JPH06155579A - Method for lamination by thermocompression bonding - Google Patents

Abstract

PURPOSE:To obtain a laminate film which is litttle in curl and low in heat seal temperature by a method wherein temperature of a cooling metal roll, pressure of a cooling nip roll, and traveling time of a laminate film are controlled at specific values. CONSTITUTION:A laminate film 7 consisting of a base material film 1 and a sealant film 2 is obtained. Herein, a surface of the base material film 1 is arranged so as to be on an elastic roll 36 side, and a surface of the sealant film 2 is arranged so as to be on a cooling metal roll 35 side. For operating conditions, a surface temperature of the cooling metal roll 35 is 15-65 deg.C, and a nip pressure of a cooling nip roll 42 is 10-90kg/cm. Then, time required by traveling of the laminate film 7 from the heating metal roll 3 to the nip part of the cooling nip roll 42 is made to be within 2sec.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a suitable method for thermocompression-bonding a base film and a sealant film.

[0002]

2. Description of the Related Art It is known to laminate a base material film having excellent mechanical strength and a sealant film having excellent heat-sealing property to provide a packaging material. The most general method conventionally used as such a laminating method is a dry laminating method. This is because a non-printed base film or a pre-printed base film is coated with an adhesive dissolved in an organic solvent, the organic solvent is vaporized in a drying oven, and then the sealant film is pressure-bonded to form a laminated film. However, since the organic solvent is used in the process in this way, the residue of the solvent becomes a sanitary problem, and the health of workers, the risk of fire, waste of resources, and the atmosphere of vaporized gas There were many problems such as pollution.

In view of such circumstances, the present applicant has developed a method and apparatus for laminating only by thermocompression without using a solvent in the manufacturing process, and disclosed it in Japanese Patent Application No. 61-61722. This is a supply angle for automatically adjusting the contact distance between the film A and the film B when the film A and the film B are thermocompression bonded using a thermocompression nip roll composed of a heating roll and a compression roll. After passing through the adjustment roll to the thermocompression nip roll, the other film B is introduced from the pressure roll side to the thermocompression nip roll, subjected to thermocompression lamination, and then passed through the discharge angle adjustment roll for automatically adjusting the contact distance with the heating metal roll. A method and an apparatus for obtaining a laminated film by the method. According to this method and apparatus, in addition to achieving the intended purpose of not using an organic solvent during the process, the amount of heat given to the film from the low speed region at the start of lamination to the high speed steady speed region and the low speed region at the end of lamination is Since it became constant without excess or deficiency, a laminated film of stable quality was obtained without loss, which was very significant industrially.

[0004]

However, it was later found that there may be a problem depending on the type of film used and the intended use. That is, a film that undergoes heat shrinkage at a relatively low temperature, such as a biaxially oriented polypropylene film, is used as the base film, and a film that is relatively easily crystallized, such as an unstretched polypropylene film, is used as the sealant film. After thermocompression-bonding and laminating, a three-sided seal bag or a gas-sealed seal bag was finished, and problems sometimes occurred in applications where a heat-sealing step was performed in a later step. (This also includes so-called automatic packaging machines, which fill the inside of products while making bags.)

This is because, in the method and apparatus illustrated in Japanese Patent Application No. 61-61722, the thermocompression laminated film is a water-cooled discharge angle adjusting roll,
After passing through the tension pickup roll, the film is guided to the cooling nip roll, so that the film is gradually cooled during this period, and when a sealant film such as an unstretched polypropylene film that is easily crystallized is used, its crystallization proceeds,
The obtained laminated film may curl to the sealant film side, and a problem may occur in that the heat sealing temperature for making a three-way sealing bag or a gastric sealing bag must be set high. If the curl is tight, it may be difficult to pass the film through a bag-making machine or an automatic packaging machine.

Further, when the heat-sealing temperature is high, a film such as a biaxially stretched polypropylene film which undergoes heat-shrinking at a relatively low temperature is heat-shrinked, so that the heat-sealing surface becomes uneven and the bag does not look good. In addition, there is also a problem that when the bag is manufactured at a high speed, the entire surface is not heat-sealed exactly, so that a so-called air leakage phenomenon easily occurs.

