JP4604336B2 - Base for resin sheet - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a base for a resin sheet, and more particularly to a base for a resin sheet having high versatility that can be applied to molding various types of resin sheets having the same base and different end thicknesses.
[0002]
[Prior art]
As a die for molding a resin sheet such as a resin film, there is a T-type die type. In the T-die die, a pair of lips are assembled so as to form a slit between them, and the molten resin is extruded into a sheet form from the slit. To adjust the thickness of the resin sheet, a plurality of adjusting bolts are attached to the pair of lips along the longitudinal direction of the slit, and the slit gap is adjusted by pushing and pulling each adjusting bolt. It has become.
[0003]
When forming a resin sheet with this die, it is necessary to hold both ends of the resin sheet with a tenter clip, particularly when horizontally stretched. For example, when forming a thin film with a product thickness of about 10 μm The thickness of the both end portions is made thicker than the central product portion. Moreover, by thickening both ends, there is also an effect of suppressing meandering from occurring when performing longitudinal stretching.
[0004]
However, the thickness of both end portions is not the same even when any kind of resin sheet is molded, and has an appropriate size for each type. If the thickness is incomplete, there is a problem that when the lateral stretching is performed, tearing occurs at the end portion, or meandering occurs, resulting in unstable operation. For example, when a thick film having a thickness of 100 μm or more is formed, the film becomes thicker than necessary due to the increase in the thickness of the resin sheet at the outlet of the die. There may be a problem that the clip does not bite. In such a case, on the contrary, adjustment is often made to narrow the slit gap at the end.
[0005]
However, the conventional slit gap adjusting mechanism in the resin sheet die is set mainly for the purpose of adjusting the thickness of the product portion, and therefore the slit gap at the end is limited by the gap adjusted for the product portion. It was. Therefore, if the adjustment bolt is forcibly adjusted to change the gap between the end slits, the base may be deformed and become unusable. Therefore, the conventional bases for resin sheets are generally manufactured for each product type and cannot be applied to many product types.
[0006]
[Problems to be solved by the invention]
An object of the present invention is to provide a highly versatile die for a resin sheet that can be applied to molding various types of resin sheets having the same die and different end thicknesses.
[0007]
[Means for Solving the Problems]
The base for a resin sheet of the present invention that achieves the above object is formed with a slit for discharging a resin sheet between a pair of lips, and an end discharge area of the slit and a product part discharge along the longitudinal direction of at least one lip. In a resin sheet base in which a plurality of gap adjusting mechanisms capable of operating the gap with the area independently from each other are formed, the discharge side end of the lip is formed in a flexible part, and an electric heater is incorporated as the gap adjusting mechanism In addition, a rod that changes the amount of thermal expansion according to the amount of electric energy supplied to the electric heater is provided, the flexible portion is deformed by the thermal expansion of the rod, and the slit gap is adjusted. The rod constituting the gap adjustment mechanism is longer than the rod constituting the gap adjustment mechanism of the product part discharge area, the rod length, the thermal conductivity of the rod material, the thermal expansion coefficient and the rod. To increase the capacity of the heating electric heater, the operation amount of the gap adjusting mechanism of the end ejection area larger than an operation amount of the product portion discharge area of the gap adjusting mechanism and the rod of said end discharge area The diameter is thicker than the diameter of the rod in the product part discharge area .
[0008]
Since the operation amount of the gap adjustment mechanism in the end portion discharge area is made larger than the operation amount of the gap adjustment mechanism in the product portion discharge area in this manner, the precise adjustment capability required in the product portion discharge area is not impaired. The adjustment range of the part thickness is expanded, and the same base can be applied to various types of resin sheets.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows an apparatus for producing a resin sheet equipped with a die of the present invention.
[0010]
The extruder 1 melts the thermoplastic resin and feeds it to the gear pump 2. The gear pump 2 feeds it to the base 4 of the present invention through the filter 3 while measuring it. The die 4 is formed by extruding a molten resin into a resin sheet S, and cooled and solidified by a cooling roll 5 to form an unstretched film.
