metal material. If there is no problem such as heat resistance, a member in which a piezoelectric material is laminated, a member using a magnetostrictive material, or the like may be used.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a sheet manufacturing method and a sheet extrusion die according to the present invention will be described below with reference to the drawings. However, the present invention is not limited to these.

FIG. 1 is a cross-sectional view at the end in the die width direction for manufacturing the sheet of the present invention. This sectional view is shown in FIG.
The end of the base of the present invention is shown by a cut similar to the sectional view taken along the line AA in FIG. In FIG. 1, 13 is a first and a second lip, and 18 is a bolt for fastening each lip. Reference numeral 11 denotes a manifold for widening the resin in the width direction, which is formed into a sheet by slits 12 and extrudes the sheet. Reference numeral 15 denotes a bolt for pushing and pulling the tip of the lip, and a cartridge heater 1 for heating and cooling the bolt to push and pull the lip.
Interior 6 The structure obtained by assembling them constitutes the second lip tip deforming means 26. 19 is a base provided on the lip, and 20 is a push-pull block.
Lip pushing direction adjusting bolt (first inflatable member) 21
Is connected to the push-pull block 20 through the base 19 from the lip tip. In the penetrating portion, the base portion 19 does not prevent the expansion of the lip pushing direction adjusting bolt 21. The lip pull direction adjusting bolt (second inflatable member) 22 is connected between the push / pull block 20 and the base portion 19. The adjustment bolts 21 and 22 are provided with a cartridge heater. The portion (first lip tip deformation means 25) enclosed by the two-dot chain line in FIG. 1 is the portion that best illustrates the present invention.

The lip is pushed and pulled from the neutral point in the following manner. That is, when pressing the lip,
The cartridge heater inserted into the lip pushing direction adjusting bolt 21 is heated to expand the bolt. The pushing direction adjusting bolt 21 pushes the lip tip while being supported by the rigidity of the pushing / pulling block 20 and the lip pulling direction adjusting bolt 22. When pulling the lip, the lip pulling direction adjusting bolt 22 is heated. The pulling direction bolt 22 is connected to the base 19.
The push / pull block 22 is moved in the direction in which the lip is pulled, supported by the rigidity of the lip. The tip of the lip receives a force in the pulling direction via the bolt 21 in the pushing direction.

The adjustment bolt in the lip pulling direction is a cylindrical type, and the pushing direction bolt 21 may be inserted therein. However, in order to reduce the interval between adjacent bolts in the width direction of the base and to perform finer thickness adjustment. It is preferable to arrange pulling direction bolts above and below the pushing direction bolts. The number of bolts in the pulling direction may be one, but when the number of bolts in the pushing direction is one, it is preferable to provide two or more bolts with the bolt interposed therebetween in order to prevent inclination in the vertical direction. Conversely, one pull-direction bolt may be provided, and two push-direction bolts may be provided so as to sandwich the bolt.

In order to efficiently push and pull the tip of the lip, the rigidity of each part is preferably set as follows. That is, it is preferable that the rigidity is set such that the base portion> pulling direction adjusting bolt, the push / pull block> the pushing direction adjusting bolt, and the pulling direction adjusting bolt> the pushing direction adjusting bolt.

The material of each push-pull adjustment bolt may be the same as or different from that of the base. General structural steel, stainless steel, or the like can be used, but heat-resistant steel is more preferably used because it is a site to which high heat is applied. Depending on the conditions of the resin used, an aluminum alloy or a copper alloy may be used. Further, the expansion rate of the bolt may be changed between the pushing direction and the pulling direction according to the adjustment amount of the lip.

For heating the adjustment bolt, a cartridge heater may be inserted inside the bolt, or the outer peripheral surface of the bolt may be covered with a sleeve heater or the like for heating. In consideration of the cooling of the adjustment bolt and the arrangement space, it is more preferable to insert a heater inside.

The push / pull block is a push direction adjusting bolt 2
1 and the pulling direction adjusting bolt 22 are connected to each other, and if thermal interference occurs in this portion, the accuracy of adjusting the thickness of the sheet is deteriorated. Therefore, it is preferable that the push-pull block is made of a heat insulating material. The entire block may be made of a heat-insulating material such as ceramic, or a heat-insulating material may be used for a bush at a bolted portion. In order to prevent thermal interference due to radiation and convection between the pushing direction adjusting bolt and the pulling direction adjusting bolt, a heat insulating material may be provided therebetween. This example is shown in FIG. Insulation member 2
3 is preferably installed as shown in FIG. As the heat insulating member, a member using a ceramic material such as alumina or zirconia or a glass fiber is preferable.