The present invention solves the above-mentioned drawbacks and provides a method for obtaining a laminate film having a low heat-sealing temperature with little curling and wrinkles when thermocompression-bonding a base film and a sealant film and corresponding to a line speed. PROBLEM TO BE SOLVED: To provide a suitable thermocompression laminating method for a laminated film comprising a biaxially stretched polypropylene-based film layer and a heat-sensitive adhesive film layer, and a laminate film in which a sealant film is a non-stretched polypropylene-based film. With the goal.

[0008]

As a means for achieving the above object, in claim 1, a heating metal roll 3 and an elastic roll 4 are used.
When a laminate film 7 composed of the base material film 1 and the sealant film 2 is obtained by forming a thermocompression-bonding nip roll 30 composed of and a cooling nip roll 42 composed of a cooling metal roll 35 and an elastic roll 36, a base material The surface of the cooling metal roll 35 is 15 to 65 ° C, and the nip pressure of the cooling nip roll 42 is 10 to 90 kg. / Cm,
The laminate film 7 is characterized in that the time required for the film to run from the heated metal roll 3 to the nip portion of the cooling nip roll 42 is within 2 seconds.

In the second aspect, the base film 1 is formed by using the thermocompression nip roll 30 including the heating metal roll 3 and the elastic roll 4, and the cooling nip roll 42 including the cooling metal roll 35 and the elastic roll 36. In obtaining the laminated film 7 including the sealant film 2 and the sealant film 2, the base film 1 was placed so that the elastic roll 36 side was placed and the sealant film 2 side was placed on the cooling metal roll 35 side, and the heating metal roll 3 was separated. Laminating film 7
Is arranged so as to enter the nip portion of the cooling nip roll 42 after first contacting the elastic roll 36.

In the third aspect, the contact angle between the heating metal roll 3 and the base film 1 is automatically adjusted, and / or the contact distance between the heating metal roll 3 and the laminate film 7 is automatically adjusted. Discharge angle adjusting roll 8
Is provided.

In the fourth aspect, the substrate film 1 is a composite film comprising a biaxially stretched polypropylene-based film layer and a heat-sensitive adhesive film layer, and the sealant film 2
Is a method for producing a laminated film which is an unstretched polypropylene film.

[0012]

The surface temperature of the cooling metal roll 35 and the nip pressure of the cooling nip roll 42 are specified to identify the time required for the film to run from the heating metal roll 3 of the laminating film 7 to the nip portion of the cooling nip roll 42, and to laminate. Since the film 7 first comes into contact with the elastic roll 36 and then is arranged so as to enter the nip portion of the cooling nip roll 42, the laminate film 7 can be rapidly cooled and curl does not occur in the laminate film 7.

Since the supply angle adjusting roll 5 and / or the discharge angle adjusting roll 8 are provided, a good thermocompression-bonding laminate corresponding to the line speed can be realized, and the biaxially stretched polypropylene-based film layer and the heat-sensitive adhesive film layer can be obtained. A laminated film of a composite film consisting of and a non-stretched polypropylene film is obtained.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an overall side view showing a preferred example of an apparatus for carrying out the method of the present invention. In FIG. 1, the device frame 1
00 is indicated by a chain double-dashed line, the unwinding portion 10 of the base film 1 is provided at the left end of the frame 100, and the unwinding portion 11 of the sealant film 2 is provided at the right end thereof.
The films 1 and 2 are guided toward the center of the frame 100.

From the unwinding parts 10 and 11 to the frame 10
A tension detector 12 and an edge controller 15 are sequentially provided on the center side of 0. The unwinding parts 10 and 11 are rotated together by the films 1 and 2, and when the tension of the film is relaxed to a set value or more, the tension detecting part 12 operates to unwind the unwinding parts 10 and 11.
When the tension is applied above the set value, the detection unit 12 operates to release the brake.
With this, the unwinding tension is adjusted.

The edge controller 15 comprises two idler rolls 13 and 14 rotatably provided in parallel with the unwinding portions 10 and 11, and a support base 20 for supporting the rolls 13 and 14. The support base 20 is rotatable about the fulcrum shaft 21 provided at the center in the clockwise and counterclockwise directions. This edge controller 15 is a frame 1
It is controlled by the detection member 24 provided on the display unit 00, such as a photoelectric tube. That is, the detection member 24 is configured to detect the deviation of the edge portions of the films 1 and 2 and rotate the edge controller 15 with the fulcrum shaft 21 as a fulcrum in the direction of correcting the deviation so that the film advances correctly. There is.

