JP2006088473A - Manufacturing method of multilayered film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a multilayered film capable of controlling the film thicknesses of the films of respective layers by a conventional known film thickness meter regardless of the materials for constituting the respective layers. <P>SOLUTION: The manufacturing method of the multilayered film includes a process for arranging extrusion dies 14 in the longitudinal direction of the multilayered film 11 in series, a process for casting a resin material on an endless belt 16 from the extrusion dies 14 in a curtain-like state to laminate the resin material, a process for measuring the distances from the surface (reference surface 23) of a backup roller 22 to the exposed surfaces appearing in the respective layers of the multilayered film 11 by a film thickness meter 24 to calculate the thicknesses of the respective layers, a process for controlling the casting amount of the resin material from the extrusion die 14 by regulating the temperature of the lip part 10 of the extrusion die 14 through a heater 12 on the basis of the obtained film thickness data, a process for controlling the casting amount of the resin material from the extrusion die 14 and a process for winding the obtained multilayered film 11 by a winding device 26. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing a multilayer film in which the thickness of each layer is controlled.

  In recent years, there has been an increasing need to add various functions to a base film by laminating resins having different characteristics on the base film to form a multilayer film. For example, a flexible laminated board (a flexible printed wiring board (hereinafter referred to as “FPC”) having a structure in which a circuit made of a metal foil is formed on an insulating film as the electronic product becomes lighter, smaller, and higher in density. .), Etc.) is growing, but multilayer films are suitably used as such insulating films.

  In particular, as demand characteristics such as heat resistance, flexibility, and electrical reliability become stricter, a metal layer is laminated on a base film composed of a polyimide film via an adhesive layer composed of a thermoplastic polyimide compound. A flexible laminate (hereinafter referred to as “two-layer FPC”) has been proposed.

  Such a two-layer FPC can be obtained, for example, by laminating a multilayer film and a metal foil provided with an adhesive layer composed of a thermoplastic polyimide compound on at least one surface of a polyimide film.

  As a method for producing such a multilayer film using a polyimide film as a base film, a solution of a thermoplastic polyimide compound as an adhesive layer on one or both sides of a high heat resistant polyimide film as a base film and / or Alternatively, a precursor solution (hereinafter referred to as “thermoplastic polyimide compound varnish”) is applied by a roll coater or a die coater and dried, or a solution of a highly heat-resistant polyimide compound. And / or a precursor solution (hereinafter referred to as “high heat-resistant polyimide compound varnish”) and a thermoplastic polyimide compound varnish are used in an extrusion die provided in series in the longitudinal direction of the film. Each of which is extruded, laminated and then dried to produce a co-extrusion film-forming method, or first a high heat-resistant polyimide compound varnish After film formation, and then include extrusion casting simultaneous coating method for producing a thermoplastic polyimide-based compound varnish by coating and drying a roll coater or a die coater or the like.

  The above is an example of FPC used in electronics products, but the need for multilayer films is increasing in each industry, and the accuracy of each film thickness dimension is one of the important specifications for any multilayer film. Therefore, adjustment of the film thickness dimension is extremely important in the manufacturing process.

  As a method for adjusting the film thickness dimension, for example, in the case of the extrusion film forming method using the above-described extrusion die, the resin temperature is controlled by a heater embedded in the lip portion of the multilayer die, or the heat provided in the lip portion is used. If the method of adjusting the thickness of the film by controlling the gap of the lip part by expansion and contraction of the bolt or the coating method of applying the resin solution to the above base film, the discharge amount of the coating die There is a method of adjusting the coating film thickness by controlling the gap between the roll coater and the base film.

  However, in any method, it is necessary to actually measure the film thickness dimension of each layer of the formed multilayer film, feed back the film thickness dimension data to each film thickness dimension control means, and adjust and control each film thickness dimension. was there.

