JPS6313813B2 - - Google Patents

Description

[Detailed Description of the Invention] [A] Technical Field of the Invention The present invention relates to a method for discharging a sheet-forming fluid substance into a film or a plate (hereinafter referred to as a sheet) from a slit in a mouthpiece. The present invention relates to a die for extruding sheet-like objects, and more particularly to an improvement in a die for extruding sheet-like objects having a slit interval adjustment mechanism.

[B] Prior art A molding device that produces a sheet-like product by discharging a viscous sheet-forming fluid material from a slit-shaped mouthpiece, such as a molding device that heats a thermoplastic material to a temperature higher than its melting point to melt it. After that, the material is discharged through a nozzle with a slit, and the material is cooled and solidified to form a sheet-like film, or the thermosetting material is dissolved in a certain kind of solvent to form a molten state, and then the material is discharged through a nozzle with a slit. In molding equipment that removes solvents and produces sheet-like products, making the thickness of the sheet-like material uniform is a basic required function, and when the entire molding equipment is configured for this purpose. It is no exaggeration to say so.

An example of an automatic adjustment cap proposed to make the thickness of such a sheet material uniform is U.S. Patent No.
Specification No. 3940221, and Japanese Patent Application No. 126045 (1983) previously proposed by the present inventors.
As described in Publication No. 16722, by indirectly or directly heating a push-pull transmission mechanism such as a bolt that has been press-set in advance, the interval between the slits of the cap can be reduced by thermal expansion of the heated push-pull transmission mechanism. There are things I'm trying to adjust.

However, all of these methods adjust the spacing between the slits of the cap using a push/pull transmission device that inherently has an error in mechanical accuracy.

In other words, in the method of adjusting the spacing of the slits in the cap by thermal expansion of a preset bolt,
If the lip block that makes up the slit of the cap is pressed and set with sufficient margin within the range of elastic deformation, the elasticity of the lip block will prevent bolt play from becoming a problem in the initial stage, and good adjustment accuracy will be achieved. However, if the amount of pressure set changes over time and the amount of pressure becomes such that the elasticity of the lip block does not work, play in the bolt becomes a problem and adjustment accuracy deteriorates. In the worst case, it becomes impossible to adjust the slit spacing. In addition, if the pressure setting is performed again in order to eliminate this phenomenon, the initial good adjustment accuracy can be obtained again, but there is a limit to the accuracy, for example, 2%.
It was impossible to achieve the following thickness accuracy for the sheet-like product.

In other words, with the conventional adjustment method that utilizes the thermal expansion of bolts, it is possible to adjust the thickness to a certain extent by repeating the pressure setting again and again, but it is not suitable for fields that require high thickness accuracy of 2% or less. It was concluded that it was inappropriate. Furthermore, if the pressure set were to be re-executed automatically, the configuration would be extremely complicated.

[C] Objective of the present invention The purpose of the present invention is to provide a die for extruding a sheet-like object, which eliminates the drawbacks of these conventional techniques and achieves a high level of thickness of the sheet-like object. .

[D] Structure of the present invention In order to achieve the above object, the die for extruding a sheet-like material according to the present invention is provided by thermally expanding the spacing between the slits in at least one of a pair of lip blocks that are provided facing each other so as to form slits. In the sheet extrusion die, which has a slit interval adjustment mechanism for extruding a sheet-forming fluid material into a sheet through the slit, the lip block provided with the slit interval adjustment device has a slit interval adjustment mechanism that extrudes a sheet-forming fluid material into a sheet through the slit. A gap is provided in the width direction of the lip block to form a thin wall portion between the lip block, and a portion of the lip block located on the opposite side of the thin wall portion across the gap is a thick wall that is sufficiently thicker than the thin wall portion. A plurality of bridge portions are formed at intervals in the width direction of the lip block, and a plurality of bridge portions are formed in the gap to substantially integrally connect the thin wall portion and the thick wall portion, and a heating element is disposed inside the bridge portion. It is characterized by being buried.

That is, the present invention having the above configuration does not use bolts that cause mechanical play in the slit interval adjustment mechanism itself, but instead uses a bridge portion that is substantially integrally fixed to the lip block in advance and therefore has substantially no play. This was achieved based on the knowledge that a high level of thickness could be achieved for the first time by adopting a structure in which a heating element was embedded inside.

[E] Embodiments of the present invention Next, the present invention will be described using preferred embodiments with reference to the drawings.

FIG. 1 is a diagram showing a schematic configuration of a thermoplastic resin film forming apparatus incorporating a die for extruding a sheet-like material according to the present invention.