[0011]
The resin sheet S of an unstretched film is first stretched, for example, 3 to 5 times in the longitudinal stretching device 7, and then stretched laterally, for example, 3 to 4 times while being held by the tenter clips at both ends by the lateral stretching device 8. Then, the product part which is stretched in the intermediate region is wound up in a roll shape by the winder 10 while cutting both end parts which are finally held by the tenter clip.
[0012]
A thickness meter 6 for measuring the thickness of both end portions of the resin sheet S is installed at the front of the longitudinal stretching device 7, and the thickness for measuring the thickness of the product portion of the resin sheet S at the rear of the lateral stretching device 8. A total of 9 is installed. The thickness gauges 6 and 9 need only be installed in a region between the cooling roll 5 and the winder 10, and are not necessarily limited to the positions in the illustrated embodiment.
[0013]
The measurement value signals of the thickness gauges 6 and 9 are input to the control unit 11 and compared with a preset reference value, and then a correction signal corresponding to the difference is obtained from the end discharge area of the discharge slit of the base 4. The thickness is corrected by being sent to a plurality of gap adjusting mechanisms provided in the product discharge area so that they can be operated independently of each other. Here, the correction signal based on the measurement value of the thickness meter 6 is sent to the gap adjustment mechanism in the end portion discharge region, and the correction signal based on the measurement value of the thickness meter 9 is sent to the gap adjustment mechanism in the product portion discharge region. It is supposed to be sent. Details of these gap adjustment mechanisms will be described later.
[0014]
2A to 2C exemplify a base for a resin sheet according to an embodiment of the present invention. FIG. 2A is a partially cutaway front view, and FIG. 2 (A) is a cross-sectional view taken along line XX, and FIG. 2 (C) is a part of a bottom view.
[0015]
The base 4 is constructed such that two horizontally long lips 12 and 12 are assembled so as to form a slit 13 between flexible portions 12a and 12a at the lower end, and side plates 14 and 14 are assembled to both left and right end faces. Has been. A molten resin supply port 15 is provided at the center in the longitudinal direction of the lip, and a manifold 16 is provided so as to extend from the supply port 15 to the left and right sides. The lower edge of the manifold 16 communicates with the slit 13. ing.
[0016]
The molten resin is supplied from the supply port 15 to the manifold 16 and filled with the manifold 16 so as to be uniformly distributed in the entire longitudinal direction of the slit 13, while flowing through the narrow slit 13 while flowing through the narrow slit 13. And discharged. The resin sheet S discharged in this way is configured such that the thickness of the end portion discharge area E at both ends is larger than that of the intermediate product portion discharge area P.
[0017]
Between the flexible portions 12a, 12a arranged so as to sandwich the slit 13 and the fixing portions 12b, 12b provided at the rear thereof, as the gap adjusting mechanism of the slit 13, the end discharge area E is respectively provided. The rod 17e is fixed so that the rod 17p straddles the product portion discharge area P. These rods 17e and 17p incorporate an electric heater (not shown) inside, and change the amount of heat expansion according to the amount of electric energy supplied from the outside to change the amount of thermal expansion. Accordingly, the rods 17e and 17p adjust the gap of the slit 13 in order to fix the fixed portion 12b side and push the flexible portion 12a in accordance with the amount of thermal expansion.
[0018]
In the base 4 of the illustrated embodiment, of the two types of rods 17e and 17p provided for adjusting the gap of the slit 13 as described above, the length Le of the rod 17e in the end discharge region E is the product portion discharge. It is longer than the length Lp of the rod 17p in the region P. Therefore, the total change amount of the thermal expansion of the rod 17e is larger than the total change amount of the thermal expansion of the rod 17p by the length of the entire length, and the operation amount capable of adjusting the gap can be adjusted by the rod 17p of the product portion discharge area P. The amount of operation is larger. Therefore, according to the above-mentioned resin sheet die 4, the adjustment range of the end thickness is expanded, and it is widely used for molding various kinds of resin sheets without being limited in use for each kind as in the conventional die. It becomes possible to use.