The preheating nip rolls 16 and 26 are provided in front of the film advancing side of the edge controller 15 and are composed of heating rolls 17 and 27 and elastic rolls 18 and 28. The films 1 and 2 are preheated here and then tensioned. After passing through the detection 22, the substrate film 1 further enters the thermocompression bonding nip roll 30 side through the supply angle adjusting roll 5 on the heating metal roll 3 side.

At this time, the rotating speed of the heating metal roll 3 is a line speed, and the command from the tension detecting section 22 is transmitted to the heating rolls 17 and 27 of the preheating nip rolls 16 and 26, and the command is given depending on the degree of the detected tension. The rotation speed of the rolls 16 and 26 is adjusted.

The supply angle adjusting roll 5 controls the contact distance between the base metal film 1 and the heating metal roll 3 when the base metal film 1 is supplied to the heating metal roll 3. The position is automatically adjusted according to the speed of the roll 3 so that the supply angle is most suitable for the base film 1, that is, the contact distance with the heated metal roll 3.

On the other hand, the sealant film 2 is an elastic roll 4
Is guided to the both films 1 by the thermocompression nip roll 30.
2 is thermocompression bonded to form a laminated film 7. In the present invention, the portion after the contact point in the thermocompression nip roll 30 is referred to as the laminate film 7 and the substrate film 1 and the sealant film 2 are represented before that.

A cooling device, specifically a cooling roll 6, is provided in contact with the elastic roll 4 on the elastic roll 4 side of the thermocompression nip roll 30 to suppress excessive temperature rise of the elastic roll 4. .

The discharge angle adjusting roll 8 is provided on the exit side of the nip roll 30 for thermocompression bonding, and by the circular arc motion as shown by the arrow B, the discharge angle most suitable for the laminate film 7 depending on the speed of the heating metal roll 3, that is, heating. The position is automatically adjusted so as to have a contact distance with the metal roll 3, and the laminate film 7 is separated from the heating metal roll 3 via the roll 8.

At this time, the discharge angle adjusting roll 8 preferably has a small heat transfer coefficient. What happens is that the laminate film 7 heated by the heating metal roll 3 travels without being cooled by the discharge angle adjusting roll 8 and is rapidly cooled by the cooling nip roll 42, so that the sealant film 2 is crystallized. Can be suppressed.

A preferable example of the discharge angle adjusting roll 8 is a roll whose surface is covered with heat resistant rubber such as Hypalon or silicone rubber. Since the surface temperature of the discharge angle adjusting roll 8 during the laminating operation becomes close to the temperature of the laminate film 7, it is desirable that the film surface in contact with the roll 8 is the base film 1 side. This is because, if the sealant film 2 side contacts the roll 8, the sealant film 2 side is softened by heat, so that scratches easily occur and the commercial value is reduced.

Next, in the laminated film 7, the surface of the base material film 1 is on the elastic roll 36 side, and the sealant film 2 is
The thermocompression-bonding laminate is completed by being nipped by the cooling nip roll 42 arranged so that its surface comes to the cooling metal roll 35 and rapidly cooled.

The reason why the sealant film 2 surface is placed on the cooling metal roll 35 side is to make the quenching effect more effective, and the sealant film 2 surface is placed on the elastic roll 3 side.
Since the sealant film 2 surface is softened by heat when it is arranged so as to come to the 6 side, it is for preventing the fine unevenness on the surface of the elastic roll 36 from being easily copied by the cooling nip roll 42 and preventing it from becoming an opaque film. is there.

The surface temperature of the cooling metal roll 35 during the laminating operation is 15 to 65 ° C., preferably 25 to 55.
C., nip pressure of the cooling nip roll 42 is 10 to 90 k
g / cm, preferably in the range of 20 to 50 kg / cm, the laminate film 7 separated from the heated metal roll 3 first contacts the elastic roll 36, then enters the nip portion of the cooling nip roll 42, and The cooling nip roll 42 is positioned such that the time required for the film to run from the moment the laminated film 7 leaves the heated metal roll 3 to the nip portion of the cooling nip roll 42 is within 2 seconds, preferably within 1 second. Are placed.

