JP2006272712A - Manufacturing method of film laminated with polybutylene succinate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a laminated film comprising a polybutylene succinate layer biodegradable and excellent in heat seal property. <P>SOLUTION: The manufacturing method of the laminated film comprising a polybutylene succinate resin comprises the steps of: melt-kneading a polybutylene succinate resin having a melting point of 85-115°C by setting to 230-280°C the temperature for melt-kneading the resin by a screw in the cylinder in an extrusion-lamination apparatus; releasing the resin pressure of the melt-kneaded resin extruded from the heating cylinder and passing it through the next crosshead; melting the gels remaining in the molten resin delivered from the crosshead part in the orifice part inside of the adapter part and feeding to the die part; extruding the molten resin delivered from the adapter part onto a film-like substrate from a T-die extrusion opening in the die part; and pressing and laminating the extruded molten resin layer on the film-like substrate by a cooling roll. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a laminated film material and a laminated sheet material having a polybutylene succinate (PBS) layer, a production method thereof, and a food packaging material produced by the laminated film material and the like.

  There is increasing interest in aliphatic polyester as a biodegradable plastic material in the natural environment, such as polylactic acid (PLA), polybutylene succinate (PBS), polyethylene succinate (PES), polycaprolactone (PCL), etc. There is a growing interest in the development of technology to produce films and sheets manufactured from the company.

  However, it is difficult for the above aliphatic polyesters to have a film or sheet having physical properties that can be used for various purposes, and it is difficult to use them. For example, polylactic acid (PLA) has good printability, high melting point and heat resistance, but it is hard and brittle and has poor heat sealability. It is not suitable for

  Polybutylene succinate (PBS) has a low melting point of about 85 ° C. to 115 ° C. and is excellent in hot tack, so it is excellent as a sealant. However, it has poor strength as a single film or sheet. Its application development has not progressed much due to disasters such as being sufficient and being relatively expensive at this stage.

  Conventionally, attempts have been made to form copolymers of different aliphatic ester monomers in order to solve the poor physical property balance of the aliphatic ester homopolymer as described above. And this can also provide an aliphatic polyester having various properties required for films and sheets for packaging materials, while maintaining the property of aliphatic biodegradability. Known (Patent Document 1, Patent Document 2, etc.).

However, no technology has yet been developed for using aliphatic polyester itself, which is a homopolymer of an aliphatic ester monomer, as a film or sheet for packaging materials. For information on the technology for laminating them, Little has been done so far. In particular, the biodegradability of aliphatic polyester resins has a low melting point, excellent hot tack and heat sealability, and can form packaging materials that can be filled at high speed when used as packaging materials. As for polybutylene succinate (PBS), the development of a technology for enabling its effective use has been awaited.
JP 2004-237473 A Japanese Patent No. 2997756

  The present invention pays attention to the excellent heat sealability of biodegradable polybutylene succinate (PBS), and is a field where development of a new laminate to replace a laminate having a polyethylene resin layer is awaited, for example, the food packaging field Films and sheets containing a polybutylene succinate laminate layer that is biodegradable and excellent in heat sealability (hereinafter referred to as “sheet”, “sheet-like laminate”, “laminate sheet”, “sheet-like substrate”) Is also intended to provide “film”, “film laminate”, “laminate film”, and “film substrate”.

  In the case of a general melt extrusion laminating machine used for extrusion lamination of LDPE resin, in order to obtain a film with a uniform thickness, the needle valve in the cross head of the extrusion laminating machine is throttled and the orifice diameter is narrow. Then, the resin pressure is increased to maintain the melt viscosity at a predetermined value by self-heating, and at the same time, an operation is performed to dissolve the unmelted resin gel and prevent its remaining. However, using the same melt-extrusion laminating machine with polybutylene succinate (PBS) resin, and performing the same extrusion laminating operation as above, the pressure of the crosshead of the extruder suddenly increased and melt-kneading soon after the start of operation. It was found that the load on the screw drive device suddenly increased and the operation became impossible, and stable production was impossible.

  Therefore, in the present invention, an aliphatic polyester resin layer, in particular, a polybutylene succinate resin layer, is melt-extruded and laminated on a substrate surface made of a film or sheet body by a melt-extrusion laminating method using a normal melt-extrusion laminating machine. Developed a technology that makes it possible to provide biodegradable film-like laminates that are useful as food packaging materials with polybutylene succinate (PBS) resin laminate layers that are biodegradable and have excellent hot tack properties It is intended to do.