  Conventionally, as such film thickness measurement, there is a method of cutting and sampling a molded multilayer film and observing and measuring a cross section with a microscope or the like, but in such a method, measurement data is fed back to the film forming apparatus in a timely manner. There was a problem that I could not. In addition, in the method of measuring the film thickness dimension of each layer online, a non-contact type radiation transmission side length measuring device, a laser length measuring device, or a contact type dial gauge is used as the film thickness meter. Among the thickness gauges, the radiation transmission side length gauge has a mechanism for transmitting radiation through a film and calculating the thickness from the radiation intensity before and after the transmission. For this reason, when radiation was transmitted through the multilayer film, the film thickness was calculated from the radiation intensity transmitted through all the layers, and only the total thickness of the multilayer film could be measured. In laser measuring instruments and contact-type dial gauges, where the laser or gauge needs to contact the surface of each layer, the surface of each layer in the multilayer film is covered with other layers except for the outermost layer surface. Therefore, the film thickness meter cannot be brought into contact with the surface of each layer, and therefore it is impossible in principle to measure the film thickness dimension of each layer of the multilayer film by such a method.

Furthermore, each film thickness dimension has been measured with an infrared absorption method or optical interference method film thickness meter that can measure the film thickness dimension of each layer of the multilayer film, and the film thickness dimension data is fed back to the film thickness control means. However, in the multilayer film in which films having the same infrared absorption spectrum and refractive index are laminated, there is a problem that the film thickness dimension of each layer cannot be measured accurately. there were. Moreover, when changing the material which comprises a film, it was necessary to recollect data, such as an infrared absorption spectrum and a refractive index, again.
JP 2000-71309 A

  In addition, these film thickness meters capture infrared absorption spectra and reflected light wavelengths and analyze them to calculate the film thickness dimension, which tends to increase the time for data acquisition and analysis processing. In addition, it has been difficult to continuously collect film thickness dimensions of each layer of a multilayer film molded by a continuous film manufacturing apparatus. Furthermore, one of the problems is that such a film thickness meter is generally expensive.

  An object of the present invention is a method for producing a multilayer film, and the film thickness of the layers constituting the multilayer film can be controlled by a conventionally known film thickness meter, and regardless of the material constituting each layer. It is providing the manufacturing method of the multilayer film which can be performed.

  The gist of the method for producing a multilayer film of the present invention is that, in the step of producing a multilayer film by laminating resin materials, the step comprises a step of preparing a reference surface and a surface of a layer excluding the outermost layer surface. Preparing a multilayer film with an exposed surface that is partially exposed, each of at least two surfaces selected from either one of the outermost surface and the exposed surface, and the reference surface The step of measuring the distance of the film, the step of calculating the film thickness dimension of the layers constituting the multilayer film from the difference between two values selected from the measured distance value, and the data of the film thickness dimension obtained And adjusting the film thickness of the layers constituting the multilayer film by controlling the amount of the resin material laminated.

  Further, the gist of the method for producing a multilayer film of the present invention is that the reference surface is any one of the outermost layer surfaces, and the step of measuring a distance from the reference surface is performed on the outermost layer surface. The measurement is performed by measuring the distance between each of at least two surfaces selected from the other one and the exposed surface and the reference surface.

  With this configuration, the film thickness of the layer constituting the multilayer film of the present invention is measured by measuring the height from the exposed surface provided on the layer constituting the multilayer film to the reference surface.

  Moreover, the gist of the method for producing a multilayer film of the present invention is that the exposed surface is provided across the width direction of the multilayer film.

  With this configuration, measurement of the film thickness dimension of the layers constituting the multilayer film is performed in the width direction of the film.

  Further, the gist of the method for producing a multilayer film of the present invention is that the resin material is laminated from the extrusion die provided in series in the longitudinal direction of the multilayer film and provided with a film thickness control means. The data is fed back to the film thickness control means.

  Further, the gist of the production method of the multilayer film of the present invention is that the lamination of the resin material is performed by applying the resin material on the object to be laminated by a coating means including a film thickness control means, The data is fed back to the film thickness control means.

  With such a configuration, the film thickness of the multilayer film that is continuously molded is adjusted in a timely manner.

  Moreover, when it is set as the summary of the manufacturing method of the multilayer film of this invention, it exists in the said laminated body being a base film by which film thickness adjustment was carried out beforehand.