Preferable examples of the elastic roll 36 include rolls coated with rubber having excellent heat resistance such as Hypalon and silicone rubber. Further, a preferable example of the cooling metal roll 35 is a metal roll having cold water circulated therein.

It is desirable that the surface temperature of the cooling metal roll 35 during the laminating operation is set within the range of 15 to 65 ° C., preferably 25 to 55 ° C. When the temperature is lower than 15 ° C., it is necessary to lower the temperature of cold water to keep such low temperature, which not only increases the cost but also deteriorates the transparency of the laminate film. In addition, depending on the temperature and humidity of the atmosphere, the surface of the roll may condense and a good product may not be obtained.
If the temperature is 65 ° C. or higher, the laminate film 7 is not rapidly cooled, so that curling occurs and the heat sealing temperature of the film becomes high.

The nip pressure of the cooling nip roll 42 during the laminating operation is preferably set within the range of 10 to 90 kg / cm, preferably 20 to 50 kg / cm. When the pressure is less than 10 kg / cm, the pressing pressure is small, so that the laminated film 7 is not rapidly cooled, curling is likely to occur, the heat sealing temperature is high, and only a film having poor transparency can be obtained. When it is 90 kg / cm or more, the durability of the elastic roll 36 is lowered, and the pressure becomes unnecessarily high due to the curl of the obtained film and the heat sealing temperature.

The laminated film 7 separated from the heating metal roll 3 first comes into contact with the elastic roll 36 and then enters the nip portion of the cooling nip roll 42. This is because the laminated film 7 enters the nip portion of the cooling nip roll 42 after it comes into contact with the cooling metal roll 35 without being washed, so that the laminated film 7 starts to be cooled from the moment it comes into contact with the cooling metal roll 35, so that the film is gradually cooled. Not only is it possible to obtain only a film having a high heat-sealing temperature, but since the laminated film 7 comes into contact with the cooling metal roll 35 in a somewhat wavy state, variations in the heat-sealing temperature easily occur, which is not preferable.

Further, even if the laminated film 7 is arranged so as not to come into contact with the elastic roll 36 and the cooling metal roll 35 and directly enter the nip portion of the cooling nip roll 42 in the drawing, the laminated film 7 will be as described above. Since there are many wavy states, there are places where the cooling metal roll 35 comes into contact and places where the cooling metal roll 35 does not come into contact, and only a film having a varying heat sealing temperature can be obtained. After all, it is preferable that the laminated film 7 exiting the thermocompression nip roll 30 first comes into contact with the elastic roll 36 and then enters the nip portion of the cooling nip roll 42.

The contact distance with the elastic roll 36, that is, the winding distance may be appropriately determined depending on the roll diameter of the elastic roll 36, the friction coefficient of the coated rubber, and the like, but a winding distance of 10 mm or more is usually preferable. give. If the thickness is 10 mm or less, the waviness of the laminated film 7 cannot be completely corrected, so that a portion which comes into contact with the cooling metal roll 35 before the nip portion is easily generated is not preferable.

Furthermore, the time required for the film to run from the moment the laminated film 7 leaves the heated metal roll 3 to the nip portion of the cooling nip roll 42 is within 2 seconds, preferably within 1 second. The cooling nip roll 42 is installed at the position. This is because the laminated film 7 is gradually cooled by air during the long running time, and more specifically, the sealant surface of the laminated film 7 heated by the heating metal roll 3 is cooled in a state of higher temperature than its crystallization temperature. The crystallization of the sealant film 2 can be suppressed by entering the nip portion of the working nip roll 42 and rapidly cooling it.

When the traveling time is long, the set temperature of the heating metal roll 3 is raised in advance by the amount of being cooled by air on the way, or the set angles of the supply angle adjusting roll 5 and the discharge angle adjusting roll 8 are set in advance. There is nothing that cannot be complemented by raising it.

In this case, however, the laminated film 7 at the moment when it is separated from the heating metal roll 3 receives excessive heat, so that the heat shrinkage in the width direction becomes extremely large, and a good product cannot be obtained. Therefore, it is preferable to install the cooling nip roll 42 at a position where the time required for the film to run is within 2 seconds, preferably within 1 second. Incidentally, the crystallization temperature of an unstretched polypropylene-based film, which is commonly used as a sealant film, is measured by a differential scanning calorimeter and is in the range of 105 to 115 ° C.