The adjusting bolt may be provided with a cooling means for efficiently lowering the temperature. Efficient cooling is preferable because the response speed of the adjustment bolt can be improved and the thickness can be quickly adjusted. This example is shown in FIG. It is simple and preferable to provide the cooling means 24 as shown in FIG. 3 and use air cooling.

Further, the configuration of the first lip tip deforming means 25 may be used in a portion for adjusting the thickness of the product portion of the sheet as shown in FIG.

With the above configuration, the thickness of the sheet can be adjusted,
In particular, by adjusting the thickness of the edge, the required amount of thickness can be achieved with high accuracy without relying on manual operation, and stable production can be performed without clipping in the sheet stretching step.

[0038]

Example: 1000 kg of polyethylene terephthalate
When the sheet is manufactured under the condition of discharging at a discharge rate of / h, the width profile is set to be flat at room temperature with a width of 1 m and a gap of 1.50 mm so that the deviation in the width direction is ± 10 μm. Prepared the base that had been maintained and assembled. A filter,
When connecting to the extruder, a gasket was provided on the flange of the pipe, and the pipe and the base were connected at the flange portion. After the connection, the cartridge heater was inserted into the base, and heating of the base was started in this state. The temperature was set to 300 ° C., a thermocouple was provided at the tip of the lip of the base, and heating was performed until the temperature reached about 5 hours after saturation.

The structure of the adjusting bolt is SUS
630 was heat-treated, and a pushing direction adjusting bolt having a diameter of 20 mm and a pulling direction adjusting bolt having a diameter of 30 mm were prepared. Heating of adjustment bolt is 100V100W inside
The specified cartridge heater was inserted, and glass wool insulation was installed to prevent thermal interference between the adjustment bolts. The above-mentioned means for adjusting the pulling and pulling were installed only at the end of the base in five sets, and only the push direction adjusting bolt having a diameter of 20 mm was installed in the other product parts.

With the above configuration, before the molten material is discharged, the pushing direction adjusting bolt is heated so that the gap between the product portions is about 1.30 mm, and the lip is pushed in. The gap at the end is 1.30 mm.
The lip was pulled by heating the pulling direction adjusting bolt to 70 mm. According to the base used in this example, the product part of the base is 1.30 mm ±
Thickness adjustment was possible in the range of 90 μm. At the end, about 0.5
The thickness could be well adjusted in the range of mm to 2.7 mm.

In this state, the molten resin was discharged to form a sheet at a rotation speed of the cooling roll of 5 m / min. As a result,
The sheet thickness of the product part on the cooling roll was about 200 μm, and about 1000 μm at the end. Thereafter, the sheet was passed through a stretching step, stretched 4 times in the machine direction and 3 times in the transverse direction, and winding was started. Here, in the product part, thickness unevenness was corrected using a pushing direction adjusting bolt centering on a state of a gap of 1.30 mm, and the end part of the sheet end on the cooling roll was adjusted using an end adjusting means. So that the thickness is about 1400μm
The gap was adjusted to about 1.90 mm by operating the pull direction adjusting bolt. The adjustment was performed by applying feedback control to the heater of the means for adjusting the base from the thickness data measured by the thickness gauge. The time required for the adjustment was approximately 15 minutes.
Thereafter, the sheet speed was increased to a winding speed of about 300 m / min to produce a sheet. At this time, the sheet could be manufactured stably without meandering of the sheet and detachment of the clip. In addition, since the breakage due to the detachment of the clip could be prevented, the loss at the start of the sheet manufacturing could be significantly reduced.

On the other hand, under the same conditions as above, the thickness of the sheet end was adjusted by a die having only the push-direction adjusting bolts. Since the gap could not be opened to 1.50 mm or more, it was impossible to adjust the thickness of the end portion itself. Also, when adjusting the thickness with a manual adjustment bolt to compensate for the disadvantage, the gap adjustment itself was possible, but in order to perform a minute thickness adjustment by operating the adjustment bolt by looking at the thickness gauge, It took about one hour to adjust. In addition, the adjusted thickness profile was also inferior in accuracy to the case of the present invention, and in some cases, the clip was detached in the stretching step during the speed increase. Furthermore, the time required for the adjustment varies depending on the skill of the operator. In the case of a low skill, the adjustment may take two hours or more.