  Since the method for producing a multilayer film of the present invention is carried out by measuring the thickness of the layers constituting the multilayer film by measuring the height from the exposed surface to the reference surface provided in the layer constituting the multilayer film, It is possible to use low-cost, high-precision laser length measuring instruments and contact-type dial gauges that have been used, and as a result, inexpensively produce multilayer films with controlled film thickness. can do.

  Moreover, since the manufacturing method of the multilayer film of this invention does not require to measure based on the characteristic (infrared absorption spectrum and refractive index) of each layer which comprises a multilayer film, the multilayer film comprised from which material is comprised. Can be applied.

  Further, the method for producing a multilayer film of the present invention includes a distance value from the reference surface to any one of the outermost layer surfaces of the multilayer film, and a distance from the reference surface to an exposed surface provided in a layer constituting the multilayer film. Arbitrarily select two values selected from these values, and calculate the film thickness dimension of the layers constituting the multilayer film by calculating the difference between them. The film thickness dimension can also be calculated instantaneously by a control device or a sequencer.

  The method for producing a multilayer film of the present invention makes it possible to obtain a multilayer film in which the thickness of each layer is finely adjusted because the film thickness of the layers constituting the multilayer film is controlled in the width direction of the film. .

  FIG. 1 is a first embodiment of a method for producing a multilayer film according to the present invention. FIG. 2 is a cross-sectional view of the backup roller taken along the line A-A ′ in FIG. 1. FIG. 3 shows another embodiment of the extrusion die according to the present invention. FIG. 4 is a cross-sectional view of the multilayer film of the present invention in which the exposed surface is provided at one end of the film. Moreover, FIG. 5 is 2nd Embodiment of the manufacturing method of the multilayer film concerning this invention. Moreover, FIG. 6 is 3rd Embodiment of the manufacturing method of the multilayer film concerning this invention. FIG. 7 is a perspective view of the multilayer film according to the present invention in which exposed surfaces are provided at various locations.

  According to FIG. 1, the multilayer film manufacturing method of the present invention is different according to the process of preparing an extrusion die 14 having different discharge port widths and having a heater 12 at the lip portion 10, and the flow direction of the multilayer film 11. A step of arranging the extrusion dies 14 in series in the longitudinal direction of the multilayer film 11 so as to gradually reduce the exit width, a step of injecting a resin material into each of the extrusion dies 14, and an endless belt 16 from the extrusion dies 14 A step of casting the resin material in a curtain shape and laminating the resin material, and a step of heating the laminate (multilayer film 11) of the resin material in the drying furnace 18 to obtain a self-supporting multilayer film 11; A step of peeling off the self-supporting multilayer film 11 from the endless belt 16 and stretching and heating in the tenter furnace 20 in the width direction and / or the flow direction of the film; The step of bringing the heated multilayer film 11 into contact with the backup roller 22 and the distance from the surface (reference surface 23) of the backup roller 22 to the exposed surface 28 appearing on each layer of the multilayer film 11 is measured with a film thickness meter 24. The step of calculating the film thickness of each layer and the temperature of the lip portion 10 of the extrusion die 14 are adjusted via the heater 12 based on the obtained film thickness data, and the casting amount of the resin material from the extrusion die 14 is adjusted. A step of controlling, and a step of winding the obtained multilayer film 11 by the winding device 26.

  Here, the thickness of each layer is calculated according to FIG. 2. First, the distance from the exposed surface 28 appearing on each layer of the multilayer film 11 to the surface of the backup roller 22 (reference surface 23), and the outermost layer of the multilayer film 11. Each distance from the layer surface 29 to the surface of the backup roller 22 is measured, and then the distance in the lower layer adjacent to the layer whose thickness is to be determined is subtracted from the distance in the layer whose thickness is to be determined.

  In the method for producing a multilayer film according to the present invention, the lamination of the resin materials is not limited to an embodiment in which each resin material is cast from one extrusion die 14 onto the endless belt 16, and is shown in FIG. Thus, each resin material may be cast on the endless belt 16 by using one extrusion die 14 having a plurality of flow paths 30.