As a result of the discharge angle adjusting roll 8 moving in an arc according to the rotation speed of the heating metal roll 3, that is, the line speed, the distance from the nip portion of the thermocompression nip roll 30 to the nip portion of the cooling nip roll 42 changes. So
The rotation speed of the cooling metal roll 35 is set to the rotation speed of the heating metal roll 3 by draw control, and the draw ratio is automatically changed according to the line speed.
A constant tension is always applied to the laminate film 7.

The laminated film 7 which has been rapidly cooled by the cooling nip roll 42 is then wound by the winding section 33 via the tension detecting section 43.

In this apparatus, the cooling roll 6 is lowered immediately when the machine operation stop button is pressed in order to reduce the extinction region time, that is, increase the average laminating speed, and then the thermocompression nip roll 30 and the cooling nip roll 42 are pressed. The nip opens,
The machine is stopped for a total time of 4 seconds.

Although the above is one preferred embodiment of the present invention, it goes without saying that all other modes can be adopted within the scope of the present invention. In the above-mentioned embodiment, the base material film 1 is arranged on the heating metal roll 3 side and the sealant film 2 is arranged on the elastic roll 4 side.
If the sealant film 2 is a non-polar material such as an unstretched polypropylene film and the surface of the heating metal roll 3 is a non-adhesive finish such as chrome plating or ceramic coating, they will not be heat-sealed. You may arrange | position so that the sealant film 2 may come to the 3 side.

Next, the types of films used in the method of the present invention will be described. In the present invention, any film, sheet or the like can be used as long as they can be heat-bonded to each other, and these are generically referred to as a film. One side thereof is polyamide, polyester, polyolefin or another appropriate thermoplastic resin as a material. Examples of the film include a film obtained by subjecting the base film to a vapor deposition process, and the like.

A more preferable example of the film used in the present invention will be described. The base film 1 is a composite film composed of a biaxially stretched polypropylene film layer and a heat-sensitive adhesive film layer, and the sealant film 2 is a non-stretched polypropylene film. An example is a film. The biaxially stretched polypropylene-based film referred to here means boiling n
A propylene homopolymer having a heptane extraction residue of 90% or more, or an ethylene-propylene copolymer having an ethylene content of 5 mol% or less and having a melting point higher than that of the heat-sensitive adhesive film layer, or a total propylene content. It is a biaxially stretched film composed of a mixture of a propylene homopolymer and a propylene-α-olefin copolymer having a blending amount of 95 mol% or more.

Further, the heat-sensitive adhesive film layer includes polyethylene, ethylene-propylene copolymer, ethylene-butene-1 copolymer, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ionomer system. Polymers mainly composed of ethylene such as polymers, ethylene-propylene copolymers, propylene-butene-1 copolymers,
A film layer made of a polymer mainly composed of propylene such as ethylene-propylene-butene-1 terpolymer can be mentioned as a preferable example, but it goes without saying that any other suitable film layer can be applied. As a method for laminating the biaxially oriented polypropylene film layer and the heat-sensitive adhesive film layer, any known method may be adopted. The heat-sensitive adhesive film layer may or may not be appropriately printed.

On the other hand, the unstretched polypropylene film means an ethylene-propylene copolymer, propylene-butene-, which is commonly used as a sealant film.
1 copolymer, ethylene-propylene-butene-1 terpolymer such as propylene-based polymer or a mixture thereof, and a small amount of ethylene (co) polymer for lowering heat sealing temperature. It also includes those to which is added. The surface of the unstretched polypropylene-based film, which is laminated by thermocompression bonding with the heat-sensitive adhesive film layer of the base film, may or may not be subjected to corona treatment.

[0045]

SPECIFIC EXAMPLE The sealant film 2 was prepared as follows. That is, by a T-die method using a 90 mm extruder, ethylene 3,2 mol% and putene-11,5 mol%
Of ethylene-propylene-butene-1 ternary random copolymer was extruded and taken to have an average thickness of 20 μ,
After corona treatment so that the wetting index on one side was 42 dynes, it was wound up on a roll. At this time, the die temperature was 270 ° C., the take-up roll temperature was 40 ° C., the take-up speed was 30 m / min, and the corona treatment strength was 50 W · min / min.
It was m ² . Then, it was cut into a usable width of 600 mm with a slitter and wound up on a paper tube for 2000 m, and then set in the unwinding unit 11 of the laminate film manufacturing apparatus so that the corona-treated surface of the film was laminated.