[0043]

As described above, according to the present invention,
In manufacturing the sheet, it is possible to simply and effectively adjust the thickness of the sheet, particularly the thickness at the end. In other words, it is possible to reduce the problems in the process such as clip detachment by enabling high-precision thickness adjustment by utilizing the thermal expansion of the bolt and enabling the thickness adjustment of the sheet end to be performed from the neutral point of the lip deformation. Can be. as a result,
There are no significant losses such as loss of raw materials and fixed costs, that is, costs such as personnel costs and depreciation costs, and further, a great many advantages such as an increase in production capacity can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic view of Example 1 showing a die according to the present invention.

FIG. 2 is a schematic view of Example 2 showing a die according to the present invention.

FIG. 3 is a schematic view of Example 3 showing a die according to the present invention.

FIG. 4 is a schematic view of a process for manufacturing a general sheet.

FIG. 5 is a schematic view of a die for manufacturing a general sheet.

FIG. 6 is a schematic view of Example 4 showing the base of the present invention.

[Explanation of symbols]

 1: Extruder 2: Gear pump 3: Filter 4: Cap 5: Cooling roll 6: Stretching process 7: Winder 8: Thickness gauge 9: Thickness controller 10: Sheet 11: Manifold 12: Slit 13: Lip 14: Side plate 15: Adjustment bolt 16: Heater for adjusting bolt heating 17: Heater for base heating 18: Base fastening bolt 19: Base 20: Push / pull block 21: Push direction adjusting bolt (first inflatable member) 22: Pull direction adjustment Bolt (second inflatable member) 23: heat insulating member 24: cooling means (cooling means for lip tip deforming means) 25: first lip tip deforming means 26: second lip tip deforming means

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Claims (10)

[Claims] 1. A method of manufacturing a sheet, comprising: adjusting a thickness of a sheet by deforming a tip of a die when discharging a molten material from a slit formed at a tip of the die into a sheet. The deformation of the die tip at both ends of the base can be deformed so as to expand or contract from the gap when the gap of the slit is at the neutral point of the deformation of the die tip. A method for manufacturing a sheet, wherein the method is performed by means for deforming a die tip portion using a member. 2. A first lip having a deformable tip, a second lip that mates with the first lip, and a tip of the first and second lips forming a slit. A fixing member for fixing the first and second lips, and a tip of the lip at least at both ends in the width direction of the first lip, so that a gap between the slits is expanded from a neutral point of deformation. A die for sheet extrusion molding, comprising: first lip tip deforming means utilizing an inflatable member, which can be deformed so as to be reduced. 3. An inflatable lip which is capable of deforming a tip of the lip at a widthwise end of the second lip so that a gap between the slits is enlarged or reduced from a neutral point of the deformation. The die for sheet extrusion molding according to claim 2, further comprising a second lip tip deforming means using a member. 4. The first lip tip deforming means includes: a first inflatable member having an expandability in a direction in which a gap between the slits is reduced at a tip of the first lip; and a gap between the slits. The die for sheet extrusion molding according to claim 2 or 3, further comprising a second inflatable member having expandability in a direction in which the sheet expands. 5. The die according to claim 4, wherein the expansion member expands due to thermal expansion of the member. 6. A first lip having a deformable tip, a second lip mated with the first lip, and a tip of the first and second lips forming a slit. A fixing member for fixing the first and second lips, and a lip tip deforming means for deforming the tip of the first lip so as to change the gap between the slits. A push / pull block located on the opposite side of the slit of the first lip tip, a base portion of the first lip provided between the tip and the push / pull block, A first inflatable member coupled to the distal end portion of the first lip and the push / pull block, and a second inflatable member coupled to the base portion and the push / pull block, respectively. thing A die for sheet extrusion molding. 7. The sheet extrusion molding method according to claim 6, wherein the first and second inflatable members at the tip of the first lip are expanded by thermal expansion of the member. Base. 8. The sheet extrusion die according to claim 7, further comprising cooling means for said lip tip deformation means. 9. The die for extruding a sheet according to claim 6, wherein said lip tip deforming means is provided at least at an end in a die width direction. 10. The die according to claim 7, wherein the push-pull block is made of a heat-insulating material.