  In addition, the lamination of the resin material is not limited to an embodiment performed using the extrusion die 14, and may be performed by applying the resin material to the object to be laminated using a roll coater, a die coater, or the like. In addition, as a method of providing the exposed surface 28 in each layer of the multilayer film 11 formed according to such an embodiment, for example, a die coater having a different discharge port width is formed so that the discharge port width is gradually narrowed according to the flow direction of the multilayer film 11. The roll coaters having different roll widths are arranged in series in the longitudinal direction of the multilayer film 11 so that the roll width gradually decreases in accordance with the flow direction of the multilayer film 11. The aspect to set can be mentioned.

  In the method for producing a multilayer film of the present invention, the position of the exposed surface 28 provided on the multilayer film 11 is not limited to an embodiment provided at both ends in the width direction of the film, and as shown in FIG. The aspect provided in the one end part of may be sufficient.

  In the method for producing a multilayer film of the present invention, the measurement of the distance from each exposed surface 28 of the multilayer film 11 to the surface of the backup roller 22 may be performed using any film thickness meter 24. Specifically, A non-contact type radiation transmission type length measuring device, a laser length measuring device, a contact type dial gauge, etc. can be mentioned.

  Here, the laser length measuring device (for example, LT9000 (manufactured by Keyence)) irradiates the surface of the measurement object with laser light and precisely measures the focal length, and the distance can be measured without contacting the measurement surface. Can be measured. For this reason, when the obtained multilayer film 11 has a surface that is easily damaged, or when it has a sticky surface due to the characteristics of the resin material used, or the thickness measurement of the multilayer film 11 before drying. When it is necessary, such measurement is preferably performed using a laser length measuring device.

  In the step of calculating the film thickness of each layer, the operation of appropriately selecting and subtracting two values from the measured distance value may be performed manually or using a known arithmetic processing unit 32. Is preferred. With this configuration, the thickness of each layer can be calculated instantaneously.

  In the method for producing a multilayer film of the present invention, the temperature of the lip portion 10 may be adjusted by manually adjusting the set temperature of the heater 12 based on the calculated film thickness data of each film. Preferably, the film thickness data is transmitted to the heater 12 online, and the set temperature of the heater 12 is adjusted based on the data. By this aspect, the film thickness control of the multilayer film 11 can be automated.

  In the method for producing a multilayer film of the present invention, before the step of winding up the multilayer film 11, a step of cutting the end in the width direction of the multilayer film 11 with the cutting device 34, and a cut piece collecting device 36 for cutting the cut piece. It is preferable that it is comprised including the process collect | recovered by. With this configuration, since the end portion of the multilayer film 11 that is not a multilayer is removed by providing the exposed surface 28, the multilayer film 11 that does not have a defective portion of the exposed surface 28 can be manufactured.

  In many film manufacturing apparatuses, both end portions in the width direction of the film are used as support portions in a tenter furnace (stretch drying step), and after the drying step, both ends in the width direction are taken before the step of winding and collecting the film. Since the part is cut off into a product, the cutting step does not cause any trouble in the method for producing a multilayer film of the present invention.

  The resin material used in the method for producing a multilayer film of the present invention is not particularly limited as long as it can be laminated, and examples thereof include polyethylene, polyester, and polyimide. Moreover, these precursors, copolymers, mixtures and the like may be used. Moreover, the resin material which contained additives, such as carbon, in these may be sufficient. In addition, when the resin material is laminated by extruding the resin material with an extrusion die or coating with a roll coater or die coat, the resin material needs to be a resin fluid. The resin material may be realized in a molten state or in a solution state.

  Specifically, the resin material is preferably composed of a combination of a thermoplastic polyimide compound varnish and a high heat resistant polyimide compound varnish. The multilayer film 11 having a thermoplastic polyimide compound layer provided on at least one surface of the highly heat-resistant polyimide compound layer obtained by such a structure not only has excellent heat resistance, but the thermoplastic polyimide compound is an adhesive at a high temperature. Since it assumes a role, it becomes easy to affix an insulating film (high heat resistance film) to a copper foil etc. with a thermocompression bonding method, and it can be set as the highly efficient polyimide film for printed circuit boards.