On the other hand, the base film 1 was prepared as follows. That is, M. I. 1,6 polypropylene resin was used, and a polypropylene film that had been longitudinally stretched 5 times after T-die extrusion had an ethylene content of 4,5 mol% to form a heat-sensitive adhesive film layer. I. An ethylene-propylene random copolymer of 7.0 was melt-extruded and laminated, and then transversely stretched 8 times to prepare a composite biaxial centrifugal polypropylene film. The polypropylene film layer of the composite film was 37μ, and the heat-sensitive adhesive film layer was 3μ. This composite film is slittered for 620
20 mm by cutting during use, winding up on a paper tube, and then printing on a part of the heat-sensitive adhesive film layer.
A base film having a length of 00 m was obtained, and the base film was set on the unwinding section 10 of the above-mentioned laminated film manufacturing apparatus so that the surface of the heat-sensitive adhesive film layer, which was partially printed, was laminated.

Using the laminating apparatus shown in FIG. 1, the base film 1 and the sealant film 2 thus obtained, a laminated film 7 of about 2000 m was obtained under the following conditions. Preheating temperature of base film 1; 70 ° C., pressure 4 kg / c
m, preheat temperature of sealant film 2; 60 ° C., pressure 4 kg
/ Cm, surface temperature of the heating metal roll 3; 140 ° C., pressure 30 kg
/ Cm, diameter of heating metal roll 3; 400 mm Surface temperature of cooling metal roll 35; 40 ° C. (Before starting lamination, hot water was circulated to 40 ° C. During the lamination operation, the flow rate was adjusted by a solenoid valve. Cold water of 15 ° C. was circulated to 40 ° C.) Diameter of cooling metal roll 35; 400 mm Diameter of elastic roll 36; 280 mm (roll whose surface is coated with silicone rubber) Pressure of cooling nip roll 42; 30 kg / cm Laminate Lamination condition set values which are changed according to time and line speed are shown in FIGS. 4 to 7 below.

The line speed is set corresponding to the laminating operation time as shown in FIG.

The supply angle α ° (FIG. 2) of the supply angle adjusting roll 3 is set corresponding to the line speed as shown in FIG.

The discharge angle β ° (FIG. 2) of the discharge angle adjusting roll 8 is set corresponding to the line speed as shown in FIG.

The rotation speed of the cooling metal roll 35 is controlled based on the draw ratio and the rotation speed ratio of the cooling metal roll 35 / heating metal roll 3 shown in FIG.

Representative examples of the results obtained by examining the heat-sealing temperature, the degree of curl and the transparency (haze) of the thus obtained laminated film 7 of about 2000 m are shown in Tables 1 and 2.

[0053]

Comparative Example 1 A laminated film 7 was obtained in exactly the same manner as in the specific example except that the surface temperature of the cooling metal roll 35 was 70 ° C. The heat sealing temperature, the degree of curling, and the transparency (haze) of this laminated film 7 were examined.
As a typical example, the results for the portion where the laminating speed is 120 m / min are shown in Tables 1 and 2.

[0054]

[Comparative Example 2] The pressure of the cooling nip roll 42 was set to 5 kg /
A laminated film 7 was obtained in exactly the same manner as in the specific examples except that the thickness was changed to cm. The heat sealing temperature, the degree of curling and the transparency (haze) of this laminated film 7 were examined. As a typical example, the results for the portion where the laminating speed is 120 m / min are shown in Tables 1 and 2.