The present invention for solving the above problems includes the following inventions.
(1) A method for producing a laminated film comprising a series of combination steps for melting and kneading a polybutylene succinate (PBS) resin having a melting point of 85 ° C. to 115 ° C. and continuously melt-extruding and laminating it on a film-like substrate. A step of setting the melt kneading temperature of the resin by the screw in the heating cylinder portion of the extruder in the melt extrusion laminating apparatus to 230 ° C. to 280 ° C. The melt-kneaded resin extruded from the heating cylinder is passed through the crosshead while releasing the resin pressure, and sent to the adapter having an orifice in at least one place. The molten resin remains in the molten resin at at least one orifice in the adapter. The step of melting the gel-like material to make the molten resin uniform and feeding it to the die part, the T-die extrusion port in which the molten resin sent from the adapter part is provided with processing width adjusting means in the die part A step of extruding the film-like substrate surface from the portion, and a step of pressing and laminating the molten resin layer extruded from the T-die extrusion port of the die portion onto the film-like substrate surface to the film-like substrate by a cooling roll. A method for producing a laminated film having a melt-extruded laminate layer made of a polybutylene succinate resin.

(2) A method for producing a laminated film having a melt-extruded laminate layer comprising a polybutylene succinate resin according to (1), wherein the film-like substrate is a film-like substrate formed from a biodegradable material. .

(3) Laminate having a melt-extruded laminate layer made of polybutylene succinate resin according to (2), wherein the biodegradable material is a material selected from biodegradable natural resins, synthetic resins, natural pulp, etc. A method for producing a film.

(4) The polybutylene succinate resin according to any one of (1) to (3), wherein the cooling temperature by the cooling roll is 40 ° C. or lower, preferably 30 ° C. or lower, more preferably 20 ° C. to 30 ° C. A method for producing a laminated film having a melt-extruded laminate layer.

(5) The extrusion width of the melted polybutylene succinate resin film is adjusted by installing a processing width adjusting means comprising a rod rod at the T-die extrusion opening, (1) to (4) A method for producing a laminated film having a melt-extruded laminate layer comprising the polybutylene succinate resin according to any one of the items.

(6) The laminate having a melt-extrusion laminate layer made of polybutylene succinate resin according to (5), wherein the extrusion width adjusting means is a rod rod having a round cross section, a triangle shape or a Y shape. A method for producing a film.

(7) The method for producing a laminated film having a melt-extruded laminate layer made of polybutylene succinate resin according to (5) or (6), wherein the rod rod is a rod rod with a flag.

(8) Heat-sealability having a melt-extruded laminate layer made of polybutylene succinate resin produced by the production method according to any one of items (1) to (7) on a film-like substrate Hot tacky laminated film.

(9) A food packaging material comprising the heat-sealable or hot-tacky laminated film according to (8).

  According to the present invention, a biodegradable polyisocyanate resin has been successfully developed for aliphatic polyester resins, particularly polybutylene succinate resins, for which the field of use has been extremely limited. Stable production and supply of laminated films that have butylene succinate resin as a laminate layer and are useful as food packaging materials that can be filled at high speed with excellent hot tack and heat sealability at commercial production line speeds It becomes possible to do.

  The biodegradable polybutylene succinate resin available as a natural product and other biodegradable natural resins such as aliphatic polyester resin base materials are completely biodegradable and sufficiently Provided is a laminated film capable of forming an environmentally friendly food packaging material having excellent strength, heat sealability, high-speed filling property, and the like.

The laminated film produced by the present invention is a biodegradable resin as a melt-extruded laminate layer on the film-like substrate surface, has flexibility, low melt viscosity, and excellent hot tack and heat-seal properties. It has a polybutylene succinate (PBS) layer.
The raw material of polybutylene succinate may be derived from petroleum or a natural product derived from plants.

  As a base film in the laminated film of the present invention, a resin film body or sheet body usually used as an outer layer material in a heat-sealing food packaging material, a laminated body of aluminum foil and a resin film, paper, etc. Can be mentioned. As a resin film or a resin sheet as a base film, not only a synthetic resin base material such as polypropylene, polyester, polyethylene, polyamide, but also a film made of an aliphatic polyester resin other than an aliphatic polyester resin to be melt-extruded and laminated A sheet body can also be used. When using a biodegradable aliphatic polyester resin film, sheet, paper, etc. as the base film of the present invention, the resulting laminated film becomes biodegradable as a whole, and an environmentally friendly packaging material is used. Can be formed.