  As mentioned above, although the embodiment of the manufacturing method of the multilayer film of this invention was explained in full detail, this invention is not limited to the above-mentioned embodiment, It can implement also with another aspect.

  The lamination of the resin material in the method for producing a multilayer film of the present invention is not limited to an embodiment in which the resin material is extruded or coated on the endless belt 16, and the film thickness is adjusted in advance as shown in FIG. A resin material may be extruded on the substrate film 38 with the extrusion die 14 or coated with the die coat 42.

  Here, the material of the base film 38 is not particularly limited, and may be metal, paper, or cloth in addition to the resin material. In the case where the base film 38 is a resin film, the resin material is laminated by, for example, as shown in FIG. 6, a resin material that becomes the base film 38, a laser length measuring device 40, an arithmetic processing unit 32, The film formation and drying may be performed while controlling the film thickness with the heater 12 provided on the extrusion die 14, and another resin material may be applied with the die coat 42.

  In the method for producing a multilayer film of the present invention, the step of preparing the multilayer film 11 having the exposed surface 28 includes arranging a die so that the discharge port width becomes smaller according to the flow direction of the film, and using the die, a resin material It is not limited to the mode of extruding or coating, or arranging a roll coater so that the roll width becomes smaller according to the flow direction of the film, and applying a resin material using such a roll coater. Alternatively, the outer peripheral diameter at a desired position in the width direction of the roll coater may be made smaller than the other outer peripheral diameters, for example, so as to provide a portion where the resin material is not applied to the laminate. Moreover, after producing the multilayer film 11 which does not have the exposed surface 28 except the outermost layer surface of the multilayer film 11 using the die | dye with the same discharge port width | variety, some desired positions of the multilayer film 11 are made arbitrary. It may be performed by cutting into a shape or the like. Further, the resin material may be extruded from the die or applied intermittently to provide a portion where the resin material is not laminated across the width direction of the multilayer film 11. An embodiment of the multilayer film 11 obtained by such a method is shown in FIG. With this configuration, the thickness of each layer in the width direction of the film can be adjusted, so that the multilayer film 11 in which the thickness is controlled with higher accuracy can be obtained.

  In addition, when the exposed surface 28 is provided across the width direction of the multilayer film 11, the film thickness measurement of each layer is performed by installing several film thickness meters 24 in the width direction of the multilayer film 11 or by one film. By moving the thickness gauge 24 in the width direction of the multilayer film 11, it is possible to carry out across the entire width direction.

  In addition, when the exposed surface 28 is provided across the width direction of the multilayer film 11, it is not possible to remove such a non-multilayer portion by merely cutting the end portion of the multilayer film 11. In order to increase production efficiency, the apparatus employs a method in which a wide film is once formed and then cut into a fixed size. An exposed surface 28 provided across the width direction of the film is provided at the part to be cut. If it arrange | positions, it can prevent that the site | part which is not a multilayer is contained in the multilayer film 11 obtained.

  The reference surface 23 provided in the method for producing a multilayer film of the present invention may be any one that can provide a reference value from the film thickness meter 24 when calculating the film thickness of each film of the multilayer film 11. The surface is not limited to the reference surface, and the surface of the stainless belt or the position (height) where the film thickness meter 24 is provided may be the reference surface. Further, when the resin material is laminated by extruding or applying the resin material onto the base film 38 whose film thickness has been adjusted in advance, the surface of the base film 38 may be a reference plane. Furthermore, when the film thickness meter 24 is a type of film thickness meter 24 that measures the film thickness while sandwiching the film, one of the outermost layer surfaces of the multilayer film 11 may be a reference surface.

  In the method for producing a multilayer film of the present invention, the amount of resin material cast is controlled by adjusting the resin amount extruded from the extrusion die 14 by controlling the resin temperature with the heater 12 embedded in the lip portion 10 of the extrusion die 14. It is not limited to the embodiment to be performed, and even if it is an embodiment in which the thickness of the film is adjusted by controlling the gap of the lip portion 10 by expansion and contraction of a heat bolt provided in the lip portion 10, or a roll coater and a laminated layer The aspect which adjusts the thickness of a film by controlling the gap | interval with a thing may be sufficient.