[0055]

Comparative Example 3 A laminated film 7 was obtained under the following conditions using the conventional laminating apparatus shown in FIG. 3, that is, the laminator apparatus disclosed in Japanese Patent Application No. 61-61722. (Under the same conditions as in the specific examples) Base film 1, sealant film 2 Lamination time-line speed Line speed-supply angle set value Line speed-discharge angle set value Preheat temperature of base film 1 Preheat of sealant film 2 Temperature Surface temperature of heating metal roll 3, pressure Roll diameter of heating metal roll 3 Roll diameter, pressure of cooling metal roll 135 (under different conditions from the specific embodiment) Structure of discharge angle adjusting roll 8: water inside A metal roll in which the Teflon coating has been applied to the surface to impart lubricity. The rotation speed control of the heating metal roll 3 and the cooling metal roll 35 is tension control, and the tension applied to the laminate film 7 during this period is 12
The rotation speed of the cooling metal roll 35 was controlled to be kg. The surface temperature of the cooling metal roll 35 was 30 ° C. The laminate film 7 thus obtained was examined for heat sealing temperature, curl degree and transparency (haze). Representative results are shown in Tables 1 and 2.

Evaluation Method of Heat Seal Temperature Using a heat gradient type heat seal tester manufactured by Toyo Seiki Co., Ltd., the sealant film surfaces of the non-printed portions of each laminate film 7 were pressed at a pressure of 2 kg / cm ² × time 0 3 seconds ×
Seal at various temperatures and use the Instron type tensile tester for 2
The longitudinal heat seal strength when pulled at a speed of 00 mm / min is a level that can be practically used, 1.5 kg / 15.
The minimum seal temperature was set to the mm width.

Curl Evaluation Method Each laminate film 7 was cut laterally so as to have a width of 100 mm, and the curl state when left standing on a table was visually determined. ○ No curl (the height of both ends floating above the table is 10 mm or less) △ A little curl (both ends float above the table by 20 mm or more, but does not curl round) × Curl exists (curling round)

Method of evaluating transparency The haze value was measured with a haze meter in accordance with JIS K-6782.

In the laminating apparatus used in the concrete examples,
The time required for the film to run from the moment the laminated film 7 leaves the heating roll 3 to the nip portion of the cooling nip roll 42 is calculated and shown in FIG. That is, it is 2,67 seconds in the speed increasing range of 20 m / min, 2,000 seconds in the speed increasing range of 27 m / min, 1.00 seconds in the speed increasing range of 50 m / min, and 0.32 seconds in the steady speed range of 120 m / min. .

In Table 1, comparing the evaluation results of the specific examples with those of Comparative Example 3, the speed increasing region of 20 m / min (the time required for the film to run was 2,67 seconds, There is no difference in both heat seal temperature and curl, but in the speed increasing region of 27 m / min (the time required for film running is 2,000 seconds, the limit of the range of the present invention),
Both heat seal temperature and curl show fairly good results,
It can be seen that both the heat-sealing temperature and the curl are greatly improved in the speed range from the speed increasing range of 50 m / min / min (time required for film running is 1,00 seconds).

On the other hand, in Comparative Example 1, neither the heat sealing temperature nor the curl was improved so much. It is considered that this is because the surface temperature of the cooling metal roll 35 is high, so that the laminated film 7 is not rapidly cooled and the crystallization is advanced.

Similarly, Comparative Example 2 is not improved so much. It is considered that this is because the pressure of the cooling nip roll 42 was small, and thus the laminated film 7 was not rapidly cooled but was slightly crystallized.

Next, in Table 2, comparing the evaluation results of the specific examples with those of Comparative Example 3, the haze value is slightly inferior. This is because when the film is rapidly cooled by the cooling nip roll 42, the film contracts very slightly and is nipped at a high pressure, but the film is not completely pressed down and slippage occurs between the laminate film 7 and the cooling metal roll 35. It seems that extremely fine irregularities were generated on the surface. However, there is a slight difference in haze value, but there is no difference with the naked eye, as indicated by a transparency evaluation of ◯, which does not reduce the commercial value.

When the haze value of Comparative Example 1 is compared with that of the steady speed range of 120 m / min of the specific example, Comparative Example 1 is slightly inferior. This is probably because crystallization progressed a little. However, as in the case of the transparency evaluation being ◯, Comparative Example 1 has a sufficient commercial value in terms of transparency.

However, Comparative Example 2 has a large haze value of 3, 6 and is a pure white film by visual observation, and the transparency evaluation is x. This is because the nip pressure of the cooling nip roll 42 is small, so that the film shrinks when cooled by the cooling nip roll 42, slippage occurs in the laminate film 7 and the cooling roll 35, and fine unevenness occurs on the film surface. , The irregularities were visible to the naked eye.