The substrate film used in the present invention may have an arbitrary printed layer formed according to the purpose of use.
In addition, an anchor coat layer made of an adhesive usually used for improving the adhesive strength between the base material and the synthetic resin laminate layer is provided on the base material surface on which the polybutylene succinate (PBS) layer is laminated. Can be arranged. Examples of the adhesive for the anchor coat layer include urethane, imine, butadiene, and titanate adhesives.

The laminated film of the present invention is produced by laminating a polybutylene succinate (PBS) layer on a substrate surface, preferably the surface on which an anchor layer is formed, by a melt extrusion laminating method.
Examples of the melt extrusion laminating apparatus used in the method for producing a laminated film of the present invention include a melt extrusion laminating apparatus usually used for melt extrusion laminating of a thermoplastic synthetic resin such as polyethylene. Such a melt-extrusion laminating apparatus melts and kneads a base material supply system that is fed from a base material feeding section and fed to a laminating section through an anchor coat section, and a raw material resin that is fed from a hopper equipped with an autoloader. Pressing the molten resin supply system consisting of an extruder having a screw part in the heating cylinder that is extruded and conveyed, a cross head part, an adapter part and a die part, and a resin layer melt-extruded on the base material and the base material And a cooling roll system to be laminated.

  The manufacturing method of the laminated film of the present invention is a manufacturing method using the melt extrusion laminating apparatus as described above. When the polybutylene succinate layer is melt extrusion laminated using such a standard melt extrusion laminating apparatus, a commercially available polybutylene succinate having a melting point in the range of 85 ° C. to 115 ° C. It is necessary that the temperature of the melt-kneaded resin extruded from the die and the die part temperature are set to be 230 ° C to 280 ° C. When the melt kneading temperature of polybutylene succinate reaches a high temperature state of 300 ° C. or higher, which is the usual melt extrusion temperature of polyethylene, the viscosity of the polybutylene succinate resin becomes too low and the molten resin has a uniform thickness from the die part. It cannot be extruded as a layer.

  In the case of polybutylene succinate, the melt kneading resin temperature at the screw portion in the heating cylinder of the extruder of the melt extrusion laminating apparatus is extruded into the cross head as is done during the melt extrusion lamination of polyethylene or the like. Resin that is detected in the melt kneading resin pressure, feeds back the detected resin pressure information to the screw drive device, and raises the temperature of the melt kneading resin by means such as increasing the rotational speed of the screw. If the control is performed so that the pressure becomes a set value, and the molten resin pressure flowing through the needle valve in the cross head is maintained at the preset resin pressure, the cross will be crossed soon after the start of operation. The resin pressure in the head suddenly increases, and a screw drive is installed to adjust the pressure. Results according load increases beyond the capacity of the driving apparatus, it has been found that the device is shut off device driving power supply will stop.

  Although the exact reason for the above phenomenon is not clear, it is thought that this is caused by the flow characteristics inherent in the melt-kneaded polybutylene succinate resin from the screw portion in the heating cylinder, and at least by the needle valve in the crosshead. If an attempt is made to reduce or eliminate the unmelted resin gel by increasing the molten resin pressure in the crosshead, the molten resin pressure pushed into the crosshead will rise so rapidly that it cannot be controlled soon after the start of operation. .

  As described above, the inventors heated and melted the melt kneading resin temperature suitable for melting and extruding the polybutylene succinate resin in the screw portion in the heating cylinder of the extruder, and detected the melt kneading tree pressure in the crosshead. However, the usual means of adjusting the melt-kneading conditions in the screw portion in the heating cylinder based on the detection information is earnest about the cause that it is impossible to make the polybutylene succinate resin into a molten resin state capable of being melt-extruded. As a result of the examination, if the resin pressure of the molten resin sent to the cross head from the screw part in the heating cylinder of the extruder passes through the cross head as it is released in the cross head, it is set in the screw part in the heating cylinder. The molten resin melted and kneaded at the It found that fed into the coater, in which it was possible to complete the present invention.

  In the melt-extrusion laminating method of the present invention described above, a specific method for allowing the molten resin fed into the cross head from the screw portion in the heating cylinder of the extruder to pass through the cross head as it is while releasing the molten resin pressure in the cross head. As a typical means, it is possible to completely release a needle valve installed for pressure adjustment in a cross head in an extruder of a normal extrusion laminating apparatus.