  In addition, the present invention can be carried out in a mode in which various improvements, modifications, and variations are added based on the knowledge of those skilled in the art without departing from the spirit of the present invention.

  Hereinafter, the present invention will be described more specifically by way of examples. However, the present invention is not limited to these examples.

(Synthesis Example 1; Synthesis of Polyamic Acid as Precursor of High Heat-Resistant Polyimide Compound)
239 kg of N, N-dimethylformamide (hereinafter referred to as “DMF”) cooled to 10 ° C., 6.9 kg of 4,4′-oxydianiline (hereinafter referred to as “ODA”), p-phenylenediamine ( Hereinafter, it is referred to as “p-PDA”.) 6.2 kg, 2,2-bis [4- (4-aminophenoxy) phenyl] propane (hereinafter referred to as “BAPP”) 9.4 kg are dissolved, 10.4 kg of pyromellitic dianhydride (hereinafter referred to as “PMDA”) was added and dissolved by stirring for 1 hour. Here, 20.3 kg of benzophenone tetracarboxylic dianhydride (hereinafter referred to as “BTDA”) was added and stirred for 1 hour to dissolve.

  A separately prepared DMF solution of PMDA (PMDA: DMF = 0.9 kg: 7.0 kg) was gradually added to the reaction solution, and the addition was stopped when the viscosity reached about 3000 poise. Stirring was performed for 1 hour to obtain a polyamic acid solution of a precursor of a high heat resistant polyimide compound having a solid content concentration of 18% by weight and a rotational viscosity at 23 ° C. of 3500 poise.

Synthesis Example 2 Synthesis of Polyamic Acid as a Precursor of Thermoplastic Polyimide Compound
780 g of DMF and 115.6 g of BAPP were added to a glass flask having a capacity of 2000 ml, and while stirring under a nitrogen atmosphere, 3,3′4,4′-biphenyltetracarboxylic dianhydride (hereinafter referred to as “BPDA”). .) 78.7 g was gradually added. Subsequently, 3.8 g of ethylenebis (trimellitic acid monoester acid anhydride) (hereinafter referred to as “TMEG”) was added and stirred for 30 minutes in an ice bath. A solution in which 2.0 g of TMEG was dissolved in 20 g of DMF was separately prepared, and this was gradually added to the reaction solution while being careful of the viscosity and stirred. When the viscosity reached 3000 poise, addition and stirring were stopped to obtain a polyamic acid solution as a precursor of a thermoplastic polyimide compound.
Example 1

The following chemical dehydrating agent and catalyst were added to the polyamic acid solution (hereinafter referred to as “high heat resistant polyimide compound varnish”) of the precursor of the high heat resistant polyimide compound obtained in Synthesis Example 1, Defoamed. The viscosity of the resulting high heat resistant polyimide compound varnish 1 was 800 poise.
Chemical dehydrating agent: 2 moles of acetic anhydride per mole of amidic acid unit of highly heat-resistant polyimide compound varnish Catalyst: 1 mole of isoquinoline per mole of amic acid unit of highly heat-resistant polyimide compound varnish

  DMF was added to the polyamic acid solution of the precursor of the thermoplastic polyimide compound obtained in Synthesis Example 2 (hereinafter referred to as “thermoplastic polyimide compound varnish”) and diluted. The viscosity of the resulting thermoplastic polyimide compound varnish 1 was 600 poise.

  Extrusion die 1 having a discharge port width of 700 mm, extrusion die 2 having a discharge port width shorter than the extrusion die 1 by 15 mm toward the center and a discharge port width shorter than the extrusion die 2 by a width of 15 mm toward the center An extrusion die 3 was prepared, and this was arranged in order of the extrusion die 3, the extrusion die 2, and the extrusion die 1 from the upstream in series in the flow direction of the multilayer film. In addition, a heat bolt is installed in the lip portion of the extrusion die with a pitch width of 25 mm in the width direction of the die, and the amount of the resin material cast from the extrusion die is adjusted by adjusting the opening of the flow path in the die. It was decided to adjust.