[0066]

As described above, according to the present invention, the thermocompression nip roll 3 including the heating metal roll 3 and the elastic roll 4 is used.
0, the cooling nip roll 42 including the cooling metal roll 35 and the elastic roll 36 is used to obtain the laminate fill 7 including the base film 1 and the sealant film 2, and the cooling nip roll 42 is specified under a specific condition range. By placing it in the above, it is possible to provide a laminate film having a low curl and a low heat sealing temperature.

Further, by using the supply angle adjusting roll 5 and / or the discharge angle adjusting roll 8, it becomes possible to perform efficient pressure-bonding laminating corresponding to the line speed, and heat-sensitive adhesion with the biaxially oriented polypropylene film layer. It is possible to manufacture a suitable laminate film of a composite film composed of a flexible film layer and an unstretched polypropylene film.

[Brief description of drawings]

1 is a front view of an embodiment of an apparatus for carrying out the method of the present invention.

FIG. 2 is a front view of a thermocompression nip roll unit of an embodiment of an apparatus for carrying out the method of the present invention.

3 is a front view of the device used in Comparative Example 3. FIG.

FIG. 4 is a graph showing a relationship between line speeds corresponding to laminating operation times.

FIG. 5 is a graph showing a relationship of a supply angle corresponding to a line speed.

FIG. 6 is a graph showing a relationship of a discharge angle corresponding to a line speed.

FIG. 7 is a graph showing the relationship of the draw ratio corresponding to the line speed.

FIG. 8 is a graph showing a relationship of time required for traveling, which corresponds to line speed. 1 ... Substrate film 2 ... Sealant film 3 ... Heating metal roll 4 ... Elastic roll 5 ... Supply angle adjusting roll 7 ... Laminate film 8 ... Discharge angle adjusting roll 35. ..Cooling metal roll 36 ... elastic roll 30 ... nip roll for thermocompression bonding 42 ... nip roll for cooling

[Table 1]

[Table 2]

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hirotaka Tsukiyama 163 Morikawahara-cho, Moriyama-shi, Shiga Gunshi Stock Company Shiga Research Institute (72) Inventor Kazushige Sabo 163 Morikawahara-cho, Moriyama-shi, Shiga Gunshi Stock Company Shiga Research Institute

Claims (4)

[Claims] 1. A thermocompression nip roll 30 comprising a heating metal roll 3 and an elastic roll 4, and a cooling metal roll 35.
When a laminate film 7 composed of the base film 1 and the sealant film 2 is obtained by using the cooling nip roll 42 composed of the elastic roll 36 and the elastic roll 36, the surface of the base film 1 is on the elastic roll 36 side and the surface of the sealant film 2 is The cooling metal roll 35 is arranged so as to come to the side, the cooling metal roll 35 has a surface temperature of 15 to 65 ° C., the nip pressure of the cooling nip roll 42 is 10 to 90 kg / cm, and the laminate film 7 is cooled from the heating metal roll 3. A thermocompression laminating method characterized in that the time required for the film to run to the nip portion of the nip roll 42 for use is within 2 seconds. 2. A thermocompression nip roll 30 comprising a heating metal roll 3 and an elastic roll 4, and a cooling metal roll 35.
When a laminate film 7 composed of the base film 1 and the sealant film 2 is obtained by using the cooling nip roll 42 composed of the elastic roll 36 and the elastic roll 36, the surface of the base film 1 is on the elastic roll 36 side and the surface of the sealant film 2 is on the elastic roll 36 side. The laminate film 7 is arranged so as to come to the cooling metal roll 35 side, and the laminate film 7 separated from the heating metal roll 3 first comes into contact with the elastic roll 36, and then is arranged so as to enter the nip portion of the cooling nip roll 42. Thermocompression laminating method. 3. The heating metal roll 3 and the base film 1
A supply angle adjusting roll 5 for automatically adjusting a contact distance with and / or a discharge angle adjusting roll 8 for automatically adjusting a contact distance between the heating metal roll 3 and the laminate film 7 are provided. Claim 1, Claim 2
The thermocompression laminating method described in. 4. The scope of claim 1, wherein the base film 1 is a composite film composed of a biaxially stretched polypropylene film layer and a heat-sensitive adhesive film layer, and the sealant film 2 is a non-stretched polybrobylene film. The thermocompression laminating method according to claim 1, claim 2, or claim 3.