In Fig. 1, 1 is an extruder that melts and extrudes thermoplastic resin in a fixed amount, 2 is a conduit that leads the molten resin to the nozzle, 3 is an automatic nozzle equipped with an automatic slit spacing adjustment mechanism, and 4 is the extruder extruded from the nozzle 3. A molten film, 5 a chill roll device for cooling and solidifying the molten film, 6 a thickness gauge, 7 a cooled and solidified film 4
The winding machine 8 calculates the thickness level measured by the thickness gauge 6 and the target thickness level, and commands the adjustment position and adjustment amount to the slit interval adjustment mechanism described below in the automatic mouthpiece 3. It is a computer device that performs

2, 3, and 4 are diagrams showing an automatic adjustment mechanism for the slit interval formed between a pair of lip blocks in order to explain the gist of the present invention. 3 is a partial plan view of the bottom surface of the base 3, and FIG. 4 is a sectional view taken along the line A--A in FIG. 2. In these figures, the slit 33 is formed by providing an appropriate distance between a pair of left and right lip blocks 34, 35 forming the base 3. The lip block 34 has gaps 38, 38a in the width direction of the lip block, that is, in the direction along the slit, so that the rigidity of the thin part 3 is appropriately weakened.
6, 36a are formed. Further, a member 37 is inserted across the width direction of the lip block into the opposite side of the gap 38 from the thin wall portion 36, and this member 37 is completely fixed to the lip block with bolts 50. Together with the member 39, a thick portion is formed which is approximately five times or more thicker than the thin portion.

In addition, members 37, 39 are provided in the gaps 38, 38a.
A plurality of bridge parts 40 each having a thickness of 10 mm and a width of 20 mm are formed in the direction along the slit to integrally connect the thick part and the thin part 36, 36a formed by the slit.
It is spanned at intervals. In this embodiment, the bridge portion 40 includes the thin portions 36, 36a and
It is an integral part that is continuous with the member 39 forming the thick wall part,
Therefore, there is almost no mechanical play.

A rod 10 is installed in this bridge portion 40 from the outside of the lip block 34 toward the slit 33. It is desirable that the rod 10 be located approximately at the center of the bridge portion 40. Further, a heater 11 is embedded as a heating element inside the rod 10 at the bridge 40 portion. A power supply line 12 is extended to the outside of the heater 11, and is connected to an output device of the computer 8 via a heater control device (not shown).

This heater 11 thermally expands the rod 10 and the bridge part 40 by a predetermined amount, and the thin part 36,
It is easy enough to cause push/pull deformation of 36a.

Note that the member 37 has the thin wall portion 3 as described above.
Since it is fixed to the lip block 34 with bolts to prevent slipping when the cap 6, 36a is deformed, the material may be used, but it is preferably made of the same material as the base 3.

Further, in this embodiment, the gap 38 is formed by a member 37 separated from the base 3 in order to facilitate manufacturing, but preferably the member 37 and the base 3 are formed as shown in FIG. Also, it is preferable to form it from one piece as will be described later using FIG.

As shown in FIG. 3, members 41 for preventing leakage of polymer from these ends of the slit 33 in the width direction are provided to the extent that the movement of the slit 33 by pushing and pulling adjustment is not substantially hindered. It is locked by a locking member such as a bolt.

[F] Effect of the present invention Next, the effect of the die for extruding a sheet-like material according to the present invention having the above structure will be explained in more detail.

In FIGS. 1 to 4, when adjusting the distance between the slits 33 by pushing or pulling, the heater 1 is
1 must be heated to an appropriate temperature. After that, the molten resin is discharged and formed, and the thickness level of the formed film 4 is measured with a thickness gauge 6, and the difference from the target thickness level is calculated by the computer 8, and the film thickness is corrected. The position of the push/pull transmission device in the width direction corresponding to the position of the base 3 to be heated and the required amount of thermal expansion are calculated, and the heater 11 generates the amount of thermal expansion in the rod 10 and the bridge portion 40 according to the calculated results. An input electrical signal is commanded. In contrast to the thick parts 37 and 39 that are completely fixed by the bolts 50, the thin parts 36 and 36a have weak rigidity, so the bridge part 40 mainly moves in the direction of the slit 33 due to the heat generated by the rod 10 under the control of the heater 11. The lip block 3 forming the slit 33 is thermally expanded to push and deform the thin-walled portions 36, 36a with low rigidity.
The push/pull amount of step 4 is controlled, thereby adjusting the slit spacing.

When adjusting the slit interval by controlling the heater 11, the heater 11
Since the heating method is directly from the inside of the rod 10, if the heat capacity of the rod 10 and the bridge part 40 is reduced, the heating can be done with good thermal efficiency.
The amount of thermal expansion is quickly controlled in accordance with changes in the input power to the heater 11.