  In the method of the present invention, the molten resin released by the crosshead portion is then sent to an adapter portion having one or more orifices. The molten resin melts the gel-like material remaining in the molten resin completely at the orifice part in the adapter, and the molten resin is adjusted to an appropriate pressure through the orifice part having a set clearance. Sent to.

  A rod rod for adjusting the width and thickness of the extruded resin film and preventing resin leakage is attached to the extrusion port portion of the die portion. As the rod rod, those having a cross-sectional shape of a round shape, a triangular shape, and a Y shape are used, and those having a shape called a rod rod with a flag are particularly preferably used. By installing such a flagged rod, the width of the resin film supplied to the die extrusion port is reduced, and the both sides of the resin film extruded from the extrusion port are extruded from the die extrusion port. It is possible to prevent the so-called `` neck-in '', in which the portion shrinks in the direction of the center of the membrane, and to adjust the thickness of both side edges of the extruded resin film to be equal to the thickness on the center side. is there. As a result, meandering (surging) of the ear portion of the molten resin film immediately after extrusion can be prevented, and stable laminating can be performed.

  In the present invention, the “rod rod” is a rod having a round cross section shown in FIG. 1 (1), a triangular cross section shown in FIG. 1 (2), and a Y-shaped cross section shown in FIG. 1 (3). Furthermore, the “rod rod with flag” means a member having a flag-like plate-like body at the end of the rod rod as shown in (4) to (7) of FIG. By installing such a guide plate at the die extrusion opening, the side edges of the molten resin film layer are positioned, and the film thickness of both side edges of the molten resin film is made equal to the center of the film. It has a function to control.

  The laminating temperature by the cooling roll after melt extrusion is particularly preferably about 30 ° C. to 10 ° C., for example, lower than the cooling temperature of about 40 ° C. employed at the time of polyethylene resin melt extrusion lamination.

  The method of the present invention provides a polybutylene succinate resin on a normal commercial scale with a processing speed of 80 m / min or more by strictly controlling the lamination conditions of the polybutylene succinate resin to the operating conditions selected as described above. As a result, commercial production of polybutylene succinate resin laminate film that is excellent in heat sealability and hot tack property and can form food packaging material that can be filled at high speed is possible. It is possible to produce on a scale.

  Hereinafter, the present invention will be described in more detail with specific production examples, but the present invention is not limited to these examples.

Production Example 1 (Comparative Production Example)
As a melt-extrusion laminating machine, the first extruder of a diameter 90 mmΦ tandem extruder manufactured by Sumitomo Heavy Industries, Ltd. (manufactured by Sumitomo Heavy Industries, Ltd.) was used. A straight piece having an inner diameter of 20 mmΦ was used for the upper orifice in the adapter portion of the extruder, and a lower orifice having a diameter of 3 mmΦ was used.
A urethane-based AC agent (EL530A / B, manufactured by Toyo Morton Co., Ltd.) is applied to a surface substrate made of a polylactic acid (PLA) resin film (Unitika, Terramac, thickness 25 μm, printed product), and polybutylene succinate (PBS) resin (PBS) resin GS-Pla: AZ81T manufactured by Mitsubishi Chemical Corporation was melt extruded and laminated at a line speed of 100 m / min as a layer having a thickness of 30 μm and a width of 780 mm. The needle valve (pressure regulating valve) in the crosshead at the start of operation was set to open twice as in the LDPE resin extrusion lamination conditions. Moreover, the melt kneading resin temperature in the screw part in the heating cylinder of the extruder was set to 240 ° C. and the extrusion temperature from the die was set to 230 ° C., and the operation was started.

  After the start of operation, the resin pressure extruded into the cross head at a screw rotation speed of 83 rpm becomes abnormally high at 38.0 Mpa, and the load on the screw drive device controlled by detecting the resin pressure increases. Soon after, the load on the screw drive device exceeded the drive limit of the drive device, the power supply of the drive device was cut off, and the laminating apparatus stopped.