[0019]
In the present invention, in order to reliably apply the molding of various types of resin sheets by using one die as described above, the range of the operation amount by the gap adjusting mechanism in the end portion discharge area E is set to the product portion. It is preferable that the amount of operation of the gap adjusting mechanism in the discharge area P is at least twice or more. As described above, as a means for increasing the operation amount by the gap adjustment mechanism in the end portion discharge area E to be larger than the operation amount by the gap adjustment mechanism in the product portion discharge area P, the gap adjustment in the end discharge area E is performed as described above. The rod 17e of the mechanism is made longer than the rod 17p of the gap adjusting mechanism of the product part discharge area P, and a rod material having a high thermal conductivity or thermal expansion coefficient is used, or an electric heater for heating the rod You may use what has a large capacity.
[0020]
In the present invention, the slit length in the end discharge region E is preferably 10 mm or more per side. By setting it as such a length, the holding | grip by the clip at the time of lateral stretching can be ensured. If the slit length of the end discharge area E is shorter than 10 mm, it becomes difficult to prevent film breakage during lateral stretching, no matter how much the grip width of the clip is adjusted.
[0021]
FIG. 3 shows a base for a resin sheet according to another embodiment of the present invention, and shows a part of a bottom view thereof.
[0022]
In this embodiment, the length Le of the gap adjusting rod 17e in the end portion discharge area E is longer than the length Lp of the gap adjusting rod 17p in the product portion discharge area P, as in the embodiment of FIG. In addition to further expanding the adjustment range of the amount of thermal expansion than the product part discharge area P, the width Wp of the flexible part 12a of the lip 12 is also the width Wp of the flexible part 12a in the product discharge part P. By making it thinner, it becomes easier to bend, and the adjustment range of the end thickness is further expanded. Here, the gap adjusting rod 17e in the end portion discharge area E has a diameter De larger than the diameter Dp of the gap adjusting rod 17p in the product section discharge area P, so that the clearance from the flexible portion 12a is increased. It is possible to make it difficult for warp deformation of the gap adjusting rod 17e due to force.
[0023]
FIG. 4 shows a base for a resin sheet according to still another embodiment of the present invention, and shows a part of the bottom view thereof.
[0024]
In this embodiment, in addition to the configuration in which the gap adjustment range of the slit 13 in the end discharge region E is expanded as shown in FIG. 3, the notch groove 18 is provided in the flexible portion 12 a of the lip 12 to make it easier to bend. The gap adjustment range of the slit 13 in the end discharge area E is further expanded.
[0025]
5 (A) and 5 (B) show a base for a resin sheet according to still another embodiment of the present invention, FIG. 5 (A) is a side view, and FIG. 5 (B) is a part of a bottom view.
[0026]
In this embodiment, in addition to the configuration in which the gap adjustment range of the slit 13 in the end discharge region E is expanded as shown in FIG. 3, the enlarged portion 19 of the gap is formed in the slit 13 in the end discharge portion E, and the product The gap between the slits 13 of the partial discharge section P is made larger so that both end portions of the resin sheet S are thicker.
[0027]
6 (A) and 6 (B) show a base for a resin sheet according to still another embodiment of the present invention, FIG. 6 (A) is a side view, and FIG. 6 (B) is a part of a bottom view.
[0028]
In this embodiment, in addition to the configuration in which the gap adjustment range of the slit 13 in the end discharge region E is expanded as shown in FIG. 3, the enlarged portion 20 that extends toward the slit 13 is formed in the manifold 16 in the end discharge portion E. The length of the slit 13 in the discharge direction is shortened so that both end portions of the resin sheet S are thicker than the thickness of the product portion.
[0029]
Each of the above-described caps has an end thickness adjustment range that is increased by making the operation amount of the gap adjustment mechanism in the end portion discharge area larger than the operation amount of the gap adjustment mechanism in the product portion discharge area. Therefore, it can be applied to a plurality of types of resin sheets with the same base.