Furthermore, since no rotational push-pull transmission device such as a bolt is used, there is no error due to play during rotation, so the amount of thermal expansion of the rod 10 and bridge portion 40 relative to the input power of the heater 11 is Since it is uniquely determined, it can be controlled with high precision.

In addition, the bridge portion 40 can have a smaller heat capacity by being miniaturized, and since the surrounding area is in contact with the outside air, it is easy to dissipate heat, and the heat is transferred to the thin wall portion 3.
The effect transmitted to 6 and 36a is small. In other words, since the thin wall portions 36 and 36a of the bridge portion 40 act to give almost only push/pull deformation, there is almost no effect on the heat distribution inside the base 3, and the occurrence of flow disturbances due to changes in the viscosity of the resin is suppressed. However, in order to further increase heat dissipation, fins or the like may be provided on the outer circumferential surface of the bridge portion 40, and furthermore, a heat insulating material may be provided between the bridge portion 40 and the thin portion to improve heat transfer from the bridge portion. It is more preferable to shut off the heat, as this eliminates the influence of heat on the cap.

The example shown in FIGS. 2 and 3 is merely an embodiment of the present invention, and the bridge portion 40 that is thermally expanded by the heater 11 and the rod 10 constituting the heating element is aligned with the lip block 34 of the base 3. Although it is made up of several members, it is not necessarily limited to this. However, if a separate member is used, it must be substantially integrated with the lip block body by fastening, connecting means, etc. that have no structural play.

An example thereof will be explained using FIG. 5 and FIG. 6.

FIG. 5 shows a member 60 in which the rod 10 can be embedded, and FIG. 6 is a cross section showing another embodiment of the cap according to the present invention, in which the member 60 is inserted from the thick part of the lip block 34a and fixed to the thin part 36. It is a diagram.

In FIG. 6, the member 60 is completely fixed to the lip block 34a with nuts 61 and 62, so that it functions as a bridge portion 40a that integrally engages the thick portion and the thin portion, and has a structure with virtually no play. . A member 60 forming this bridge portion 40a
A heater 11 is embedded in the rod 10 inserted into the bridge portion 40a in the same manner as shown in FIG.
The thin wall portion 36 is pushed and deformed by the heat-generated expansion.

Further, it is also possible to combine the other lip block 35 forming the base 3 with a conventional push/pull transmission device such as a bolt. In this case, manual or automatic rough adjustment is performed using a push/pull transmission device such as a bolt, and then the adjustment mechanism of the present invention is operated as in the above embodiment, so that the sheet-like material after the start can be adjusted. It is possible to shorten the time required to reach the target thickness level and expand the thickness adjustment range.

It goes without saying that the sheet extrusion die according to the present invention can be attached not only to the lip blocks 34 and 34a, but also to the lip block 35, as described above, in order to expand the adjustment range.

[G] Effects of the present invention As explained above, the sheet material extrusion die according to the present invention has the following characteristics in the width direction of the lip block main body:
In addition, the heating element is embedded within a plurality of bridge portions adjacent to the slit and substantially integrally formed with the lip block main body, that is, the structure does not use a push/pull transmission device such as a bolt. , it is possible to quickly adjust the thickness of the sheet material without causing poor adjustment of the spacing between the cap slits due to the presence of the so-called play area, which occurs when conventional bolts are used, and moreover, with high accuracy. thickness levels can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a film forming apparatus incorporating a die for extruding sheet-like materials according to the present invention, and FIG.
3 is a partial plan view of the bottom surface of the die shown in FIG. 2, FIG. 4 is a sectional view taken along the line A-A in FIG. 2, and FIG. The figure is a sectional view of a member 60 in which the rod 10 can be embedded, and FIG. It is a diagram. Explanation of symbols in the drawings, 3... Base, 6... Thickness gauge, 8... Computer, 10... Rod, 11
...Heater, 33...Slit, 34,35...
Lip block, 36, 36a...thin part, 3
7, 39... member (thick wall part), 38, 38a...
Gap, 40...Bridge part, 50...Bolt.

Claims (1)

[Claims] 1. At least one of a pair of lip blocks provided facing each other so as to form slits has a slit interval adjustment mechanism for adjusting the interval between the slits based on thermal expansion, and the sheet-forming fluid material is passed through the slits into a sheet shape. In a die for extruding a sheet-like material, the lip block provided with the slit interval adjustment device is provided with a gap in the width direction of the lip block that forms a thin wall portion between the lip block and the slit, and the gap in the lip block is A portion located on the opposite side of the thin wall portion across the gap is formed as a thick wall portion having a wall thickness sufficiently thicker than the thin wall portion, and the thin wall portion and the thick wall portion are substantially integrally connected in the gap. A die for extruding a sheet-like material, characterized in that a plurality of bridge portions are formed at intervals in the width direction of the lip block, and a heating element is embedded inside the bridge portion.