Production Example 2
As a melt-extrusion laminating machine, the first extruder of a diameter 90 mmΦ tandem extruder manufactured by Sumitomo Heavy Industries, Ltd. (manufactured by Sumitomo Heavy Industries, Ltd.) was used. A straight piece with an inner diameter of 20 mmΦ was used for the upper orifice in the adapter part of the extruder, and a 15 mmΦ one was used for the lower orifice.
A urethane-based AC agent (EL530A / B, manufactured by Toyo Morton Co., Ltd.) is applied to a front substrate made of a polylactic acid resin (PLA) film (Unitika, Terramac, thickness 25 μm, printed product), and polybutylene succinate (PBS) resin (PBS) GS-Pla: AZ81T manufactured by Mitsubishi Chemical Corporation was melt extruded and laminated as a layer having a thickness of 30 μm and a width of 780 mm at a line speed of 100 m / min. The needle valve (pressure adjusting valve) in the cross head at the start of operation was set to 6 rotations that are almost fully open. Moreover, the melt kneading resin temperature in the screw part in the heating cylinder of the extruder was set to 240 ° C., and the extrusion temperature from the die was set to 240 ° C., and the operation was started.

About 10 minutes after the start of operation, the resin pressure extruded into the crosshead at a screw rotation speed of 83 rpm is constant at 15.0 Mpa, and the resin temperature by the resin thermometer installed in the crosshead is also 261 ° C. A constant value was exhibited, and the temperature of the T dice was 248 ° C. below the die with respect to the set value of 240 ° C.
The prepared surface base film PLA 25 μm (manufactured by Unitika, Terramac, manufactured by Toyo Ink Manufacturing Co., Ltd., 7-color printed product by NEW fine), urethane AC agent (manufactured by Toyo Morton Co., Ltd., EL530A / B) as a solid content of 0. Lamination was performed at a line speed of 100 m / min while performing ozone treatment after coating and drying to ² g / m ² . At this time, a lottery bar of the T die was a triangular bar with a flag (4 in FIG. 1), and the cooling roll temperature of the laminated portion was 20 ° C. As a result, both end faces of the PBS film were within a 1-2 mm surging.

Production Example 3
Using the extrusion laminating machine of Production Example 2, with the same conditions as in Production Example 2 except for the following, bleached kraft paper (basis weight 50 g / m ² , manufactured by Daiko Paper Co., Ltd.), PBS resin (manufactured by Mitsubishi Chemical, GS- (Pla: AZ81T) was melt extruded and laminated as a layer having a thickness of 35 μm. A straight piece having an inner diameter of 20 mmΦ was used for the upper orifice of the 90 mmΦ extruder, and a 10 mmΦ one was used for the lower orifice.
Further, the needle valve (pressure adjusting valve) in the crosshead was almost fully opened with 6 rotations. Lamination was performed by setting the melt kneading resin temperature of the screw part and the resin temperature of the die extrusion port to 245 ° C.
When the screw rotation speed was 86 rpm, the resin pressure in the crosshead became constant at 18.0 Mpa, the resin temperature in the crosshead was 268 ° C., the T die temperature was 245 ° C., and the temperature under the die was stable at 252 ° C.
One-color printing was performed on the surface of the bleached kraft paper substrate, and laminating was performed at a cooling roll temperature of 30 ° C. and a line speed of 100 m / min while performing corona treatment. As a result, a laminated film having such a laminate strength that the PBS resin entered the paper fibers and peeled off was obtained.
Thereafter, in order to confirm the allowable width of the cooling roll temperature, the cooling roll temperature was raised to 40 ° C. As a result, a trouble occurred in which the PBS blocked and wound around the cooling roll.

Production Example 4
Table 1 shows the results of melt extrusion laminating using the same type of extrusion laminating machine as used in Production Example 2 and changing various operating conditions in Production Example 2. The number of times the needle valve in the crosshead was opened was 6 or 7 times.

In Table 1, “push current (%)” indicates the ratio of the current value applied to the drive device in actual operation when the limit current value of the drive device for the screw in the heating cylinder is 100%. Therefore, when the load current value to the drive device exceeds 98%, the drive device is set to stop (the breaker falls).
In order to avoid that the load current value to the drive device exceeds 98%, it is conceivable to increase the melt kneading temperature of the resin in the screw part. However, if the resin temperature becomes high, the molten resin from the die extrusion port Viscosity decreases, surging increases, and film formation cannot be performed, and a laminate having a desired PBS resin laminate layer cannot be manufactured.