[0030]
【The invention's effect】
As described above, according to the die for a resin sheet of the present invention, the operation amount of the gap adjustment mechanism in the end portion discharge area is made larger than the operation amount of the gap adjustment mechanism in the product portion discharge area. It becomes possible to apply to various types of resin sheets with the same base.
[Brief description of the drawings]
FIG. 1 is a schematic view showing an example of a resin sheet manufacturing apparatus equipped with a base for a resin sheet of the present invention.
2A and 2B show a base comprising an embodiment of the present invention, in which FIG. 2A is a partially cutaway front view, FIG. 2B is a cross-sectional view taken along the line XX in FIG. It is a bottom view which shows a part.
FIG. 3 is a bottom view showing a part of a base according to another embodiment of the present invention.
FIG. 4 is a bottom view showing a part of a base according to still another embodiment of the present invention.
5A and 5B show a base according to still another embodiment of the present invention, in which FIG. 5A is a side view and FIG. 5B is a bottom view showing a part thereof.
6A and 6B show a base according to still another embodiment of the present invention, in which FIG. 6A is a side view and FIG. 6B is a bottom view showing a part thereof.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Extruder 4 Base 5 Cooling rolls 6, 9 Thickness gauge 7 Longitudinal stretching device 8 Lateral stretching device 10 Winder 12 Lip 12a Flexible portion 12b Fixing portion 13 Slit 16 Manifold 17e, 17p Rod (gap adjustment mechanism)
18 Notch groove

Claims (7)

A plurality of gaps in which a slit for discharging a resin sheet is formed between a pair of lips, and the gap between the end discharge area of the slit and the product discharge area can be operated independently along the longitudinal direction of at least one lip. In the resin sheet base having the adjusting mechanism, the discharge side end of the lip is formed in a flexible part, and an electric heater is incorporated as the gap adjusting mechanism, and thermal expansion is performed according to the amount of electric energy supplied to the electric heater. A rod for changing the amount, the flexible portion is deformed by thermal expansion of the rod to adjust the slit gap, and the rod constituting the gap adjustment mechanism of the end portion discharge area is provided with the product part discharge area. than the rod constituting the gap adjusting mechanism, the length of the rod, the thermal conductivity of the rod material, the thermal expansion coefficient and the volume of the rod heating electric heater is increased, the end ejection An operation amount of the gap adjusting mechanism of frequency is larger than the operation amount of the product portion discharge area of the gap adjusting mechanism, and the diameter of the rod of said end discharge area wider than the diameter of the rod of the product portion discharge area resin sheet die was. The base for a resin sheet according to claim 1 , wherein the thickness of the flexible part of the lip in the end part discharge area is made thinner than the flexible part of the lip in the product part discharge area. The base for a resin sheet according to claim 1 or 2 , wherein a slit gap in the end part discharge area is wider than a slit gap in the product part discharge area. The base for resin sheets in any one of Claims 1-3 which made the length of the slit discharge direction in the said edge part discharge area shorter than the length of the slit discharge direction in the said product part discharge area. The cooling roll which cools and solidifies the resin sheet discharged from this nozzle | cap | die is arrange | positioned under the nozzle | cap | die for resin sheets in any one of Claims 1-4 , and an extending | stretching apparatus and a winding device are downstream of this cooling roll. An apparatus for manufacturing the arranged resin sheet. A thickness meter for measuring the thickness of the end portion of the resin sheet and a thickness meter for measuring the thickness of the product portion are arranged in the region between the cooling roll and the winding device, and the thickness of the end portion is measured. Request clearance adjustment mechanism of the end discharge zone, also with a gap adjusting mechanism of the product portion discharge area based on the measured value of the thickness gauge of the thickness of the product portion so as to control respectively based on the measured value of the meter Item 6. The apparatus for producing a resin sheet according to Item 5 . The manufacturing method of the resin sheet which discharges a resin sheet from the nozzle | cap | die for resin sheets using the manufacturing apparatus of Claim 5 or 6 , and then extends after cooling.

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