  The thermoplastic polyimide compound varnish 1 is injected into the extrusion dies 1 and 3, and the high heat resistant polyimide compound varnish 1 is injected into the extrusion die 2, and the polyimide compound varnish is moved from each extrusion die at a speed of 15 m / min. Cast on a stainless steel endless belt, heated at 130 ° C. for 100 seconds, peeled off from the stainless steel endless belt, fixed to a tenter clip, and then in a tenter furnace at 300 ° C. for 30 seconds, 400 ° C. It was dried and imidized at 50 ° C and 450 ° C for 10 seconds.

Immediately after coming out of the tenter furnace, the three-layer film after imidation is brought into contact with the backup roller, and the distance between the exposed surface appearing at both ends in the width direction of the three-layer film and the outer peripheral surface of the backup roller is measured by laser. Measure the thickness of each layer with a sequencer, grasp the thickness variation tendency in the width direction from the thickness dimension at both ends of each layer, and feed back to the applied current of the heat bolt installed in each extrusion die Thus, while controlling the thickness, a three-layer film according to the present invention was obtained in which both outer layers were made of a thermoplastic polyimide compound and the central layer was made of a high heat resistant polyimide compound.
(Comparative Example 1)

  Except not carrying out thickness control, it carried out similarly to Example 1, and obtained the three-layer film which both outer layers consist of a thermoplastic polyimide type compound, and a center layer consists of a high heat resistant polyimide type compound.

  As a result of the comparison between Example 1 and Comparative Example 1, in the production of the three-layer film, when the film thickness is not controlled, the film thickness dimension variation of each layer is 20%, whereas the film thickness It was found that when the control is performed, such variation is within 5%.

It is 1st Embodiment of the manufacturing method of the multilayer film concerning this invention. It is A-A 'sectional drawing of the backup roller in FIG. It is other embodiment of the extrusion die concerning this invention. It is sectional drawing of the multilayer film of this invention in which the exposed surface was provided in the one end part of the film. It is 2nd Embodiment of the manufacturing method of the multilayer film concerning this invention. It is 3rd Embodiment of the manufacturing method of the multilayer film concerning this invention. It is a perspective view of the multilayer film concerning this invention in which the exposed surface was provided in various places.

Explanation of symbols

10: Lip part 11: Multilayer film 12: Heater 14: Extrusion die 16: Endless belt 18: Drying furnace 20: Tenter furnace 22: Backup roller 23: Reference surface 24: Film thickness meter 26: Winding device 28: Exposed surface 29 : Outermost layer surface 30: flow path 32: arithmetic processing device 34: cutting device 36: cut piece collection device 38: base film 40: laser length measuring device 42: die coat

Claims (6)

In the process of producing a multilayer film by laminating resin materials, the process comprises:
Preparing a reference surface;
Preparing a multilayer film having an exposed surface where a part of the surface of the layer excluding the outermost layer surface is exposed;
A step of measuring a distance between each of at least two surfaces selected from any one of the outermost surface and the exposed surface, and the reference surface;
From the difference between two values selected from the measured distance value, calculating the film thickness dimension of the layers constituting the multilayer film;
A step of controlling the amount of the resin material laminated based on the obtained film thickness data and adjusting the film thickness of the layers constituting the multilayer film. The reference surface is any one of the outermost layer surfaces, and the step of measuring a distance from the reference surface includes at least two surfaces selected from the other one of the outermost layer surfaces and the exposed surface. The manufacturing method of the multilayer film of Claim 1 performed by measuring the distance of each and the said reference plane. The method for producing a multilayer film according to claim 1, wherein the exposed surface is provided across the width direction of the multilayer film. Lamination of the resin material is performed by casting the resin material on an object to be laminated from an extrusion die provided in series in the longitudinal direction of the multilayer film and provided with a film thickness control means, and the data is the film The method for producing a multilayer film according to claim 1, which is fed back to the thickness control means. 4. The resin material is laminated by coating the resin material on an object to be laminated by coating means having film thickness control means, and the data is fed back to the film thickness control means. The manufacturing method of the multilayer film in any one of. The method for producing a multilayer film according to claim 4 or 5, wherein the laminate is a base film whose film thickness has been adjusted in advance.

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