  Also, C1 to C5 in the “Cylinder temperature” column indicate the temperatures of the respective parts divided into five from the inlet to the outlet of the screw portion in the cylinder portion, and D1 to D7 in the “T die temperature (° C.)” column indicate the die portion. Shows the temperature in each block divided into 7 blocks

  As is apparent from Table 1, according to the method of the present invention, when the thickness of the molten resin film is about 30 μm to 35 μm, PBS resin is melt-laminated on a commercially feasible scale with a line speed of 100 m / min or more. Can do. In order to avoid that the load current value to the drive device exceeds 98% under the condition that the line speed exceeds 130 m / min, the melt kneading temperature of the resin in the screw portion was also increased, but when the resin temperature becomes high As a result, the viscosity of the molten resin from the die extrusion port was reduced, and as a result, surging was increased, and a laminate having a desired PBS resin laminate layer could not be produced.

<Heat seal characteristics>
Heat sealing characteristics of a polybutylene succinate resin laminate film (polylactic acid resin substrate 25 μm and polybutylene succinate resin layer 35 μm) produced by the method of the present invention, and a laminate formed by melt extrusion of a 30 μm OPP substrate and a 35 μmL DPE layer FIG. 2 shows the heat seal characteristics of the film.
As is clear from FIG. 2, the laminated film having the PBS layer produced by the method of the present invention is a general-purpose OPP / LDPE laminated film (current packaging material) at a heat sealing temperature of up to about 120 ° C. Comparable heat seal properties.

  According to the method for producing a laminated film material having a polybutylene succinate (PBS) layer of the present invention, a biodegradable polybutylene succinate resin and other biodegradable natural resins that are available as natural products, For example, a laminated film capable of forming a food packaging material that is completely biodegradable and has sufficient strength, heat sealability, high-speed filling property, and the like by combination with an aliphatic polyester resin base material is provided. .

The figure which shows schematic shape of the various rod rods installed in T-die exit for adjustment of extrusion processing width and prevention of resin leakage. The figure which shows the heat-sealing characteristic of the PBS layer containing laminated body of this invention.

Claims (9)

  A method for producing a laminated film comprising a series of combined steps for melting and kneading a polybutylene succinate (PBS) resin having a melting point of 85 ° C. to 115 ° C. and continuously melt-extruding and laminating it onto a film-like substrate. A step of extruding the melt-kneaded resin into the crosshead part by setting the melt-kneading temperature of the resin by a screw in the heating cylinder part of the extruder in the extrusion laminating apparatus to 230 ° C. to 280 ° C. A step of passing the melt-kneaded resin extruded from the crosshead while releasing the resin pressure to the adapter portion having an orifice in at least one place, and the molten resin fed from the crosshead portion. At least one orifice in the adapter part remains in the molten resin. The step of melting the material to make the molten resin uniform and feeding it to the die part, the molten resin sent from the adapter part in the die part from the T-die extrusion port part where the processing width adjusting means is installed A step of extruding to the film-like substrate surface, and a step of pressing and laminating the molten resin layer extruded from the T-die extrusion port of the die portion onto the film-like substrate surface to the film-like substrate by a cooling roll. A method for producing a laminated film having a melt-extruded laminate layer made of a polybutylene succinate resin.   The method for producing a laminated film having a melt-extruded laminate layer made of a polybutylene succinate resin according to claim 1, wherein the film-like substrate is a substrate formed of a biodegradable material.   The method for producing a laminated film having a melt-extruded laminate layer comprising a polybutylene succinate resin according to claim 2, wherein the biodegradable material is a material selected from biodegradable natural resins, synthetic resins, natural pulp and the like. .   The method for producing a laminated film having a melt-extruded laminate layer comprising the polybutylene succinate resin according to any one of claims 1 to 3, wherein a cooling temperature by the cooling roll is 40 ° C or lower.   The extrusion width of the melted polybutylene succinate resin film is adjusted by installing a processing width adjusting means comprising a rod rod at the T-die extrusion port. The manufacturing method of the laminated | multilayer film which has a melt-extrusion laminated layer which consists of polybutylene succinate resin of description.   6. The method for producing a laminated film having a melt-extruded laminate layer made of polybutylene succinate resin according to claim 5, wherein the extrusion width adjusting means is a rod bar having a round shape, a triangular shape or a Y shape. .   The method for producing a laminated film having a melt-extruded laminate layer made of a polybutylene succinate resin according to claim 5 or 6, wherein the rod rod is a rod rod with a flag.   A heat-sealable laminated film having a melt-extruded laminate layer comprising a polybutylene succinate resin produced by the production method according to any one of claims 1 to 7 on a film-like substrate.   A food packaging material comprising the heat-sealable laminated film according to claim 8.

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